Evaluation of the dimensions, morphology, and position of the mandibular condyles in individuals with neurofibromatosis 1: a case-control study

Objectives: The aim of this study was to evaluate the mandibular condyles of neurofibromatosis 1 (NF1) individuals without facial plexiform neurofibroma using cone beam computed tomography images.

Materials and methods: Eighty cone beam computed tomography scans (160 mandibular condyles) were analyzed: 40 from NF1 individuals (study group) and 40 from individuals without NF1 (control group). The anteroposterior and mediolateral dimensions, height, and volume of the mandibular condyles were measured. The mandibular condyles were classified according to their morphology: healthy (absence of morphological changes), with flattening (loss of rounded contour of at least one of the surfaces), with erosion (loss of continuity of the cortical bone), with osteophyte (exophytic formation of the condyle surface), and with sclerosis (any increase in the cortical thickness in the load-bearing areas). Furthermore, the position of the mandibular condyles in relation to the joint fossa in an anteroposterior view was classified as anterior, concentric, or posterior.

Results: The study group had a higher anteroposterior dimension of the mandibular condyles compared with the control group (p < 0.05). There were no differences in condylar morphology and position between both groups (p > 0.05). The morphological alterations were not associated with sex or age in any group evaluated (p > 0.05). For both groups, the concentric position was the most common. For the study group, there was a significant difference in the condylar position between the sides (p < 0.05).

Conclusions: NF1 individuals without facial plexiform neurofibroma present a high prevalence of condyles with a large anteroposterior dimension and asymmetric position in the joint fossa. However, no morphological and volumetric changes were observed in the mandibular condyles of them.

Clinical relevance: The knowledge of the TMJ alterations in individuals with NF1 is important to establish an evaluation protocol, which would allow early intervention if indicated.