What Is the Need for Implant Disinfection?
In the dental laboratory, during the customization and manufacturing process of a dental implant abutment, there is a microbial load accumulation on the titanium discs of either the implant abutment or on its surface. These microorganisms cannot only hamper osseointegration (bone-implant fusion) but also potentially contaminate the patient’s oral cavity and implant abutment fixing. Marginal bone loss (MBL) has been of paramount importance in dental implant success rate assessment; so, it has always been of great concern to preserve every tenth of a millimeter of alveolar bone around dental implants for which implant disinfection is primary in the laboratory.
C.albicans and E.faecalis have been detected in implant-abutment connection and peri-implant sulcus of implants affected by peri-implantitis, so most implantologists and researchers believe that implant-abutment connection site can be a potential microbial reservoir predisposing patients to periimplantitis. In addition to C.albicans and E.faecalis, A. baumannii has also been more frequently detected in the subgingival biofilm of seropositive HIV patients with periodontitis than healthy patients.
Surface disinfection not only helps eliminate pathogens on the implant surface but also reduces microbial load significantly. Er:-YAG, high-pressure steam, H2O2, and NaOCL groups could completely eliminate all the cultured microorganisms invivo or in-vitro studies as per current research. However, GaAIAs could not eliminate microorganisms completely. Descriptive results of microbial count after decontamination by diode laser are demonstrated in these studies, which proves that C.albicans was the only microorganism that was eliminated by all the decontamination procedures. Among resistant microorganisms, M.luteus and A.baumannii were the most resistant species.
What Are the Phases of MBL or Marginal Bone Loss?
Marginal bone loss (MBL) or bone loss around submerged implants occurs before implant-abutment connection, which seems to be inevitable but can be avoided by implant disinfection procedures in the dental laboratory. The second phase of MBL occurs after uncovering submerged implants until the delivery of the final prosthesis, and finally, the last but continuous phase of MBL occurs after the loading of implants or implant loading.
Proper soft tissue integration at the mucosal or transmucosal part of a dental implant is a prerequisite to seal the adjacent alveolar bone from the oral environment. Soft tissue attachment, as a barrier to the oral cavity, has a key role in preserving marginal bone height during the second phase and last phase of MBL. It is important to keep in mind that the quality of soft tissue attachment is influenced by the properties of the implant components that are in contact with the soft tissue.
During the fabrication procedure of the final prosthesis, implant abutments are sent to a dental laboratory and sent back to the dental office repeatedly. Hence, implant abutments become contaminated with various microorganisms and debris. Microorganisms and endotoxins can cause osteoclast activation (resorbing bone cell activation) and, consequently, subsequent bone resorption when there is a microgap due to debris that remained at the implant-abutment connection. Besides microgap formation, debris, such as titanium microparticles which are produced during abutment customization, can act as a foreign body and produce an inflammatory response, influencing soft tissue healing around implants to decontaminate abutments sent from dental laboratories before abutment connection to the implant.
What Are the Decontaminants Used for Surface Roughness and Implant Disinfection?
Decontamination of implant abutments may result in better soft tissue attachment and maintenance of marginal bone around implants because the application of a decontamination method can have an impact on different features of titanium surfaces. Higher surface roughness facilitates the accumulation of bacterial biofilm. It has also been shown that epithelial cells and fibroblasts adhere to machined titanium surfaces with higher strength when compared to rough surfaces.
Several studies have evaluated the effect of surface roughness on soft tissue integration on a microscale; however, there is a lack of evidence regarding the importance of nanoroughness in soft tissue integration. The key point in titanium abutment decontamination seems to be preserving and improving the chemical and topographic characteristics of the titanium surface while reducing or eliminating microorganisms at the same time.
As per current research, among the variety of different disinfectants, antimicrobial efficacy of plasma of argon and ultrasonic bath containing chemical decontaminants have been compared with high-pressure steam, which is commonly used in dental laboratories. Although both argon and ultrasonic cleaning plasmas could eliminate all the present microorganisms, unlike the high-pressure steam, these techniques have their own drawbacks. Ultrasonic cleaning is time-consuming; moreover, immersion of several abutments in a single ultrasonic bath may cause difficulty in finding the original site and direction of each abutment after decontamination. Despite the excellent antimicrobial and surface activation effect of plasma of argon, the device is not routinely present in dental clinics or laboratories. Hence, it seems necessary to evaluate other techniques that are more accessible and routinely used regarding their effects on microorganisms and titanium surface characteristics.
Chemical disinfectants such as sodium hypochlorite (NaOCL) and hydrogen peroxide (H2O2) are relatively common and easy-to-use disinfectants in dental clinics. However, a laser which is a novel technology is widely used by clinicians, and it is present in many clinics nowadays. Besides, laser irradiation makes it possible to disinfect an abutment in 1 or 2 minutes without those difficulties mentioned about immersion techniques.
Plasma treatment increases titanium surface wettability, but this is not unique to plasma treatment. A similar effect was shown for NaOCL and H2O2 treatments, which enhances epithelial cell growth on machined titanium surfaces. Different concentrations of chemical solutions and different settings of lasers have been used in the literature to decontaminate titanium surfaces.
Conclusion:
Among all the methods that could decontaminate machined titanium surfaces, a complete microbial elimination can be achieved in sodium hypochlorite (NaOCL), hydrogen peroxide (H2O2), high-pressure steam, and erbium-doped yttrium aluminum garnet (Er: YAG) lasers, as they are demonstrated to be equally effective in decontamination as well. However, among these, NaOCL remains the most effective agent for surface roughness increase. This important step of disinfection is a crucial step to dental implant success in implant dentistry.
