Shorter Mandibular Length is Associated with a Greater Fall in AHI with Weight Loss.

RATIONALE: Obesity is a major risk factor towards the development of obstructive sleep apnea, while significant weight loss (both conservatively managed and surgically assisted) has a variable effect upon its severity. Differences in the effect of weight loss on obstructive sleep apnea may be due to underlying craniofacial characteristics. OBJECTIVES: To determine whether craniofacial characteristics can predict OSA treatment response to significant weight loss. METHODS: We analyzed craniofacial measurements from lateral cephalograms performed at baseline on 57 patients enrolled in a previously reported 2-year randomized clinical weight loss trial (laparoscopic adjustable gastric band surgery versus conservatively [dietician and very low calorie diet] treated). Group mean weight loss was ∼ 13% (mean weight loss 131 to 114 kg), with corresponding reduction in mean apnea-hypopnea index (AHI) from 61 to 41 events/h. Computer assisted lateral cephalogram analysis was undertaken by three trained staff blinded to treatment. We analyzed lateral cephalogram and demographic data at baseline (cross-sectional) and change over two years (interventional) in 54 patients. MEASUREMENTS AND MAIN RESULTS: Baseline cross-sectional analysis indicated no cephalometric measurement correlated significantly with baseline AHI when corrected for neck circumference. The percentage change in AHI over 2 years correlated with a shorter menton-gonion distance (i.e., mandibular body length). The % change in AHI correlated with the % weight change (R(2) = 0.25, p < 0.001) and mandibular body length (R(2) = 0.19, p = 0.002). The % change in AHI correlated with combined weight change and mandibular body length (combined R(2) = 0.31, p < 0.001). CONCLUSIONS: Weight loss as a therapeutic option for severe OSA with severe obesity may be predicted by shorter mandibular body length as measured by lateral cephalometry.

Effect of the smear layer on a pulp proximity-indicating instrument.

The purpose of the study was to determine the effect of removing or modifying the smear layer on the indication provided by the Prepometer pulp proximity-indicating instrument. Third molars were prepared to produce flat surfaces in the coronal dentine, and control Prepometer LED readings were made. Group E was treated with 18% EDTA and Group T with Tubulicid. Prepometer readings were repeated. Dentine was removed in 0.5 mm increments, and readings repeated until a red LED appeared, indicating a danger of pulp exposure. Distances to the pulp were measured. t test, Wilcoxon signed ranks test (WSR) and ordinal regression (OR) analysis were performed, together with SEM examination. There were significant differences between both test groups and their untreated controls. OR showed that a red LED appeared further from the pulp with EDTA treatment than with no treatment. A red LED appeared closer to the pulp with Tubulicid treatment than with no treatment. SEM showed smear removal in Group E and occlusion of tubules in Group T. Prepometer performance was significantly influenced by treatment with EDTA and Tubulicid. Practitioners would be required to learn to interpret the display of the Prepometer instrument in the context of the tooth under treatment and the surface condition of the cut dentine.

A novel instrument to determine pulp proximity.

The aim was to determine whether extracted teeth could be used to test the Prepometer instrument, which indicates pulp proximity with green/amber/red light emitting diodes. Third molars were reduced to a plane in dentine and Prepometer readings made. Dentine was removed in 0.5 mm increments and readings made until only lights 9 or 10 (red) showed. The teeth were sectioned and the dentine thickness measured. Analysis permitted construction of a highly significant predictor-model (p < 0.01), the red/amber light boundary coinciding with a dentine thickness of 2.4 mm. The Prepometer was consistent in predicting pulp proximity but was more sensitive than specified.

Prevalence and risk of traumatic gingival recession following elective lip piercing.

