[Evaluation of the correction of the skeletal class III malocclusion by distalization of the whole mandible dentition with micro-implant anchorage].

OBJECTIVE: To evaluate the clinical effect of distalizing mandibular dentition with micro-implant in patients with skeletal class III malocclusion.

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 I molar 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: Class I molar 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 III malocclusion, the lower teeth were retracted by controlled tipping movement.