ABSTRACT
Objective: Increased enamel surface roughness following orthodontic bracket debonding leads to increased plaque accumulation and enamel decalcification. Therefore, different methods are employed to achieve smoother enamel surfaces after bracket debonding. This study compared enamel surface roughness following orthodontic bracket debonding and composite resin removal using white stone and tungsten carbide burs
Methods: In this in-vitro, experimental study, 20 first and second premolars of 10-20 year-olds were collected and their crowns were mounted in acrylic blocks. Roughness of the buccal surfaces of teeth was determined by atomic force microscopy [AFM] and the brackets were bonded to the teeth. After bracket debonding, composite remnants were removed using white stone and tungsten carbide burs. Parameters of enamel surface roughness were determined by AFM and time required for composite removal was also calculated. Repeated measures ANOVA was used to assess the changes in parameters based on the time of measurement, type of bur and their interaction effect. Time required for composite resin removal by bur was analyzed using one-way ANOVA and Tukey's multiple comparisons
Results: Resin removal increased enamel surface roughness compared to the baseline values in all groups. However, no significant differences were noted between the two types of burs regarding arithmetic average of the roughness profile [Ra], the root mean square roughness [Rq] and the maximum peak-to-valley height in the sampling length [Rt] after resin removal. Time required for resin removal with tungsten carbide bur [34.2 seconds] was significantly shorter than with white stone bur [56.6 seconds][both ps<0.0001]
Conclusion: Considering the similar enamel surface roughness values achieved by the two burs, tungsten carbide burs are recommended for resin removal following orthodontic bracket debonding
ABSTRACT
The relationship between IQ score and malocclusion is a subject that has been the focus of attention in the field of orthodontics. The present study aimed at determining the IQ score of patients with dentoskeletal malocclusions presenting to the Orthodontic Department of Shahid Beheshti Dental School during 2008-2009. This descriptive cross-sectional study was conducted on 160 patients aged 12-18 yrs. who were receiving orthodontic treatment. A questionnaire was designed containing 3 sections of demographic characteristics, general information and orthodontic treatment. The questionnaire was completed by the patient and senior dental students and patients were asked to take the Cattell Culture Fair III IQ test on the computer and the obtained IQ score was recorded. Data were analyzed using linear regression analysis. The mean IQ score of the understudy population was 98 +/- 16. IQ score had a significant correlation with level of education [P<0.001], age [P<0.001] and socioeconomic status [P<0.001]. However, type of skeletal malocclusion and facial growth pattern were not correlated with the IQ score. The obtained results showed no association between type of skeletal malocclusion or facial growth pattern and the IQ score