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Frequently asked questions - Implant reconstructive

General

What if the upper jaw doesn’t have enough bone in the posterior zone?

There are two possible solutions, and this will be discussed in extend during your consultation:

Either we place one or two zygomatic implant(s) (see the session on zygomatic implants)
Or we add bone in this specific area. In this area the implants are delayed for 3-4 months. Here, too, the patient is functioning on the more anterior implants, with a fixed provisional chrome cobalt teeth construction. This is then usually from premolar to premolar (10 teeth). Meanwhile the back area has all the time it needs to heal. More implants will be placed in that area later on.

Why is there loss of bone in the back of the upper jaw when teeth are lost?

Anatomically, the upper jaw crest is situated underneath the nose and the maxillary sinuses. When teeth get lost, the sinuses above the extracted teeth expand downwards fairly quicklyfht, due to the irresistible power of the respiration cycle. Furthermore, the resorption in the upper jaw is in a centripetal direction. This is due to the facial muscle actions, and this includes also the front area. The upper jaw has a centripetal resorption pattern of the bone. Hence the bony reconstruction in the upper jaw is best focused on adding volume on the outer side (vestibularly - on the outside). And this has an important aesthetic impact on the face. Furthermore, it makes it possible to place the implants in a more natural position. The lower jaw has a centrifugal resorption pattern of the bone, but this is easily overcome by adjusting the implant direction without any further aesthetics drawbacks.

I laugh quite expressively with some gummy smile. Will this transition line be in evidence?

The transition line is the horizontal line between the natural gum line and the artificial gum. It is very disturbing to see the transition line between both (i.e. your own gum tissues and the resin or porcelain gum). This can be the problem when gingival- artificial tissue is exposed in a full smile. In the facial examination for maxillary reconstructions it is therefore important to evaluate the patient at full smile and to observe if the patient shows a gingival smile in full animation. Prevention for this is purely planning at the time of implant placement. If necessary, and before placing the implants, you need to remove some crestal-alveolar bone or perform a mini-osteotomy in order to bring this line above the smile line. This means planning before you start. If you have a high smile line only the artificial pink should be visible. If this is technically not 100% achievable in full animation (in fact it always is, but sometimes an extra bony intervention is necessary), then this should be discussed with the patient as a part of the informed consent. Basically, this is an important consideration in the treatment protocol.

When I smile with my denture you see black corridors around my mouth corners. Can you eliminate this with my implant born bridge?

Buccal corridor is the word for the space between the buccal surfaces of the upper teeth and the corner of the mouth during smile and tolking. It refers to dark spaces (negative spaces) visible during the smile between the corner of the mouth and the back teeth. The wider the dark area of the vestibule showing during a smile (=large buccal corridor), the less attractive the smile. Broader smiles are considered more attractive. Minimal buccal corridors are the preferred aesthetic features in both men and women. Buccal corridors are directly related to the arch form. A full ‘U’ shaped arch form has little dark space, while a narrow ‘V’ shaped arch form shows larger black spaces. Once again, all this is balance. The buccal corridors should not be completely eliminated because a hint of negative space gives the smile a suggestion of depth. No corridor at all gives a grin which is toothy, flat, and too full. Too much corridor and your smile ends up being too narrow.

Can I choose the colour, form, and shape of my teeth?

Yes, you can. The patient’s own remarks are essential. Most people like to choose the colour of their new teeth. Some people say, ‘I had all my live small teeth, so can you make them look similar?’ This is no problem. On the contrary, personal touches should be encouraged. And so, this is a matter of effective communication between the patient, the clinician, and the laboratory. Photographs of yourself from before, smiling, or showing teeth can be important, so you are encouraged to bring them with you. The basic condition is that teeth should match the face. And, of course, we need to follow the tooth proportion guidelines. The shape, form, volume, and colour of the teeth should match your face. The basis for all this is nature’s golden proportion. For a certain width of a tooth there is a certain height. However, speaking personally, I love the interaction between the patient, the surgeon, and the laboratory in these decisions.

What about speech problems with a fixed prosthesis?

