Investigation of Biofilm Formation on Temporary push-on Rings of Implant Crowns

Temporary push-on Rings of Antimicrobial Alloys for Transmucosal Implant Abutment Systems: a Randomized Clinical Study on Early and Mature Biofilm Formation

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.

Inclusion Criteria:

• Informed Consent signed by the subject
• Presence of one or more bone level titanium implant prior to insertion of the final restoration
• No systemic illness
• No heavy smoking (smoking <10 cigarettes/day)
• No pregnancy
• No active periodontitis (probing pocket depth ≤4 mm)
• No pharmacological treatment or antibiotic therapy during or up to three months before the study

Exclusion Criteria:

• Systemic illness (e.g. Diabetes)
• Heavy smoking (smoking >10 cigarettes/day)
• Known or suspected non-compliance, drug or alcohol abuse
• Pregnancy
• Active periodontitis (probing pocket depth >4 mm)
• Pharmacological treatment or antibiotic therapy during or up to three months before the study