Years ago, when the development of modern implantology was still in its infancy, scientific interest was focused mainly on the problems of osseointegration and bone augmentation in terms of improving the implant site. In contrast to the past, diseases of the tissues around implants now represent a major problem in dental practices worldwide.
Inflammatory processes around implants do not have a single, simple cause, so identifying the cause is crucial when selecting therapy. The presence of a pathological biofilm is most often the main cause of this condition. It is known that patients who show signs of periodontal disease have significantly greater probing depths around dental implants, greater bone loss and signs of peri-implantitis than patients who otherwise show no signs of periodontal disease.
In many cases, the cause of peri-implant diseases is relatively easy to identify, because it may be an improperly designed prosthetic construction that is difficult or impossible to clean, or simply residual cement beneath a cemented construction. Therapy therefore requires replacement of the construction, which in most cases is not harmful to the implant itself. Treatment is considerably more difficult and unsuccessful when the causes lie in incomplete regeneration and osseointegration of bone substitutes. Infected portions of bone or bone substitutes must be removed as soon and as thoroughly as possible, and the implant and its site must be decontaminated.
An implant is dead foreign tissue whose surface is designed to provide the best possible conditions for good osseointegration, but at the same time this also enables unfavourable biofilm to accumulate on its surface. Treatment of the disease is therefore aimed primarily at removing the plaque layer from the implant surface as quickly and precisely as possible and preventing it from accumulating again. Systemic administration of antibiotics in the case of inflammation is usually unsuccessful, because the implant is dead, non-vascularized tissue, so the antibiotic does not reach the bacterial plaque on its surface. Short-term effects of this type of therapy are visible only in the surrounding soft tissues. For the same reason, the use of disinfectant solutions is also unsuccessful, because they too cannot penetrate to the actual cause. In addition, their use often leads to side effects resulting from prolonged use and increasing concentrations. Microbial resistance and fungal superinfections therefore require additional therapies that likewise do not have a certain outcome.
In the last few years, research into removal of biofilm from the implant surface has led to numerous conclusions, all of which support local action, and antimicrobial photodynamic therapy has become established as one of the main treatment methods.
Different protocols have become established in practice, but all share a photodynamic mechanism that effectively reduces the amount of bacteria on the implant surface and in the surrounding tissues. Based on my own practice and other clinical documentation, the following method is very successful: a sterile light-activatable solution (HELBO blue; Bredent Medical; Senden) is applied to the infected and diseased area. The dye is removed by rinsing with physiological saline after 60 to 180 seconds. During this time, dye molecules are deposited on negatively charged areas of the bacterial wall. After the exposure time, the dye molecules are activated with cold laser light (HELBO TheraLite laser, Bredent Medical, Senden). During activation, energy is absorbed by the dye molecules. A change in the spin state of the electrons produces oxygen free radicals, which immediately react with lipid molecules in the bacterial wall and irreversibly damage it. Fungi in the biofilm are destroyed in a similar manner. In this way, the implant surface and diseased surrounding tissue are decontaminated. Because of the membrane potential of eukaryotic cells (tissue), the dye does not bind to them, which means that it acts exclusively on the prokaryotic cells of pathological bacteria.
At the beginning of the disease, peri-implant mucositis develops, when the problem is still limited to the soft tissues. In this case, it is advisable to eliminate the cause of the inflammation as quickly as possible before it spreads to the hard bone tissues. It is advisable to remove the construction and clean it outside the oral cavity. Components that cannot be removed are cleaned in the mouth with ultrasound and scalers, and finally decontamination is performed using the aPDT method.
If the disease progresses, infection and damage occur in the hard tissues that form the implant site. On a radiograph, the problem appears as a bone defect, and clinically as purulent discharge from the peri-implant pocket. In the treatment of vertical defects > 4 mm, open curettage and a broad-based flap are required. The area is disinfected using the aPDT method. Augmentation up to the upper edge of the implant is most often unsuccessful because the required volume cannot be achieved in vertical bone reconstruction. If an excessive amount of bone substitute is used, secondary infection often occurs, leading to even greater loss of bone mass. Compared with bone augmentation around teeth or in defects of bone ridges, the procedure is less successful in this situation. For this reason, augmentation with autologous bone particles is recommended.
