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![II] Conge et al. (1978) CLASSIFIED AS
Osseous Non-
Osseous
Autograft
s
Allografts
Pedicle
Bone
swaging
Free grafts
Intraoral
Bone
coagulum
Bone blend
Tuberosity
Extraction sites
Edentulous
ridge
Extraoral
Iliac crest
Tibia
Organic
Collagen
Dentin
Cementum
Coral
Sclera
Cartilage
Inorganic
(Alloplasts)
POP
Polymers
Ca
carbonates
Ceramics
Human bone FDBA
DFDBA
Resorbable
TCP, HA
Non-Resorbable
HA, Bioglass
Xenograft
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Bone grafts
- 2. BONEGRAFT MATERIALS ANDPROCEDURES AND FIRSTSTAGESURGERY Dr Mansi
- 3. Contents • Introduction • History •Definitions • Types of grafts • Successful keys for grafting • Choosing a graft material • Guided tissue regeneration • Membranes
- 4. • Maxillary sinusbone grafting • Grafting to improve ridge dimension • Ridge preservation • Immediate implant placement • First stage surgery • Socket Preservation • Conclusion • References
- 5. Introduction • Bone graftingis a dynamic phenomenon. • A successful bone graft… • In their early application, bone grafts were considered a mere strap lattice. • Today, bone grafts are viewed as biologic structures.
- 6. TYPESOF BONE GRAFTS2 •GRAFT (according to GPT) : Tissue or material used to repair a defect or deficiency Autograft / Homograft Allograft Isograft Composite grafts Xenograft / Heterograft Alloplast
- 7. HISTORY OF AUTOGENOUSBONE grafts fgraGRAFTING1 Axhausen in 1907 demonstrated in an experiment that periosteally covered bone grafts exhibited osteogenesis. . Ollier 1867 reported transfer of periosteum and bone Barth in 1893 he revealed that several days after bone graft transfer, the graft is dead. Von Walter 1882 described use of corticocancellous bone graft. 1682 VanMeekren transplanted canine skull bone to calvarial defect.
- 8. Okland and associatesin 1985 put forward that survival of surface cells in autogenous bone grafts is much more superior Mowlem in 1944 and later in 1963, used cancellous bone grafts and demonstrated its superiority over cortical bone grafts. Gallie & Robertson 1918, concluded that rate of survival of cells was better with cancellous bone than with cortical. Phemister in 1914 concluded that some osteogenic cells survive by diffusion of oxygen and nutrients from the recipient bed.
- 9. ALLOGENICBONEGRAFTING History: Bone induction principlewas described by Urist for allogenic bone in 1953 Urist and Burwell in 1968 and later in 1969 gave the use of allogenic bone either fresh or frozen and dried. Urist in 1968 also described that allogenic bone is replaced by new host bone.
- 10. Indicationsfor BoneGrafting 2 ØJaw resection following malignancy / other pathology Ø Extensive trauma Ø In orthognathic surgery Ø As an onlay material in facial aesthetic surgery Ø Large bony defects created by cysts and tumors Ø In preprosthetic surgery as an onlay, fill material Ø In cleft patients. Ø In implantology e.g. : sinus lift procedure Ø In periodontal surgery
- 11. Objectives Of BoneGrafting (Schallhorn, 1977) • Pocket reduction/Elimination • Gain in clinical attachment • Restoration of host alveolar bone • Regeneration of new bone, cementum & periodontal ligament • To establish a healthy maintainable environment
- 12. Characteristics of IdealBone Graft Materials, Boyne in 1973 – Should be readily available and not require surgical intervention at a second donor site. – Should provide rapid osteogenesis. – Should not elicit immunological responses. – Should enhance revascularization. – Should be highly osteoinductive. – Should provide for osteoconduction. – Should provide for the formation of new attachment in periodontal lesions. – Should not impede bone growth.
- 13. Advantages Of BoneGrafts • Regeneration of the attachment apparatus is possible. • It is possible to reverse the disease process. • Increased tooth support, improved function, and enhanced esthetics. • All categories of intra osseous defect and certain furcation defects. • Idealistic therapeutic objectives may be achievable • Disadvantages of bone grafts (Mellonig 1992) • Increases treatment time. • Autografts require two sites. • Increased postoperative care. • Bone grafts take a long time to heal. • Need for multiple therapy-secondary surgeries. • Availability & the added expense of graft material. • Technique sensitive.
- 14. Physiologicconsiderations and process,graft materials can be divided as3: • Osteoinduction: is the induction of bone formation in the absence of a bony host site. • Eg. Certain bone morphogenic proteins refined… • Osteostimulation: is a physiologic action that stimulates, enhances or accelerates the formation of bone at a host site or healing endosteal implant. • Eg, recombinant bone morphogenic protein, platelet rich plasma.
- 15. • Osteoconduction: isthe process in which synthetic and inorganic material provides a bioinert scaffolding that conducts and is compatible with bone growth. • In general alloplastic graft materials are osteoconductive. • Osteopromotive: Physical means of sealing off an anatomical site in order to prevent other tissues to interfere with osteogenesis and to direct the bone formation. • Osteogenesis: occurs when living osteoblasts are part of the bone graft as in autogenous bone transplantation.
- 16. Biologic properties ofvarious bone graft materials (caranza chapter 77)2 Source Osteoconductive osteoinductive Osteogenic Alloplast Yes No No Xenograft Yes No No Allograft Yes Yes/No No Autograft Yes yes Yes
- 17. II] Conge etal. (1978) CLASSIFIED AS Osseous Non- Osseous Autograft s Allografts Pedicle Bone swaging Free grafts Intraoral Bone coagulum Bone blend Tuberosity Extraction sites Edentulous ridge Extraoral Iliac crest Tibia Organic Collagen Dentin Cementum Coral Sclera Cartilage Inorganic (Alloplasts) POP Polymers Ca carbonates Ceramics Human bone FDBA DFDBA Resorbable TCP, HA Non-Resorbable HA, Bioglass Xenograft s
- 18. FORMS OF BONEGRAFT • 1. Non-vascularised • 2. Vascularised • 3. Cancellous • 4. Cortical • 5. Corticocancellous, has properties of both types
- 19. Cortical bone Cancellousbone Cortical bone grafts revascularise slowly. Vascularise within 2 weeks There is viable and non viable bone Here only new bone remains and the necrotic bone is removed. Here we have only viable bone. This bone graft decreases in mass and in porosity Initial increase in strength, in time mechanical strength return to normal due to osteoclastic activity and decreased osteoblastic activity Cortical bone contains pure cortex dense bone,hence it is used for weight bearing areas. Cancellous bone provides more open spaces for faster revascularisation, but it lacks mechanical strength, particularly when used for non weight bearing areas.
