Evaluation of Tooth Surface Characteristics after Application of Intrusive Orthodontic Forces Using Scanning Electron Microscope: An In vivo Study

Abstract

Introduction: Orthodontic forces when applied to tooth structure leads to some amount of resorption depending upon force duration and magnitude applied. Study aimed to evaluate tooth surface changes after application of intrusive orthodontic forces using scanning electron microscope. Materials and Methods: 20 patients were selected requiring first premolar extraction for treatment of malocclusion with fixed mechanotherapy and were divided into four groups. Group I and III consisted application of 50 gm of light force on right side and left side respectively for 4 weeks intervals. Group II and IV consisted application of 150 gm of heavy force on right side and left side respectively for 8 weeks intervals. A cantilever spring was attached from buccal tube of molar band to bracket bonded on first premolar. After 4 and 8 weeks respectively; first premolars were extracted and surface chareacteristics were evaluated using SEM. Each tooth sample was divided into middle and apical third and further into buccal, lingual, mesial and distal surfaces on each tooth. Results: Statistical significant (P < 0.001) changes were observed in middle third area using both light and heavy forces. Conclusions: Heavy forces during intrusion should be used cautiously in orthodontic biomechanics, if such procedures are to be carried out over a long period of time.