That’s an important point. Some dentists still advise their patients to go for a conventional prosthesis or an overdenture on two to four implants (the Dutch way, in a manner of speaking, for some reason or another). They are concerned about lisping and uncontrolled air escape, which certainly can be very irritating and unpleasant. In particular, the dento-alveolar sounds with an explosive burst, i.e. the letters d, t, and s are notorious for lisping. Words like ‘sixty six’ or ‘Missisipi’. As always, remember that there are professional solutions for everything. Indeed, in earlier fixed prosthesis designs there was still some space between the construction and the gum tissue (for cleaning purposes). Of course, a flange in a conventional prosthesis seals off this space, but this, to me, seems to be a simplistic and archaic solution. Quite simply, those days have gone. Just remember the fact that some clinicians found a lot of complaints of lisping in their research, whilst others found hardly any difficulties in speech. This suggests at least that treatment protocol might affect the outcome of the treatment delivered. And so, here we give some guidelines and considerations that help Dr Defrancq to overcome speech problems.

First of all, the space must be sealed off in a fixed prosthesis in order to allow for correct pronunciation. And so, intimate tissue contact is required between the gum and the structure. The idea that this facilitates dental hygiene and cleaning is simply incorrect.
Furthermore, the arch width of the fixed prosthesis is of paramount importance. The space between the lingual left and lingual right side of the arch should be comfortable and spacious enough for the tongue.
At the front, too, the central incisors should emerge smoothly, fluently and naturally from the palatal gum area, and not abruptly. Otherwise, the tip of the tongue has no natural flow to create sounds.
Most important is the understanding of the notion of ‘free space’ during speech. When you are relaxed, but also during speech, the upper teeth should not touch the lower teeth at all. This fault is easily detected by listening to a person pronounce the word ‘Mississippi’. With the s sound, the mandible moves to the most forward and upward (closed) position it ever assumes during speech. This spacial position is repetitive and recordable to within 1mm of accuracy. The bottom line here is simple and correct: The teeth should never come into contact with each other during speech. If they do, you have a speech problem. This consideration is vitally important if your natural dentition is a deep bite at the front. You should make a careful study of your free space.

Dr Defrancq, where do you get the bone graft from and why?

The posterior hip graft

The first source of bone is the hip, mostly the posterior hip. The posterior hip has the largest quantity of bone which can be reaped (2.4 times more than the anterior hip graft). This area heals very well, with minor pain and low morbidity. On the next day, patients walk out of the hospital without any support at all. They are able to drive a car. The cancellous part of the graft is milled and condensed. We make one volume of reaped bone from the four volumes. This means that more stem cells are transferred to the jaw, so that more new bone can grow faster. This is by far the best method in cases involving young people with an atrophy of the upper jaw, and where a considerable amount of bone is needed for the rehabilitation. The ultimate reason for choosing this particular graft is facial aesthetics. The aim is not to augment the crest vertically, but vestibularly (the outer side). We want the implants to be placed directly in the axis of the final teeth position without a ‘plateau’ for the teeth or a perimeter too small for the bridge construction. This means comfort and this also impacts the aesthetics.

The anterior hip graft

The anterior hip graft is a source as well, in cases where less bone is needed or only on one side.

The cranial bone graft

The cranial bone graft is a source of bone graft as well, and Dr Defrancq uses it particularly for patients suffering from low back pain or in areas of the mouth where there is a lot of cicatrisation and contracture. Cranial bone, once transplanted is nothing more than a transfer of hydroxylapatite. Not one cell survives the transfer, but the advantage is that cranial bone is re-vascularised quickly. This bone is not very malleable and often creates ridge irregularities and fluffing of tissues. Therefore, it is not our first choice.

Small bone graft

In more exceptional cases, bone is taken from the chin area or from around the wisdom teeth. Alveolar bones, i.e. the bones immediately around the extracted teeth, extracted, are also used frequently. It is often necessary to trim or level this bone. This bone is then chipped and crushed after it has been cleaned and washed thoroughly.

Artificial bone

Often, practically always, we use also artificial bone. This artificial bone is added to and mixed with the bone graft. Often, we use the artificial bone as a solitary graft material, if not much bone is needed. This happens every day! But remember two things:

When large quantities are used, there is a much greater risk of infection and losing everything.
It takes 7-8 months before artificial bone becomes living jaw bone, and that’s twice the time it takes if your own grafted bone is used.

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