title: Disc displacement without reduction: a retrospective study of a clinical diagnostic sign.
abstract: OBJECTIVE
  The purpose of this retrospective study is to evaluate a clinical diagnostic sign for disc displacement without reduction (DDWR), the absence of additional condylar translation during opening compared with protrusion.
  
  
  METHODS
  Thirty-eight electronic axiographic and magnetic resonance imaging (MRI) examinations of the TMJ were analyzed in order to compare the opening/protrusion ratio of condylar translation between non-painful DDWR and non-DDWR.
  
  
  RESULTS
  According to the Mann-Whitney U test, the opening/protrusion ratio in non-painful DDWR differs significantly from non-DDWR (p < 0.0001).
  
  
  CONCLUSIONS
  Among non-painful DDWR, there is no additional condylar translation during opening in comparison with protrusion, and this is probably also the case for DDWR without limited opening, which is a subtype that has not been validated by the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Comparative condylar palpation can analyze this sign, and therefore, further comparative investigations between MRI and clinical examination are needed to validate the corresponding clinical test.
authors.affiliation: a Faculté d'Odontologie , Aix Marseille Université , Marseille 13005 , France.
authors.forename: Anne
authors.initials: A
authors.lastname: Giraudeau
authors.affiliation: a Faculté d'Odontologie , Aix Marseille Université , Marseille 13005 , France.
authors.forename: Marion
authors.initials: M
authors.lastname: Jeany
authors.affiliation: b Faculté d'Odontologie , Université de Nice Sophia-Antipolis , Nice 06357 , France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Ehrmann
authors.affiliation: a Faculté d'Odontologie , Aix Marseille Université , Marseille 13005 , France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Déjou
authors.affiliation: c Faculty of Odontology , Monastir University , Monastir 5019 , Tunisia.
authors.forename: Imed
authors.initials: I
authors.lastname: Ouni
authors.affiliation: a Faculté d'Odontologie , Aix Marseille Université , Marseille 13005 , France.
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Orthlieb
mesh_terms: D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D008279:Magnetic Resonance Imaging; D008297:Male; D010173:Palpation; D012189:Retrospective Studies; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D055815:Young Adult
keywords: Adhesion and TMD; Clinical diagnosis and TMD; Degenerative changes and TMD; Disc displacement without reduction; Evaluation of condylar translation using axiography; Internal derangement of temporomandibular joint; Magnetic resonance imaging and TMD