Dental implant materials

Tooth loss from disease has always been a feature of mankind’s existence. For centuries people have attempted to replace missing teeth using implantation.
This presentation includes an introduction to implant osseointegration mechanism, various implant biomaterials, selection critria, and recent advances in the field of implant biomaterials.

1. DENTAL IMPLANT MATERIALS Dr. Sonali Harjani First year postgraduate student

2. CONTENTS: Introduction Implant definition A peep into history Osseointegration Classification of implants Implant properties Attachment mechanisms Implant components Clinical success of implants

3. Risk factors in implant placement Implant materials -Metallic implants -Ceramic and ceramic-coated implants -Polymer implants -Carbon implants Selecting an implant material Biomechanical considerations Recent advances Summary

4. INTRODUCTION: Tooth loss from disease has always been a feature of mankind’s existence. For centuries people have attempted to replace missing teeth using implantation. But the origins of dental implants can be traced back to as early as the G reeks, E truscans and Egyptian civilizations. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

5. IMPLANT: REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Implant is any object or material, such as an alloplastic substance or other tissue, either partially or completely inserted or grafted, into the body for therapeutic, diagnostic, prosthetic, or experimental purposes . - GPT 8

6. A PEEP INTO HISTORY… The use of dental implants began as far back as the early centuries. The use of dental implant created from a shell was observed in Honduras in Central America, and is dated back to the 7 th century. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

7. Albucasis de Condue ( 936-1013) ox bone. The first documented placement of implants. Pierre Fauchard and John Hunter tooth transplantation. towards 18 th century The increased failure rates of transplants brought interest in implantation of artificial roots . REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

8. In 1809 Maggiolo G old roots fixed to pivot teeth by means of a spring. Harris in 1887 platinum post covered with lead Bonwell in 1895 gold or iridium tubes REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

9. Payne in 1898 silver capsule as foundation for porcelain crown In 1905, Scholl porcelain corrugated root implant In 1913 Greenfield hollow basket implant made from a meshwork of 24-gauge iridium- platinum wires soldered with 24- karat gold. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

10. The modern implants had their origin in the discovery by the hand of a Swedish orthopedic surgeon and research professor touted as ‘Father of modern dental implantology ’ Per - Ingvar Brånemark . In 1952, he discovered when pure titanium comes into direct contact with the living bone tissue, the two literally grow together to form a permanent biological adhesion. “ Osseointegration ” REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

11. O sseointegration The process in which living bone tissue forms to within 100 Angstrom units of the implant surface without any intervening fibrous connective tissue. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

12. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

13. CLASSIFICATION OF IMPLANTS: I. BASED ON IMPLANT DESIGN: A. ENDOSTEAL IMPLANT B. SUBPERIOSTEAL IMPLANT C. TRANSOSTEAL IMPLANT D. EPITHELIAL IMPLANT REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

14. II. DEPENDING ON IMPLANT MATERIAL : A. Metals and alloys ( Ti , Co-Cr-Mo alloys ) B. Non metallic ( polymers, ceramics) REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

15. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. III. Based on the biologic response : Gold Co-Cr Alloys Stainless steel Zirconium Tantalum CP Ti Ti Alloy (Ti-6Al-4V) Al 2 O 3 ZrO 2 HA TCP CaPO 4 Fluoroapatite Vitreous carbon Bioglass Polyethyene Polyamide PMMA Polytetra - fluoroethylene Polyurethane METALS: CERAMICS: POLYMERS: BIOTOLERANT: BIOINERT: BIOACTIVE:

16. ENDOSTEAL IMPLANTS: Most commonly used implants. Placed into the alveolar and/or basal bone of the mandible or maxilla and transects only one cortical plate. Shaped such as cylindrical cones or thin blades. Endosteal blade implants consist of thin plates embedded in the bone and are used for narrow spaces such as posterior edentulous areas. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

17. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

18. ENDOSTEAL IMPLANTS: Another example is the ramus frame implant, which is a horse-shoe shaped stainless steel device. The most popular endosteal implant is the root-form, designed to mimic the shape of tooth roots for directional load distribution as well as for proper positioning in the bone. It has the most documented success level of the endosteal implants. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

