Background: The purpose of this study was to determine whether periodontal residents could enhance their ability to assess the pain levels experienced by their patients from probing, using visual analog scale (VAS) to record pain. We hypothesized that with increasing experience by repeated comparisons of the patients' VAS pain ratings with independent ratings by the residents, they would improve their ability to assess their patients' pain experiences. Methods: For each of three periodontal residents, 40 consecutive patients with periodontal disease were asked to express the degree of pain they experienced during the probing. Independently, the residents rated the pain levels they perceived that the patients experienced. Subsequently, the residents compared the two VAS ratings and discussed differences in ratings with the patients. Descriptive statistics and intraclass correlation coefficients were used to analyze the findings. Results: Differences between patients' and residents' VAS scores gradually became smaller over time for two of the residents. Results for the third resident were less compelling. Conclusions: This study indicated that the training program improved the residents' ability to estimate the pain experiences of their patients, at least for two of the three participating residents. This training program, using periodontal probing as a model, could serve as an educational tool for students and practitioners who want to improve their sensitivity to their patients' pain experiences.

The response of osteoblastic cells to a thin film of poorly crystalline calcium phosphate apatite crystals (PCA) was examined in vitro. The PCA thin film was prepared on polystyrene culture dishes using highly metastable calcium phosphate ion solution at low temperatures. The PCA thin film was formed through fusion and transformation of granular calcium phosphate particles, which had initially formed on the surface, into a film of calcium phosphate apatite crystal. The PCA thin film was used for cell culture without additional surface treatment. The osteoblastic cell behaviors including adhesion, proliferation, expression of the marker genes, and calcified matrix formation were examined on the PCA thin film using primary osteoblasts or MC3T3-E1 cells. The cells were well attached and had spread in a slender shape over the PCA thin film. The extent of cell proliferation on the PCA thin film is as much as on the plain dishes. In addition, a much larger number of calcified nodules had formed on the PCA thin film than on the plain dish. The expression of the marker genes such as alkaline phosphatase, osteocalcin, osteopontin, osteonectin was apparent. These results demonstrate that the osteoblasts exhibit a full spectrum of cellular activity including the adequate differentiation on the PCA thin film. Therefore, a PCA thin film can be used as a coating material for biomaterials where the surface is not adequate for inducing the full activity of bone cells.