Esfandiar Akhavan Niaki; Masomeh Esmaily; Yasamin Farajzadeh Jalali
Abstract
Background: Bonding is the most commonly used technique to attach brackets to tooth surfaces.
Objectives: The aim of this study was to determine the effects of time and concentration of etching with phosphoric acid on shear bond strength (SBS) of orthodontic brackets after using 10-MDP containing adhesive.
Methods: ...
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Background: Bonding is the most commonly used technique to attach brackets to tooth surfaces.
Objectives: The aim of this study was to determine the effects of time and concentration of etching with phosphoric acid on shear bond strength (SBS) of orthodontic brackets after using 10-MDP containing adhesive.
Methods: Fifty intact premolars were randomly divided into 5 groups (n = 10). They were mounted in resin blocks. In control group a gel without phosphoric acid and in-group 2, 3, 4, and 5, phosphoric acid 37% for 5 or 15 seconds and phosphoric acid 15% for 5 or 15 seconds was used respectively. Clearfil SE Bond was used as an adhesive resin for all samples. After bonding of brackets, they were put under 300 thermocycling aging regime and after that the bracket/tooth SBS was measured by universal testing machine. The adhesive remnant index (ARI) was evaluated under a stereomicroscope. Data were statistically analyzed using two-way ANOVA and Kruskal-Wallis test. Results: The highest mean SBS belonged to the 15% phosphoric acid etching in 15 seconds while the lowest value was seen in 37% phosphoric acid etching in 5 seconds. The effect of etching time on SBS was not significant (P = 0.31) but the effect of concentration in SBS has been significant (P < 0.001). In terms of ARI, in application of 15% phosphoric acid, more than 50% of the resin remained on tooth surface. In application of 37% phosphoric acid, all the resin remained on tooth surface.
Conclusions: In using of Clearfil SE bond, containing 10-MDP, preparing enamel by 15% phosphoric acid had created strong enough SBS.
Esfandiar Akhavan Niaki; Tahereh HosseinZadeh Nik; B. Abbasian; Sedigheh SheikhZadeh
Abstract
Background and aim: G-axis which is defined by the angle between line S-N and S-G would be of great use in evaluation of the mandibular growth relative to other craniofacial structures the aim of this study was to evaluate the correlation of G-axis with vertical parameters in adult patients of different ...
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Background and aim: G-axis which is defined by the angle between line S-N and S-G would be of great use in evaluation of the mandibular growth relative to other craniofacial structures the aim of this study was to evaluate the correlation of G-axis with vertical parameters in adult patients of different malocclusions.Materials and methods: Lateral cephalograms of 90 patients with different malocclusions, were traced for evaluation of some horizontal and vertical cephalometric facial parameters. The patients were classified into three groups of 30 on the basis of clinical examination, ANB angle and wits appraisal. Pearson correlation test were conducted to compare the correlation of G axis with vertical parameters in different malocclusions.Results: Y-axis length showed significant and positive correlation with G-axis length. G-axis length and lower facial height had positive significant correlation in three categories. No significant correlation was found between G-axis length and ANB angle or wits. Conclusion: Application of the Y-axis and G-vector simultaneously seem to be more useful in cephalometric evaluation of mandibular growth pattern than emphasis on one.
Esfandiar Akhavan Niaki; Roshanak Montazeri Hedeshi
Abstract
OBJECTIVE: as regards to prevalence of mouth breathing and its complications, The panoramic view of children with mouth breathing as a routine initial accessible radiographic examination, was assessed in the present study; considering Confounding factors such as the magnification, dimensional changes, ...
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OBJECTIVE: as regards to prevalence of mouth breathing and its complications, The panoramic view of children with mouth breathing as a routine initial accessible radiographic examination, was assessed in the present study; considering Confounding factors such as the magnification, dimensional changes, type of the x-ray machine and head position during imaging. We tried to innovate new standardization of nasal cavity analysis in panoramic radiography, in addition to creating specified and reliable new parameters, and investigate if there are significant differences between these parameters in mouth breathing patients than in those with nasal breathing. METHODS: This wasa control and analytical study which assessed 30 patients with Mouth breathing and 30 patients with nasal breathing, in the range of 9-12 years old with equal numbers of both sexes, in both groups. After tracing panoramic radiographs, five angular and proportional variables was created and measured, T-test was performed and the level of significance was evaluated. For investigation of nasal septum deviation, we used Chi-square test.RESULT: "NL" and "NL/B" parameters and unclear irregular view ofnasal cavity ininternal structures, showed significant differences in mouth breathing group (P.Value < 0.5). Right and left nasal cavity width in each patient, separately in two groups- mouth breathing and normal breathing- showed no significant differences. CONCLUSION: Due to availability and benefits of panoramic radiography,the proportional and angular parameters used, were reliable for assessment of nasal cavity in mouth breathing children and could be developed in future studies for diagnosis of mouth breathing children.
Esfandiar Akhavan Niaki; Javad Chalipa; Davoud Abdollahi; Mohammad Moslem Imani
Abstract
Aim: previous designs like intrusion arch (Burstone) and Utility arch (Ricketts) to intrude anterior teeth in patients with deep bite had some advantageous, which required new consideration. The present study investigated new designs in making intrusion arch.Materials and Methods: PATRAN and NASTRAN ...
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Aim: previous designs like intrusion arch (Burstone) and Utility arch (Ricketts) to intrude anterior teeth in patients with deep bite had some advantageous, which required new consideration. The present study investigated new designs in making intrusion arch.Materials and Methods: PATRAN and NASTRAN programs were used in this computerized simulation study. Burstone, Utility arch designs; proposed methods i.e. A and B were loaded in 11 different cross sections and in 3 situations.
Result: the results indicated a lower load-deflection rate in newly designed intrusion arches and a more appropriate condition for implementation of a light continues forces .otherwise, the extent and the type of this placement in posterior blocks due to intrusion arch reaction, were in better condition in new designs comparing with those impervious ones.
Conclusion: Considering the advantages of the proposed designs it seems that their implementation would lead to better results in incisor teeth intrusion.