Biomaterials Used in Oral and Maxillofacial Surgery PDF

BIOMATERIALS USED in ORAL AND MAXILLOFACIAL SURGERY Dr. Dt. Erim TANDOĞDU [email protected] Biomaterial Classification of Bone Defects Bone defects are classified according to their characteristics as follows: Localised bone...

BIOMATERIALS USED in ORAL AND MAXILLOFACIAL SURGERY Dr. Dt. Erim TANDOĞDU [email protected] Biomaterial Classification of Bone Defects Bone defects are classified according to their characteristics as follows: Localised bone defects. Dehiscence defects: vertical defects on the vestibular surface of the implant along the alveolar crest Fenestration defects are window-shaped defects on the vestibular surface of the implant. Residual bone defects Gravitational cavity defects 5-walled defects: Cyst cavities and extraction cavities are these types of defects. It is expected to heal with new bone formation as a result of appositional growth. 4-walled defects: An additional bone wall is lost at the recipient bone site. In such cases, the use of alloplastic material or freeze-dried bone is recommended. 2 or 3-walled defects: Defects with loss of 2 or 3 bone walls. Requires the addition of autogenous bone graft. 1-walled defects: Defects with loss of all 5 walls. They are compensated with autogenous bone graft.  Repair of bone defects of congenital, traumatic, degenerative, inflammatory, infectious, cystic and neoplastic etiologies Segmentation of atrophic maxilla and mandible Preprosthetic surgery procedures for soft tissue T.M.E. surgery Orthognathic surgery operations Sinus lifting and implantation Surgical treatment of jaw fractures Surgical treatment of oro-antral and oro-nasal fistulas  Bone formation occurs either by intramembranous ossification, which is the direct mineralisation of the matrix secreted by osteoblasts, or by endochondral ossification, which is the deposition of bone matrix on the pre-existing cartilage matrix. Hard Tissue Graft Materials Used in Oral and Maxillofacial Surgery Hard Tissue Graft Graft materials contribute to Materials Used in bone healing by 3 different Oral and Maxillofacial mechanisms. Surgery 1. Osteogenesis Bone graft materials have the ability to form bone directly from osteoblast cells with the organic materials they contain. Such organic substances are capable of osteogenesis even in the absence of undifferentiated mesenchyme cells in the tissue. The only graft material with osteogenesis character is autogenous bone.  It is a term used to express the provision of bone 2. Osteoinduction formation by increasing osteoblastic activity.  Some graft materials form a scaffold (roof) for new bone tissue to form 3. Osteoconduction from the edges of the existing defect on the surface. Bone graft materials are basically classified as follows. Allografts Allografts are bone tissues obtained from individuals of the same species as the recipient but from genetically different individuals. Living people or cadavers Allografts Frozen bone allografts Freeze-dried bone allografts Demineralised freeze-dried bone allografts (DDKKA) a) Frozen bone allografts Osteoinductive b) Freeze-dried Osteoconductive By subjecting the bone to freezing at -80 C  c) Demineralised freeze-dried bone allografts (DDKKA) It is passed through a hydrochloric acid bath, ethanol and chloroform are applied and the fats are dissolved. With these processes, 90 % of the proteins are destroyed. One of the proteins remaining in bone is bone-forming protein (BMP), which acts as a stimulator of bone formation.  c) Demineralised freeze-dried bone allografts (DDKKA) They show osteoinductive properties. BMPs are more commonly observed in cortical bone. bone morphoganetic protein Allografts They carry risks of infection and inflammation. It can be found in any quantity. Heterogeneous Grafts (Xenografts) a) Hydroxyapatites of animal origin It is obtained by complete deproteinisation of mammalian animal (cattle, horse, pig) bones Deproteinised bovine bone grafts are highly biocompatible and osteoconductive for proliferating bone cells due to their low resorption rate Block forms of heterogeneous grafts are used as onlay grafts in maxillofacial surgery Granule forms are used in periodontal bone defects, extraction cavities and small cyst operations.  b) Calcium carbonates of coral origin Coral-derived grafts are osteoconductive, easy to prepare, easy to shape, biocompatible and low cost grafts. It is an ideal graft material due to its structural proximity to bone and biologically inert material. Synthetic Graft Materials (Alloplasts)  a) Bioceramics They are obtained by fusing (sinterisation) hydroxyapatite powders with each other under high heat and pressure. b) Bioactive glasses It is suggested that these materials with bioactive properties cause rapid new bone formation by directing and enhancing osteogenesis. c) Polymers When in close contact with the alveolar bone, it acts as a scaffold for new bone formation and shows osteoconductive effect.  The recipient and donor are the same person. In the reconstruction of bone defects, autogenous AUTOGREFTS bone grafts with osteoinductive and osteoconductive potential and osteogenic cells are primarily preferred. Since they have live cell capacity, they stimulate osteoblasts at the recipient site.  