Effect of Mobile Phone with and without Earphones Usage on Nickel Ion Release from Fixed Orthodontic Appliance.

INTRODUCTION: This study is an attempt to assess whether the usage of headphones could minimize the nickel ion release from fixed orthodontic appliance compared with hand-held mobile phones. The aim of the study is to validate the hypothesis whether there is a significant variation in nickel ion release from fixed orthodontic appliance among the patients using hand-held mobile phones and patients using mobile earphones. MATERIALS AND METHODS: This is a cross-sectional study where a total of 60 healthy individuals who were undergoing fixed orthodontic treatment in the Department of Orthodontics and Dentofacial Orthopedics, Adhiparasakthi Dental College and Hospital, Melmaruvathur, Chennai, India, and all these individuals were bonded and banded. All of them are class I malocclusion with bimaxillary protrusion. Salivary samples were collected in their regular checkup after two months and 7th, 14th, and 21st days salivary nickel level was evaluated based on their usage of mobile phones with earphones and without earphones. RESULTS: In this study, paired and independent t-tests were used. On basis of statistics results, the mean of nickel release in both male and female participants using mobile phones without earphones were significantly higher than the participants using mobile phone with earphones. CONCLUSION: By our study, we concluded that usage of mobile phones with earphones has a significant reduced effect on metal ion release from fixed orthodontic appliance when compared to usage of mobile phones without earphones.

Comparative evaluation of variations in torque expression in maxillary incisor and canine using different bracket prescriptions placed at different crown levels by finite element (FE) method: An in-vitro analysis.

OBJECTIVE: While using preadjusted brackets, the position of the bracket on the crown is one of the deciding factors that determine the tooth's final tip, torque, height, and rotation. The final tooth position is not optimal if the bracket is placed incorrectly or if the varying crown morphology does not correspond with the bracket design. The present study was conducted to evaluate and compare the variations in torque expression in maxillary incisor and canine using different bracket prescriptions placed at different crown levels by finite element method. METHODS: For the present study, three-dimensional models of maxillary right central incisor and canine were made using CREO version 4.0 software. CREO is a powerful three-dimensional (3-D) computer-based, computer-aided design (CAD) software developed by Parametric Technology Corporation (PTC) to aid in design processes. Simulation was done to replicate the clinical situation of an active palatal root torque acting on the incisor and canine. The induced palatal movement of root tips and labial movement of crowns tips, overall stress, and von Mises stress generated in the brackets and the total equivalent strains developed in the periodontal ligament (PDL) were calculated, while the values obtained were tabulated and subjected to statistical analysis. RESULTS: Based on the findings of the present study, the average maximum stress produced in the bracket was calculated as 265.069 Mpa in incisor and 166.742 Mpa in the canine. Likewise, the average of the maximum displacement of root apex observed in the present study was calculated as 0.01401 mm in the incisor and 0.00421 mm in the canine, while the average strain developed in the PDL was calculated as 0.0587 for incisor and 0.0498 for the canine. Furthermore, it was, also, observed that the magnitude of strain developed in the PDL increased with increase in the stress produced by the bracket prescription for both incisor and canine. CONCLUSIONS: Within the limitations of the present study, it was concluded that the magnitude of displacement of root apex was significantly influenced by bracket prescription and bracket position. Also, the stress developed in the bracket was influenced by bracket prescription and position, while the variation in crown morphology in the incisor and canine played a significant role in the eventual strain developed in the PDL after torque application.

Evaluation of Change in Surface Enamel Microhardness in Patients Undergoing Fixed Orthodontic Appliance Therapy - A Randomized Control Trial.

AIM: This study aims at determining the amount of enamel decalcification in terms of microhardness. MATERIALS AND METHODS: Twenty patients requiring treatment by extraction method for Class I malocclusion with bimaxillary protrusion were selected for the study. Twenty patients were randomly divided into control group and experimental group. In the control group (n = 40), extraction of permanent first premolars was done on day 1 of bonding to assess the Vickers hardness number (VHN) of enamel surface, and in the experimental group (n = 40), extraction of the contralateral premolars was done on the 28th day after bonding to assess the VHN of enamel surface. The values are tabulated and analyzed by SPSS software. RESULTS: There is significant surface enamel dissolution of enamel crystals in the experimental group compared to the control group, and a statistically significant difference in VHN is evident between the control and experimental groups. The surface enamel dissolution (VHN) is not significant difference noted between mandibular and maxillary premolars of the control and experimental groups. CONCLUSION: The present study has demonstrated a higher level of surface enamel dissolution in the experimental group. There is a marked difference in the VHN between the control and experimental groups, which is statistically significant. The scanning electron microscopy study also confirms the presence of surface enamel demineralization following orthodontic bonding.