Quality of life and psychological well-being among endodontic patients: a case-control study
Professor Colman McGrath
Clinical Professor in Dental Public Health
Faculty of Dentistry
The University of Hong Kong
Prince Philip Dental Hospital
34 Hospital Road
Sai Ying Pun
Hong Kong SAR
Background: Much is already known about the consequences of endodontic disease from clinicians’ perspectives; a significant omission is an understanding from patients’ perspectives. This study aimed to determine oral health-related quality of life (OHQoL) and psychological distress among subjects referred for endodontic care compared to patients in periodontal maintenance.
Methods: This was a case-control study involving 200 patients; 100 patients requiring endodontic treatment and 100 control subjects (periodontal maintenance patients). OHQoL was assessed using the short form Oral Health Impact Profile measure (OHIP-14) and psychological well-being using the short form of the General Health Questionnaire (GHQ-12). Variations in OHIP-14 and GHQ-12 scores between the ‘case’ and ‘control’ group were determined, and the magnitude of such differences through effect size (ES) calculations.
Results: There were significant differences in OHIP-14 summary scores between the case and control groups (p < 0.001) and significant differences across all seven domain scores (p < 0.05). The ES was moderate (0.63) with respect to summary OHIP-14 scores. There were also significant differences in GHQ-12 scores between the case and control groups (p < 0.05), but the ES was small (0.36).
Conclusions: OHQoL and psychological well-being is compromised among patients seeking endodontic treatment, and to a greater magnitude than patients in periodontal maintenance.
Abbreviations and acronyms:
decayed, missing and filled teeth
Community Periodontal Index
General Health Questionnaire
Oral Health Impact Profile
oral health-related quality of life
quality of life
Much is already known about the consequences of endodontic disease from clinicians’ perspectives in terms of clinical features, microbiological factors and radiographic characteristics.1,2 A significant omission in endodontic research is the lack of information from patients’ perspectives of the consequences of endodontic disease.3 It is acknowledged that a clinician’s perspective of oral health in itself provides a very limited understanding of oral health.4 This in turn has led to an explosion of interest in patients’ perspectives of their oral health and, specifically, how oral health affects their physical, psychological and social functioning – their oral health-related quality of life (OHQoL).5
Within endodontics, consideration of patients’ perspectives has been very limited aside from symptoms such as pain reports.6,7 Arguably, it is not simply the existence of signs and symptoms that are important to ascertain but rather to assess how these signs and symptoms impact a patient physically, socially and psychologically – their quality of life (QoL) – so as to determine treatment need and ultimately treatment success.8
Another key issue to determine is how a particular (oral) condition impacts on psychological well-being, i.e. causes distress to patients. To date information has been obtained with respect to influence of tooth loss,9 oral mucosal conditions10 and orofacial pain11 on psychological well-being but information with respect to endodontic status is lacking.
This study aimed to determine OHQoL and psychological distress among subjects referred for endodontic care and to compare such attributes with patients in periodontal maintenance.
This case-control patient-centred study was approved by the Institutional Review Board of the University of Hong Kong and the Hospital Authority, Hong Kong (HKU/HA HKW IRB UW 07-1177) and conducted in the Prince Philip Dental Hospital, Hong Kong SAR, China.
The case group was identified from a waiting list of patients referred to the Discipline of Endodontics for consultation and confirmed to require endodontic treatment. All patients with clinical evidence of endodontic problems were identified during screening and deemed to require root canal therapy. Patients with acute pain are seen in the accident and emergency department and would have had first stage endodontic treatment carried out and thereby did not form part of the study group. The following inclusion and exclusion criteria were employed: inclusion criteria – (1) adults aged 18 and older; (2) of Chinese ethnicity; (3) be able to speak Cantonese and read traditional Chinese; (4) patients screening records indicated no more than five missing teeth and no more than two decayed teeth. Exclusion criteria – (1) patients with serious medical conditions for which they were hospitalized in the past year; and/or taking medication for their medical condition that required consultation with a physician prior to dental treatment; (2) patients with physical disabilities; (3) any communication difficulties noted on the patient’s record. Patients were recruited over a one-year period.
