ABSTRACT: Tardive dyskinesia remains an elusive and significant clinical entity that can possibly be understood via experimentation with animal models. We conducted a literature review on tardive dyskinesia modeling. Subchronic antipsychotic drug exposure is a standard approach to model tardive dyskinesia in rodents. Vacuous chewing movements constitute the most common pattern of expression of purposeless oral movements and represent an impermanent response, with individual and strain susceptibility differences. Transgenic mice are also used to address the contribution of adaptive and maladaptive signals induced during antipsychotic drug exposure. An emphasis on non-human primate modeling is proposed, and past experimental observations reviewed in various monkey species. Rodent and primate models are complementary, but the non-human primate model appears more convincingly similar to the human condition and better suited to address therapeutic issues against tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a neurological motor complication eventually arising in one-third of patients chronically exposed to antipsychotic drugs. Some orodental peripheral factors have been reported to influence TD. OBJECTIVE: To measure orodental factors such as temporomandibular joint function, static occlusal contacts, and denture condition, and attempt correlations with orofacial TD intensity. METHODS: In this exploratory cross-sectional pilot study, 31 subjects between 30 and 75 years of age were divided in two groups displaying minimal to mild, or moderate to severe orofacial TD, respectively, and underwent a detailed oral, dental, and prosthetic evaluation to capture various aspects of oral health compared between the two groups. Blinded video-based TD ratings along a validated scale were obtained to compare dentulous and edentulous subjects, and contrast TD intensity in complete denture wearers with and without their own prostheses. RESULTS: None of the factors examined tightly correlated with orofacial TD intensity. However, edentulism was associated with a higher median orofacial TD rating compared to the dentulous group (p = 0.001). Further, a significant intra-subject difference was observed in the edentulous subjects rated with their own complete dentures in place or not (p = 0.028), the dentures attenuating the mean orofacial ratings by 21.8 ± 7.3%. CONCLUSION: Of all orodental factors considered, only edentulism and complete denture wearing influenced oral TD expression, calling for the close monitoring of the dental status in antipsychotic drug-exposed patients to prevent tooth loss. Further studies to measure the impact of an adequate prosthodontic rehabilitation in edentulous subjects with orofacial TD seem warranted.

BACKGROUND: Drug-induced parkinsonism (DIP) is seen in one third of patients exposed to antipsychotic drugs and may lead to complications related to dysphagia and falls. Aside from skilled neurological examination, no tool has been validated to facilitate detection and follow-up. OBJECTIVE: In this pilot study, three validated screening instruments were tested in an age-biased cohort of schizophrenia patients, including four items of the Liverpool University Neuroleptic Side-Effects Rating Scale (LUNSERS) and two brief questionnaires designed for community survey of parkinsonism. METHOD: Fifty-six subjects living with chronic schizophrenia between 50 and 75years of age underwent a motor evaluation along the original Unified Parkinson's Disease Rating Scale-section III and answered questions along the selected screening instruments, and results compared to those of 16 patients with Parkinson's disease (PD) and 15 neurologically unimpaired volunteers. Odds ratios, sensitivity, specificity, and their 95% confidence intervals, were calculated. RESULTS: All three screening instruments correctly identified the PD state and distinguished PD from healthy participants. Eighteen (32%) schizophrenic patients displayed objective motor signs of parkinsonism. A single item of the LUNSERS (shakiness) significantly distinguished DIP from DIP-free patients, with a sensitivity of 61.1% and a specificity of 83.3%. The positive predictive value was 63.5% and the negative predictive value was 81.9%. The two other screening methods showed insufficient predictive value. CONCLUSION: Apart from a single query on shakiness, none of the tools examined were adequate to screen for DIP in patients treated for schizophrenia. A different instrument is necessary to monitor this important adverse effect in schizophrenia.

