IADR Abstract Archives
Effects of Actn3 KO on Tooth and Alveolar Bone Morphology
Objectives: ACTN3 577XX genotype results in absence of the α-actinin-3 protein in osteoblasts, diminished bone mass and bone mineral density. ACTN3XX also contributes to the development of skeletal class II malocclusions, presumably through diminished mandibular bone growth. Effects of ACTN3 genotype on development and health of teeth or alveolar bone have not been investigated.
Methods: We studied the effects of Actn3-/- in 47 female mice at 2 different age groups (3-months and 25/30-months) for differences in mandibular molar, incisor and alveolar bone morphology and mineral density by microCT analysis. Individual teeth and alveolar bone surrounding the molars were segmented as individual volumes of interest for analysis. Dental and limb bone phantoms were used for standardization of tissue mineral density.
Results: There were no significant differences for molar teeth. 3 month KO incisors had significantly reduced total volume (mm^3) (p=0.029) and 25-30 month very significantly reduced total volume (p=0.0007). Object surface (mm^2) was also decreased in KO incisors at (p=0.0463) in 3 month and (p=0.0049) in 25-30 month, producing rounder cylindrical shape. Alveolar bone total volume surrounding the molars was decreased approximately 20% in 3 month KO (p=0.03) and 25% in 25-30 months (p=0.02). Alveolar bone trabecular surface was decreased proportionally to bone volume in KO. Alveolar bone mineral density (gm/cm^3) was reduced in all KO (p=0.04).
Conclusions: Actn3-/- mice have smaller and more rounded incisor dimensions and reduced alveolar bone mineral density, mass and trabeculation. ACTN3 genotype may contribute to susceptibility for bone loss during periodontitis or orthodontic tooth position relapse. Since mice have continuously erupting incisors, dimension differences observed might not occur in humans.
Methods: We studied the effects of Actn3-/- in 47 female mice at 2 different age groups (3-months and 25/30-months) for differences in mandibular molar, incisor and alveolar bone morphology and mineral density by microCT analysis. Individual teeth and alveolar bone surrounding the molars were segmented as individual volumes of interest for analysis. Dental and limb bone phantoms were used for standardization of tissue mineral density.
Results: There were no significant differences for molar teeth. 3 month KO incisors had significantly reduced total volume (mm^3) (p=0.029) and 25-30 month very significantly reduced total volume (p=0.0007). Object surface (mm^2) was also decreased in KO incisors at (p=0.0463) in 3 month and (p=0.0049) in 25-30 month, producing rounder cylindrical shape. Alveolar bone total volume surrounding the molars was decreased approximately 20% in 3 month KO (p=0.03) and 25% in 25-30 months (p=0.02). Alveolar bone trabecular surface was decreased proportionally to bone volume in KO. Alveolar bone mineral density (gm/cm^3) was reduced in all KO (p=0.04).
Conclusions: Actn3-/- mice have smaller and more rounded incisor dimensions and reduced alveolar bone mineral density, mass and trabeculation. ACTN3 genotype may contribute to susceptibility for bone loss during periodontitis or orthodontic tooth position relapse. Since mice have continuously erupting incisors, dimension differences observed might not occur in humans.