The control group was recruited from a list of patients scheduled for routine periodontal maintenance at the dental hygiene clinic in the Discipline of Periodontology of the same hospital. A gender and age (±5 years) matched sample of patients was identified from the hospital’s electronic dental record (SALUD). The dental records of the potential control group sample were screened using similar inclusion and exclusion criteria to those for the case group with the exception obviously of not requiring an endodontic consultation. The control group recruitment lasted over a three-month period.
Previous case-control studies on OHQoL with respect to specific oral conditions such as tooth wear,12 dentofacial deformities,13 and malocclusion14 have used a sample size of between 70 and 100 subjects per group to identify differences in OHQoL between the case and control groups. As no case-control study has been performed with respect to endodontic status and OHQoL, it seemed prudent in this study to use a sample of 200 subjects (100 case and 100 control).
The data collection for this study consisted of a constructed questionnaire consisting of three components: (1) OHQoL assessment; (2) psychological well-being assessment; and (3) socio-demographic information.
In assessing OHQoL, the short form of the Oral Health Impact Profile (OHIP-14)15 was employed. OHIP-14 consists of 14 questions arranged over seven domains (physical functioning, physical pain, physiological disability, physical disability, psychological disability, social disability and handicap) based on the WHO’s theoretical model of disease-impairment-disability-handicap model adapted for oral health by Locker.16 Participants were asked to rate the frequency of an event occurring as described by the OHIP-14 on a 5-point Likert scale: ‘never’ (score 0), ‘hardly ever’ (score 1), ‘occasionally’ (score 2), ‘fairly often’ (score 3) and ‘very often’ (score 4) in the last month. An overall OHIP-14 summary score can be derived by summating responses to all items and scores can range from 0 to 56. Individual domain scores can be derived by summating responses to the two items within the particular domain and scores can range from 0 to 8. A higher OHIP-14 indicates poorer OHQoL life. A Chinese version of OHIP-14 has been developed and its psychometric properties evaluated.17
In assessing psychological well-being, the 12-item General Health Questionnaire (GHQ-12) was employed.18 It consists of a checklist of statements on psychological well-being asking respondents to compare their recent experience to their usual state on a 4-point Likert scale. Six of the items are positively phrased and six negatively phrased. Summary GHQ-12 scores can range from 0 to 12 with a higher score indicative of poorer psychological well-being; a threshold score of ≥4 is indicative of morbidity/distress.19 GHQ-12 is increasingly being used within dental research because it is a brief measure and less complicated to complete than many others. A Chinese version of the GHQ-12 has been developed and its psychometric properties validated.20
Information on socio-demographics was also collected, including age (in years), gender, formal educational attainment level (highest level attained: no formal/primary school, secondary school or college/university education) and personal monthly income level (HK$0–9999/month, HK$10 000–$19 999, HK$20 000–$29 999 or HK$30 000 or above (US$1 = HK$7.8).
All data were analysed using the statistical software package SPSS for Windows (SPSS 18.0, SPSS Inc, Chicago). A comparison of the case and control group with respect to socio-demographics (age, gender, educational attainment and family income level) and clinical oral health status (including dental caries experience [the overall number of decayed, missing and filled teeth, DMFT], periodontal health status [Community Periodontal Index, CPI] and prosthetic status) was conducted using chi-square test (for categorical data) and Mann–Whitney U test (a non-parametric equivalent to the Student’s t-test for continuous data). Variations in OHIP-14 scores and GHQ-12 scores between the case and control group was examined using the Mann–Whitney U test. The magnitude of the statistical difference in OHIP-14 and GHQ-12 scores between the case and control groups was determined through effect size (ES) calculations (ES = mean of case group – mean of control group divided by the SD of the pooled case and control group).21 ES can be interpreted using Cohen’s criteria to infer the magnitude of difference in OHIP-14 and GHQ-12 scores between the groups.
To attain a sample of 100 case subjects, 106 consecutive patients attending for consultation of a single tooth for primary endodontic treatment were invited to participate (response rate 94.3%). To attain a sample of 100 control subjects (matched for gender and age [±5 years] to the control sample), 112 subjects were approached at the oral hygiene maintenance clinic to participate (response rate 89.3%). There was no significant difference in the response (participatory) rate between the case and control groups (p > 0.05).
