Assessment of Orthodontically Induced Apical Root Resorption during Anterior Retraction: A Computed Tomographic Study

Abstract

Introduction: External Apical Root Resorption (EARR) is characterized by loss of the superficial layer of cells that protect the tooth root. Although many studies have estimated EARR, very few studies have examined permanent teeth from central incisor to first molar with adequate radiographic techniques like Computed Tomographs (CT) as used in the present study. Aim: To investigate the prevalence and degree of orthodontically induced EARR with fixed appliances from central incisor to first molar in permanent teeth after en-masse retraction using Dentascan. Materials and Methods: All patients had Class I malocclusion with dentoalveolar protrusion and minimum crowding (<3 mm). Total 10 patients of either sex with a mean age 18.4±3.13 years were included in the study. After first premolar extraction, enmasse retraction was carried out arch using T-Loop in maxillary and NiTi closed coil spring in the mandibular arch. Root resorption in maxillary and mandibular arch was evaluated and comparison was drawn between both the arches from central incisor to first molar using Dentascan. The t–test was used for statistical analysis. Results: The results indicated that EARR occurred in almost all the teeth from incisors to first molar but the maxillary arch was more affected compared to the mandibular arch. Lateral incisors in both the arches showed maximum root resorption (maxillary arch-1.79±0.71 mm, mandibular arch-1.51±0.85 mm) followed by central incisors (maxillary arch-1.57±0.88 mm, mandibular arch-1.49±0.85 mm) and molars (maxillary- mesiobuccal root0.49±0.49 mm, distobuccal root- 0.81±0.53 mm, palatal root1.25±0.96 mm, mandibular- mesial root- 0.42±0.25 mm, distal root- 0.42±0.20 mm) whereas minimum root resorption was seen in premolars in both the arches (maxillary arch-0.49±0.32 mm, mandibular arch-0.38±0.20 mm). Conclusion: Root resorption was seen in all the teeth to some extent. Lateral incisors showed more resorption compared to central incisor whereas premolars showed least resorption in both the arches.

Keywords

• external apical root resorption
• en-masse retraction
• dentascan