Objective

To clarify the tryptophanyl-tRNA synthetase （WRS） production release from lower respiratory tract cells by the infection of oral bacteria and it’s immunological responsiveness.

Methods

A549 were used as lower respiratory tract epithelial cells. The bacterial strains used were Staphylococcus aureus ATCC 25923 and Streptococcus sanguinis ATCC 10556. The WRS expressions from A549 stimulated with both bacteria were analyzed by western blotting. Cellular destruction was investigated by lactate dehydrogenase （LDH） activity. The gene （TNF-α, IL-6, IL-8, CCL2, and E-selectin） expressions from A549 stimulated with recombinant WRS （rWRS）were analyzed by quantitative PCR. The effects of polymyxin B （PMB）-treated rWRS, heat-treated rWRS, or co-stimulated with rWRS, and peptidoglycan （PGN） were also investigated.

Results

In the culture supernatant, WRS was observed after stimulation with Staphylococcus aureus and an increase in LDH activity, simultaneously. However, the WRS gene expression did not change significantly. The expression of all target genes were significantly upregulated. These inducing activities were not inhibited by PMB that decreased to control levels by heat treatment and increased additively by PGN co-stimulation.

Conclusion

These results suggest that WRS released from lower respiratory tract epithelial cells by the upper respiratory resident bacterial influx into the lower respiratory tract could be a host factor inducing inflammatory responses. Keywords: Staphylococcus aureus, human alveolar epithelial cells （A549）, tryptophanyl-tRNA synthetase （WRS）, inflammatory response

Oral Microorganisms produce various inflammatory diseases such as periodontal disease, caused by Porphyromonas gingivalis, and denture stomatitis, caused by Candida albicans, due to aging or weakened immunity. Although mouthwash has been currently used for chemical plaque control, the effect of mouthwashes is still controversial. The purpose of this study was to evaluate the efficacy of mouthwashes against P. gingivalis and C. albicans.

P. gingivalis and C. albicans were rinsed with several kinds of mouthwashes, and proliferation was evaluated. Microorganisms were cultured on resin blocks, the blocks were washed with several types of mouthwash, and adherent microorganisms were collected to evaluate viability.

Under the mouthwash mimic condition, a mouthwash containing cetylpyridinium chloride （CPC）significantly inhibited the growth of both types of microorganisms compared to other mouthwashes （p < 0.05）. Under the denture cleaning situation, a CPC-containing mouthwash significantly inhibited the growth of P. gingivalis and C. albicans compared to other mouthwashes （p < 0.05）.

These results suggest that mouthwashes containing cetylpyridinium chloride should be effective in preventing various diseases caused by oral microorganisms, such as periodontitis and denture stomatitis.

The purpose of this study was to evaluate the efficacy of mechanical cleaning using a titanium brush and subsequent autogenous bone grafting for the treatment of peri-implantitis.

The peri-implant bone recovery rate was calculated using the thread or length of the implant as an index on pre- and postoperative dental radiographs. In these evaluation methods, the Mann Whitney U test was used to compare the peri-implant bone recovery rates before and after surgery. In the evaluation method using the threaded portion of the implants as the index, the mean preoperative peri-implant bone level for all implants was 59.5 ± 9.4%, whereas the mean bone level at six months or longer after the implant-supported dental prosthesis was placed postoperatively was 90.6 ± 9.4%. In the evaluation using the implant length as the index, the mean preoperative bone level of the implants was 54.2 ± 10.9%, whereas the mean bone level at six months or longer after the postoperative placement of the implant-supported dental prosthesis was 83.7 ± 9.0. These findings suggest that the postoperative bone level was significantly higher than the preoperative level. These results indicate that mechanical cleaning with a titanium brush and subsequent autogenous bone grafting are effective treatments for peri-implantitis.

In this study, we examined the extent to which occlusal force affects the phenomenon of overlapping that occurs during superimposition using an intraoral scanner.

Forty participants with natural, healthy dentition were enrolled. A TRIOS3 intraoral scanner was used to scan the right lateral first premolar to second molar areas of the upper and lower jaws. During interocclusal registration scanning, participants were instructed to “bite normally,” “bite lightly,” and “bite strongly,” to obtain data for three occlusion patterns. The STL data for each occlusal condition was analyzed using an image analysis software program to calculate the number of occlusal contact points, and the volume of overlapping images of the occlusal surface.

In the conventional method that used vinyl silicone impression materials, the number of occlusal contact points were calculated. In both optical and conventional methods, the number of occlusal contact points increased with occlusal force, and significant differences were observed among the occlusal conditions （P<0.05）. Moreover, with respect to volume of overlapping images of the occlusal surface, the strong bite showed significantly larger values than the normal and weak bites （P<0.05）.

The results of this study reveal that the stronger the occlusal force, the larger the volume of the overlapping area.