19. SUBPERIOSTEAL IMPLANT: A custom-cast frame which is placed directly beneath the periosteum overlying the bony cortex rests upon the bony ridge but does not penetrate it. T o restore partially dentate or completely edentulous jaws Indication: inadequate bone for endosseous implants. Limited use because of bone loss. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

20. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

21. TRANSOSTEAL IMPLANT C ombines the subperiosteal and endosteal components . Penetrates both cortical plates and passes through the full thickness of the alveolar bone. Use is restricted to anterior area of the mandible and provides support for tissue borne overdentures. Examples include staple bone implant , mandibular staple implant , transmandibular implant. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

22. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

23. EPITHELIAL IMPLANTS: These are inserted into the oral mucosa. Simple surgical technique which requires mucosa to be used as an attachment site for the metal inserts. Disadvantages include painful healing, requirements for continual wear No longer used. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

24. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

25. IMPLANT PROPERTIES These properties often include elastic moduli, tensile strength and ductility to determine optimal clinical applications . An implant with comparable elastic modulus to bone produces a more uniform stress distribution across the interface. Ductility potential for p ermanent deformation of abutments or fixtures in areas of high tensile stress. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

26. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Tensile , compressive and shear strength: prevents fractures and improve functional stability . Yield strength, fatigue strength : prevents brittle fracture under cyclic loading . Hardness and Toughness: Increase in hardness decreases the incidence of wear of implant material and increase in toughness prevents fracture of the implants

27. ATTACHMENT MECHANISMS Periodontal fibres - Most ideal form of attachment. Historically implant attachment through low differentiated fibrous tissue was widely accepted as a measure of successful implant implacement . Clinical studies indicate that this type of attachment eventually leads to an acute reaction, leading to implant failure. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

28. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

29. Osseointegration described by Branemark is now the primary attachment mechanism of commercial dental implants. This mode is described as direct adaptation of bone to implants without any other interstitial tissue and is similar to tooth ankylosis where no PDL exists: the strength of this contact increases over time. Osseointegration can also be achieved through the use of bioactive materials that stimulate the formation of bone. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

30. IMPLANT COMPONENTS Prosthesis: can be attached via screws, cement or precision attachment. Transmucosal abutment: connection between implant fixture and prosthesis . Fixture: implant component that engages the bone. May be threaded, grooved, perforated, plasma sprayed, or coated REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

31. Placement of implant done in various stages- REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

32. CLINICAL SUCCESS OF DENTAL IMPLANTS In 1979, Schnitman and Schulman proposed following requirements – Mobility of an implant must be less than 1 mm . No evidence of translucency . Bone loss should be less than one third the height of the implants . There should be absence of infection , damage to structures , or violation of body cavities . Success rate must be 75% or more after 5 years of functional service. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

33. In 1986, Albrektsson et al included the following conditions- Individual, unattached implant is immobile when tested clinically . Radiograph does not demonstrate periapical translucency. Vertical bone should be less than 0.2mm following implant’s first year of service . Absence of signs and symptoms such as pain , infections, neuropathies, paresthesia, or violation of mandibular canal . Success rate of 85% or more at end of 5 years; and 80% at end of 10 years. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

34. In 1989, Smith and Zarb modified Alberktsson’s criteria by stating: Patient’s and dentist’s satisfaction with the implant prosthesis should be the primary consideration and that aesthetic requirements should be met. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

35. Suggested criteria for implant success by Misch : REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Implant quality scale of 1, 2 or 3 with a survival rate better than 90% in 10 years. Prosthesis survival rate better than 90% in 10 years. Implants that are supporting a prosthesis.

36. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

37. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

38. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

39. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

40. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

41. RISK FACTORS THAT CAN MINIMIZE CLINICAL SURVIVAL Cigarette smoking . Osteopenia, Osteoporosis. Diabetes. Uncontrolled periodontal disease . Internal factors including bone height , bone density and attached mucosa . Severe mucosal lesions . Previous radiotherapy to the jaws . Bleeding disorders. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

42. IMPLANT MATERIALS: The most common ones are made from some form of metallic substance. Some implants are not coated; others are coated with ceramic, carbon, or a polymer. Implant materials are broadly: Metals and Ceramics. Other materials include: Polymers and carbon compounds. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

43. Stainless Steel REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Polymers Polymethyl methacralate Polytetra fluoroethylene Carbon compounds: Carbon SiC Vitreous Carbon DENTAL IMPLANT MATERIALS:

