Predictors of early postoperative pneumonia after oncologic surgery with the patients receiving professional oral health care: A prospective, multicentre, cohort study.

This study was a prospective, multicentre, cohort study on 685 patients who had undergone oncologic surgery. The patients were divided into two groups according to the presence or absence of postoperative pneumonia. The two groups were compared with respect to their background, index operation, food eaten, oral condition, contents of oral care and dental treatment, laboratory data, and bacterial flora. All postoperative pneumonias occurred in six cases within four days postoperatively. The multivariable logistic regression analysis showed that preoperative serum C-reactive protein was the strongest predictor of postoperative pneumonia. In addition, decreased postoperative Candida albicans colonies was an effective predictor of postoperative pneumonia. For patients with predictors of postoperative pneumonia, perioperative strategies for its prevention should be considered in addition to professional oral health care. This study was approved by the National Hospital Organization's Central Ethics Review Board and was also approved by the directors of the participating institutions.

Limited mouth opening with a square mandible configuration: a case of masticatory muscle tendon-aponeurosis hyperplasia.

Most clinicians throughout the world are probably unaware of the existence of masticatory muscle tendon-aponeurosis hyperplasia (MMTAH), potentially leading to misdiagnoses such as temporomandibular joint disorder (TMD). Here, we introduce this disease from the viewpoint of education. In February 2013, a 39-year-old woman presented with limited mouth opening. Her facial configuration was characterized by a square mandible. There was no evidence of TMD. Magnetic resonance imaging (MRI) showed bilateral enlargement of the masseter muscles. Additionally, a 'thick' aponeurosis of the anterior aspect of the masseter muscle was noted bilaterally. On maximal mouth opening, intraoral palpation along the anterior border of the masseter muscle confirmed a hard cord-like structure, consistent with the findings on MRI. MMTAH was diagnosed. When clinicians notice limited mouth opening on oral examination, they should be knowledgeable about diseases associated with limited mouth opening and a square mandibular configuration, such as MMTAH.

Functional role of acetylcholine and the expression of cholinergic receptors and components in osteoblasts.

Recent studies have indicated that acetylcholine (ACh) plays a vital role in various tissues, while the role of ACh in bone metabolism remains unclear. Here we demonstrated that ACh induced cell proliferation and reduced alkaline phosphatase (ALP) activity via nicotinic (nAChRs) and muscarinic acetylcholine receptors (mAChRs) in osteoblasts. We detected mRNA expression of several nAChRs and mAChRs. Furthermore, we showed that cholinergic components were up-regulated and subunits/subtypes of acetylcholine receptors altered during osteoblast differentiation. To our knowledge, this is the first report demonstrating that osteoblasts express specific acetylcholine receptors and cholinergic components and that ACh plays a possible role in regulating the proliferation and differentiation of osteoblasts.

Nicotine induces cell proliferation in association with cyclin D1 up-regulation and inhibits cell differentiation in association with p53 regulation in a murine pre-osteoblastic cell line.

Recent studies have suggested that nicotine critically affects bone metabolism. Many studies have examined the effects of nicotine on proliferation and differentiation, but the underlying molecular mechanisms remain unclear. We examined cell cycle regulators involved in the proliferation and differentiation of MC3T3-E1 cells. Nicotine induced cell proliferation in association with p53 down-regulation and cyclin D1 up-regulation. In differentiated cells, nicotine reduced alkaline phosphatase activity and mineralized nodule formation in dose-dependent manners. Furthermore, p53 expression was sustained in nicotine-treated cells during differentiation. These findings indicate that nicotine promotes the cell cycle and inhibits differentiation in association with p53 regulation in pre-osteoblastic cells.

Experimental tooth movement through mature and immature bone regenerates after distraction osteogenesis in dogs.

The purpose of this study was to verify the influence of tooth movement on tooth roots and periodontal tissues when teeth were moved into mature, well-organized, and mineralized regenerate bone created after distraction osteogenesis compared with immature, fibrous, and less-mineralized bone. Six 15-month-old male beagles underwent 10 mm of bilateral mandibular distraction osteogenesis. After 2-week (group 1) and 12-week (group 2) consolidation periods, third premolars were moved distally into the regenerate bone with 100 g of orthodontic force for 12 weeks. Simultaneously, second premolars were also moved distally as controls. After completion of tooth movement, the experimental animals were killed, and their tissues were harvested for histological evaluation. When premolars in groups 1 and 2 were compared, group 1 showed higher rates of tooth movement until the eighth week of experimental tooth movement (P <.05). The amount of tooth movement was significantly greater in group 1 than in group 2 or in the control teeth (P <.05). In group 1, we observed considerable root resorption extending into the dentin, and the thickness of the dentin became approximately half that of the controls at the compression side adjacent to the distraction gap. This root resorption extended from the cementoenamel junction to the root apex. In group 2, root resorption on the compression side reached the dentin, but the root resorption was less than in group 1. These results indicated that heavy force and early orthodontic tooth movement are not recommended when teeth are moved through regenerated bone created by distraction osteogenesis, to avoid tipping and severe root resorption.