Influence of Using Clinical Microscope as Auxiliary to Perform Mechanical Cleaning of Post Space: A Bond Strength Analysis

Abstract

Introduction: The aim of the present study was to evaluate the influence of using a clinical microscope while performing mechanical cleaning of post space walls on the bond strength of a fiberglass post to dentin.

Methods: Forty-five bovine roots were used. After preparation, roots were filled using gutta-percha and Pulp Canal Sealer (SybronEndo, Orange, CA). Subsequently, for post space preparation, the roots were divided into 3 groups: control (only heat condenser + specific bur of the post system); cleaning without a microscope, mechanical cleaning (after the procedure described in the control group, round burs were used to improve cleaning); and cleaning with a microscope, mechanical cleaning performed with round burs visualized under a clinical microscope. Then, fiberglass posts were cemented. The roots were prepared and evaluated by the push-out test. Data were analyzed using Kruskal-Wallis and Student-Newman-Keuls tests (P < .05). The failure pattern was classified as follows: adhesive between the cement and dentin, adhesive dentin/cement/post, mixed cohesive within dentin, mixed cohesive post, and mixed cohesive post/dentin.

Results: The bond strength values (mean ± standard deviation) were control (cervical 1.17 ± 1.1, middle 0.40 ± 0.3, apical 0.52 ± 0.3, and total 0.95 ± 1.9), cleaning without a microscope (cervical 1.66 ± 2.3, middle 0.65 ± 1.1, apical 0.79 ± 1.2, and total1.04 ± 1.7), and cleaning with a microscope (cervical 3.26 ± 2.8, middle 1.97 ± 3.5, apical 1.85 ± 4.1, and total 2.37 ± 3.5). In the cleaning with a microscope group, the bond strength values were significantly higher than those in the other groups. In all groups, the main failure pattern was adhesive between cement and dentin.

Conclusions: The use of a clinical microscope while performing mechanical cleaning during post space preparation improved the bond strength of a fiberglass post to dentin.

Keywords: Bond strength; clinical microscope; mechanical cleaning; post space walls.