Bone Abstracts

Purpose: Osteoradionecrosis (ORN) of the mandible is a serious complication of radiation therapy, and accompanies soft tissue damage before bone loss appears. However, there is still no adequate treatment to heal the soft tissue damage of ORN. This study investigated the effect of platelet-derived growth factor (PDGF) or rat mesenchymal stem cells (rMSCs) on the healing of radiation-induced soft tissue injury by varying administration timing.Methods: Rat...

Objectives: Sex hormones and mechanical overload have been regarded as main causative factors in the pathogenesis of temporomandibular joint (TMJ) osteoarthritis. However, there was no report regarding the relevance of mechanical overload on the mandibular condyle with serum estrogen level. This study aimed to investigate changes of the mandibular condyle of TMJ in ovariectomized rat under increased loading, and to evaluate the inhibitory effect of systemic administration of 1...

Introduction: Low-magnitude, high-frequency (LMHF) mechanical stimuli lead to enhance bone formation and decrease resorption. This study aimed to investigate the effect of vibration on the bone loss induced by inflammatory cytokine, lipopolysaccharide (LPS).Methods and designs: Balb-C mice were administered to LPS (5 mg/kg) with two i.p. injections on days 0 and 4, while sham control group was injected with 400 μl of water for injection without LPS....

Bisphosphonates (BPs) are widely used as antiresorptive drugs. However, one of most potent BPs, zoledronic acid (ZA) can cause BP-related osteonecrosis of the jaws (BRONJ) with a poorly understood pathophysiology. The aim of this study was to find a clue for the development of BRONJ by evaluating the cytotoxic effects of ZA on osteoblasts and examining the action mechanism of ZA on osteoclast differentiation. Jaw bone osteoblasts (JB-OBs), long bone osteoblasts (LB-OBs), and b...

Introduction: Low level of estrogen has regarded as a main contributing factor of temporomandibular joint (TMJ) arthritis in young women patients. However, there is lack of evidence about the occurrence of arthritis in knee joint (KJ) related with estrogen deficiency. This study aimed to investigate the effect of estrogen deficiency on the loaded and non-loaded bone area of TMJ or KJ.Method and materials: Total of 28 SD rats were allocated into two group...

Sustained release of bone morphogeneic protein (BMP)-2 by heparin-contained biomaterials is advantageous for bone tissue regeneration using low dose BMP-2. However, its effect in high dose BMP-2 is still unclear and should be clarified considering the clinical use of high dose of BMP-2 in spine and oral surgery. This study aimed to evaluate the efficacy of heparin-conjugated collagen sponge (HCS) in high dose BMP-2 delivery by investigating in vivo initial osteogenic regulatio...

Bisphosphonates (BPs) are widely used for treating osteoporosis and preventing osseous metastasis or hypercalcemia in cancers. However, osteonecrosis of the jaw in patients treated with BP after dentoalveolar surgery has been increasing, especially in those treated with strong BPs such as zoledronate (ZA). The pathobiology underlying the occurrence of osteonecrosis only in the jaw bone remains unclear. The objective of this study was to compare the effects of BPs on the in...

Purpose: The purpose of this study was to investigate the bony change of mandibular condyle when the originally less-loaded or unloaded surface was subjected to functional loading by the newly designed animal experiment, and to evaluate whether this experiment is adequate for the animal model of condylar resorption due to mechanical loading.Methods: Twelve adult male New Zealand white rabbits were used. Unilateral oblique vertical body osteotomy (UOVBO) ...

Purpose: Osteoradionecrosis (ORN) of the mandible is a serious complication of radiation therapy, and preceded by soft tissue damage before bone loss appears. However, there is still no adequate treatment to heal the soft tissue damage of ORN. This study investigated the effect of PDGF-BB or mesenchymal stem cells (rMSCs) on radiation-induced soft tissue injury.Methods: Rat model was designed to irradiate the skin of SD rats while sparing the body and in...

Introduction: Estrogen therapy decreases circulating levels of sclerostin, a protein product of SOST which increase in postmenopausal women. However, the mechanisms of estrogen on the expression of SOST remain unclear. This study was hypothesized that estrogen modulates SOST expression by interfering bone morphogenic protein (BMP) signaling on the basis that BMP is an inducer of SOST in osteoblasts.Description of methods: We investigated the expression o...