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

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.

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Key information

Conditions

Class II Lesions 3D Printing Bulk Fill Composite Restorations Proximal Cavities of Posterior Teeth

Age range

22 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

3D-printed Ceramic reinforced resin restoration

Other

Tooth preparation for indirect inlay restorations follows conservative restorative principles, with the primary objective of eliminating carious tissue and unsupported enamel while preserving as much healthy tooth structure as possible. The preparation design emphasizes mechanical stability, stress distribution, and optimal seating of the final restoration. Cavity walls are shaped with a slight occlusal divergence of approximately 6-10°, facilitating proper insertion and seating of the inlay without compromising retention. The pulpal floor is prepared flat to enhance resistance form, and all internal line angles are rounded to minimize stress concentration within both the tooth and the restorative material. Cavosurface margins are ideally prepared as supragingival butt-joint margins whenever clinically feasible, promoting periodontal health, improved isolation, and easier finishing procedures.

Cuspal coverage is generally avoided in inlay preparations to maintain maximum tooth integrit

bulk fill composite

Other

For restoration of Class II cavity preparations, a sectional metal matrix system (TOR VM, Russia) will be used to properly reestablish proximal anatomy and contact. The system includes a round separation ring and a pre-contoured metal band designed to reproduce natural proximal contours. A properly sized wedge is inserted to ensure optimal gingival adaptation of the matrix band and to prevent overhangs. The cavity is thoroughly rinsed with water before proceeding with adhesive procedures.

Selective enamel etching is performed using 37% phosphoric acid gel applied to enamel margins for 15 seconds, followed by thorough rinsing and gentle air-drying. A universal adhesive system, Tetric N-Bond Universal (Ivoclar Vivadent AG), is then applied in two consecutive layers. Each layer is actively rubbed for 10 seconds, gently air-dried for 5 seconds, and light-cured for 20 seconds to ensure adequate polymerization and bond strength.

Restoration is completed using Tetric N-Ceram Bulk Fill resin c

Primary outcomes

Number of participants with a change in functional properties of the restoration using (FDI) World Dental Federation clinical criteria for the evaluation of direct and indirect restorations

Time frame: after restoration placement at 1 day (baseline), 6 months,12 months, and 18 months.

Fracture of material, retention of the restoration, marginal adaptation, occlusal wear, proximal contact utilizing visual examination and radiographic assessment.

For each criterion, one score will be chosen from 5 scores (excellent, good, satisfactory, unsatisfactory & poor).
Number of participants with a change in Biological properties of the restoration using (FDI) World Dental Federation clinical criteria for the evaluation of direct and indirect restorations

Time frame: after restoration placement at 1 day (baseline), 6 months,12 months, and 18 months.

(Postoperative hypersensitivity & tooth vitality, Recurrence of caries, erosion & abfraction,Tooth integrity (enamel cracks or tooth fractures),Periodontal response (compared to a reference tooth), Adjacent mucosa, Oral & general health) utilizing visual examination.

For each criterion, one score will be chosen from 5 scores (excellent, good, satisfactory, unsatisfactory & poor).
Number of participants with a change in Esthetic properties of the restoration using (FDI) World Dental Federation clinical criteria for the evaluation of direct and indirect restorations

Time frame: after restoration placement at 1 day (baseline), 6 months,12 months, and 18 months.

(Surface luster, Staining (surface &margin),Color match & translucency & Esthetic anatomical form) utilizing visual examination

For each criterion, one score will be chosen from 5 scores (excellent, good, satisfactory, unsatisfactory & poor).

Sponsors and collaborators

Lead sponsor

Ahmed Reda Abd EL Rahman

Other

Registry information

Official study title

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

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Feb 24, 2026
Registry last updated: Mar 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed