Aim: The aim of the study was to evaluate the effect of posterior teeth extraction on the type of intrinsic muscles' fibers of the tongue.
Methodology: 28 healthy adult male albino rats weight range 150 to 200 gm were randomly divided into 4 groups as following: group I: control 4 weeks, group II: control 8 weeks, group III: bilateral mandibular molars extraction and euthanized after 4 weeks and group IV: bilateral mandibular molars extraction and euthanized after 8 weeks. Tongues were dissected for histological, histomorphometic, gene expression analysis, and ultrastructure examination via transmission electron microscope.
Results: The histological examination of group III showed deterioration in tongue muscles, with areas of spacing between muscle bundles, increased perimysium connective tissue, together with dilated and congested blood. Group IV showed improvement in histological features of muscles together with signs of hypertrophy. Morphometric analysis revealed a significant increase in (mean total area percent of muscle fibers, area of single muscle fiber, perimeter of single muscle fiber and minimum Feret's diameter) in group IV in addition to significant decrease in number of inflammatory cells as compared to group III. Additionally, transmission electron microscopic imaging revealed mitochondrial degeneration together with a statistically significant increase in length of sarcomere and length of I-band in group III. Further a statistically significant increase in width of sarcomere and width of Z-line in addition to increase in Cox IV gene and PGC-1 alpha gene expression was observed in group IV as compared to the other groups.
Conclusions: The current study had shown that bilateral mandibular molar extraction had a great impact on intrinsic muscles of the tongue.