The effect of blood contamination on microleakage of several restorative materials
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Introduction: Isolation in dentistry is a very important step to avoid the adverse effects of contamination and, therefore microleakage. Class V restorations can present microleakage in the occlusal or gingival margins depending on the restorative material and technique used to restore the preparation. Objectives: The purpose of this study is to evaluate the effect of blood contamination on the microleakage of class V preparations of teeth restored with five different restorative materials. Materials and Methods: One hundred class V cavity preparations were prepared in 50 de-identified extracted human molars. Class V preparations were prepared on both the mesial and distal surface of each tooth. Five materials were used to restore the cavity preparations. Each tooth served as both an experimental specimen (contaminated with human blood), and a control, bringing the number of restorations to 20 for each material. Five materials were used to restore the cavity preparations. Prepared teeth were randomly divided into five groups of 10 teeth each, according to the type of restorative materials used: amalgam (Valiant PhD-XT), resin composite (Tetric EvoCeram), glass ionomer (Fuji IX), resin-modified glass ionomer (Fuji II LC), and tri-silicate cement (Biodentine). The restorations were then finished with abrasive discs (Sof-Lex, 3M/ESPE, St. Paul, MN) and stored overnight at 37° C and 100% relative humidity. The specimens were then thermocycled for 500 cycles in distilled water at 5° C and 55° C with a dwell time of 30 seconds in each bath. All specimens were placed in 0.5% basic fuchsin (Acros Organics, New Jersey NJ) aqueous solution at room temperature for 24 hours. They were then removed from the dye solution, washed with tap water, air dried and polished with Polycril (Mdc Dental, Jalisco, México) using a rag wheel in order to eliminate any flash material. The specimens were sectioned buccolingually, embedded in acrylic resin and sectioned axially three times across each restoration with a low-speed diamond saw. Dye penetration was scored for the occlusal and the gingival margins using stereomicroscope. Results: The results for microleakage at the occlusal location of the contaminated site indicates that Biodentine had no leakage (0%). This was significantly different from the results for other materials. The overall Pearson chi-square statistic was 24.826 (df = 4, p < 0.001). The results for leakage at the gingival location of the contaminated site indicate that Biodentine was significantly different from the other dental materials (chi-square = 26.655, df = 4, p < 0.001). Conclusions: Within the limitations of this in vitro study, it can be concluded that microleakage was greater in the occlusal and gingival margins for both resin composite and resin modified glass ionomer class V restorations if contaminated with blood. Amalgam and Fuji IX showed less microleakage in comparison to resin based materials. Calcium tri-silicate cement was the most resistant to microleakage and does not appear to be affected by human blood contamination.