Recall intervals for oral health in primary care patients

  • Review
  • Intervention

Authors


Abstract

Background

The frequency with which patients should attend for a dental check-up and the potential effects on oral health of altering recall intervals between check-ups have been the subject of ongoing international debate in recent decades. Although recommendations regarding optimal recall intervals vary between countries and dental healthcare systems, six-monthly dental check-ups have traditionally been advocated by general dental practitioners in many developed countries.

This is an update of a Cochrane review first published in 2005, and previously updated in 2007.

Objectives

To determine the beneficial and harmful effects of different fixed recall intervals (for example six months versus 12 months) for the following different types of dental check-up: a) clinical examination only; b) clinical examination plus scale and polish; c) clinical examination plus preventive advice; d) clinical examination plus preventive advice plus scale and polish.
To determine the relative beneficial and harmful effects between any of these different types of dental check-up at the same fixed recall interval.
To compare the beneficial and harmful effects of recall intervals based on clinicians' assessment of patients' disease risk with fixed recall intervals.
To compare the beneficial and harmful effects of no recall interval/patient driven attendance (which may be symptomatic) with fixed recall intervals.

Search methods

The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 27 September 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 27 September 2013) and EMBASE via OVID (1980 to 27 September 2013). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (http://www.who.int/ictrp/en/) for ongoing trials. Reference lists from relevant articles were scanned and the authors of some papers were contacted to identify further trials and obtain additional information. We did not apply any restrictions regarding language or date of publication when searching the electronic databases.

Selection criteria

We included randomised controlled trials (RCTs) assessing the effects of different dental recall intervals.

Data collection and analysis

Two review authors independently assessed the search results against the inclusion criteria of the review, extracted data and carried out risk of bias assessment. We contacted study authors for clarification or further information where necessary and feasible. If we had found more than one study with similar comparisons reporting the same outcomes, we would have combined the studies in a meta-analysis using a random-effects model if there were at least four studies, or a fixed-effect model if there were less than four studies. We expressed the estimate of effect as mean difference with 95% confidence intervals (CIs) for continuous outcomes. We would have used risk ratios with 95% CI for any dichotomous outcomes.

Main results

We included one study that analysed 185 participants. The study compared the effects of a clinical examination every 12 months with a clinical examination every 24 months on the outcomes of caries (decayed, missing, filled surfaces (dmfs/DMFS) increment) and economic cost outcomes (total time used per person). As the study was at high risk of bias, had a small sample size and only included low-risk participants, we rated the quality of the body of evidence for these outcomes as very low.

For three to five-year olds with primary teeth, the mean difference (MD) in dmfs increment was -0.90 (95% CI -1.96 to 0.16) in favour of 12-month recall. For 16 to 20-year olds with permanent teeth, the MD in DMFS increment was -0.86 (95% CI -1.75 to 0.03) also in favour of 12-month recall. There is insufficient evidence to determine whether 12 or 24-month recall with clinical examination results in better caries outcomes.

For three to five-year olds with primary teeth, the MD in time used by each participant was 10 minutes (95% CI -6.7 to 26.7) in favour of 24-month recall. For 16 to 20-year olds with permanent teeth, the MD was 23.7 minutes (95% CI 4.12 to 43.28) also in favour of 24-month recall. This single study at high risk of bias represents insufficient evidence to determine whether 12 or 24-month recall with clinical examination results in better time/cost outcomes.

Authors' conclusions

There is a very low quality body of evidence from one RCT which is insufficient to draw any conclusions regarding the potential beneficial and harmful effects of altering the recall interval between dental check-ups. There is no evidence to support or refute the practice of encouraging patients to attend for dental check-ups at six-monthly intervals. It is important that high quality RCTs are conducted for the outcomes listed in this review in order to address the objectives of this review.

Résumé scientifique

L’intervalle entre les visites de rappel de soins primaires pour la santé bucco-dentaire

Contexte

La fréquence à laquelle les patients devraient se présenter pour un contrôle dentaire et les effets potentiels sur la santé bucco-dentaire en cas de changements des intervalles entre les visites de rappel, ont fait l'objet de débats internationaux au cours de ces dernières décennies. Bien que des recommandations concernant l’intervalle optimal entre les visites de rappel puissent variées selon les pays et selon les systèmes de santé dentaire, les examens dentaires tous les six mois sont traditionnellement préconisés par les dentistes, ceci dans de nombreux pays développés.

Ceci est une mise à jour d'une revue Cochrane publiée pour la première fois en 2005 et précédemment mise à jour en 2007.

Objectifs

Déterminer les effets bénéfiques et néfastes des différents intervalles fixes entre les visites de rappel (par exemple 6 mois versus 12 mois) pour les différents types d’examens dentaires suivants : a) un examen dentaire seul, b) un examen dentaire plus un détartrage et un polissage, c) un examen dentaire plus des conseils préventifs, d) un examen dentaire plus des conseils préventifs, plus un détartrage et un polissage.
Déterminer les effets bénéfiques et néfastes entre ces différents types d’examens dentaires au même intervalle de visites de rappel.
Comparer les effets bénéfiques et néfastes des intervalles de visites de rappel basés sur l’évaluation des risques de maladie des patients lors d’intervalles de visites de rappel fixes.
Comparer les effets bénéfiques et néfastes de l'absence de visites de rappel /fréquentation du patient (qui peut être symptomatique) avec des intervalles de visites de rappel fixes.

Stratégie de recherche documentaire

Les bases de données électroniques suivantes ont été examinées : le registre des essais du groupe Cochrane sur la santé bucco-dentaire (jusqu' au 27 septembre 2013), le registre Cochrane des essais contrôlés (CENTRAL) (la bibliothèque Cochrane 2013, numéro 9), MEDLINE via OVID (de 1946 au 27 septembre 2013) et EMBASE via OVID (de 1980 au 27 septembre 2013). Nous avons effectué des recherches dans le registre d'essais des instituts nationaux de la santé des Etats-Unis (http://clinicaltrials.gov) et le système d’enregistrement international des essais cliniques (http://www.who.int/ictrp/en) pour les essais en cours. Les références bibliographiques des articles pertinents ont été analysées et les auteurs de certaines articles ont été contactés afin d'identifier d'autres essais et d’obtenir des informations supplémentaires. Nous n'avons appliqué aucune restriction concernant la langue ou la date de publication lors des recherches dans les bases de données électroniques.

Critères de sélection

Nous avons inclus des essais contrôlés randomisés (ECR) évaluant les effets de différents intervalles entre les visites de rappel.

Recueil et analyse des données

Deux auteurs de la revue ont indépendamment évalué les résultats des recherches par rapport aux critères d'inclusion de la revue, extrait les données et évalué les risques de biais. Nous avons contacté les auteurs des études pour obtenir des éclaircissements ou des informations supplémentaires lorsque cela était nécessaire et réalisable. Si nous avions trouvé plus d'une étude avec des comparaisons similaires rapportant les mêmes critères de jugement, nous avions combiné les études dans une méta-analyse à l'aide d'un modèle à effets aléatoires s’il y avait au moins quatre études, ou à l'aide d'un modèle à effets fixes s'il y avait moins de quatre études. Nous avons exprimé l'estimation de l'effet par la différence moyenne avec un intervalle de confiance (IC) à 95% pour les résultats continus. Nous avons utilisé les risques relatifs avec des IC à 95% pour tous les critères de jugement dichotomiques.

Résultats principaux

Nous avons inclus une étude qui a analysé 185 participants. L'étude avait comparé les effets d'un examen dentaire, tous les 12 mois avec un examen dentaire, tous les 24 mois sur les critères de jugement concernant les caries (surfaces cariées, manquantes, plombées (SCMP)) et les critères de jugement relatifs au coût (temps total utilisé par personne). Du fait que l’étude était à risque de biais élevé, présentait un échantillon de petite taille et incluait uniquement des participants à faible risque, nous avons évalué la qualité de l'ensemble des preuves pour ces critères de jugement comme très faible.

Pour les enfants de trois à cinq ans avec des dents de lait, la différence moyenne (DM) de l'augmentation du nombre des SCMP était de -0,90 (IC à 95% -1,96 à 0,16), en faveur d’un rappel à 12 mois. Pour les patients de 16 à 20 ans avec des dents permanentes, la DM des SCMP était de -0,86 (IC à 95% -1,75 à 0,03), également en faveur d’un rappel à 12 mois. Il n'existe pas suffisamment de preuves pour déterminer si le rappel de l’examen dentaire à 12 ou à 24 mois résulte de meilleurs critères de jugement relatifs aux carries.

Pour les enfants de trois à cinq ans avec des dents de lait, la DM du temps utilisé pour chaque participant était de 10 minutes (IC à 95% -6,7 à 26,7), en faveur d’un rappel à 24 mois. Pour les patients de 16 à 20 ans avec des dents permanentes, la DM était de 23,7 minutes (IC à 95% 4,12 à 43,28), également en faveur d’un rappel à 24 mois. Cette unique étude à risque de biais élevé ne possède pas suffisamment de preuves pour déterminer si le rappel de l’examen dentaire à 12 ou à 24 mois résulte de meilleurs critères de jugement relatifs au temps/coût.

