Study context and objectives

The management of horizontal bone deficits in the anterior aesthetic zone represents a clinical challenge where the stability of the grafted volume directly conditions the three-dimensional positioning of the implant. While beta-tricalcium phosphate (β-TCP) constitutes a biocompatible and cost-effective synthetic alternative to bovine-derived substitutes, its rapid resorption kinetics and low mechanical resistance limit its use in monotherapy. This retrospective study, conducted on 61 patients (80 implant sites) between 2020 and 2024, evaluates the effectiveness of a combined protocol associating tenting screws with a composite graft composed of β-TCP, autogenous bone, and concentrated growth factors (CGF).

The specific objective of this research was to evaluate the dimensional stability of horizontal augmentation over an 18-month period using serial CBCT measurements (at 0, 2, and 4 mm from the platform) and to analyze the final aesthetic results. The authors tested the hypothesis that the mechanical support of the tenting screws would compensate for the structural instability of β-TCP, while the addition of CGF and autogenous bone would optimize bioactivity and bone maturation in this critical area.

Study methodology

This retrospective study analyzed data from 61 patients (32 men and 29 women, mean age 37.23 ± 13.28 years) presenting with horizontal bone deficiency in the anterior aesthetic zone. A total of 80 implant sites were included in the analysis between January 2020 and September 2024.

The clinical protocol was structured around the following steps:

• Digital planning: Use of surgical guides for three-dimensional implant positioning after alignment of CBCT data and intra-oral scans.
• "Tenting" technique: Placement of support screws to maintain the regenerative space and define the desired alveolar contour.
• Composite graft: Filling the defect using a mixture combining beta-tricalcium phosphate (β-TCP), autogenous bone (collected during site preparation) and concentrated growth factors (CGF).
• Timeline: The tenting screws were removed 6 months after the procedure, during the aesthetic phase (second surgical stage).

Radiographic follow-up involved serial CBCT examinations (preoperative, immediate, 6, 12, and 18 months). Horizontal bone width was precisely measured at 0, 2, and 4 mm apical to the implant platform. Finally, periodontal and prosthetic aesthetic scores were evaluated at 18 months.

Results: Volumetric stability under mechanical control

Retrospective analysis of 80 implant sites (61 patients) demonstrates a significant increase in horizontal bone width at all measurement levels (0, 2, and 4 mm apically to the platform) compared to preoperative values (P < 0.01). This study highlights three distinct phases in the evolution of the composite graft (β-TCP, autogenous bone, CGF) supported by tenting screws.

Remodelling dynamics and stability

Between the immediate postoperative period and the 6-month examination, no significant difference in bone width was observed (P > 0.05). This result confirms the effectiveness of tenting screws in countering soft tissue pressure and compensating for the early resorption of β-TCP. After screw removal at 6 months, physiological remodeling led to a statistically significant decrease in width at 12 months (P < 0.01), before stabilizing completely between 12 and 18 months (P > 0.05).

Clinical and aesthetic observations

In terms of quality and safety, the authors report the following data:

• Complications: No tenting screw exposure was recorded during the 18-month follow-up.
• Soft tissues: Mucosal translucency at the screw head level was noted in 2 patients with a thin gingival phenotype, with no impact on therapeutic success.
• Aesthetics: Aesthetic scores (Pink and White Esthetic Scores) at 18 months were judged satisfactory for the entire cohort.

These numerical data indicate that the combination of β-TCP with tenting screws and growth factors allows for predictable horizontal reconstruction in the aesthetic sector, despite the rapid degradation kinetics inherent to tricalcium phosphate alone.

Clinical analysis of results

The results of this retrospective study of 61 patients (80 sites) demonstrate that the use of tenting screws overcomes the main limitation of β-TCP in the aesthetic zone: its low mechanical strength and rapid resorption. The maintenance of bone volume between the immediate postoperative period and the 6-month follow-up is clinically significant (p > 0.05), proving that the screws ensure graft stability during the critical initial healing phase.

The moderate reduction in bone width observed between 6 and 12 months (p < 0.01) coincides with the removal of the screws and the functional remodeling of the grafted site. However, the stabilization of measurements between 12 and 18 months suggests a long-term integration of the synthetic substitute when potentiated by autogenous bone and CGFs. From an aesthetic perspective, the absence of screw exposure and the satisfactory PES/WES scores validate the safety of the protocol, although the mucosal translucency noted in two patients with a thin phenotype highlights the need for rigorous soft tissue management.

Limits and perspectives

The study presents inherent limitations due to its retrospective and single-center design. Although the sample size is robust for the anterior zone, the 18-month follow-up remains medium-term. Furthermore, the specific influence of each component (CGF vs. autogenous bone) on the success of the β-TCP composite was not isolated, as success here relied on a systematic combined approach.

Implications for practice

For the practitioner, this protocol offers an economically viable alternative to bovine-derived bone substitutes (DBBM). The integration of the digital workflow for implant positioning, coupled with the placement of tenting screws, allows for the use of β-TCP with increased predictability, even in cases of marked horizontal deficiencies in the aesthetic zone.

Study summary: Horizontal augmentation using "tenting" screws and β-TCP

This retrospective study conducted on 61 patients (80 implant sites) demonstrates that the use of "tenting" screws combined with a β-TCP composite, autogenous bone, and CGF allows for stable horizontal bone augmentation in the aesthetic zone. CBCT results at 18 months confirm the stability of the grafted volume during the first 6 months thanks to mechanical space maintenance, followed by minor and stabilized remodeling after screw removal (p < 0.01).

In concrete terms, for the practitioner:

• Secure the volume: Use "tenting" screws during augmentations with β-TCP alone; their mechanical support compensates for the rapid resorption of the material and prevents early collapse of the site before bone maturation.
• Optimize the graft: Do not discard your drilling debris. Collect autogenous bone during implant preparation and cortical perforation to combine it with β-TCP and CGF, thereby increasing the bioactivity of the synthetic scaffold.
• Manage remodeling: Anticipate a slight decrease in ridge width between 6 and 12 months (following screw removal), while knowing that the volume stabilizes long-term after the first year.

Technical lexicon of the study

β-TCP (Beta-Tricalcium Phosphate): Synthetic, osteoconductive, and biodegradable bone substitute. The study highlights its logistical and economic advantages, notably stable availability and relatively low cost, while specifying that its resorption rate requires rigorous space management.

Tenting screws: Devices providing passive mechanical support within the bone defect. They are essential in this protocol to maintain the regeneration volume and prevent soft tissue collapse onto the β-TCP graft, which is less resistant to compression than bovine materials.

CGF (Concentrated Growth Factors): Growth factor concentrates extracted by centrifugation of the patient's autologous blood. They serve here as a biological catalyst, mixed with β-TCP to improve local osteogenic activity and healing of peri-implant tissues.

β-TCP-based composite graft: Combinatorial strategy associating the synthetic biomaterial, autogenous bone (recovered during drilling) and CGF. This approach compensates for the low intrinsic bioactivity of β-TCP through the patient's cellular properties and biological signals.

Horizontal bone width: Dimensional measurement of the alveolar ridge performed by CBCT at 0, 2, and 4 mm apical to the implant platform. This is the primary indicator used in the study to quantify bone gain and its stability over an 18-month period.

"Pink and White" aesthetic results: Global clinical evaluation performed at 18 months, covering both soft tissue integration (pink aesthetics) and the quality of the prosthetic restoration (white aesthetics) in the critical anterior zone.

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