ABSTRACT
Objective:To evaluate the clinical effect of distalizing mandibular dentition with micro-implant in patients with skeletal classⅢmalocclusion.Methods: In the study, 20 patients with skeletal class Ⅲmalocclusion were selected.They are consist of 8 males and 12 female with an age range from 16 to 38 years old and an average age of (21.5±5.6) years.They were treated with straight wire technique and the implant were inserted into the mandibular external oblique line to distlize the lower dentition to a class Ⅰmolar relationships.Cephalometrics films were taken before and after treatment.The changes of hard tissue and soft tissue were analyzed by evaluating 26 measurement measurements.Results: ClassⅠmolar relationships were achieved, and the profile were improved after treatment.ANB increased by(0.80±1.02)°,Wits increased by (1.67±1.74) mm,after treatment(P<0.05).The lower dentition were significantly retracted after treatment with L1-NB distance decreased by(2.64±1.50) mm, P<0.05;the mesial buccal cusp and mesial root of the lower first molars were retracted by (3.26±1.95) mm and (0.79±1.27) mm respectively (P<0.05);the mesial buccal cusp of the lower second molars were retracted by (3.06±1.80) mm (P<0.05).After treatment, mandibular teeth got up-righted distally.From incisors to molar, L1/MP, L5/MP, L6/MP, L7/MP angle decreased by(6.37±8.53)°, (10.59±8.50)°, (11.48±7.22)°, (15.72±7.16)°on average respectively (P<0.05), all of those changes had the statically significant effects.Soft tissue change after treatment, the distance from lower lip to esthetic plane were decreased by (1.70±1.59) mm on average (P<0.05).Conclusion: Distalizing mandibular dentition with micro-implant can get an satisfying result in patients with skeletal class Ⅲmalocclusion, the lower teeth were retracted by controlled tipping movement.