CBCT-based comparative evaluation of three-dimensional bone volume and density following transcrestal sinus floor augmentation: a randomized clinical trial

Rehabilitation of the posterior maxilla with dental implants is challenging because of limited residual bone height and poor bone quality. Transcrestal sinus floor elevation is a minimally invasive technique that increases bone volume and density, facilitating implant placement. Although venous blood, injectable platelet-rich fibrin (i-PRF), and synthetic alloplastic grafts have been proposed to enhance bone regeneration, comparative evidence regarding three-dimensional endo-sinus bone volume and regional bone density remains limited. This study evaluated and compared these outcomes following transcrestal sinus floor augmentation using venous blood, i-PRF, an alloplastic graft, and without graft material. This prospective randomized controlled trial included 64 participants with posterior maxillary residual ridge height of 4–6 mm. Participants were allocated by computer-generated block randomization into four groups ( n = 16): without graft, venous blood, i-PRF, and alloplastic graft. All underwent transcrestal sinus floor elevation using the CAS kit with simultaneous implant placement and 0.5 cc of the allocated material. Three-dimensional endo-sinus bone volume and regional bone density were assessed by CBCT after 6 months using Planmeca Romexis ® software by a blinded assessor. Intergroup comparisons were performed using one-way ANOVA with Tukey post-hoc tests (α = 0.05). Significant differences were observed in three-dimensional bone volume ( P < .001), with the alloplastic graft group demonstrating the greatest endo-sinus bone volume. Bone density was significantly higher at the apical, buccal-apical, and palatal-apical regions ( P < .001), whereas no significant differences were observed in the mid-sinus regions. Venous blood and i-PRF showed modest increases compared with blood clot alone, with no significant differences between them. Alloplastic graft-assisted transcrestal sinus floor augmentation resulted in greater three-dimensional bone volume and higher apical bone density at 6 months compared with autologous grafting and no-graft approaches. Among the evaluated approaches, the alloplastic graft group demonstrated the highest measured bone volume and bone density values. i-PRF was associated with radiographic bone formation but did not demonstrate a comparable volumetric outcome. The no-graft and venous blood groups showed comparatively lower radiographic bone volume. These findings suggest that alloplastic grafting may provide favorable 6-months radiographic outcomes following transcrestal sinus floor augmentation; however, longer-term clinical and histological studies are needed to confirm these findings and clarify the underlying biological mechanisms. Clinical Trials Registry of India (CTRI/2025/03/083409) on 25/03/2025.