title: Effect of early Class II treatment on the incidence of incisor trauma.
abstract: BACKGROUND
  Many researchers have examined the prevalence of dental injuries in children and adolescents. The purpose of this study was to examine the prevalence and incidence of incisor trauma in subjects who participated in a randomized clinical trial designed to investigate early growth modifications in the treatment of Class II malocclusion.
  
  
  METHODS
  The subjects were randomized to 3 treatment groups during the initial phase of the study: (1) headgear or biteplane, (2) bionator, and (3) observation (no treatment). All 3 groups underwent phase 2 treatment with fixed appliances. Incisor injury was scored at every data collection point with the Ellis index by a blinded examiner using dental casts, intraoral photos, and panoramic and periapical x-rays.
  
  
  RESULTS
  Twenty-five percent of the subjects had incisor trauma at the baseline examination, and 28% experienced new or worsening maxillary incisor injury during the study. No significant differences were found with regard to sex and prevalence of injury at baseline. No differences in incidence of trauma were found between the 3 treatment groups throughout the study (P = 0.19); however, boys were more likely to experience maxillary incisor injury (odds ratio estimate, 2.37; 95% CI, 1.33, 4.21), and those with an injury at baseline were more likely to experience an additional injury (odds ratio estimate, 1.81; 95% CI, 1.03, 3.17).
  
  
  CONCLUSIONS
  Early orthodontic treatment did not affect the incidence of incisor injury. The majority of the injuries before and during treatment were minor; therefore, the cost-benefit ratio of orthodontic treatment primarily to prevent incisor trauma is unfavorable.
authors.affiliation: Department of Biostatistics, University of Florida, Gainesville, FL, USA
authors.forename: David R
authors.initials: DR
authors.lastname: Chen
authors.forename: Susan P
authors.initials: SP
authors.lastname: McGorray
authors.forename: Calogero
authors.initials: C
authors.lastname: Dolce
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Wheeler
mesh_terms: D000202:Activator Appliances; D002508:Cephalometry; D002648:Child; D003743:Dental Enamel / Q000293:injuries; D003782:Dental Pulp / Q000293:injuries; D003804:Dentin / Q000293:injuries; D005115:Extraoral Traction Appliances; D005260:Female; D005431:Florida / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007180:Incisor / Q000293:injuries*; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000628:therapy*; D011446:Prospective Studies; D016300:Radiography, Bitewing; D011862:Radiography, Panoramic; D012737:Sex Factors; D019228:Tooth Crown / Q000293:injuries; D014082:Tooth Fractures / Q000453:epidemiology; D016388:Tooth Loss / Q000453:epidemiology; D014092:Tooth Root / Q000293:injuries; D019553:Tooth, Nonvital / Q000453:epidemiology; D057832:Watchful Waiting