Effect of desensitizer on shear bond strength of adhesive system / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of desensitizer on shear bond strength of adhesive system.</p><p><b>METHODS</b>Twenty specimens were made and divided randomly into an experiment group and a control group. In the experiment group, the dentin bonding surface was applied with Green Or and in the control, the dentin bonding surface was untreated. The IPS-Empress specimens were bonded to the dentin bonding specimens using Variolink II adhesive system. The shear bond strength of all testing samples was determined with Instron testing machine. The surfaces of the drawing sections were observed using the scanning electron microscope (SEM).</p><p><b>RESULTS</b>The shear bond strength of the experimental group and the control group was (5.53 +/- 0.96) MPa and (7.32 +/- 1.34) MPa respectively and there was statistically significant difference between two groups (P = 0.003). In the experimental group, adhesive failure was the most prevalent type of failure, while in the control group, cohesive failure was the most prevalent type.</p><p><b>CONCLUSIONS</b>The application of Green Or on the dentin bonding surface decreased the shear bond strength between dentin and IPS-Empress specimens when using Variolink II adhesive system.</p>

Quantitative study on occlusal balance of normal occlusion in intercuspal position / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To assess occlusal balance of normal occlusion in intercuspal position with maximal bite force.</p><p><b>METHODS</b>Maximal bite force was recorded in intercuspal position by use of T-Scan II system from 123 subjects with normal intact dentitions. Occlusal balance of normal occlusion was quantitatively analyzed from center of force, percentage of bite force, and occlusal contacts.</p><p><b>RESULTS</b>The relative position of the center of bite force, the difference in bilateral force percentage, and unsymmetrical coefficient followed normal distributions. The 95% reference ranges for corresponding testing items were -6.60 to 6.68 mm, -15.50% to 12.10%, and 0.65 to 1.39. There was no statistic difference (P = 0.915) in occlusal contacts between left and right sides. The 98.4% of normal occlusion subjects had the center of bite force locating in posterior region of dentition when biting with maximal force in intercuspal position.</p><p><b>CONCLUSIONS</b>Occlusal balance could be evaluated by T-Scan II system. Occlusion of normal subjects biting with maximal force was stable and bilaterally balanced in intercuspal position.</p>