The application of fractal dimension to temporomandibular joint sounds.

Researchers have attempted to use mathematical analysis of the sounds produced by symptomatic temporomandibular joints (TMJ) as a diagnostic modality. However, previous studies have generally concluded that such analyses have little diagnostic utility. Previous studies using Fourier transforms and visual inspection were of limited success. This paper reports the results of a preliminary retrospective study using fractal analysis to analyze sounds produced by symptomatic temporomandibular joints previously diagnosed using other clinical modalities as having internal derangements with reducing discs. Multiple mandibular opening and closing cycles were recorded in four subjects. The study revealed that fractal analysis produced a high degree of reproducibility within, and similarity across subjects. The fractual dimension associated with joints having this pathology was found to be 1.266, revealing that fractal analysis shows promise as a noninvasive method for diagnosing interarticular TMJ pathology.