Study of relation between Changes in lip Dimensions and anterior- posterior postion with alteration of anteroposterior position of anterior teeth in complete

Abstract

Introduction: the form of lips is influenced by different factors like their internal structure and their support. Weak lip support (with inappropriate support) reduces lip vermillion height compared to the time when the lip is supported by natural tissues. This study evaluated the dimensional changes of lips with anterior-posterior displacement of posterior teeth. Photographs were analyzed with descriptive statistics. Materials and methods: seven toothless patient with less than 40 years old who demanded prosthesis were selected among patients visited prosthesis ward of Tabriz Dentistry Faculty. Different displacement of anterior teeth was simulated with different experimental records' block. These record blocks which consist of cold-curing resin base and occlusion rim divided into two moveable anterior and fixed posterior parts. The posterior part of occlusion rim fixed the maxillomandibular part and the anterior part divided into four parts. After regulating rims in each state, photography was done with frontal and lateral view by Vocel NKE xa Japan camera while the Frankfort plan was parallel to floor in NHP position with blue background. The required variables were measured by a prosthesis expert, an orthodontic expert and a student. The obtained data were analyzed by using SPSS20 software and photographs were described. Results: results showed that in different positions, anterior teeth in frontal view of oral fissure curvature, the height of vermillion in upper and lower lips in low lip support (R+4.5) were significantly higher than other lip supports. There is also no significant difference in different positions of anterior teeth in lateral views of Nasolabial, Mento-lebial and z-angles was similar. But there is a significant difference between Lst-E and lit-E in different positions of anterior teeth in lateral view. Photographs showed that patients with lip support (+1.5) achieved more younger and fresh face. Conclusion: different positions of anterior teeth influence the dimensions of lips and patients with lip support (+1.5) have younger faces.