Implants – What is an implant?

The dental implants used today are usually cylindrical or slightly conical screws (the shape of the tooth root) and normally 6-18 mm long and 3-6 mm in diameter. In the head of the implant is a small internal screw thread for attachment of the support post (known as the abutment). Depending on the use (crowns, bridges, dentures) there are various kinds of abutments.

There are innumerable implant manufacturers on the market but only few systems are supported by scientific studies and long-term results. In our practice we use implants from the following manufacturers:

• Straumann (Switzerland)
• Nobel Biocare (Sweden/Switzerland)
• Noris Medical (Israel)

These manufacturers are market leaders with decades of experience and continuously improved systems backed by excellent long-term results.

Careful planning is the first step preceding an implant operation. The examination of the patient begins with careful inspection of the oral cavity and palpation of the jawbones. X-rays are taken to determine the available height of the bone. In straightforward cases it is sufficient to take a panoramic X-ray of the entire mouth (orthopantomogram, abbreviated OPG or OPT), possibly complemented by small dental X-rays taken inside the mouth.

In more difficult cases in which the amount of available bone is limited and we have to operate in the proximity of sensory nerves, for example, we have a computed tomographic (CT) scan of the jaw done. Cone beam volumetric tomography (CBVT or DVT) is a new type of computed tomography which has been developed specially for the head region. In comparison to normal computed tomography CBVT involves up to 80% less radiation exposure. The radiation dose of CBVT is therefore approximately the same as that of a normal panoramic X-ray (OPG). You can find further information on X-rays and CBVT here.

Another option, particularly for larger operations such as bone augmentation or full-mouth reconstruction, is treatment under general anaesthesia. Treatment under general anaesthesia can be performed in our own operation theatre, in which case we call in an experienced team of anaesthesiologists.

As soon as the local anaesthetic has taken effect the gum is carefully opened. With a sequence of calibrated burs, the implant bed in the bone is prepared. To prevent overheating of the bone, preparation is done with sterile water cooling. The suitable implant is chosen and carefully inserted. The gum tissue is replaced over the implant and secured with sutures (stitches) and a provisional denture or bridge is fitted. In the case of template guided implantation the operation can be even performed as a closed procedure, that means without cutting open the gum tissue at all.

Computed tomography or cone beam volumetric tomography produces precise three-dimensional images of the jawbone on a 1:1 scale and permits optimal planning of the implant operation. The three-dimensional imaging permits exact measurement of the amount of available bone. The optimal positioning, length and diameter of the implants can now be planned on the basis of the available bone, as well as any necessary bone augmentation. The images also give us information about the quality of the bone (solid or porous). The CT or CBCT images also show the exact position of the nerves running through the bone as well as other structures which we must be careful to avoid injuring during the operation. This means considerable extra safety for the patient.

A further use of the three-dimensional images is for computer guided implantation, which is the safest and least traumatic method of all for the patient.

Single-tooth implant

If a single tooth is missing and replaced by an implant we call this a single-tooth implant. In the past a gap caused by a single missing tooth was usually closed by a bridge. The filing down of the adjacent teeth that this involves is not necessarily a good idea, particularly if these are healthy teeth with no signs of tooth decay. It can sometimes result in the death of the tooth nerve (dental pulp) and a consequent need for root canal treatment. Also, the crown margins often provoke gum recession with poor cosmetic results.

In the case of a single-tooth implant the missing tooth is replaced by an implant which is inserted in place of the lost dental root. During the healing phase of usually a few weeks the implant remains under the gums without loading. During this time the patient can wear a provisional prosthesis which can be either removable or fixed (e.g. adhesive bridge). After uncovering the implant and taking an impression the crown that has been made in the dental laboratory is attached to the implant.

