Dental implants have revolutionized contemporary dentistry by providing durable, esthetic, and functional solutions for tooth replacement. Their ability to osseointegrate with bone tissue enables stability and longevity to support a variety of fixed and removable prostheses. To ensure optimal implant success, including esthetics, phonetics, function, and resistance to peri-implant disease, focus has shifted beyond osseointegration to the preservation and regeneration of surrounding hard and soft tissues. Oral regenerative procedures may be performed prior to surgical implant placement, simultaneous with implant surgery, and/or after implant placement or restoration. A paradigm shift from osseointegration to a more holistic assessment of implant success has placed an emphasis on biologically driven treatment approaches, accentuating optimal tissue regeneration, esthetic outcomes, and long-term peri-implant health.
Regenerative biomaterials can be utilized to address clinical challenges such as alveolar ridge deficiencies, peri-implantitis, and soft-tissue defects. Such biomaterials include autogenous grafts, allografts, xenografts, scaffolds, and barrier membranes. Further, the use of these regenerative materials may be augmented with growth factors and/or biologics to enhance outcomes. These materials can enable clinicians to restore the biological foundation essential for implant success. Moreover, integration of digital technologies into diagnosis, planning, and execution may enhance the predictability and precision of regenerative implant therapies.
Barrier membranes and bone grafts or substitutes remain the cornerstone of regenerative strategies in implant dentistry. The primary categories of biomaterials used in periodontal and peri-implant regeneration include barrier membranes, grafting materials, biologic agents, and, more recently, 3-dimensional scaffolds. Technological advances such as cross-linked collagen membranes, titanium-reinforced barriers, and 3D-printed scaffolds have refined guided bone regeneration (GBR) by improving defect conformation, stability, and outcomes. (Table 1, which can be viewed by visiting compendiumlive.com/go/cced2099, summarizes the main advantages and disadvantages associated with the different types of membranes and bone grafts available for GBR.)
Guided Bone Regeneration and Barrier Membranes
GBR relies on cell-occlusive membranes to create a secluded space for multipotent stem cells to populate defects while excluding soft-tissue interference.1 Membrane porosity plays a crucial role in nutrient diffusion and cell migration. Preclinical studies suggest that moderate porosity (25 µm to 100 µm) promotes early bone formation, while completely occlusive designs may hinder it.2 In systemic conditions like diabetes, perforated membranes allow mesenchymal cell influx from adjacent tissues, improving outcomes.3 Nonresorbable membranes like expanded polytetrafluoroethylene (e-PTFE) and high-density PTFE (d-PTFE) offer mechanical stability and biocompatibility but present challenges compared to resorbable membranes, such as bacterial contamination if exposed to the oral environment, poorer soft-tissue integration, and the need for surgical removal.4,5 To address potential membrane collapse in large defects, titanium-reinforced variants (Ti-d-PTFE) have been developed. These demonstrate poorer outcomes than resorbable membranes after exposure and/or infection, which may prompt clinicians to utilize resorbable alternatives.5
Recent research emphasizes the bioactivity of membranes beyond their barrier function. Membranes can be impregnated with host cells that secrete pro-osteogenic factors or modulate immune responses, which may augment healing.5 Emerging strategies include embedding growth factors and/or antimicrobial agents within membrane structures to address complex clinical conditions.6 The use of double-layer membranes has also shown potential benefits in enhancing graft stability and barrier longevity, although outcomes vary depending on the clinical scenario and membrane type.5,7 Ultimately, no membrane to date offers an ideal combination of physical, biological, and clinical handling properties for all clinical scenarios. Future development should focus on functionally graded membranes, which present variable porosity, mechanical strength, and bioactivity across their structure. These innovations hold promise for improving GBR predictability, especially in medically compromised or challenging anatomical environments.5
Driven by the drawbacks of nonresorbable barriers, resorbable membranes have gained favor because they eliminate second-stage surgery and offer improved clinical handling. These membranes are made from natural collagen or synthetic polymers such as polylactic or polyglycolic acid. Bilayer designs enhance tissue integration and prevent epithelial infiltration. Advanced versions incorporate 3D printing and asymmetric porosity to promote selective cell behavior. Achieving proper stabilization via tacks, tenting screws, or sutures is critical, however, because micromovement of barrier membranes can compromise healing.5 Although cross-linking can prolong membrane life, it may impair integration or provoke inflammation. Overall, both resorbable and nonresorbable membranes have shown similar long-term GBR outcomes.2
Role of Bone Grafts and Substitutes
Bone grafts play essential roles in space maintenance, clot stabilization, and bone healing. They are classified by origin: autologous, allogeneic, xenogeneic, or alloplastic (synthetic). Ideal grafts are biocompatible, porous, osteoinductive/conductive, angiogenic, biodegradable, and mechanically supportive.2 While autografts may contain osteoblasts and/or osteoblastic progenitor cells (ie, they are osteogenic), they are limited by donor site morbidity. Allografts like freeze-dried bone allograft (FDBA) and demineralized FDBA (DFDBA) allow an osteoconductive scaffolding and, in the case of DFDBA, possible osteoinductive activity due to retained growth factors.8 Even so, the osteoinductive potential of DFDBA can vary significantly depending on donor age, processing techniques, and storage conditions. However, differences in clinical outcomes between FDBA and DFDBA allografts are minimal.