INTRODUCTION Chronic snoring is considered abnormal in a pediatric population. This disorder is often attributed to enlarged tonsils and adenoids, but multiple anatomic obstructions should also be considered. Facial and dental morphometry associations with various sleep-disordered breathing symptoms were investigated at an orthodontic clinic. METHODS Parents or guardians were asked to complete a 4-part questionnaire on behalf of their children (n = 604; <18 years of age), including medical and dental history, bruxism and temporomandibular disorder habits, sleep and daytime behavior, and sleep duration and quality. All subjects underwent a clinical screening assessment by the same orthodontist to identify standard dental, skeletal, functional, and esthetic factors. RESULTS In contrast to sleep-disordered breathing or sleep apnea in adults, which is predominantly associated with obesity, sleep-disordered breathing symptoms in this pediatric cohort were primarily associated with adenotonsillar hypertrophy, morphologic features related to a long and narrow face (dolichofacial, high mandibular plane angle, narrow palate, and severe crowding in the maxilla and the mandible), allergies, frequent colds, and habitual mouth breathing. CONCLUSIONS Because of the recognized impact of pediatric snoring on children's health, the determination of these good predictors can help in preventing and managing sleep-disordered breathing. If a health professional notices signs and symptoms of sleep-disordered breathing, the young patient should be referred to a sleep medicine specialist in conjunction with an orthodontist if there are dentoskeletal abnormalities.

OBJECTIVES: The superiority of mandibular two-implant overdentures (IODs) over conventional complete dentures (CDs) in terms of quality of life is still questioned. Furthermore, the stability and magnitude of the treatment effect over time remain uncertain. This follow-up study aimed to determine the stability and magnitude of the effect of IODs on oral health-related quality of life (OHRQoL). MATERIAL AND METHODS: 172 participants (mean age 71 ± 4.5 years) randomly received CDs or IODs, both opposed by conventional maxillary dentures. OHRQoL was measured using the Oral Health Impact Profile (OHIP-20) at baseline, 1 and 2 years post-treatment. Repeated measures ANOVAs were conducted to assess the effects of time and treatment on the total OHIP and its individual domain scores. RESULTS: A statistically significant improvement in OHRQoL was seen for both treatment groups (P < 0.001). This improvement was maintained over the 2 year assessment. At both follow-ups, participants wearing IODs reported significantly better total OHIP scores than those wearing CDs (P < 0.001), with a 1.5 times larger magnitude of effect. In the CD group, baseline OHIP scores influenced the post-treatment scores (P < 0.001). This effect was not found in the IOD group. CONCLUSIONS: The effect of mandibular two-IODs on OHRQoL is stable over a 2-year period. The large magnitude of effect of this treatment supports its clinical significance.

OBJECTIVE: The mandibular advancement appliance (MAA) is now recognized as a first-line therapy option for mild to moderate obstructive sleep apnea syndrome (OSAS). The aim of this follow-up study was to re-assess the long-term efficacy of MAAs provided to patients in a previous comparative study. METHODS: Sixteen subjects had participated in a previous comparative study in which the efficacy and compliance of two MAAs (Klearway - K and Silencer - S) were compared in a randomized cross-over design. At the end of the previous comparative study, subjects selected the MAA they preferred. Nine chose the K and seven the S. Fifteen subjects were available for a follow-up interview and 14 (4 women and 10 men; mean±SEM: 51.9±1.7y.o.) agreed to participate in an overnight sleep recording at a hospital sleep laboratory from January to February 2009. The mean time lag between the end of the previous comparative study and the follow-up was 40.9±2.1months (range of 2.5-4.5years). Comparisons were made across the three polysomnographic evaluations (PSGE): baseline, the night with the appliance of their choice at the end of the previous comparative study, and the follow-up night. Subjects completed the Epworth sleepiness scale (ESS), the fatigue severity scale (FSS), and a quality of life questionnaire (FOSQ). RESULTS: At the follow-up, the respiratory disturbance index (RDI) remained significantly lower than baseline (p<0.001). Questionnaire responses revealed that ESS, FSS, and FOSQ remained improved at follow-up (p<0.02). Body mass index (BMI) increased slightly from baseline to follow-up (p<0.05). Diastolic and systolic blood pressure and cardiac rhythm decreased significantly from baseline to follow-up. CONCLUSIONS: The MAAs remained effective in improving RDI, sleepiness, blood pressure, cardiac rhythm, fatigue, sleep quality, and quality of life over a period of 2.5-4.5years. The rise in BMI is a concern that merits further examination.

