The defining characteristic of a profession – and especially a health-care profession – is that the behaviour of its members is proscribed by a formal code of ethics. The main purpose of such codes is to guide practitioners' interactions with patients, assuring that patient interests are protected. In other words, the ethical code requires practitioners to place their patients' needs for proper diagnosis and appropriate treatment ahead of their own needs for income and advancement. The dental profession has a code of ethics that was developed by the American Dental Association many years ago; in most clinical situations, determination of proper behaviour is self-evident. However, the field of temporoman-dibular disorders (TMDs) has been the subject of considerable controversy for over half a century, and many people have argued that this makes it impossible to evaluate various approaches to treatment of TMDs within an ethical framework. In this article, the authors argue that the large volume of scientific evidence in the contemporary TMD literature provides an ethical framework for the diagnosis and treatment of patients with TMDs within a biopsychosocial medical model. They present a summary of the research with contemporary scientific integrity, which has produced that information over a period of many years. Based on that research, they conclude that dentists may provide conservative and reversible treatments that will be successful for most TMDs and in doing so will comply with the profession's code of ethics. Conversely, the authors claim that those dentists who continue to follow the older mechanistic models of TMD aetiology and treatment are not only out of step scientifically, but are placing their patients' welfare at risk by providing unnecessary irreversible bite-changing and jaw-repositioning interventions. Therefore, debate of these issues should not be solely focused on scientific merit, but also upon the compelling ethical obligations that dentists have as a result of the contemporary scientific literature regarding TMDs.

The aim of this study was to clarify the usefulness of colour-changing gum in evaluating masticatory performance after mandibulectomy. Thirty-nine patients who underwent mandibulectomy between 1982 and 2010 at Kobe University Hospital were recruited in this study. There were 21 male and 18 female subjects with a mean age of 64·7 years (range: 12–89 years) at the time of surgery. The participants included six patients who underwent marginal mandibulectomy, 21 patients who underwent segmental mandibulectomy and 12 patients who underwent hemimandibulectomy. The masticatory function was evaluated using colour-changing chewing gum, gummy jelly and a modified Sato's questionnaire. In all cases, the data were obtained more than 3 months after completing the patient's final prosthesis. The colour-changing gum scores correlated with both the gummy jelly scores (r = 0·634, P < 0·001) and the total scores of the modified Sato's questionnaire (r = 0·537, P < 0·001). In conclusion, colour-changing gum is a useful item for evaluating masticatory performance after mandibulectomy.

This study examined the aspect of the regulation of velum movement in the transition from the oral to pharyngeal phases of swallowing in relation to changes in the swallowing volume and viscosity by means of measurment of levator veli palatini muscle activity. The subjects were nine normal adults, ranging in age from 24 to 30 years. The swallowing volume was set at 1/4, 1/2 and 1 volume of the optimum volume of green tea for swallowing determined in each subject, and the viscosity was adjusted to 0, 2·0 and 4·6 Pa·s by mixing with thickener. Nine test foods were prepared in total. The electromyographic activity of the levator veli palatini muscle was monitored using bipolar hooked wire electrodes. The levator veli palatini muscle activity was defined as the integrated electromyographic wave. The mean in swallowing each test food was determined in each subject. The levator veli palatini muscle activity increased with the swallowing volume for all subjects (P < 0·05) and decreased inversely with the viscosity for six subjects (P < 0·05), but no change with the increase in the viscosity was noted for three subjects. This study clarified the aspect of the regulation of velar movement with regard to the involvement of the levator veli palatini muscle in swallowing activity with changes in the swallowing volume and viscosity.