- 20. I Autograft • Thisrefers to bone tissue transferred from one site to another in same individual. • Common sources of bone include: – healing extraction wound – edentulous ridges – trephined from within the jaw – Newly formed bone in the wounds – osteoplasty and osteotomy
- 21. • Clinically thesegrafts can be further classified on the basis of • SITE OF ORIGIN • Ø Iliac, fibula, rib • Ø Intraoral sites(caranza)2 • PHYSICAL FORM • Ø Paste, Morsel, Chip, strip, block, segment, match stick
- 22. Osseous Coagulum • R.Earl Robinson in 1969 • A mixture of bone dust and blood. Source: Mandibular lingual ridge, exostosis, edentulous ridge, distal terminal tooth etc. Advantages: – smaller particle size – additional surface area – Ease of obtaining bone from already exposed surgical sites. • Disadvantages: – The unknown quantity, inability to aspirate, contamination
- 23. Bone Blend • Introducedby Bowers in 1972. • Cortical and Cancellous bone is procured with a trephine or rongeurs • Autoclaved amalgam capsule is used for the purpose of blending ,Slushy osseous mass (210 – 105 um) packed into bony defects • BONE SWAGING • This technique requires an edentulous area adjacent to the defect, form where the bone is pushed into contact with the root surface without fracturing the bone at its base. Elasticity of bone…
- 24. Platelet rich plasma: •This autogeneous material is sequestrated from patient’s blood and compacted by gradient density centrifugation. • It substantially increases the rate of healing. Histologically, they have revealed greater bone density after healing. • Role- increase in bone forming cells • Trigger capillary formation • Increased site debridement • Source of growth factor’s
- 25. Allografts • Allograft oralloimplant refers to bone which is harvested from one individual and transplanted into another within same species. • These bone tissue implants provide the form and matrix of bone tissue, but no viable bone cells are transplanted. • They are of three types: – Mineralized freeze-dried bone allograft (FDBA) – Demineralized freeze-dried bone allograft (DFDBA) – Frozen iliac cancellous bone & marrow
- 26. Freeze dried boneallograft FDBA • It is a human bone, harvested from fresh cadavers • It is then sterilized,freezed and dried . • It works primarily through conduction, thus over a period, it will resorb and bone graft is replaced. • Used in sinus bone grafting procedures. • Process of making: 2 Bone is washed in distilled water and ground to particle size of 500 mic to 5mm.It is then immersed in nitrogen then freeze dried, and ground to small particles( 250 – 1500 mic)
- 27. Demineralized freeze-dried bone allograft(DFDBA) •Created by removing the ca and po4 salts to take better advantage of BMP for its osteostimulatory properties. • Process of fabrication: similar initial steps as FDBA but an additional step of demineralizing the ground bone powder in 0.6N HCL or nitric acid for 6-16 hrs. • Freeze drying destroys all cells and the graft is rendered non viable. –It has the advantages of: »Decreasing antigenicity »Facilitating long term storage
- 28. III Xenografts 3 •Two available source: – Bovine bone – Natural coral • Calf bone (Boplant) • Kiel bone • Anorganic bone • Bio-Oss ® Granules, Bio-Oss ® Collagen, and Bio-Oss ® Blocks, Endobone® ,Ladec® , Bon-Apatite®, OsteoGuide TM (Anorganic Bone Mineral), OsteoGuide Collagen TM (Anorganic Bone Mineral with Collagen),Osteograf/N.
- 29. IV Synthetic bonegrafts/ Alloplasts2 CLASSIFICATION POLYMERS BIOLOGI C collagen fibrin SYNTHETIC Polylactic polyglycolic acid polymers CERAMICS Calcium phosphate Hydroxyapatite Tricalcium phosphate Calcium Sulphate METALS Titanium alloy Chrome cobalt alloy
- 30. • Bioactive Glass –Calcium salts, Phosphates- similar to teeth, bone – Sodium and silicon dioxide- bone to mineralize – Mechanism of Action: – When it comes in contact with tissue fluids- – Particle surface gets coated with hydroxycarbon apatite- – Incorporates organic ground proteins like chondroitin sulphate and GAGs – Attracts osteoblasts – rapidly form bone. – Bonds with bone and soft connective tissue
- 31. HYDROXYAPATITE 2 • Thisis a mineral substance, basically a ceramic which is similar to cortical bone in its composition. • It is inorganic, stable, non absorbable and non biodegradable. • They are osteoconductive … • Three types dense, porous and resorbable.
- 32. CALCIUM SULPHATE2 Plaster ofParis: POP (Calcium sulphate) is biocompatible and porous,thereby allowing fluid exchange, which prevents flap necrosis. • POP resorbs completely in 30 days This material can be carved into the desired shape… • ACRYLIC RESINS • A two component system • Uses include dental implants, submucosal augmentation, contour correction. • Difficulty in handling ,Problems with thermal, electrical and X-ray conductivity.
- 33. SILICONE RUBBER • Biocompatibilityand excellent physical characteristics. • Thermal stability • Basic building block is dimethylsiloxane with contributions from other organic side… • Disadvantages include low tear resistance • POLYETHENES and POLYTETRAFLUROETHYLENE (TEFLON) - Group of polymers made from ethane type monomers and include polyethylene and polypropylene. • Porous sponge form can be used in reconstruction in non load bearing areas. • POLYURETHANES • POLYAMIDE
- 34. Collagen2: • Most commonsource is bovine collagen from the Achilles tendons in the leg. • It can bond and activate platelets to form a platelet plug within the vessel. • It may also act as a scaffold for migrating cells of the epithelium
- 35. • Polycrystalline ceramics,and either in porous or dense forms. - Capo ceramics-These are are hard tissue prosthetic materials that interact with and may ultimately become an integral part of living bone. Limitation : • - Brittle, low impact resistance and relatively low strength. • Advantages: Biocompatible Lack of local systemic toxicity. They bond directly to bone without the need for porosity. CALCIUM PHOSPHATE CERAMICS
- 36. Particulate bone graft:2 •Also called bone chips • Advantages : more rapid ingrowth of blood vessels • More exposure of osteooinductive growth factors • Easier biologic remodeling • Indications: • In defects with multiple osseous walls • In dehiscence or fenestration defects • If a bone defect does not have a osseous wall to contain the graft
- 37. Monocortical block Graft:2 •Horizontal alveolar deficiencies can be best treated by it • The technique uses a cortical block of bone harvested from a remote site and used to increase the width of bone. • Intraoral sites- mandibular symphysis or ramus • Extraoral sites- iliac crest or tibia. • It is fixated to the prepared site with screws.
