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Completed

NCT Number: NCT04015427

Cement Excess at Single Implant Crowns Malmö/Lund

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.

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Key information

Conditions

Gingivitis and Periodontal Diseases Gingival Diseases Gingivitis Infections Mouth Diseases Periodontal Diseases Stomatognathic Diseases Tooth Diseases Tooth Loss

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Folktandvården Skåne

Lund, Skåne County, Sweden

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

implant crown

Device

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.

Primary outcomes

  1. Analysis of microbiological parameters

    Time frame: Change BL to 16 weeks post-restoration

    Change relative percentage of gram-negative microorganisms

Secondary outcomes

  1. Histomorphometric analysis

    Time frame: 32 weeks after BL

    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.

  2. Immunohistologic analysis - putative periodontal pathogens

    Time frame: 32 weeks after BL

    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.

  3. Immunohistologic analysis - MMP8

    Time frame: 32 weeks after BL

    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.

  4. Immunohistologic analysis - IL1ß

    Time frame: 32 weeks after BL

    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.

  5. Analysis of inflammation markers on RNA-basis - (IL-4, IL-3, IL-1alfa, IL-1beta)

    Time frame: 32 weeks after BL

    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).

  6. Analysis of inflammation markers on RNA-basis - TNF-alfa

    Time frame: 32 weeks after BL

    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).

  7. Clinical parameters - Probing Depth

    Time frame: Every 8 weeks until 48 weeks and again at the 1-year follow-up

    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)

  8. Clinical parameters - Bleeding-on-Probing

    Time frame: Every 8 weeks until 48 weeks and again at the 1-year follow-up

    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)

  9. Clinical parameters - Plaque Index

    Time frame: Every 8 weeks until 48 weeks and again at the 1-year follow-up

    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)

Other outcomes

  1. Determination of additional inflammatory markers - MMP8

    Time frame: 4 times 8 weeks

    The collected microbiological samples will additionally be analyzed for two host markers (MMP8, IL-1ß) that will be determined by ELISA.

  2. Determination of additional inflammatory markers - IL-1ß

    Time frame: 4 times 8 weeks

    The collected microbiological samples will additionally be analyzed for two host markers (MMP8, IL-1ß) that will be determined by ELISA.

  3. Radiological outcomes

    Time frame: 12 weeks pre-BL, BL and 1year post-BL

    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.

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Collaborators

  • Dentsply Sirona Implants and Consumables
  • Folktandvården Skåne AB
  • Göteborg University

Registry information

Official study title

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

Important dates

Study start
2018
Primary completion
2022
Study completion
2022
First posted
Jul 11, 2019
Registry last updated
Jun 14, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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