Bite force has been measured by different methods and over a wide variety of designs. In several instruments, the fact that bite surface has been manufactured with stiff materials might interfere in obtaining reliable data, by a more prompt activation of inhibitory reflex mechanisms. The purpose of this study was to compare the maximum voluntary bite force measured by a digital occlusal force gauge (GM10 Nagano Keiki, Japan) between different opponent teeth, employing semi-hard or soft bite surfaces. A sample of 34 young adults with complete natural dentition was studied. The original semi-hard bite surface was exchanged by a soft one, made of leather and rubber. Maximum voluntary bite force recordings were made for each tooth group and for both bite surfaces. Statistical analyses (Student's t-test) revealed significant differences, with higher scores while using the soft surface across sexes and tooth groups (P < 0·05). Differential activation of periodontal mechanoreceptors of a specific tooth group is mainly conditioned by the hardness of the bite surface; a soft surface induces greater activation of elevator musculature, while a hard one induces inhibition more promptly. Thus, soft bite surfaces are recommended for higher reliability in maximum voluntary bite force recordings.

There is limited understanding of the subjective impact of congenital absence of teeth in patients with hypodontia. This study aimed to investigate the impact of mild, moderate and severe hypodontia on oral health-related quality of life (OHRQoL) and its relationship to age, gender and extent of hypodontia prior to treatment. 82 patients (43 females and 39 males, age range from 16 to 34 years) with a confirmed diagnosis of non-syndromic hypodontia were recruited for this study prior to treatment. Demographic details were recorded and a clinical examination documented the number and location of missing teeth. Participants were also asked to complete an oral health-related quality of life measure, the OHIP-49. The impact was of hypodontia was significant, with appearance concerns being the most prevalent impacts on oral health-related quality of life. Gender was a significant predictor of the overall OHIP-49 score, with females having higher level of impacts. The number and location of missing permanent teeth was not a good predictor of quality of life. However, location of missing teeth was a predictor of the psychological discomfort subscale score. There was a positive correlation between age and the functional limitation and physical disability subscale scores. This study shows that the impact of hypodontia on oral health-related quality of life is substantial.

The oral appliance (OA) is considered to be an effective treatment modality for obstructive sleep apnoea (OSA). Upper airway enlargement during OA therapy is critical, and lateral cephalometry has been used for the two-dimensional evaluation of upper airway form during this therapy. However, this method cannot provide an accurate three-dimensional (3D) view of upper airway form. To confirm the effects of OA on the upper airway in patients with OSAS, we performed CT in the presence and absence of OA in 15 Japanese patients (12 males, 3 females) who responded to OA therapy. CT in the presence and absence of OA was consecutively performed for each patient, and upper airway cross-sectional area in six arbitrary planes parallel to the palatal plane was measured. Next, 3D image reconstruction was performed; morphological changes in upper airway form were evaluated, and upper airway volume at three levels from the palatal plane to the deepest point of the epiglottis was measured. The cross-sectional area of two planes in the posterior soft palate region significantly increased in the presence of OA compared with that in the absence of OA. In the presence of OA, upper airway cross-sectional area and volume significantly increased in the posterior soft palate region compared with those in the posterior tongue region. 3D CT image reconstruction accurately confirmed morphological changes in the upper airway during OA therapy. Continued use of this 3D evaluation is expected to improve the results of OA therapy in the future.

This retrospective study evaluated the 5-year cumulative survival rate and complication rates of a 4·0-mm internal connection implant (MicroThread™ Osseospeed™, Astra Tech) installed for single-tooth restoration. The patients who were treated at Asan Medical Center between 2006 and 2007 were included in this study. A life table analysis was used to calculate the 5-year cumulative survival rate. Comparisons of cumulative survival rates among implant position (anterior, premolar and molar), jawbone (maxilla, mandible), gender and prosthesis type (screw-retained, cement-retained) were performed using the log-rank test. Post-loading complications were analysed using Fisher's exact test. Twelve of 136 implants (anterior; 22, premolar; 25, molar; 89) were lost during the loading period, and 11 were removed due to coronal fracture of fixture. The 5-year cumulative survival rate of the whole arch was 91·9%, and that of the molar region was 87·6%. Statistically significant differences were observed in cumulative survival rates among implant position (P = 0·037), whereas no statistically significant differences were observed among gender, jawbone, prosthesis type. Forty-seven of 114 (41·2%) implants in the posterior region showed post-loading complications, including coronal fracture of fixture and abutment screw loosening.

