Efficacy of sinus crestal elevation with demineralized dentin matrix at the apex of the implants

BACKGROUND: This study evaluated the clinical and radiographic outcomes of using demineralized dentin matrix (DDM) as a graft material at the implant apex during crestal sinus floor elevation. We hypothesized that DDM would promote predictable bone regeneration at the sinus floor and facilitate implant stability with minimal surgical morbidity. METHODS: A retrospective analysis was performed on 55 implants placed with transcrestal sinus floor elevation and DDM grafting at the implant apex in the posterior maxilla. Radiographic outcomes were assessed with CBCT. The primary variable was vertical bone gain at the former sinus floor. Secondary outcomes included the proportion of implant protrusion length replaced by new bone (bone gain), implant survival, and sinus health. Pearson correlation and t-tests were used to analyze relationships between implant protrusion length, sinus width, and bone gain. RESULTS: All 55 implants remained functional and osseointegrated after a mean follow-up of 48.1 ± 32.7 months, yielding a 100% survival rate. The mean implant protrusion into the sinus was 3.42 ± 1.27 mm, and mean bone gain at the sinus floor was 1.97 ± 1.18 mm. On average, 61.5% of the protruded implant length was covered by new bone. Implants protruding ≥ 4 mm showed significantly greater absolute bone gain than those < 4 mm (2.50 vs. 1.65 mm, p = 0.04), although the bone fill percentage was similar between groups. Implants in narrower sinuses exhibited higher bone fill (77.8% vs. 46.8%, p < 0.01) and greater bone gain than those in wider sinuses. No significant sinus complications or graft failures occurred. CONCLUSION: Within the limitations of this retrospective study, crestal sinus elevation with DDM grafting at the implant apex proved to be a safe and effective minimally invasive technique, consistently yielding bone regeneration and excellent implant survival in the posterior maxilla.