Structural characteristics of bilateral temporomandibular joint disc displacement without reduction and osteoarthrosis are important determinants of horizontal mandibular and vertical ramus deficiency: a magnetic resonance imaging study.

PURPOSE: To estimate in patients with temporomandibular joint (TMJ) arthralgia whether magnetic resonance (MR) imaging findings of bilateral TMJ disc displacement without reduction (DDwoR) and/or osteoarthrosis (OA) are determinants of horizontal mandibular and vertical ramus deficiencies. PATIENTS AND METHODS: Bilateral MR imaging of the TMJ was performed in 68 consecutive patients with TMJ arthralgia to identify those with bilateral TMJ DDwoR and/or OA. Linear and angular cephalometric measurements were performed to apply selected criteria of horizontal mandibular (gonion-menton [Go-Me] <73 mm and articulare-pogonion [Ar-Pog] <105 mm) and vertical ramus (articulare-gonion [Ar-Go] <45 mm) deficiencies. Logistic regression analysis was used to estimate the association between selected MR imaging and cephalometric parameters. RESULTS: In the age- and gender-adjusted analysis, significant increases in the risk of horizontal mandibular (odds ratio, 7.5:1; P = .031) and vertical ramus (odds ratio, 9.5:1; P = .003) deficiencies occurred with bilateral DDwoR and OA. CONCLUSION: In patients with TMJ arthralgia, the MR imaging parameters of DDwoR and OA seem important determinants of horizontal mandibular and vertical ramus deficiencies.

Are temporomandibular joint disk displacements without reduction and osteoarthrosis important determinants of mandibular backward positioning and clockwise rotation?

OBJECTIVE: The aim of this study was to estimate whether, in patients with temporomandibular joint (TMJ) arthralgia, the magnetic resonanace imaging (MRI) findings of bilateral TMJ disk displacement without reduction (DDwoR) and/or osteoarthrosis (OA) are determinants of mandibular backward positioning and/or clockwise rotation. STUDY DESIGN: Bilateral MRI of the TMJ was performed in 50 consecutive TMJ arthralgia patients to identify individuals with bilateral TMJ DDwoR and/or OA. Linear and angular cephalometric measurements were taken to apply selected criteria of mandibular backward positioning (FH to Na-Pog <84°, Na-A-Pog >5°, and SNB <75°) and clockwise rotation (FH to OP >13°, MP to FH >35°, and S-Gn to FH >64°). Logistic regression analysis was used to estimate the association between selected MRI and cephalometric parameters. RESULTS: In the age- and gender-adjusted analyses, significant increases in risk of mandibular backward positioning and clockwise rotation occurred with bilateral DDwoR and OA (9.5:1; P = .040). CONCLUSION: In patients with TMJ arthralgia the MRI parameters of DDwoR and OA seem to be important determinants of mandibular backward positioning and clockwise rotation.

Cephalometric variables discriminate among magnetic resonance imaging-based structural characteristic groups of the temporomandibular joint.

OBJECTIVE: The aim of this study was to assess retrospectively whether, in patients with temporomandibular joint (TMJ) arthralgia, commonly used cephalometric variables of dentofacial morphology can discriminate among magnetic resonanace imaging (MRI)-based TMJ structural characteristic groups of "uni- or bilateral disc displacement without reduction (DDwoR) associated with bilateral osteoarthrosis (OA)" and "uni- or bilateral disc displacement with reduction (DDwR) without OA." STUDY DESIGN: Bilateral MRI of the TMJ was performed in 56 consecutive TMJ arthralgia patients to identify individuals with specific structural characteristic of uni- or bilateral TMJ DDwoR, DDwR, and OA. Application of the criteria resulted in a study group of 31 patients with "uni- or bilateral DDwoR with bilateral OA" and 25 with "uni- or bilateral DDwR without OA." Linear and angular cephalometric measurements were taken from lateral cephalograms to apply selected criteria of dentofacial morphology. One-way analysis of variance was used to assess differences in cephalometric variables by MRI-based TMJ group. Then, discriminant function analysis predicted TMJ group membership. RESULTS: A-B plane to facial plane angle, palatal plane to occlual plane, and interincisal angle produced a significantly discriminant function that predicted TMJ group membership (P < .001). This function correctly classified 85.7% of original grouped cases. CONCLUSIONS: Cephalometric variables may discriminate among MRI-based TMJ structural characteristic groups. Additional diagnostic information related to MRI-based classification groups was generated.