Osseointegration in Oral Implantology: Biological Phases, grafts Success Criteria, and Prevention of Complications, A Comprehensive Review

Background: Osseointegration is the intimate biological connection between bone and a load-bearing implant which is the cornerstone of modern implant dentistry. When bone volume or quality is inadequate, graft materials are required to reconstruct the alveolar ridge and provide a stable host bed. Over the past three decades, xenografts, alloplastic substitutes, bovine-derived matrices, and coral-based scaffolds have been explored as alternatives to autogenous bone. In light of these developments, the present review synthesizes experimental and clinical evidence to elucidate the biological phases of osseointegration, establish measurable success criteria, and compare the biological behavior, strengths, and limitations of the four major graft categories, while further highlighting preventive strategies to reduce biological and mechanical complications.Methods: PubMed, Scopus, and Web of Science, 1980-April 2025, were searched to conduct the systematic narrative review. Keywords were osseointegration, dental implant, xenograft, bovine graft, alloplastic graft and coral graft. The inclusion criteria were restricted to peer-reviewed studies with English language reporting histological, radiographic or biomechanical outcomes.Results: Long-term dimensional stability was provided by xenograft and bovine materials, remodeling was slowed; alloplastic grafts were found to turnover more quickly and have higher early bone formation; coral-derived scaffolds were found to provide natural porosity but have limited mechanical strength. When properly handled all materials were biocompatible.Conclusion: The graft classes have a unique role to play in bone regeneration. Effective osseointegration requires balancing between material properties and defect morphology, precision of surgery and host healing. There is still necessity of standardized long-term studies with the aim of perfecting the material choice.