The Role Of Positioning Guides In The Implantation Of Micro-implants

Objective:Micro-implants have been routinely used for orthodontic treatment,such as lack of understanding of the implanted area before surgery,which can cause damage to surrounding tissues.This study used an individualized localization guide to help select the optimal site for micro-implant implantation and to avoid micro-implant damage to adjacent anatomical structures.To explore the influence of the positioning guide on the accuracy of the implantation site,in order to provide a reference for the clinical selection of micro-implant implantation sites.Materials and methods: Before the experiment,the individualized positioning guide and the patient's CBCT image data were used as reference.Randomly selected 15 patients who underwent micro-implant implantation in our hospital from November 2016 to August 2018 due to orthodontic treatment plan.There were 5 males and 10 females,aged 19-33 years.The inclusion criteria were: permanent dentition,the jaw anatomy was basically normal;no metal allergy or rejection history;orthodontic treatment,and fixed appliance;no serious periodontal disease;no systemic disease.The study was divided into two groups.The clinician randomly selected one side of each patient as the experimental group and the other side as the control group.CBCT was taken before micro-implant implantation.In the experimental group,the micro-implant was placed at the implant site determined by combining CBCT image data with positioning guides.In the control group,the micro-implant was placed at the implant site determined only by CBCT image data.In order to avoid the patient receiving a high radiation dose on the same day,the patient was again subjected to a CBCT scan after one month of implantation.In the InVivo5 software,the operator intercepts the scanned micro-implant,then utilize Geometer's Sketchpad V5.0,6.0 software to measure the average distance and angle deviation between the actual implant site and the ideal implant site in the intercepted image,and to evaluate the safety of Micro-implant after implantation.In the vertical direction,Micro-implant should be placed on the attached gingiva as far as possible;in the horizontal direction,the Micro-implant should be placed at the center of the root gap between two teeth as far as possible.The determination of actual implant path: after the implantation of micro-implant,the point of nail crown and nail tip are connected into a straight line,the line is considered as the actual implant path of Micro-implant.The implantation of Micro-implant for all patients were operated by the same surgeon independently,after 6 months of Clinical use,the stability of the planted Micro-implant was observed,and the dropping rate of the planted Micro-implant was recorded,all the measurement results were collect to the SPSS21.0 software for further analysis,then the differences between the results from two groups were identified,and the relevant role of positioning guides for the process of micro-implant implantation was discussed.Results:1 The average distance deviation between the actual implant site and the ideal implant site of Micro-implant's crown for the experimental group and control group were 0.88 ±0.60 mm and 1.52 ±0.45 mm respectively,the results showed that P < 0.05,the difference was statistically significant;The average distance deviation of Microimplant's tip for the experimental group and control group were 0.54 ±0.48 mm and 0.87 ±0.74 mm respectively,the results showed that P > 0.05,the difference was not statistically significant;The average angle deviation for the experimental group and control group were 5.28±1.99 degree and 8.46 ±2.05 degree respectively,the results showed that P < 0.05,the difference was statistically significant.2.After implantation,CBCT revealed that: For the experimental group,80% of the micro-implants were located between the roots of the two teeth,and approximate equidistance to the roots of both sides.The micro-implants had good retention without fall off.For the control group,33% of the micro-implants were located between the roots of the two teeth,47% of the micro-implants were skewed,and 33%micro-implants were fall off.Conclusions:The combination of individualized positioning guide and CBCT image data is able to improve the accuracy of the implanting site as well as the safety and stability of micro-implants after the implantation.