Glenn T. Clark

The effects of 1-year treatment with a herbst mandibular advancement splint on obstructive sleep apnea, oxidative stress, and endothelial function.

BACKGROUND Obstructive sleep apnea (OSA) is associated with endothelial dysfunction. In the current study, we assessed the effect of long-term modified Herbst mandibular advancement splint (MAS) treatment on OSA, oxidative stress markers, and on endothelial function (EF). METHODS A total of 16 subjects participated (11 men and 5 women; mean [+/- SD] age, 54.0 +/- 8.3 years; mean body mass index, 28.0 +/- 3.1 kg/m(2)), 12 of whom completed the 1-year evaluation. Apnea severity, levels of oxidative stress markers, and EF were assessed after 3 months and 1 year of receiving treatment. For comparison, 6 untreated patients underwent two evaluations 9 months apart, and 10 non-OSA individuals were assessed once as a reference group. The results are presented as the mean +/- SD. RESULTS The mean apnea-hypopnea index (AHI) decreased significantly from 29.7 +/- 18.5 events/h before treatment to 17.7 +/- 11.1 events/h after 3 months of treatment and 19.6 +/- 11.5 events/h after 1 year of treatment (p < 0.005 for both). The mean Epworth sleepiness scale score decreased significantly from 12.4 +/- 6.0 before treatment to 10.2 +/- 6.6 after 3 months of treatment and 7.8 +/- 3.8 after 1 year of treatment (p < 0.001 for both). The mean EF improved significantly from 1.77 +/- 0.4 before treatment to 2.1 +/- 0.4 after 3 months of treatment (p < 0.05) and 2.0 +/- 0.3 after 1 year of treatment (p = 0.055), which were similar to the values of the reference group. Thiobarbituric acid-reactive substance (TBARS) levels decreased from 18.8 +/- 6.2 nmol malondialdehyde (MDA)/mL before treatment to 15.8 +/- 3.9 MDA/mL after 3 months of treatment (p = 0.09) and 15.5 +/- 3.2 nmol MDA/mL after 1 year of treatment (p < 0.05). There was a correlation between the improvement in AHI and in EF or TBARS levels (r = 0.55; p = 0.05). The untreated control group remained unchanged. CONCLUSIONS The Herbst MAS may be a moderately effective long-term treatment for patients with OSA. EF improved to levels that were not significantly different than reference levels, even though apneic events were not completely eliminated. We think that these data are encouraging and that they justify the performance of larger randomized controlled studies.

Treatment outcomes of mandibular advancement devices in positional and nonpositional OSA patients

OBJECTIVE The aim of the study was to investigate treatment outcome of mandibular advancement devices (MADs) for positional and nonpositional obstructive sleep apnea (OSA). STUDY DESIGN Forty-two positional (supine apnea-hypopnea index [AHI] > or = 2 times lateral AHI) and 30 nonpositional (supine AHI < 2 times lateral AHI) OSA patients performed 2-nights of sleep study before and after insertion of MADs. RESULTS The decreases in apnea severity based on a reduction in the overall and supine AHI values after MADs therapy were significantly greater for the positional OSA than nonpositional OSA group. A multiple linear regression analysis showed that decrease in overall AHI was significantly associated with being in the positional group (standardized coefficient = 0.505). Age, body mass index, gender, and time in supine position during sleep did not show significant associations with decrease in overall AHI after MAD therapy. CONCLUSION Our data suggest that MADs are more effective in positional OSA than nonpositional OSA patients.

Association of genetic, psychological and behavioral factors with sleep bruxism in a Japanese population.

Sleep bruxism is a sleep‐related movement disorder that can be responsible for various pains and dysfunctions in the orofacial region. The aim of the current case–control association study was to investigate the association of genetic, psychological and behavioral factors with sleep bruxism in a Japanese population. Non‐related participants were recruited and divided into either a sleep bruxism group (n = 66) or control group (n = 48) by clinical diagnoses and 3‐night masseter electromyographic recordings by means of a portable miniature device. The Epworth Sleepiness Scale, Temperament and Character Inventory, NEO‐Five Factor Inventory and custom‐made questionnaires that asked about familial aggregation, alcohol intake, caffeine intake, cigarette smoking, past stressful life events, daytime tooth‐contacting habit, temporomandibular disorder, daily headache, snoring, apnea/hypopnea symptoms, leg‐restlessness symptoms and nocturnal‐myoclonus symptoms were administered. In addition, 13 polymorphisms in four genes related to serotonergic neurotransmission (SLC6A4, HTR1A, HTR2A and HTR2C) were genotyped. These factors were compared between case (sleep bruxism) and control groups in order to select potential predictors of sleep‐bruxism status. The statistical procedure selected five predictors: Epworth Sleepiness Scale, leg‐restlessness symptoms, rs6313 genotypes, rs2770304 genotypes and rs4941573 genotypes. A multivariate stepwise logistic regression analysis between the selected predictors and sleep‐bruxism status was then conducted. This analysis revealed that only the C allele carrier of HTR2A single nucleotide polymorphism rs6313 (102C>T) was associated significantly with an increased risk of sleep bruxism (odds ratio = 4.250, 95% confidence interval: 1.599–11.297, P = 0.004).This finding suggests a possible genetic contribution to the etiology of sleep bruxism.

