Correlation Analysis Of Protrusive Condyle Path Inclination With Partial Occlusal Factors In Skeletal Class Ⅰ And Class Ⅱ Malocclusion Patients & Case Report

Objective: To investigate the relationship between protrusive condyle path inclination and partial occlusal factors in skeletal Class I and Class II malocclusion patients.Methods: 50 patients with skeletal Class I malocclusion and 50 patients with skeletal Class II malocclusion were selected.The protrusive condyle path inclination and some occlusal measurements were measured and analyzed by X-ray cephalogram.Results:(1)There were significant statistical differences in protrusive condyle path inclination(CA)and mandibular plane Angle(MFA)between skeletal Class I and Class II malocclusion patients.There were significant statistical differences in Downs occlusion plane and functional occlusion plane.However,there were no statistically significant differences in Incisal path inclination(IA)and curve of Spee between the two groups of patients.(2)There was no correlation between protrusive condyle path inclination(CA)and occlusal factors in skeletal Class I malocclusion patients.(3)protrusive condyle path inclination(CA)in skeletal Class II malocclusion patients was positively correlated with functional occlusion plane,but not with other occlusal factors.Conclusion: The protrusive condyle path inclination in skeletal Class I malocclusion patients is steeper than that in skeletal Class II malocclusion patients.In these two types of malocclusion patients,the relationship between protrusive condyle path inclination and occlusal factors is inharmonious or abnormal,which may be a potential risk factor for temporomandibular joint symptoms,and should be paid attention to by doctors.At the same time,when doctors establish a new occlusal relationship through orthodontic treatment,they should pay attention to the coordination between the occlusal relationship and the condyle,which is conducive to maintaining the health of stomatognathic system.Objective: To observe and analyze the effect of clinical treatment of adult patients with skeletal Class II malocclusion,after comprehensive pretreatment examination and analysis,detailed orthodontic plan was formulated,fixed orthodontic technology was used,and different orthodontic strategies were adopted,including different extraction position,anchorage control technology and orthodontic process.Materials and Methods: We select three adult patients with skeletal Class II malocclusion treated by me during my postgraduate study.Case 1: DHP,an 18-year-old girl.Her chief complaint was "poor occlusion of right posterior teeth",accompanied by temporomandibular disorder(TMD);skeletal Class II malocclusion with average mandibular plane angel,maxillary protrusion,and mandibular retrusion with mandibular hypoplasia;severe crowding of upper and lower dentition,bilateral Class II relationship of canine teeth and molars,a deep overbite and overjet of anterior teeth,the right second premolar and molar are scissors bite.In the upper jaw,the transpalatal arch(TPA)was used to control the position of the maxillary molars,and the bite was opened with the splint.The right posterior scissors bite was first released by interactive traction.Then,teeth of No.14,24,35,and 45 were extracted to level and align the upper and lower dentition,and retract anterior teeth to reduce protrusion and improve occlusal relationship.Case 2: LBH,a 27-year-old girl.Her chief complaint was "irregular teeth",skeletal Class II malocclusion with average mandibular plane angel;the upper and lower lips protrude seriously,mandibular hypoplasia,and mandibular retrusion.The upper teeth are crowded moderately,and the lower teeth are crowded severely,with Class I relationship of molars,a deep overjet,abnormal Bolton index.Three first premolars and one second premolar with caries were extracted.In the upper jaw,micro-screws were used for strong anchoring to retract anterior teeth,and at the same time,the vertical height was controlled to prevent the deterioration of the face shape.In the lower jaw,the extraction space of teeth was used to level and align the dentition,and the anterior teeth were retracted as far as possible to reduce the protrusion.Case 3: LYT,a 21-year-old girl.Her chief complaint was " bucktooth",skeletal Class II malocclusion with high mandibular plane angel;the upper and lower lips protrude seriously,maxillary protrusion,and mandibular hypoplasia with severe chin retraction;the upper and lower teeth are slightly crowded,open bite and a deep overjet of anterior teeth,bilateral Class II relationship of canine teeth and bilateral Class I relationship of molars.The four first premolars were extracted for camouflaged orthodontic treatment,the PASS was used for anchorage control,the extraction space of teeth was used to retract the anterior teeth,the upper and lower anterior teeth were retracted as far as possible to reduce the protrusion,improve the profile,and establish a normal occlusal relationship.Result: The three patients were treated with different orthodontic programs and fixed orthodontic techniques,and the occlusal relationship was well established,and the soft tissue profile was significantly improved.Conclusion: For skeletal Class II malocclusion of adult patients,orthodontist need to carry out detailed examination and analysis before treatment,then conclude the correct diagnosis.Since adult patients have no potential for growth and development,the treatment plan should be formulated according to the individual situation and clinical conditions of the patients,and the appropriate fixed treatment technology can be used to obtain satisfactory treatment results for both doctors and patients.