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SINUS LIFT OR SINUS FILLING

OUR SOLUTIONS IN PRE-IMPLANT SURGERY
IMPLANT-SUPPORTED BRIDGES IN MCI "ALL ON

THE SINUS LIFT INCREASES THE RESIDUAL BONE HEIGHT
AVAILABLE UNDER THE SINUS INSUFFICIENT TO PLACE ONE OR
SEVERAL DENTAL IMPLANTS TO REPLACE
UPPER MOLARS AND PREMOLARS

OUR SOLUTIONS IN PRE-IMPLANT SURGERY FOR THE PLACEMENT OF
IMPLANT-SUPPORTED BRIDGES IN MCI "ALL ON
THE SOLUTION OF SINUS FILLING (SINUS LIFT)

THE "SINUS LIFT" TECHNIQUE OR INTRA SINUS BONE GRAFT

Also called “sinus lift” or “partial sinus filling“, this intra-sinus bone graft is performed to manage a lack of bone after a tooth extraction. By definition, it is performed exclusively in the upper jaw in the sinus cavity in the posterior sectors of the upper jaw.

This intra-sinus bone graft consists of raising the level of the sinus floor from a few millimeters to almost two centimeters. This elevation of the sinus floor is obtained by partially filling the bottom of the sinus cavity by inserting a bone graft between the lower cortical bone of the sinus, above the basal bone of the maxilla, and the mucous membrane that lines the inner wall of this same cortical bone. This mucous membrane covers all the partitions of the sinus and forms the Schneider’s membrane. It is as fragile as “wet toilet paper”. It is therefore very difficult to raise it without perforating it. However, this is the main operation of the sinus lift.

There are two approaches to access the maxillary sinus:

  • The crestal route on the top of the alveolar bone ridge. This technique described by Dr. Summers and which bears his name is reserved for simple cases of bone augmentation.
  • The lateral approach through an opening in the bony septum of the sinus at the foot of the zygomatic bone (malar or cheekbone) was described by Drs. Caldwell and Luc and bears their names. It is most commonly indicated for large-scale bone grafts. It is preferable to perform this type of intrasinus bone graft in a dedicated surgical area or better in a clinic operating room.

In implantology, the sinus lift is proposed to the maxillary edentulous patient, when the residual bone height available under the sinus is not sufficient to place one or more dental implants to replace the upper molars and premolars.

A minimum of ten millimeters of bone height in the axis of the implant and at least two millimeters all around the dental implant are required to hope for a good osseointegration of the implant in the bone.

Of course, good vascularization of the grafted bone is crucial for the healing of the graft. In this sense, the contribution of bone growth factors contained in Plasma Rich Platelet (PRP) and Plasma Rich Fibrin (PRF) is a new paradigm in implantology.

An alternative solution to the lack of available bone volume is the placement of short dental implants or mini implants. It takes between six and seven millimeters of subcrestal height to be able to insert these short or mini implants. The short and medium term results seem to be excellent although we do not have a lot of experience with this type of dental implant. However, short dental implants have the disadvantage of not having a safety margin if peri-implantitis occurs.

The height of the residual bone crest must be greater than or equal to the length of the dental implants, i.e. at least 6 mm, which may not be the case even with mini dental implants.

The maxillary sinuses are part of the paranasal sinuses. They are air cavities (filled with air) where the air inlet is the same as the outlet. They are connected to the nasal cavity by channels/orifices called ostio-infundibular complex. The infundibular canal in its normal variant leads the main mucosal drainage to the nasal cavity. It is located at the apex of the sinus medial wall in the infundibular region and terminates at the middle meats, bilaterally, below the middle turbinates. This permeability helps to avoid containment sinusitis. A middle meatotomy by an ENT surgeon is indicated in case of ostial obstruction prior to any intrasinus graft in order to avoid maceration of the sinus bone graft.

