The number of osteoblasts and osteoclasts in hypofunctional teeth during orthodontic tooth movement in rats

Background: When moved orthodontically, hypofunctional teeth will have a decreased tooth movement rate compared to normal teeth. This study aimed to determine the number of osteoblasts in the tension side and the number of osteoclasts in the pressure side of the hypofunctional teeth during orthodontic tooth movement. Method: 18 male Wistar rats were given a palatal coil spring application on the maxillary incisors. Rats were divided into two groups, the orthodontic group with normal occlusion (NO) and hypofunctional occlusion (HO). The number of osteoblasts on the tension side and osteoclasts on the pressure side on days zero (D ₀), five (D ₅), and 10 (D ₁₀) were tested with two-way ANOVA. Observations were made by hematoxylin eosin staining. Result: The results showed that the number of osteoblasts on the tension side of the HO group was the same at the NO group (p> 0.05). The number of osteoblasts on the tension side in the NO and HO groups at D ₅ was the same at D ₁₀ (p = 0.99), but significantly higher (p = 0.002), than D _0. The number of osteoclasts on the pressure side in the HO group was significantly lower than the NO group (p <0.05). The number of osteoclasts in the NO D ₅ group was significantly higher than the other groups (p <0.05). Conclusions: The number of osteoblasts on the tension side was not affected by the hypofunctional state but decreased the number of osteoclasts on the pressure side during orthodontic tooth movement.