Accelerating Canine Retraction In Orthodontics Treatment :A Clinical Study Of A New,Minimally-invasive Corticotomy Technique

Objective: The purpose of this study was to clinically evaluate the speed of canine retraction 、 the clinical feasibility and safety under a new, minimally-invasive corticotomy technique assisting orthodontics treatment,to provide the basis for clinic treatment.Methods: The sample consisted of 3 adult patients(1 men, 2 women; mean age, 21.7 years)exhibiting Class 1 malocclusion with bimaxillary protrusion, overall health and no systemic disease,requiring to extract the first premolars and subsequent retract the bimaxillary canines in4-quadrants. Under local anesthesia completely extracting the bimaxillary first premolars, All samples used with MBT orthodontic techniques, after the initial lining and leveling, the mini-screws was implanted in the bimaxillary alveolar interval of the second premolar and the first molar. A new, minimally-invasive corticotomy technique facilitated orthodontics was randomly assigned to one side of the bimaxillary arch at the canine-premolar region, and the other side with no surgical trauma served as the control. By using miniscrews as anchorage, canine retraction was initiated via closed nickel-titanium coil springs applying 150 g of force in 4-quadrants. Anti-infection treatment in postoperation, subsequent visit in three days and a week of postoperation, observe the patients’ pain degree、swelling reaction healing recovery, and subsequent visit once every two weeks. The following variables were examined during the period of canines retraction:the distance of canines movement backwards; Shooting CBCT in preoperative and after the tooth extraction clearance closed to evaluate the root absorption; checking the pulp vitality in preoperative and after the tooth extraction clearance closed; Measuring plaque index, gingival index, sulcus bleeding index in every subsequent visit to evaluate the periodontal status.Results: 1.After 3 days of the minimally-invasive corticotomy technique,patients had s lightly pain 、swelling in the field of minimally-invasive surgery, but no effect on speech an d eating. The wound healed and returned to normal after 1 week. 2.There was no significantly di fference in the pulp vitality and periodontal condition of treatment group compared with contro l group, respectively(P>0.05). 3.The root resorption of canines existed in the experiment group and the control group, the root resorption volume was significantly decreased of experiment gr oup compared with control group(P<0.05). 4.The acceleration of tooth movement and the shor ten of treatment period significantly decreased of experiment group compared with control group(P<0.05).Conclusion:Compared with conventional treatment, the minimally-invasive corticotomy technique can effectively accelerate the tooth movement.And can reduce the risk of root a bsorption in orthodontic treatment. There was no statistically significant difference between preoperative and postoperative measurements of plaque index, gingival index, sulcus bleed ing index and pulp vitality. Little aggressiveness and more easily acceptable to patients. S o, the new、minimally-invasive corticotomy technique can be a feasible treatment modality for adults seeking orthodontics treatment with reduced treatment times.