If a tooth has to be extracted, the implantation can be performed at the same time as the extraction. This is called an immediate implant. This spares the patient an additional visit and is a standard procedure today. Only in some cases, e.g. in the case of an acute infection, is it better to first remove the tooth and wait until the gum and bone tissue has healed before placing the implant. If the implant is fitted with a firmly attached provisional crown immediately after implantation, this is called immediate loading. This procedure is, of course, particularly comfortable for the patient because he leaves the practice with a fixed tooth replacement and does not need a provisional bridge or denture. However, immediate loading is not possible or advisable in all cases and the implantologist needs experience to weigh up the potential benefits and risks in the individual case.
 

Case from our practice: Single- tooth implants

Our 27-year-old patient S.G. was dissatisfied with the cosmetic appearance of her front teeth. Her two lateral incisors had been missing since birth. On the right the corresponding milk tooth was still there, while on the left the canine tooth had taken the place of the missing incisor and the milk tooth was behind it. She was particularly unhappy about the gaps and the asymmetric gum contours. We removed the two milk teeth and replaced them with implants. We evened out the gum margins by surgically extending the crowns. After bleaching, we then installed all-ceramic crowns on the implants and provided the adjacent front teeth with ceramic veneers. The implant crowns are now indistinguishable from the natural teeth.

In addition, the continuous pressure of the dentures causes shrinkage of the jawbone due to accelerated bone loss (also known as bone resorption or atrophy) and thus leads to an even worse fit of the dentures. Poorly fitting dentures do not provide adequate support for the tissues of the face, particularly the lips, which makes the patients look older and encourages the development of premature wrinkles. The psychological effect should not be underestimated either as for many people full dentures symbolise old age.

With dental implants we can now break this vicious circle. Only 2-4 implants fitted with studs or other attachments are sufficient to give a full denture stable support. With more sophisticated constructions it is possible in most cases to anchor a fixed bridge in a completely toothless (edentulous) jaw. The old dream of new fixed teeth has now become reality and enables many people to regain an important piece of quality.

For many years now, one of our key areas of expertise has been the rehabilitation of toothless patients and full reconstruction in patients who have to have all their teeth removed. In the following we give you an overview of the most important methods used in our practice for removable and fixed dental restoration in toothless jaws.

Bar prostheses

1st case study from our practice: Removable tooth replacement on implants

55-year-old patient after full reconstruction with 4 implants in the lower jaw and bar-anchored removable dentures. The firm hold of the dentures ensures comfortable chewing.

2nd case study from our practice: Removable tooth replacement on implants

This 39-year-old patient, a former photo model, had had major reconstruction done several years ago in Eastern Europe. All her teeth had been crowned. Unfortunately the work had been done so badly that the patient had developed massive periodontal disease and tooth decay under the crowns. When she came to see us she was suffering from severe depression because she was ashamed to show her teeth in public.

All the teeth in the upper jaw had to be removed. On account of the considerable bone loss we decided in this case to fit bar-retained dentures on 8 implants. The extractions, bone augmentation and implant placement were performed in the same session under general anesthesia.

Computer guided implantation:

The digital data obtained in this virtual implantation are then used to prepare a three-dimensional template made of plastic or titanium. This drilling template is placed in the patient’s mouth during the implant operation. Drill sleeves in the template guide the bone drill during the implantation and ensure that the implants are placed exactly in the ideal position planned on the computer. The benefit for the patient is that the gums often do not have to be opened (no swelling, practically no pain after the procedure). A further advantage of template guided implantation is the possibility of preparing an exactly fitting provisional bridge before the implant placement. This means that ideally the patient can go home with fixed, functional teeth shortly after the implant placement. In order not to raise false expectations and give you honest information we should, however, mention that at the present time computer guided template implantation is not possible or appropriate in all cases. We always use this particularly safe and gentle method if it brings the patient concrete benefit.

