A Clinic Study On Micro Implant And Traditional Methods For Bite-opening

[Objective] To investigate and Comparing the clinical effects of micro implant and traditional methods in the treatment of deep overbite and steep curvature of spee of the lower incisor.Estimate the changes of the mandibular incisors in the process of unlocking the bite.Evaluate the degree of root resorption on lower incisors,and the mechanism of bite-opening to provide information for the orthodontic treatment.[Methods] The study population comprised20patients with Angle class II division1malocclusion, anterior deep overbite class Ⅱ1°-Ⅲ°, curvature of spee more than2mm,tooth extracted(4premolars).All patients who underwent orthodontic treatment at the orthodontics Department of Stomatology Hospital Affiliated Kunming Medical University.The sample was randomly divided into2groups according to the methods used to bite-opening:(1)A group:micro implant group(n=10);(2)B group:flat bite plate combined with rocking-chair archwire(n=10).Both two groups were treated with heat-activated nickle-titanium wire which is produced by3M company in aligning and leveling stages.In clinical application,archwire were changed in a certain sequence:0.014-inch,0.016-inch,0.016x0.022-inch,and0.019x0.025-inch.,times for return visits were all the same-8weeks.Micro implant were inserted into the labial alveolar bone between the roots of mandibular lateral incisors and canines when0.016x0.022-inch heat-activated nickle-titanium wire was applied to lower dental arch in the A group,and then40g force in each side was imposed immediately.After the alignment of the upper dental arch,B group used flat bite plate.when0.016x0.022-inch heat-activated nickle-titanium wire was applied to lower dental arch,B group used rocking chair archwire to level the spee curve.The CBCT scans cephalometrical film and models was made in two groups after6months to measure the curvature of spee,the length of the tooth root,the tilt of lower incisors,and the height of mandible.[Results] Early stages of orthodontic treatment resistant planting nailing group (A) combined with a rocking chair and a flat-screen guides arch (group B) occurred after treatment with varying degrees of root resorption, no statistical difference between the two groups; A group after treatment of lateral root resorption greater than the lower central incisors relative:In group B after root cut slightly larger than the lateral incisor absorption treatment, both groups were cut down and absorb the difference between the lateral incisor not statistically significant. A group ANB angle decreases in the course of bite-opening average1.56±0.41°; the Incisor average2.58±0.58mm (P<0.01); molar slightly increased, on average1.06±0.55mm (P>0.05); lower front teeth lip pour a small amount on average1.39±0.52°(P>0.05). Mandibular rotation indicator reaction after treatment, no statistically significant (P>0.05). Group B open bite during the ANB angle increases, the average1.34±0.22°; molars increased, on average3.49±1.12mm (P<0.01); anterior lip down-dip, with an average4.51±0.99°(P<0.01) lower incisors the down less on average1.16±0.60mm (P<0.05). Indicators FMA reaction jaw rotation, Y-axis angle, below the high/high overall were increased after treatment, the difference was statistically significant (P<0.05). After treatment, FMA, Y-axis angle, below the high/high group B were higher than overall A group, the difference was statistically significant; A group L1-MP is reduced from an average of2.58±0.58mm, reducing the volume in group B (P<0.01); group B L6-MP increased from an average of3.49±1.12mm, increased volume in group A (P<0.01). OB values and Spee curve values in group A were reduced after treatment2.99±0.52mm,2.61±0.43mm compared with group B1.69±0.21mm,1.23±0.18mm drop much, there are significant differences (P <0.01).[Conclusion]1. Orthodontic treatment bite-opening nail group stage planting guides combined with the plane rocking bow group after treatment have occurred in central incisor with different degrees of lateral incisor root resorption.There is no significant difference between the groups.2Micro planting nail open bite down incisors achieved mainly through the lower jaw clockwise obvious for both angle or high-angle deep overbite cases; plane rocking bow guides combine bite-opening mainly through the increase of molar and the anterior teeth and lips pour down implementation jaw clockwise significantly for both low-angle or angle-deep overbite.The mechanisms is different which is use bite-opening in two groups. 3Bite-opening of orthodontic treatment efficacy is superior to flat planting nailing guides combine anti-rocking bow.