Cases Analysis Of Skeletal Class Ⅰ、Ⅱ、Ⅲ Malocclusion

This paper contains three cases of skeletal class Ⅰ 、 Ⅱ 、 Ⅲ malocclusion.According to the relative positions of the maxillary and mandible,the angle of the ANB measured by Cephalometric radiography,it was divided into three types from the sagittal direction.1.skeletal classⅠ: 0 ° ≤ ANB ≤5 °,relative positions of the maxillary and mandible is normal.2.skeletal classⅡ:ANB >5°,maxillary protrusion or mandible retrusion or both of above.3.skeletal class Ⅲ :ANB <0°,mandible protrusion or maxillary retrusion or both of above[1].First case is skeletal class Ⅰ,angle class Ⅲ.Chief complaint is uneven dentition.(?) crossbite,space crowded:the upper arch is 5 mm,the lower arch is 2 mm.With no-extraction to level and align dentition by flaring and elongatiing 12、22,retracting 11 、 21,interproximal enamel stipping by invisible aligner.Finally,anterior rigion crossbite is solved and normal overbite,overjet are established.Second case is skeletal class Ⅱ,angle class Ⅱ.Chief complaint is uneven dentition.Space crowded:the upper arch is15 mm,the lower arch is 6 mm.Leveling and aligning dentition,adjusting the cuspids and molars relationship to aneutral relationship,resolving the maxillary and mandibular dentition crowding are achieved by extracting bilateral the maxillary first premolar and the mandibular second premolar.Third case is skeletal classⅢ,angle class Ⅲ.Underbite and uneven dentition is his chief complaint.Mandibular protrusion,(?) crossbite,Space crowded:the upper arch is12 mm,the lower arch is 6 mm.By non-extraction treatment,a Damon 3MX appliance is used in combination with early short-distance type III elastic traction,assistant expansion arch and expansion of the arch wire are used to flare upper front teeth,establish normal overbite,overjet,occlusion relationship and improves mandibular protrusion.The subject of the summary is the orthodontic tooth movement associated with maxillary sinus floor.Maxillary posterior teet is connected tightly with maxillary sinus floor.Except Orthodontics,in the endodontics,Oral and Maxillofacial Surgery and Implantology,maxillary sinus also plays an important role.This article summarizes the anatomy,the relationship between maxillary sinus and maxillary posterior teeth,related imaging examination,effect of maxillary sinus on horizontal and vertical movement of orthodontic teeth.