IMPLANT MUCOSITIS

The present invention refers to an implant fixture suitable for detecting pathological states of peri-implantitis or peri-implant mucositis early, by coloring inside the mouth, for example the tongue or a gum, in correspondence with the implant fixture itself, so as to allow a timely medical intervention on the patient.

A dental implant is a medical-surgical device, inserted into the maxillary and/or mandibular bone, which acts as a support for a prosthetic replacement of the teeth. It is used to functionally and aesthetically rehabilitate the loss or lack of one or more teeth.

Dental implant failures are usually due to biophysical and biomechanical biological problems occurring simultaneously. Biological-based failures are mostly associated with the accumulation of microbial plaque and bacterial infections, generally hesitating such as peri-implantitis, in which implant design plays an important role.

When signs of peri-implantitis or peri-implant mucositis occur, medical therapies may not be sufficient or early In this case it is necessary to resort to surgical therapies, which involve resection of the affected tissues, extraction and decontamination of the endosseous implant structure, followed by a bone graft, where a lot of healthy tissue has been lost, applying new implants made with materials that they can enhance the processes of osseointegration with the host tissue and, at the same time, prevent or suppress bacterial colonization.

At present, an approach that clearly leads to complete clinical success in the treatment of peri-implant diseases is not known. Peri-implant lesions show a well-defined biological organization, not only in terms of inflammatory cells, but also with respect to biological and biochemical components: in particular, the presence of reactive oxygen species (ROS) has been linked to the inflammatory environment peri-implant that affects the correct clinical course of the infectious disease that can affect the health and survival of the implants. Indeed, peri-implantitis appears to be linked to an increase in the production of reactive oxygen species (ROS), which are closely related, in turn, to inflammation. Other recent studies have shown an association between oxidative stress and periodontal inflammation leading to alveolar bone loss and periodontitis. In this context, an appropriate approach would be to treat peri-implantitis with antioxidant agents that reduce the activity of RANKL-related osteoclasts, to prevent/reduce/treat peri- implantitis lesions at different stages. The implant can fail due to microbiological variables, especially bacterial, depending on the peri-implant environment, the implant surface in contact with biological tissues, the patient and his immunological/biological response, the operator and his pre-procedures./intra/post-implant surgery. Currently the actions that can be carried out are:

- trans-tissue delivery of antibacterial/bacteriostatic agents;

- functionalization (by subtraction) of the implant surfaces with variation of the surface texture in order to make it less susceptible to bacterial contamination; - additive (by addition-surface coating that can be conveyed with numerous techniques) of the implant surfaces with variation of the surface texture in order to make it less attackable by bacterial contamination.

The implant can also fail due to physicochemical variables, in particular relating to the variation in pH typically triggered by the contamination of acidogenic and acidophilic bacterial species which in turn trigger pro-inflammatory and osteolytic biological pathways, dependent on the peri-implant environment, implant surface in contact with biological tissues, from the patient and his immunological/biological response, from the operator and his pre/intra/post-implant surgery procedures: on these variables it is possible to implement corrections deriving from the inventive step described here .

In this second case, the actions currently available are: - trans-tissue delivery of antibacterial/bacteriostatic and basic

PH agents in order to counteract the destructive action accompanying the inflammatory process;

- functionalization (by subtraction) of the implant surfaces with variation of the surface texture in order to make it less attackable by bacterial contamination, - additive (by addition-surface coating that can be conveyed with numerous techniques) of the implant surfaces with variation of the surface texture in order to make it less attackable by bacterial contamination. However, these corrective actions have some drawbacks.

A first drawback of said corrective actions consists in the fact that the wash-out of the local therapy is rapid; effectiveness depends on proper therapeutic planning and requires numerous follow-ups. Furthermore, the application of this therapy depends on the objective clinical manifestation of peri-implantitis, therefore the presence of a doctor would be required to object to the pathological process in progress.

A second drawback consists in the fact that the textures can act on some bacterial species, consistent with the steric hindrance between the bacterial morphology and the trabeculae of the texture. The creation of a first form of bacterial aggregation (envelope) around the functionalized implant would in any case create a valid substrate for the creation of growth not in direct contact with the implant but in any case in the peri-implant sulcus, creating indirect damage inflammatory type. A third drawback consists in the fact that the wash-out of the local coating layer is rapid, which can only be used for a short period following implant insertion (slow-releasing), the effectiveness depending on the correct characterization of the type of therapeutic approach site-specific of the coating and in any case does not protect against any infectious processes in the following post-surgery months.

Object of the present invention is to at least partially overcome the drawbacks complained of through the use of an implant fixture, in accordance with claim 1, capable of detecting autonomously and early on the onset of pathological states compatible with peri-implant mucositis, which can evolve in early stages of peri-implantitis, in order to allow prompt medical intervention on the patient. Said implant fixture, which is inserted in the maxillary and/or mandibular bone, is characterized in that it provides an internal cavity, put in communication with the outside through at least one opening, in which:

- said internal cavity is filled with a highly coloring biocompatible fluid; - said at least one opening is kept inaccessible due to the presence of a chemical compound (carrier) that can be attacked by one or more components present in the crevicular and/or salivary fluid; in such a way that, following a retraction of the gingiva following an inflammation and loss of peri-implant bone substance, even of a few millimeters, said crevicular and/or salivary fluid comes into contact with the implant fixture in correspondence with said at least one opening , due to the loss of bone in which said implant fixture is inserted, said chemical compound degrading and allowing the dye fluid to escape which will cause the coloring inside the mouth, for example the tongue or a gum, in correspondence with the fixture and the entire oral cavity, highlighting the presence of said inflammation and loss of peri-implant bone substance.

