Peri-implantitis and Periodontitis are diseases sharing the same microbiota found in the periodontal lesions (pockets), which causes damage that results in the loss of the supporting tissue.
The term peri-implantitis refers to an infection that characterises the inflammatory changes localised in the tissues surrounding implants. The inflammatory processes that are triggered initially involve the gum adhering to the implant ,and then progress further down. In this way, there is resorption of the bone, leading to the progressive mobility of the implant, which, at times, varying from case to case, eventually gives rise to the loss of the implant.
The insertion of dental implants is a procedure stemming from the need to restore functionality to those dental elements that have been lost due to periodontal disease or caries. The titanium screw of the implant is inserted into the bone by micro-invasive surgery. Following this, there is a healing process of the tissues called osseointegration. The tissues of the body, therefore, have to adapt to this new situation and ‘accept’ the screw that has been inserted. The tissues that form are effectively able to maintain the health of the implant.
The formation of a barrier of soft tissues around the implants prevents the bacteria that is naturally present in the mouth invading from the underlying tissues. These tissues consist of:
• junctional epithelium
• connective tissue.
The difference existing between the tissues surrounding natural teeth and implants mainly lies in the direction of the fibres that make up the connective tissue the connective tissue. The fibres are parallel around implant, not perpendicular, and there is a smaller number of fibres in a circular pattern. There is no periodontal ligament in the implant and the root cementum is non-existent. This gives rise to a weaker anchoring.
These problems can give rise to loss of the dental implants.
Implants prior to the new technologies
In the past, before osseointegrated implantology was established, the implants were subperiosteal (the implant did not enter into the bone). Any perimplantitis that develops pus and very painful inflammation is capable of destroying the entire jaw. The infection spreads quickly to the interface between the periostium-implant and between implant-bone, thus the implant became contaminated on all its surfaces and was treated as a foreign body.
With the advent of osseointegrated implantology, infection has a completely different pathology. Damage develops in a vertical direction and is of a crateriform type, with the prevalence of bone resorption linked to the subperiosteal implants.
The above differences are easily explained; the development of the infection takes place on the exposed surface of the titanium, which, in correctly osseointegrated implants, is minimal and is limited to the circumference of the screw. In subperiosteal implants, however, it involves the entire implant surfaces from the early stages.
The perimplantitis affects the implant right from the beginning, during the first hours after surgery, causing failure of the osseointegration with rapid loss of the implant.
These problems can give rise to loss of the dental implants.
Classification of perimplantitis
The types of perimplantitis can therefore be classified merely by using a chronological criterion:
- Early, when it develops before completion of the osseointegration process
- Late, when it develops once the osseointegration is completed, often manifesting after the prosthetic loading process has taken place.
The late diseases can be clinically classified as follows:
- Mucositis, inflammation that only involves the mucous membranes covering the implants. The mucosa becomes inflamed and may bleed. If intercepted and treated early, this process is reversible;
- Symptomatic perimplantitis– asymptomatic perimplantitis with inflammation involving the mucosa and the bone. In this case, the lesion is radiographically visible.
It is clinically possible to observe bleeding, depth of the pathological probing, tender to percussion and changes in the colour of the gums surrounding the implant.
The X-ray shows two implants with perimplantitis: the larger lesion affects implant number 46 (the one on the right) where you can see bone reabsorption in both a vertical and horizontal direction. Clinically, the gum is a purple colour with bleeding and purulent exudate.
In healthy conditions, the implant screw must be fully inserted into the bone. This can be observed in the photo. There should not be any symptoms associated with a healthy implant.
The causes of perimplantitis and the loss of dental implants
The bacteria that cause perimplantitis are mainly anaerobic Gram-negative bacteria such as: Prevotella intermedia, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella nigrescens, Treponema denticola, and Bacteriodes forsythus. In fact, the bacteria on this list are the same ones that cause periodontitis. This suggests that it is essential to insert implants into a mouth that is not already affected by periodontitis as the same bacteria may easily migrate from a natural tooth to an implant. This can be more easily detected by carrying out a microbiological analysis. Below it is possible to see several analyses conducted on the infected implant in position 46 and 47, as well as on several teeth in the mouth.
Analyses carried out for implant 46 – affected by a severe form of peri-implantitis; the same bacteria are present, but in greater numbers
Analyses carried out for implant 47 – the composition of bacteria is similar to that found in the pockets of the teeth
Analyses carried out for teeth – the composition of bacteria is similar to that found in the pockets of the implants present in the same mouth
It can clearly be observed, albeit in different percentages, how the bacterial compositions are the same. This does not mean that it was not possible to insert implants in this particular mouth, but that natural teeth should have been decontaminated before inserting the implant screws.
Treatment must always be carried out in a timely manner. The presence of weaker tissues facilitates the compromising of the implant much more rapidly than with natural teeth.
The purpose of the treatment of implants affected by periodontitis is to decontaminate the peri-implant tissues of bacteria by removing the bacteria during professional oral hygiene and laser sessions.