Conclusions des auteurs

Les preuves de très faible qualité issues d'un ECR sont insuffisantes pour apporter des conclusions concernant les éventuels effets bénéfiques et néfastes sur le changement de l’intervalle entre les visites de rappel d’examens dentaires. Il n'existe aucune preuve permettant d'étayer ou de récuser la pratique d'encourager les patients à subir un examen dentaire à intervalles de six mois. Il est important que des ECR de haute qualité soient réalisés pour les critères de jugement énumérés dans cette revue afin de répondre aux objectifs de cette revue.

Plain language summary

Recall intervals for oral health in primary care patients

Review question

The main question addressed by this review is: what is the optimal interval for dental check-ups (the time period between one dental check-up and the next)?

Background

The effects on oral health and the economic impact of altering the recall interval between different types of dental check-ups are unclear. Primary care dental practitioners in many countries have traditionally recommended dental check-ups at six-monthly intervals.

Study characteristics

The Cochrane Oral Health Group carried out this review of existing studies, which includes evidence current up to 27 September 2013. This review includes one published study in which a total of 185 children and young adults were randomly chosen to have a clinical examination every 12 months or every 24 months. The study measured what effects the two different check-up times had on tooth decay and total time used per person (which could then be used to measure costs to the healthcare system).

Key results

The limited results did not enable a conclusion to be made about whether or not extending the time to the next dental check-up can reduce tooth decay or costs.

Quality of the evidence

The evidence presented is of very low quality due to there only being one study and issues with the way it was conducted.

Résumé simplifié

L’intervalle entre les visites de rappel de soins primaires pour la santé bucco-dentaire

Question de la revue

La principale question examinée dans cette revue est : quel est l'intervalle optimal entre les examens dentaires réguliers (la période entre un examen dentaire et le prochain)?

Contexte

Les effets sur la santé bucco-dentaire et l'impact économique sur le changement de l’intervalle entre les visites de rappel parmi les différents types d’examens dentaires ne sont pas clairs. Dans de nombreux pays, les dentistes en soins primaires recommandent généralement un examen dentaire à intervalles de six mois.

Les caractéristiques de l'étude

Le registre du groupe Cochrane sur la santé bucco-dentaire a mené cette revue des études existantes, qui comprend des preuves mises à jour jusqu' au 27 septembre 2013. Cette revue inclut une étude publiée dans laquelle un total de 185 enfants et jeunes adultes ont été aléatoirement choisi pour un examen clinique, tous les 12 ou 24 mois. L'étude avait mesuré les effets sur la carie dentaire et le temps total utilisé par patient lors des deux différentes périodes d’examen dentaire (qui peuvent alors être utilisés pour mesurer les coûts pour le système de santé).

Résultats principaux

Les résultats limités n'ont pas permis de savoir si oui ou non un délai prolongé avant le prochain contrôle dentaire pouvait réduire la carie dentaire ou les coûts.

Qualité des preuves

Les preuves présentées sont de très faible qualité du fait qu’une seule étude ait été réalisée, de plus, elle présentait des problèmes concernant la façon dont elle a été menée.

Notes de traduction

Traduit par: French Cochrane Centre 14th January, 2014
Traduction financée par: Financeurs pour le Canada : Instituts de Recherche en Santé du Canada, Ministère de la Santé et des Services Sociaux du Québec, Fonds de recherche du Québec-Santé et Institut National d'Excellence en Santé et en Services Sociaux; pour la France : Ministère en charge de la Santé

Laički sažetak

Optimalni vremenski razmaci između kontrolnih pregleda pacijenata kod doktora dentalne medicine

Istraživačko pitanje

Glavno pitanje u ovome pregledu je: koji je optimalni interval između kontrolnih stomatoloških pregleda (vrijeme između dva pregleda u doktora dentalne medicine).

Dosadašnje spoznaje

Učinci na oralno zdravlje i ekonomski utjecaj različitih vremenskih razmaka između kontrolnih pregleda nisu jasni. Liječnici dentalne medicine opće prakse u mnogim zemljama već tradicionalno preporučuju kontrolne preglede u razmaku od šest mjeseci.

Značajke istraživanja

Cochrane skupina za oralno zdravlje (engl. Cochrane Oral Health Group) napravila je sustavni pregled postojećih studija objavljenih do 27. rujna 2013. godine. Ovaj pregled uključuje jednu objavljenu studiju u kojoj je ukupno 185 djece i mladih odraslih nasumično odabrano za klinički pregled svakih 12 mjeseci ili svaka 24 mjeseca. Studija je mjerila učinke tih dvaju različitih vremenskih intervala između kontrolnih pregleda na propadanje zubi te ukupno vrijeme potrošeno po osobi (koje se može koristiti za mjerenje troškova u zdravstvenom sustavu).

Ključni rezultati

Ograničeni rezultati iz pronađene studije ne dopuštaju donošenje zaključka o duljini intervala između kontrolnih pregleda i njihovoj povezanosti sa smanjenjem propadanja zubi i smanjenjem troškova.

Kvaliteta dokaza

Postojeći dokazi su vrlo male kvalitete zbog postojanja samo jedne studije i problema s načinom na koji je provedena.

Bilješke prijevoda

Hrvatski Cochrane
Prevela: Tihana Ilić
Ovaj sažetak preveden je u okviru volonterskog projekta prevođenja Cochrane sažetaka. Uključite se u projekt i pomozite nam u prevođenju brojnih preostalih Cochrane sažetaka koji su još uvijek dostupni samo na engleskom jeziku. Kontakt: cochrane_croatia@mefst.hr

Summary of findings(Explanation)

Summary of findings for the main comparison. Clinical examination at 12 months versus clinical examination at 24 months
  1. 1 Single study at high risk of performance and detection bias with unclear methods of sequence generation and allocation concealment

    2 Only low risk participants who had previously received regular dental care, including health promotion and preventive services were included

    3 Low sample size

Clinical examination at 12 months compared with clinical examination at 24 months for oral health

Patient or population: children and adults

Settings: public dental clinic

Intervention: clinical examination at 12 months

Comparison: clinical examination at 24 months

OutcomesIllustrative comparative risks* (95% CI)No of participants
(studies)
Quality of the evidence
(GRADE)
Assumed riskCorresponding risk
12-month recall24-month recall

Caries (dmfs/DMFS increment) - 3-5 year olds (primary teeth)

Higher values represent worse caries

Follow-up: 2 years

The mean caries score in the 12-month group was 0.9

The mean caries score in the 24-month group was 0.9 higher

(1.96 higher to 0.16 lower)

58
(1 study)
⊕⊝⊝⊝
very low 1, 2, 3

Caries (dmfs/DMFS increment) - 16-20 year olds (permanent teeth)

Higher values represent worse caries

Follow-up: 2 years

The mean caries score in the 12-month group was 0.79

The mean caries score in the 24-month group was 0.86 higher

(1.75 higher to 0.03 lower)

127
(1 study)
⊕⊝⊝⊝
very low 1, 2, 3

Total time (minutes) - 3-5 year olds (primary teeth)

Higher values represent worse time/cost outcomes

Follow-up: 2 years

The mean total time used by each participant in the 12-month group was 52 minutes

The mean total time used by each participant in the 24-month group was 10 minutes lower

(6.7 higher to 26.7 lower)

58
(1 study)
⊕⊝⊝⊝
very low 1, 2, 3

Total time (minutes) - 16-20 year olds (permanent teeth)

Higher values represent worse time/cost outcomes

Follow-up: 2 years

The mean total time used by each participant in the 12-month group was 86.2 minutes

The mean total time used by each participant in the 24-month group was 23.7 minutes lower

(4.12 lower to 43.28 lower)

127
(1 study)
⊕⊝⊝⊝
very low 1, 2, 3
CI: confidence interval; dmfs/DMFS: decayed, missing, filled surfaces
GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Background

Healthcare providers' decisions about when to recall patients for their next visit are common to many outpatient encounters in longitudinal care. Such decisions directly affect provider workloads and have a potentially great impact on healthcare costs and outcomes (Chapko 1999). There is evidence of significant variation in physicians' recommendations about recall intervals (variously called 'revisit intervals', 're-examination intervals' or 'return intervals') for patients with many common ambulatory care conditions including diabetes mellitus, hypertension, angina and musculoskeletal pain (DeSalvo 2000; Petitti 1993; Schwartz 1999; Tobacman 1992). It has been suggested that the existence of such widespread variation may be an indication that physicians are uncertain about what interval is most appropriate and, further, that "a rational, information-based approach to the choice of revisit interval for common conditions could yield substantial savings in medical care costs" (Petitti 1993).