Dynamic computer-guided navigation:  The X-Guide system

As one of the first practices in Switzerland, we are equipped with X-Guide, a system for dynamic navigated implantation. Two optical sensors, which are attached to the drill and to the patient’s jaw, enable free 3-D navigated surgery without any splints. The current position of the drill or implant is permanently displayed in three dimensions on the screen and compared with the previously planned ideal positioning.

In contrast to the rigid template-guided method, we can navigate freely with the X-Guide. Especially in the complex cases that we often treat, it is often necessary to deviate from the planning during the operation. The X-Guide gives us this possibility and therefore enables flexible and safe operation even in unpredictable situations.

Vorteilhaft für den Patienten ist, dass die Schleimhaut oft nicht einmal eröffnet werden muss (Keine Schwellung, kaum Schmerzen nach dem Eingriff). Ein weiterer Vorteil der computergeführten Implantation ist die Möglichkeit, bereits vor der Implantation eine passgenaue provisorische Brücke herzustellen. So können wir den Patienten im Idealfall kurz nach der Implantation mit festen, belastungsfähigen Zähnen versorgen und nach Hause entlassen. Um keine falschen Erwartungen zu wecken und im Sinne einer seriösen Information muss allerdings darauf hingewiesen werden, dass eine computergeführte Implantation derzeit nicht in allen Fällen möglich oder sinnvoll ist. Wir wenden diese besonders sichere und schonende Methode immer dann an, wenn sie dem Patienten konkrete Vorteile bringt.

Case study from our practice: Full-mouth reconstruction with computer guided implantology

This 84-year-old woman could no longer cope with her old, poorly fitting dentures and came to us for advice about fixed tooth replacement on implants. On account of the patient’s advanced age we wanted to offer her the least traumatic, minimally invasive procedure possible.

First we obtained a CT scan with X-ray films placed in the upper and lower jaws (cone beam computed tomography (CBCT) with particularly low radiation exposure) in order to perform a three-dimensional analysis of the available bone. The evaluation of these X-rays showed that there was sufficient bone mass for immediate implant placement without bone augmentation using the All-On-4-method.

The planning of the optimal positioning of the implants in the bone and the determination of the diameter and length of the implant were performed virtually on the computer using the Med3D® software. The digital data thus obtained were sent to a specialised dental laboratory which fitted the X-ray templates with highly precise drill sleeves which serve to guide the drilling and the implants into exactly the previously planned correct position during implantation.

Then the operation could be performed with local anaesthesia. The remaining pivot teeth were removed. Then the templates were fixed in the mouth, the implant drilling performed through the drill sleeves, and the implants placed in the planned position, again using the template. The great advantage of the computer guided implantology is that it is no longer necessary to first open the gums with a scalpel and expose a large area of bone. As the implant position has already been planned on the computer the drilling can be performed minimally invasively through the closed gum tissue and the implants placed in the drill holes. According to the all-on-4 method, four implants were placed in each jaw.

The operating time was thus considerably shortened to about 45 minutes per jaw. The swelling and pain normally observed after major implant operations were almost entirely absent, there was no bleeding or bruising either.

As the implant positioning had already been decided preoperatively (before the operation), the dental technician was able to make the provisional restorations before the implant placement. These bridges were screwed onto the implants immediately after the operation (immediate loading).

The patient was able to leave our practice with fixed tooth replacement on implants. The definitive All-On-4 bridges were fitted after three months.

Case study from our practice: Zygomatic Implants

This 56-year-old patient consulted us because she had serious problems with her poorly fitting removable upper dentures. The X-ray and CT scan showed massive bone loss (atrophy) in the upper jaw so that placement of implants would have required prior major bone augmentation. For this bone graft we would have had to take bone from the hip. This is quite a stressful procedure for the patient. After the bone graft patients have to remain in hospital for a few days and there is often some difficulty walking in the first weeks after the operation due to the bone removal from the hip. In addition, in the initial phase not even provisional dentures can be used so as not to jeopardize the integration of the grafted bone. Then, for about nine months after the procedure, only a provisional removable full denture can be worn. It should also be mentioned that such large bone grafts have a relatively high failure rate of about 15-20%.

