title: [A preliminary study on the functional occlusion characters of the patients who had essential root resorption in anterior teeth].
abstract: OBJECTIVE
  In order to determine the effect of functional occlusion on the essential root resorption, we compared the characters of functional occlusion between the patients who had essential root resorption in anterior teeth and who didn't have.
  
  
  METHODS
  Panoramic radiography, periapical films and clinical data were used to diagnose the essential root resorption before the patients received orthodontic treatment. Fifteen patients who had 2-3 degree root resorption were divided into the experimental group, while 15 patients who didn't have were chosen as control group according to their age and sex. The functional occlusion of the cases in the experimental group and control group was checked on Denar Mark II articulator and via clinical examination, and the indexes of functional occlusion during protrusive and lateral movement in two groups were recorded. SPSS 13.0 software package was used for statistical analysis.
  
  
  RESULTS
  The results showed that the number of anterior teeth occlusal interferences during lateral movement in the experimental group was more than that in control group by clinical (P<0.05) or articulator examination (P<0.05), but the number of posterior teeth occlusal interferences didn't have significant difference between the two groups. There was no significant difference in the retrusive range (RCP-ICP) in vertical, anterior-posterior and lateral direction respectively.
  
  
  CONCLUSIONS
  It is suggested that as a kind of long-standing and minor trauma, the anterior teeth occlusal interferences during lateral movement might be a cause of essential root resorption in anterior teeth.
authors.affiliation: Department of Stomatology, Xiangya Hospital, Central South University, Changsha 410008, Hunan Province, China. chizixia84@126.com
authors.forename: Shu-chi
authors.initials: SC
authors.lastname: Xia
authors.forename: Yan-qin
authors.initials: YQ
authors.lastname: Lu
authors.forename: Noor
authors.initials: N
authors.lastname: Sahibzadi Uzma
authors.forename: Yong-hua
authors.initials: YH
authors.lastname: Lei
mesh_terms: D006801:Humans; D008310:Malocclusion; D011862:Radiography, Panoramic; D012391:Root Resorption