Effect of Different Cavity Designs on the Clinical Performance of 3D- Printed Resin Composite Partial-Coverage Restorations in Vital Molars

Effect of Different Cavity Designs on the Clinical Performance of 3D- Printed Resin Composite Partial-Coverage Restorations in Vital Molars With Complex Cavities: An 18 Month Randomized Clinical Trial

This randomized clinical trial aims to evaluate the effect of different cavity designs on the clinical performance of 3D-printed resin composite partial-coverage restorations in vital molars with complex cavities over an 18-month follow-up period.

Study Overview

• Status: Not yet recruiting
• Conditions: Clinical Performance
• Intervention / Treatment: Procedure: Anatomical cavity design preparation; Procedure: Butt joint cavity design preparation

Detailed Description

Despite these material advancements, growing evidence indicates that cavity preparation design exerts a greater influence on the clinical performance of indirect restorations than material selection alone. However, current evidence regarding preparation design is predominantly derived from in vitro studies and remains inadequately validated under clinical conditions, particularly in vital molars. Although recent randomized clinical trials have begun to address this gap, available data remain limited and largely confined to endodontically treated teeth. Therefore, a rigorously designed randomized clinical trial is warranted to evaluate the influence of different cavity preparation designs on the clinical performance of indirect restorations in vital molars.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adult patients aging 20-45 years.
2. Healthy males and females
3. Patients with good oral hygiene
4. Patients presenting with at least one eligible permanent molar requiring a partial-coverage restoration.
5. Patients willing and able to attend scheduled follow-up visits for 18 months.
6. Permanent maxillary or mandibular molars.
7. Vital teeth with a positive response to cold thermal testing.
8. Complex Large or severely compromised cavities resulting from primary or secondary caries (ICDAS 5 or 6) and/or replacement of large defective restorations with at least 2 missing cavity walls requiring overlay restorations
9. Well-formed and fully erupted in normal functional occlusion with natural antagonist and adjacent teeth.
10. Absence of any radiographic, periodontal or periapical changes.

Exclusion Criteria:

1. Participants with general/systemic illness.
2. Pregnant or lactating females.
3. Concomitant participation in another research study.
4. Inability or unwillingness to comply with study visits and procedures.
5. Heavy bruxism or other parafunctional habits
6. Known allergic reactions against any components of the used materials
7. Patients receiving orthodontic treatment.
8. Poor oral hygiene or high caries activity.
9. Non vital teeth.
10. Hypersensitive teeth.
11. Teeth with prior endodontic treatment.
12. Teeth with spontaneous pain or signs/symptoms of irreversible pulpitis.
13. Teeth with advanced periodontal disease or mobility.
14. Teeth with a history of direct or indirect pulp capping procedure.
15. Teeth with vertical root fractures or cracked tooth syndrome

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Anatomical cavity design preparation; Following caries excavation and removal of defective restorations, cavity preparations will be carried out according to the accepted principles of adhesive overlays. The cavity walls will be prepared with 6-12° internal axial wall divergence using blue-coded tapered round-end diamond burs (Komet, USA) and subsequently finished using extra-fine yellow-coded tapered round-end diamond burs (#368EF, Komet, USA). The thickness of potentially maintainable cusps will be assessed using a dental caliper (Diamonds Surgical Instruments, Pakistan). Weakened or undermined cusps (less than 2 mm thickness) will be reduced using the same diamond burs to create an anatomical occlusal reduction following the natural tooth morphology, with a reduction of 2 mm.	Procedure: Anatomical cavity design preparation; Cavity preparation design for adhesive restoration
Active Comparator: Butt joint cavity design preparation; The cavity walls will be prepared with 6-12° internal axial wall divergence using blue-coded tapered round-end diamond burs (Komet, USA) and subsequently finished using extra-fine yellow-coded tapered round-end diamond burs (#368EF, Komet, USA). The thickness of potentially maintainable cusps will be assessed using a dental caliper (Diamonds Surgical Instruments, Pakistan). The occlusal reduction design, where weakened or undermined cusps will be reduced using a wheel stone (#909, Komet, USA) to create a flat butt-joint occlusal design with a uniform occlusal reduction of 2 mm. Additional reduction will be performed when necessary, and the available interocclusal clearance will be verified using a graduated periodontal probe in maximum intercuspation and eccentric movements.	Procedure: Butt joint cavity design preparation; Cavity preparation design for adhesive restoration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fracture	Modified USPHS Ryge Criteria (Ordinal scoring system)	18 Months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retention, marginal integrity, marginal discoloration, wear/anatomic form, secondary caries and surface texture	Modified USPHS Ryge Criteria (Ordinal scoring system)	18 Months

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: June 19, 2026
• First Submitted That Met QC Criteria: June 19, 2026
• First Posted (Actual): June 25, 2026

Study Record Updates

• Last Update Posted (Actual): June 25, 2026
• Last Update Submitted That Met QC Criteria: June 19, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: Effect of Cavity Designs

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No