Concerns about the clinical and cost-effectiveness of recall intervals have led to the emergence of research interest in understanding provider behaviour concerning appointment assignment and in the possible beneficial and harmful effects associated with varying recall intervals for specific types of care provided in primary care settings (Chapko 1999; DeSalvo 2000; Schwartz 1999). In this context, there has been a longstanding international debate regarding the clinical effectiveness and cost-effectiveness of recall intervals for routine dental check-up examinations. This review looks at the evidence pertaining to the effects on oral health and the resource implications of different recall intervals for 'dental check-ups'.

Description of the intervention

In the context of the provision of continuing dental care to patients, a 'recall visit' may be defined as "the planned, unprecipitated return of a patient who, when last seen was in good oral health" (Royal College 1997). A 'recall examination' (also referred to as a 'routine dental check-up' or an 'oral health review') is the examination performed at this planned return appointment. The 'recall interval' is the time period, usually specified in months or years, between recall examinations.

There is no universally recognised definition of the term 'routine dental check-up'. A routine dental check-up has been defined in the United Kingdom (UK) National Health Service (NHS) dental remuneration statement as "clinical examination, advice, charting (including monitoring of periodontal status) and report" (NHS Executive 2002). The principal function of the 'clinical examination' component of the check-up is to detect the signs and symptoms of oral disease, in particular dental caries and periodontal disease. The primary dental health team is also regarded as having a role in the early detection of oral malignancy and potentially malignant lesions with a view to having a potential beneficial impact on the overall incidence, morbidity and mortality from oral cancer (Conway 2002). It has been argued that an examination for oral cancer, including a thorough medical and social history and a systematic examination of the oral mucosa, should form an integral part of all routine dental examinations (BDA 2000; Clovis 2002; Conway 2002; Field 1995).

The 'advice' component of the dental recall examination is amenable to wide interpretation, but may be presumed to allude to professional advice directed towards the prevention of oral disease. Such advice may incorporate instruction on appropriate oral hygiene practices for the prevention of dental caries and periodontal disease (e.g. the use of fluoride toothpaste, appropriate toothbrushing techniques and other adjunctive methods of plaque control such as flossing), dietary advice (e.g. reducing the amount and frequency of intake of sugar containing foods and drinks) and advice aimed at modifying other risk factors for oral disease (e.g. the delivery of smoking cessation advice and alcohol reduction counselling).

The recall examination may therefore be construed as having a purported dual function as a primary and secondary preventive measure. The 'advice' component of the recall examination may be regarded as a primary preventive measure that seeks to influence patient behaviour with a view to preventing oral diseases before they occur. As a secondary preventive measure, a further aim of the check-up is to limit the progression and effect of oral diseases at as early a stage as possible after onset. This is achieved through the early detection of the signs and symptoms of oral diseases with a view to instituting clinical procedures and interventions which may have a favourable effect upon the natural history and clinical course of disease (Deep 2000).

Other functions that can be ascribed to the recall examination include the regular monitoring and preventive management of early carious lesions, the regular monitoring of stages of dental development to ensure that interventions are appropriate and timely (e.g. orthodontic treatment for malocclusions), the detection of the oral manifestations of systemic disease and appropriate referral for further investigation, the maintenance of dentist/patient rapport and the regular repetition and reinforcement of professional advice with a view to improving patient motivation and enhancing compliance with preventive recommendations. Recall examinations in the public dental services in some countries also regularly include specific preventive care such as the application of a fluoride gel or varnish (Wang 1995).

The provision of a scale and polish at a recall examination is also common practice in primary dental care settings (Elley 2001; Frame 2000; Jones 2013). Scaling can be defined as the mechanical removal of plaque, calcified deposits and staining from the crown and root surfaces of the teeth using manual or power-driven instrumentation or both. Polishing can be defined as the mechanical removal of any residual extrinsic stains and deposits that remain following the scaling procedure, using a rubber cup or bristle brush loaded with an abrasive or non-abrasive prophylaxis paste. In England, the traditional linking of the routine dental check-up and scale and polish treatments is reflected in NHS dental statistics which indicate that "half of all courses of dental treatment in England consist of consist of examination with or without diagnostic radiographs and scale and polish services" (Jones 2013).

A dental check-up may therefore be associated with a "package of dental services" for a number of oral diseases and conditions (Spencer 2009). The recall interval between check-ups influences the frequency with which these services are provided. In many countries a six-monthly recall interval has become an established practice and is commonly recommended by dental practitioners engaged in primary care (AAPD 2013; Anthonappa 2008; Clarkson 2009; Frame 2000; Gussy 2013; Kay 1999; Patel 2010; Scott 2002). However, the clinical and cost-effectiveness of six-monthly recall intervals have increasingly been questioned in light of recent changes in the epidemiology of dental diseases and in the interests of cost-containment and judicious use of scarce resources (Audit Commission 2002; DoH 2000; DoH 2002; HDA 2001; Sheiham 2000; Tan 2006).

How the intervention might work

The time period between dental check-ups may impact on oral health by influencing the periodicity of clinical examinations and any associated primary and secondary preventive measures. Short recall intervals (more frequent dental check-ups) may improve oral health by increasing the frequency with which the oral health of patients is reassessed and monitored and by allowing prompt preventive or therapeutic care to be delivered which may impact favourably on the clinical course of disease. However, short recall intervals may also increase the potential for iatrogenic overdiagnosis and overtreatment and may increase healthcare costs. In contrast, longer recall intervals may reduce iatrogenesis and short-term resource consumption but may also compromise oral health by reducing the frequency of the delivery of preventive advice and delaying the diagnosis of dental disease, thereby resulting in more extensive and costly care. In England it has also been argued that lengthening recall intervals for patients at low risk of or from dental disease "can allow NHS dentists and their teams to tackle health inequalities through having more time and resources to focus on providing access to new patients and prevention" (DoH 2011).

Why it is important to do this review

The optimal length of the recall interval (how often to attend for a dental check-up) for the preventive maintenance of oral health in both children and adults has been the subject of ongoing debate in many countries (Clarkson 2009; DTB 1985; Elderton 1985a; Elderton 1985b; Kay 1999; Lahti 2001; Lock 1986; Perlus 1994; Renson 1977; Renson 2000; Sheiham 1977; Sheiham 1980; Sheiham 2000). This debate has been fuelled by conflicting evidence from observational epidemiological studies on the beneficial and harmful effects of regular attendance and by diverging interpretations of that evidence. On the one hand, it has been reported that regular dental attendance is associated with improved oral health and that regular attenders have less untreated disease, lower rates of tooth loss, higher numbers of functioning teeth, and are less likely to suffer acute symptoms and to require emergency treatment (Murray 1996; Sheiham 1985; Todd 1991). An association between regular dental attendance and perception of how oral health affects quality of life has also been reported (McGrath 2001). In addition, it has been reported that regular attenders suffer significantly less from the severity, prevalence, social and psychological impacts of dental health problems (Richards 2002). On the other hand, it has also been argued that regular attenders do not experience any major advantage over irregular attenders in respect of their total disease experience and that regular visits do not help to prevent the onset of further disease (Sheiham 1985). Based on an analysis of the results of the 1998 Adult Dental Health Survey in the United Kingdom (Kelly 2000), Sheiham has argued that occasional attenders had less periodontal disease, more teeth present and fewer missing teeth than regular attenders (Sheiham 2000). Concerns have also been expressed about the financial implications for patients associated with regular attendance, including time foregone in attending for appointments, and the enhanced possibility for iatrogenic interventions associated with regular attendance (Reekie 1997; Sheiham 1985).

The debate over the relative merits and demerits of regular versus irregular attendance has been further complicated by contemporary changes in the epidemiology of dental diseases, in particular dental caries. Since the 1970s the prevalence and severity of dental caries in many developed countries has decreased dramatically and the rate of progression of the disease has slowed (Brown 1995; Mejare 1999 ; Mejare 2004; Pitts 1983). Caries experience in many contemporary populations also exhibits a skewed distribution with a majority of children and adolescents having little or no disease, whilst for a minority the caries experience remains relatively high (Hausen 1997). In particular, it has been consistently observed that caries experience is generally more extensive and severe in lower socioeconomic status groups (Burt 1999). These factors have led to suggestions in a number of countries that the notion of a 'fixed and universal' recall interval is inappropriate and that recall intervals should be patient specific (individualised) based on an assessment of the patient’s risk of or from oral disease (AAPD 2013; Clarkson 2009; Deep 2000; DoH 2000; HDA 2001; Lahti 2001; Perlus 1994; Riordan 1997).

The rationale underpinning the risk-based recall approach for the management of dental caries is that it should be possible to extend recall intervals for those individuals classified as 'low caries risk' without incurring any undue detrimental effect on their oral health status and ultimately reducing resource consumption. Relatively shorter recall intervals can then be adopted for those individuals with the greatest need who are classified as 'high caries risk'. Similarly, for periodontal disease it has been argued that recall intervals should be individualised and based on an evaluation of the patient's oral hygiene, disease activity, individual susceptibility and disease history (Brothwell 1998). In the UK, the justification for regular screening of all patients for oral cancer at six-monthly intervals has also been questioned on the grounds that the number of cases of oral malignancy is small and usually confined to patients at 'high risk' (due to tobacco use and excessive consumption of alcohol) over the age of 45 years (Sheiham 1977; Sheiham 1980).