After thorough discussion of all the options, our patient therefore decided on zygoma implants. In an outpatient operation under general anaesthesia we removed the remaining teeth from the upper jaw and stably anchored four zygoma implants, two on each side, in the zygomatic bone. On the very same day we were able to install a fixed provisional bridge on the implants. Three months later the definitive prosthetic rehabilitation was performed.

Here you can access further scientific information on zygomatic implants and pterygoid implants

Case study from our practice: Immediate loading

54-year-old patient with severely compromised dentition. Periodontal gum disease and dental decay had led to such serious damage that it was no longer possible to save the teeth. The patient had suffered considerably from her cosmetic “disfigurement” and expressed a wish for full-mouth reconstruction under general anaesthesia with “permanent teeth” from the very beginning. It was important to her that she remained aesthetically presentable throughout the entire treatment period.

Under general anaesthesia all teeth in the upper and lower jaws were removed. In the same session we placed 4 implants per jaw. The All-On-4 method allows such stable anchoring of the implants in the bone that fixed, functional bridges can be installed immediately. On the same day, 4 hours after the operation the patient was fitted with fixed provisional bridges screwed onto the implants and was able to return to her home town. The definitive bridges were then fitted three months after the beginning of treatment.

How can peri-implantitis be recognised and how does it progress?

It is treacherous that peri-implantitis (like periodontitis) remains painless for a long time and is therefore often only noticed late. In the early stages, inflammation of the gums around the implant (mucositis) is the first sign with redness and possibly slight swelling of the gum line with an increased tendency to bleed.  Probing and measuring the gingival pockets usually reveals a slightly increased pocket depth. This inflammation of the gums (mucositis) is reversible, i.e. it can heal without consequences if it is treated locally and the cause is eliminated.

If the mucositis is not treated, it often turns into a “real” peri-implantitis with bone loss. The bacteria now attack the bone around the implant and break it down more and more (resorption). This creates a bone crater around the implant, which can only be detected with an X-ray, preferably an intraoral one.  Sometimes you will also find some pus oozing out around the implant. The probing of the gum pockets at the affected implants now shows – depending on the bone loss – clearly increased values. Pain only occurs later – if at all – so that the inflammation often remains unnoticed for a long time.

If peri-implantitis is not treated, it always leads to the loss of the affected implant in the end.

How to treat peri-implantitis

If the peri-implant inflammation is still confined to the mucosa, local treatment of the pocket can help. The dental hygienist cleans the implant surface and gently removes tartar and plaque. The bacterial biofilm can be gently removed with a powder jet device (Air Flow). With good oral hygiene, the mucositis can heal without consequences after the treatment. In some cases, repeated local treatments may be necessary.

If peri-implantitis has already led to a bone defect, it is no longer reversible and, if left untreated, will progress to the loss of the implant.  Therefore, a timely surgical revision is necessary. This involves opening the gums around the implant under local anaesthetic and exposing the bone. After removing the inflammatory tissue, the infected implant surface is decontaminated, i.e. freed from bacterial plaque. Special titanium brushes or powder jet devices can be used for this, but they often do not reach all points of the infected implant surface due to the depth of the bone crater. In our opinion, the best results are achieved with the new Galvosurge procedure. Exposed rough implant surfaces can also be smoothed and polished with small polishing instruments to prevent the accumulation of bacteria.

In some cases it is possible to fill the resulting bone defect with the patient’s own bone or bone substitute material and thus regenerate the lost bone.

The Galvosurge principle: The implant is covered with an electrolyte solution. An electrical voltage applied to the implant causes gas bubbles to form on the metal surface, which completely eliminate the infected plaque (biofilm). This makes successful bone regeneration possible.

You can see a video about the Galvosurge principle here:

Additional information on “Fixed teeth in one day – the All-On-Four technique”