- 38. • A studywas done to identify which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement. • A systematic online review of a main database and manual search of relevant articles. • Implant survival was 92% for implants placed into autogenous and autogenous/composite grafts, Int J Oral Maxillofac Implants. 2008 Jan-Feb;23(1):56)
- 39. Surgical keys tobone grafting:2 Local factors: • absence of infection • soft tissue closure • space maintenance • graft immobilization • host bone vascularization • Growth factors • bone morphogenic proteins • healing time • defect size and topography • transitional prosthesis
- 40. Successful Graft: MellonigJT (1991) 7 • A) Patient Selection: • B) Material Selection: – More walls of bone -in the defect site- better a graft’s chance for success – Larger the defect -use autogenous bone – Cancellous bone over cortical bone - revascularization is rapid. – GTR membrane is not necessary for autogenous graft -but in non- autogenous revascularization occurs slowly so GTR membrane is helpful. • C) Proper flap reflection and wound stability: – Conventional full thickness – Alternative design-coronarlly repositioned flap.
- 41. • D) Revascularization: –Underlying bone that receives the graft material must exhibit several marrow spaces • E) Root debridement: – Remove completely the altered cementum and other deposits • F) Post-surgical Care: – Antibiotics – Mouthwash and oral hygiene maintenance – Periodic recall visits and regular plaque controls
- 42. Soft tissue coverageand flap design2 1)Primary soft tissue closure is a mandatory condition for the success of grafting procedures . 2)Primary incision- keratinized tissue 3) The blood supply to the reflected flap-maintained 4)Soft tissue flap design should have the margins of the wound over host bone rather than on the graft or barrier membrane 5)Primary wound closure should be without tension 6)The margins distal to the elevated flap should have minimal reflection
- 43. Choosing a graftmaterial: • Five wall defects- • Four wall defects-. • Three wall defects- allogenic bone blocks around the margins,or allogenic putty. • Two wall defects- particulate autogenous bone graft with a barrier membrane secured in place with pins or screws. • One wall defects- referred to as knife edge defects and require a two stage treatment with bone grafting techniques. Alloplasts are used
- 44. The classification ofbone defects: (Lindhe) • Class I – Extraction sockets • A flap is raised to allow easy access to the site and implant inserted • A membrane supporting material is adapted to support the membrane • It is placed into the space between the walls of the socket and implant surface. • Subsequently the membrane is adapted to cover the supporting material and a narrow zone of the adjacent bone and the flap is adapted and sutured.
- 45. • Class IIand III – Dehisence defects • Procedure: • After the flap is raised the implant is inserted. • A membrane is placed and adapted to cover the supporting material and the defect. • The membrane is to be fixed in place to provide stability necessary for bone to form. • Implant is allowed for submerged or transmucosal healing.
- 46. • Class IV-Horizontal defects. The autogenous block transplant-the gold standard(Becker et al 1994) Disadvantages of intraoral harvesting procedures: • limited availability of bone graft volume, • complications including altered sensations • wound dehiscence • infection Advantages: • large scientific and clinical documentation • handling properties,
- 47. Class V- VerticalDefects • Include situations where the remaining bone height is too small… • The same procedure as for IV with the exception that the bone block is partially or fully placed on the ridge in order to gain bone in a vertical direction. • Flap adaptation is more difficult due to increased volume intended for regeneration which intends to be covered by the flap.
- 48. Guided tissue regeneration5: •The terms ‘‘guided bone regeneration’’ and ‘‘guided tissue regeneration’’ (GTR) often are used synonymously and rather inappropriately. • GTR deals with the regeneration of the supporting periodontal apparatus, including cementum, periodontal ligament, and alveolar bone, • Whereas GBR refers to the promotion of bone formation • Principle that use barrier membranes for space maintenance over a defect, promoting the ingrowth of osteogenic cells and preventing migration of undesired cells from the overlying soft tissues into the wound. Bone Augmentation Techniques;J Periodontol • March 2007, McAllister, Haghighat
- 49. Graft + GTRMembrane The use of physical barriers to retard or prevent apical migration of epithelium as well as exclude gingival connective tissue from the the healing wound form the basis of GTR(Gottlow et al 1986)
- 50. Guided bone regeneration5: •Defects associated with dental implants may be divided into several categories: • For isolated localized defects or defects associated with implant placement • Dehiscence defects- most common. Defect of cortical bone resulting from trauma, bone resoption or tooth removal • Residual intraosseous defects- incomplete healing of the alveolus leading to exposure of threads • Fenestration defects- anterior maxilla • Extraction socket defects
- 51. Membranes5: • Criteria regardingmembranes have been formulated(Hardwick et al 1994)5 • Biocompatibility • cell occlusiveness • intergration by host tissues • clinical manageability • space making function • Additional criteria for bioresorable and biodegradable are (Gottlow 1993) • tissue reactions should be minimal • these reactions should be reversible • they should not negatively influence the regeneration of the desired tissues.
- 52. Nonresorbable membranes • Polytetrafluoroetylene(PTFE), Expanded PTFE(e-PTFE or teflon), Titanium-reinforced membranes Expanded PTFE is characterized as a polymer with high stability in biologic systems… • They are available in various sizes and shapes to custom fit around teeth and osseous defects.2 • Adv2: 1. Ability to maintain separation of tissues • Unless exposed it can remain in place for several months to years. • Disadv2: 1. If it becomes exposed it will not heal
- 53. • Bioresorbable membranes2,3 •ePTFE materials is that they are non-resorbable and therefore have to be removed during a second surgical procedure. • Made of either collagen or polyglycolide and/or polylactic acid. Advantages • No need for membrane removal surgery • Better cost-effectiveness • Decreased patient morbidity Disadvantages • Uncontrolled duration of barrier function • Resorption process possibly interfering with wound healing and bone regeneration • Mild inflammatory reaction may interfere with osteogenesis • Are quite piable- collapse into the defect area. Bone augmentation by means of barrier membranes Christoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33,
- 54. • Various reasonsfor the generally lower defect fill with bioresorbable membranes as compared to nonbioresorbable membranes include: • the better space-making capacity of nonbioresorbable; • controlled time of barrier function; • lack of a resorption process and lack of the generation of resorption products that negatively affect bone formation; • longer experience with nonbioresorbable membranes In summary, the nonbioresorbable membranes allow for slightly more bone regeneration than bioresorbable ones. Bone augmentation by means of barrier membranes Christoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33, 2003, 36–53
- 56. Maxillary sinus bonegrafting10 • Tantum was first to perform sinus augmentation in mid 1970’s. • Boyne and james were the first to report their 4-yr experience with autogeneous bone placed in the sinus. • Assessment of maxillary bone Parel classification10 • Class I: Alveolar bone height normal – patient with missing only teeth alveolus is intact. Best treated with a fixed prosthesis or requires an alveolectomy or osteotomy to create room for a removable prosthesis. • Class II: Moderate alveolar bone resorption- patient needs restoration of alveolus either with denture flange or bone graft. • Class III: Severe alveolar bone resorption- all alveolar bone resorbed, patient requires restoration with denture material or bone graft. Patient needs extensive grafting to provide a stable prosthesis mechanically.
