Evaluation of undergraduate dental students in typodont preparation for all-ceramic crowns

Background: All-ceramic crown (ACC) preparations are widely used in day-to-day dentalclinical practice. Objectives: This study aimed to evaluate all-ceramic crown preparationsperformed by pre-clinical dental students at the College of Dentistry, Jazan University inSaudi Arabia and to compare the quality of the preparations between male and female groups.Materials and Methods: A total of 95 ivory teeth were prepared by fourth-year dentalstudents (44 males, 51 females). The students prepared a maxillary right central incisor forACC after mounting in the Frasaco typodont arches. Two silicone putty indexes for maxillaryanterior were obtained that extended to cover one or two teeth on either side. The facial indexwas used to provide information about the facial reduction mesio-distally. Another index wasprepared by cutting the silicone in half along the faciolingual midline of the prepared tooth,providing us with incisal, buccal, palatal, and axial reductions, in addition to biplanereduction. The data were encoded into a Statistical Package for Social Sciences program andanalyzed accordingly using Chi-square test. Results: The preparations of ACC for maxillaryanterior teeth were acceptable, ranging within 60%-85% in all criteria, which includedstructural durability, retention, and resistance. The male group was more excellent in incisalreduction (41.0%), whereas the female group was more excellent in axial taper preparations(59.1%), resulting in significant differences between genders in this preparation criteria. Allgender groups showed acceptable tooth preparations in shoulder reductions and location offinish lines, ranging within 57%-89%. Conclusion: The preparations for ACC achieved bythese dental students were considered clinically acceptable. The students clearly understoodthe principles of crown preparation. However, they still require more practice in order tomaster the art of crown preparation.

The Effects of 5-HTR1A Polymorphism on Cingulum Connectivity in Patients with Panic Disorder

OBJECTIVE: Serotonin-1A receptors (5-HTR1A) is suggested to be involved in the etiology of several psychiatric disorders including panic disorder (PD). A few imaging studies have suggested the alterations of the cingulum bundle in PD. The objective of this study is to examine the structural changes of cingulum related to the 5-HTR1A polymorphism rs6295 in the patients with PD. METHODS: Thirty-two right-handed patients with PD [11 men, 21 women; 40.34+/-13.17 (mean+/-SD) age] who met the diagnostic criteria in Structured Clinical Interview for DSM-IV were examined by means of MRI at 3 Tesla. We divided the patients with PD into CC genotype group and non CC genotype group (GG/CG genotype group) of the 5-HTR1A rs6295 polymorphism to compare the cingulum white matter connectivity. RESULTS: Tract-based spatial statistics showed significantly increased fractional anisotropy (FA) values in cingulate gyrus process of left cingulum in 5-HTR1A CC genotype compared to GG/CG genotype in PD. Significant positive correlations were shown between the Albany Panic and Phobia Questionnaire (APPQ) interoceptive fear subscale scores, the Anxiety Sensitivity Inventory-Revised fear of publicly observable anxiety reaction subscale scores and FA values of cingulate gyrus process of left cingulum in 5-HTR1A rs6295 GG/CG genotype group. In CC genotype group, APPQ total, APPQ agoraphobia subscale and APPQ social phobia subscale scores also showed significant positive correlations with FA values of hippocampal process of right cingulum. CONCLUSION: This preliminary study suggests that 5-HTR1A polymorphism may be associated with the cingulum white matter connectivity in PD.