Aim: ‎To assess the vertical height gain in atrophic posterior mandible using different forms of ‎xenograft through an interpositional bone grafting procedure (sandwich technique). Materials and methods: Patient ‎were separated into two groups, Group A (Study Group):  received augmentation through ‎the use of an organic bovine bone particulate. Group B (Control Group):  received ‎augmentation through the application of an organic bovine bone block. This ‎study was conducted on 16 patients suffering from posterior mandibular partial edentulism ‎with an inadequate bone height enough for favorable implant placement. The alveolar ‎vertical dimension measured ranges from or equal to 5-8 mm from roof of the inferior ‎alveolar canal to the alveolar crest. Both groups had equal percentages of both genders. ‎ Results:  The mean age of the participants in the block group was (35.36±2.62) years, in the ‎particulate group it was (36.07±7.23), and the variation was not significant (p=0.798). ‎Measured bone height in the block group was greater than the particulate group with the ‎distinction being significant after the end of the follow-up interval (p<0.001). Bone height ‎gain measured in the block group (3.83±0.31) (mm) was significantly greater than that ‎measured in the particulate group (3.56±0.14) (p=0.047). Conclusion: Bone height gain ‎measured in block group was significantly higher than that measured in particulate group.