The paranasal sinuses are contained within the cranial bones and divided into four groups:

  • The frontal sinus above the nose and eyes is located in the frontal bone;
  • The ethmoidal sinuses, composed of 10 to 20 alveoli, are located between the nasal cavity and the eye sockets within the ethmoid bone;
  • The sphenoidal sinus is located in the sphenoid bone at the center of the skull base;
  • The maxillary sinuses are located under both orbits. These two hollow cavities (or pneumatic cavity) are located between the zygomatic bone (or cheekbone) in front, the maxillary bone in its basal part below and the floor of the eye socket above. The sinus is located above the upper molars and even the upper second premolar. Its inner walls are lined by a mucous layer, which is called “Schneider’s membrane”.

The roots of the upper molars are connected to the maxillary sinus cavity and its floor cortical:

  • Either, they are located below the bony cortex of the lower sinus wall;
  • Either, they are located against the sinus floor formed by the bony cortex of the lower sinus wall;
  • Either, they penetrate inside the sinus cavity. The roots of the molars and premolars are wrapped in a thin bony lamina of cortical bone attached to the desmodont internally and covered by Schneider’s membrane externally, creating more or less deep digitations.

The frequent consequence of the latter anatomical situation is the systematic creation of an oral-sinusal communication (OSC) at the time of molar extraction.

Even if there is no MBC, bone resorption is present in both directions in the vertical axis: alveolar bone around extracted teeth normally resorbs from the alveolar ridge to the sinus, but also from the sinuses to the alveolar ridges due to air pressure in the sinus. The aerial cavity “swells” under the effect of the pneumatic pressure and in the absence of bony or dental obstacles. This invariably results in a descent of the sinus floor.

The air that constantly circulates in the sinus cavities maintains a phenomenon of air pressure or pneumatization that increases the size of the sinuses after a tooth extraction.

The height of the bone between the alveolar ridge and the sinus floor can be reduced to almost nothing once resorption has reached its maximum. It is therefore impossible to place dental implants on an upper jaw that is atrophied in its posterior part. The volume of bone is insufficient for this surgical technique.

What is the purpose of the sinus filling operation?

Below,photo 1 shows a lateral view of the upper jaw after extraction of the upper first molar. The bone is resorbed at this tooth extraction site. The placement of a dental implant is indicated. However, this placement requires a bone graft in the lower sinus to obtain a minimum height of bone so that the dental implant does not perforate the maxillary sinus.

Photo 2 shows the result of the maxillary sinus filling: The sinus floor level is raised by the length of the implant, i.e. the length of a normal root, thanks to a biomaterial graft placed under the Schneider’s membrane once it has been reclined.

sinus lift greffes osseuses - comblement de sinus - greffe pré-implantaire

WHAT ARE THE OPERATING TECHNIQUES
TO PERFORM A SINUS LIFT?

The choice of surgical technique to perform a bone graft by lifting the sinus floor depends primarily on the volume of graft required to place the implant(s).

Two techniques are available: the crestal approach and the lateral approach:

  • In cases of large reconstruction of the sub-sinus area, lateral access is preferred.
  • In cases of small reconstruction of the sub-sinus area, crestal access is preferred.

Prior to surgery, a fine exploratory examination of the sinus cavities must be performed: a panoramic scan will be prescribed, completed by a three-dimensional 3D examination with a CBCT cone beam scanner.

This examination allows us to accurately measure the height and width of the sinus cavity and to identify obstacles such as walls or septa as well as possible contraindications such as sinus pathologies.

sinus lift greffes osseuses - comblement de sinus - greffe pré-implantaire

The traditional sinus lift technique with a lateral approach

Also called the Caldwell and Luc bone fenestration technique. The first sinus lift procedure was performed by Dr. O. H. Tatum in February 1976 in Alabama. It allowed the placement of two endosseous implants. Since then, many developments have perfected this technique, the first being that of Boyne in 1980.

This protocol is indicated when it is necessary to graft a large volume of bone. in general, the residual height of bone under the sinus is between almost nothing and 6 millimeters

The dental surgeon creates an access flap to the external bony wall of the sinus by peeling off a gingival flap.

Then an endobuccal access route is created by grinding the bone of the external lateral wall of the maxillary sinus to obtain a large access and an excellent visibility of the area to be operated.

