Mandibular regeneration: the challenge of posterior atrophy

The management of severe atrophy of the posterior mandibular alveolar ridge represents a major technical challenge in implantology, where combined deficits in height and width often hinder the placement of implants in an optimal prosthetic corridor. This clinical situation requires guided bone regeneration (GBR) solutions capable of maintaining a critical sub-mucosal space in a rigid and stable manner.

This study clinically and radiographically evaluates the efficacy, predictability, and safety of an innovative protocol combining 3D-printed, customized titanium meshes with a "sticky bone" composite graft (a mixture of particulate xenograft and Platelet-Rich Fibrin - PRF). The primary objective is to validate a fully digital workflow, from CBCT planning to custom mesh design, for the simultaneous augmentation of bone volumes during the placement of 16 implants in eight patients (aged 34 to 65 years).

The authors test the hypothesis that a custom-made 3D mesh architecture allows for precise adaptation to the defect (minimizing anatomical deviations) and ensures optimal graft stability. This device aims to achieve significant dimensional augmentation while limiting the classic complications of non-absorbable membranes, such as early exposures or tissue dehiscences.

Methodology: a complete digital workflow for mandibular GBR

This prospective clinical study included 8 patients (3 men, 5 women), aged 34 to 65 years, presenting no systemic contraindications and suffering from severe atrophy of the posterior mandibular alveolar ridge. The protocol was based on a fully digital workflow, starting with CBCT planning for the design and 3D printing of customized titanium meshes (Patient-Specific Mesh).

The surgical procedure was standardized as follows:

• Reflection of a full-thickness flap under anesthesia.
• Simultaneous placement of 16 dental implants in atrophied sites.
• Stabilization of the custom-made titanium mesh to define the volume to be reconstructed.
• Filling of the underlying space with "sticky bone" (a composite mixture of particulate xenograft and platelet-rich fibrin — PRF).
• Hermetic closure using tension-free sutures.

Post-operative follow-up lasted 6 months, including a clinical evaluation of pain (VAS scale) and tissue healing. CBCT radiographic analysis allowed for the quantification of dimensional changes (ridge height and width) by comparing initial data with those at 6 months. The precision of the mesh adaptation was also measured (mean deviation). The meshes were removed at the end of this 6-month period.

Clinical success and implant stability at 6 months

The clinical data reported on this cohort of 8 patients (16 implants) show a 100% survival rate for both the dental implants and the graft at the end of the 6-month follow-up period. Healing proceeded without major incident for all surgical sites.

In terms of safety, the authors note an excellent biological tolerance. Only two cases of minor and transient soft tissue dehiscence were observed, with no exposure of the titanium mesh reported at the end of the 6-month follow-up.

Quantitative analysis of volumetric gains

CBCT radiographic evaluation reveals massive and statistically highly significant dimensional increases (p < 0.001) in both vertical and horizontal planes. The use of "sticky bone" (particulate xenograft + PRF) under the 3D mesh achieved the following results:

Digital workflow precision and adaptation

One of the highlights of this study concerns the accuracy of reproducing the virtual treatment plan in clinical conditions. The adaptation of the customized titanium meshes was judged excellent by the researchers, with extremely low deviation measurements:

• Mean deviation: 0.3371 mm (± 0.1760 mm).
• Stability: Rigid fixation of the mesh allowed maintaining the necessary space for regeneration without compression of the graft.

These results confirm that the combined use of computer-aided design (CAD) and sticky bone achieves high predictability in complex posterior mandibular reconstructions, while simplifying the surgical phase thanks to the passive fit of the framework.

Digital precision and clinical predictability

The results of this study on 8 patients demonstrate that combining a 3D-printed customized titanium mesh with "sticky bone" (xenograft + PRF) achieves major volumetric gains in complex posterior mandibular areas. With an average increase of 155.4% in width and 47.1% in height, the technique provides a solid foundation for simultaneous implantation (16 implants placed), secured by a 100% survival rate at 6 months.

The major asset lies in the accuracy of the digital workflow: the average deviation of only 0.3371 mm between planning and clinical outcome highlights the value of customization. Unlike traditional meshes shaped manually, the 3D mesh eliminates intraoperative handling inaccuracies and reduces surgical time. The two cases of transient dehiscence observed, without final device exposure, serve as a reminder that soft tissue management remains the critical point, although the biocompatibility of 3D titanium appears excellent.

Nevertheless, the scope of these findings must be qualified by the modest sample size and a follow-up limited to 6 months. While initial stability and precision are impressive compared to conventional methods in the literature, the durability of bone volume after mesh removal requires longer-term observations. For the practitioner, these data confirm that the transition to a full digital workflow secures regeneration in cases of severe mandibular atrophy.

Summary of results

This clinical study on 8 patients demonstrates the efficacy of 3D-printed titanium meshes combined with "sticky bone" (xenograft + PRF) for treating severe mandibular atrophies. The 6-month results show 100% implant survival, with an average bone gain of 47.1% in height and 155.4% in width, while maintaining a digital adaptation deviation of less than 0.34 mm.

In concrete terms, for the practitioner:

• Volume reliability: The rigidity of the customized mesh guarantees the maintenance of the space required for regeneration, allowing for massive and simultaneous vertical and horizontal augmentations during implant placement.
• Reduction of exposure risk: The integration of PRF into the bone substitute improves graft handling and soft tissue response, limiting dehiscence (no mesh exposure at 6 months in this cohort).
• Precision and time-saving: The 100% digital workflow eliminates tedious intraoperative manual shaping, ensuring perfect congruence with the recipient site from the moment of insertion.

Technical lexicon of the study

Sticky bone: Composite filling material combining a particulate xenograft and platelet-rich fibrin (Platelet-Rich Fibrin - PRF), used to improve graft stability and handling during ridge augmentation.

Customized 3D printed titanium mesh: Space-maintaining device designed by CAD/CAM and manufactured by 3D printing, whose geometry is specifically adapted to the anatomy of the patient's defect for optimal precision.

Full digital workflow: Process integrating data acquisition by CBCT, virtual surgical planning and additive manufacturing of the prosthetic or surgical device.

Vertical and horizontal augmentation: Surgical reconstruction procedure aimed at simultaneously restoring the height (vertical) and thickness (horizontal) of a resorbed alveolar ridge.

Atrophy of the posterior mandibular alveolar ridge: Severe bone resorption in the area of the lower molars and premolars, limiting the bone volume available for the placement of dental implants.

CBCT (Cone-Beam Computed Tomography): Three-dimensional imaging technique used in this study for digital planning of the augmentation and postoperative radiographic evaluation of dimensional changes.

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