Study Of Dentofacial Characteristics Associated With Mandibular Growth In Adult With Mandibular Anteriors Crowding

Mandibular incisors crowing is a common malocclusion. Through a large number of clinical observation,we found that the mentolabial sulcus of these patients were deeper than the normal.The suspect showding up - Will the anterior mandibular crowding result in department of alveolar anterior segment deficiency, and then the need for interceptive orthodontics to prevent the effects on the mandibular. We preliminary studied the characteristic pattern of the Classâ… malocclusion in adult with anterior mandibular crowding. Designed to demonstrate the relationship between the mandibular anterior crowding and the mandibular growth and development, and resulting in the growth and development after the end of the mandibular anterior segment deficiency,and chin-specific symptoms such as mentolabial sulcus deepen. To explore whether early t intervention on this malocclusion is necessary to promote the development of the mandible and prevent the adverse impact of facial beauty.The whole paper was divided into three parts:1.Morphological characteristics of the mandibular arch The aim of this study was to investigate the effect of mandibular incisor crowding on arch form and mandible development. To compare the study models of 114 untreated adult subjects with varying degrees of incisor crowding and 137 mandibular models of normal occlusions. The results showed that parameters of mandibular arch length were decreased significantly in the subjects except for female arch length (Lb).And the width were narrower than the normal. LII were negative correlated with IFPW in men,and ICW and IMW in women.Therefor,incisor crowding may contribute to decreasing dental arch length and narrowing dental arch width, which illustrated that we should take some intervention early to prevent the deficiency of dental arch length and width in the end of mandibular growth and development.2.Mandibular and soft tissue structure characteristic.Recording the changes in the structure of mandible and chin soft tissue by cephalograms analysis. To compare the lateral cephalograms of 100 untreated adult subjects with lower incisor crowding and 100 normal occlusions.The results are anterior mandibular alveolar bone deficiency, smaller mandibular body length, obtuse mandibular angle, retrusion of the supramental(B),and clockwise rotation of the mandibular development direction. Soft tissue for men exectly reveal the true mandibular combination and chin shape, inversely,female showed abnormal bone and soft tissue compensation.3.Anterior mandibular and chin soft tissue profile feature extraction.We detected the edge profile of hard and soft tissue by digital image processing software MATLAB 7.5.0(R2007b),then visually compared the profile of the patient group with control group. Both profile measurements of hard and soft tissues were made. Comparison of the depth of edges profile between subjects and control groups for female soft-tissue showed that no significant difference,although it was smaller in case groups.In contrast,there was significant increased in case groups for men ,regardless of the hard tissue or whether the soft tissus,and the same as the result of female hard tissue.The results indicated that more obvious degree of concavity in men mentolabial sulcus. However, lip and chin muscle of women as compensation caused by the depression of bone tissue is not obvious.