Cement Excess at Single Implant Crowns Malmö/Lund

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

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.

Study Overview

• Status: Completed
• Conditions: Tooth Loss; Gingivitis and Periodontal Diseases
• Intervention / Treatment: Device: implant crown

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Skåne
    • Lund, Skåne, Sweden
      • Folktandvarden Skane

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: screw-retained; 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; 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.
Active Comparator: cement-retained; 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; 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.

What is the study measuring?

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

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Determination of additional inflammatory markers - MMP8	The collected microbiological samples will additionally be analyzed for two host markers (MMP8, IL-1ß) that will be determined by ELISA.	4 times 8 weeks
Determination of additional inflammatory markers - IL-1ß	The collected microbiological samples will additionally be analyzed for two host markers (MMP8, IL-1ß) that will be determined by ELISA.	4 times 8 weeks
Radiological outcomes	A single-tooth x-ray will be obtained at the time of implant placement and again at abutment connection in order to ensure sufficient osseointegration of the implant before entering the prosthetic phase. At the time of insertion of the respective reconstruction in both groups, another periapical radiograph will be obtained to ensure the fit of the reconstruction and to check for eventual cement residue. A final x-ray will be taken at insertion of the final screw-retained implant crown to serve as baseline regarding marginal bone level at the time of final crown insertion.	12 weeks pre-BL, BL and 1year post-BL

Collaborators and Investigators

• Sponsor: University of Zurich
• Collaborators: Göteborg University; Dentsply Sirona Implants; Folktandvården Skåne AB

Study record dates

Study Major Dates

• Study Start (Actual): June 27, 2018
• Primary Completion (Actual): April 30, 2022
• Study Completion (Actual): April 30, 2022

Study Registration Dates

• First Submitted: October 11, 2018
• First Submitted That Met QC Criteria: July 8, 2019
• First Posted (Actual): July 11, 2019

Study Record Updates

• Last Update Posted (Actual): June 14, 2022
• Last Update Submitted That Met QC Criteria: June 13, 2022
• Last Verified: June 1, 2022

More Information

Terms related to this study

• Keywords: cement; implant; dental; implant prosthodontics
• Additional Relevant MeSH Terms: Infections; Stomatognathic Diseases; Mouth Diseases; Gingival Diseases; Tooth Diseases; Gingivitis; Tooth Loss; Periodontal Diseases
• Other Study ID Numbers: 2018-414

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes

IPD Plan Description

the scans of the sealed randomization envelopes will be sent to the center in Lund, Sweden whenever a patient is included and ready to take the impression.

A folder structure on switch drive is set up with the Subject numbers (1-24) in order to upload the CRFs, photographs and X rays.

• IPD Sharing Time Frame: mid 2020
• IPD Sharing Access Criteria: login provided by the study monitor (UZH)
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP); Informed Consent Form (ICF); Clinical Study Report (CSR)

Drug and device information, study documents

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