Effect Of Gluma Desensitizer On Postoperative Hypersensitivity In Crown Prosthetics

Cutting tooth structures is a basic operation in complete crown restorations. In this procedure, a large number of dentinal tubules may be exposed, leading to various degrees of dentin hypersensitivity (DH). These opened tubules allow bacteria and their toxin products to penetrate in, which correlated with pulpal disease. The pulp also gets an acute damage, and it will take a relative long time to recover. So it has been suggested that applying desensitizing agents on prepared tooth surfaces can avoid complications during the interim stage, while the restorations are fabricated, and also before cementation. Gluma desensitizer is usually applied to treat ordinary DH and reported with good effect. But unfortunately there are little reports answer these questions: whether it still has good desensitizing effect on sensitivity caused by complete crown preparation, and whether it affects crowns' retention. All of these uncertainty hampered its widespread use in clinical. PURPOSEThis research investigated the effect of Gluma desensitizer not only on the bond strengths to dentin of two dentinal cements commonly used in clinical but also on reducing the postoperative sensitivity, and totally evaluated Glumadesensitizer's practicability in the field of crown prosthetics. MATERIALS AND METHODSFreshly extracted human molars were cut occlusally to obtain flat dentin surfaces. All the teeth were distributed into control group (placebo) and Gluma group. Testing specimens made of Nickel-Chromium alloy were bonded to dentin surfaces by polycarboxylate and Vitremer resin-modified glass ionomer cement. Tensile bond strength (TBS) and shear bond strength (SBS) of the samples were tested using a universal testing machine. Vital human molars were cut occlusally to expose flat dentin surfaces immediately after extraction, treated with Gluma desensitizer, prepared and observed under SEM. A clinical trial used self-paired design, warm sterile water as placebo and visual analog scale (VAS) to investigate the effect of applied Gluma on sensitivity of abutment teeth after crown preparation. RESULTS1. Application of Gluma desensitizer increased the TSB and SBS of Vitremer luting, and the differences were statistically significant (P<0.05). The TBS and SBS of polycarboxylate were also slightly increased, but the change in TBS has no statistical significance (P>0.05). Most of the debond modes in this study were "mixed" interface failure.2. With the observation under SEM, the dentinal tubule orifices were opened by mechanical exposing with non-treatment, but blocked after pretreatment using Gluma desensitizer.3. Gluma desensitizer decreased dentin sensitivity with significant difference between the pre- and post-treatment groups, and the VAS scores also differed in post-treatments from the control groups (PO.05). Its efficientrate is 83.87%. CONCLUSIONSThe results indicated: Gluma desensitizer can effectually seal the dentinal tubules. It has no negative impacts on the retention of crowns bonded by Vitremer luting and polycarboxylate, also can it improve the bond strength of Vitremer luting. Furthermore, Gluma desensitizer can effectively release DH after crown preparation. In short, the characteristic of convenience and inexpensiveness makes it feasible of Gluma desensitizer to be used as a routine application in crown restoration and makes it be an attribution to completing the prosthetic therapy with "no pain".