- 57. Misch treatment options:12 •Subantral option one: Conventional implant placement • When sufficient bone height is available to permit the placement of implant following a usual surgical protocol. The quality of bone commonly is D3 or D4 bone, bone compaction to prepare the site is common. • Subantral option two: sinus lift and simultaneous implant placement • When 10 to 12mm of vertical bone is present (2mm less than SA-1). The antral floor is elevated through the implant osteotomy 0 to 2mm, it modifies the floor of the maxillary sinus.
- 58. • Subantral optionthree: Sinus graft with immediate or delayed endosteal implant placement Is indicated when less than 5mm of vertical bone and sufficient width are present between the antral floor and the crest of the ridge. • The author has chosen residual height of 5mm because: Can be considered sufficient to allow primary stability placed at the same time of sinus graft procedure May allow the use of alloplastic materials because adequate amounts of bone may be harvested from the tuberosity • Subantral option four: sinus graft healing and extended delay of implant insertion • When less than 5mm remains between the crest and floor of sinus.
- 59. Direct sinus liftprocedure • The sinus surgery is done first. • Design of the incision depends upon the width of the attached gingiva. • After the membrane is elevated and the lateral maxillary wall rotated medially, the thickness of the alveolus is accessed and the proper bone graft can be harvested
- 60. • After thelateral maxillary wall is exposed a 3mm diameter round bur or no.8 round diamond stone in high speed impactair handpiece, • Make a horizontal line parallel to and at the level of the antral floor in the lateral cortex of the maxilla. • Create the groove by gentle brushing of the bone so that it barely penetrates the cortical plate
- 61. • As thisis done the superior line with its remaining attachment to the flap becomes a hinge. • After the door is pressed inward for 4 to 5 mm, reflect the membrane from the bony floor of the sinus.
- 63. • If thesinus floor is thin(1-2mm)… • Bone harvesting
- 64. Grafting to improveridge dimension for the accomadation of implants Anterior mandible width deficiencies11: • Alveoplasty: knife edged ridges or sharp spicules can be removed before making implant osteotomies.. • Monocortical bone grafting: affixing a block of bone can augment the width and height of the anterior mandibular ridge. • This may be obtained from a bank or can be autogeneous bone, mandibular symphsis being the ideal site. • The graft is stabilised in place with titanium screws.
- 65. • Anterior mandibleheight deficiencies: • Monocortical grafts • Inferior border augmentation: • If a patient has extremely atrophied mandible(1 to 6mm thick). Autogeneous bone from iliac crest is taken. • A mesh prosthesis with graft material is affixed to inferior border with self tapping screws. An titanium inferior border mortise-form mesh is filled with iliac crest marrow and is harvested.
- 66. • Posterior mandibularheight and width deficiencies: • Monocortical bone grafting: symphyseal monocortical block inlays may be used in regions posterior to mental foramina. Mandibular neuroplasty and nerve management: • To add additional vertical height: make an incision at the crest of the ridge from the retromolar pad anteriorly to most distal tooth in position. Use a sponge to elevate the mucoperiosteum to the level of the mental foramen.
- 67. Anterior maxillary widthdeficiencies: • Monocortical bone grafting • Expansion by longitudinal splitting: Make a crestal incision and reflect the mucoperiosteum. Refine the lower border of the ridge with a ronguer and bone files and allow the entry of first no.1/2 round and then no.699 high speed bur. Make perforations using these bur to the full depth and connect them into a groove, this is followed by placement of spatula osteotome into the osteotomy.
- 68. Bone Augmentation Techniques,J Periodontol • March 2007, vol 78;3:386 McAllister, Haghighat A staged ridge-expansion technique. Vertical and horizontal corticotomies are made, following a partial-thickness flap elevation, a conventional ridge-expansion is performed. A saggital saw is used to perform the crestal corticotomy. Uncovery at 6 months was done following the placement of the implant.
- 69. Anterior maxillary heightdeficiencies: • 1. Block grafting • 2.Nasal floor elevation: The pyriform apertures can be exposed by means of an intraoral approach. • The floor of the nose either unilaterally or bilaterally may be grafted for upto 10mm so that apical extensions of implants of sufficient length can be enclosed in bone with only modest impingement of the nasal floor.
- 70. Immediate implant placement(BDJ 2006.201;4:199) • While extraction, care must be exercised not to luxate the tooth buccal- lingual.. • A direction indicator should be used to verify the correct angulation and trajectory of the proposed implant.
- 72. • The benefitsof immediate placement are11: • Combining integration of the implant with mineralization of the socket shortens healing time. • Preservation of ridge morphology and dimension is encouraged by the presence of an implant • Position and angulation of the implant is simpler because the recently removed tooth indicates this geometry and the walls of the alveolus serves as guides in directing the osteotomy.
- 73. SOCKET PRESERVATION: • Itimplies that placement of varying implantable materials within the sockets alone or with barrier membranes maintains socket anatomy. • Ridge width and height dimensions were preserved with bone graft materials. • The study suggests that treatment of extraction sites with membranes made of glycolide and lactide polymers is valuable in preserving alveolar bone in extraction sockets, minimize crestal bone loss and preventing ridge defects.14 To preserve the extraction socket architecture and to accelerate the timeline to final implant restoration, the technique of immediate implant placement at the time of extraction often is proposed.
- 74. FIRST STAGE SURGERY8 •A surgical splint can be used to determine proposed fixture locations and serve as a guide. • The first stage surgery consists of following events (Adell et al 1981,1985; Albrektsson et al., 1986; Lekholm,1983) and Surgical technique for implant installation( BDJ OCT 1999, 187; 8: 415)9 : 1. Anatomical consideration 2. Surgical incision of gingival and mucoperiosteal flap reflection 3. Drilling and countersinking procedure 4. Tapping procedure 5. Fixture installation and cover screw placement 6. Implant placement 7. Soft tissue re- adaptation and suture procedure
- 75. 1.Anatomical considerations: • Fullyconversant with all anatomical structures that they are likely to encounter • In the maxilla: air sinuses, nasopalatine canal, floor of nose and nasal spine, palatine and pterygoid vessels. • In the mandible: sublingual vessels, mental nerve, inferior dental nerve, incisive branch of inferior dental nerve, genial tubercles. • Teeth: position, length, angulation of roots adjacent to implant sites. • Available bone: ridge morphology, bone density, localized deformities
- 76. 2. Surgical incisionof gingival and mucoperiosteal flap reflection • Make the surgical incision with a no.15 blade and cut through mucosal tissue along the same line. • Dissect the muscle fibres carefully with the no.15 blade • The periosteum is cut carefully 5mm below the crestal ridge ,When incision is difficult, lengthen the incision into the periosteum toward the alveolar crest. • Expose the alveolar crest using the dissector to remove any fibrous adhesions. • Locate any anatomical landmarks or foramen if any.
