A recent study published in Scientific Reports investigated the clinical performance of proximal restorations using bulk fill composite with repeated preheating. The double-blinded clinical trial, conducted at the Conservative Dentistry Department of Cairo University, assessed whether preheating the composite material multiple times affected the integrity and longevity of dental restorations over a 24-month period.
The study enrolled 84 patients aged 20-45 years with class II cavities in molar teeth. Participants were divided into four groups: a control group receiving non-heated bulk fill composite, and three intervention groups where the composite was preheated one time, five times, or ten times before application. The composite was heated to 68°C using a Therma-Flo™ Composite Warming Device. Restorations were evaluated at 6, 12, 18, and 24 months using modified US Public Health Service (USPHS) criteria.
The primary outcome was marginal integrity, assessed using Alpha, Bravo, Charlie, and Delta scores. Alpha and Bravo scores were considered clinically acceptable, while Charlie and Delta scores indicated the need for replacement. Statistical analysis revealed no significant differences between the groups in terms of marginal integrity or other clinical parameters throughout the 24-month follow-up period.
Impact of Preheating on Restoration Performance
The results indicated that repeated preheating of the bulk fill composite did not compromise the clinical performance of the restorations. According to the researchers, preheating the composite material enhances its flowability and adaptation to cavity walls, potentially improving the quality of the restoration. The study's findings suggest that clinicians can preheat bulk fill composite multiple times without concerns about negatively affecting the restoration's longevity.
Materials and Methods
The materials used in the study included X-tra fil® bulk fill composite (VOCO, Cuxhaven, Germany), Futurabond M+® universal adhesive bonding agent (VOCO), and 37% phosphoric acid etchant gel (Eco-etch ®, IvoclarVivadent, Liechtenstein). Cavity preparation followed minimally invasive dentistry principles, with caries removal and no bevels. A selective etching technique was employed, and restorations were placed using a sectional matrix system.
Clinical Significance
The study provides evidence that repeated preheating of bulk fill composite is a clinically acceptable technique for dental restorations. This finding is significant because it offers clinicians a practical approach to improve the handling properties of composite materials without compromising the long-term success of the restoration. The trial was registered in (www.clinicaltrials.gov) database in 20/5/2022, with unique identification number NCT05383768.