Risk-assessment derived recall intervals for dental check-up examinations have recently been advocated by professional expert bodies and in clinical practice guidelines in several countries. For example, in the United States the American Academy of Pediatric Dentistry (AAPD) has stated that the periodicity of dental services should be based on a patient's individual needs and risk indicators and that some patients may require examination and preventive services at intervals more or less frequently than six months based upon historical, clinical and radiographic findings (AAPD 2013). In Western Australia the School Dental Service has adopted a practice of choosing recall intervals based on the clinician's assessment of a patient's risk of acquiring new disease (Lam 2012; Riordan 1997). In England and Wales the National Institute for Health and Care Excellence (NICE) have issued guidance recommending that the interval between oral health reviews "should be determined specifically for each patient and tailored to meet his or her needs, on the basis of an assessment of disease levels and risk of or from dental disease" (NICE 2004).

Although the concepts of assigning patient-specific and risk-based recall intervals have gained increasing currency, there remains significant variation in expert recommendations both within and between countries regarding the longest time interval between dental check-ups that can reasonably be assigned for patients who have been classified as 'low risk'. For example, the NICE guideline recommends that the longest interval between oral health reviews for patients younger than 18 years should be 12 months and that the interval should not exceed two years for older patients (NICE 2004). In contrast, Sheiham has argued that for low risk children (< 18 years of age) and adults in the UK the recall intervals should be 18 months and two to three years respectively (Sheiham 2000). Similarly, an expert group in Finland has recommended that recall intervals for low risk children and adolescents could be extended to 1.5 to two years without jeopardising their oral health (Lahti 2001).

The disparities in these recommendations can be partially explained by the absence of good quality, reliable evidence to inform clinical practice. Many guideline recommendations regarding the frequency of recall examinations have been informed primarily by professional consensus (Tomar 2011), and it is inevitable that expert opinions will vary when the available evidence is weak and conflicting. The poor quality of the evidence base pertaining to the effects on oral health of varying recall intervals between dental check-ups has been highlighted in previous versions of this review (Beirne 2005; Beirne 2007). It is important to continually update this review to incorporate any new evidence from randomised controlled trials that may be used to inform clinical practice guideline recommendations and that may facilitate clinical decision-making. This update has been carried to support UK National Guideline groups and US care providers, in response to requests for an up-to-date review of the latest evidence.

Objectives

(1) To determine the beneficial and harmful effects of different fixed recall intervals (for example six versus 12 months) for any one of the following different types of dental check-up:

  • clinical examination only

  • clinical examination plus scale and polish

  • clinical examination plus preventive advice

  • clinical examination plus preventive advice plus scale and polish.

(2) To determine the relative beneficial and harmful effects between any of the different check-ups listed above at the same fixed recall interval (for example 12 months).

(3) To compare the beneficial and harmful effects of recall intervals based on clinicians' assessments of patients' disease risk with fixed recall intervals. All methods used by clinicians to assess disease risk will be considered in relation to this objective (e.g. assessments based on patients' medical history, previous caries experience, dietary and oral hygiene practices, etc.).

(4) To compare the beneficial and harmful effects of no recall interval/patient driven attendance (which may be symptomatic) with fixed recall intervals.

Methods

Criteria for considering studies for this review

Types of studies

We included randomised controlled trials (RCTs) in this review.

Types of participants

We included all children and adults receiving dental check-ups in primary care settings, irrespective of their level of risk for oral disease.

Types of interventions

We considered recall intervals for:

  • clinical examination only;

  • clinical examination plus scale and polish;

  • clinical examination plus preventive advice;

  • clinical examination plus scale and polish plus preventive advice;

  • no recall interval/patient driven attendance (which may be symptomatic);

  • recall intervals based on clinician assessment of patient risk.

Types of outcome measures

Clinical status outcomes
  • Dental caries measured using any appropriate scale.

  • Periodontal disease measured using any appropriate scale.

  • Presence/absence of mucosal lesions, potentially malignant lesions, cancerous lesions.

  • Size and stage of cancerous lesions at diagnosis.

  • Dento-facial development.

Psychosocial (patient-centred) outcomes
  • Patient/parent satisfaction with provider of care (i.e. dentist, hygienist, therapist).

  • Patient/parent satisfaction with actual care received.

  • Patient oral comfort.

  • Patient/parent satisfaction with appearance.

  • Any assessment of patients' oral health related quality of life, provided this was recorded in a reproducible and validated format.

Economic costs
Costs to patient
  • Out of pocket payments for care received (patient charges) and insurance premiums.

  • Time and foregone wages or other opportunity costs.

  • Costs of transportation, child care expenses.

Costs to provider
  • Real costs of producing care for provider.

  • Dentist, hygienist, therapist time and other personnel time.

  • Materials, overheads, equipment used.

  • Costs to the healthcare system or third party provider were considered where reported.

Other outcomes
  • Improvements in oral health knowledge and attitudes, harms (such as fluorosis, overtreatment), changes in dietary habits and any other oral health related behavioural changes where reported.

Search methods for identification of studies

For the identification of studies included or considered for this review, we developed detailed search strategies for each database searched. These were based on the search strategy developed for MEDLINE (OVID) but revised appropriately for each database. The search strategy used a combination of controlled vocabulary and free text terms and was linked with the Cochrane Highly Sensitive Search Strategy (CHSSS) for identifying randomised trials (RCTs) in MEDLINE: sensitivity maximising version (2008 revision) as referenced in Chapter 6.4.11.1 and detailed in box 6.4.c of the Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011) (Higgins 2011). Details of the MEDLINE search are provided in Appendix 3. The search of EMBASE was linked to the Cochrane Oral Health Group filters for identifying RCTs.

Electronic searches

We searched the following electronic databases.

  • The Cochrane Oral Health Group's Trials Register (to 27 September 2013) (Appendix 1).

  • The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9) (Appendix 2).

  • MEDLINE via OVID (1946 to 27 September 2013) (Appendix 3).

  • EMBASE via OVID (1980 to 27 September) (Appendix 4).

No restrictions were placed on the language or date of publication when searching the electronic databases. Non-English language papers were translated.

Searching other resources

Ongoing trials

We searched the following resources for ongoing trials:

Handsearching

Only handsearching done as part of the Cochrane Worldwide Handsearching Programme and uploaded to CENTRAL was included (see the Cochrane Masterlist for details of journal issues searched to date).

The reference lists of all potentially eligible trials were checked for more relevant studies. Reference lists from review articles identified in the searches were also scanned for further studies.

Personal contact

The author(s) of eligible published studies and any researchers involved in the ongoing debate on recall intervals were contacted, where possible and when considered necessary, to obtain information on additional published or unpublished studies possibly eligible for inclusion.

Data collection and analysis

Selection of studies

Two review authors independently and in duplicate assessed the titles, keywords and abstracts (when available) of all reports identified by the search strategy as being of potential relevance to the review. The review authors remained unblinded regarding the author(s), their institutional affiliations and the site of publication of reports. The full report was obtained for all studies appearing to meet the inclusion criteria or in instances where there was insufficient information from the title, keywords and abstract to make a clear decision. Two review authors independently assessed all of the potentially relevant studies for eligibility. Instances of disagreement in the study selection process were referred to other members of the review team and ultimately resolved by mutual discussion among all review team members. We recorded studies rejected at this or subsequent stages in the Characteristics of excluded studies table, noting reasons for exclusion. All of the studies meeting the inclusion criteria were subjected to data extraction and risk of bias assessment.

Data extraction and management

Two review authors extracted data independently and in duplicate using specially designed and piloted data extraction forms. We presented the characteristics of the trial participants (including demographic characteristics and criteria for inclusion, different baseline prevalence of disease), sample size, numbers of participants randomised to each group, provider characteristics (dentist, hygienist, dental therapist), differences in diagnostic criteria and diagnostic thresholds used, interventions and outcomes for the included studies, direct and indirect costs (where provided) in the Characteristics of included studies table. Descriptive data extracted from the included study included the date of publication, the country/place of origin and study duration. Disagreements on data extraction were resolved by discussion among all of the review team members.

Assessment of risk of bias in included studies

Two review authors assessed the risk of bias in the included study, independently and in duplicate, using The Cochrane Collaboration risk of bias tool described in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). For each domain of risk of bias, we first described what was reported to have happened in the study in order to provide a rationale for the second part, which involved assigning a judgement of 'low risk' of bias, 'high risk' of bias, or 'unclear risk' of bias.

We assessed the following seven domains of risk of bias.

  • Random sequence generation (selection bias).

  • Allocation concealment (selection bias).

  • Blinding of participants and personnel (performance bias).

  • Blinding of outcome assessment (detection bias).

  • Incomplete outcome data (attrition bias).

  • Selective reporting (reporting bias).

