Three-dimensional visualization and quantification of the mandibular articular surface by optical profilometry

The aim of this study was to introduce a nondestructive optical technique f or the quantitative assessment of natural biological surfaces as demonstrat ed with the example of the articular surface of the human temporomandibular joint. The computer-assisted quantitative evaluation of the surface is rea lized by the aquisition of three-dimensional images via the optical techniq ue of phase measuring profilometry. After mathematical processing of the da ta set the resulting image can be visualized as three-dimensional object su rface reconstructions or as grid surfaces from which arbitrary sections may easily be extracted. From such single sections we can calculate a value th at represents the degree of height deviations of the section profile and ca n be regarded as a parameter for the surface roughness. Further quantitativ e information about the surface topography is provided by the Fourier trans form analysis of the profiles. The Fourier spectrum contains information a bout the spatia I distribution of roughness-causing protuberances along the overall surface. As an example one healthy condyle and one remodeled condy le from macerated cadaver mandibles were investigated. For the two samples evaluated we calculated a mean surface roughness of the entire articular su rface with a value of 0.03 +/- 0.005 mm for the healthy condyle with its sm ooth surface and a value of 0.14 +/- 0.009 mm for the remodeled condyle. We recommend optical profilometry as a sophisticated technique for a more obj ective and quantitative pathological classification of articular surfaces a nd similar objects.