Alok Ranjan; Anil Kumar Biradar; Ankita Patel; Vanessa Varghese; Ankita Pawar; Rohit Kulshrestha
Abstract
Objectives: This studied aimed to measure the yield strength and stress relaxation properties of three commercially available thermoplastic aligner materials.
Methods: The three different thermoplastics aligner materials Duran (Scheu, Iserlohn, Germany), Erkodur (Pfalzgrafenweiler, Erkodent, Germany) ...
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Objectives: This studied aimed to measure the yield strength and stress relaxation properties of three commercially available thermoplastic aligner materials.
Methods: The three different thermoplastics aligner materials Duran (Scheu, Iserlohn, Germany), Erkodur (Pfalzgrafenweiler, Erkodent, Germany) and Track (Forestadent, Germany) were selected. A three-point bending test was carried out via the universal testing machine to measure their yield strength and stress relaxation properties. An independent t-test was performed for intergroup comparison. P-value < 0.05 was set as the level of significance. Results: All the selected three polymers liberate a notable amount of stress during 24 hours. The highest stress release was observed in Duran i.e. 18.96 N/cm2 as compared to Erkodur, which was 13.96 N/cm2 and Track, which was 13.18 N/cm2. The yield strength of Duran was the highest (75.85 Mpa) compared to Track and Erkodur with the yield strength of 52.75 Mpa and 55.86 Mpa, respectively.
Conclusions: Tooth movement is influenced by the composition of aligner material and its thickness. Duran had the highest stress release and yield strength. Stress released by different aligners exceeds around half of the initial stress value, which directly affects the orthodontic force application and subsequent tooth movement.
Amrita Basak; Pavan Kumar Vibhute; Chetan Patil; Vinay Umale; Rohit Kulshrestha; Khusali Rathod
Abstract
Objectives: This study aimed to evaluate gender dimorphism in anterior malar projections using clinical photographs and lateral cephalograms.
Methods: Thirty subjects aged 18 - 25 years were taken for the study. Based on the gender they were divided into two groups group A (15 subjects) male and group ...
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Objectives: This study aimed to evaluate gender dimorphism in anterior malar projections using clinical photographs and lateral cephalograms.
Methods: Thirty subjects aged 18 - 25 years were taken for the study. Based on the gender they were divided into two groups group A (15 subjects) male and group B (15 subjects) female. On the profile photographs positive and negative vectors were labelled. Sella-nasion-orbitale (SNO) angle was delineated with the aid of NemocephTM software. The data was then statistically analysed. Results: Skeletal differences between the positive and negative vector groups on basis of SNO angles were statistically significant (P < 0.001). The angulation value obtained for SNO was smaller in the negative vector when compared to the positive vector on an average by 5.9°. No difference in values between males and females was seen.
Conclusions: The projections of anterior malar can be effectively categorized by mere visually assessing the vector relationship (by photographs). This method can be used to diagnose maxillary hypoplasia and can help plan different treatment alternatives.