Today, autogenous cancellous (spongious) bone graft is considered as the "gold standard".  They have the advantage that they revascularise rapidly and do not cause immunological reactions;  The need for a second surgical procedure, Often requires general anaesthesia Prolonging the duration of the surgical procedure, Increasing blood loss Early resorption of autograft, Pain in the donor area, Paresthesia Limitation of movement, Morbidity at the donor site and There are some disadvantages such as not obtaining the desired amount  Grafts from membranous bones show less resorption than endochondral grafts. The reason for this is; Early revascularisation, Biochemical similarity in protocollagens Potential for better bonding in the maxillofacial region It has a higher inductive capacity due to the high amount of bone morphogenetic proteins and growth factors. When it is desired to have less resorption during the healing period in onlay graft procedures the use of donor sites ossified via the intramembranous route is recommended  Mandibular symphysis region Mandibular ramus region Mandibular lower edge Coronoid process Zigoma Retromolar region Tuber region Outside the mouth Iliac crest Kosta Calvary Proximal tibia They can be obtained from vascularised fibula.  The bone growth mechanism in autogenous bone grafts consists of 3 stages. Phase 1 Phase 2 Phase 3 Intraoral bone grafting sites Use of block calvarium graft for augmentation of severely atrophic mandible Simfiz Region  After clinical and radiographic evaluations, vestibular or sulcular incision is preferred for access to the symphysis. The vestibular incision is planned 10 mm below the mucogingival line. Osteotomies should be performed 5 mm below the apices of the teeth. Osteotomies should be 5 mm away from the mental foramen.  Easier graft harvesting than symphysis, Less postoperative discomfort, Less neurosensory complaints, Less incision line openings, Providing deeper local anaesthesia, It has the advantage that facial morphological changes cause less concern. Alveolar crest augmentation Reconstruction of orbital complex fractures Iliac Crest The iliac crest is the most preferred extraoral donor site for alveolar bone augmentation. It contains more carancellous bone than other extraoral donor sites and has the highest corticocancellous ratio. Proximal Tibia Advantages Costas Costochondral grafts have been an ideal graft in temporomandibular joint reconstruction due to their anatomical and biological characteristics similar to the mandibular condyle, providing adequate function and continuing development in the absence of the disc.  5th, 6th or 7th rib to obtain the graft as a transmitter. However, due to the position of the heart, the right side is preferable. CALVARIA The Parietal region is the most suitable. It is not taken from the temporal region. There is no diploe layer and the bone is thin.  Stratified Suturing Periosteal suturing Subcutaneous suture Scalp suturing 24 hour printed bandage In some cases, a drain is placed.  Compared with the iliac graft, the calvarial graft has been reported to have superior retention and greater radiographic density. Less resorption Thick cortical bone around the fibula It ensures that the bone is resistant to occlusal forces.  ✔ Palatinal mucosa Autogenic soft tissue ✔ Mucosa grafts from cheek and tongue donor sites used for ✔ Skin grafts grafting ✔ Fascia grafts ✔ Myocutaneous grafts  Injecting concentrated platelet solutions, known as PRP, into the surgical site has been shown to create a stimulus that initiates the healing process. Human platelets are rich in important protein products and connective tissue growth factors. Injecting these growth factors into injured and damaged bones, ligaments, tendons, muscles and other soft tissues stimulates the body's natural repair processes. Guided Bone Regeneration It has also been shown to increase mature trabecular bone density by 15-30%.  Repair of bone defects caused by congenital, traumatic, degenerative, inflammatory, infectious, cystic and neoplastic etiologies Segmentation of atrophic maxilla and mandible Orthognathic surgery operations Sinus lifting and implantation Surgical treatment of oroantral and oronasal fistulas  MEMBRANE TYPES NON-RESORBABLE MEMBRANES e-PTFE (Expanded polytetrafluoroethylene) Other membranes RESORBABLE MEMBRANES 1-Synthetic Polymers Polyurethane Polylactic acid Lactide/glycolide copolymers (e.g. polyglactin-910) 2- Polylactic acid mixed with citric acid Natural, biodegradable (e.g. collagen membrane) 3-Calcium sulphate Properties Required in Barrier Membranes  First commercial barrier membrane NON-RESORBABLE material e-PTFE. It is a cellular barrier, MEMBRANES biocompatible and provides volume for tissue proliferation. Wait 4-6 weeks after the membrane is placed. At the end of this period, the membrane is removed by a second surgical procedure  Topical application of chlorhexidine to the area NON RESORBABLE MEMBRANES RESORBABLE MEMBRANES 1- Polyglycoside synthetic polymers (polylactic acid, polylactate/polygalactide copolymers) 2-Collagen 3-Calcium Sulphate (CS)