The socio-demographic profile and the clinical oral health status of the two study groups are presented in Table 1. The mean age of the case group was 45.1 (SD 15.7) compared with a mean age of 45.2 (SD 12.2) among the control group (p > 0.05). Level of formal educational attainment was similar in both the case and control group with the majority of subjects attaining secondary or tertiary education, 71.0% and 77.0% respectively (p > 0.05). There was no significant difference in monthly (personal) income level between the case and control group (25 of the case group and 30 of the control group reported to earn HK$10 000 or more per month) (p > 0.05).
Table 1. Socio-demographic backgrounds and oral health status of the case and control study participants
|Gender % (number)|| || ||---|
| Male||43.0 (43)||43.0 (43)|
| Female||57.0 (57)||57.0 (57)|
|Education level % (number)|| || ||0.625|
| Up to primary school ||29.0 (29)||23.0 (23)|
| Secondary school ||55.0 (55)||60.0 (60)|
| Post-secondary school||16.0 (16)||17.0 (17)|
|Income per month†% (number)|| || ||0.752|
| HK$ 0–9999||74.0 (71)||69.1 (67)|
| HK$ 10 000–19 999||21.9 (21)||25.8 (25)|
| HK$ 20 000 and above||4.2 (4)||5.2 (5)|
|Dentition status Mean (SD)|
| DMFT ||8.6 ± 3.2||7.6 ± 4.8||0.085|
| DT||1.1 ± 0.9||0.2 ± 0.4||<0.001|
| FT ||4.0 ± 3.8||3.7 ± 3.9||0.598|
| MT||3.5 ± 1.4||4.1 ± 3.1||0.293|
|Periodontal status % (number)|| || ||<0.001|
| CPI score <3||58.0 (58)||34.0 (34)|
| CPI score ≥3||42.0 (42)||66.0 (66)|| |
|Prosthetic status % (number)|| || ||0.631|
| No removable denture||92.0 (92)||89.0 (89)|
| With removable denture||8.0 (8)||11.0 (11)|| |
In terms of the overall number of decayed, missing and filled teeth, the mean DMFT was 8.6 (SD 3.2) among the case group and 7.6 (SD 4.8) among the control group (p > 0.05). The case group had a significantly higher number of untreated decayed teeth (DT) compared to the control group; 1.1 (SD 0.9) for the case group versus 0.2 (SD 0.4) for the control group (p < 0.001). There was no significant difference in the number of missing teeth (MT) nor in the number of filled teeth (FT) between the case and control group (p > 0.05). In terms of periodontal health status, there was a significant difference in the periodontal health status between the case and control group (p < 0.001). In the control group, 66.0% had periodontal pockets (CPI score ≥3) compared to 42% in the control group. Among the case group, 8% possessed a removable partial denture compared with 11% of the control group (p > 0.05).
There was a significant difference in OHQoL between the case and control group (Table 2). The mean OHIP-14 summary score among the case group was 13.9 (SD 9.9) versus 8.2 (SD 7.3) among the control group (p < 0.001). The magnitude of the statistical difference (ES) was 0.63. Across all of the seven OHIP-14 domains there were significant differences in mean scores between the case and control group: functional limitations (p < 0.001); physical pain (p < 0.001); psychological discomfort (p < 0.001); physical disability (p < 0.01); psychological discomfort (p < 0.01); social disability (p < 0.01) and handicap (p < 0.05). The ES across the domains ranged from 0.38 (handicap domain) to 0.74 (physical pain domain).
