Bone regeneration and biomaterials 2024(1).pdf

BONE REGENERATION AND BIOMATERIALS IN IMPLANT DENTISTRY DENT4060 – Semester 1 Dr. Tulio Fernández-Medina DDS., MClinDent, PhD Hon. Senior Lecturer-School of Dentistry 2024 Learning Objetives Understand the conformational changes in alveolar b...

BONE REGENERATION AND BIOMATERIALS IN IMPLANT DENTISTRY DENT4060 – Semester 1 Dr. Tulio Fernández-Medina DDS., MClinDent, PhD Hon. Senior Lecturer-School of Dentistry 2024 Learning Objetives Understand the conformational changes in alveolar bone after tooth extraction Be able to identify the different implant supported prostheses and their corresponded augmentation needs Be able to identify the main biological process in bone formation: ostegenesis, osteoinduction and osteoconduction Identify membranes, bone graft substitutes and bioactive molecules used in bone augmentation Understand the biology of bone formation around dental implants Be able to identify Implant Stability Quotient (ISQ) for measuring implant stability and biological boundaries. Conformational changes in alveolar bone after tooth extraction Bone defects in dentistry Alveolar bone reconstruction paradigm Araujo et Al. J Clin Periodontol 2005 Conformational changes in alveolar bone after tooth extraction Bone defects post-extraction Collapse of cortical bone wall especially buccal side composed mainly for bundle bone Sensible diminishing in blood perfusion from PDL. Affects survival of cortical bone Wound healing contraction Bundle bone (Histologic name for alveolar bone that provides attachment to PDL fibres) disappear after 2 weeks and is gradually replaced by woven bone (Phase I) Phase 2 included resorption that occurred from the outer surfaces of both bone walls. Araujo et Al. J Clin Periodontol 2005 Conformational changes in alveolar bone after tooth extraction Jinmeng Li et al.Mechanical aspects of dental implants and osseointegration: A narrative review,Journal of the Mechanical Behavior of Biomedical Materials,2020. Conformational changes in alveolar bone after tooth extraction Seibert JS. Reconstruction of deformed, partially edentulous ridges, using full thickness onlay grafts. Part I. Technique and wound healing. Compend Contin Educ Dent. 1983. Comprehensive implant treatment approach Implant supported prostheses Unitary Implant Implant Supported Bridge Implant Supported Hybrid Prosthesis Overdentures BIOMECHANICAL DRIVEN DISTRIBUTION OF IMPLANTS Biological Process in bone formation Osteoinduction: This term means that primitive, undifferentiated and pluripotent cells are somehow stimulated to develop into the bone-forming cell lineage. One proposed definition is the process by which osteogenesis is induced. Osteoconduction: This term means that bone grows on a surface. An osteoconductive surface is one that permits bone growth on its surface or down into pores, channels or pipes. Biomaterials Osteoconduction: guides the reparative growth of the native bone. Biomaterials used for the bone graft serves as the framework for the new bone growth that is propagated by the patient’s natural bone. Osteoblasts from the defected area that is being grafted utilize the grafting material as a scaffold. The osteoblasts use this framework to spread and create new bone. Guiding new bone growth requires the use of bone-graft material that is osteoconductive. Osseointegration: direct contact (at the light microscope level) between living bone and implant (Branemark-1981). Osseointegration is also histologically defined as the direct anchorage of an implant by the formation of bony tissue around the implant without the growth of fibrous tissue at the bone–implant interface (Albrekson-1993). Another more biomechanically oriented definition of osseointegration has been suggested: “A process whereby clinically asymptomatic rigid fixation of alloplastic materials is achieved, and maintained, in bone during functional loading” (Zarb-1991). Biological Process in bone formation OSTEOGENESIS (Development of bones) There are two major modes of bone formation, or osteogenesis, and both involve the transformation of a preexisting mesenchymal tissue into bone tissue. The direct conversion of mesenchymal tissue into bone is called intramembranous ossification. This process occurs primarily in the bones of the skull. In other cases, the mesenchymal cells differentiate into cartilage, and this cartilage is later replaced by bone. The process by which a cartilage intermediate is formed and replaced by bone cells is called endochondral ossification. Osseointegration/ Fibro-osseointegration Under ideal conditions, the titanium implant is not 100% covered by viable bone. Some percentage (depends on many factors) will lead into fibrous tissue formation at the interphase. The more bone/implant contact area, the better mechanical properties. Differential fiber orientation interphase at the soft tissue (abutment) compared to natural dentition.  Titanium alloy:commercially pure titanium (cpTi) and Ti-6Al-4V Machined Surface SLA Surface HA-coated surface Osseotite TiUnite OsseoSpeed Biological Process in bone formation Biological Process in bone formation Biological Process in bone formation Biological Process in bone formation Biological Process in bone formation  Implant Stability Quotient (ISQ) The resonance frequency analysis technique can supply clinically relevant information about the state of the implant–bone interface at any stage of the treatment or at follow-up examinations. The resonance frequency analysis technique evaluates implant stability as a function of the stiffness of the implant–bone interface and is influenced by factors such as bone density, jaw healing time and exposed implant height above the alveolar crest High stability: ISQ >70 My implant is stable, I can proceed with my rehabilitation Current strategies to achieve bone augmentation Guided bone regeneration Principle Exclusion of soft tissue cells Space maintenance Clot stabilization Bone particles for regeneration (50/50) Advantages Graft availability 5 -10 CC ≤ 2 CC EXTRA-ORAL INTRA-ORAL Horizontal bone defects Disadvantages Decreased osteoinduction Low predictability in vertical defects Titanium reinforced membranes: lack of tissue integration ≤ 70 CC 30-50 CC ≤ 25 CC Elgali et Al. Eur. J Oral Sci. 2017 Yxoss CBR Guided Bone Regeneration Elgali et Al. Eur. J Oral Sci. 2017 Membranes, bone graft substitutes and bioactive molecules Membranes, bone graft substitutes and bioactive molecules Mauren Maria Thanks!!