بررسي تاثير درمان ارتودنسي ثابت بر تحليل اپيكال ريشه دندان هاي ثناياي فك بالا

Effect of fixed orthodontic treatment on apical root resorption of upper maxillary incisors

Background & Aim: External apical root resorption is an undesirable consequence of orthodontic treatment, which could occasionally compromise the benefits of an otherwise successful orthodontic outcome. There is no agreement about incidence of resorption after orthodontic treatment and no valid data is available in Iran. Thus, to determine the effect of fixed orthodontic treatment on external apical root resorption, this study was performed. Method & Materials: This clinical trial was performed on 40 fixed orthodontic patients (17 males and 23 females) aged between 12 and 22 years old. Standard radiographs using long cone paralleling technique were obtained before and also six and twelve months after treatment initiation. Quantitative measurements of the crown and root length for each maxillary incisor were taken and corrected for image distortion using computer and software programs. Root length reduction was calculated and resorption amounts of more than 1.2mm per year was considered as "clinically significant". Results: Root resorption rates for maxillary central incisors were 0.78±0.40mm (4.6% of initial root length) and 1.68±0.70mm (9.9% of initial root length) six and twelve months after orthodontic treatment initiation (p<0.001). For maxillary lateral incisors resorption amounts were 0.87± 0.51mm (5.5% of initial root length) and 1.83* 0.73mm (11.6% of initial root length) six and twelve months after orthodontic treatment initiation, (p<0.001). Clinically significant resorption was found in 73.7% of central and 81.7% of lateral incisors (p<0.001). No relation between apical root resorption and gender, tooth type, treatment technique and treatment phase was observed. But statistically significant effect of premolar extraction (p<0.07) and treatment duration (p<0.001) was shown. Conclusion: The results showed relatively high rate of apical root resorption up to twelve months after fixed orthodontic treatment. Accurate supervision of rootsʹ condition and length during the treatment especially in susceptible patients and also improvements in orthodontic techniques and materials seems inevitable.