Introduction
Mandibular Advancement Devices (MAD) have been reported to be an alternative treatment to CPAP in moderate to severe obstructive sleep apnea (OSA) cases. The design of MAD has a major influence on its success rate on the patient, and design features that have an influence on efficacy, tolerance, and compliance. The aim of this study was to determine the range of mandibular protrusion at different vertical points; 2, 5, 8 and 11 mm in a young adult population.
Methods
Fifty two students aged 19 to 23 years (mean 21.3 ± 1.7; 29 females and 23 males), with full permanent dentition participated in the study. The absolute range of maximal mandibular protrusion and retrusion was measured (mm) with the use of the George Gauge. Descriptive statistics, ANOVA and paired t-test using SPSS were used.
Results
Range of mandibular advancement was possible to be determined for the 4 levels of vertical opening with the gauges: 2 mm fork mean mandibular advance 13,10 mm ± 0.604; 5 mm mean 11.98 mm ± 1.075; 8 mm mean 11.20 mm ± 1.369; 11 mm mean 9.87 mm ± 1.886. No significant differences were found between class I, II, and III.
Conclusions
There is an impact of increased inter-incisal distance of effective mandibular protrusion when constructing a MAD. As vertical dimension increases the mandible rotates posteriorly and places itself in a more retrusive location, and the range of mandibular advancement reduces (0.3 mm for every 1 mm of vertical increase).
Background: The aim of this study was to compare the shear bond strength (SBS) of a flash-free and precoated orthodontic adhesive with a compomer orthodontic adhesive before and after thermocycling. The adhesive remnant index (ARI) was also determined for both adhesives. Material and Methods: A total of 120 human premolars were randomly divided into two groups (n=60) according to the orthodontic adhesive used: APC Flash-Free Adhesive Coated Appliance System (APC FF) or Transbond PLUS Color Change Adhesive (TP), as control. Then three subgroups were established according to the aging procedure: water storage (37ºC, 24h), thermocycling for 10,000, or 20,000 cycles. A SBS test was performed and ARI value for each specimen was also assessed. Results were analyzed by two-way ANOVA and Tukey's Chi-square test (p < 0.05). Results: SBS values were significantly influenced by thermocycling (p < 0.01). Neither the orthodontic adhesive nor the interaction between adhesive and thermocycling statistically affected SBS results (p > 0.05). Conclusions: APC FF and TP showed similar bond strength results. Thermocycling induced a significant decrease in SBS values for the two adhesives tested, without differences between 10,000 and 20,000 thermal cycles. Moreover, APC FF left less adhesive remnants on the enamel compared to TP.
The aim of this study was to determine and compare the visual accuracy of students and experienced orthodontists in distinguishing the different skeletal classes and facial biotypes using only lateral photographs. A group of 19 orthodontic students (4 males and 15 females, aged between 23 and 30 years) and 9 experienced orthodontists (three males and six females, aged between 30 and 56 years) were shown a slide presentation of 100 (50 males and 50 females) patients aged between 8 and 42 years and were asked to indicate the skeletal class and the facial biotype of each subject. Data were analysed using a one-way repeated measures analysis of variance, with Bonferroni post hoc adjustment for multiple testing. P-values less than 0.05 were considered statistically significant. Only 32.75 per cent of the participants identified the facial biotype of the patients with respect to Rickett's vertical (Vert) pattern and 47.96 per cent the skeletal class. The students performed better than the experienced orthodontists (P < 0.05) but only for skeletal class. The results indicate that lateral photographs are not sufficient for determining the skeletal class or facial biotype of patients.
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