  • Other bias (any other potential source of bias that may feasibly alter the magnitude of the effect estimate).

We summarised the risk of bias as follows.

Risk of biasInterpretationIn outcomeIn included studies
Low risk of biasPlausible bias unlikely to seriously alter the resultsLow risk of bias for all key domainsMost information is from studies at low risk of bias
Unclear risk of biasPlausible bias that raises some doubt about the resultsUnclear risk of bias for one or more key domainsMost information is from studies at low or unclear risk of bias
High risk of biasPlausible bias that seriously weakens confidence in the resultsHigh risk of bias for one or more key domainsThe proportion of information from studies at high risk of bias is sufficient to affect the interpretation of results

Measures of treatment effect

For continuous outcomes (e.g. caries - decayed, missing, filled surfaces), we used the mean values and standard deviations reported in the study in order to express the estimate of effect of the intervention as mean difference (MD) with 95% confidence interval (CI). If different scales were used, we would have expressed the treatment effect as standardised mean difference (SMD) and 95% CI.

For dichotomous outcomes (e.g. presence/absence of mucosal lesions), we would have expressed the estimate of effect of the intervention as a risk ratio (RR) with 95% CI.

Unit of analysis issues

The participant was the unit of analysis. Any cluster-RCTs would need to have analysed results taking account of the clustering present in the data, otherwise we would have used the methods outlined in Section 16.3.4 of the Cochrane Handbook for Systematic Reviews of Interventions in order to perform an approximately correct analysis (Higgins 2011).

Dealing with missing data

We contacted the author of the included study to attempt to clarify risk of bias issues. Where appropriate, we would have used the methods outlined in Section 7.7.3 of the Cochrane Handbook for Systematic Reviews of Interventions in order to estimate missing standard deviations (Higgins 2011). We did not use any further statistical methods or carry out any further imputation to account for missing data.

Assessment of heterogeneity

If meta-analyses had been performed, we would have assessed the possible presence of heterogeneity by visual inspection of the point estimates and CIs on the forest plots; if the CIs had poor overlap then heterogeneity would be considered to be present. We would also assess heterogeneity statistically using a Chi2 test, where a P value < 0.1 indicates statistically significant heterogeneity. Furthermore, we would quantify heterogeneity using the I2 statistic. A guide to interpretation of the I2 statistic given in Section 9.5.2 of the Cochrane Handbook for Systematic Reviews of Interventions is as follows (Higgins 2011):

  • 0% to 40%: might not be important;

  • 30% to 60%: may represent moderate heterogeneity;

  • 50% to 90%: may represent substantial heterogeneity;

  • 75% to 100%: considerable heterogeneity.

Assessment of reporting biases

If there had been more than 10 studies in a meta-analysis, we would have assessed possible publication bias by visually inspecting a funnel plot for asymmetry. If detected, we would have carried out further investigation using the methods described by Egger 1997 for continuous outcomes and Rücker 2008 for dichotomous outcomes.

Data synthesis

We would only have carried out a meta-analysis where studies of similar comparisons reported the same outcomes. We would have combined MDs (standardised mean differences where studies had used different scales) for continuous outcomes, and would have combined RRs for dichotomous outcomes, using a fixed-effect model if there were less than four studies, or a random-effects model if there were at least four studies.

Subgroup analysis and investigation of heterogeneity

If there were sufficient numbers of studies, we planned to conduct subgroup analyses, where possible, according to age and for participants at different levels of risk for oral disease.

Sensitivity analysis

If there were sufficient numbers of studies, we planned to conduct sensitivity analyses by excluding studies at high and unclear risk of bias from the meta-analyses.

Summary of findings table

We produced a summary of findings table for main outcomes of this review using GRADEPro software. We assessed the quality of the body of evidence by considering the overall risk of bias of the included studies, the directness of the evidence, the inconsistency of the results, the precision of the estimates, the risk of publication bias, and the magnitude of the effect. We categorised the quality of the body of evidence for each of the primary outcomes as high, moderate, low or very low.

Results

Description of studies

Results of the search

The searches yielded 1293 references and, following de-duplication, this number was reduced to 762 references. Two review authors screened the titles and abstracts against the inclusion criteria for this review, independently and in duplicate, discarding 758 references in the process. We obtained full-text copies of three references (the remaining record was a reference to an ongoing study) and examined them independently and in duplicate, excluding two of them. Therefore, one study met the inclusion criteria for this review. We present the study flow process diagrammatically in Figure 1.

Figure 1.

Study flow diagram.

Included studies

Characteristics of the trial designs and settings

One study was included in this review (Wang 1992) (Characteristics of included studies table). The study was conducted in a public dental clinic in Tromso, Norway. One dentist and one dental hygienist provided all dental care over the two years of the trial. There were three different age groups included in this trial (three, 16 and 18 year olds). The hygienist examined three-year old participants in the trial at the initial, at the intermediate and at the last visits. The dentist examined 16 and 18-year olds and provided operative treatment for all the children.

Characteristics of the participants

The participants in this study were aged either three, 16 or 18 years at entry into the trial (aged five, 18 and 20 years at completion of the trial) and all had previously received regular dental care, including preventive services and health promotion. Children classified as 'risk' patients were not included in the study. The criteria used for the classification of risk patients were:

  • three-year olds (more than zero dmft);

  • 16-year olds (at least one decayed surface and four or more initial carious lesions and more than 10 DMFT);

  • 18-year olds (at least one decayed surface and four or more initial carious lesions and more than 12 DMFT).

Characteristics of the interventions
Clinical examination compared with clinical examination at a different recall interval

The participating children in this study were randomly allocated to two groups. One group was recalled for examination after 12 and 24 months (12-month recall group) and the other group was recalled after 24 months (24-month recall group).

Characteristics of the outcomes
Characteristics of the outcome measures (and time points when measured)

In this study, the incremental number of decayed, missing, filled and sound tooth surfaces (DMFS) were recorded from baseline examination to 24 months. Primary teeth were recorded in the three to five-year age group and permanent teeth in the 16 to 18 and 18 to 20-year age groups. We combined the data for the latter two age groups. A tooth surface was recorded as decayed if the carious process extended into the dentine as assessed clinically and radiographically.

Time in minutes used for each patient was recorded in four categories: clinical examination, operative treatment, acute visits (unscheduled extra visits initiated by the patient) and minutes wasted when the patient did not show up. All time values were rounded up to the nearest five minutes. All of these categories were added together to give the 'total time'.

No patient-centred outcomes were reported in the included study.

Excluded studies

We excluded two studies from this review (Grimm 1986; Schulz 1989) (Characteristics of excluded studies table). Both studies were both reported in German and, after obtaining translations, it was clear that one study was not an RCT (Grimm 1986), whilst it was not clear whether or not the other study was an RCT (Schulz 1989), and we were unable to contact the authors.

Risk of bias in included studies

We assessed the risk of bias of the one included study (Wang 1992). The main author of the study was contacted to provide additional information for our quality assessment. Unfortunately, the required information was no longer available.

Allocation

The method of sequence generation was not described and allocation concealment was not mentioned. Therefore, we assessed the study as being at unclear risk of selection bias.

Blinding

It was not possible to blind participants to their allocated group, whilst blinding of personnel was not mentioned. As one dentist and one dental hygienist provided all dental care and examined all the participants it is possible that they could be aware of the participant's allocated group when assessing the outcomes. Therefore we assessed the study as being at high risk of performance and detection bias.

Incomplete outcome data

Attrition was equal across treatment groups (22% from the 12-month group and 24% from the 24-month group) and, in all cases, was due to participants leaving the area. Therefore we assessed the study as being at low risk of attrition bias.

Selective reporting

Outcomes stated in the methods section were reported in full and therefore we assessed the study as being at low risk of outcome reporting bias.

Other potential sources of bias

We did not detect any other possible biases and therefore assessed the study as being at low risk of bias for this domain.

Overall risk of bias

The single included study in this review was judged to be at high risk of bias overall (Wang 1992). The risk of bias across the seven domains assessed is presented graphically in Figure 2.

Figure 2.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Effects of interventions

See: Summary of findings for the main comparison Clinical examination at 12 months versus clinical examination at 24 months

Comparison 1: Clinical examination versus clinical examination at a different interval

One study, analysing 185 participants and at high risk of bias, provided data for this comparison of 12-month versus 24-month recall for the outcomes caries (dmfs/DMFS increment) and total time (examination plus treatment time) (Wang 1992).

Caries (dmfs/DMFS increment)

Analysis 1.1.

For three to five-year olds with primary teeth, the mean difference (MD) in dmfs increment was -0.90 (95% confidence interval (CI) -1.96 to 0.16) in favour of 12-month recall. For 16 to 20-year olds with permanent teeth, the MD in DMFS increment was -0.86 (95% CI -1.75 to 0.03) also in favour of 12-month recall. As this was a single study at high risk of bias, and it was unclear whether or not the sample size was sufficient to detect a difference, there is insufficient evidence to determine whether 12 or 24-month recall with clinical examination results in better caries outcomes.