In recent years, there has been increasing interest in the relationship between dental occlusion and body posture both among people and in scientific literature. The aim of the present longitudinal study is to investigate the effects of an experimental occlusal interference on body posture by means of a force platform and an optoelectronic stereophotogrammetric analysis. An occlusal interference of a 0- to 2-mm-thick glass composite was prepared to disturb the intercuspal position while not creating interference during lateral or protrusive mandibular excursions. Frontal and sagittal kinematic parameters, dynamic gait measurements and superficial electromyographic (SEMG) activity of head and neck muscles were performed on 12 healthy subjects. Measurements were taken 10 days before the application of the occlusal interference, and then immediately before the application, the day after it, and at a distance of 7 and 14 days under four different exteroceptive conditions. The outcomes of this study show that an occlusal interference does not modify significantly over time static and dynamic parameters of body posture under different exteroceptive conditions. It has a minimal influence only on the frontal kinematic parameters related to mandibular position, and it induces a transient increase of the activity of masticatory muscles. In this study, the experimental occlusal interference did not significantly influence the body posture during a 14-day follow-up period.

Masticatory function is significantly lower in individuals with malocclusion than in those with normal occlusion. Although several studies suggest that masticatory function influences gastrointestinal digestive function, the relationship between malocclusion and gastrointestinal symptoms has not been studied extensively. We hypothesised that insufficient masticatory function would increase the functional burden of the stomach and have some influence on the gastrointestinal system. The purpose of this study was to investigate masticatory function and gastric emptying rate in subjects with malocclusion. Eleven healthy dentate female volunteers and eleven female patients with maloc-clusion underwent a ¹³C-acetate breath test with a liquid meal. Maximum ¹³CO₂ exhalation time (T_max) was compared statistically between both groups. Masticatory function was assessed by colour-changeable chewing gum. In addition, the frequency scale for the symptoms of gastroeso-phageal reflux disease (FSSG) and questionnaires on food intake were given to both groups. The mean T_max of the malocclusion group was significantly longer than that of the normal occlusion group (P = 0·007). Masticatory performance, measured by colour-changeable gum and questionnaires, was significantly lower in the malocclusion group than in the normal occlusion group (P = 0·023, P = 0·003). There was no significant difference in the FSSG results between the two groups (P = 0·262). This study suggested that there was a correlation between malocclusion and gastric emptying function in women.

The effect of unilateral anterior crossbite on the remodelling of mandibular condyle needs to be investigated. This study aimed to investigate the effects of experimentally created unilateral anterior crossbite on the remodelling of mandibular condyle and explore the changes in the expression of relevant transcription factors and growth factors. The experimental unilateral anterior crossbite was created in 6-week-old female growing rats by bonding metal tubes to the left pairs of incisors. Remodelings of mandibular condylar cartilage was assessed histologically at 2, 4 and 8 weeks. Protein and mRNA levels of Sox9, runt-related transcription factor 2 (Runx2), Osterix (Osx), transforming growth factor beta 1 (TGFβ1), transforming growth factor beta receptor 2 (TGFβr2) and type X collagen (ColX) were investigated by immunohistochemistry and real-time PCR, while alkaline phosphatise (ALP) by histochemistry and real-time PCR. Decreased ratio of hypertrophic cartilage layer was noticed in the 4w experimental group versus controls. At all the time points, the expression of Sox9 and ALP increased but that of TGFβ1 and TGFβr2 decreased in experimental groups (P < 0·05). The expression of Runx2, Osx and Col X increased at 2w, but decrease at 4w (P < 0·05). The results that obvious cartilage degradation and altered expression of related transcription factors and growth factors were detected in the mandibular condyles of the experimental group suggested that the present unilateral anterior crossbite plays an adverse role in the TMJ, and thus leading to the degenerative endochondral ossification.