- 77. • Flap design:There are many different flap designs for implant surgery. • In practically all situations a mid-crestal incision can be employed. Access and elevation of flaps can usually be improved by additional use of vertical releasing incisions. 3. Drilling and Countersinking procedures • Guide drill • Use of any of the drilling instruments requires copious saline irrigation. • Use the guide drill to mark the proposed fixture sites and penetrate the cortical plate into spongy bone.
- 78. • Use of2mm twist drill • It is used to enlarged the fixture site. Each fixture site is marked using the guide drill and enlarged sequentially with 2mm twist drill. • A direction indicator into the prepared site. At this stage the direction of the fixture site can be changed using the guide drill and side cutting drills.
- 79. • Use ofpilot drill • It is used to enlarge the site from 2-3mm diameter. Do not exceed the mark on the pilot drill indicating depth since it may result in thermal damage. • Inferior aspect- engage the 2mm prepared site and superior portion begins the enlargement of the site. 18 Use of 3mm twist drill • This procedure is important for preparing the fixture site to the proper depth. • Used to prepare the bone to its final dimensions. • Use of countersink • It is done after enlarging the site to 3mm to achieve fixture and cover height level with the alveolar bone. Used to create a shelf in the prepared bony site. Crestal module…
- 80. Surgical preparation ofthe bone • It is essential not to allow the bone to be heated above 47deg cent during preparation as this will cause bone cell death and prevent osseointegration. • This problem may be avoided by: • Using sharp drills • Employing incremental drilling procedure with increasing diameter drills • Avoidance of excessive speed (no more than 2000rpm) and pressure on the drills- it should be withdrawn from the bone frequently to allow the bone swarf to clear • Using copious sterile saline irrigation.
- 81. 4.Tapping procedure • Itis first in series of slow speed bone preparation instruments • It is utilized to thread the bone prior to implant placement • In harder bone type tapping is done, using the slow speed handpiece or use the cylinder wrench to tap manually
- 82. Number of drillsused to prepare implant osteotomy corresponds to bone density, Carl E Misch • D1 bone- requires 4 drills, a crestal bone drill and a tap •D2 bone- standard drill protocol is used •D3-requires only 3 drills and no crestal drill or tap •D4- requires 2 drills and osteotomes to compress the residual bone making it more dense
- 83. 5.Fixture installation andcover screw placement • A fixture mount is connected to the fixture using the open ended wrench and long screwdriver. • The fixture mount is connected to handpiece the implant is installed without irrigation until the horizontal hole of the fixture has threaded into the site and is not visible. • After using slow speed motor for fixture installation, Use the cylinder wrench for final tightening by holding the thumb against the top of the wrench and the forefinger around the jawbone.
- 84. • 6.Implant placement •Ideally it should be placed such that: • It is within bone along its entire length. • It does not damage adjacent structures • It is located directly apical to the tooth it is replacing and not in an embrasure space • The angulation of the implant is consistent with the design of the restoration • The top of the implant is placed sufficiently far under the mucosa to allow a good emergence profile of the prosthesis. This is often achieved by countersinking the head of the implant.
- 85. 7.Soft tissue adaptationand suture procedures Suture the midline initially then continue from the distal borders of the surgical site towards the midline. The suture should not be placed directly over the cover screw to avoid risks of fistula formation. Incision is closed in position buccal to implant placed
- 86. Post operative care •After implant surgeries the patients should be warned to expect: • Some swelling and possibly bruising • Some discomfort which can be controlled with oral analgesics • Some transitory disturbance in sensation if surgery has been close to nerve. • In most circumstances not to wear denture over the surgical site for atleast 1 week. • To use analgesics and ice packs to reduce swelling and pain • To keep the area clean by using chlorhexidine mouthwash 0.2% for 1 min twice daily. • Not to smoke. Ideally patients should stop smoking for some weeks before the surgery and for as long as possible therafter.(BDJ, VOL187,NO. 8, OCT 23, 1999, 419)
- 87. FUTURE BONE AUGMENTATION APPROACHES •BMPs are differentiation factors that are part of the transforming growth factor superfamily. • Two of these proteins, BMP-2 and -7 (or osteogenic protein-1), have been cloned, studied extensively, and show promise for intraoral applications Human studies demonstrated product safety with BMP-2 in ridge preservation and sinus augmentation applications. • Platelet derived growth factor (PDGF) has received the most attention for intraoral use • Gene therapy is a relatively new therapeutic modality based on the potential for delivery of altered genetic material to the cell. Localized gene therapy can be used to increase the concentration of desired growth or differentiation factors to enhance the regenerative response Bone Augmentation Techniques,Bradley S. McAllister and Kamran Haghighat, J Periodontol • March 2007, vol 78;3:386
- 88. CONCLUSION • Improvements ofthe techniques seem to be a reliable way of increasing oral implant success. • By using proper techniques and newer graft materials according to the demanding situations, implant dentistry is bright we can make it brighter!
- 89. REFERENCES 1. Implants indentistry , Michael s block, John N kent, Luis R Guerra 2. Contemporary implant dentistry,3rd editin, Carl e misch 3. Clinical practice of mainstream implant dentistry, bone enhancement section 3 4. Bone, ARUN Garg 5. Clinical Periodontology and Implant Dentistry, 5th edition, Jan Lindhe 6. Membrane barriers for guided tissue regeneration, Arun K Garg, 7. Periodontal Therapy: Clinical approaches and evidence of success, Vol. 1, Myron Nevins and James Mellonig. 8. Osseointegration and full mouth rehabilitation, Sumaiya Hobo
- 90. 9. Basic ImplantSurgery , Richard Pslmer, paul parmer, peter Floyd, BDJ ,oct 1999; 187:8:415 10. Maxillary sinus grafting, Michael s Block, John n Kent, pg 478 11.Atlas of oral implantology, A Norman Cranin 2nd edition. 12 .Contemporary implant dentistry, Carl E misch, 3rd edition 13. Biology, harvesting, grafting for dental implants, rationale and clinical applications, Arun K Garg 14.Immediate implant placement: treatment planning and surgical steps for successful outcomes, British Dental Journal; vol 201; no 4; aug 26, 2006:199-205.
- 91. 15.Bone Augmentation Techniques,J Periodontol • March 2007, vol 78;3:386 McAllister, Haghighat 16. Bone augmentation by means of barrier membranes,Christoph H. F. Hammerle & Ronald E. Jung , Periodontology 2000, Vol. 33, 2003, 36–53 17. Implant dentistry, Palmer 1st edition 18. A colour atlas:The branemark system of oral reconstruction, Richard A
Editor's Notes
- #6 …applied, heals, becomes incorporated, revascularizes and eventually assumes the form desired. and the results were measured primarily by the graft’s ability to withstand the mechanical stresses that surrounded them Different forms of bone grafts vary on the basis of the function that they must perform.