Effects of mandibular advancement on upper airway dimension and collapsibility in patients with obstructive sleep apnea using dynamic upper airway imaging during sleep

OBJECTIVES The objective of this study was to evaluate the effects of mandibular advancement on oropharyngeal dimension and collapsibility and reveal the predominate site of change produced by mandibular advancement in patients with obstructive sleep apnea (OSA). STUDY DESIGN Sixteen adults (13 males and 3 females) with symptomatic mild to severe OSA participated. Custom-made silicone mandibular positioners were used to keep the mandible at 67% of maximum advancement. Changes in the oropharyngeal size and collapsibility with mandibular advancement were evaluated using ultrafast computed tomography taken during wakefulness and midazolam-induced sleep. Cross-sectional areas were assessed using electron beam tomography at 4 levels: high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). RESULTS During sleep, the minimum cross-sectional areas decreased 36.5%, 67.8%, 75.5%, and 65.8% at each level of HRP, LRP, HRG, and LRG respectively, as compared with those measured during wakefulness. Mandibular advancement during sleep increased 75.7%, 141.3%, 128.1%, and 119.9% at each level. The oropharynx showed 70.3%, 110.4%, 140.3%, and 156.9% increase in the Collapsibility Indices during sleep at each level of HRP, LRP, HRG, and LRG, respectively, compared with wakefulness. However, collapsibility indices decreased 29.1%, 23.2%, 21.4%, and 34.1% at each level with mandibular advancement. CONCLUSION Mandibular advancement increases oropharyngeal diameter and decreases oropharyngeal collapsibility during midazolam-induced sleep respiration at the retropalatal as well as the retroglossal region in most patients with OSA.

Occlusal dysesthesia: a qualitative systematic review of the epidemiology, aetiology and management.

Occlusal dysesthesia refers to a persistent complaint of uncomfortable bite sensation with no obvious occlusal discrepancy. This systematic review aimed to draw a picture of such patients, to present an agreement of previously reported diagnostic criteria and to analyse the evidence level of the recommended management approaches. An electronic search for all relevant reports on occlusal dysesthesia was thoroughly performed based on previous nomenclatures (e.g. phantom bite, occlusal hyperawareness) in PubMed and The Cochrane Library in July, 2011. A total of 84 reports were matched, among which only 11 studies were included after a two-step (abstract and detailed full-text revision) screening process. Additionally, a thorough manual review of reference lists of the included reports enabled the inclusion of two additional studies. Data analysis revealed that 37 occlusal dysesthesia patients presented a mean age of 51.7 ± 10.6 years and were predominantly women (male/female: 1/5.1) with symptom duration of more than 6 years (average: 6.3 ± 7.5 years) and with concomitant psychological disturbances (e.g. mood disorders, somatoform disorders, personality disorders). Only four authors presented diagnostic criteria for occlusal dysesthesia, which served as the basis for an agreement in the diagnostic criteria. Treatment approaches included psychotherapy, cognitive/behaviour therapy, splint therapy and prescription of anti-depressants or anti-anxiety drugs. Classification of evidence level of management approaches, however, revealed that most of them were expert opinions with single- or multiple-case report(s). Future studies are necessary for a deeper understanding of the mechanisms behind the occlusal dysesthesia symptoms, and consequently, for improvements in evidence-based management approaches.

Soft palate length and upper airway relationship in OSA and non-OSA subjects

BACKGROUND The narrowest area of the airway between the posterior nasal opening and the epiglottis is usually located in the retro palatal area. Many consider this the most likely site of airway obstruction during an obstructive sleep apnea (OSA) event. The aim of this study was to investigate the differences in soft palate and airway length between OSA and non-OSA patients. METHODS In this study, we analyzed the ratio of the soft palate and the upper airway length in 45 consecutive patients. Twenty-five had an Apnea-Hypoapnea Index of more than five events per hour and were classified in the OSA group (male, 19; female, 6). These patients were compared with 20 normal controls (male, 12; female, 8). Controls who complained of snoring did have sleep studies (n=5). The other fifteen controls were clinically asymptomatic and did not have sleep studies. Medical computed tomography scans were taken to determine the length of the upper airway and the soft palate length measured in the midsagittal image. RESULTS Soft palate length was significantly larger in OSA patients compared to controls (p=0.009), and in men compared to women (p=0.002). However, there were no differences in airway length. The soft palate length, as a percent of oropharyngeal airway length, was significantly larger in OSA patients compared to controls (p= <0.0001) and in men compared to women (p=0.02). Soft palate length increases significantly with age by 0.3 mm per year in males (after adjustment for body mass index (BMI) and OSA). Soft palate length as a percent of airway length is larger in OSA patients and increases significantly with BMI in males only after adjusting for age. CONCLUSION In this study, OSA patients had a longer soft palate in proportion to their oropharyngeal airway compared to controls as well as men compared to women. This proportion could be used for identifying patients at risk for OSA in combination with age.

