Objectives The primary objective was to evaluate clinically the efficacy of modified perforated collagen membrane (PCM) and/or (L-PRF) in combination with xenogeneic block bone graft in the vertical alveolar ridge augmentation. Secondary outcome measurements were to evaluate histologically the quality of newly formed tissues. Materials and Methods Six adult mongrel dogs were enrolled in this randomized blinded study. After defect preparation, xenogeneic screw fixed block graft was covered by occlusive collagen membrane in the group (1) (Block + CM - control group ), while group (2), (L-PRF) membrane was added first before top coverage by occlusive collagen membrane (Block + L-PRF + CM). Groups (3) and (4) were identical to the first two groups except that, the occlusive collagen membrane was replaced by a perforated one, so group (3) was (Block + PCM ) and group (4) was (Block + L-PRF + PCM). Following a healing period of 2 months, dogs were submitted to surgical reentry phase for clinical and histological evaluation. Results Clinically, no significant differences were found among all groups regarding vertical and horizontal ridge dimensions (P = 0.155, 0.492 respectively). Histomorphometric analysis revealed that the percentage of total bone area and mature bone was significantly higher in group 4 (69.36 ± 2.72), (33.11 ± 5.18) compared to control group (59.17 ± 4.27),( 21.94 ± 2.86) (P = 0. 027, P = 0.029). Conclusion The use of xenogenic block grafts in combination with a double-layered perforated collagen-L-PRF membrane in vertical ridge augmentation appeared to improve the inductive power of this challenging defect type. Clinical Relevance: Size and number of perforations may affect the mechanical and handling properties of the membrane.

Objectives This study evaluated clinically and histologically the efficacy of modified perforated collagen membrane (PCM) and/or leukocyte- and platelet-rich fibrin (L-PRF) in combination with xenogeneic block bone graft in the vertical alveolar ridge augmentation. Materials and methods Six adult mongrel dogs were enrolled in this randomized blinded study. After defect preparation, xenogeneic screw-fixed block graft was covered by an occlusive collagen membrane in group 1 that represented the control group (Block + CM). In group 2, L-PRF membrane was added first before top coverage by occlusive collagen membrane (Block + L-PRF + CM). Groups 3 (Block + PCM) and 4 (Block + L-PRF + PCM) were identical to the first two groups except that the occlusive collagen membrane was replaced by a perforated one. Following a healing period of 2 months, the dogs were submitted to the surgical reentry phase for clinical and histological evaluation. Results Clinically, no significant differences were found among all groups regarding vertical and horizontal ridge dimensions (p = 0.155, 0.492, respectively). Histomorphometric analysis revealed that the percentage of the total bone area and mature bone was significantly higher in group 4 (69.36 ± 2.72, 33.11 ± 5.18) compared to the control group (59.17 ± 4.27, 21.94 ± 2.86) (p = 0. 027, p = 0.029). Conclusion The use of xenogenic block grafts in combination with a double-layered perforated collagen L-PRF membrane in vertical ridge augmentation appeared to improve the inductive power of this challenging defect type. Clinical relevance Size and number of perforations may affect the mechanical and handling properties of the membrane.