RESUMEN
This study evaluated the influence of operator's age and experience with dental operating microscope (DOM) on the cleaning of post space walls and on bond strength of glass fiber posts associated with self-adhesive resin cement. Sixty bovine roots were selected. Root canal preparation was performed and roots were filled using gutta-percha/AH Plus. For post space preparation, specimens were divided into four groups (n = 15), according to operator's age and the use of DOM: (1) ≥40 years; (2) ≥40 years with magnification; (3) <40 years; (4) <40 years with magnification. Next, a high-speed bur of the post system and torque-controlled round burs were used for cleaning of post space. Five roots in each group were evaluated for the degree of cleanliness under a stereo microscope using a scoring system. In the remaining 10 specimens from each group, glass fiber posts were cemented with RelyX U200. Two slices (1 ± 0.1 mm) prepared on each root third of all specimens were evaluated by push-out analysis. The scoring system was analyzed using Kruskal-Wallis and push-out data using ANOVA. Significance level was set at 5%. No significant difference was observed in cleaning scores among groups (p > .05). There was no significant difference when comparing the groups and the root thirds (p > .05). The adhesive failure between dentin, cement, and post predominated in all groups. Operator's age and experience with DOM did not influence the cleanliness of root canal walls or the bond strength of glass fiber posts associated with self-adhesive resin cement for post space preparation. RESEARCH HIGHLIGHTS: Although magnification is considered part of Endodontics, little is known about the variables associated. Operator's age and experience with microscope on cleaning of canals and on push-out of posts with self-adhesive resin cement were evaluated.
Asunto(s)
Recubrimiento Dental Adhesivo , Técnica de Perno Muñón , Animales , Bovinos , Cavidad Pulpar , Dentina , Vidrio/química , Ensayo de Materiales , Cementos de Resina/químicaRESUMEN
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.