The aims of this study were to evaluate the prevalence, risk and odds ratios of gingival recession defects associated with elective lip piercing and wearing of stud jewelry, and to attempt to identify risk factors that might permit the incidence of recession and its severity to be predicted, using Miller's classification. Ninety-one subjects with lip piercing and labrets were evaluated with regard to gender, age, smoking history, orthodontic history, and labret characteristics. An age-matched group of 54 individuals without peri-oral piercing provided the control. Gingival recession was recorded on teeth opposing a labret in 68.13% of pierced subjects. By contrast, only 22.2% of unpierced individuals demonstrated recession. The odds ratio between pierced and control groups indicates a likelihood of recession 7.5 times greater in a pierced individual wearing a labret than in an unpierced individual. Logistical regression analysis showed that age, gender, smoking and labret configuration did not significantly influence the development of recession. Furthermore, an illustrative example indicates that piercing and provision of a labret might typically increase the risk of recession occurring from 34.4% (pre-piercing) to 80.8 %. Recession severity was greater in the pierced group, with Miller's class 2 and 3 defects observed in 18.7% of the pierced but not at all in the unpierced group. Ordinal regression identified previous orthodontic treatment as the only significant predictor of Miller's grade. We concluded that a clear link exists between lip piercing, labret use and gingival recession. Belief that labret placement and configuration can be modified to provide protection is unfounded.

Radiographic recognition and distribution of approximal carious lesions in New Zealand undergraduate dental students.

Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The aim of this study was to determine the prevalence of approximal caries in an educated young adult (New Zealand dental student) population, and to compare the diagnostic decisions of students and university teachers. A total of 123 students aged from 18 to 25 years (mean age 21 years) participated, having given their informed consent. Their bitewings were digitised and assessed for approximal carious lesions from the distal surface of the first premolars to the mesial surface of the second molars on the same computer screen. The following criteria were used: (0) no detectable radiolucency, (R1) lesion confined to the outer half of the enamel, (R2) lesion into the inner half of the enamel, (R3) lesion into the outer half of dentine along the amelodentinal junction, (R4) lesion beyond the outer part of the dentine. The views were assessed by two final-year dental students and two experienced university teachers, and results were compared. A total of 2710 surfaces were examined; restored and missing surfaces (tooth absent, off film or surface unreadable) were excluded. Carious lesions were found in 173 (6.38 percent) of the surfaces. Only 57 subjects presented with carious lesions radiographically, but 16 (13 percent) of subjects had 87 percent of all the lesions. Seventy-nine percent of the lesions were enamel lesions (R1 and R2), with 21 percent of the lesions having dentine involvement (R3 and R4). Inter-examiner agreement was high, Pearson's correlation coefficient r = 0.8237, and Cohen's kappa kappa = 0.76.

Altered jaw posture and occlusal disruption patterns following mandibular advancement therapy for sleep apnea: a preliminary study of cephalometric predictors.

PURPOSE: Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships in individuals using mandibular advancement devices for obstructive sleep apnea are beginning to appear. This study sought cephalometric means of identifying such individuals before commencing therapy. MATERIALS AND METHODS: Cephalograms of 34 obstructive sleep apnea sufferers who had worn mandibular advancement devices for 2 years were compared retrospectively with baseline films taken at commencement of therapy and analyzed for signs of morphologic changes in jaw position and occlusal relationship. In affected patients, two distinct morphologic species of mandibular reposturing became evident: (1) bilateral posterior open bite with destructive incisal attrition; and (2) less destructive intermediate open bite over the premolar and first molar regions. From the observed morphology patterns, gonial angle and maxillary-mandibular plane angle were analyzed as possible vertical cephalometric risk predictors, with newly defined pterygoid advancement proportion (PtAP) as a horizontal predictor. RESULTS: Three patients displayed the posterior open bite pattern and had gonial angles < or = 119 degrees and maxillary-mandibular plane angles < or = 16 degrees, with PtAP values > or = 0.48. Prediction intervals for the five intermediate open bite cases were 118 degrees < or = gonial angle < or = 128 degrees, and 23 degrees < or = maxillary-mandibular plane angle < or = 32 degrees. PtAP values were > or = 0.52. CONCLUSION: Cephalometric analysis can help practitioners identify which apnea patients might be likely to develop irreversible mandibular postural changes from wearing a jaw-repositioning device.