Total time (minutes)

Analysis 1.2.

For three to five-year olds with primary teeth, the MD in time used by each participant was 10 minutes (95% CI -6.7 to 26.7) in favour of 24-month recall. For 16 to 20-year olds with permanent teeth, the MD was 23.7 minutes (95% CI 4.12 to 43.28) also in favour of 24-month recall. This single study at high risk of bias represents insufficient evidence to determine whether 12 or 24-month recall with clinical examination results in better time/cost outcomes.

We did not identify any other studies reporting the other comparisons or outcomes relevant to this review.

Discussion

Summary of main results

We included one study which compared the effects of a clinical examination every 12 months with a clinical examination every 24 months on the outcomes of caries and time used per participant. We assessed the body of evidence using GRADE (GRADE 2004), which incorporates risk of bias of any included studies, the directness of the evidence, the inconsistency of the results, the precision of the estimates and the risk of publication bias (Summary of findings for the main comparison). We assessed the body of evidence, from one study analysing 185 participants with two-year follow-up, as being very low quality for caries and time outcomes, and for both primary and permanent teeth. We considered the available evidence insufficient to conclude whether or not there is a difference in these outcomes for primary or permanent teeth when varying the recall interval for a clinical examination.

Overall completeness and applicability of evidence

The debate over appropriate recall intervals between dental check-ups for primary care patients was first initiated over three decades ago (Sheiham 1977). Given the longevity of this debate and the potential impact of altering recall intervals on healthcare costs and outcomes and provider workloads, it is disappointing that there is a paucity of good quality and reliable research evidence that can be used to inform clinical practice. Only one randomised controlled trial satisfied the eligibility criteria for this review. This trial was judged to be at high risk of bias and hence the results presented therein should be interpreted cautiously. In addition, the study was carried out on low risk patients in the public dental services in Norway who had previously received regular dental care, including health promotion and preventive services; hence the extent to which the results of this study can be extrapolated and applied to different populations (with different baseline risk) and in different settings is unclear. No statistically significant differences in oral health (measured using dmfs/DMFS increments) were reported between 12-month and 24-month recall groups for both age groups (three to five years representing primary teeth and 16 to 20 years representing permanent teeth) in this single study. The total time taken per person was significantly shorter in the 24-month recall group compared with the 12-month group in the older age group but the limited quantity and quality of the evidence available from this one study preclude drawing any conclusions regarding the effects on oral health and the economic impact of altering recall intervals between dental check-ups.

Quality of the evidence

The body of evidence is insufficient to address the objectives of this review. We downgraded the quality of the body of evidence due to there being a single study which was at high risk of performance and detection bias, resulting from a lack of blinding. The method of sequence generation was also unclear and allocation concealment was not mentioned at all. The evidence was further downgraded due to low sample size, resulting in imprecision, and due to indirectness of the evidence, resulting from the fact that only low risk patients were included. This population had also previously received regular dental care, including health promotion and preventive services. This means that those making recommendations on optimal recall intervals may not find the evidence currently in this review applicable to their setting.

Potential biases in the review process

We have attempted to limit potential biases in the review process in several ways. We have tried to identify all relevant studies through sensitive searching of multiple databases, with no restriction on language or publication status. We attempted to contact study authors for clarification on eligibility or risk of bias issues. Finally, two authors carried out screening of search results, data extraction and risk of bias assessment independently and duplicate.

Agreements and disagreements with other studies or reviews

We are aware of three systematic reviews that have evaluated the effectiveness of routine dental check-ups of different recall intervals.

(1) A review that was carried out as part of the National Health Service (NHS) Research and Dissemination Health Technology Assessment (HTA) Programme in the UK (Davenport 2003) (the date of the last search carried out for this HTA review was February 2001).

(2) An update of this HTA review that was undertaken as part of the guideline development process for a National Institute for Health and Care Excellence guideline on appropriate recall intervals between dental check-ups (NICE 2004) (the date of the last search carried out for the 'updated' review was July 2003).

(3) A review that evaluated the effect of recall intervals on dental caries only (Patel 2010) (the date of the last search for this review was September 2008).

The selection criteria for these reviews differed from our review, most notably because they included non-randomised studies. In our review we excluded all study designs lacking the experimental element of random allocation of participants to an intervention, due to the susceptibility of such studies to selection biases and confounding. Bias and confounding are likely to be particularly problematic in non-randomised studies that involve making comparisons between the oral health status of 'regular' and 'irregular' attenders. Frequent attendance may simply be a marker for generally healthy behaviour and differences in general health behaviour may explain the different patterns in oral health between the comparison groups. Whilst statistical techniques can be used to adjust for known confounding factors in non-randomised studies, by definition, unknown confounders can only be balanced through randomisation. We therefore have some reservations regarding the merit of including non-randomised studies in systematic reviews evaluating the effects of varying recall intervals between dental check-ups. Nevertheless, we have summarised the findings of these reviews below.

(1) The authors of the HTA review (Davenport 2003) identified 28 studies for inclusion in their review. Many of the studies were poorly reported and methodologically and clinically heterogenous with inadequate description of patient and intervention (dental check-up) characteristics, thus limiting comparison between studies. In addition, there was a preponderance of cross-sectional studies included in the review, which are particularly prone to selection biases and confounding. There was no consistency across studies in the direction of effect of different dental check frequencies on measures of caries, periodontal disease or oral cancer. The review authors concluded that there was no high quality evidence to support or refute the practice of encouraging six-monthly dental checks in children and adults and that there was little evidence to suggest an optimal dental check frequency for any of the outcomes considered. The authors recommended that the quality of design and reporting of future research should be improved and that increased emphasis should be placed on patient-centred oral health outcomes.

(2) Thirteen additional observational epidemiological studies were identified in the update of the HTA review (NICE 2004). All studies were judged during the quality assessment process as having some threat to validity. A major limitation of the included studies was the method used to measure the frequency of the intervention (dental check-up). The majority of studies used a subjective measure of dental check frequency and relied on participants' reported attendance, obtained from self administered questionnaires or structured interviews. This may have compromised the validity of the data collected as it is reasonable to assume that attendance frequency is 'over estimated' in questionnaire/interview type surveys and there is some empirical evidence to support this assumption (Elderton 1983). A further limitation of the included studies related to the comparisons made. The most common comparison was between the oral health status of 'regular' and 'irregular' attenders. However, different studies used completely different definitions of what constituted 'regular' and 'irregular' attendance which imposed serious limitations on the inferences that could be drawn from this evidence. For example, in one study (Bullock 2001) a regular attender was defined as someone who attended for at least two dental examinations in the past two years. However, in another study (Richards 2002) a regular attender was defined as someone whose last attendance was within the last two years. A further problem with many of these non-randomised studies was the inability to distinguish between prevention oriented/motivated visits (for asymptomatic check-up) and treatment oriented/motivated visits for a specific problem such as infection, restoration failure or other clinical problems.

The review authors concluded that: a) the results of the updated review had no impact on the conclusions of the original HTA review; b) there was a paucity of evidence with which to inform clinical practice on assigning recall intervals; and c) further research was needed to examine the effects of varying dental recall intervals on oral health. In developing their recommendations, the guideline developers used evidence pertaining to risk factors for oral diseases and formal consensus methods and recommended that the recall interval between dental check-ups should be based on the clinician's professional assessment of a patient's risk of or from oral disease. The guideline recommends that this assessment should take into account the patient's medical history, social history, behavioural risk factors for oral disease and past and current disease levels. The full text of the 'Dental recall' guideline can be accessed through the NICE website (www.nice.org.uk).

This NICE guideline was formally reviewed in 2008 (four-year review) and in 2012 (eight-year review). On both occasions it was recommended that the guideline should not be updated on the grounds that there was insufficient new evidence available to invalidate the current guideline recommendations.

(3) The authors of the review evaluating the effects of recall intervals on dental caries (Patel 2010) identified one randomised trial (this trial was also included in our review), two prospective non-randomised controlled trials, two retrospective chart reviews and one cross-sectional study that met the selection criteria. All studies were judged to be methodologically weak and the evidence was deemed insufficient "to support using any specific one-recall-interval-fits-all protocol for all patients" (Patel 2010).

The findings of these reviews are therefore generally consistent with our review and point towards the urgent need for high quality research to address the uncertainty over the effects of altering recall intervals between dental check-ups. There is currently one multicentre, parallel-group randomised controlled trial in progress in the UK (the 'INTERVAL Dental Recalls Trial') (ISRCTN95933794). The trial is due to be completed in 2017 and we will incorporate the results of this trial in future updates of our review. The trial is investigating whether risk-based recall intervals or a fixed-period 24-month recall are more effective and cost-effective in maintaining oral health than the traditional fixed-period six-monthly recall. We have provided additional details of this trial in the Characteristics of ongoing studies section of this review.

