Salivary Cortisol and Salivary Flow Rate in Clinical Types of Oral Lichen Planus.

Patients with oral lichen planus (OLP) may develop immune sialadenitis that causes a dry mouth. The role of cortisol in autoimmune diseases is well known; yet studies on this subject are controversial. In this study, the salivary flow rate and salivary cortisol level were compared among subtypes of OLP. This study involved three groups of patients: (1) 11 with reticular OLP, (2) 20 with atrophic-erosive OLP, and (3) 30 with no apparent oral lesion. The salivary flow rate in the control group was significantly higher than in OLP patients. The mean level of cortisol in atrophic-erosive cases was higher than in reticular cases and in the control group; however, there was no significant difference between the three study groups. In a previous study, there was moderate to severe acinar atrophy in two-thirds of patients with OLP, which may explain the decreased salivary flow rate in these patients.

Comparative Study of the Shear Bond Strength of Flowable Composite in Permanent Teeth Treated with Conventional Bur and Contact or Non-Contact Er:YAG Laser.

INTRODUCTION: The aim of this study was to evaluate and compare the in vitro effect of the Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser with different radiation distances and high-speed rotary treatment on the shear bond strength of flowable composite to enamel of human permanent posterior teeth. METHODS: freshly extracted human molar teeth with no caries or other surface defects were used in this study (n=45). The teeth were randomly divided into 3 groups. Group 1: treated with non-contact Er:YAG Laser and etched with Er:YAG laser, Group 2: treated with contact Er:YAG Laser and etched with Er:YAG laser, Group 3 (control): treated with diamond fissure bur and etched with acid phosphoric 37%. Then the adhesive was applied on the surafces of the teeth and polymerized using a curing light appliance. Resin cylinders were fabricated from flowable composite. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. RESULTS: The amount of Shear Bond Strength (SBS) in the 3 treatment groups was not the same (P<0.05).The group in which enamel surfaces were treated with diamond fissure bur and etched with acid (conrtol group) had the highest mean shear bond strength (19.92±4.76) and the group in which the enamel surfaces were treated with contact Er:YAG laser and etched with Er:YAG laser had the lowest mean shear bond strength (10.89±2.89). Mann-whitney test with adjusted P-value detected significant difference in shear bond strength between the control group and the other 2 groups (P < 0.05). CONCLUSION: It was concluded that both contact and non-contact Er:YAG laser treatment reduced shear bond strength of flowable resin composite to enamel in comparison with conventional treatment with high speed rotary. Different Er:YAG laser distance irradiations did not influence the shear bond strength of flowable composite to enamel.