Autogenous bone, harvested from the same individual, has long been considered the gold standard for bone grafting due to its osteogenic, osteoinductive, and osteoconductive properties and lack of immunogenic risk. Common intraoral donor sites include the alveolar bone, tuberosity, ramus, retromolar area, and symphysis. While effective in treating intrabony defects and edentulous areas, autogenous bone’s clinical use has declined due to donor site morbidity, longer surgical time, potential contamination, and unpredictable resorption rates. Extraoral harvesting is typically reserved for larger reconstructive case types due to risk-benefit analysis related to the quantity of bone required for defects and enhanced healing provided by extraoral bone graft materials.8
Allogeneic bone grafts are derived from human donors of the same species but different genetic backgrounds. Such bone allografts are available in forms like fresh-frozen (FFBA), FDBA, and DFDBA, and they eliminate the need for a second surgical site, reducing morbidity and allowing for larger graft volumes. FFBA, although highly osteoinductive and osteoconductive, is rarely used today due to disease transmission risks. FDBA is primarily osteoconductive and often combined with autografts to enhance regenerative outcomes. DFDBA may express bone morphogenetic proteins, offering osteoinductive potential. Both FDBA and DFDBA are processed to reduce antigenicity, but DFDBA has demonstrated faster resorption compared to FDBA. Both demonstrated slower replacement by host bone compared to autografts.8
Deproteinized bovine bone matrix (DBBM) is the most common xenograft used in peri-implant and periodontal regeneration. While DBBM provides excellent volumetric stability and osteoconductivity and mimics human bone in structure and porosity, it does not actively induce bone formation. Studies show it supports early bone formation but may slow long-term remodeling.7 Multiple studies consistently demonstrate that autogenous bone chips lead to the highest rates of early new bone formation, while DBBM exhibits the slowest resorption and substitution over time compared to other graft materials.7 Combining DBBM with bone-conditioned media, fluids rich in growth factors derived from autogenous bone have shown promise in enhancing regenerative capacity, although clinical protocols remain unstandardized.5,8
Synthetic bone substitutes, such as hydroxyapatite, β-tricalcium phosphate, and biphasic calcium phosphate, are often used in combination with growth factors. Such grafts may provide customizable properties and are available in various forms (moldable, injectable, 3D-printed). Researchers are also exploring grafts that combine bioactive glass or polymers for improved mechanical performance while maintaining osteoconductivity.5 Further, the volumetric and physical stability of synthetic grafts may be combined with other graft types to allow for the optimal properties associated with all graft types.
Bone grafts are particularly critical in cases where membrane collapse is likely due to defect morphology or mechanical limitations. However, maintaining dimensional stability is a delicate balance, as excessive compression, graft migration, or rapid resorption can impair outcomes. Conversely, slow-resorbing grafts help preserve space but may delay the remodeling needed for timely bone regeneration.5 A tailored approach that balances scaffold longevity with remodeling dynamics is key to optimal results.
About the Authors
Priscilla Sosa, DMD
Periodontal Resident, University of Alabama at Birmingham School of Dentistry, Birmingham, Alabama
Layal Bou Semaan, DMD, MS
Periodontal Resident, University of Alabama at Birmingham School of Dentistry, Birmingham, Alabama
Maria L. Geisinger, DDS, MS
Professor, Acting Chair, Director, Advanced Education Program in Periodontology, Department of Periodontology, University of Alabama at Birmingham School of Dentistry, Birmingham, Alabama; Diplomate, American Board of Periodontology
