Effects of GLUMA Desensitizer and Low-Level 980 nm Diode Laser on the Retention of the Metal Frames of the PFM Crowns Cemented by Self-adhesive Resin Cement (RelyX U200).

Introduction: Sometimes, dentinal tubules are exposed to the oral cavity during the preparation of vital teeth for crowns, and patients show various signs of tooth hypersensitivity. Some treatments have been suggested for dental hypersensitivity after tooth preparation, such as low-level diode laser (980 nm) and GLUMA desensitizer. The pretreatment of dentin with desensitizers may affect retention. The aim of this study was to ascertain the effects of the 980nm Diode laser and GLUMA Desensitizer on the retention of the metal frames cemented by self-adhesive resin cement (RelyX U200). Methods: Thirty intact permanent maxillary first premolars were used in this study. After preparing teeth with 0.5 to 0.7 finishing line above CEJ, casting full metal crowns with a 5-diameter ring on the occlusal surface was done. Then the samples were divided into 3 groups: (1) Control Group (n=10), (2) 980 nm diode laser (n=10), and (3) GLUMA desensitizer (n=10). Frames were cemented with self-adhesive resin cement (RelyX U200) and the bond strength was measured by universal testing machine. Data were analyzed by ANOVA and Tukey post hoc tests in SPSS version 25 (P<0.05). Results: Frame retention in the 980 nm diode laser group (40.90±27.07N) was significantly lower than the control group (138.17±40.81 N) and the GLUMA desensitizer group (318.59±56.31N) (P<0.05), and frame retention in the GLUMA Desensitizer group was significantly higher than the other groups (P<0.05). Conclusion: The GLUMA desensitizer has a positive effect and the 980 nm diode laser has a negative effect on the retention of frames cemented by self-adhesive resin cement (RelyX U200).