Comparison of apical root resorption in patients with maxillary anterior intrusion using two and single micro implant placement

Introduction: Orthodontic treatment with mini implant skeletal anchorage system has become increasingly popular in the recent times and very few literature compare effects of different types of incisor intrusion mechanics and apical resorption associated with it. In this study we compare apical root resorption in orthodontic patients with maxillary anterior intrusion using one mini implant and two mini implant placement in patients with gingival smile.
Aim: To compare the amount of root resorption during anterior intrusion using one implant and two implants in patients with gingival smile
Objectives:
• To evaluate the amount of root resorption during anterior intrusion using single mini implant.
• To evaluate the amount of root resorption during anterior intrusion using two mini implants.
• To compare the amount of root resorption during anterior intrusion using single implant and two implants.
Method
• The sample size included 14 patients which were further divide into two Groups . The Group A consist of 7 patients and Group B consist of 7 patients.
• For both Group A and Group B conventional orthodontic mechanics were employed using 3M UNITEK MBT 0.022inch slot brackets .
• For both the Groups initial levelling and aligning was performed by using 0.016 inch NiTi arch wire followed with 17 x 25 NiTi and 19 x 25 NiTi and then to 19 x 25 stainless steel wire.
• 0.019 x 0.025-inch stainless steel arch wire was placed for intrusion of upper anteriors with the help of mini implants by placing single implant in Group A below the anterior nasal spine and in Group B mini implants were placed bilaterally between lateral incisor and canine.
• Before placement of mini implants pre-treatment study models, photographs and RVG (T0) were taken. RVG was taken using the paralleling technique for standardization of the angulation, paralleling technique is accomplished by placing the receptor parallel to the long axis of the tooth .
• In Group A mini implant was place on the Anterior nasal spine (ANS) and were attached from the mini implant to the arch wire with the help of E-chain with 90 gms force and was checked using the Correx tension gauge.
• In Group B mini implants were placed between distal to lateral incisors, ie, between upper lateral incisors an canine on both side of the dentition and are attached to the arch wire with the help of E-chain, similarly the forces given is checked using Correx tension gauge.
• After 6 months of intrusion post treatment (T1) study models, photographs and RVG was taken.
• The amount of root resorption was analysed by the help of VixWin Platinum – KaVo version 3.5 software by comparing the pre treatment and post treatment length of both central incisor and lateral incisor lengths from the incisal edge of the tooth to the tip of the apex. The differences were noted for evaluating amount of apical root resorption that has occurred.
Results: The results from the RVG study showed intrusion was highly significant in patients with deep bite and gingival smile. Linear measurements used for the study were subjected to statistical analysis using the Wilcoxon signed rank test to check the treatment changes. Initial and the post treatment root resorption was calculated with the help of RVG and the results showed intra Group values were statistically significant and inter Group results were non-significant.
Conclusion: The present study showed root resorption is over 1 mm, being positively related to the amount of intrusion with no significant differences between cases treated with one or two mini implants ; it ceases at the end of active treatment. Stability is satisfactory when using either one or two mini screws.