Carra MC, Huynh N, Morton P, Rompré PH, Papadakis A, Remise C, Lavigne GJ. Prevalence and risk factors of sleep bruxism and wake-time tooth clenching in a 7- to 17-yr-old population. Eur J Oral Sci 2011; 119: 386-394. © 2011 Eur J Oral Sci Sleep-related bruxism (SB) and wake-time tooth clenching (TC) have been associated with temporomandibular disorders (TMDs), headache, and sleep and behavioral complaints. This study aimed to assess the prevalence and risk factors of these signs and symptoms in a 7- to 17-yr-old population (n = 604) seeking orthodontic treatment. Data were collected by questionnaire and by a clinical examination assessing craniofacial morphology and dental status. Sleep-related bruxism was reported by 15% of the population and TC was reported by 12.4%. The SB group (n = 58) was mainly composed of children (67.3% were ≤12 yr of age) and the TC group (n = 42) was mainly composed of adolescents (78.6% were ≥13 yr of age). The craniofacial morphology of over 60% of SB subjects was dental class II and 28.1% were a brachyfacial type. Compared with controls (n = 220), SB subjects were more at risk of experiencing jaw muscle fatigue [adjusted OR (AOR) = 10.5], headache (AOR = 4.3), and loud breathing during sleep (AOR = 3.1). Compared with controls, TC subjects reported more temporomandibular joint clicking (AOR = 5), jaw muscle fatigue (AOR = 13.5), and several sleep and behavioral complaints. Sleep- and wake-time parafunctions are frequently associated with signs and symptoms suggestive of TMDs, and with sleep and behavioral problems. Their clinical assessment during the planning of orthodontic treatment is recommended.

Aims: To evaluate the influence of an oral appliance on morning headache and orofacial pain in subjects without reported sleep-disordered breathing (SDB). Methods: Twelve subjects aged 27.6 ± 2.1 (mean ± SE) years and suffering from frequent morning headache participated in this study. Each subject was individually fitted with a mandibular advancement appliance (MAA). The first two sleep laboratory polygraphic recording (SLPR) nights were for habituation (N1) and baseline (N2). Subjects then slept five nights without the MAA (period 1: P1), followed by eight nights with the MAA in neutral position (P2), ending with SLPR night 3 (N3). Subjects then slept five nights without the MAA (P3), followed by eight nights with the MAA in 50% advanced position (P4), ending with SLPR night 4 (N4). Finally, subjects slept 5 nights without the MAA (P5). Morning headache and orofacial pain intensity were assessed each morning with a 100-mm visual analog scale. Repeated measures ANOVAs and Friedman tests were used to evaluate treatment effects. Results: Compared to the baseline period (P1), the use of an MAA in both neutral and advanced position was associated with a ⋝ 70% reduction in morning headache and ⋝ 42% reduction in orofacial pain intensity (P ⋜ .001). During the washout periods (P3 and P5), morning headache and orofacial pain intensity returned to close to baseline levels. Compared to N2, both MAA positions significantly reduced (P <.05) rhythmic masticatory muscle activity (RMMA). Conclusion: Short-term use of an MAA is associated with a significant reduction in morning headache and orofacial pain intensity. Part of this reduction may be linked to the concomitant reduction in RMMA. J OROFAC PAIN 2011;25:240-249.

Clinicians and investigators need a simple and reliable recording device to diagnose or monitor sleep bruxism (SB). The aim of this study was to compare recordings made with an ambulatory electromyographic telemetry recorder (TEL-EMG) with those made with standard sleep laboratory polysomnography with synchronised audio-visual recording (PSG-AV). Eight volunteer subjects without current history of tooth grinding spent one night in a sleep laboratory. Simultaneous bilateral masseter EMG recordings were made with a TEL-EMG and standard PSG. All types of oromotor activity and rhythmic masseter muscle activity (RMMA), typical of SB, were independently scored by two individuals. Correlation and intra-class coefficient (ICC) were estimated for scores on each system. The TEL-EMG was highly sensitive to detect RMMA (0·988), but with low positive predictive value (0·231) because of a high rate of oromotor activity detection (e.g. swallowing and scratching). Almost 72% of false-positive oromotor activity scored with the TEL-EMG occurred during the transient wake period of sleep. A non-significant correlation between recording systems was found (r = 0·49). Because of the high frequency of wake periods during sleep, ICC was low (0·47), and the removal of the influence of wake periods improved the detection reliability of the TEL-EMG (ICC = 0·88). The TEL-EMG is sensitive to detect RMMA in normal subjects. However, it obtained a high rate of false-positive detections because of the presence of frequent oromotor activities and transient wake periods of sleep. New algorithms are needed to improve the validity of TEL-EMG recordings.