Clinical Application Of Unilateral Distalization Of Maxillary Molars With Miniscrew Implants Anchorage In Class â…¡ Malocclusion

Objective: To evaluate the use of miniscrew as strong anchorage in unilateraldistalization of maxillary molars.Methods: A30year old female with Class II subdivision malocclusion patient wasselected as the subject. Jaw normal, the right maxillary canine lip to the dislocation，theright maxillary lateral incisor crossbite and palate to the dislocation, the right side molarClass II relationship, left canine and molar neutral relationship. Maxillary archcrowding of6.5mm and mandibular crowding of3.5mm. The patient had a normaloverjet and overbite, and her maxillary dental midline deviated2.5-3mm to the right,and the mandibular dental midline deviated1-1.5mm to the right relative to the facialmidline. The patient was treated by unilateral buccal side of the zygomatic crest throughimplanting miniscrew anchorage distalization of maxillary molars, with a magnitude of2.45-2.94N. This study had measured pre-and-post-treatment changes in threedimensions of the maxillary first molar, first premolar and the incisors through castmodels and cephalometric analysis, and all results were analyzed comparatively.Results: The course of orthodontical treatment lasted17months. The miniscrewimplant anchorage molar to the distal, non-extraction correction of aligned upper andlower dentition, correcting the midline and right side of the molar Class II relationship,maintaining a good facial profile, and the patient is satisfactory with the results.(1) theright maxillary first molar was bodily distalized by2.23mm, with mesioclination2°.(2)The patient being an adult，there is not significant changes for the jaw relations of theindicators after correcting, and the main changes existed in mesial movement,inclination of the upper anterior teeth, the upper and lower anterior teeth lip inclinationslightly increased than before, the corresponding upper and lower lip protrusion increasing, so that after treatment of facial profile showing more coordinated.(3) Theright maxillary molars intrusion by2.04mm, mandibular plane angle decreased by1°,vertical control appearing better, vertical height of the patient remaining constant,clockwise rotation of the maxillary and mandibular teeth not appearing.Conclusions: The patient achieved Class I molar relationship and a normal overjetand overbite. It is an effective method as strong anchorage for unilateral distalizedmaxillary molars without patient compliance and with no undesirable side effects.