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Keywords:

  • temporomandibular joint;
  • osteoarthritis;
  • cartilage;
  • MMPs;
  • temporomandibular disorder

Objective

To investigate the pathological effects on temporomandibular joint cartilage of an experimentally created unilateral anterior crossbite prosthesis.

Methods

Six-week-old female Sprague–Dawley rats were divided into experimental and control groups and further divided into three subgroups for three time points (n = 9). In experimental groups, the unilateral anterior crossbite was created by bonding two metal tubes on left maxillary and mandibular incisors. 2, 4, or 8 weeks after operation, the histomorphological changes and the expression changes of PCNA, COL II, aggrecan, MMP-3, MMP-9, MMP-13, and TIMP-1 in condylar cartilage were investigated by hematoxylin–eosin and toluidine blue staining, real-time PCR, and immunohistochemistry.

Results

In experimental groups, decreasing in chondrocytes, cell-free areas, reduction in the thickness of hypertrophic layer, and loss of extracellular matrix were noticed. The expression level of PCNA was decreased at week 2 and week 4. The mRNA expression of COL II was decreased at 4 week and that of aggrecan was increased at 2 week but decreased at 4 and 8 week. The expression of MMP-9, MMP-13, and TIMP-1 was increased at 2-week and decreased at 4- and 8-week, while that of MMP-3 was increased at 4- and 8-week.

Conclusions

The present unilateral anterior crossbite prosthesis led to degradation of mandibular condylar cartilage.