- #7 A graft is a substance, foreign to the region of the body in which it is placed, which is used to replace, augment or fill a defect created by surgery, trauma, disease and developmental deficiency. Graft is a living tissue, transplanted to a different site, that continues to live and function in the new environment. Auto graft : Bone graft transplanted from one site to another from patients own body. Allograft : Bone transplanted from one individual to another genetically unrelated individual of same species. Xenograft / Heterograft : Bone taken from another species. These can be both cancellous or cortical Isograft : Bone graft transplanted from one person to another genetically related individual of same species. Composite : Bone grafts are made partly allograft or heterograft and partly autograft. Alloplast: Synthetic or inorganic implant materials which are used as substitutes for bone grafts.
- #9 It was later done by Ham and Gorden in 1952 and Hancock 1963. To freeze dried autogenous grafts, allografts, inorganic bone and its substitutes.
- #14 …with advent of growth factors to augment the osteogenic potential of current or future graft materials.
- #15 …differentiation of pluripotential stem cells freely circulating in the blood. BMP’s signal stem cells to differentiate into osteoblasts to produce bone. They stimulate the formation of osteoprogenitors from the defect and differentiate into osteoblasts and begin new bone formation.
- #16 Conducti0n-They do not enhance or inhibit bone formation. They guide the path and progress of bone formation. Osteogenesis-They form new centres of ossification and contribute to the total capacity for bone formation.
- #18 Ref --, 14
- #20 1.need to open, by the osteoclastic activity, the existing Volkmanns canals and Haversian system. It may also be due to smaller no of endosteal cells available for the end to end anestamosis. 3. . The no. of viable cells are more also because of ability of more cells to be nourished by diffusion from surrounding host. 4.thus it is weakened by 50% from 6 weeks to 6 months to 2 years following grafting, the mechanical strength is equal to normal bone. It is usually layered and the only open space for revascularisation is that of nutrient blood vessels.
- #22 Intraoral- edentulous sites, maxillary tuberosity, mandibular ramus, symphsis, extraction sites. Max vol of bone – post iliac crest-140ml, ant iliac- 70, tibial plateau- 20 to 40ml, asc ramus- 5 to 10ml, ant mand- 5 ml, tuberosity- 2ml. Int<extraoral sire
- #23 Smaller-more certain resorption and replacement by bone. Surface area- interaction of cellular and vascular elements. Bone is removed with a carbide bur #6 or #8 at speeds between 5000 and 30,000 rpm, placed in a sterile dappen dish or amalgam cloth, and used to fill the defect. Disadv-during collection process for the fear of aspirating graft material. Inability to aspirate Complications of salivary contamination and bleeding.
- #24 To overcome the disadvantages of the osseous coagulum bone blend technique was Bone with greater cancellous composition is more flexible. Bone without adequate cancellous material tends to fracture from the alveolus. Technically difficult. Cartilage and sclera- pd defects
- #25 The beneficial ingredients are platelet based growth factor and a beta transforming growth factor. Secreted by act macrophages, stored in platelets and bone matrix Cha of wound hormones
- #26 This is the principle alternative to autogenous bone
- #27 Removes more than 95%of the water content from the bone. It preserves the 3 major specimen character: Size Solubility Chemical Integrity Freeze drying destroys all cells and the graft is rendered non viable. Calcium, phosphate salts are retained to support the organic and inorganic matrices.3 The organic portion contains the BMP’s found in the cortical bone and inorganic portion serves as a mineral source of scaffolding for bone formation. It is essentially osteoconductive because the BMP’s are released too slow and in minute quantities to be effective.
- #28 Has high probability of transferring infections. Irradiation for sterilization may render it unable to stimulate bone formation. The BMP are not acid soluble but ca Po4 salts are acid soluble therefore demineralization exposes the BMP’s more readily. Hence more bone induction. The nonsoluble BMP’s are available in the local environment earlier than with FDBA. Freeze drying- preserves the 3 major specimen character: Size Solubility Chemical Integrity
- #29 . The genetic transplantation differences between human tissue and that of other species (e.g., bovine), are such that the fate of such grafts is their eventual sequestration without any new bone formation. Calf bone- treated by detergent extraction, sterilized and freeze dried has been used for the treatment of osseous defects. Kiel- is calf or ox bone denatured with 20% hydrogen peroxide, dried with acetone, and sterilized with ethylene oxide. Anorganic-is ox bone from which the organic material has been extracted by means of ethylenediamine, it is then sterilized by autoclaving. ANORGANIC BOVINE BONE (ABB):
- #31 Powder+prefilled diluent- moulable plastic mass- desired shape- adhesive mixture X sutures, inf reaction Capset kit
- #32 Dense-When prepared at high temperature (sintered), hydroxyapatite is nonresorbable, nonporous, dense, and has a larger crystal size (Klein CP et al, 1983).,periograf, calcite. Obtund a space and maintain bone contour Porous-It has a pore size of 190 to 200 um, which allows bone in growth (West TL et al, 1985) into the pores and ultimately within the lesion itself (Kenny EB et al, 1986). , interpore Resorable-Its reported advantage is the slow resorption rate, allowing it to act as a mineral reservoir at the same time acting as a scaffold for bone replacement The material has also been used for endosseous implants and for sinus augmentation,osteograf
- #33 …and provides a uniform distribution of large interconnecting pores from 100 to 300 microns in size .Progressive invasion and replacement of the implant with bone were observed. Acrylic resin is available as; a powder of small PMMA spheres and beads and a liquid monomer. The polymerization is strongly exothermic (max. Temp. 120oC).
- #34 Oxidative stability chains i.e., Vinyl and Phenyl condensation polymerization produces a high molecular weight molecule that has a highly polar Si-O-Si backbone. Tetrafluoroethylene gas at high temperature and pressure. - Non carcinogenic, resistant to corrosion, non adherent and can be sterilized. - Available in sheet that are 1.245 mm thick .Teflon-Used for repair of orbital floor fractures. Also used to correct facial and skull defects, reconstructing the external ear, the trachea and rebasing the vocal folds. Polyurethanes-Implanted in the form of rigid foams for bone replacement and as bone adhesions. Polyamide- in facial augmentation
- #35 Collagen is an intergral part of the soft tissues with the chemotactic and hemostatic properties.
- #39 from refered journals were performed between 1980 and 2005. Updates and additions were made from September 2004 to May 2005. 93.3% for implants placed into allogeneic/nonautogenous composite grafts, 81% for implants placed into alloplast and alloplast/xenograft materials, and 95.6% for implants placed into xenograft materials alone.
