title: Smile line and occlusion: An epidemiological study.
abstract: BACKGROUND
  The purpose of the present study was to discuss some new concepts of the desirable characteristics of smile tooth display. Due to the increasing application of cosmetic dental treatments, there is an increasing need for better understanding of the esthetic principles.
  
  
  METHODS
  In the present descriptive study, with 212 participants, included were patients with no history of orthodontic treatment, loss or prosthetic replacement of anterior teeth, extracted teeth, lips with asymmetry or a history of trauma. Chi-square test was used to determine possible significances in the relation of smile line to Angle occlusion class, overbite and overjet and arch form. A P level of <0.05 was set as to be significant.
  
  
  RESULTS
  Chi-square test indicated that there was a significant difference between the smile design and overbite, overjet and gender but no statistically significant association was found between the smile design and crossbite, molar Angle classification and arch form.
  
  
  CONCLUSIONS
  Within the limitations of such studies, it might be concluded that there is a significant and important relation between some occlusal parameters and smile design, which must be considered.
authors.affiliation: Craniomaxillofacial Research Center, Azad University, Tehran, Iran.
authors.forename: Mahsa
authors.initials: M
authors.lastname: Harati
authors.affiliation: Department of Fixed Prosthodontics, Tehran Dental Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Shahbaz Naser
authors.initials: SN
authors.lastname: Mostofi
authors.affiliation: Department of Fixed Prosthodontics, Tehran Dental Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Ezzatollah
authors.initials: E
authors.lastname: Jalalian
authors.affiliation: Dental Section, Farzan Clinical Research Institute, Tehran, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Rezvani
keywords: Dental esthetics; occlusion; overbite; overjet; smile line