Soft Tissue Profile Changes Following Incisor Retraction at the Aage Range of 15 to 24 Years

The purpose of this study was to investigate the soft tissue profile changes of the lower face following premolars extraction and incisor retraction. In order to do that, pre-and post treatment lateral cephalometric radiographs of 40 female orthodontic patients, with cl. II div. I malocclusion (22 patients) and bialveolar protrusion (11 patients) were analyzed. At beginning of orthodontic treatment, their mean age was 18.10 years, ranging from 15-24. All cephalometric radiographs were analyzed by a conventional and confirmed method called "combination analysis". The findings revealed that "lip tension" is a significant factor in soft tissue response to orthodontic treatment, so that in patients with lip strain, nasolabial angle increase was significantly more that those without lip strain. Moreover, regarding the increase of vermilion thickness of the upper lip, a significant difference was observed between two groups. In patients with lip strain, following premolars extraction and incisors retraction, lip strain was reduced or eliminated and upper lip vermilion thickness increased, following incisors retraction, the slope of nasal inferior border, in the group with lip strain, was reduced, while in the group without lip strain, this slope increased

Changes of hyoid bone position following treatment of class II div1 malocclusion with Farmand functional appliance

Background and Aim: Unlike other bones of the head and neck, hyoid bone has no bony articulations. It is connected to mandible, cranium and pharynx through muscles and ligaments. During treatment with functional appliance in patients with class II div1 malocclusion, mandible is positioned in inferior and anterior direction. Regarding the relation between hyoid and mandibular bone, alterations of hyoid bone position can be a result of functional appliance therapy. The aim of this study was to evaluate the changes of hyoid bone position following treatment with Farmand functional appliance in patients with class II div 1 malocclusion. Materials and Methods: In this before-after clinical trial, 28 patients with class II div 1 malocclusion which were under treatment with Farmand functional appliance for 11 months were selected. Facial growth in vertical, normal or horizontal direction was determined by cephalometric measurement. Data were analyzed with Paired-t test to compare the differences of mean values pre and post treatment. Variance analysis was used to compare the three growth patterns. P<0.05 was considered as the limit of significance. Results: Hyoid bone shifted significantly forward in horizontal dimension (P<0.01) and non-significantly upward in vertical dimension. There was no significant difference among the three studied groups with respect to hyoid bone position alterations in horizontal dimension but significant difference was observed between horizontal and vertical growth pattern in vertical dimension (P<0.05). There was significant correlation between decrease of ANB angle and forward movement of hyoid bone. Conclusion: Based on the results of this study, treatment with Farmand functional appliance (Fa II) leads to significant alterations in the position and anterior displacement of the hyoid bone

Evaluation of dentoskeletal effects of Farmand functional appliance (Fa II) on class II malocclusion

Background and Aim: Functional appliances refer to a variety of removable or fixed appliances designed to alter the mandibular position both sagitally and vertically, resulting in orthodontic and orthopedic changes. Despite the long history of functional appliances, there is still much controversy related to their effectiveness and mode of action. The aim of this study was to evaluate dental and skeletal effects of Fa II in patients with class II malocclusion due to mandibular deficiency.Materials and Methods: In this before-after clinical trial, 35 patients with class II div I malocclusion were selected. These samples were under treatment with Fa II appliance for 11 months. The range of age of females was 10-13 years and males 11-14 years. Combination analysis was used to determine skeletal and dental effects. Paired t-test was used to compare the differences of mean value pre and post treatment. P<0.05 was considered as the level of significance. Results: There was significant difference between pre and post treatment in respect to posterior and anterior facial height, eruption of upper and lower posterior teeth, eruption of upper anterior teeth, mandibular body length, ANB angle, IMPA and 1 to SN. No significant difference was observed between pre and post treatment regarding facial growth.Conclusion: Treatment with Fa II functional appliance leads to significant alterations in dental and skeletal elements of craniofacial complex and improvement of dental and jaws relationship

In vitro Evaluation of Microleakage of Orthodontic Brackets Bonded Using Methacrylate and Silorane Base Composite

Background: One of the orthodontic treatment problems, which causes marginal gaps and microleakage between tooth and composite is microleakage of composite bonding of orthodontic brackets. The microleakage formation permitting the passage of bacteria and oral fluids, which may cause white spot lesions under the brackets surface area.This is a clinical problem during orthodontic treatment. Few studies have been conducted in this area. The aim of this study was comparison of microleakage of composite silorane base and methacrylate base composite in orthodontic brackets. Methods: Thirty human premolar were collected and divided into 2 groups. In group 1, 15 orthodontic brackets were bonded using silorane base composite, in group 2, 15 orthodontic brackets were bonded using methacrylate base composite. Then the teeth were kept in water and thermo cycled(500×, 5-55°C). Specimens were further sealed with nail varnish, stained with 5% basic fuchsin for 24 hours. Then, all teeth sectioned and dye penetration rate were examined by an esteriomicroscope, and scored 0 to 3 for marginal microleakage for the bracket- adhesive and adhesive-enamel interfaces. The data collected analyzed with SPSS16 software, and fisher exact and Mann Whitney tests. Results: Microleakage values were lower in silorane composite than in the methacrylate group, and this difference was found to be statistically significant(P-value =0.03). Also, the rate of microleakage between adhesive-bracket than adhesive-enamel interface was meaningful(P-value=0.025). Conclusions: The results of the current relealed that silorane-bass silorane-base composite provided low microleakage for orthodontic brackets, for this reason, it could be used it for bonding brackets

Evaluation of the effect of early clinical exposure on professional attitude of dental students of Shahid Sadoughi University of Medical Sciences in 2011-2012

Introduction : Learning dentistry could have many tension and anxieties like encountering to a strange clinical environment. Early clinical exposure (ECE) is supposed to control these stresses. ECE program is an increasingly widespread component of educational curriculum. This study aims to determine the effect of early clinical exposure on the attitude of dental students’ towards dental education and profession. Methods: An analytic study was performed on all 72 dental students studying basic science at Faculty of Dentistry of Shahid Sadoughi University of Medical Sciences consisted of a short term course of introduction to clinical environment in academic year of 2011-2012. Every 12 students attended in an one day ECE course from 8 AM to 1 PM. Students ' attitude towards dental profession and education were assessed by a questionnaire included 25 items before and after the course .For data analysis descriptive paired-t-test was used. Results: All students completed the questionnaires. Students' attitude towards dental education and profession was evaluated. Mean score of students' attitude before and after exposure to clinical environment were 94.6 and 100.5 respectively .Significant differences were found in the students' attitude before and after the course (P=0.001) Conclusion: Based on the results of this study, we found a positive effect of early clinical exposure on attitudes of first and second year dental students. Demographic variations had an effect on the students' attitude .Therefore we suggest that early clinical exposure should be added to educational curriculum of dental students