title: Comparison of excursive occlusal force parameters in post-orthodontic and non-orthodontic subjects using T-Scan® III.
abstract: OBJECTIVE
  Published studies indicate that orthodontically treated patients demonstrate increased posterior occlusal friction contributing to temporomandibular disorder (TMD) symptoms. This study investigated measured excursive movement occlusal contact parameters and their association with TMD symptoms between non- and post-orthodontic subjects.
  
  
  METHODS
  Twenty-five post-orthodontic and 25 non-orthodontic subjects underwent T-Scan® computerized occlusal analysis to determine their disclusion time (DT), the excursive frictional contacts, and occlusal scheme. Each subject answered a TMD questionnaire to determine the presence or absence of TMD symptoms. Statistical analysis compared the within group and between group differences (p < 0.05).
  
  
  RESULTS
  Statistically significant differences were observed in the disclusion time: DT = 2.69 s in the post-orthodontic and 1.36 s in the non-orthodontic group. In the non-orthodontic group, 72.7% working and 27.3% non-working side contacts were seen, while in the post-orthodontic group, (near equal) 54.7% working and 45.3% non-working side contacts were seen. Presence of canine guidance was seen in 60% of the non-orthodontic group and 24% in the post-orthodontic group. Seventy-two percent of the post orthodontics subjects presented with one or more TMD symptoms.
  
  
  CONCLUSIONS
  Significantly longer disclusion time, higher posterior frictional contacts, and more TMD symptoms were observed in the post-orthodontic group, suggesting that orthodontic treatment increases posterior tooth friction. Computerized occlusal analysis is an objective diagnostic tool determining the quality of excursive movements following orthodontic treatment.
authors.affiliation: a Faculty of Dentistry, Department of Prosthodontics and Occlusion , Thammasat University , Pathum Thani , Thailand.
authors.forename: Sarah
authors.initials: S
authors.lastname: Qadeer
authors.affiliation: a Faculty of Dentistry, Department of Prosthodontics and Occlusion , Thammasat University , Pathum Thani , Thailand.
authors.forename: Ahmed A
authors.identifier: http://orcid.org/0000-0001-9484-2687
authors.initials: AA
authors.lastname: Abbas
authors.affiliation: a Faculty of Dentistry, Department of Prosthodontics and Occlusion , Thammasat University , Pathum Thani , Thailand.
authors.forename: Lertrit
authors.initials: L
authors.lastname: Sarinnaphakorn
authors.affiliation: b Department of Restorative Dentistry , Tufts University School of Dental Medicine , Boston , MA , USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Kerstein
mesh_terms: D000293:Adolescent; D000328:Adult; D001732:Bite Force; D003766:Dental Occlusion; D005260:Female; D017276:Friction; D006801:Humans; D007574:Jaw Relation Record / Q000295:instrumentation*; D008297:Male; D009971:Orthodontics, Corrective; D011795:Surveys and Questionnaires; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology*
keywords: T-Scan; TMD; disclusion time; excursive movements; frictional contacts; orthodontic treatment