- #40 INCISION line opening most postoper compli. Guidelines- incisoin on ker tisssue- decreses bleeding, severs small blood vessels, dec postoper edema. Space mainteneane- space- anatomical size and contour desired for augmentation Mainteneance- fact apace must exist long enough for bone to fill Tran pros- soft tis healing, immob, before fab final prsothesis
- #41 Pt selection-Motivate for maintenance Keep up all appointments
- #42 -good blood supply -prompt revascularization -to ensure survival of undifferentiated mesenchymal cells and osteoblast at the site. If the host site is lined with cortical bone, this must be penetrated with round bur to open into the underlying marrow.
- #43 Healing primary intention Requires minimal soft tissue collagen formation and soft tissue remodeling Minimizes postoperative discomfort Ker tis-decreses bleeding, severs small blood vessels, dec postoper edema. Necessary step for predictable bone regeneration
- #44 Five wall-extraction sites with five thick bony walls intact may not require any grafting there is a large amount of interseptal bone present. 4 wall-a site that is missing one or two socket walls or that has one or more extremely thin walls, bone grafting is advised at the time of extraction. 3-If not available alllogenic bone putty or a combination of bone putty and autogeneous bone can be used. Three-a site that has lost two walls or that has two or more extremely thin walls. …the clinician places the block in the appropriate position over and around the defect and then uses the allogenic bone putty to fill the defect to motor the voids and to seal the margins. 2-Primary stability is of paramount importance to the result and generally be achieved by appropriately repositioning the reflected periosteum. 1-Membranes are generally used to maximize the predictability of the graft. There is a 4-6 month waiting period before placing implants.
- #45 is intended as a guideline for choosing the best techniques and materials for grafting at implant sites.In esthetic zone it may be necessary to augment the bone beyond the labial tissue contour.
- #46 May range from a very small lack of marginal bone to large areas of denuded implant surfaces. …with the aim of promoting bone formation for bone integration of the implant and obtaining a natural appearance of the bone and soft tissue contours. The esthetic result, as well as aspects of health and function is important.
- #47 Intraoraol sites are preffered for localized bone defects, the common donar sites being the chin, retromolar region in the mandible. During second surgical intervention after 4-9 months, the result of the augmentation procedure can be seen and implants placed. stabilization of area intended for regeneration due to possibility of securing the grafts in place by metal screws, optimal biologic properties
- #48 …for proper anchorage of implants, where unfavourable crown:implant ratios will result and where unfavoourable esthetic outcomes are expected from the lack of remaining hard and soft tissues. With a narrow ridge, splitting the alveolar bone longitudinally, using chisels, osteotomes, or piezosurgical devices,225 can be performed to increase the horizontal ridge width, provided the buccal and lingual cortical plates are not fused and some intervening cancellous bone is present. With adequate vascularity and stabilization of the mobile bone segment, together with sufficient interpositional bone grafting and soft tissue protection, a comparable result to alternate techniques can be obtained.223,224 A 5-year study226 evaluating 449 implants placed in maxillary ridges expanded by the ridge split technique revealed a survival rate of 97%, which is consistent with placement in native bone. Recently, a modified two-phase approach to the ridge split technique was introduced that aims at minimizing the risk for unfavorable fractures of the segment in less flexible bone, as well as maintaining the segment vascularity during its expansion (Fig. 6). In the first surgery, a full-thickness mucoperiosteal flap is elevated on the buccal aspect of the ridge. A saw, bur, or piezosurgical device is used to perform the apical horizontal and proximal and distal vertical corticotomies. The crestal corticotomy can be made at the primary or secondary operation. The second surgery, a month later, involves the splitting and expansion of the ridge using osteotomes. At this stage, split-thickness buccal mucoperiosteal flap is elevated to preserve the vascularity of the buccal cortical plate. Implants can be placed in the space created between Figure 5. A) Vertical and horizontal ridge defect at 3 months following extraction of traumatized teeth #7 and #8. B) Adaptation and stabilization of a symphyseal autologous block graft. C) Placement of a combination of particulate xenograft and autologous bone graft to achieve fill of the defect. D) Placement of a collagen membrane over the grafted defect. E) Six months postoperative view of the reconstructed ridge. F) Implant placement revealed a stable reconstructed ridge.
- #49 The concept of GBR was described first in 1959 when cell-occlusive membranes were employed for spinal fusions. Protection of a blood clot in the defect and exclusion of gingival connective tissue and provision of a secluded space into which osteogenic cell from the bone can migrate are essential for a successful outcome.
- #53 ...It resists breakdown by host and and by microbes and does not elicit immunologic reactions. 2.Exposed membranes become contaminated with oral bacteria leading to infection and bone loss
- #54 With regard to patient morbidity and psychological stress, risk of tissue damage, and cost versus benefits, the replacement of non-resorbable by bioresorbable membranes is highly desirable. Hence, recent experimental research in GBR has aimed at developing bioresorbable barrier membranes for application in the clinic Other membranes are cellulose filters, collagen membranes,polylactic acid, poluglycolic acid and polylactic acid, synthetic liquid polymer(atisorb), polyglactin, calcium sulfate, acelular dermal allografts, oxidized cellulose mesh.6 Bioresorbable membranes that are commercially available at present are not capable of maintaining adequate space unless the defect morphology is very favorable (77). Even if the membranes initially seem able to maintain space, they generally lose their mechanical strength soon after implantation into the tissues. Only in situations where the bony borders of the defects adequately support the membrane have favorable results been reported. When defects are not space making by themselves, failure of bone regeneration results (82, 126). Therefore, they need to be supported in one way or another. Bioresorbable membranes that are commercially available at present are not capable of maintaining adequate space unless the defect morphology is very favorable (77). Even if the membranes initially seem able to maintain space, they generally lose their mechanical strength soon after implantation into the tissues. Only in situations where the bony borders of the defects adequately support the membrane have favorable results been reported. When defects are not space making by themselves, failure of bone regeneration results (82, 126). Therefore, they need to be supported in one way or another.
- #57 Maxillary post edentulous region presents many unique and challenging conditions in implant dentistry. Most notewrthy surgical method include grafting the sinus to overcome the problem of reduced vertical available bone has become popular and predictable procedure over the last decades. This classification play a role in the decision making process when determining whether to onlay or inlay graft material.
- #58 Osteotomy and sinus lift(SA-2) A flat end or cupped shaped osteotome of the same diameter as the final osteotomy is selected. The osteotome is inserted and tapped firmly in 0.5 to 1 mm increments beyond the osteotomy until reaching its final vertical position upto 2mm beyond the prepared implant osteotomy . A slow elevation of the floor is less likely to tear the mucosa. This surgical approach compresses the bone below the antrum, causes greenstick fracture in the antral floor and slowly elevates the unprepared bone and sinus membrane over the broad based osteotome.
