Clinical Evaluation of Monolithic Zirconia Crowns

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Clinical Evaluation of Monolithic Zirconia and Metal-ceramic Posterior Crowns

Conditions
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Dental Materials

Intervention / Treatment
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* Procedure: Monolithic zirconia
* Procedure: Metal-ceramic


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

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

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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monolithic zirconia, crowns, metal-ceramic, clinical evaluation, survival, wear