The hyoid bone moves during swallowing due to contraction of suprahyoid muscles, which are critical components of normal swallowing function. It has been reported that the muscle force and shortening velocity decline gradually with age. Reduced hyoid velocities may delay the sealing of the laryngeal vestibule and opening of the cricopharyngeal muscle. We hypothesised that the hyoid velocity could be a factor influencing aspiration. This study evaluated effects of bolus volume changes on the hyoid distance and velocity in normal swallowing. The subjects were 21 healthy young adults. Lateral projection videofluorography was recorded while each subject swallowed 2·5, 5·0, 10 and 20 mL of liquid barium. We evaluated the maximum hyoid distance (Max d), anterior and superior distance (Max ad, Max sd). And, we evaluated the maximum velocity (Max v), anterior and superior velocity (Max av, Max sv). Two-way anova test revealed that Max d, Max ad and Max sd for different bolus volumes are not significantly different. But, two-way anova test showed statistically significant difference in Max v, Max av and Max sv among different bolus volume (P < 0·01). Tukey's test showed that there are significant differences in Max v between 2·5 and 20 mL, 5·0 and 20 mL, 10 and 20 mL, and 2·5 and 10 mL swallowing. And, Tukey's test showed significant differences in Max av and Max sv between 2·5 and 20 mL, 5·0 and 20 mL, and 10 and 20 mL swallowing. It is possible that a larger bolus volume requires greater maximum hyoid velocity. We plan to study hyoid velocity in elderly subjects and in those with dysphagia.

Complete denture fabrication involves a series of complex technical procedures. Nevertheless, simplified methods may be as effective as conventional ones albeit the lesser use of time and resources, without disadvantage for the patient. This study compared a simplified method for complete denture fabrication to a conventional protocol in terms of oral health-related quality of life (OHRQoL), patient satisfaction and denture quality. Forty-two edentulous patients requesting treatment with complete dentures were randomly allocated into two study groups. Group S received dentures fabricated by a simplified method and Group C received conventionally fabricated dentures. Before interventions and after three and 6 months following insertion, OHRQoL and patient satisfaction were analysed by specific instruments. A prosthodontist assessed denture quality 3 months after delivery. Groups presented no difference for OHRQoL, denture quality and general satisfaction. Differences regarding patient satisfaction with some aspects of the dentures were found after 3 months (S > C), but were insignificant at 6 months. It was concluded that the simplified method is able to produce dentures of a quality comparable to those produced by the conventional method, influencing OHRQoL and patient satisfaction similarly.

A number of variables may influence the outcome of complete denture therapy. The objective of this study was to verify possible correlations between previous experience with dentures, patient expectation and the number of post-delivery adjustments with patient satisfaction after treatment. One hundred patients (mean age 61·9 ± 10·3) rated their previous experiences with complete dentures and their expectations before and satisfaction after treatment on a visual analogue scale (VAS) using scores from 0 (worst results) to 10 (best results). The number of post-delivery adjustments and other patient-related clinical variables was also noted. Patient expectation scores were higher than previous experience scores and satisfaction after treatment scores. Positive and weak correlations were found between previous chewing experiences with complete dentures, with regard to chewing expectations and comfort of use. Phonetics and comfort of use in previous experiences presented a positive correlation with expectations for chewing, aesthetics, phonetics and comfort of use. Groups of patients with different levels of education presented significant differences in expectation scores regarding comfort of use as well. A negative and weak correlation was found between phonetics satisfaction and the number of post-delivery adjustments. Patients' expectations for the therapy were higher than their satisfaction after treatment. Previous experiences with complete dentures could slightly influence patients' expectations and satisfaction, whereas lower scores for previous experience with complete dentures caused lower scores for both expectation and satisfaction. Patients' educational levels and the number of post-delivery adjustments influenced negatively the expectations about comfort of use and patient satisfaction, respectively.

