This in-vivo study investigates early (48h), mature (2 weeks) and long-term (3 months) biofilm formation and composition on temporary push-on cones (exchangeable conical rings) made of noble-alloy-based materials (Pagalinor, PA) in comparison to Titanium-6Aluminum-7Niobium alloy (TAN) presently used in the transmucosal portion of dental implant abutments.
Oral biofilm (dental plaque) consists of bacteria and their metabolic products as well as saliva components and food residues. It is recognizable as a tough and structured coating on teeth and artificial surfaces within the oral cavity. Plaque development is a physiological process that begins immediately after cleaning of the oral surface. If the biofilm is not removed by daily oral hygiene, it continues to mature while changing the structure and its microbial composition. Implant restorations comprise the osseous implant portion predominantly manufactured from titanium alloys, the transmucosal implant portion (in most implant systems as a separate abutment), and the clinical crown, which is in most systems extraorally cemented on an abutment and screw-retained onto the implant. According to current knowledge, microbial colonization of the implant abutment surface plays a significant role in the aetiology of peri-implantitis. This study investigates the antibacterial potential of a temporary push-on cone (conical ring) that could reduce the risk of bacterial related peri-implant diseases due to decreased biofilm susceptibility, compared to current available transmucosal materials, in the short- and long-run. The test material Pagalinor®2 (PA) is an established material in dental medicine and has proven to accumulate least biofilm in an in-vivo biofilm sampling model using removable splints. The control material consists of the current transmucosal implant abutment material Titanium-6Aluminum- 7Niobium alloy (TAN). The push-on rings are designed for repeated application along the transmucosal implant abutment portion with high precision fit and will allow biofilm sampling in the natural implant environment. Profound insight into the native homeostasis of biofilm formation will be obtained and therefore enhance the knowledge about long-term tissue response.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Rings made of PA (test) 0.2mm in thickness are pushed on the conical titanium base (abutment) of implant crowns and are removed and replaced after 48h, 2 weeks and 3 months for quantification of the bacterial biofilm. Test rings are applied in a split-mouth design provided that 2 implants are present (total of 4 months study period), or one after the other when only 1 implant is present (total of 8 months study period).
Rings made of TAN (control) 0.2mm in thickness are pushed on the conical titanium base (abutment) of implant crowns and are removed and replaced after 48h, 2 weeks and 3 months for quantification of the bacterial biofilm. Control rings are applied in a split-mouth design provided that 2 implants are present (total of 4 months study period), or one after the other when only 1 implant is present (total of 8 months study period).
UZB (University Center for Dental Medicine Basel)
Basel, Switzerland
RECRUITINGChange in total bacterial load formed on the removable rings of each material
Quantification of the bacterial load formed on the removable rings of each material by quantitative real-time PCR (qPCR) using primers specific to highly conserved regions of bacterial 16S rRNA genes.
Time frame: at 48 hours after ring placement, 2 weeks after ring placement and 3 months after ring placement
Change in bacterial composition (taxonomic diversity) between different materials at various time points by using metagenomic sequencing analysis
To assess differences in bacterial composition (taxonomic diversity) between different materials at various time points by Illumina MiSeq sequencing. The taxonomy of each 16S rRNA gene sequence will be analyzed by Ribosomal Database Project (RDP) Classifier (http://rdp.cme.msu.edu/) against the SILVA (SSU123) 16S rRNA database using a confidence threshold of 70%.
Time frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in probing pocket depth (PPD) in mm
Change in probing pocket depth (PPD) to investigate the inflammatory tissue response
Time frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in bleeding on probing (BoP)
Recording bleeding on probing (BoP) to investigate the inflammatory tissue response
Time frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
Change in noninvasive laser doppler flowmetry
Change in noninvasive laser doppler flowmetry to to measure the blood flow of mucosa next to the ring
Time frame: at baseline, 2 weeks after ring placement and 10 weeks after ring placement
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Masking
DOUBLE
Enrollment
33
Change in the cells of the peri-implant soft tissue
To investigate the attachment of peri-implant soft tissues to implant materials, fibroblasts and junctional epithelial cells markers will be analysed using real-time quantitative PCR (RT-qPCR).
Time frame: at 2 weeks after ring placement