Marginal accuracy of provisional crowns using three material systems and two techniques: A scanning electron microscope study.

Talib Amin Naqash,Muhammad Waqar Hussain,Mohammed Alfarsi

doi:10.12669/pjms.35.1.5

Talib Amin Naqash, Muhammad Waqar Hussain + Show 1 more

Open Access

https://doi.org/10.12669/pjms.35.1.5

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Abstract

Objective:The most important desideratum of a provisional crown is an adequate marginal fit that is essential for maintaining optimal periodontal health, reducing the sensitivity of freshly prepared dentin and protection of the pulp. The purpose of this in vitro study was to compare the vertical marginal accuracy of provisional crown materials using three different material systems (chemically activated PMMA powder-liquid system, light activated UDMA single paste system, and chemically activated Bis-GMA two paste auto mix system) and two different techniques (direct and indirect).Methods:Two customized stainless steel dies, simulating prepared and unprepared tooth were used to fabricate 40 provisional crowns. Additional silicone elastomeric impression and a vacuum-formed polypropylene sheet were used as a matrix. Ten crowns, each of the three material systems used in the study (n = 10 × 3) were fabricated using the direct technique and ten crowns from chemically activated PMMA powder-liquid system (n = 10 × 1) using an indirect technique. Scanning electron microscope (SEM) was used to measure vertical marginal discrepancies at x100 magnification. The results were analyzed using descriptive statistics and comparisons between various groups were made using one way analysis of variance (ANOVA) after checking the normality of data using Shapiro Wilk’s Test. Post Hoc Tukey HSD Test was used to determine the statistical difference between the means of independent group pairs.Results:The mean marginal discrepancies of Bis-GMA composite resin, UDMA composite resin, and PMMA acrylic resin using direct technique were 67.15 µm, 71.01 µm, and 84.56 µm respectively. PMMA acrylic resin showed a mean marginal discrepancy of 103.03 µm using the indirect technique.Conclusion:This study has shown that provisional crowns fabricated with Bis-GMA composite resin material (two paste auto mix system) registered the best marginal accuracy. Provisional crowns fabricated with indirect technique recorded less marginal opening than with direct technique.

Highlights

IntroductionProvisional (interim/ temporary) restorations are used to safeguard and sedate the pulp of prepared abutments, promote periodontal healing and health, rehabilitate oral function, provide positional stability, evaluate parallelism of abutments, and enhance esthetics.[1,2,3] Interim coverage of a prepared tooth during various stages of treatment is an important step in the fabrication of fixed dental
Marginal accuracy is one of the most important factors that determines the success of a provisional restoration; an acceptable accuracy at the margin is indispensable in maintaining gingival health and protecting the tooth from physical, chemical, bacterial, and thermal injuries.[4]
In the Polymethyl methacrylate (PMMA) direct technique, the marginal discrepancy was found to be maximum with mean value 103.03±3.47, while for Bis-phenol A glycidyl methacrylate (Bis-GMA) direct technique the marginal discrepancy was found to be minimum with mean value 67.15±1.81

Summary

Introduction

Provisional (interim/ temporary) restorations are used to safeguard and sedate the pulp of prepared abutments, promote periodontal healing and health, rehabilitate oral function, provide positional stability, evaluate parallelism of abutments, and enhance esthetics.[1,2,3] Interim coverage of a prepared tooth during various stages of treatment is an important step in the fabrication of fixed dental. Marginal accuracy is one of the most important factors that determines the success of a provisional restoration; an acceptable accuracy at the margin is indispensable in maintaining gingival health and protecting the tooth from physical, chemical, bacterial, and thermal injuries.[4] Marginal failure might lead to micro-leakage, postoperative sensitivity, pulpal inflammation, recession, and recurrent dental caries.[5]. The material system and the fabrication technique involved influence the marginal accuracy of the provisional restorations. The techniques commonly used for fabrication of interim restorations include direct and indirect techniques

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