Authors' conclusions

Implications for practice

There is a very low quality body of evidence from one randomised controlled trial which is insufficient to reach any conclusions regarding the potential beneficial and harmful effects of varying recall intervals between dental check-ups. There is no evidence to support or refute the practice of encouraging patients to attend for dental check-ups at six-monthly intervals.

Implications for research

There is a need for well conducted randomised controlled trials in this area which include a sufficient number of participants to detect a true difference, if any, and that are of sufficient duration. The types of outcome measures used in these studies should include the clinical measures we have identified in this review (Types of outcome measures) as well as patient-centred factors and economic factors. The studies should also specify explicitly what the dental check-up actually entails (e.g. a clinical examination only or a clinical examination plus preventive advice) (Types of interventions). Furthermore, the precise nature and content of the preventive advice delivered as part of the dental check-up should be clearly specified. All trials should be reported according to the Consolidated Standards of Reporting of Trials (CONSORT) guidelines (www.consort-statement.org/).

Acknowledgements

We would like to thank and acknowledge the help of Andrew Forgie in writing the protocol and deciding which studies should be included in the review. We wish to thank Sylvia Bickley for her assistance with literature searching in previous versions of the review, Anne Littlewood (Cochrane Oral Health Group) for redesigning and carrying out the searches for this version; Emma Tavender and Luisa Fernandez Mauleffinch (Cochrane Oral Health Group) for their help with the preparation of this review; Regina Mitezki for translating three German articles; Nina Wang, Lowell Smith, Ram Nanda and Jan Lindhe for responding to requests for information on specific trials. The review authors are also grateful for the comments of members of the Guideline Development Group on recall intervals between routine dental examinations conducted under the auspices of the National Institute for Health and Care Excellence (NICE) and co-ordinated by the National Collaborating Centre for Acute Care (NCC-AC). In particular the review authors would like to thank Jacqueline Dutchak and Nigel Pitts.

Data and analyses

Download statistical data

Comparison 1. Clinical examination at 12 months versus clinical examination at 24 months
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Caries (dmfs/DMFS increment)1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
1.1 3-5 year olds (primary teeth)1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
1.2 16-20 year olds (permanent teeth)1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
2 Total time (minutes)1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
2.1 3-5 year olds (primary teeth)1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
2.2 16-20 year olds (permanent teeth)1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
Analysis 1.1.

Comparison 1 Clinical examination at 12 months versus clinical examination at 24 months, Outcome 1 Caries (dmfs/DMFS increment).

Analysis 1.2.

Comparison 1 Clinical examination at 12 months versus clinical examination at 24 months, Outcome 2 Total time (minutes).

Appendices

Appendix 1. Cochrane Oral Health Group's Trials Register search strategy

1 ((“routine check up” or “routine inspect*” or “routine appointment*” or “routine examin*” or “routine attend*” or “ routine recall” or “routine visit*”):ti,ab) AND (INREGISTER)
2 ((“regular check up” or “regular inspect*” or “regular appointment*” or “regular examin*” or “regular attend*” or “ regular recall” or “regular visit*”):ti,ab) AND (INREGISTER)
3 ((“periodic check up” or “periodic inspect*” or “periodic appointment*” or “periodic examin*” or “periodic attend*” or “ periodic recall” or “periodic visit*”):ti,ab) AND (INREGISTER)
4 ((“six month check up” or “six month inspect*” or “six month appointment*” or “six month examin*” or “six month attend*” or “ six month recall” or “six month visit*”):ti,ab) AND (INREGISTER)
5 ((“6 month check up” or “6 month inspect*” or “6 month appointment*” or “6 month examin*” or “6 month attend*” or “6 month recall” or “6 month visit*”):ti,ab) AND (INREGISTER)
6 ((“three month check up” or “three month inspect*” or “three month appointment*” or “three month examin*” or “three month attend*” or “three month recall” or “three month visit*”):ti,ab) AND (INREGISTER)
7 ((“3 month check up” or “3 month inspect*” or “3 month appointment*” or “3 month examin*” or “3 month attend*” or “3 month recall” or “3 month visit*”):ti,ab) AND (INREGISTER)
8 ((“nine month check up” or “nine month inspect*” or “nine month appointment*” or “nine month examin*” or “nine month attend*” or “nine month recall” or “nine month visit*”):ti,ab) AND (INREGISTER)
9 ((“9 month check up” or “9 month inspect*” or “9 month appointment*” or “9 month examin*” or “9 month attend*” or “9 month recall” or “9 month visit*”):ti,ab) AND (INREGISTER)
10 ((“twelve month check up” or “twelve month inspect*” or “twelve month appointment*” or “twelve month examin*” or “twelve month attend*” or “twelve month recall” or “twelve month visit*”):ti,ab) AND (INREGISTER)
11 ((“12 month check up” or “12 month inspect*” or “12 month appointment*” or “12 month examin*” or “12 month attend*” or “12 month recall” or “12 month visit*”):ti,ab) AND (INREGISTER)
12 ((recall and interval):ti,ab) AND (INREGISTER)
13 (#1 or #2 or #3 or #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12) AND (INREGISTER)

Appendix 2. CENTRAL search strategy

#1 [mh "Stomatognathic diseases"]
#2 [mh Dentistry]
#3 [mh ^"Oral health"]
#4 [mh ^"Dentists practice patterns"]
#5 "oral health"
#6 (tooth or teeth or dental or dentist)
#7 {or #1-#6}
#8 [mh ^"Appointments and schedules"]
#9 (routine* near/5 ("check up" or inspect* or appointment* or examin* or attend* or recall* or visit*))
#10 (regular* near/5 ("check up" or inspect* or appointment* or examin* or attend* or recall* or visit*))
#11 (periodic* near/5 ("check up" or inspect* or appointment* or examin* or attend* or recall* or visit*))
#12 (("six month*" or six-month* or three-month* or "three month*" or nine-month* or "nine month*" or "twelve month*" or twelve-month* or "6 month*" or "3 month*" or "9 month*" or "12 month*") next ("check up" or inspect* or appointment* or examin* or attend* or recall* or visit*))
#13 (recall* near/3 interval*)
#14 {or #8-#13}
#15 #7 and #14

Appendix 3. MEDLINE (OVID) search strategy

1. exp Stomatognathic diseases/
2. exp Dentistry/
3. Oral health/
4. Dentists practice patterns/
5. "oral health".ti,ab.
6. (tooth or teeth or dental or dentist).ti,ab.
7. or/1-6
8. "Appointments and schedules"/
9. (routine$ adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
10. (regular adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
11. (periodic adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
12. (("six month$" or six-month$ or three-month$ or "three month$" or nine-month$ or "nine month$" or "twelve month$" or twelve-month$ or "6 month$" or "3 month$" or "9 month$" or "12 month$") adj ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
13. (recall$ adj3 interval$).ti,ab.
14. or/8-13
15. 7 and 14

The above subject search was linked to the Cochrane Highly Sensitive Search Strategy (CHSSS) for identifying randomised trials in MEDLINE: sensitivity maximising version (2008 revision) as referenced in Chapter 6.4.11.1 and detailed in box 6.4.c of theCochrane Handbook for Systematic Reviews of Interventions, Version 5.1.0 [updated March 2011] (Higgins 2011).

1. randomized controlled trial.pt.
2. controlled clinical trial.pt.
3. randomized.ab.
4. placebo.ab.
5. drug therapy.fs.
6. randomly.ab.
7. trial.ab.
8. groups.ab.
9. or/1-8
10. exp animals/ not humans.sh.
11. 9 not 10

Appendix 4. EMBASE (OVID) search strategy

1. exp Mouth disease/
2. exp Dentistry/
3. "oral health".ti,ab.
4. (tooth or teeth or dental or dentist).ti,ab.
5. or/1-4
6. (routine$ adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
7. (regular adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
8. (periodic adj5 ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
9. (("six month$" or six-month$ or three-month$ or "three month$" or nine-month$ or "nine month$" or "twelve month$" or twelve-month$ or "6 month$" or "3 month$" or "9 month$" or "12 month$") adj ("check up" or inspect$ or appointment$ or examin$ or attend$ or recall$ or visit$)).ti,ab.
10. (recall$ adj3 interval$).ti,ab.
11. or/6-10
12. 5 and 11

The above subject search was linked to the Cochrane Oral Health Group filter for identifying RCTs in EMBASE via OVID:

1. random$.ti,ab.
2. factorial$.ti,ab.
3. (crossover$ or cross over$ or cross-over$).ti,ab.
4. placebo$.ti,ab.
5. (doubl$ adj blind$).ti,ab.
6. (singl$ adj blind$).ti,ab.
7. assign$.ti,ab.
8. allocat$.ti,ab.
9. volunteer$.ti,ab.
10. CROSSOVER PROCEDURE.sh.
11. DOUBLE-BLIND PROCEDURE.sh.
12. RANDOMIZED CONTROLLED TRIAL.sh.
13. SINGLE BLIND PROCEDURE.sh.
14. or/1-13
15. (exp animal/ or animal.hw. or nonhuman/) not (exp human/ or human cell/ or (human or humans).ti.)
16. 14 NOT 15

Appendix 5. US National Institutes of Health Trials Register (ClinicalTrials.gov) search strategy

recall and (dental or dentist)

Appendix 6. WHO International Clinical Trials Registry Platform search strategy

recall and dental or recall and dentist or recall and dentistry

What's new

Last assessed as up-to-date: 27 September 2013.

