Implantology

Cos’è What is it

Implantology is the dental branch that deals with replacing the missing dental elements with as many artificial roots inserted in the bone (Fig. 1) intended to support single teeth, groups of teeth or act as a support for a total prosthesis (the so-called overdenture). The main advantage of this method is to obtain an aesthetic, functional and phonetic restoration of the missing elements, reproducing a totally natural effect.

Fig. 1 – implant

A very important concept in implantology and which certifies its success or failure, is that of osseointegration, i.e., the mechanism by which the bone comes into intimate contact with the implant without interposing non-bone material between these two (in this case we speak of fibro integration which is equivalent to implant failure). In short, it is as if the bone intimately embraces the implant in order to fill any gap between these two elements.

For osseointegration to occur, it is essential that the implant does not undergo movements greater than 150 microns during the healing period. This is the concept of primary stability, which must be achieved during the surgical phase. Clearly, the softer the host bone is, the more difficult it will be to obtain good primary stability, the harder the bone is and the easier it will be to obtain it. Even in soft bone, with the new under-preparations it is possible to obtain excellent primary stability.

There are, therefore, surgical techniques that will allow us to obtain excellent stability even in unfavorable bone conditions, which are studied using pre-operative dentalscan.

Implants are nothing more than artificial roots made of titanium (Fig. 2) as numerous studies have shown that only this material proves to be absolutely tolerated by the body without causing rejection phenomena (we speak of biocompatibility). However, in a minority of cases (about 3%) the phenomenon of implant failure occurs for reasons that are not always perfectly known and foreseeable with consequent formation of fibrous tissue between implant and bonne and subsequent implant failure. In this minority of cases, the only alternative is the removal of the implant, a waiting period that allows the bone to heal properly and the subsequent placement of an implant.

In our center, in the event of implant failure (3 out of 100), the implant is repositioned without any additional outlay be the patient.

Fig.2 – An example of dental implant

Who can deal with it

Almost everyone! The patient must be evaluated from a general health point of view, the quantity and quality of bonne available at the implant site as well as the patient’s real motivations.

Contraindications to implantology: however, there are some contraindications of a local or general, temporary or permanent nature that strongly advise against implant therapy. For this reason, it is essential that the patient provides, through the appropriate medical questionnaire, all the information regarding his general and local state of health.

1. General contraindications: it is not advisable to undergo an implant surgery in the case of a state of pregnancy in progress. It is also not possible to perform any intervention if the patient is being treated with anticoagulant or immunosuppressive drugs. Anemias, alterations in the immune defenses and coagulation mechanisms, juvenile diabetes, are also absolute contraindications to implantology. In the case of cardiovascular diseases, the presence of heart valve prostheses, or previous bacterial endocarditis, there are high risks that must be carefully evaluated with the treating cardiologist. Finally, in the case of bone diseases (osteoporosis for example) in which there is the intake of drugs from the bisphosphonate family, implant surgery must be excluded.
2. Local contraindications: the main factor to be taken into consideration concerns the quantity and quality of the bone in the implant site. To obtain this evaluation, various diagnostic means are used (analysis of radiographs, models, etc.). Especially with the aid of a CT scan (TC Dentalscan), a precise measurement of the height and thickness of the bone as well as of the shape is obtained. In particular, attention must be paid to two anatomical structures that must be preserved in all ways: the maxillary sinus in the upper arch and the mandibular canal in the lower arch. The mandibular canal houses the nerve that carries the sensitivity to the teeth of the corresponding lower hemiarchy as well as to the hemi lip and hemilinguall. Therefore, an offense to this structure during the operation means a loss of sensitivity in these areas.
3. Age limits: age itself does not constitute a contraindication to the use of implants. However, an older patient may be more likely to have health problems that do not recommend surgery. As far as the young patient is concerned, the bone development of the jaws must be assessed on a case-by-case basis. However, it is not possible to place implants in young patients before growth is complete (18 years for females and 20 years for males).

How to deal with it

1. Maintaining the implants for the long term: it is absolutely essential to perform regular check-ups, generally every six months, in which the dentist will check the health of the peri-implant tissues as well as the evaluation of the prosthetic structures fixed to the implants. It will also assess the degree of oral hygiene practiced by the patient. In fact, it is believed that the control of bacterial plaque represents the determining factor for long-term implant success. For this reason, the patient must be instructed on how to use the means for controlling oral hygiene at the level of implants and residual teeth. Furthermore, the patient’s ability to maintain an adequate state of oral hygiene must be assessed after some time. Professional hygiene sessions practiced 3 times a year are also necessary.
2. Planning: there is no correct implantology without careful planning. The patient who will have to undergo the surgery must be carefully analyzed both clinically and radiographically (with the aid of the CT scan) in order to evaluate with the utmost precision the factors that are decisive for a perfect success of the therapy. This will allow us to choose the exact number of implants to be inserted as well as their size in relation to the amount of bone available. To all this is added an in-depth discussion of the patient’s needs and expectations also in relation to their economic possibilities.

What the intervention consists of

After an in-depth interview with the patient (in which the various therapeutic possibilities and any risks are stated) and after having given consent to the treatment, the implant is inserted in the pre-established site under local anesthesia (only in particularly patients anxious or in major interventions, conscious sedation is used). The surgery lasts from 20 minutes to about an hour and does not involve any particular post-operative discomfort. The only annoyances can be represented by swelling in the affected area and pain generally treatable with common painkillers on the market. In any case, each patient will be given a sheet with all the drugs and recommendations to be followed in the period immediately following the surgery and in following days. In this way, post-operative discomfort is reduced to a minimum. In the case of particularly anxious patients (odontophobia) or in the case of large implant rehabilitations, conscious sedation is used. This procedure, performed by an anesthetist, produces a sense of relaxation in the patient while keeping him perfectly aware of what is happening around him (in fact, the patient answers our questions but is considerably calmer and more relaxed). The removal of the stitches is deferred to about a week after the intervention.

In order to move on to the next prosthetic phase, it is necessary to wait a period of about 6 weeks for the mandible and 3 months for the upper jaw. These times are lengthened (6 months) in case of the bone regeneration interventions as it is also necessary to wait the time necessary for the added bone to organize itself appropriately.

Complications and failure

The success rates in implantology are around 97%. However, there are several short and long-term complications that can lead to implant failure resulting in therapeutic failure. There may be early and late intraoperative or postoperative surgical complications but also prosthetic complications that occur late and are caused by a failure to integrate the implant due to the chewing load applied to it. Operational complications include non-compliance with the anatomical structures (maxillary sinus and mandibular canal). One of the most common postoperative complications is peri-implantitis, an inflammation of the tissues around the implant. It is caused by bacterial contamination of the implant surface and leads to bone replacement with granulation tissue and consequent loss of the implant. It should be noted that most failures occur in the early postoperative period and only rarely do we witness the loss of an implant after some time.

The regular checkups accompanied by a professional hygiene session aimed at restoring the peri-implant tissues in optimal health conditions are fundamental for the long-term maintenance of the implants. These are generally performed three times a year. I fact, it has been widely demonstrated that good plaque control is the main factor for the long-term success of implant therapy. In fact, the patient must be instructed in order to obtain excellent plaque control.