If antibiotic and/or bacteriostatic substances and/or pro- osteogenic growth factors are present in the coloring fluid, the implant fixture according to the invention will provide a first treatment of the infection in progress.

Preferred embodiments and non-trivial variants of the present invention form the subject of the dependent claims.

It is understood that all attached claims form an integral part of the present description.

The present invention solves the above drawbacks since the "release in situ" of said coloring fluid will create in the patient a "clear, intelligible and unavoidable" perception that something is happening to his or her oral cavity, creating the urgent conditions for a request for dental visit.

By alerting the patient, he will have full awareness of usually sub-clinical processes that become evident only after months and in any case when the inflammatory and osteolytic process is already severe.

It will be immediately obvious that innumerable variations and modifications (for example relating to shape, dimensions, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention, as appears from the attached claims.

The present invention will be better described by some preferred embodiments, provided by way of non-limiting example, with reference to the attached drawings, in which:

- FIG. 1 (a, b, c) are three views of a first embodiment of the implant fixture according to the present invention; - FIG. 2 (a, b, c) are three views of a second embodiment of the implant fixture according to the present invention;

- FIG. 3 shows the structural formula of a chemical compound (chitin) used in the construction of the implant fixture according to the invention.

With reference to FIG. 1 (a, b, c), (1) designates an implant fixture, in which a first (2), a second (3) and a third (4) circumferential cavity are identified, for example with annular morphology. The first circumferential cavity (2) is placed in the upper part, at a distance of 3 ÷ 5 mm from the upper edge of the implant fixture (1).

The second circumferential cavity (3) is placed lower, at a distance of 5 ÷ 7 mm from the upper edge of the implant fixture (1). The third circumferential cavity (4) is placed even lower, at a distance> 5 mm from the lower edge of the implant fixture (1).

According to a preferred embodiment (not shown) the implant fixture (1) is provided with only the first (2) and second (3) circumferential cavities.

According to a further preferred embodiment (not shown) the implant fixture (1) is provided with only the first circumferential cavity (2).

Said circumferential cavities (2, 3, 4) are connected with a cavity (5) obtained inside the implant fixture (1) through one or more openings (2a, 3a, 4a), for example four for each of the circumferential cavities (2, 3, 4).

According to a preferred embodiment, an implant fixture (10), shown in FIG. 2 (a, b, c), is devoid of circumferential cavities (2, 3, 4), while there is at least one of the openings that connect the internal cavity (5) with the outside. In the illustrated case, the openings (2a) and (4a) are present, corresponding to the circumferential cavities (2) and (4).

Inside said circumferential cavities (2, 3, 4), in the case of the implant fixture (1), and in the openings (2a, 4a), in the case of the implant fixture (10), there is a "carrier" structure composed from polysaccharides of animal origin, for example chitin in solid, semisolid or gel state, the structural formula of which is shown in FIG. 3.

Chitin is a natural polysaccharide formed by N-Acetyl-D- glucosamine residues linked by b1-4 bond. It constitutes the exoskeleton of crustaceans and insects and the cell wall of fungi and yeasts. It is insoluble in most organic solvents and this characteristic makes its use as it is and its chemical-physical characterization very difficult. It has low toxicity and is inert in the gastrointestinal tract of mammals.

Chitin is only degradable by chitinase, lysozyme and ptyalin. Lysozyme and ptyalin are typically present in fluids that cover anatomical areas (e.g. tears, saliva, crevicular fluid). In the case of the peri-implant sulcus, it has the presence of lysozyme and ptyalin only in the region of the implant neck. The more the collar is exposed as a result of inflammation and loss of bone substance, the greater the area of the implant surface will be exposed to the action of crevicular fluid and therefore of lysozyme.

Inside the cavity (5) there is a coloring agent, for example erythrosine or toluidine blue.

Erythrosine, otherwise called E127 in the European coding of food additives, is an intense red food coloring, which belongs to the chemical class of organoiodides, in particular it is the disodium salt of 2,4,5,7-tetraiodiofluorescein.

Erythrosine E127 is also commonly used as a dental plaque detecting agent.

Should the collar, due to inflammation and loss of bone substance, be discovered, the crevicular fluid, and therefore the lysozyme, would come into contact with the carrier, attacking it chemically and the coloring agent contained in the reservoir (5) would come out of the openings (2a , 3a, 4a) and would cause staining inside the mouth, such as the tongue or a gum.

The "in situ release" of E127 will create in the patient a "clear, intelligible and unavoidable" perception that something is happening to their oral cavity, creating the urgent conditions for a request for a dental visit.

The simple coloring released by the carrier ring has a diagnostic effect (the release of the dye that "alerts" the patient) and therapeutic (the release of antibiotic and other site-specific therapeutic factors).

In addition to erythrosine, any dye, such as toluidine blue, could be used.

In addition to antibiotics, bacteriostatic, pro-osteogenic growth factors or other bioactive substances can be used.