To clinically evaluate the performance of preheated versus non-preheated short fiber-reinforced composite (SFRC) restorations in Class I posterior cavities over a 12-month period

Resin-based composites are widely used for posterior restorations due to their aesthetic properties and adhesive capabilities. However, polymerization shrinkage stress and insufficient fracture resistance remain major concerns in stress-bearing areas.

Short fiber-reinforced composites (SFRCs) were developed to improve mechanical properties and crack-stopping ability. everX Posterior (GC Corporation, Tokyo, Japan) contains randomly oriented E-glass fibers within a resin matrix, enhancing fracture toughness and load-bearing capacity.

Preheating composite materials has been proposed to reduce viscosity, improve flow, enhance cavity adaptation, and potentially increase the degree of conversion. Elevated temperature reduces internal friction among monomers, thereby improving polymerization kinetics. Despite promising laboratory findings, limited clinical evidence exists regarding the impact of preheating on SFRC performance.

Therefore, this randomized clinical trial aimed to evaluate the clinical behavior of SFRC restorations placed with and without preheating in Class I cavities over 12 months

Inclusion Criteria:

• Presence of bilateral Class I carious lesions in posterior teeth requiring restorative treatment
• Teeth with vital pulps and no signs of irreversible pulpitis
• Good general health

Exclusion Criteria:

• Patients with poor oral hygiene or high caries risk
• Presence of parafunctional habits (e.g., bruxism)
• Patients with systemic diseases affecting oral health or salivary flow