The purpose of this in vitro study was to assess the breaking load of zirconia-based crowns veneered with either CAD/CAM-produced or manually layered feldspathic ceramic. Thirty-two identical zirconia frameworks (Sirona inCoris ZI, mono L F1), 0·6 mm thick with an anatomically shaped occlusal area, were constructed (Sirona inLab 3.80). Sixteen of the crowns were then veneered by the use of CAD/CAM-fabricated feldspathic ceramic (CEREC Bloc, Sirona) and 16 by the use of hand-layered ceramic. The CAD/CAM-manufactured veneer was attached to the frameworks by the use of Panavia 2.0 (Kuraray). Half of the specimens were loaded until failure without artificial ageing; the other half of the specimens underwent thermal cycling and cyclic loading (1·2 million chewing cycles, force magnitude F_max = 108 N) before the assessment of the ultimate load. To investigate the new technique further, finite element (FE) computations were conducted on the basis of the original geometry. Statistical assessment was made by the use of non-parametric tests. Initial breaking load was significantly higher in the hand-layered group than in the CAD/CAM group (mean: 1165·86 N versus 395·45 N). During chewing simulation, however, 87·5% (7/8) of the crowns in the hand-layered group failed, whereas no crown in the CAD/CAM group failed. The CAD/CAM-produced veneer was significantly less sensitive to ageing than the hand-layered veneer.

The aims of this systematic review were to investigate the success rates of prosthetic restorations on endodontically treated teeth and their manner of failure. PubMed and hand literature searches were conducted on studies published until June 2012. Only clinical studies on human subjects referring to the success rates of prosthetic restorations on endodontically treated teeth with a follow-up period of at least 6 years were reviewed. A total of four studies were identified. Meta-analysis showed the success rate to be 92% (CI 82–98%) for single crowns on endodontically treated teeth and 79% (72–86%) for fixed dental prostheses. Only one study reported on removable dental prostheses with a success rate of 66%. Single crowns on teeth restored without posts demonstrated a success rate of 94% (CI 84–99%), whereas where posts were placed, the success rate was lower (92% CI 82–98%). Single crowns over cast post-and-cores and prefabricated posts showed success rates of 93% (CI 82–99%) and 94% (CI 90–97%), respectively; both differences were not statistically significant (significance level of 5%). The most common reason for failure was post-debonding. Single crowns seem to be the best treatment modality for endodontically treated teeth. However, due to the low number of studies included and their design, the results of this systematic review should be interpreted with caution. Further clinical studies are needed to provide high-quality evidence on the topic.

The purpose of this study was to evaluate patient-centred outcomes with regard to function and comfort after placement of mini-implants for stabilisation of complete dentures. The trial was designed as a prospective cohort of 12-months duration and involved 21 subjects in the age of 50–90 years having a full denture in the maxilla or the mandible with poor stability during function. Flapless installation of 2–4 narrow-body Dentatus Atlas^® implants was performed and retention for the existing denture was obtained by the use of a silicone-based soft lining material (Tuf-Link^®). Patients' judgement of perceived satisfaction with function and comfort of the dentures was recorded at baseline, 1- and 12-months post-treatment using 10-centimetre visual analogue scales (VAS) and a questionnaire. Clinical examination of the conditions of the peri-implant soft tissues was performed at 12 months. Nineteen of the 21 patients were available for the 12-month follow-up examination. The two drop-out subjects lost all implants within 1 month and rejected retreatment. Further six subjects lost 1–2 implants, but were sucessfully retreated by insertion of new implants. Overall satisfaction, chewing and speaking comfort were all markedly improved from pre-treatment median VAS scores of around 4–5 to median scores of 9·0–10 (10 = optimal) at the final examination. The prevalence of positive answers to questions regarding stability/function of the denture increased significantly to almost 100% for all questions. Treatment involving maxillary dentures and the use of short implants (7–10 mm) was associated with an increased risk of implant failure. The results indicate that placement of mini-implants as retentive elements for full dentures with poor functional stability has a marked positive impact on the patients' perception of oral function and comfort as well as security in social life.

