Objective :To evaluale the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of differeat thickness to the 0.2mm thick aluminum oxide.Methods:Ten alumium axide disks were randomi...Objective :To evaluale the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of differeat thickness to the 0.2mm thick aluminum oxide.Methods:Ten alumium axide disks were randomized into 2 groups.Each of five disks was veneered with Vita Lumin Shade B4 porcelain of thickness of 0.4mm and 0.6mm respectively.The L*a*b* color notations of the substrate covered with non-veneered disks and 2 thickness porcelain veneered disks were measured separtely and the color differences(ΔE) were calculated.Results:Statistically significant differences in color coordinates of dark substrates were recorded after the sustrate was covered by an aluminum oxide disk and also after the addition of veneering porcelain to the alumimum axide disks in group 1(P=0.0002) and group 2(P=0.0075) and between 2 groups(P=0.0001).Conclusion:The ability of masking underlying discoloration was increased and shifted to gray when the thickness of veneering porcelain increased.展开更多
Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temp...Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. Methods Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. Results The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. Conclusions The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.展开更多
文摘Objective :To evaluale the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of differeat thickness to the 0.2mm thick aluminum oxide.Methods:Ten alumium axide disks were randomized into 2 groups.Each of five disks was veneered with Vita Lumin Shade B4 porcelain of thickness of 0.4mm and 0.6mm respectively.The L*a*b* color notations of the substrate covered with non-veneered disks and 2 thickness porcelain veneered disks were measured separtely and the color differences(ΔE) were calculated.Results:Statistically significant differences in color coordinates of dark substrates were recorded after the sustrate was covered by an aluminum oxide disk and also after the addition of veneering porcelain to the alumimum axide disks in group 1(P=0.0002) and group 2(P=0.0075) and between 2 groups(P=0.0001).Conclusion:The ability of masking underlying discoloration was increased and shifted to gray when the thickness of veneering porcelain increased.
文摘Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. Methods Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. Results The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. Conclusions The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.
