Purpose: The purpose of this study was to analyse the correlation between the presence of temporomandibular joint (TMJ) effusion and limitation of mouth opening after arthroscopic surgery.Methods: The authors studied 88 joints in 86 patients with TMJ disorders who underwent lysis and lavage in the superior space of the TMJ. The patients were referred for magnetic resonance (MR) imaging before and after surgery. The joints were divided into two categories based on the presence of TMJ effusion. Chi-square tests were used to evaluate differences between distributions for these two groups. The alpha level was set to 0.05.Results: The number of joints with effusion decreased after surgery. However, after surgery, there was no significant difference between the distributions of TMJ effusion for TMJs with and without limitation of mouth opening.Conclusion: The amount of joint effusion in the temporomandibular joint decreased after surgery, but the effusion did not completely disappear even after the clinical symptoms improved. It was suggested that the joint effusion naturally accumulates in a vacant space, the upper joint space located in the lateral recess.
Purpose: The purpose of this study was to evaluate the extension of bleaching effect by linearly measurement on the crosscut surfaces of bleached teeth in vitro.Methods: Thirty extracted bovine incisors were stained by black tea and were divided three groups in each of ten. The labial surface was bleached using an in-office bleaching material for 0, 3, and 6 times respectively. Then, teeth were crosscut and color was measured in bleached and not bleached area linearly from enamel surface to pulpal dentin to obtained CIE L*a*b* values using a digital camera with CIE XYZ color gamut (RC500). And whiteness index (WID) was calculated from those values.Results: Both 3-times and 6-times bleaching showed the bleaching effect and 6-times bleaching extended the effect deeper than 3-times bleaching. Three samples of 3-times bleaching group and one sample of 6-time bleaching group showed less bleaching effect at enamel dentin junction (EDJ). In 3-times and 6-times bleaching groups, WID of enamel was statistically higher than those of shallower and deeper dentin.Conclusion: It was concluded that bleaching effect was extended deeper along with dentinal tubules beyond EDJ.
Purpose: The recent development of enamel-colored translucent zirconia makes it a viable material to produce crowns. However, to achieve a sufficient surface roughness for bonding, alumina particle abrasion must be employed. In this study, the effects of particle abrasion on the surface roughness of zirconia and the effects of sample pretreatment on the bond strength between zirconia and a composite resin core were investigated and compared to optimize the surface treatment conditions.Methods: Zirconia specimens were abraded with alumina particles and bonded to trial composite resin cores using a dual-cure composite luting agent and either an alumina-zirconia adhesive primer and/or a porcelain primer. The particle abraded zirconia surface was observed via laser scanning microscopy, and the roughness was evaluated qualitatively.Results: The peak-to-valley roughness, arithmetic mean height, root mean square height, and skewness parameter values significantly increased after particle abrasion. The bond strength was greater when the adhesive primer was applied to the zirconia specimens, and when the porcelain primer and a self-etching primer were applied to the composite resin cores, compared with specimens prepared without primers. With a self-etching primer, however, the porcelain primer played no role in increasing the bond strength.Conclusion: The combination of particle abrasion and a suitable primer is recommended to improve the bond strength between zirconia and the composite resin core. Moreover, the chemical surface treatment with a self-etching primer was more effective for adhesion than the silane coupling of the composite resin fillers.