Influence of Abutment Shape on Peri-implant Marginal Bone Loss

Study Overview
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Brief Summary
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A study designed as a randomized controlled trial of parallel group design will be conducted at the Dental clinic of the University of Valencia to evaluate the influence of 2.5 mm high abutments with different shapes (commercially available high abutments vs high abutments with modified shape to imitate short abutments) on peri-implant bone loss around bone level implants with platform switching in partially edentulous patients that require a fixed rehabilitation supported by two implants in the posterior mandible or maxilla and in fixed rehabilitation supported by one implant in the anterior mandible or maxilla.

Detailed Description
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A study designed as a randomized controlled trial of parallel group design will be conducted at the Dental clinic of the University of Valencia to evaluate the influence of 2.5 mm high abutments with different shapes (commercially available high abutments vs high abutments with modified shape to imitate short abutments) on peri-implant bone loss around bone level implants with platform switching in partially edentulous patients that require a fixed rehabilitation supported by two implants in the posterior mandible or maxilla and in fixed rehabilitation supported by one implant in the anterior mandible or maxilla (from premolar to premolar).

Official Title
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Influence of Different Abutment Shape on Peri-implant Marginal Bone Loss: A Randomized Clinical Trial.

Conditions
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Dental Implant, Bone Resorption

Intervention / Treatment
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* Procedure: Commercially available high abutments placement
* Procedure: Modified shape abutments


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Any subject requiring two implants in the posterior mandible or maxilla, being at least 18 years old and able to sign an informed consent. Final patient inclusion will be made after flap elevation during the implant placement surgery to be able to confirm the presence of a vertical thickness ≥ 3mm of keratinized soft tissues. Bone volumes should allow the placement of implants at least 8 mm long (i.e, 10 mm bone height to the inferior alveolar nerve) and 4.2 mm wide (7 mm wide bone crest) without bone regeneration procedures. Patients will be grouped into: 1) non smokers; 2) light smokers (≤ 10 cigarettes/day); 3) heavy smokers (≥ 11 cigarettes/day) Exclusion Criteria: Patients unable to commit to follow-up. General contraindications to implant surgery. Immuno-suppressed/immune-compromised patients. Patients irradiated in the head and/or neck. Uncontrolled diabetes. Pregnancy or lactation. Untreated periodontal disease. Poor oral hygiene and motivation. Addiction to alcohol or drugs. Psychiatric problems and/or unrealistic expectations. Patients with an acute infection (abscess) or suppuration in the site intended for implant placement. Patients treated or under treatment with intravenous amino-bisphosphonates. Patients referred only for implant placement if the follow-up cannot be done at the treatment center. Patients participating in other studies, if the present protocol could not be fully adhered to.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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 |
| --- | --- |
| Active Comparator: Control group - Commercially available high abutments<br>Commercially available 2.5mm high abutments | Procedure: Commercially available high abutments placement<br>* Patients will be randomly selected for the commercially available high abutments option. Two or three implants will be placed following the drilling protocol suggested by the manufacturer. Implants will be placed 0.5mm subcrestal. Once the implants have been placed, periapical radiographs and clinical pictures will be taken. Implants will be uncovered 10 weeks after being placed. After performing the incision and elevation a minimal flap, conventional high transmucosal abutments will be screwed using the torque recommended by the manufacturer. Once the abutments have been screwed, periapical radiographs and clinical pictures will be taken. The abutments will not be unscrewed thereafter throughout the study.<br>|
| Experimental: Test group - Modified shape abutments<br>Modified shape 2.5mm high abutments (imitating the shape of 0.5mm short abutments) | Procedure: Modified shape abutments<br>* Patients will be randomly selected for the modified shape abutments option. Two or three implants will be placed following the drilling protocol suggested by the manufacturer. Implants will be placed 0.5mm subcrestal. Once the implants have been placed, periapical radiographs and clinical pictures will be taken. Implants will be uncovered 10 weeks after being placed. After performing the incision and elevation a minimal flap, modified high transmucosal abutments will be screwed using the torque recommended by the manufacturer. Once the abutments have been screwed, periapical radiographs and clinical pictures will be taken. The abutments will not be unscrewed thereafter throughout the study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peri-implant bone level changes | Assessed on digital periapical radiographs taken with the paralleling technique at delivery of crowns (implant loading) and 12 months afterwards. | 12 months after implant loading | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant survival rate | % of implants in function | 12 months after implant loading | 
| Probing pocket depth | Measured in millimeters with a millimetered periodontal probe | 12 months after implant loading | 
| Bleeding on probing | Positive or negative bleeding after having probed with a millimetered periodontal probe | 12 months after implant loading | 
| Peri-implant soft tissue recession | Measured in millimeters with a millimetered periodontal probe | 12 months after implant loading |