Schneider’s intrasinusal membrane is exposed. It is removed very gently so as not to perforate it. This Schneider’s membrane is lifted and reclined upwards on all the walls of the sinus. This surgical technique aims to form a pocket in the lower part of the sinus that will be filled by the bone graft.

Figures in the scholarly literature vary but it can be estimated that the risk of Schneider’s membrane injury is around 60%. It can be repaired extemporaneously during surgery with aPRF membranes and/or a collagen membrane.

The long-term success rate is estimated at 94%.

Minimally invasive sinus lift technique using a crestal approach

Summers’ technique. This is a less invasive technique than the lateral approach technique.

Crestal access is indicated in cases of low-volume grafting and for a maximum height increase of less than 2 to 4 millimeters. The residual bone thickness must be greater than 6 mm.

The dental surgeon approaches the sinus floor through the alveolar ridge by making the drilling hole for the dental implant, at the level of the teeth and in the same axis. The drilling of the dental implant space goes to the floor of the sinus. Then, the intrasinus bone graft is pushed into the sinus through the drilling hole of the future implant, using osteotomes and a hammer that fractures and pushes the sinus floor and the membrane that lines it.

The increase in bone height is generally less than with the lateral approach technique, but it is sufficient when the residual bone height is already significant.

This protocol involves placing the dental implant at the same time as the graft, during the same procedure.

The Summers technique has two advantages: it is simple to perform for the dentist, and it is minimally invasive for the patient. The postoperative effects are minimal.

It is reserved for the placement of one or two implants and does not concern total reconstruction.

However, it also has disadvantages: it is a delicate protocol, as it is performed blindly. Because Schneider’s membrane is fragile, there is a risk of perforation, which can lead to serious infectious complications that may require lateral access to repair the damage.

chirurgie osseuse pré-implantaire greffes pré-implantaires greffes osseuses implant dentaire
THE ANTHOLOGY OF OUR CLINICAL CASES

YOU ARE UNIQUE!

CLINICAL CASES OF MAXILLARY BONE RESECTION
CLINICAL RESULT OF THE SINUS LIFT

INITIAL SITUATION VS. CLINICAL OUTCOME

The different grafts used for the sinus lift

THE AUTOGENOUS BONE GRAFT USED FOR SINUS LIFT WITH HARVESTING

Bone autografting with bone graft harvesting from the donor and recipient patient has long been the “golden standard” in pre-implant surgery. The advent of biomaterials and autologous platelet concentrate blood transplants has made this statement more relative, although this concept remains relevant in certain complex clinical cases.

A scalp incision is made in the parietal region. The bone of the skull vault is uncovered and a piece of the external cortical layer and the diploea (spongy bone between the two flat bony plates constituting the cranial cavity) is removed. The inner layer of the cranial cortical bone is respected. A cortical lamella will constitute the ceiling of the graft. The other part is reduced to bone powder which will be used to fill the lodge. The parietal bone is of the same embryological mesenchymal origin as the maxillary bone, which gives it a better compatibility. This removal is painless and without apparent scarring, except in cases of pronounced baldness.

The disadvantages are a mandatory hospitalization and a risk of accidental perforation of the deep cortex of the skull and a risk of cranial hematoma. In addition, bone fragility at the level of the specimen increases the risk of cranial trauma in case of impact.

The incision is located at the level of the crest of the hip bone (at the level of the head of the hip). The removal of the head of the iliac bone is performed with osteotomes.

This procedure leaves a scar and pain that can affect walking for several months to a year. The bone at this level is cortico-spongy. It is a bone which, in the sinus, resorbs little. But adipocytes (fat cells) contained in the marrow can form fat vacuoles that are unsuitable for the placement of a dental implant and its osseointegration. Hospitalization is mandatory.

The disadvantages are a risk of hematoma or abscess at the donor site as well as chronic hip pain or sensitivity problems in the thigh.