- #59 A lateral wall approach is performed just superior to the residual bone, after the lateral access window and membrane rotated in and upward to a superior position a mixture of autogeneous bone, alloplast/ or allograft material is placed in the space previously occupied by the sinus. The inadequate bone height decreases the predictable placement of an implant at the same time as the graft. Therefore fewer bony wall, less vascular bed, larger bone graft all mandate a longer healing period and slight altered surgical approach. It provides better surgical access as the antral floor is closerand the access may even be designed in zygomatic arch. The elevation is 11 to 16mm from the sinus floor, because less autogeneous bone is harvested an additional harvest site may be required.
- #60 If the attached gingiva is wide a curved incision is made in vestibule extending down to mucogingival junction for the sinus bone grafting and a separate crestal incision is made for placement of implants.Usually the attached gingiva is narrow hence a crestal or palatal incision is made for placement of both the graft and the implants. The crestal incision combined with vertical incisions provides access to the crest and the lateral maxillary wall.
- #61 . The groove should run the full anteroposterior dimension of the antrum. Place a second line parallel to the first one, 15mm above it. Connect these two horizontal lines with vertical ones at either end, again using the diamond in a gentle brushing motion. At this juncture, the outline of a rectangle is plainly visible. Round these two lower corners so that they will not tear the sinus membrane. Use a mallet and blunt end of an orangewood stick to gently mobilize the plate of bone inward
- #62 Elevate the lining ahead of the bone trapdoor as it is moved further inwardly, In such a manner the rotated maxillary wall when elevated to a horizontal position, becomes the new floor of the sinus and the antral membrane is advanced in folds above it. The sinus membrane, which is plentiful because it was elevated in folds, may be sutured to bone using these bur holes as sites of fixation11.
- #63 Once the sinus membrane has been elevated the surgical guide is placed and the implant sites are prepared.
- #64 …the surgeon may elect to place a solid block graft or place the graft without implant placement , returning for implant placement after 6months of healing. Iliac crest bone harvest, rib,tuberosity, Intraoral bone harvest: maxillary tuberosity harvesting, Mandibular symphysis, anterior border of the mandible
- #65 Make the incisions at the ridge crest and with rosette and fissure burs, ronguers, bone files perform reduction, recontouring, smoothing of the bone with precision
- #67 The emerging neurovascular bundle will be seen protect it with a elevator or other small retractor. Brush away with a bur the cortical bone overlying the nerve then with a blunt nerve hook, lift the bundle from its canal. The nerveless mandible has been created which is now available for placing implants. implants can be placed the full distance to the inferior border. Lay the displaced nerve bundle in position.
- #68 Tap it with a mallet to the planned depths in a step wise methodical pattern. Use the osteotome as a lever, gently expanding both labial and palatal walls. Firmly tap particulate DFDB graft material with patients blood into the newly created osteotomy. Cover the area with vicryl mesh the margins tucked beneath the flaps. Six months later upon reexposure , its expanded dimensions are evident. The new widths permit the placement of implants.
- #71 Process begins with extraction of hopeless tooth and socket grafting with use of barrier membrane to achieve good biomechanics and esthetics. Excessive force in this direction can damage the buccal plate. Teeth to be removed and implants placed can be assessed using either an open flapped approach or with minimally invasive technique.The reasons of extraction can include insufficient crown to root ratios, insufficient root length, insufficient remaining periodontal attachment levels, unrestorable caries, root fractures with large endodontic posts, root resorption, questionable teeth of endodontic retreatment. . In the aesthetic zone, the implant head should be a minimum of 3mm apical to an imaginary line connecting CEJ of adjacent teeth and apical to interproximal and crestal bone. Interproximal papillae adjacent to implant can be adapted with interrupted sutures under minimal tension. interface.The provisional restoration should have an ovate pontic to support the adjacent tissues and help preserve soft tissue anatomy adjacent to the implant.
- #72 Place bone substitute material around the implant which encourages a more intimate final osseous
- #74 Is a relatively new term There is evidence that resorbable barriers without grafting reduces the alveolar ridge resorption after tooth extraction. There were significantly less loss of alveolar bone height, more internal socket bone fill and less horizontal resorption. In the anterior maxilla, where the buccal plate often is extremely thin and friable, consistent bone resorption is found after extraction. To minimize bone resorption, less traumatic extraction techniques with socket augmentation, using a variety of particulate bone graft materials with and without membrane barriers.
- #76 Proper asepsis has to be followed prior to and during the surgery. Prior to surgery all the equipments, instruments, components and instruments along with the drilling motor units and vacuum equipment should be checked properly. When performing surgery on a patient’s mandible the lower lip is retracted and using the dissector the incision is marked 10.0mm away from the crestal ridge. All incisions are made through the periosteum down to bone. Full thickness mucoperiosteal flaps are raised carefully to expose the entire extent of the edentulous ridge where the implants are to be placed. The bone height may appear inadeaquate in radiographs but the buccolingual width may be insufficient due to the resorptive pattern after extractions. Remove the crestal bone to create an adequate width and double check the fixture length needed prior to insertion.
- #78 Each system follows different sequence of their drills,this is the basic system gven by branemark’s system Guide drill- 1st drill used in bone preperartion, designed to penetrate the cortical layer only.
- #79 During drilling the bur is moved in an up and down motion into the prepared site to help remove residual bone and maintain adequate cooling. Side cutting drills- change the angulation after checking with direction indicator The orientation and length of fixture is to be established initially with this drill
- #80 However, countersink should not exceed further than half the thickness of marginal cortical bone. Each site should be checked with the depth gauge to establish final fixture length. Wider crestal module designs- increase the diameter only in this region If no marginal cortical bone, no countersink drill. Step allows the placement of the superior aspect of the fixture crestally or subcrestally When the bone quality is soft and bone density is low, change in the sequence of drill contersink may nt be needed Used bcoz wider crestmod design- below te bone, increase diameter only on this region
- #81 Recommendations by Erickson R.A. Slow speed Graded series Adequate cooling Overheating avoided Bone cutting speed of less than 2000 rpm Tapping at a speed of 15 rpm with irrigation Using sharp drills
- #82 Speed 30 rpm misch, branemark- 15 to 20 rpm Very dense bone- tap in d entire imp height D2- bone tap only in section Tapping- increases the %ae of bone imp contact.
- #83 D2- use of bone tap depends upon the final osteotomy size, implant body size, depth of thread, shape of thread. D3- no crestal drill because the thin crestal cortical bone provides initial stabilty In poor bone quality the site can be made relatively smaller to produce compression which will improve initial stability. In dense bone the site has to closely match the size of the implant.
- #84 The surgical assistant handles the sterile fixture package and breaks the glass ampule in half. Be certain that inner hexagonal surface fits properly over the fixture head
- #85 There is sufficient vertical space above the implant for restorative components Implant should be immobile at placement Adequate bone present between adjacent implants, between implants and adjacent teeth.
- #88 Bmp’s They have multiple effects, including the ability to differentiate osteoprogenitor cells into mineral-forming osteoblasts.