Preheating of dental composite resins: A scoping review

Abstract

Objective: The aim of this scoping review was to analyze the available evidence on the preheating process and its effects on physicochemical properties of composite resins. Materials and Methods:A systematic search was performed in August 2021 using PubMed/Medline, Embase, Scopus, and ISI Web of Science databases and gray literature without language or date restriction. Inclusion criteria were in vitro studies that assessed the physicochemical properties and marginal adaptation of preheated composite. Exclusion criteria were studies with experimental composite, literature reviews, clinical studies. Data from selected studies were qualitatively analyzed.Results: In total, 104 studies were found from which 39 were included. The most used composite resin was Filtek Z350 XT (3 M/ESPE), preheated at 68 C in a Calset device (AdDent Inc., Danbury, CT, USA) for 5 or 15 min. Most studies showed decreased viscosity, increased conversion degree and microhardness of composite resins, and better marginal adaptation of direct and indirect restorations. Also, flexural strength was not affected, and data about bond strength were inconclusive due to heterogeneity among studies. Conclusion:The parameters used for preheating composite resins are heterogeneous. Preheating decreased viscosity, increased the conversion degree and microhardness of composite resins, and improved the marginal adaptation of direct and indirect restorations.Clinical Significance: The analysis of evidence showed a high heterogeneity among preheating protocols. Preheating may benefit the handling and physicochemical properties of composite resins.

Preheating and “snow‐plow” composite application technique affect double bond conversion but not bond strength to dentine

“…Even if the same light-curing unit was used in DC and MTBS measurements, the data should still be interpreted separately due to these Unlike in previous reports, 13,14 this study considered whether instrument preheating may prevent rapid cooling of the preheated composite. A negligible effect of the preheated instrument was found on the preheated bulk-fill composite.…”

“…The temperatures further decreased to 38–40°C between 15 and 30 s post‐placement which is commonly time during which sculpting is completed and light‐curing commences. Unlike in previous reports, 13,14 this study considered whether instrument preheating may prevent rapid cooling of the preheated composite. A negligible effect of the preheated instrument was found on the preheated bulk‐fill composite.…”

“…Although not a new concept, preheating of resin composites has recently attracted attention of researchers and clinicians. Several properties of resin composites were shown to improve with preheating, such as increased conversion and microhardness, adhesion, decreased viscosity, and polymerization shrinkage 13,14 but the quality of polymerization was somewhat inconsistent. [15][16][17] Marginal adaptation of preheated bulk-filled composites in Class II cavities depended on the preheating temperature and light-curing mode, potentially reducing microleakage.…”

Color and Translucency Variation of a One-Shaded Resin-Based Composite after Repeated Heating Cycles and Staining

“…Even though preheating of the resin composite is not mandatory, the advantages of this procedure have been proven from a clinical point of view [ 22 ]. In addition, preheating of the resin-based composites is indicated by some manufacturers.…”

“…RBCs can be used at room temperature or warmer by heating the syringes or mono-doses in heating units (Calset, ENA Heat, Ease-it) at 54–68 °C [ 20 , 21 ]. Due to a larger delivery system than mono-doses, syringes are preheated several times in daily practice [ 22 ]. Preheating RBCs reduces the viscosity and stickiness and improves the handling of materials [ 23 , 24 , 25 , 26 ], which leads to an improved marginal adaptation to enamel and dentin, minimizing the risk of secondary caries [ 27 , 28 ].…”