The aim of this study was to investigate whether intramuscular administration of the 5-HT₃ receptor antagonist granisetron reduces experimental muscle pain induced by repeated intramuscular injections of acidic saline into the masseter muscles. Twenty-eight healthy and pain-free volunteers, fourteen women and fourteen men participated in this randomized, double-blind and placebo-controlled study. After a screening examination and registration of the baseline pressure–pain threshold (PPT), the first simultaneous bilateral injections of 0·5 mL acidic saline (9 mg mL⁻¹, pH 3·3) into the masseter muscles were performed. Two days later, PPT and pain (VAS) were re-assessed. The masseter muscle was then pre-treated with 0·5 mL granisetron (Kytril^® 1 mg mL⁻¹ pH 5·3) on one side and control substance (isotonic saline, 9 mg mL⁻¹ pH 6) on the contralateral side. Two minutes thereafter a bilateral simultaneous injection of 0·5 mL acidic saline followed. The evoked pain intensity, pain duration, pain area and PPT were assessed. The volunteers returned 1 week later to re-assess VAS and PPT. On the side pre-treated with granisetron, the induced pain had significantly lower intensity and shorter duration (P < 0·05) compared with the side pre-treated with control. A subgroup analysis showed that the effect of granisetron on pain duration was significant only in women (P < 0·001), while the effect on peak pain and pain area were significant in both sexes. The results showed no significant change in PPT. In conclusion, these results indicate that granisetron has a pain-reducing effect on experimentally induced muscle pain by repeated acidic saline injection.

This is a randomised placebo-controlled clinical trial investigating the efficacy of hydroxyzine for treating parent-reported sleep bruxism in children. Participants of this trial were 30 patients randomly allocated to one of the two groups in a ratio of 1:2. One group received hydroxyzine and the other group received placebo. The outcome measures were Visual Analogue Scale test and Clinical Global Severity scale. Assessments occurred at baseline and at the end of week 4. The side effects of drugs were assessed using a checklist. The number of children in the hydroxyzine and placebo groups was 21 and 9, respectively. The mean age of children in the hydroxyzine and placebo groups was 8·4(s.d. = 3·3) and 6·5(s.d. = 1·5) years, respectively. Hydroxyzine more than placebo decreased bruxism score (3·8 versus 2·2). No serious adverse effect was reported. Current evidence support that hydroxyzine is effective and well tolerated for treating bruxism in children.

Although adults with mandibular prognathism are known to show impaired smoothness of masticatory jaw movements, it remains uncertain whether/how the surgical-orthodontic treatment is effective to improve masticatory jaw movements. The aims of this study were (i) to verify whether the surgical-orthodontic treatment of patients with mandibular prognathism improve smoothness of the chewing jaw movements post-operatively and, if so, (ii) to examine whether the improved parameters show similar quantities as those of the control subjects. The chewing jaw movements for 13 patients with mandibular prognathism were recorded at pre- and post-treatment stages. The patient group was divided into two groups: Class III_closed showed full occlusal contact at the habitual intercuspal position, whereas Class III_open showed inability of occlusal contact between the upper and lower anterior teeth. The control group (CG) consisted of 52 subjects having acceptably good occlusion. The normalised jerk cost (NJC), movement duration and peak velocity in jaw closing were compared. For both Class III_open and Class III_closed groups, statistical comparisons revealed that the NJC and movement duration were decreased after the treatment, whereas the peak velocity was increased (all P < 0·01). For the Class III_open, these quantities at the post-treatment stage did not show any significant differences compared with those for the CG. It is concluded that the smoothness of chewing jaw movements for patient with mandibular prognathism were improved after treatment, and for the patients with anterior open bite at pre-treatment, the post-operatively achieved smoothness of jaw-closing movements did not differ from those of the CG.

The aim of this study was to examine the effect of mouth breathing on masticatory muscle activity during chewing food. Masseter muscle activity during chewing of a rice ball was recorded in 45 adult volunteers (three women), identified as nose breathers. Surface electrodes were placed on the skin according to the orientation of the masseter muscle to record the activity of this muscle while the subjects chewed the food until swallowing. Each activity was recorded twice, once with nose breathing and once with mouth breathing induced by nasal obstruction. The integrated and mean electromyography values for mouth breathing were significantly lower than the values for nose breathing (P < 0·05). The resting and total duration of chewing were significantly prolonged (P < 0·05) and the active duration significantly shorter (P < 0·05) when breathing through the mouth compared with the nose. Significantly more chewing strokes were counted for mouth breathing compared with nose breathing (P < 0·05). Taken together, the results indicate that mouth breathing decreases chewing activity and reduces the vertical effect upon the posterior teeth.

