The Role of a New Prosthodontics Device in Hard and Soft Tissue Changes After Subcrestal Implant Placement

Study Overview
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Brief Summary
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The present randomized controlled trial aims to assess the influence of a new prosthodontics device (Gingival Former Abutment -GFA) on peri-implant bone loss and soft tissue changes and health after subcrestal oral implant placement. The participants will be divided in two groups and receive either crestal implant placement and traditional healing abutment or subcrestal implant placement and GFA. Clinical and radiographic examination will be performed at implant placement surgery, prosthetic load, 6 and 12 months follow-up.

Detailed Description
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According to current literature, physiological bone loss around oral implants is expected after placement and load (1 mm during the first year and 0.2 mm each subsequent year). Different implant designs and surgical protocols have been tested to minimize bone resorption, and subcrestal implant placement partially seems to overcome this issue. However, if this procedure increases the length of the transmucosal tunnel, increasing the risk of peri-implant soft tissue infection. The GFA was created to limit both the loss of peri-implant crestal bone and the extension of the transmucosal tunnel. The GFA follows the one abutment one time concept, which is believed to limit disturbances of the peri-implant hard and soft tissues healing due to the removal of the traditional healing abutments during prosthetic load procedures. Our objective is to validate or deny this claim. The study is a monocentric, pragmatic, single-blinded, randomized clinical trial (RCT) of parallel design. The trial will have a one-year duration, with data collection at the surgical phase, at implant load and 6 and 12 months after load. The primary outcome will be radiographical MBL (marginal bone level) changes around the implant. Secondary outcomes will be the assessment of the peri-implant soft tissues.

Official Title
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The Role of a New Prosthodontics Device in Hard and Soft Tissue Changes After Subcrestal Implant Placement: 12-months, Parallel, Randomized Clinical Trial

Conditions
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Edentulous Alveolar Ridge

Intervention / Treatment
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* Device: Gingival Former Abutment
* Procedure: Subcrestal Implant
* Device: Healing Abutment
* Device: Prosthetic Crown
* Procedure: Crestal Implant


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ability to comprehend and sign informed consent. Male and female subjects, aged 18-75 years, inclusive. Good general health (free of systemic diseases such as diabetes, HIV infection or genetic disorder, ongoing malignant disease of any type that could influence the outcome of the treatment and might interfere with the evaluation of the study objectives). Good oral health (no decay, periapical or periodontal lesions, PI and BOP <25%). Patient with posterior single missing tooth: for at least 5 months, mandibular or maxillary, intercalated (distance between teeth more than 7.5 mm), at least 11 mm of height residual bone (from bone crest to maxillary sinus or inferior alveolar nerve), at least 5 mm of bone width (buccal - palatal/lingual). Availability for the 12-month duration of the study. Exclusion Criteria: Not willing to follow the agreed protocol. Presence of orthodontic appliances. Smokers more than 10 cigarettes per day. Chronic obstructive pulmonary disease and asthma. Tumors or significant pathology of the soft or hard tissues of the oral cavity. Current radiotherapy or chemotherapy. Pregnant or lactating women. Parafunctions like bruxism. Previous interventions to increase bone thickness in the implant area. Current or past assumption of medications that may influence surgical therapy and/or interfere with healing following surgical treatment. Systemic diseases that constitute a contraindication to surgical therapy and/or interfere with healing following surgical treatment.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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
Interventional Model Description: Monocentric, single blinded, randomized clinical trial, parallel design.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Subcrestal implant and gingival former abutment (GFA)<br>The subjects receive a subcrestal implant and a prosthodontic device (GFA) immediately during the surgery. The GFA will not be removed upon prosthetic load. It will be an integral part of the prosthetic finalization. | Device: Gingival Former Abutment<br>* GFA is positioned on the sub-crestal implant during the surgery and it is no longer removed. This follows the one abutment one time concept and should prevent bone loss and transmucosal tunnel.<br>Procedure: Subcrestal Implant<br>* Placement of the endosseous sub-crestal dental implant through dedicated drills with 35 Newton insertion torque. It is positioned 2 mm under the crestal bone.<br>Device: Prosthetic Crown<br>* A zirconia prosthetic crown finalizes the implant rehabilitation.<br>|
| Active Comparator: Crestal implant and traditional abutment<br>The subjects receive a crestal implant and healing abutment. The healing abutment will be replaced by a definitive abutment to the prosthetic load. | Device: Healing Abutment<br>* A healing abutment is positioned on crestal implant during surgery. It is removed at prosthetic finalization.<br>Device: Prosthetic Crown<br>* A zirconia prosthetic crown finalizes the implant rehabilitation.<br>Procedure: Crestal Implant<br>* Placement of the endosseous crestal implant through dedicated drills with 35 Newton insertion torque at level of the alveolar bone.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Marginal Bone Level (MBL) | The reabsorption of the bone measured through radiographically change on standardised radiographs. Baseline values will be compared to the values recorded in the follow-up visits. | Surgery, 3, 9 and 15 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in PD (periodontal depth) (implant site) | Change in periodontal depth value (from the gingival margin to the bottom of the pocket). Baseline values will be compared to the values recorded in the follow-up visits. | 3, 9 and 15 months | 
| Change in REC (Clinical Gingival Recession) (implant site) | Change in recession value should be calculated. Baseline values will be compared to the values recorded in the follow-up visits. | 3, 9 and 15 months | 
| Change in BOP (Bleeding on Probing) (implant site) | Change in percentage of sites positive to bleeding on probing (4 point each situ). Baseline values will be compared to the values recorded in the follow-up visits. | 3, 9 and 15 months | 
| Change in PI (Plaque Index) (implant site) | Change in percentage of site with plaque (4 point each situ). Baseline values will be compared to the values recorded in the follow-up visits. | 3, 9 and 15 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Oral Implants, Abutment, Subcrestal