Performance of Reinforced 3D-Printed Versus Direct Bulk-Filled Resin Composites for Restoring Extensive Class II Cavities in Vital Molars

Performance of Reinforced 3D-Printed Versus Direct Bulk-Filled Resin Composites for Restoring Extensive Class II Cavities in Vital Molars: A Randomized Clinical Trial

Most published research on 3D-printed restorative materials is laboratory-based, focusing primarily on mechanical performance and material properties under controlled conditions. While such studies provide important foundational data, they do not fully replicate the complexity of the oral environment. Only a limited number of clinical investigations have directly compared 3D-printed restorations with conventional direct composite restorations in Class II cavities Furthermore, the integration of a digital workflow introduces additional costs and time requirements related to equipment, software, and training. These factors must be justified by demonstrable improvements in clinical outcomes or cost-effectiveness. By evaluating both clinical performance and economic impact, this trial aims to generate practical, real-world evidence that can guide clinicians in selecting appropriate restorative materials and techniques for routine dental practice.

Inclusion Criteria:

Patient-related:

• Adults aged 22 to 45 years.
• Low to moderate caries risk.
• Normal occlusion.
• No signs or symptoms of temporomandibular joint disorders.
• Satisfactory oral hygiene.
• Medically fit to receive routine restorative dental treatment.

Lesion-related:

• Permanent molar requiring a compound Class II restoration.
• Primary carious lesion classified as ICDAS score 5.
• Presence of an adjacent tooth and a sound opposing tooth in occlusion.
• No clinical signs or symptoms of irreversible pulpitis in the involved, adjacent, or opposing teeth.
• No radiographic evidence of periapical pathology.

Exclusion Criteria:

Patient-related:

• Bruxism.
• Poor cooperation.
• Inability or unwillingness to attend follow-up visits.
• Anticipated travel during the study period.
• Poor oral hygiene.
• Chronic or advanced periodontitis.
• Known allergy to any study materials.
• Pregnant or breastfeeding women.

Lesion-related:

• Teeth with visible fractures or cracks.
• Rampant caries.
• Defective restorations on adjacent or opposing teeth.
• Atypical extrinsic staining that may interfere with evaluation.
• Radiographic signs of apical pathology.