To describe the natural course of temporomandibular disorders (TMD) in patients with low levels of pain-related impairment, independently by the physical diagnoses they received. Amongst all patients who attended the TMD Clinic, University of Padova, Italy, during the year 2009, those who: (i) had Research Diagnostic Criteria for TMD (RDC/TMD) axis II Graded Chronic Pain Scale (GCPS) grade 0 or 1 scores, (ii) received counselling on their signs and symptoms at the time of their first visit and suggestions on how to self-manage their symptoms, (iii) did not attend the Clinic since the time of their last visit and (iv) were visited by the same resident, were recalled for a follow-up assessment during the period from September to December 2011. Sixty-nine patients (79% females; mean age 47.4 ± 11.3 years; range 26–77) of 86 who were potentially eligible accepted to enter the study. The time span since the first visit ranged from 23 to 36 months. At the follow-up assessment, the percentage of patients with muscle disorders decreased from 68.1% to 23.1%; disc displacement with reduction remained unchanged (52.1%), whilst the 5.7% of patients who had disc displacement without reduction with limited opening then showed absence of limitation; diagnoses related to other joint disorders decreased from 30.4% to 14.4% for arthralgia and from 27.5% to 24.6% for osteoarthritis/osteoarthrosis. In a sample of patients TMD with low pain-related impairment followed up with a single recall assessment at 2-to-3 years, the natural course of disease was generally favourable.

Twelve young adults in a good general health were observed during habitual posture of tongue and jaw in different emotional conditions induced by watching three video sequences. The position of the mandible was tracked by the displacements of an electromagnetic sensor glued to the chin. The tongue-to-palate distance was obtained by 2-D location of three electromagnetic sensors placed on the tongue upper midline surface. Head displacements were evaluated with a sensor fixed to an upper central incisor and were subtracted from corresponding displacements of tongue and chin sensors to obtain the real tongue and mandible positions during continuous recording sequences. Emotional conditioning by a fear movie influenced the vertical position of the mandible: the mean interarch distances during the fear movie (2·34 ± 0·24 mm) were significantly different from those measured during the tender (3·13 ± 0·35) and neutral (3·42 ± 0·80) movies, respectively (anova repeated measure, SNK; P < 0·05). anova repeated measure indicated that the tongue-to-palate distance differed significantly when the subjects were watching the conditioning movies (P = 0·003), the tip of the tongue taking a lower position during the fear movie than during the tender and neutral movies.

Velopharyngeal closure plays an important role in preventing air pressure leakage during swallowing and phonation from oropharynx to nasopharynx. Levator veli palatini muscle activity is influenced by oral and nasal air pressure, volume of the swallow bolus and postural changes. However, it is unclear how velopharyngeal closing pressure is affected by reclining posture. The purpose of this study was to investigate the effects of reclining posture on velopharyngeal closing pressure during swallowing and phonation. Nine healthy male volunteers (age range, 27−34 years) participated in this study. Velopharyngeal closing pressure during a dry swallow, a 5-mL liquid swallow, a 5-mL honey-thick liquid swallow and phonations of /P∧/ and /K∧/ were evaluated in an upright posture and at reclining postures of 60° and 30°. A manometer catheter was inserted transnasally onto the soft palate, and each trial was repeated three times. A solid-state manometer catheter with an intra-luminal transducer was used to evaluate the amplitude and duration of each trial, and data were statistically analysed. Average amplitudes during dry and liquid swallows were significantly lower in reclining postures compared with the upright posture, but the amplitude was not significantly different during the thick liquid swallow. Average durations were not affected by postural changes. The amplitudes during phonations were lower in reclining postures, but the differences were not significant. Velopharyngeal closure is significantly affected by reclining posture. This suggests that velopharyngeal closing pressure may be adjusted according to afferent inputs, such as reclining posture and bolus viscosity.