Table 2. Comparison of OHIP-14 and GHQ-12 scores (mean ± SD) between the case and control groups
|OHIP-14 summary score||13.9 ± 9.9||8.2 ± 7.3||<0.001||0.63|
| Domain additive scores |
|Functional limitation||1.3 ± 1.6||0.7 ± 1.0||<0.001||0.70|
|Physical pain||2.8 ± 1.6||1.6 ± 1.3||<0.001||0.74|
|Psychological discomfort||2.4 ± 1.9||1.4 ± 1.5||<0.001||0.52|
|Physical disability||2.3 ± 2.1||1.4 ± 1.5||0.001||0.52|
|Psychological disability||2.2 ± 1.8||1.4 ± 1.5||0.001||0.49|
|Social disability||1.5 ± 1.7||0.8 ± 1.1||0.003||0.49|
|Handicap||1.5 ± 1.7||0.9 ± 1.3||0.013||0.38|
|GHQ-12||1.6 ± 2.6||0.8 ± 1.7||0.014||0.36|
There was also a significant difference in psychological well-being between the case and control group. The mean GHQ-12 summary score among the case group was 1.6 (SD 2.6) compared with a mean GHQ-12 summary score of 0.8 (SD 1.7) among the control group (p < 0.05). The magnitude of the statistical difference (ES) was 0.36 (1.6 – 0.8/2.2). Among the case group, 17% had a GHQ-12 summary score of ≥4 compared with 4% of those in the control group having a GHQ-12 summary score of ≥4 (p < 0.01).
The case-control study design lends itself readily to identify differences in QoL between those with and without endodontic disease and thereby provide empirical evidence of compromised QoL and psychological well-being among patients with endodontic concern. The high response rate demonstrates the feasibility of using patient centered assessments in the clinical setting and patients’ willingness to share their experiences to provide a more comprehensive assessment of their oral health.22 Patients with endodontic disease are not a homogenous group and can present with different clinical signs and symptoms. In this sample, patients were recruited from the waiting list; patients with acute pain are seen in the accident and emergency department and would have had first stage endodontic treatment carried out and thereby did not form part of the study group. In addition, multiple inclusion and exclusion criteria were employed to limit potential bias of multiple endodontic problems and/or other health (and oral health) concerns on OHQoL. It is difficult to strictly identify a control group who were similar in all respects to the case group with the exception of no endodontic disease. Consideration was given to matching the groups by key variables (age and gender) and controlling for similar inclusion and exclusion criteria. The use of periodontal maintenance patients as a control group was a useful comparison group. The case and control group were similar in many respects in terms of socio-demographics and several of the clinical variables. Nonetheless, the case group had higher dental caries experience (more untreated decay) as one would expect given that caries is a key factor that gives rise to endodontic disease.23 The control group, the periodontal maintenance group, had a greater evidence of periodontal disease experience (a greater proportion with periodontal pockets) than the case group. However, it should be borne in mind that their periodontal disease was controlled and they were in regular maintenance. Nevertheless, it is accepted that previous periodontal disease (and the signs and symptoms associated with this) may have had some influence on QoL, at least to some extent.24 Furthermore, it is acknowledged that patients awaiting treatment, as opposed to those in maintenance, are likely to be more informed regarding their disease(s), consequences and treatment(s), which may have an influence on their subjective health status ratings. In any case this case-control study was able to differentiate between those with endodontic disease and those with controlled and maintained oral health problems.
There were significant differences in overall OHIP-14 summary scorers and all of its seven domains. The magnitude of the statistical difference was moderate (ES ≥0.50 and <0.70) in terms of overall score but was large (ES ≥0.70) in some domains, i.e. physical pain and functional limitation.21 Thus, it can be inferred that OHQoL is compromised considerably in patients requiring endodontic care and in many aspects; and more so than patients in periodontal health maintenance (with controlled periodontal disease).
There were significant differences in psychological well-being between the case and control group, and more of the case group has what could be categorized as ‘distressing morbidity’ than those in the control group.19 However, the magnitude of the statistical difference could best be described as small (ES ≥0.2 and <0.50).21 Thus, it can be inferred that compromised psychological well-being is evident among patients requiring endodontic care and in some cases this maybe severe (approximately one-in-six had scores indicative of ‘morbidity/distress’). Further studies are warranted to investigate what are the key endodontic factors associated with OHQoL and psychological well-being and whether in fact endodontic treatment improves OHQoL and psychological well-being.
In conclusion, this case-control study identified significant differences in OHQoL and psychological well-being among patients requiring endodontic treatment compared to patients in periodontal maintenance.