The donor areas are the chin and ramus. The ramus area is the outer surface of the start of the vertical branch of the mandible, behind the wisdom teeth. The sampling is simpler than the two previous ones, but only gives a small quantity of cortico-spongy bone. For a sinus lift between 1 cc and 4 cc of bone is consumed, therefore the indication for this donor site is low, unless this autogenous graft is mixed with other biomaterials such as an allogeneic or xenogeneic.

The disadvantages are for both sites a risk of hematoma or abscess.

For the chin area: a risk of hypoesthesia of the incisors and canines, or even a total loss of sensitivity in these teeth.

For the ramic area: a risk of disturbance of the sensitivity of the lower lip on the operated side which can be a few weeks or definitive. There is a risk of fracture of the mandible during the operation or following an impact, because of the bone notch made which weakens the lower jaw.

choix-greffons-greffe-osseuse
Play Video
THE FILM the "SINUS LIFt with autogenous cranial bone graft".

Bone grafting for sinus filling using cranial parietal bone harvesting

BONE GRAFTS WITHOUT HARVESTING THANKS TO BIOMATERIALS

Biomaterial grafts in combination with PRP and PRF are now preferred over autogenous harvesting.

The advantage is that there is no donor site and therefore a second operation to manage. The amount of graft is by definition unlimited.

The disadvantage is a graft that is not as osteoinductive and osteoconductive as autogenous bone. But this disadvantage is disappearing thanks to the new generations of biomaterials, which are much better constructed and give an osteoconductive framework close to human bone, especially when the graft is allogenic (i.e. of human origin). See the chapter on bone graft selection. Click here

The addition of PRP and PRF to the recipient site makes the grafts osteoinductive by adding the patient’s own growth factors.

WHAT HAPPENS AFTER THE SINUS LIFT FOR DENTAL IMPLANTS?

The placement of dental implants after the sinus lift is done in one or two surgical steps depending on the volume of bone to be grafted and the quality of the natural bone. It is possible to place the implants in one operation at the time of the sinus lift if the height of the residual bone is greater than 4 millimeters of sufficiently dense bone. If this is not the case or if additional constraints complicate the clinical case, the sinus lift surgery must be dissociated from the implant placement.

The placement of dental implants after the sinus lift is done in one or two surgical steps depending on the volume of bone to be grafted and the quality of the natural bone. It is possible to place the implants in one operation at the time of the sinus lift if the height of the residual bone is greater than 4 millimeters of sufficiently dense bone. If this is not the case or if additional constraints complicate the clinical case, the sinus lift surgery must be dissociated from the implant placement.

Sinus filling and implant placement in two operations

When the residual bone volume is too thin to place a primary fixation of minimal size (less than four millimeters), dental implant placement is performed in a second operation. It usually takes place four to five months after the sinus lift.

sinus lift - bone grafts - sinus filling - pre-implant graft
THE FILM "SINUS LIFt and PRF

Sinus lift" surgery.
the prerequisite for the placement of implants in MCI.
UNDER GENERAL ANESTHESIA.

Play Video

WE ANSWER YOUR QUESTIONS
ON THE SINUS LIFT

The dentist answers your most frequently asked questions. If your clinical case is not listed, please contact him for a consultation.

They are the same for bone grafts with autografts or biomaterials. The main risk is infection of the bone graft.

Two cases can be distinguished:

Either the infectious start is intra-sinusal following a postoperative sinusitis that becomes infected. This is why radiological analysis and identification of a lack of permeability of the infundibular ostium is essential in the case of sinus lift. Indeed, the closure of the ostium leads to the confinement of the graft in the sinus and increases the risk of infection by lack of evacuation of mucous secretions and absence of ventilation.

Either an infection can appear as a result of delayed healing of the gum and a bacterial entry point from the mouth. Suture breakage is often due to chewing pressure on the sutures or overpressure when the patient sleeps on the operated side or puts his hand as a support for his head against his cheek. The postoperative instructions must be scrupulously observed.

The occurrence of infection in the bone graft requires antibiotic treatment. Infection may result in partial or total loss of the graft or its removal during bone curettage of the graft site. The initial treatment plan may be radically changed in this case. The consensus estimate is that 5-10% of the cases are hazardous. However, the risk is greatly increased in patients who smoke or in cases of poor oral hygiene or unbalanced diabetes. Vitamin deficiencies, particularly vitamin D, and high LDL cholesterol are risk factors.

