Comparative Evaluation of Depth of Cure between Two Bulk-fill Composites and a Conventional Resin Composite: An In Vitro Study

Abstract

Aim and objective To evaluate and compare the depth of cure of two bulk-fill composites with a conventional composite. Materials and methods A sample size of 36 was taken and divided into three groups based on the type of composite. Standardized cylindrical stainless steel molds were prepared with 8 mm diameter and 10 mm depth. Measurement of depth of cure by the scraping method was performed according to the ISO 4049 (2009). After placing the specimens, the mold was pressed with polyester strips covered by glass slides and curing was initiated using Bluephase 20i (Ivoclar Vivadent US) light-curing unit through the glass slide. Immediately after curing, the specimens were removed from the mold and the uncured part of the specimens was removed by scraping with a plastic spatula. The absolute length of the hardened composite specimen was measured using a digital vernier caliper. The measured length was divided by two and recorded as the ISO depth of cure. Results The depth of cure of the composite specimens was found to be higher for Voco Xtra Fil bulk-fill composite than for Shofu Beautifil bulk-fill composite and Filtek Z350 XT conventional composite (3M/ESPE). Conclusion Within the limitations of the study, it can be concluded that the placement of bulk-fill composites with 3-mm increments is mandatory for complete curing. Clinical significance Depth of cure of bulk-fill composites determines the adaptation of restoration to the tooth structure, and this study aims to evaluate two newly introduced bulk-fill composites using scrape test. How to cite this article Bastian M, Vineet RV, Mathew J, et al. Comparative Evaluation of Depth of Cure between Two Bulk-fill Composites and a Conventional Resin Composite: An In Vitro Study. Cons Dent Endod J 2020;5(2):23–27.

Depth of Cure of Bulk-fill Resin Composites with Different Photo-initiator Systems Cured by Monowave and Polywave Light Curing Units

“…52 To measure DOC of RBCs, a number of techniques have been suggested, such as measuring the bottom and top surfaces' microhardness or degree of conversion at various depths until an 80% bottom/top ratio is reached, removing the uncured material from the specimen with solvents, and manually scraping (SCR) the uncured material. 9,5 In the current study, DOC was evaluated by ISO scraping test technique. The ISO 4049 standard outlines a basic technique for measuring DOC.…”

“…29 Vaseline was applied to the internal surface of the mold by a microbrush for the easy removal of the specimens after curing. 5 A Mylar strip was placed over a 1 mm thick glass microscope slide and mold was placed on it. The material was packed in one increment into the mold, the top was covered by another Mylar strip and glass slide, and to ensure consistent packing of the specimens, a load of 0.5 Kg was applied to the glass slide for 60 seconds.…”

“…DOC of the examined materials was measured according to ISO 4049 method 49 .The uncured part of the samples was scraped with a plastic spatula. 5 After that, a digital caliper was used to measure the cylindrical specimen of hardened composite resin's absolute length in millimeters (Figure 1). Three measurements were recorded for each single specimen and the average was calculated.…”

“…1 The top and bottom hardness ratio, top and bottom degree of conversion ratio, removal of the uncured polymer from the sample with solvents, and manual scraping (SCR) (ISO 4049 standard) of the uncured material are several methods that have been suggested to measure the DOC. 5,9 A simple method has been described in the ISO 4049 49 standard and is based on a measurement with micrometer of the RBC thickness that remains following removal of soft, unpolymerized material with a plastic spatula. 20,23 According to several studies, there is no significant difference observed irrespective of the variations in photo-initiators inside the examined RBCs, that indicate the major effect of LCU was not significant.…”