Neda Eslami; Farid Sharifi; Athar Nasseri; Arezoo Jahanbin
Abstract
Background: There is great controversy regarding the effect of MBT and Damon bracket systems on dental arch dimensions and incisor position.
Objectives: We aimed to study the effects of two different brackets (MBT and Damon) on dental arch dimensions and incisors position after orthodontic treatment.
Methods: ...
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Background: There is great controversy regarding the effect of MBT and Damon bracket systems on dental arch dimensions and incisor position.
Objectives: We aimed to study the effects of two different brackets (MBT and Damon) on dental arch dimensions and incisors position after orthodontic treatment.
Methods: In this retrospective study, the records of 20 patients who underwent orthodontic treatment with MBT or Damon bracket systems were studied. All patients had class I skeletal and dental malocclusion and were treated without extraction. The patients were treated either with Damon or MBT bracket systems (n = 10). Lateral cephalograms were traced using the Dolphin software to determine the position of incisors. In addition, transverse dimensions of dental arches were measured on occlusal photographs. Fishers’ exact test, independent-test, Man-Whitney, paired t-test, and Wilcoxon were used for statistical analysis. P < 0.05 was set as significant.
Results: There was no significant difference between the two groups regarding age, sex, and initial values of the variables studied. U1-Apog (mm), upper inter-canine, lower inter-second premolar distance showed a significant difference before and after treatment in the Damon system. However, no significant difference was observed between initial and post-treatment values in the MBT group. L1-Apog (°), IMPA (°), maxillary inter-first and second premolars, inter-canine, and mandibular inter-canine distance was higher in the Damon system after treatment compared to MBT. Changes of the upper and lower transverse dimensions of the dental arches and the incisor positional did not reveal a notable difference in the Damon and MBT systems (P > 0.05).
Conclusions: There was no significant difference regarding changes in dental arches and incisor positions between the Damon and MBT systems.
Abdolrahim Davari; Soghra Yassaei; Mahdjoube Goldani Moghadam; H. Zoghi
Abstract
Aim: The objective of this study was to determine the effect of thermocycling on shear bond strengths (SBSs) of a light cured compositeafterdifferent thermal cycles.Materials and methods: 80 Bovine incisors were randomly divided into 4 groups of 20 teeth. Each teeth were etched with 37% phosphoric acid ...
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Aim: The objective of this study was to determine the effect of thermocycling on shear bond strengths (SBSs) of a light cured compositeafterdifferent thermal cycles.Materials and methods: 80 Bovine incisors were randomly divided into 4 groups of 20 teeth. Each teeth were etched with 37% phosphoric acid and brackets were bonded using a light cured composite (Resilience). Thermocycling was done between 5° C and 55° C for 500, 3000 and 6000 cycles in group 2,3 and 4 respectively. Teeth in group1 (control group) were not being thermocycled. The SBS values were measured by means of Dartec testing machine.
Results: The results showed significantly higher SBS values for the control group compared to test groups (2-3 and 4). No significant different was observed between test groups.
Conclusion: Thermal changes during thermocycling significantly reduce the mean SBS of conventional etch and rinse adhesive system (Resilience), but SBS in 500, 300 and 6000 cycles had no significant difference. Clinical significance: Alteration in values of shear bond strengths under thermocycling would be representative of expected behavior of orthodontic brackets in clinical situations.