The anamnesis and the preoperative blood tests and 3D radiological tests are of great importance here.

You should not take aspirin or any other antiplatelet or anticoagulant medication within ten days before the procedure, nor should you take dark chocolate or turmeric, which are also antiaggregants.

A strict fast of six hours before the time of surgery must be observed if you are to undergo surgery under sedation in the office or under general anesthesia in the operating room at the clinic. The day before, make a meal with slow sugars and proteins: steak and pasta and drink to hydrate yourself.

You must provide a trusted person to drive you home after surgery. Of course, it is forbidden to drive any vehicle or to take public transportation.

You may be given time off work in case of complications, but you should allow at least one or two days of rest to recover from the procedure.

Get the medication beforehand and also food that is suitable for soft but not mushy eating. Soups, yoghurt, creams and purees are forbidden because they risk entering the wound through the sutures, as well as salads and other plants with seeds (strawberries, raspberries etc.). Food should be able to be swallowed without chewing and without pressure, such as eggs, pasta, rice, oysters etc.

In order to avoid the rupture of the sutures (often due to chewing pressure) it is forbidden to chew on the scar or pull on the cheek to “see” the sutures or to brush the sutures with a toothbrush.

Overpressure when the patient sleeps on the operated side (or puts his hand or elbow against his cheek) causes the sutures to break. The advice is to wear an inflatable collar (airplane type) at night so that you cannot turn over on the operated side and pull on the cheek and the wires.

The postoperative instructions must be scrupulously observed.

There are two types of contraindications:

General contraindications that prohibit a comfort and invasive surgery: acute heart disease, valvulopathy, unbalanced diabetes, severe renal insufficiency, immunodepression, etc. and also an important installed smoking.

Local contraindications such as sinus pathology. A CT scan and ENT examination is routinely requested prior to surgery to ensure that the sinus is free of pathology such as sinus infection, pathological tissue or obliterating sinus.

Post-operative care:

It is essential not to stress the operated area:

  • It is forbidden to blow your nose too hard in order not to traumatize the graft by too much pressure in the sinus,
  • It is forbidden to lie on the operated side in order not to pull on the threads or to open the mouth too much or to chew on the operated site. It is advisable to sleep with an inflatable collar type aircraft to avoid rolling on the side operated.

An edema is inevitable and sometimes a hematoma in the cheek which disappears in about ten days.

Postoperative pain is mainly due to edema. They can be controlled with anti-inflammatory and analgesic drugs.

Antibiotic prescription is essential to prevent infections.

Sometimes blood may leak out of the nose or mouth.

Sometimes small pieces of graft may leak out through the nose or mouth: this is a sign of a bone graft leak that may be minor or major. In this case, the patient must immediately notify the surgeon for a control.

The first major risk is a perforation of Schneider’s membrane which forms a “skin” in the sinus. It is this membrane that the surgeon lifts to slide the graft under. In this case, either the leak is minor and not infected or it is major and/or infected and a curettage procedure must be performed urgently after examination.

The second major risk is the formation of an oral-sinus communication with a fistula and contamination of the graft and sinus.

If the graft closes the unfundibular canal that connects the sinus cavity with the nose and allows its ventilation, then chronic sinusitis can set in with possibly severe symptoms.

Other complications may be related to an operative difficulty such as poor stabilization of the graft, perforation of the antral artery, poor position of the graft to place the implants, formation of fibrous scar tissue, or damage to the suborbital nerve etc.

Healing of the surgical site:

Primary healing is noted for the soft tissues from the first week without complication, the second week allows consolidation and it takes a month for the absorbable sutures to fall out.

Ossification of the graft with PRFs is observed after 3 to 4 months and the implants can be placed at this time.

In some cases, it is possible to place the implants extemporaneously to the sinus lift surgery in order to avoid a second operation.

As with all surgical techniques, it is associated with surgical hazards and possible risks. However, this procedure is known to be reliable and well controlled.