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Background and objective:This study aimed to determine the prevalence, size, shape and location of tori in partially and completely edentulous patients attending the College of Dentistry/ Hawler Medical University from 2009-2011. Methods: In a retrospective study four hundred and fifty patients case file from Erbil city were examined for the presence of oral tori in prosthodontic department, College of Dentistry, Hawler Medical University. The size, shape and location of tori were recorded and related with the age and sex of patients. Results: The overall prevalence of tori was 14.2% (64 cases). The prevalence of torus palatinus was 60.9% (39/64), while that of torus mandibularis was significantly lesser 23.5 % (15/64).Both types of tori were associated with each other in 15.62% of cases (10/64). Conclusion:There was no statistically significant difference in the prevalence of tori between males and females. There was a significant relationship between the presence of mandibular and palatal tori.

Objective: This study aimed to evaluate the effect of adding titanium dioxide nanoparticles (TiO2NPs) on Shore A hardness, Young’s modulus, and tear strength of alginate impression material. Methods: Each test consists of one control group (alginate without TiO2NPs), and three test groups (2%, 3%, and 5%) of TiO2NPs were added, respectively. For each group, seven samples were constructed. For Shore A hardness, the samples were prepared according to ISO standards (7619-1:2010); Young’s modulus was calculated from the obtained Shore A hardness value according to a special standard equation. In contrast, for tear strength, the samples were prepared according to ASTM D 624-00. Results: The Control group exhibited a significantly less Shore A hardness value than all the other groups except the group that contained 2% TiO2NPs, where the increase in the hardness value was non-significant. A similar result was observed for Young’s modulus test, where the addition of TiO2NPs significantly increased Young’s modulus compared to the control group. Although, on the contrary, the tear strength was significantly improved by adding 3% TiO2NPs compared to control and other groups, there was a significant drop in the value of tear strength when 5% TiO2NPs were added to alginate. Conclusions: The addition of 3% TiO2NPs to dental alginate increased Shore A hardness, Young’s modulus, and significantly improved tear strength.

Background and objectives: determine the causes and types of complete denture fractures. Methods: The study was performed in the Hawler medical university, college of Dentistry Department of Prosthodontics. The number of fractured complete denture collected was 290 from patients aged 35-80 years of both genders. The (causes of denture fracture, the type of fracture and the history of previous recurrent fractures) were recorded. Results: : The main cause of denture fracture was poor fitting (40%), followed by poor occlusal relation (21%). Midline fracture was the commonest type of fracture (59%). From the study (51%) of the dentures had previously been repaired once or more. The ratio of lower to upper complete denture fractures was approximately 3:1; most of the fractured dentures (56%) were those of males. Conclusion: The causes of the fracture were divided into material factors and clinical/ technical factors. Denture fractures can be reduced by following prosthodontic principles, analyzing proper fit, eliminating occlusal interferences and using high impact polymers or metal reinforced.