Pseudo class III

DIAGNOSTIC CRITERIA FOR PSEUDO-CLASS III MALOCCLUSION: 

DIAGNOSTIC CRITERIA FOR PSEUDO-CLASS III MALOCCLUSION A.B.M.Rabie and Yan Gu

PSEUDO-CLASS III MALOCCLUSION: 

PSEUDO-CLASS III MALOCCLUSION Pseudo-Class III malocclusion has been identified with anterior crossbite as a result of mandibular displacement. Premature contact between the maxillary and mandibular incisors results in forward displacement of the mandible in pseudo- C lass III malocclusion so as to disengage the incisors and permit further closure into the position in which the posterior teeth occlude. Moyers suggested pseudoClass III malocclusion as a positional malrelationship with an acquired neuro-muscular reflex.

PowerPoint Presentation: 

The aim of this study is to identify the diagnostic criteria for pseudo-Class III malocclusion and compare it with Class I malocclusion in the southern Chinese population. Findings of this study showed that patients with a pseudo – Class III malocclusion exhibit certain morphologic, dental, and skeletal characteristics that should be of aid in the diagnosis of pseudo – Class III malocclusion.

67 Pts (mean age 10.9 ± 1.8): 

67 Pts (mean age 10.9 ± 1.8) 36 Pts Pseudo- C lass III malocclusion anterior crossbite mandibular displacement patients were treated for an avg 7months to procline upper incisors and retrocline lower incisors southern Chinese 31 Pts with Class I malocclusion skeletal Class I malocclusion with normal overjet and overbite mild to moderate crowding with Class I molar relationship straight facial profile Southern Chinese

STUDY METHODS: 

STUDY METHODS Characteristics analysed: Family history Molar relationship Canine relationship Pre-treatment lateral Cephalograms

RESULTS: 

RESULTS FAMILY HISTORY: 72% of the examined cases in the pseudo -C lass III malocclusion group showed no family history 28% reported family history

PowerPoint Presentation: 

2. MOLAR RELATIONSHIP 75% of the examined cases in the pseudoClass III malocclusion group showed Class I molar relationship at CO and Class II relationship at CR 8% showed Class III molar relationship at CO and Class I relationship at CR 11% showed Class II molar relationship both at CO and CR 6% showed Class I molar relationship at both CO and CR All of the examined cases in the Class I malocclusion group showed Class I molar relationship at CO.

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3. CANINE REALTIONSHIP 81% of the cases with either deciduous canine or permanent canines showed Class I relationship at maximum intercuspation and Class II relationship at CR All of the examined cases in the Class I malocclusiongroup showed Class I canine relationship at CO.

Ceph Analysis: 

Ceph Analysis

PowerPoint Presentation: 

Pseudo-class III Cass I Normal values SNA 81.6 82.2 75.5 - 85.5 SNB 81.1 77.4 76.0 - 82.0 ANB 0.53 4.90 *** 1 - 5 Facial axis -4.67 -7.26 *** SN/Mp 33.7 35.7 N/S MnPl angle 26.6 29.3 N/S UI/MxPl 114.5 116.1 112 - 124 LI/MnPl 96.0 91.0 90 - 104 LAFH 63.6 65.1 NLA 104.4 100.2 N/S

CONCLUSION: 

CONCLUSION Majority showed no family history. Class I molar and canine relationships at CO Class II or end to end relationship at CR. Decreased midface length. Forward position of the mandible with normal mandibular length. Retroclined upper incisors and normal lower incisors. Retrusive upper lip

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