Allahyar Geramy; Tahura Etezadi; Ahmad Reza Shamshiri; Mohammad Javad Kharazifard
Abstract
Introduction: An appropriate force system is a perquisite of desirable and predictable tooth movements during orthodontic treatment. Complete knowledge about the generated forces and moments by loops is essential to choose the best one for every situation.The aim of this study was to establish a mathematical ...
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Introduction: An appropriate force system is a perquisite of desirable and predictable tooth movements during orthodontic treatment. Complete knowledge about the generated forces and moments by loops is essential to choose the best one for every situation.The aim of this study was to establish a mathematical equation to bring about a relationship between the L-loop height, width, activation and the produced force.Materials and methods: Six 3D finite element models were designed for L-loop without preactivation bends. Loops were designed with different widths (w) and heights (h). The cross section of wire was 0.016”× 0.022”. The distal end of each model was activated 1 mm in 0.1 mm intervals. The force produced by activation in a 0.1 millimeter increment was recorded. Results: Force findings were different according to the loop parameters defined. The produced force varies from 0.106 to 0.228 N for a 0.1 millimeter of activation and increased from 1.07 to 2.27 N in 1.0 mm of activation.Conclusion: The magnitude of force by L-loop can be estimated through adjustment of vertical part and activation as Increments of activation increased the delivered force while Increasing L-loop height decreased the generated force.
Allahyar Geramy; Hannane Ghadirian; Mohammad Javad Kharazifard; TajGaldi Katooki
Abstract
Aim: anterio-posterior discrepancies and differentiating the involved problems make a major part of our diagnosis and treatment. The main goal of this study was to compare the Materials and methods: In this cross sectional study, 105 pre-treatment lateral cephalograms (42 males and 63 females; 12±3 ...
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Aim: anterio-posterior discrepancies and differentiating the involved problems make a major part of our diagnosis and treatment. The main goal of this study was to compare the Materials and methods: In this cross sectional study, 105 pre-treatment lateral cephalograms (42 males and 63 females; 12±3 years old) The cephalograms were classified according to Angle classification. In all cephalograms, the ANB angel, Wits analysis, β angel, µ angel, Jaraback index and Bjork angels were measured.Results: The highest accordance between clinical observation and Wits appraisal was seen in class III group. The most accordance of the ANB angel was in the class II group.The best correlation was found between µ angel and β angel (r=0.912). The correlation of ANB angel with µ angel was the weakest (r=0.769).The results showed that when angle is smaller than 12.7 degrees, the patient is skeletal class II and the patients whose angle is larger than 19.1 degrees are classified in class III group.Conclusion: All of four sagittal parameters (ANB angle, Wits, β angle and µ angle) were well-correlated. The best correlation was found between µ angel and β angel. The correlation of ANB angel with µ angel was the weakest. angle and angle are proper tools to show skeletal class II and class III, but these angles cannot differentiate prognatic or retrognatic jaw.
