Study of the tidemark in human mandibular condylar cartilage.

OBJECTIVES

The tidemark is the junction of mature calcified and uncalcified articular cartilage. Metabolic activity in the tidemark area makes this structure important in articular remodelling and osteoarthrosis. However, detailed study of the tidemark on the mandibular condyle has been limited. This study investigated the functional significance of the tidemark in the mandibular condyle with respect to load-bearing.

DESIGN

The study sample included 87 healthy human mandibular condyles from subjects aged 14-76 years. The morphology, number, and thickness of tidemarks were observed and measured in the anterior, superior, and posterior regions. Five additional mandibular condyles were evaluated by scanning electron microscopy.

RESULTS

The tidemark appeared in 80 specimens as a dense wavy line at the interface between the calcified and hypertrophic layers of the condylar cartilage. Scanning electron microscopy showed a highly wavy tidemark surface in the load-bearing areas and a relatively flat and smooth surface in the non-load-bearing areas. The thickness of the tidemark in the load-bearing areas was significantly higher than that in the non-load-bearing areas (P=0.003).

CONCLUSION

The results of this study demonstrated that the thickness of the tidemark was related to load-bearing on the articular surface.