Context and objectives: iliac bone grafting in the face of post-traumatic challenges

Implant rehabilitation following dento-alveolar trauma frequently faces irregular bone loss and marked ridge atrophy. These complex volumetric defects compromise not only the primary implant stability, but also the viability of the final prosthetic project. To address these deficits, this single-arm prospective interventional study evaluated the efficacy of anterior iliac crest autograft reconstruction in 20 patients presenting with post-traumatic alveolar defects.

The precise objective of this study was to measure implant stability (primary endpoint) achieved six months after grafting, during implant placement. The authors also documented secondary criteria crucial for clinical practice: the graft success rate (horizontal and vertical gain), marginal bone loss, and the overall satisfaction of the included patients (aged 18 to 65 years).

The study is based on the hypothesis that the use of iliac bone, through its volume reconstruction capacity, allows for the restoration of an alveolar architecture compatible with high primary stability and an optimal implant survival rate, even in initially severely degraded sites. For the implantologist, the challenge is to confirm whether this massive reconstruction approach offers the predictability required to treat the sequelae of severe maxillary and mandibular trauma.

Study methodology: Iliac graft reconstruction

This single-arm prospective interventional clinical study was conducted on a cohort of 20 patients (men and women), aged 18 to 65 years. All subjects presented complex maxillary or mandibular post-traumatic alveolar bone defects, preventing immediate implant rehabilitation.

The experimental protocol was structured around the following steps:

• Bone reconstruction: Harvesting of autogenous grafts from the anterior iliac crest and placement on edentulous sites.
• Healing phase: A 6-month period was observed before the implant stage.
• Implantology and prosthetics: Placement of 30 dental implants followed by a complete prosthetic rehabilitation.

The analysis methods focused on several clinical and radiographic evaluation criteria:

• Implant stability: Primary evaluation measured in Ncm during placement (baseline) and at 6 months.
• Graft dimensions: Measurement of horizontal width and vertical height (in mm) preoperatively versus 6 months after the graft.
• Post-operative follow-up: Measurement of marginal bone loss (MBL) at 6 months, evaluation of graft success and patient satisfaction (85% reported satisfaction).
• Safety: Systematic recording of all adverse events, including complications at the donor site.

Results: Stability, Volumetry and Implant Survival

The analysis of data collected from 20 patients (30 implants) highlights a significant improvement in implant stability between placement and the 6-month follow-up. The insertion torque increased from an average of 59.7 ± 10.01 Ncm to 68.7 ± 10.17 Ncm (P < 0.001), confirming excellent osseointegration within the grafted autologous bone.

Dimensional Reconstruction of Defects

Iliac crest grafting has enabled a major correction of bone volumes. Dimensional gains, both horizontally and vertically, are statistically significant (P < 0.001):

Implant Survival and Clinical Evaluation

• Survival rate: 96.7% (29 out of 30 implants successfully maintained).
• Graft success: 100% (no graft loss reported).
• Marginal bone loss (MBL): A median value of 1.5 mm was recorded at 6 months (P < 0.001).
• Patient satisfaction: 85% of subjects reported being satisfied or very satisfied with the aesthetic and functional result.
• Complications: A single case of wound dehiscence at the donor site (iliac crest) was observed during follow-up.

Clinical analysis and significance of results

The results of this prospective study highlight the efficacy of iliac bone grafting for the reconstruction of complex post-traumatic alveolar defects. Clinically, the significant increase in horizontal width (from 2.1 ± 0.5 mm to 6.9 ± 0.8 mm) is the most critical point: it allows the transition from an unusable residual ridge to a volume permitting the placement of standard-diameter implants with robust primary stability. The improvement in implant stability, increasing from 59.7 Ncm to 68.7 Ncm after 6 months, confirms that the bone remodeling of the autogenous graft provides a secondary density favorable for prosthetic loading.

Comparison and study limitations

The implant survival rate of 96.7% observed here aligns with the standards of autogenous bone reconstructions, despite the irregular and often severe nature of traumatic bone loss. However, the study presents limitations: the 6-month follow-up remains short to evaluate the long-term stability of the marginal bone level, which already shows a median loss of 1.5 mm. Furthermore, the single-arm design (n=20) limits direct comparison with other guided bone regeneration (GBR) techniques or other donor sites.

Implications for practice

Donor site morbidity, often a deterrent to this technique, proved limited in this cohort with only a single case of skin dehiscence. High patient satisfaction (85%) suggests that the functional and aesthetic benefits of the rehabilitation significantly outweigh the invasiveness of the iliac graft. This approach therefore remains a gold standard solution for extensive maxillary and mandibular reconstructions where initial bone volume is virtually non-existent.

Summary of results

This prospective study of 20 patients demonstrates that the iliac graft significantly increases ridge width (from 2.1 ± 0.5 mm to 6.9 ± 0.8 mm) and height (from 7.2 ± 1.1 mm to 10.7 ± 1.3 mm). With an implant survival rate of 96.7% and an average primary stability reaching 68.7 Ncm after 6 months, this technique ensures a solid foundation for the rehabilitation of complex post-traumatic defects.

In concrete terms, for the practitioner:

• Critical bone volume: For severe transverse atrophies, the iliac bone is a predictable solution allowing a width gain of nearly 5 mm, essential for correct three-dimensional implant positioning.
• Healing time: Respect a 6-month delay between the graft and the placement of implants to benefit from optimal primary stability (increasing from 59.7 to 68.7 Ncm).
• Prosthetic anticipation: Incorporate a median marginal bone loss of 1.5 mm into your aesthetic planning and soft tissue management at 6 months post-loading.

Technical lexicon of the study

Post-traumatic dento-alveolar defects: Structural alterations following trauma, characterized by irregular bone loss and insufficient ridge volume, compromising implant positioning and prosthetic rehabilitation.

Iliac crest bone graft: Autologous bone tissue harvesting from the anterior iliac crest, used in this study to reconstruct horizontal and vertical volumes of deficient maxillary and mandibular sites.

Implant stability: Measurement of the mechanical and biological anchorage of the implant, expressed in Ncm (Newton-centimetre). It represents the primary endpoint of the study, increasing significantly from 59.7 ±10.01 Ncm to 68.7 ±10.17 Ncm in 6 months.

Marginal bone loss: Remodelling or resorption of peri-implant bone at the neck level. In this study, the median value observed is 1.5 mm at 6 months post-rehabilitation.

Prospective single-arm intervention study: Clinical research design where a group of patients (n=20) is followed longitudinally after receiving a specific treatment (iliac graft then implants), without comparison with a concurrent control group.

Implant survival rate: Percentage of implants maintained in the mouth at the end of the follow-up period. The study reports a rate of 96.7%, corresponding to 29 functional implants out of the 30 initially placed.

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