Classification, causation and treatment of masticatory myogenous pain and dysfunction.

This article focuses on chronic myogenous pains affecting the masticatory muscles, including focal myalgia, regional myalgia, myofascial pain, and fibromyalgia. The probable mechanisms are discussed and treatment options, including self-directed treatment, physical medicine modalities, and several types of pharmacologic agents, are presented.

Is p16-positive oropharyngeal squamous cell carcinoma associated with favorable prognosis? A systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to compare the prognosis of patients with p16 expressing oropharyngeal squamous cell cancers to patients with p16 non-expressing cancers. Clinical outcomes that were evaluated included overall survival, local recurrence, disease-free survival, disease-specific survival, and event-free survival. The following electronic databases were searched: Cochrane Library, MEDLINE (via Pubmed), and Web of Science. Publications were restricted to English language. Studies were limited to controlled clinical trials on the survival rates of patients with oropharyngeal tumors that were p16 expressing, compared to patients with p16 non-expressing tumors, and at least one clinical endpoint reported by trial authors (hazard ratios). Specific ascertainment criteria were applied for inclusion and exclusion of eligible studies. Data was independently extracted in duplicate. This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analysis PRISMA checklist. Risk of bias was assessed for all included studies, and disagreements between review authors were discussed until an agreement was reached. Eighteen studies were included for final review and meta-analysis. The subgroup meta-analyses, which included survival and recurrence data, showed significantly favorable outcomes for patients with p16 expressing tumors. There is strong evidence to support that patients with p16 expressing oropharyngeal squamous cell cancers have favorable clinical outcomes and prognosis.

Comparing the Berlin and the ARES questionnaire to identify patients with obstructive sleep apnea in a dental setting

PurposeThe aim of this study was to compare the sensitivity and specificity of two questionnaires to identify patients with obstructive sleep apnea (OSA).Materials and methodsFifty-three moderate to severe OSA patients [with a respiratory disturbance index (RDI) ≥ 15] and 31 controls (RDI < 15) based on ambulatory somnographic assessment were recruited through flyers and mail at USC School of Dentistry. Each patient answered the Berlin and apnea risk evaluation system (ARES) questionnaires. The responses to the questionnaires were scored and compared for significant group differences.ResultsModerate and severe OSA patients were predominantly male, older, had a larger neck size, and larger body mass index than controls. There were no significant differences in race or ethnicity between the two groups. In this study, subjects having a “high risk” ARES questionnaire were 7.9 times as likely to have OSA as subjects with “low or no risk” score (p = 0.0002). The ARES questionnaire had a sensitivity of 90.6%, specificity of 43.2%, a positive predictive value (PPV) of 73.8%, and negative predictive value (NPV) of 73.7% compared to 67.9%, 54.8%, 72%, and 50%, respectively, for the Berlin questionnaire using a cut point of RDI ≥ 15.ConclusionsIn this specific patient group, not uncommon to the regular dental private practice, the ARES questionnaire performed better than the Berlin questionnaire with higher sensitivity, similar PPV, higher NPV, but lower specificity. The lower specificity could be explained in part because the ARES has been tailored to screen patients with an RDI ≥ 5, and our study included mostly mild to severe patients. In conclusion, in this specific group of subjects, the ARES questionnaire is a better choice than the Berlin questionaire; however, the Berlin questionnaire is publicly available and the ARES screener is proprietary.

Correlation between retroglossal airway size and body mass index in OSA and non-OSA patients using cone beam CT imaging

Most obstructive sleep apnea (OSA) patients are overweight, and OSA is substantially more common in obese individuals. In morbidly obese patients, at least 70% suffer from OSA. However, the exact mechanism by which obesity causes OSA is unclear. The aim of this study is to evaluate the retroglossal airway configuration quantitatively and to make clear the relationship between Body mass index (BMI) and airway configuration. This retrospective study included 15 OSA patients (male = 11; female = 4) and 14 normal controls (male = 8; female = 6). We studied the airway configuration on an axial slice at the level of the anterior–inferior corner of the second cervical vertebra. Maximum anterior–posterior diameter (AP) and lateral width (LW) of the airway were measured, and the square area (SA) was calculated. The airway cross-section area (AWA) was also measured, and then the AWA/SA ratio was calculated. AP, LW, and AWA were not statistically significantly different between controls and OSA patients. On the other hand, the AWA/SA ratio in OSA patients was 8.8% statistically significantly smaller than in controls after adjusting for sex, age, and BMI. In this sample, there was a negative correlation between age and the AWA/SA ratio but only in the OSA group. The AWA/SA ratio was significantly negatively correlated with OSA status (R = −0.5; p = 0.008) after adjusting for BMI and age. In this present study, we could evaluate the retroglossal airway configuration quantitatively. The AWA/SA ratio was correlated with OSA status after adjusting for BMI and age.