Clinical Evaluation of Monolithic Zirconia Crowns

Clinical Evaluation of Monolithic Zirconia and Metal-ceramic Posterior Crowns

The objectives of the present study are to compare the survival rates and possible biological and technical complications of metal-ceramic, and monolithic third-generation zirconia posterior crowns. The null hypothesis is that no differences would be found between the parameters studied for each type of restoration.

Study Overview

• Status: Active, not recruiting
• Conditions: Dental Materials
• Intervention / Treatment: Procedure: Monolithic zirconia; Procedure: Metal-ceramic

Detailed Description

Seventy patients requiring at least one crown in the posterior region of the maxilla or mandible were included in this study. All subjects were recruited from the Master in Buccofacial Prostheses and Occlusion (Faculty of Odontology, University Complutense of Madrid, Spain). Before treatment, patients were informed of the study objectives, clinical procedures, materials used, advantages and possible risks of the ceramic material, and other therapeutic alternatives. Prior to the study, participants were asked to provide written informed consent. Seventy posterior crowns were produced and allocated in parallel and randomly to either monolithic third-generation zirconia, or metal-ceramic (MC) restorations. The clinical procedures were performed by two experienced clinicians. All participants received oral hygiene instructions and a professional tooth cleaning prior to prosthetic treatment. The abutment teeth were prepared with a 0.8- to 1-mm-wide circumferential chamfer, an axial reduction of 1 mm and an occlusal reduction of 1- to 2.0-mm. A 10- to 15- degree angle of convergence was achieved for the axial walls. Tooth preparations were scanned with an intraoral scanner and the crowns were designed using specific software. The restorations were then cemented using a resin self-adhesive cement. After cementation, occlusal contacts were evaluated, and the adjusted surfaces were polished using a porcelain polishing kit. The 70 crowns were examined at 1week (baseline),1, 2 and 3 years by 2 researchers who were not involved in the restorative treatment.

• Study Type: Interventional
• Enrollment (Anticipated): 70
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Madrid, Spain, 28040
    • Faculty of Odontology

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• One posterior tooth (molar or premolar) to be crowned
• Vital abutment or abutment with an adequate endodontic treatment
• Abutment not crowned previously
• Periodontally healthy abutment with no signs of bone resorption or periapical disease.
• Adequate occlusogingival height ≥ 4 mm.
• Stable occlusion and the presence of natural antagonist tooth.

Exclusion Criteria:

• Patients who present reduced crown length (less than 4 mm occlusogingival height).
• Poor oral hygiene, high caries activity, or active periodontal disease

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Monolithic zirconia; To assess the clinical performance and survival of posterior monolithic zirconia crowns	Procedure: Monolithic zirconia; posterior crowns; Other Names: Katana
Active Comparator: Metal-ceramic; To assess the clinical performance and survival of posterior metal-ceramic crowns	Procedure: Metal-ceramic; posterior crowns

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quality of restorations at baseline	The quality of the surface and color, anatomical form and marginal integrity was assessed using the California Dental Association's (CDA) assessment system. Each CDA criterion was ranked on a scale of 1 to 4, where 4 = excellent, 3 = good, 2 = unacceptable (repair), and 1 = unacceptable (replacement).	Baseline
Quality of restorations at 1 year	The quality of the surface and color, anatomical form and marginal integrity was assessed using the California Dental Association's (CDA) assessment system. Each CDA criterion was ranked on a scale of 1 to 4, where 4 = excellent, 3 = good, 2 = unacceptable (repair), and 1 = unacceptable (replacement).	1 year
Quality of restorations at 2 years	The quality of the surface and color, anatomical form and marginal integrity was assessed using the California Dental Association's (CDA) assessment system. Each CDA criterion was ranked on a scale of 1 to 4, where 4 = excellent, 3 = good, 2 = unacceptable (repair), and 1 = unacceptable (replacement).	2 years
Quality of restorations at 3 years	The quality of the surface and color, anatomical form and marginal integrity was assessed using the California Dental Association's (CDA) assessment system. Each CDA criterion was ranked on a scale of 1 to 4, where 4 = excellent, 3 = good, 2 = unacceptable (repair), and 1 = unacceptable (replacement).	3 years
Plaque Index (PI) at baseline	Plaque Index (PI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	baseline
Plaque Index (PI) at 1 year	Plaque Index (PI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	1 year
Plaque Index (PI) at 2 years	Plaque Index (PI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	2 years
Plaque Index (PI) at 3 years	Plaque Index (PI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	3 years
Gingival Index (GI) at baseline	Gingival Index (GI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	Baseline
Gingival Index (GI) at 1 year	Gingival Index (GI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	1 year
Gingival Index (GI) at 2 years	Gingival Index (GI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	2 years
Gingival Index (GI) at 3 years	Gingival Index (GI) of the abutment and control teeth. A score of 0 to 3 was assigned. Higher score means a worse outcome.	3 years
Margin stability at baseline	To assess the gingival margin stability throughout the evaluation period (subgingival, isogingival or supragingival)	Baseline
Margin stability at 1 year	To assess the gingival margin stability throughout the evaluation period (subgingival, isogingival or supragingival)	1 year
Margin stability at 2 years	To assess the gingival margin stability throughout the evaluation period (subgingival, isogingival or supragingival)	2 years
Margin stability at 3 years	To assess the gingival margin stability throughout the evaluation period (subgingival, isogingival or supragingival)	3 years
Probing depth at baseline	Probing depth of the abutment and control teeth. A score of 0 to 4 was assigned. Higher score means a worse outcome	Baseline
Probing depth at 1 year	Probing depth of the abutment and control teeth. A score of 0 to 4 was assigned. Higher score means a worse outcome	1 year
Probing depth at 2 years	Probing depth of the abutment and control teeth. A score of 0 to 4 was assigned. Higher score means a worse outcome	2 years
Probing depth at 3 years	Probing depth of the abutment and control teeth. A score of 0 to 4 was assigned. Higher score means a worse outcome	3 years
Patient satisfaction at 3 years	Subjective patient satisfaction using Visual analogue scale (VAS) ranged from 0 (worst possible result) to10 (best possible result). The items analyzed were: esthetics, function, comfort, overall satisfaction	3 years

Collaborators and Investigators

• Sponsor: Universidad Complutense de Madrid
• Collaborators: Kuraray Co. Ltd
• Investigators: Study Director: MARIA J SUAREZ, PhD, Universidad Complutense de Madrid

Study record dates

Study Major Dates

• Study Start (Actual): May 6, 2019
• Primary Completion (Actual): December 15, 2020
• Study Completion (Anticipated): July 15, 2023

Study Registration Dates

• First Submitted: June 23, 2021
• First Submitted That Met QC Criteria: June 23, 2021
• First Posted (Actual): June 29, 2021

Study Record Updates

• Last Update Posted (Estimate): January 24, 2023
• Last Update Submitted That Met QC Criteria: January 22, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Keywords: survival; wear; crowns; clinical evaluation; monolithic zirconia; metal-ceramic
• Other Study ID Numbers: University Complutense Madrid; 4157246 (Other Grant/Funding Number: Kuraray Europe GmbH)

Drug and device information, study documents

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