Cement Excess at Single Implant Crowns Malmö/Lund

Study Overview
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Brief Summary
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Abstract Aim: The primary aim of this study is to test whether or not cement residues in the submucosal environment of implants lead to a change in the microbiota and induce inflammation of the periimplant tissues. Material and Methods: 24 patients in need of a single tooth replacement will be enrolled in this cross-over controlled clinical study. All patients will receive a two-piece dental implant, which will be restored with both a cemented and a screw-retained single crown. At the time of impression taking, patients will be randomized into two groups. Patients in group A will receive a screw-retained crown. Every 8 weeks microbiological samples using sterile paper points will be collected and analyzed for bacterial content by real-time PCR. Additionally, two host markers (MMP8, IL-1ß) will be determined by ELISA. Following this first period of 16 weeks, the screw-retained crown will be replaced by a new intraorally cemented crown. Cement removal will be preformed according to best clinical procedure. These crowns will again be left for another period of 16 weeks and followed up for the harvesting of microbiological samples every 8 weeks. After the second 16-week the crowns will be removed to evaluate any excess cement. All patients will be fitted with the original screw-retained crown. Clinical parameters for inflammation and probing depths will be obtained after each 16 week-period. In group B the crowns will be incorporated in a reverse pattern. During the first 16 weeks any possible cement residues will be removed according to best clinical procedure, while for the second period of 16 weeks patients will be fitted with a screw-retained single crown. Again, microbiological and clinical parameters will be obtained at the same intervals as in Group A. After the second 16 week period the screw-retained crowns will be (re-) inserted in all patients, single tooth x-rays taken and clinical baseline values obtained. Additionally, a soft tissue biopsy will be harvested at the time of insertion of the final screw-retained crown. Patients will be followed up for another 16-week period.

Official Title
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Clinical, Microbiological and Histological Effects of Cemented Implant Restorations. A Cross-over Controlled Clinical Study

Conditions
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Gingivitis and Periodontal Diseases, Tooth Loss

Intervention / Treatment
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* Device: implant crown


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - patient older than 18 years systemically healthy subject periodontally healthy individuals absence of peri-implantitis no bone loss good oral hygiene (PCR ≤ 20%) healthy periodontal tissues (BoP≤ 20%) patients with a single tooth gap in the posterior area of either jaw (premolars and molars) at least 8mm in mandible; at least 6mm in maxilla (summers technique) Exclusion Criteria: - ongoing periodontal disease bruxism unwilling to comply with study procedures heavy smokers (≥10 cig/d) ongoing periodontitis/implantitis

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: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: screw-retained<br>Patients in group A will receive a screw-retained implant crown. Following this first period of 16 weeks, the screw-retained implant crown will be replaced by a new intraorally cemented implant crown. Cement removal will be preformed according to best clinical procedure. These implant crowns will again be left for another period of 16 weeks and followed up for the harvesting of microbiological samples every 8 weeks. After the second 16-week the implant crowns will be removed to evaluate any excess cement. All patients will be fitted with the original screw-retained implant crown. Clinical parameters for inflammation and probing depths will be obtained after each 16 week-period. | Device: implant crown<br>* After the second 16 week period the screw-retained crowns will be (re-) inserted in all patients, single tooth x-rays taken and clinical baseline values obtained. Additionally, a soft tissue biopsy will be harvested at the time of insertion of the final screw-retained crown. Patients will be followed up for another 16-week period.<br>|
| Active Comparator: cement-retained<br>In group B the implant crowns will be incorporated in a reverse pattern. During the first 16 weeks a cemented implant crown will be inserted and any possible cement residues will be removed according to best clinical procedure, while for the second period of 16 weeks patients will be fitted with a screw-retained single implant crown. Again, microbiological and clinical parameters will be obtained at the same intervals as in Group A. | Device: implant crown<br>* After the second 16 week period the screw-retained crowns will be (re-) inserted in all patients, single tooth x-rays taken and clinical baseline values obtained. Additionally, a soft tissue biopsy will be harvested at the time of insertion of the final screw-retained crown. Patients will be followed up for another 16-week period.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Analysis of microbiological parameters | Change relative percentage of gram-negative microorganisms | Change BL to 16 weeks post-restoration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Histomorphometric analysis | A soft tissue biopsy will be harvested at the time of insertion of the final screw-retained implant crown in all patients. The biopsies will be used for histomorphometric measurements. | 32 weeks after BL | 
| Immunohistologic analysis - putative periodontal pathogens | The biopsies will be used for the determination of inflammation and infection markers applying light-microscopy. Gingival crevicular fluid (GCF) will be collected using standardized filter paper strips. A battery of 10 putative periodontal pathogens will be analyzed using real-time PCR. | 32 weeks after BL | 
| Immunohistologic analysis - MMP8 | The biopsies will be used for the determination of inflammation and infection markers applying light-microscopy. Gingival crevicular fluid (GCF) will be collected using standardized filter paper strips. | 32 weeks after BL | 
| Immunohistologic analysis - IL1ß | The biopsies will be used for the determination of inflammation and infection markers applying light-microscopy. Gingival crevicular fluid (GCF) will be collected using standardized filter paper strips. | 32 weeks after BL | 
| Analysis of inflammation markers on RNA-basis - (IL-4, IL-3, IL-1alfa, IL-1beta) | Tissue samples will further be processed with a (ribonucleic acid) RNA solution to allow for RNA extraction. This will then be analyzed via polymerase chain reaction (PCR) to determine expression patterns of markers such as Interleukin (IL-4, IL-3, IL-1alfa, IL-1beta) and tumor necrose factor (TNF-alfa). | 32 weeks after BL | 
| Analysis of inflammation markers on RNA-basis - TNF-alfa | Tissue samples will further be processed with a (ribonucleic acid) RNA solution to allow for RNA extraction. This will then be analyzed via polymerase chain reaction (PCR) to determine expression patterns of markers such as Interleukin (IL-4, IL-3, IL-1alfa, IL-1beta) and tumor necrose factor (TNF-alfa). | 32 weeks after BL | 
| Clinical parameters - Probing Depth | In order to assess the inflammatory status of the peri-implant tissue, different parameters will be assessed: 1) plaque index (dichotomous values) 2) keratinized tissue width (continuous) 3) BOP (dichotomous), 4) PD (continuous), 5) recession (continuous) | Every 8 weeks until 48 weeks and again at the 1-year follow-up | 
| Clinical parameters - Bleeding-on-Probing | In order to assess the inflammatory status of the peri-implant tissue, different parameters will be assessed: 1) plaque index (dichotomous values) 2) keratinized tissue width (continuous) 3) BOP (dichotomous), 4) PD (continuous), 5) recession (continuous) | Every 8 weeks until 48 weeks and again at the 1-year follow-up | 
| Clinical parameters - Plaque Index | In order to assess the inflammatory status of the peri-implant tissue, different parameters will be assessed: 1) plaque index (dichotomous values) 2) keratinized tissue width (continuous) 3) BOP (dichotomous), 4) PD (continuous), 5) recession (continuous) | Every 8 weeks until 48 weeks and again at the 1-year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cement, dental, implant, implant prosthodontics