Reduction of the bone dimensions after tooth loss leads to complications during dental implant placement and prosthetic rehabilitation of the patient. Ridge augmentation procedures aim to increase the available bone volume and provide adequate surface area for the following treatment. Different methods and materials are suggested for the purposes of guided bone regeneration. This case report represents the management of a severe bone atrophy with a 3D printed titanium mesh.

3D printing, bone graft, ridge augmentation, titanium mesh

Alveolar ridge deficiencies present a hurdle for prosthetically driven implant placement. Nowadays, the decreased levels of available bone can be overcome with different regeneration procedures including bone blocks, distraction osteogenesis or guided bone regeneration carried out with the use of different membranes.^[1] One of the latest additions to the arsenal of digitally driven dentistry is the use of 3D printers for the creation of custom-designed titanium lattice structures which act as a graft stabilization device over the course of the healing period.^[2] The benefits of these medical appliances include ease of use, predictability in terms of augmentation volume and shortened surgical procedure.

A 51-year-old female came to the Research Institute of the Medical University of Plovdiv with the chief complaint of chewing difficulty on her left side due to loss of inferior second premolar and the two molars. The extractions happened a while back (the patient could not remember when exactly) and no precautions were taken to preserve the dimensions of the alveolar ridge, hence the available bone in area was lacking in height and width (Fig. 1) .

Figure 1.

Horizontal and vertical dimensions of regions of interest in posterior mandible.

The presented cone beam computed tomography (CBCT) shows that the height of the alveolar ridge is only suitable for placing short dental implants; however, the width, though it may seem adequate, would not allow for prosthetically driven implant placement. For those reasons, we decided to treat the patient with vertical and horizontal guided bone regeneration (GBR) and delayed implant placement.

This case was part of a larger patient sample size involving a variety of bone deficient sites. The treatment of those patients was randomized (using the simple randomization method) in two groups, so GBR on one was done with the gold standard – titanium reinforced PTFE, and on the other – with custom 3D printed titanium mesh. The case we describe in the present article fell in the latter category. DICOM files obtained from the CBCT scans were sent to a company which specialized in printing titanium medical appliances (Biotec srl) and specific instructions were given with regards to the desired dimensions of the future alveolar ridge (Fig. 2) .

Figure 2.

DICOM files used to build a STL image of the site, which is virtually augmented and, lastly, a Ti mesh is designed over the augmented volume.

As can be observed from the presented image, the mesh is designed in such a way that it does not impinge on adjacent vital structures – in this case, the mental foramen and the nerve emerging from it. A small side note, which will be important later – in the “blueprint” of the titanium framework, weaker spots are left on the occlusal side of the mesh, which aids its removal after the healing period (Fig. 3) .

Figure 3.

Buccal and lingual plate of the mesh are connected only by three small “bridges”.

Surgical case management

After the patient is anesthetized, a buccal and lingual mucoperiosteal flaps are created for adequate access to the surgical site to be obtained. The incision design aims to create the so called “asymmetrical flap” by making a crestal incision, which buccally is extended two teeth away, and lingually – only one tooth away from the defect site and both sulcular incision ending with a vertical releasing incision. A crucial aspect of any GBR procedure is the flap mobilization, and for the buccal flap, it was a simple periosteal releasing incision. As for the lingual flap – it was divided in three zones, which corresponded to the mobilization technique used for the release (Figs 4a, 4b, 4c) . ^[3]

Figure 4.

a) retromolar area; b) mylohyoid area; c) premolar area.

The soft tissues in the retromolar area were only elevated from their bony foundation (Fig. 4a) , whereas the tissue in mylohyoid zone (Fig. 4b) the superficial fibers of the eponymous muscle were dissected in a blunt fashion. Lastly, the lingual flap in the premolar area (Fig. 4c) was mobilized by a periosteal releasing incision due to the oblique pathway of the mylohyoid muscle. These actions gave the lingual flap almost a three-fold increase (Fig. 5) .

Figure 5.

Total mobilization of lingual flap.

The rest of the procedure involved fenestration of the cortical bone of the accepting region to promote vascularization for the future bone regeneration. Bony graft was loaded on the printed titanium mesh, placed over the atrophic ridge, and fixed with screws and lastly the flaps over the metallic superstructure were sutured in bilayered manner.

After an uneventful healing time of seven months, a CBCT image showed the results of the successfully regenerated bone (Fig. 6) .

Figure 6.

Vertical and horizontal dimensions of regenerated bone.

The site was uncovered and for ease of mesh removal its buccal and lingual plate were separated by cutting the “weak spots” on the occlusal surface of the titanium structure. The “pseudoperiosteum” was removed from the newly regenerated tissue and implants were placed in the designated sites (Fig. 7) .

Figure 7.

Implant placement in regenerated bony tissue.

Alveolar ridge deficiencies have prevented clinicians from offering their partially or fully edentulous patients fixed prosthetic solutions due to the tremendous skillset required to use a conventional membrane for graft stabilization. Because of the physical properties of the titanium mesh and the fact that it is specifically designed this is no longer the case. Surgical time is dramatically decreased since there is no need for the clinician to cut, shape and carefully position the membrane to the desired place. What is more, the rigidity of the medical device eliminates the need to use numerous fixation screws to optimize graft stability, which decreases accidental perforation of adjacent anatomical structures. Another advantageous feature is the microporosity of the meshes structure, which dramatically increases the graft’s vascularization by opening the way to the blood vessels in the periosteum. With those remarks in mind, the practitioner only has to take time in careful mobilization of the buccal and, in mandibular cases, the lingual flap.

However, some of the features of the titanium mesh are not without its opponents. Because of the rugged structure of the metal’s surface, it has been stated that this could be a reason for flap dehiscence – the most notable culprit for negative results after GBR.^[4] It has also been noted that the macroporosity of the lattice structure is not capable of keeping the non-bony cells out of the graft’s surface, thereby causing the most superficial layer to turn into connective tissue known as “pseudoperiosteum”^[5], which does not provide any crestal stability for dental implant placement. Some authors say that this tissue has protective properties in case of graft exposure; however, our experience shows that the benign capabilities of this tissue are minimal. Recently is has been stated that this tissue could be used as an “epithelial graft” for the increase of the width of keratinized gingiva around dental implant placed in such areas.^[6] This kind of “graftless” surgery, however, is yet to reveal its long-term prospects for widespread use.

The benefit of the titanium mesh in terms of increased vascularization was recently implemented in the creation of a titanium reinforced PTFE mesh, which has openings on the occlusal side on the product only. The macroporosity of those medical devices gives the practitioner the ability to utilize BMPs osteoinductive properties alongside with their bone graft, since the morphogenic proteins work only if there are mesenchymal cells nearby, in this kind of procedure – from the periosteum.^[7] As is with any appliance in the medical field, the custom-made titanium mesh has both advantages and drawbacks. However, because of the recent popularization of the product, we have yet to observe the long-term results from the application of this modern and innovative product in the field of tissue regeneration.

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The authors have no funding to report.

The authors have declared that no competing interests exist.