DateEventDescription
15 December 2013New citation required but conclusions have not changedBackground, methods and discussion updated, risk of bias assessment of included study carried out, changes to the way the data are presented, summary of findings table added, ongoing study added, no new included studies
15 December 2013New search has been performedSearches updated to 27 September 2013

History

Protocol first published: Issue 3, 2003
Review first published: Issue 2, 2005

DateEventDescription
19 June 2008AmendedConverted to new review format
10 August 2007New citation required but conclusions have not changedUpdated search. Change in authors

Contributions of authors

  • Writing the protocol: Paul Beirne (PB), Andrew Forgie (AF), Helen Worthington (HW), Jan Clarkson (JC).

  • Screening studies for eligibility: PB, AF, Philip Riley (PR).

  • Risk of bias assessment: PB, HW, PR.

  • Data extraction and analysis: all authors.

  • Writing the review: all authors.

Declarations of interest

None of the review authors have any interests to declare.

Sources of support

Internal sources

  • School of Dentistry, The University of Manchester, UK.

  • Scottish Executive, UK.

  • University College Cork, Ireland.

  • MAHSC, UK.

    The Cochrane Oral Health Group is supported by the Manchester Academic Health Sciences Centre (MAHSC) and the NIHR Manchester Biomedical Research Centre.

External sources

  • Cochrane Fellowship - Health Research Board, Ireland.

  • Department of Health Cochrane Review Incentive Scheme, UK.

  • National Institute for Health Research (NIHR), UK.

    CRG funding acknowledgement:
    The NIHR is the largest single funder of the Cochrane Oral Health Group.

    Disclaimer:
    The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR, NHS or the Department of Health.

  • Cochrane Oral Health Group Global Alliance, UK.

    All reviews in the Cochrane Oral Health Group are supported by Global Alliance member organisations (British Association of Oral Surgeons, UK; British Orthodontic Society, UK; British Society of Paediatric Dentistry, UK; British Society of Periodontology, UK; Canadian Dental Hygienists Association, Canada; National Center for Dental Hygiene Research & Practice, USA; Mayo Clinic, USA; New York University College of Dentistry, USA; and Royal College of Surgeons of Edinburgh, UK) providing funding for the editorial process (http://ohg.cochrane.org/).

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Wang 1992

  1. a

    DMFS = decayed, missing, filled surfaces; DMFT/dmft = decayed, missing, filled teeth; RCT = randomised controlled trial; SD = standard deviation

Methods

Trial design: parallel-group RCT (2 arms)
Location: public dental clinic, Tromsø, Norway

Number of centres: 1

Participants

Inclusion criteria: children and adolescents who received regular dental care in one public dental clinic in Norway; participants entering the trial were either 3, 16 or 18 years of age

Exclusion criteria: children classified as 'at risk'. Criteria for classification of 'risk patients':
3 years: more than 0 dmft
16 years: at least 1 decayed surface and 4 or more initial carious lesions and more than 10 DMFT
18 years: at least 1 decayed surface and 4 or more initial carious lesions and more than 12 DMFT

Baseline caries (DMFS) (mean and SD): 3-year olds (12-month group: 0 ± 0; 24-month group: 0 ± 0); 16-year olds (12-month group: 10.6 ± 7.7; 24-month group: 11.4 ± 5.7); 18-year olds (12-month group: 11.9 ± 6.7; 24-month group: 13.7 ± 6.8)

Age at baseline: stratified into 3-, 16-, and 18-year olds

Gender: not reported

Number randomised: 241; 3-year olds (12-month group: 35; 24-month group: 35); 16-year olds (12-month group: 50; 24-month group: 51); 18-year olds (12-month group: 35; 24-month group: 35)

Number evaluated: 185; 3-year olds (12-month group: 27; 24-month group: 31); 16-year olds (12-month group: 43; 24-month group: 35); 18-year olds (12-month group: 23; 24-month group: 26)

Interventions

Comparison: 12-month recall versus 24-month recall

1 dentist and 1 hygienist provided all dental care. The hygienist examined 3-year old patients at the initial, intermediate and final visits. The dentist examined the 16 and 18-year olds and provided operative treatment for all the children

Duration of study: 24 months

OutcomesDMFS increment; total time (the sum of clinical examination time, operative treatment, acute visits (unscheduled extra visits initiated by the participant) and minutes wasted when the participant did not show up)
Notes

Funding source: not reported

Sample size calculation: not reported

Adverse effects: not reported

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear risk

Quote: "The participating children were randomly allocated to two groups"

Comment: insufficient information

Allocation concealment (selection bias)Unclear risk

Quote: "The participating children were randomly allocated to two groups"

Comment: insufficient information

Blinding of participants and personnel (performance bias)
All outcomes
High riskBlinding of participants was not possible. Blinding of personnel was not mentioned
Blinding of outcome assessment (detection bias)
All outcomes
High risk1 dentist and 1 dental hygienist provided all dental care and examined the participants. Therefore blinding of outcome assessment was not carried out
Incomplete outcome data (attrition bias)
All outcomes
Low risk22% dropped out from the 12-month group; 24% dropped out from the 24-month group; all drop-outs were due to leaving the area
Selective reporting (reporting bias)Low riskOutcomes stated in the methods section were reported in full
Other biasLow riskNo other apparent biases

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Grimm 1986Not a randomised controlled trial. In this study treatment and control groups were formed according to the age of participants
Schulz 1989Unable to contact authors to determine if this study was a randomised controlled trial (paper in German)
This study was fully translated with a view to determining its eligibility. However, we were unable to ascertain from this translation if it was a randomised trial. In addition the interventions and comparison groups were poorly described. The authors state that "55 test persons participated in this study. They had gingivitis caused by plaque at the age 15 and 25 years (17.7 years on average). Not included were pregnant women, patients with internal diseases, with prosthetic restorations and untreated caries. 15 test persons took part in 3 different programmes, over a period of 3 months that had the following objectives: oral hygiene instructions and motivation (dental nurse) as well as professional tooth cleaning (dentist). 1 group made up of 10 test persons (group IV) served as the control group. The programme of group III with 1 motivation session without teeth cleaning training was designed to check which results the frequent examination with an oral hygiene pass/check book produces. From the results of the test group we expected indications of the motivating effect of the professional teeth cleaning and of the importance for the reduction of gingivitis as such"

Characteristics of ongoing studies [ordered by study ID]

ISRCTN95933794

Trial name or titleINTERVAL Dental Recalls Trial
MethodsMulticentre, 3-arm, parallel-group, randomised controlled trial
ParticipantsAdult patients (18 years of age or older) in the United Kingdom, who are dentate, have visited their dentist in the previous 2 years, and receive all or part of their dental care as an National Health Service patient
Interventions6-month fixed-period recall versus risk-based recall versus 24-month fixed-period recall
Outcomes

Primary

1. Health-related quality of life measured using an annual, self administered patient questionnaire. Questionnaire will include a global assessment of quality of life using short form Oral Health Impact Profile, a standardised measure of health outcome (EQ-5D) and a specially developed, context-specific, health-related quality of life measure
2. Periodontal disease assessed by gingival inflammation/bleeding measured according to the Gingival Index of Loe

Secondary
1. Caries experience assessed at both the enamel and dentine thresholds using the validated International Caries Detection and Assessment System (ICDAS). The ICDAS criteria measure both early and more advanced stages of caries. For early caries, ICDAS measures the surface changes and potential histological depth of carious lesions by relying on surface characteristics related to the optical properties of sound and demineralised enamel prior to cavitation. All surfaces of all teeth will be examined and the status of each recorded in terms of caries and restorations. This system allows the recording of both preventive and operative care needs
2. Plaque measured according to the Silness and Loe Plaque Index, calculus measured according to the Ramfjord Calculus Index and a colour-coded UNC periodontal probe will be used to measure periodontal pocket depth and clinical attachment level. The assessments will be made at 4 years by trained examiners who are blinded to allocation
3. Patient-centred outcomes including dental anxiety, oral health related knowledge, attitudes, and behaviours, use of and reason for use of dental services (including symptoms and pain), and satisfaction with care measured using annual, self administered questionnaire. Total duration of follow-up: 4 years
4. Dentist attitude towards the different recall strategies measured using a self administered questionnaire at month 0 and at 4 years

All clinical outcomes are measured at 4 years by trained examiners who are blinded to allocation

Starting date01/09/2011
Contact informationj.e.clarkson@dundee.ac.uk
Notes

Funding source: NIHR Health Technology Assessment Programme - HTA (UK)

Sample size: In total, 2288 participants will be recruited in order to retain 1735 at 4 years

Anticipated end date: 28/02/2017

Ancillary