Vital and Non-vital Posterior Teeth Restored With Onlays and Single Crowns Using Three Different Restorative Materials.

Longterm Outcomes of Vital and Non-vital Posterior Teeth Restored With Onlays and Single Crowns: a Randomized, Controlled, Clinical Trial

The objective of this study is to assess the survival rate and the biological and technical outcomes of onlays and single crowns made out of different restorative materials on vital and non-vital teeth. The onlays are made either out of a lithium-disilicate glass ceramic (E.max CAD, Ivoclar Vivadent), hybrid ceramic (VITA ENAMIC, VITA Zahnfabrik) or out of a lithium aluminosilicate glass ceramic reinforced with lithium disilicate (N!ce, Straumann). The crowns are made either out of lithium aluminosilicate glass ceramic reinforced with lithium disilicate (N!ce, Straumann), hybrid ceramic (VITA ENAMIC, VITA Zahnfabrik) or lithium-disilicate glass ceramic (E.max CAD, Ivoclar Vivadent).

Study Overview

• Status: Completed
• Conditions: Decayed Teeth
• Intervention / Treatment: Procedure: Crown preparation; Procedure: Onlay preparation

• Study Type: Interventional
• Enrollment (Actual): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Canton of Geneva
    • Geneva, Canton of Geneva, Switzerland, 1204
      • University of Geneva

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• • Subjects with the need for a fixed reconstruction in premolar and molar region with indication for either crown or onlay.

  • min. 18 years of age and ≤ 80 years
  • Patient with physical status PS1 and PS2 (according to Physical Status Classification System of the American Society of Anesthesiologists; Attachment 5)
  • Capable of providing written informed consent
  • Absence of any active periodontal and pulpal disease

Exclusion Criteria:

• Presence of conditions requiring chronic routine prophylactic use of antibiotics or prolonged use of steroids e.g. history of rheumatic heart disease, bacterial endocarditis, cardiac vascular anomalies, prosthetic joint replacements, etc.
• Patients with history of renal failure, bleeding disorders, metabolic bone disorder, uncontrolled endocrine disorders, HIV infection, Hepatitis
• History of neoplastic disease requiring the use of radiation or chemotherapy
• Inability to perform adequate oral hygiene
• Significant reduced saliva flow rate
• Unable or unwilling to cooperate for the trial period
• Allergy to any components of the reconstruction materials and cements
• Alcohol or drug abuse
• Pregnant or lactating women

Specific criteria:

• Root caries / root canal caries
• Extreme short dental arch (eSDA)
• Severe bruxism or clenching habits

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Crown restoration; The tooth is restored with a conventional, full-coverage crown.	Procedure: Crown preparation; The conventional crown preparation will be performed.
Experimental: Onlay restoration; The tooth is restored with a defect-oriented onlay.	Procedure: Onlay preparation; A defect-oriented tooth preparation is performed for an onlay restoration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Restoration survival	Survival of the inserted restorations	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fractures of the restorations.	Any chipping (uncritical fractures) or critical fractures will be assessed.	5 years
Tooth vitality	The presence or absence of tooth vitality will be assessed by means of vitality test using cold spray.	5 years
Biological outcome - presence of secondary caries	Biological outcome - presence of secondary caries - of the treated teeth using magnification loops, a dental probe and radiographs.	5 years
Biological outcome - Bleeding on Probing	Bleeding on probing measures of the treated tooth using a periodontal probe.	5 years
Biological outcome - Plaque index	Assessment of the Plaque index of the treated tooth using a dental probe.	5 years
Biological outcome - tooth fractures	Assessment of tooth /root fractures using a dental probe and magnification loops.	5 years
Biological outcome - pocket probing depth	The pocket probing depth will be assessed in millimeters with a periodontal probe with 1mm distances.	5 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Restoration wear	Wear of the restorations by measuring the surface changes of the restorations over time. This is analyzed by means of digital intraoral scanning at different time points and measured in micrometers.	5 years

Collaborators and Investigators

• Sponsor: Dr. med. dent. Malin Strasding
• Collaborators: Institut Straumann AG; Ivoclar Vivadent AG

Study record dates

Study Major Dates

• Study Start (Actual): March 4, 2019
• Primary Completion (Actual): February 6, 2024
• Study Completion (Actual): February 6, 2024

Study Registration Dates

• First Submitted: December 19, 2024
• First Submitted That Met QC Criteria: November 20, 2025
• First Posted (Actual): December 2, 2025

Study Record Updates

• Last Update Posted (Actual): December 2, 2025
• Last Update Submitted That Met QC Criteria: November 20, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: crown; full coverage; onlay; partial coverage; ceramic restoration
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Tooth Demineralization; Dental Caries
• Other Study ID Numbers: GTC Study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: because of private patient data .

Drug and device information, study documents

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