Dr. Rui Vidal Salgado

Dentist

Bone regeneration with titanium mesh 

The future of implantology

HPA Magazine 19

Whenever a tooth is lost, the bone that was supporting it reduces in volume, which might condition the placement of an implant. The alveolar process also called the alveolar bone, is a thick ridge of bone that supports the tooth. Tooth extraction conditions alveolar bone resorption. This resorption is, in a first phase, fundamentally horizontal in the direction of the tongue or palate. Over time, a vertical resorption of the alveolar process is observed. However, trauma or exuberant infectious of teeth or  implants can also result in loss of volume in the crest of the alveolar.

Dental implants are routine therapeutic options in oral rehabilitation, restoring comfort and quality of life to patients with one or more missing teeth (partial or total edentulism). In some cases it is possible to install implants in the remaining residual bone for functional and aesthetic rehabilitation. In other cases, atrophy of the alveolar process results in insufficient bone for implant placement. Therefore, among other necessary conditions for dental implant treatment to be successful, is to make sure that residual bone volume (quantity and quality) exists. The final bone structure is a key factor for long-term success, ensuring the aesthetics and function of implant placement surgery. The presence of insufficient bone volume negatively affects the prognosis and long-term survival of implants.
The lack of residual bone volume can result in horizontal, vertical defects or both, conditioning the procedures which are necessary for guided bone regeneration (GBR), the objective being to restore the anatomy of the alveolar process/physiological ridge as much as possible to allow a more natural and functional rehabilitation.
The GBR technique consists of stabilizing and isolating a clot as well as the defect to be regenerated so that osteogenic cells intervene in bone neoformation. 
Primary wound closure, angiogenesis, maintaining space and clot stabilization are the biological principles of this technique. The objective is the mechanical protection of the blood clot, the delimitation of the bone defect, using a physical barrier/membrane to facilitate the migration and proliferation of osteogenic (bone-forming) cells and preventing, during the process, the colonization of the defect by non-osseous tissue, namely epithelial cells and fibroblasts. 
The biological basis of this technique is based on guided periodontal tissue regeneration, first described by Neyman in 1980.
All techniques for restoring adequate and enough bone, with an emphasis on vertical defects, are very sensitive and highly specific procedures. 
Several techniques are proposed with the aim of recovering bone defects, replacing the anatomy of the alveolar ridge. A piece of bone can be collected from, for example the lower jaw or pelvic crest and modelled to adapt to the area with the bone defect. 
Other medical products can be used, such as membranes of various types (characterized by biocompatibility, capacity for tissue integration, maintenance of space for a sufficient period, promoting cell selectivity, with the possibility of clinical handling, providing an effective barrier without risk of complications) and different bone replacement materials. 
As far as the graft material is concerned, the combination of autogenous bone with xenograft, with the aim of associating the structural properties of the biomaterial with osteogenic and osteoinductive potential of the autograft (autogenous - material obtained from the patient himself with osteogenic, osteoconductive and osteoinductive properties; xenograft - material obtained from other species with osteoconductive capacity). 
The membranes that function as a barrier are divided into two categories: absorbable (collagen) and non-resorbable, membranes in polytetrafluoroethylene (PTFE, PTFE-d/high density, e-PTFE/expandable, with or without titanium reinforcement) or titanium (preformed or customized).
 

The success and survival percentage rate of these implants is similar to those placed in native bone as well as to those of other bone regeneration techniques, which are used for patients with atrophic ridges. Currently, GBR represents the gold standard for correct implant-prosthesis rehabilitation permitting sufficient bone volume to be obtained.
Based on existing scientific literature, it is possible to confirm that the use of a titanium membrane (preformed and customized) in combination with autogenous bone replacement particle grafts and xenograft, represent a safe and predictable technique for vertical and / or horizontal bone volume augmentation in cases of patients with few or no teeth, in the treatment of small, medium and large defects. 
Bone regeneration with a customized titanium membrane, with adequate soft tissue management, careful preparation and patient selection currently make this technique the gold standard in regenerative oral rehabilitation surgery.
The customized titanium mesh (CAD-CAM technology) can be used for different types of interventions such as:
> Alveolar bone regeneration either before, simultaneously or after the installation of implants (implant bone regeneration to recover defects resulting from periodontal disease, missing teeth or systemic diseases);
> Restoration of a bone defect to balance facial symmetry in patients who have suffered trauma or extensive surgery (trauma or tumour ablation resulting in the absence of bone with different defects such as, for example, on the mandible, infra-orbital region, etc.);
> Restoration of fractured bones in the reduction of complex comminuted mandibular fractures.

At PRO HPA/Dental HPA, we are one of the pioneers in bone regeneration with a titanium membrane customized to the patient's bone defect, which allows vertical (up to 7mm) and horizontal (up to 5mm) bone augmentation in a predictable, safe and consistent way. It also provides adequate maintenance of space, which is a fundamental prerequisite for any bone regeneration procedure, with a low exposure rate, as it is perforated and allows adequate vascularization of surrounding tissue, easy installation without the need for intraoperative adaptation, resulting in a simpler and quicker surgery. In terms of time and equipment, a conventional membrane requires an average of 111.9 min (+/- 11.6) to install while custom-made devices require 75.28 min (+/- 18.5) and 1.31 screws ( +/- 0.48) compared to 3.23 (+/- 0.73) in the same order, thus reducing the risk of contamination of the membrane and the graft, eliminating the need for cutting and adaptation procedures that sometimes leave sharp edges that cause irritation and dehiscence of the mucosa and undesirable early exposure of the membrane. This set of advantages will allow for an even better postoperative period, due to the shorter surgical time and guaranteed stability of the membrane, fundamental for graft immobilization and success.
Producing a customized titanium membrane uses CAD-CAM technology. Based on a Cone Beam CT Scan (CBCT) image of the bone defect located in the oral cavity and a digital work flow system, it is possible to create customized titanium meshes that adapt perfectly to the bone defect of the site to be regenerated for the installation of the dental implant

CASE STUDY

The images of a surgery performed at the PRO HPA/Dental HPA with a personalized titanium membrane, in a patient who came to us to rehabilitate the installation failure of two premolar implants (Image 1) with consequent bone loss, where bone volume gain can be seen. Once the two implants had been removed and once the remaining bone had healed, preoperative study was carried out with Cone Beam CT Scan (CBCT) imaging (Images 2 and 3) to create the personalized membrane (Image 8). It is important to note the bone increase in images (4,5,6 and 7) 6 months after the surgery. Thus, a vertical gain of 4mm and a horizontal gain of 4.3m was obtained, in addition to a correct anatomical contour.