The Clinical Research Of Distalization Of Molars By Micro-implant Anchorage

Objective:To study the distalization to the molars by micro-implant anchorage,increaseingthe length of upper or lower arch by non-extraction treatmentMethod:(1) Maxillary molar distalization:Among 32 cases,10 Angle classⅡ, subdivision malocclusion patients withⅠ～Ⅱ°crowding (6 females and 4 males) were selected as the subjects aged from 11 to 13 years old (12.2 on average), All the patients were treated with non-extraction treatment by distalizing the unilateral maxillary molar with micro-implant anchorage. The micro-implant were embedded in buccal alveolar bone between maxillary second premolar and maxillary first molar(8 cases),or between maxillary first premolar and maxillary second premolar(2 cases), then the Ni-Ti coil spring were set between maxillary second premolar and maxillary first molar or between maxillary first premolar and maxillary second premolar. This study had measured the change in velocity, distance and position of the maxillary first molar, which evaluated molar movement from character to testing anchorage intensity. Casting Model analysis were used, All results were analyzed by statistics. (2) Distalization of mandibular molars:The micro-implant were embedded in buccal alveolar bone between low second premolar and low r first molar(4cases),or between mandibular first premolar and mandibular second premolar(2 cases),or between mandibular first molar and mandibular second molar(2cases)and the remote position of mandibular second molar, then the Ni-Ti coil spring were set between mandibular second premolar and first molar or between mandibular first premolar and second premolar, or between mandibular first molar and mandibular second molar, or using drag-spring to drag mandibular molar derectly.Results:(1) The maxillary first molars were bodily distalized by 3.55±0.57mm on the testing side with(1.07±0.12)mm/M. The duration of distalization of maxillary molars were from 2 to 5 months (about 3.4 months on average). The horizonal circumvolving angles and buccal movement of the first molars were of stastistic significance. (2) The mandibular first molars were bodily distalized by 3.1mm (2.2-3.6)on the testing side. The duration of distalization of mandibular molars were from 2 to 5 months (about 3.4 months on average).Conlusions:(1) The method of the distalization to the maxillary molars by micro-implant anchorage, increaseing the length of upper arch by non-extraction treatment is effective and reliable.(2) The method of the distalization to the mandibular molars by micro-implant anchorage, increaseing the length of upper arch by non-extraction treatment is also effective and reliable. It shoud be cautious to apply the micro-implant anchorage to distalize the molars because of its side effects...