This study investigated properties of the fabricated poly-lactide-co-ε-caprolactone PLCL50）with poly-lactic acid（PLA）and poly-ε-caprolactone（PCL）in an equal ratio and the fibronectin（FN）and albumin（Alb）, immobilized PLCL films, to apply them for barrier membranes for reconstructive bone augmentation. FN is a cell adhesion protein, and Alb is a cell adhesion-inhibiting protein. The contact angle of PLCL50-COOH, FN-PLCL50, and Alb-PLCL50 surfaces with double distilled water significantly decreased than the PLCL50 surface in the evaluation using film surface wettability analysis. The presence of fibronectin and albumin on PLCL50 films was demonstrated by X-ray photoelectron spectroscopy analysis（XPS）. The number of cells attached to FN-PLCL50 films was more significant than those attached to the Alb-PLCL50 and PLCL50 films after 90 min and 3 days of culture. On the other hand, immobilizing albumin on the PLCL50 surface resulted in a significant decrease in attached cells after 90 min and 3 days. The quantification of mineralization of osteoblast MC3T3-E1 cells on FN-PLCL50 films was significantly higher than that of Alb-PLCL50 and PLCL50 films after 7, 14 and 21 days in the results of alizarin red staining and mineralization assay. The morphological differences in the attached MC3T3-E1 cells on FN-PLCL50, Alb-PLCL50 and PLCL50 were imaged by scanning electron microscopy . After 90 min, 3 and 7 days of culture, the attached MC3T3-E1 cells on the FNPLCL50 films were more spread than those on the Alb-PLCL50 and PLCL50 films. These results suggested that fibronectin and albumin effectively performed biological activities on PLCL50 films of osteoblast-like cells.

The use of high-volume intra-oral suction（HVIOS）is effective in reducing droplets and aerosols during dental treatment. However, there are few reports on the effects of different uses of HVIOS on droplets and aerosols. We examined the differences in the generation of droplets and aerosols with HVIOS. The teeth were scaled and ground. The number of droplets and aerosols associated with different uses of HVIOS was evaluated by settle plate sampling, aerosol particle measurement, and high-speed camera photography. The number of bacterial colonies in front of the dentist was significantly reduced when a HVIOS was placed at the left side of the mouth compared to when it was not used. In tooth grinding, on the dental care workers’ side, the group in which HVIOS was not used had the largest preoperative and postoperative differences for all particle sizes, followed by those placed at the left side of the mouth and placed at the labial side of the maxillary anterior teeth. Photographic images did not show white foglike spreads in front of the dentist and near the dentist’s side compared to other usages. We suggest that HVIOS is effective when it is placed at the left side of the mouth to reduce large particles in front of and near the dentist during tooth scaling and to prevent exposure to dental care workers during cutting of the maxillary anterior tooth.

Brushing with a toothbrush is effective for removing oral biofilms. However, toothbrushes can be a source of infectious diseases after use. Recently, the environmental impacts of plastics, such as marine pollution, have become an issue. This includes the disposal of plastic toothbrushes. Consequently, bamboo toothbrushes, with a low environmental impact, have become widely-used as alternatives. Although there are many reports on the hygiene of plastic toothbrushes after use, there are few reports on bamboo toothbrushes. Thus, we compared the hygiene of bamboo toothbrushes with those of plastic and biomass plastic toothbrushes after use and storage. Three types of toothbrushes were immersed in bacterial cultures and washed, and the number of bacteria on the toothbrushes after 12 and 24 h of storage was examined. The number of bacteria on the bamboo toothbrushes immediately after immersion was significantly higher than on the other two types, but this number was 95–99％ lower after 12–24 h of storage. No differences were observed for different bacterial species（Actinomyces oris and Streptococcus mutans）or different storage conditions（wet and dry）. However, pre-wetting before immersion significantly reduced the number of bacteria on the bamboo toothbrushes. These results indicate that the hygienic conditions of bamboo toothbrushes after 12–24 h of storage were comparable to those of plastic or biomass toothbrushes. Furthermore, pre-wetting the bamboo toothbrushes before use improved hygiene immediately after use. Bamboo toothbrushes are a better choice as they provide equivalent hygiene to that of plastic toothbrushes and also have a low environmental impact.