Marginal bone level is a criterion for implant success. The aetiological factors of bone loss have not been clarified. The aim of this study was to evaluate the influence of implant systems and prosthetic materials on the marginal bone loss. Twenty-three patients participated; two implant systems and three superstructure materials were used in this study. Twenty-two of the implants were restored with porcelain fused to base metal alloy (BMA), 25 with porcelain fused to noble metal alloy (NMA) and 20 with zirconium oxide-based ceramics. Radiographs were taken at baseline and 3, 6 and 12 months after loading. Crestal bone-level changes were assessed with digital subtraction radiographs. The effects of superstructure materials and implants were evaluated with one-way anova and independent samples t-test, respectively (α = 0·05). The mean crestal bone loss was found 0·483 mm in 3 months, 0·622 mm in 6 months and 0·816 mm in 12 months. Prosthetic materials were found to have greater effect (β = 0·575, P = 0·015) on crestal bone loss than implant systems (P > 0·05). The porcelain fused to BMA restorations showed higher crestal bone loss than NMA-based restorations (P = 0·003) at 3 months, (P = 0·038), at 6 months and (P = 0·00) at 12 months; however, crestal bone loss differences between NMA and zirconia were not significant (P = 0·629) at 3 months, (P = 0·974) at 6 months and (P = 1) at 12 months. Within the limitations of this study, our results revealed that rather than the implant systems, prosthetic materials seemed to have an effective role on crestal bone.

Teeth can be extracted due to multiple factors. The aim of this retrospective cross-sectional study was to identify the relative contribution of restorative treatments to tooth loss. The study reviewed records of 826 patients (1102 teeth). Patient's gender, age and education were obtained. In addition to the main reason for extraction (caries, periodontal disease, pre-prosthetic extraction, restorative failure and remaining root), the following information was collected about each extracted tooth: type, the status of caries if any (primary or secondary) and pulpal status (normal or reversible pulpitis, irreversible pulpitis, necrotic or root canal treated) and type and size of restoration, if present. Following data collection, descriptive analysis was performed. A log-linear model was used to examine the association between restorative treatment and tooth loss and between reasons for tooth loss and type of tooth. Lower molars followed by upper molars were the most commonly extracted teeth. Teeth with no restorations or with crowns were less likely to be extracted (P < 0·001). Lower and upper molars and lower premolars were more likely to be extracted due to restorative failure, while lower anterior teeth were more likely to be extracted due to periodontal disease (P < 0·05). Twenty two per cent of the extractions was due to restorative failure, and at least 65·9% of these teeth had secondary caries. Gender, age and educational level were factors that affect tooth loss. In conclusion, teeth receiving multiple restorative therapies were more likely to be extracted.

There is still debate over whether the effect of transcutaneous neuromuscular electrical stimulation (NMES) in dysphagia rehabilitation is superior to traditional therapy (TT). The purpose of this meta-analysis was to assess the overall efficacy by comparing the two treatment protocols. Published medical studies in the English language were obtained by comprehensive searches of the Medline, Cochrane and EMBASE databases from January 1966 to December 2011. Studies that compared the efficacy of treatment and clinical outcomes of NMES versus TT in dysphagia rehabilitation were assessed. Two reviewers independently performed data extraction. Data assessing swallowing function improvement were extracted as scores on the Swallowing Function Scale as the change from baseline (change scores). Seven studies were eligible for inclusion, including 291 patients, 175 of whom received NMES and 116 of whom received TT. Of the seven studies, there were two randomised controlled trials, one multicentre randomised controlled trial and four clinical controlled trials. The change scores on the Swallowing Function Scale of patients with dysphagia treated with NMES were significantly higher compared with patients treated with TT [standardised mean difference (SMD) = 0·77, 95% confidence interval (CI): 0·13 to 1·41, P = 0·02]. However, subgroup analysis according to aetiology showed that there were no differences between NMES and TT in dysphagia post-stroke (SMD = 0·78, 95% CI: −0·22 to 1·78, P = 0·13, 4 studies, 175 patients). No studies reported complications of NMES. NMES is more effective for treatment of adult dysphagia patients of variable aetiologies than TT. However, in patients with dysphagia post-stroke, the effectiveness was comparable.