Periosteal elevation in maxilla augmentation.

Rationale:

At the department Cranio-Maxillofacial Surgery of Maastricht University Medical Center (MUMC) the routine procedure for sinus floor elevation prior to dental implant insertion is augmentation with a mixture of autogenous bone and xenogenous bone, which adds morbidity due to the donorsite.
We want to augment the maxillary sinuses without using any substitutes by placing only a resorbable barrier to elevate the Schneiderian membrane of the floor of the sinus. Bone will be regenerated using the periosteal capacity of osteoinduction.



Hypothesis:

In the atrophic maxilla periosteal elevation with a resorbable membrane in the sinuses creates sufficient and reliable bone for later dental implant insertion.



Objective:

To compare the efficacy of two different techniques for the augmentation of the atrophic maxilla.



Study design:

This is a pilot randomized controlled clinical trial.



Study population:

Healthy human edentulous volunteers (18 -75yr old) with bilateral atrophy of the maxilla and insufficiency of the upper dental prosthesis will be included in this study.



Intervention:

This will be a split mouth study design. The sinus will be approached by the lateral window technique. On one side a resorbable barrier will be placed to create a space which will be replaced through newly formed bone. On the contralateral side a mixture of autogenous bone from the anterior iliac crest and xenogenic bone is used to augment the sinus.



Main study parameters/endpoints:

The main study parameter is the difference of the amount of bone formation, measured with a cone beam CT, between the two sides of the maxillary sinuses.

A cone beam CT will be made pre-operative and 4 months post-operative. One last cone beam CT will be produced 4 months after implant insertion.
The bone quality will be evaluated by bone histology, taken at the moment of implant placement.

Other endpoints will be implant survival, prosthetic survival and patient’s satisfaction.



Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

The patient must visit the clinic as often as in a standard treatment. No extra visits are needed.
The benefit of participating in this study is less donor site morbidity, because only half of the amount of autogenous bone is grafted. Second benefit is that the risk related to the use of xenogenous bone substitutes is reduced (slow sinus infections, Creutzfeldt-Jakob disease, etc.).
The risk associated with participation is the presence of insufficient bone in the sinus site with periosteal elevation. In this scenario a second surgery may be needed.

In the atrophic maxilla periosteal elevation with a resorbable membrane in the sinuses creates sufficient and reliable bone for later dental implant insertion.

1. Intake patient; informed consent; permission; CBCT;

2. Sinus floor augmentation in general anaesthesia → split mouth design;

3. 4 months post-op: CBCT;

4. 4-6 months post-op: Bone for histological research; implant insertion;

5. 4 months post-insertion: CBCT;

6. 4-6 months post-insertion: Loading implants
6 months post-loading, Implant stability; prosthetic survival; patient’s satisfaction;

7. 1 year post-loading : Implant stability; prosthetic survival; patient’s satisfaction.

With this study we want to evaluate the bone quantity and quality after periosteal elevation of the Schneiderian membrane. We want to compare these results with sinus augmentation with a mixture of autogenous bone and xenogenous bone. This will be a split mouth design for direct comparison of bone quality and implant survival.



The resorbable membrane that we want to use for the stabilization of the elevated sinus is made of poly(D,L) lactide (PDLLA). This material is common used in the fixation of fractures during trauma surgery. It is a material of great interest because of its proven biocompatibility and high initial mechanical strength and was tested in different clinical studies. PDLLA has the advantage of degradation without generation of any crystalline remnants.

The membrane is 40 x 40 x 0,2 mm and is perforated. When the membrane is heated, it can be formed in the right shape that is suitable to create a stable periosteal elevation in de sinus.