RESUMO
BACKGROUND: Retention after orthodontic tooth movement (OTM) is essential to prevent relapse. This study examined the effects of a fixed orthodontic device and Nano Calcium Carbonate (CaCO3) nanoparticles with or without recombinant human bone morphogenetic protein (rhBMP) on rat body weight. MATERIALS AND METHODS: OTM was administered for 21 days to 80 Wistar Albino rats. First molar mesialization was active then forming two 40-rat groups which were subdivided into four subgroups of 10 rats each. These subgroups received 5 µg/kg rhBMP, 75 µg/kg CaCO3, 80 µg/kg rhBMP-loaded CaCO3 and one control. The relapse rate was examined weekly over the second 21 days when the second group exhibited mechanical retention and the first did not. Group 1 rats were murdered after 21 days (day 42), whereas group 2 rats entered a third 21-day post-retention period and then murdered (day 63). BW and OTM were measured on days 1, 21, 28, 35, 42, and 63. RESULTS: Within each group, the animal body weight was reduced significantly after the intervention and continued over time with a higher average reduction in the 9-week group than the 6-week group. However, there were no significant (P-value Ë0.05) differences in the BW between the groups of the two (6-week and 9-week) sets and the subgroups of the 6-week set across each time point. In contrast, there was a significant (P-value Ë0.05) difference between the BW of the conjugate subgroup and the other three subgroups in the 9-week set, particularly on 63rd day. CONCLUSION: CaCO3 nanoparticles and/or BMP with orthodontic treatment collectively or individually cause a reduction of body weight in rats.