Dental implants: Sinus lift

Sinus lift (or sinus augmentation), is a dentist executed procedure to increase the amount of bone in the molar area of the upper arch in order to prepare it for the insertion of one or more dental implants. The procedure exclusively concerns patients wanting to install implants in this section of the mouth. When there is the loss of the upper molars, the sinus cavity tends to draw nearer to the sinus crest, in time the borders of the cavity can draw so close as to not leave any bone for implant insertion. By “lifting” the membrane covering the sinus cavity , the dentist is able to add bone tissue transplanted into the sinus cavity. After the inserted material has become solid or ready, it is possible to insert the implants since the treated area is fully coherent with the natural bone. In some cases it is possible to insert the implants directly during the sinus lift, but this decision can only be taken by the dentist. The sinus lift procedure represents a safe and predictable method to increase the bone quantity necessary for dental implant insertion.

Sinus lift is the surgical act that adds bone to the upper jaw bone in the molar a premolar area, in order to render it thicker (jaw bone augmentation). The bone is often added between the jaw and the sinus cavities at either side of the nose. In order to make room for the bone, the sinus membrane is lifted.

This intervention is indicated when there is not sufficient bone in the jaw or the sinuses are too close to insert a implant. The reasons fr this condition are many:

1. many people have lost their jaw teeth, above all the rear teeth (molars or premolars), they'd like to insert one or more implants, but there is insufficient bone quantity;

2. due to cranium anatomy, the rear part of the jaw has less bone than the mandible;

3.  the bone has been lost due a periodontal pathology; once tooth loss has occurred, bone re-absorption begins, and if the teeth have been missing for a long period of time, the bone left in often slight;

4. the sinus cavity can be too close to the jaw in order to allow an implant insertion; it must be observed that sinus cavity size varies among individuals, and that it tends to increase in size with age.

The sinus lift is a tested intervention that has been very often applied in the last 15 years and that accompanies the broad success of dental implants. Naturally, only a careful planning carried out by a dentist can avoid complications or risks.

The preparation

In order to carry out sinus lifting there can be the use of either bone tissue originating from the patient's body, or that of synthetic nature, which is more commonly used and can also stimulate the formation of new bone material. The autologous bone is taken from the patient's mouth or from other parts of the body, for example from the leg or the tibia. Before proceeding, the patient undergoes a series of thorough controls to assess the anatomy of his sinuses, its conditions, and the height and width of the current bone.

The procedure

The dentist makes an incision in the gingiva near the molars. The tissue is lifted, exposing the bone in which a small oval gap is opened. The membrane that covers the other gap separates the sinus cavity from the jaw. The membrane is delicately pushed upwards and far from the jaw; the transplant is then carried out in the created space, that takes the place of the sinus cavity. The quantity of bone, autologous or synthetic, is variable even if usually many millimetres of bone tissue are clayed on the jaw. Once the material has been inserted the tissues are stitched shut. The implants will be inserted a few months later, based on the material employed for the graft, or at the same time as the graft if there are the proper anatomic conditions and of implants are used that are capable of stabilisation even with minimal bone quantity available.

• the presence of teeth impairs bone destruction by the sinus cavity 

• the absence of molars allows the sinus cavity to expand itself

• sinus pressure allows it to expand itself into the toothless area, provoking bone atrophy

• the sinus cavity continues to expand itself due to tooth loss, progressively destroying the bone in the area. The teeth of the lower arch traumatise the tissues of the upper ones

• in the space left it is possible to observe bone loss in two different directions.

After the procedure

The operated area almost tends to swell, at times blood loss from the nasal cavities or mouth may occur. The dentist may suggest the use of saline sprays in order to keep the internal nose hydrated, and if needed, prescribe drugs to avoid sneezing, that might push the grafted bone to move and induce undesired spaces. Whoever suffers seasonal allergies will have to programme the intervention in a risk-free yearly period. Usually pain suppressors, antibiotics and an anti-microbe mouth rinse are prescrived in order to prevent any infection or contamination. The majority of patients shows reduced symptoms after the sinus lift; the patient will then return to the dentist a few days later to remove the stitches and control the healing in the treated area. Usually more check-ups take place after the first one, that serve as verification of bone hardening and osteointegration of the grafted material, that is its perfect integration with the rest of the jaw. At this point it is usually possible to insert one or more implants. In some cases, as seen, it is possible to carry out both bone grafting and implant insertion during the same session. This is possible when the initial implant stability is sufficient to ensure a healing of the implants void of any micro-movements, and when the procedure has not presented any special surgical difficulties.

last update: 21 January 2008