Gbr of mandibular atrophic ridges with customized CAD/CAM titanium meshes: A prospective study

OBJECTIVES The aim of this prospective clinical study is to present the preliminary results related to Guided Bone Regeneration (GBR) of mandibular atrophic edentulous ridges with customized CAD/CAM titanium lattice structures (Ti-meshes) in association with particulated au­togenous bone, bovine bone min­eral (in a 1:1 ratio) and the use of a collagen membrane placed over the meshes. MATERIALS AND METHODS In a 2-year period (2018-2019) 15 patients (4 males and 11 fe­males) aged from 43 to 81 years (mean: 62 years; SD: 9.40) presenting with 18 mandibular atrophic edentulous sites, and asking for a fixed, implant-supported restoration, were consecutively enrolled. The atrophy was such to render placement of implants impossible or incompatible with an acceptable implant-supported prosthetic restoration. Treatment consisted of a horizontal and/or vertical GBR procedure employing autogenous bone chips, deproteinized bovine bone mineral particles (DBBM) and a CAD/CAM customized titanium lattice structure (mesh). The mesh was covered with a resorbable collagen membrane. Five to 12 months later (mean: 7.6 months; SD: 1.92), meshes were removed – opening the flap along the previous incisions – and 39 implants were placed in the re­generated areas. After another 3-4 months, implants were re-opened and pros­thetic restorations started. If the quantity of keratinized mucosa surrounding the implants was considered insufficient, epitheli­al-connective tissue grafts were sutures after a vestibuloplasty. The mean follow-up of patients who received the final restorations (10 patients and 27 implants) was 5 months. RESULTS AND CONCLUSIONS An uneventful healing occurred in 16 out of 18 treated sites (88.9%). In 2 sites, an exposure of the mesh occurred 90 days and 120 days after surgery, respectively. One of them was followed by uneventful integration of the grafted bone, with results similar to those of non-exposed sites, while the other was followed by partial bone graft loss but without jeopardy of the final implant-supported prosthetic restoration. Two patients (2 sites) reported transient paraesthesia to the chin area which recovered spontaneously 30 and 60 days later, respectively. The mean bone gain immediately after reconstruction in vertical and horizontal dimensions ranged from 1.60 mm to 8.90 mm, and from 2.14 mm to 9.15 mm, respectively. Six months after the reconstructive procedures, vertical and horizontal dimensions varied from -2 mm to +0.4 mm, and from -0.9 mm to +0.4 mm, respectively. Twenty-seven implants in 10 patients were loaded; one patient and 4 implants were lost to follow-up immediately after the de­livery of the final prosthesis. All remaining implants (23) placed in 9 patients are still in function, thus determining a survival rate of 100%. The mesial marginal bone loss (MBL) per patient ranged from 0 mm to 0,75 mm (mean: 0, 31±0.27 mm); the distal one ranged from 0 mm to 0,63 mm (mean: 0.35±0.26 mm). CLINICAL SIGNIFICANCE Preliminary results seem to demonstrate, despite the short follow-up and the small patient population, that GBR with CAD CAM customized titanium meshes can represent a reliable alternative to other materials used for regeneration of severely atrophic sites, with shortening of operating times and simplification of surgical phases.