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Background: Intermittent parathyroid hormone (PTH) can be used to treat osteoporosis of the spine and hip. However, whether it can be used to treat osteoporosis of the mandible is unclear. The purpose of this study was to explore the influence of applying intermittent PTH to ovariectomized rats on the trabecular bone microarchitecture of the mandible and femoral head.Methods: Eighteen female rats were divided into three groups: the healthy group, ovariectomized (OVX) group, and OVX + PTH group. The OVX group and OVX + PTH group had an OVX at 8 weeks of age. The OVX + PTH group received intermittent PTH therapy for 12 weeks. The mandibles and femurs of all rats were removed at 20 weeks and were then scanned using microcomputed tomography (micro-CT).Results: From the micro-CT analysis, the trabecular bone microarchitecture of the mandible and femoral head are offered as follows: (1) The bone volume fraction and trabecular thickness in the OVX group were lower than those in the healthy group. (2) The bone volume fraction and trabecular thickness in the OVX + PTH group approximated those in the healthy group.Conclusion: The conclusions of this study regarding the trabecular bone microarchitecture of the mandible and femoral head are offered as follows: (1) The BV/TV and TbTh in the OVX group were lower than those in the healthy group. (2) The BV/TV and TbTh in the OVX + PTH group approximated those in the healthy group, therefore, intermittent PTH displayed high efficacy for treating femoral or mandibular deterioration of bone microstructure resulting from loss of ovarian function. Osteoporosis of the femur or mandible in the rats was ameliorated by intermittent PTH therapy. [ABSTRACT FROM AUTHOR]

Chemical manipulations of the implant surface produce a bactericidal feature to prevent infections around dental implants. Despite the successful use of bismuth against mucosal and dermis infections, the antibacterial effect of bismuth in the oral cavity remains under investigation. The aim of this study was to evaluate the antibacterial activities of bismuth compounds against Actinobacillus actinomycetemcomitans, Staphylococcus mutans, and methicillin-resistant Staphylococcus aureus (MRSA), and to investigate the antimicrobial effects of bismuth doped micro-arc oxidation (MAO) titanium via an agar diffusion test. Cell viability, alkaline phosphatase activity, and mineralization level of MG63 osteoblast-like cells seeded on the coatings were evaluated at 1, 7, and 14 days. The results demonstrate that bismuth nitrate possess superior antibacterial activity when compared with bismuth acetate, bismuth subgallate, and silver nitrate. The bismuth doped MAO coating (contained 6.2 atomic percentage bismuth) had good biological affinities to the MG63 cells and showed a higher antibacterial efficacy against Actinobacillus actinomycetemcomitans and MRSA, where the reduction rates of colony numbers is higher than that of the control group by 1.5 and 1.9 times, respectively. These in vitro evaluations demonstrate that titanium implants with bismuth on the surface may be useful for better infection control. [ABSTRACT FROM AUTHOR]

Abstract: This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744 patients were screened to obtain 123 samples for this study. All permanent mandibular first molars were evaluated in axial sections from the pulpal floor to the apices of the roots to determine the number of roots. The interorifice distances from the distolingual (DL) canal to the mesiobuccal (MB) and distobuccal (DB) canals were also estimated. The prevalence of permanent three-rooted mandibular first molars was 33.33%, with a bilateral incidence of a symmetrical distribution of 53.65%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence.The mean interorifice distances from the DL canal to the DB, MB, and ML canals of the permanent three-rooted mandibular molars were 2.7, 4.4, and 3.5 mm, respectively. The high prevalence of the DL root in permanent mandibular first molars among the Taiwanese (Chinese) population and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments. [Copyright &y& Elsevier]