Inflammatory processes around implants do not have a single, simple cause, so identifying the cause is crucial when selecting therapy. The presence of a pathological biofilm is most often the main cause of this condition. It is known that patients who show signs of periodontal disease have significantly greater probing depths around dental implants, greater bone loss and signs of peri-implantitis than patients who otherwise show no signs of periodontal disease.
In many cases, the cause of peri-implant diseases is relatively easy to identify, because it may be an improperly designed prosthetic construction that is difficult or impossible to clean, or simply residual cement beneath a cemented construction. Therapy therefore requires replacement of the construction, which in most cases is not harmful to the implant itself. Treatment is considerably more difficult and unsuccessful when the causes lie in incomplete regeneration and osseointegration of bone substitutes. Infected portions of bone or bone substitutes must be removed as soon and as thoroughly as possible, and the implant and its site must be decontaminated.
An implant is dead foreign tissue whose surface is designed to provide the best possible conditions for good osseointegration, but at the same time this also enables unfavourable biofilm to accumulate on its surface. Treatment of the disease is therefore aimed primarily at removing the plaque layer from the implant surface as quickly and precisely as possible and preventing it from accumulating again. Systemic administration of antibiotics in the case of inflammation is usually unsuccessful, because the implant is dead, non-vascularized tissue, so the antibiotic does not reach the bacterial plaque on its surface. Short-term effects of this type of therapy are visible only in the surrounding soft tissues. For the same reason, the use of disinfectant solutions is also unsuccessful, because they too cannot penetrate to the actual cause. In addition, their use often leads to side effects resulting from prolonged use and increasing concentrations. Microbial resistance and fungal superinfections therefore require additional therapies that likewise do not have a certain outcome.
In the last few years, research into removal of biofilm from the implant surface has led to numerous conclusions, all of which support local action, and antimicrobial photodynamic therapy has become established as one of the main treatment methods.
Different protocols have become established in practice, but all share a photodynamic mechanism that effectively reduces the amount of bacteria on the implant surface and in the surrounding tissues. Based on my own practice and other clinical documentation, the following method is very successful: a sterile light-activatable solution (HELBO blue; Bredent Medical; Senden) is applied to the infected and diseased area. The dye is removed by rinsing with physiological saline after 60 to 180 seconds. During this time, dye molecules are deposited on negatively charged areas of the bacterial wall. After the exposure time, the dye molecules are activated with cold laser light (HELBO TheraLite laser, Bredent Medical, Senden). During activation, energy is absorbed by the dye molecules. A change in the spin state of the electrons produces oxygen free radicals, which immediately react with lipid molecules in the bacterial wall and irreversibly damage it. Fungi in the biofilm are destroyed in a similar manner. In this way, the implant surface and diseased surrounding tissue are decontaminated. Because of the membrane potential of eukaryotic cells (tissue), the dye does not bind to them, which means that it acts exclusively on the prokaryotic cells of pathological bacteria.
At the beginning of the disease, peri-implant mucositis develops, when the problem is still limited to the soft tissues. In this case, it is advisable to eliminate the cause of the inflammation as quickly as possible before it spreads to the hard bone tissues. It is advisable to remove the construction and clean it outside the oral cavity. Components that cannot be removed are cleaned in the mouth with ultrasound and scalers, and finally decontamination is performed using the aPDT method.
If the disease progresses, infection and damage occur in the hard tissues that form the implant site. On a radiograph, the problem appears as a bone defect, and clinically as purulent discharge from the peri-implant pocket. In the treatment of vertical defects > 4 mm, open curettage and a broad-based flap are required. The area is disinfected using the aPDT method. Augmentation up to the upper edge of the implant is most often unsuccessful because the required volume cannot be achieved in vertical bone reconstruction. If an excessive amount of bone substitute is used, secondary infection often occurs, leading to even greater loss of bone mass. Compared with bone augmentation around teeth or in defects of bone ridges, the procedure is less successful in this situation. For this reason, augmentation with autologous bone particles is recommended.