44. METALLIC IMPLANTS Metallic implants undergo several surface modifications to become suitable for implantation. Modifications are passivation , anodization, ion implantation and texturing. Titanium most commonly used implant material. Titanium – Gold standard in implant materials. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

45. TITANIUM: Discovered in 1789, by William Gregor. Atomic number – 22 Atomic weight – 47.9 Low specific gravity High heat resistance Melting point: 1668 degree celsius REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

46. High strength Ti oxidizes upon contact with room temperature air and normal tissue fluids: Oxidized surface condition minimizes bio-corrosion. Resistant to corrosion (due to titanium oxide): hence considered, Self-healing. Also, Ti can repassivate in vivo. Pure titanium forms several oxides: TiO , Rutile (TiO 2 ), Ilemenite (Ti 2 O 3 ) TiO 2 most stable. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

47. Ti and Titanium alloys most commonly used namely Ti-6Al-4V and Ti-6Al-4V extra low interstitial ( ELI: low levels of O 2 mixed in interstitial sites). Ti-6Al-4V most commonly used. Modulus of elasticity of Ti-6Al-4V is closer to that of bone. Ensures uniform distribution of stress along the bone-implant interface. ELI contains low levels of oxygen – improve the fracture toughness of the Ti alloy. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

48. The American Society for Testing and Materials(ASTM) committee F-4 on materials for surgical implants recognizes four grades of commercially pure Titanium and two Titanium alloys: CP titanium grade I (0.18% Oxygen) CP titanium grade II (0.25% Oxygen) CP titanium grade III (0.35% Oxygen) CP titanium grade IV (0.40% Oxygen ) Ti-6Al-4V alloy Ti-6Al-4V ( ELI alloy) REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

49. ADVANTAGES : High degree of biocompatibility High strength High corrosion resistance. DISADVANTAGES: High cost Difficult and dangerous to cast: A high vacuum or ultra- pure protective gas atmosphere is required. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

50. STAINLESS STEEL Surgical austenitic steel comprises of: 18% chromium and 8% nickel. Chromium provides corrosion resistance and nickel stabilizes the austenitic structure . Advantages: It has high strength and ductility, hence is resistant to brittle fracture. High Tensile strength Low cost and ease of fabrication REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

51. Disadvantages: Allergenic potential of Nickel. Susceptibility to crevice and pitting corrosion. Hence, care must be taken to use and retain the passivated surface condition. There may be chances of presence of a galvanic potential with the use of different materials such as Ti , Co, Zr , or C; which will decrease the corrosion resistance of steel. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

52. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Indications: Fabrication of Ramus blade, Ramus frame type of endosseous implants. Fabrication of mucosal insert systems.

53. COBALT-CHROMIUM MOLYBDENUM ALLOYS: Elemental composition of this alloy consists of- Cobalt- 63% Chromium- 30% Molybdenum- 5% Carbon, manganese and nickel- traces. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

54. COBALT: provides continuous phase of the alloy CHROMIUM: provides corrosion resistance through the oxide surface ( Cr 2 O 3 ). MOLYBDENUM : stabilizer; also provides strength and bulk corrosion resistance. CARBON: maintains ductility Secondary phases based on Co , Cr, Mo, Ni and C provide strength ( 4 times that of compact bone) and surface abrasion resistance. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

55. VITALLIUM was introduced by Venable in 1930’s and is part of Co-Cr-Mo alloy family. TICONIUM, Ni-Cr-Mo-Be alloy, was also used as a implant material. ADVANTAGES : Low cost and ease of fabrication DISADVANTAGES : Poor ductility Vitalium showed a chronic inflammation with no epithelial attachment and fibrous encapsulation accompanied by mobility. Ticonium showed less biocompatibility. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

56. I ndications: Larger implants like subperiosteal and transossteal implants because of their castability and lower cost . In cases where endosseous bone is not sufficient, Co-Cr alloy implants are used. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

57. CERAMIC AND CERAMIC COATED MATERIALS: Ceramics implants are of two types mainly: BIO-INERT: aluminium oxide BIO-ACTIVE: hydroxyapatite. GENERAL PROPERTIES OF CERAMICS: High compressive strength upto 500 MPa . Less resistance to shear and tensile stress High modulus of elasticity Brittle REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

58. Ceramic implants can withstand only relatively low tensile stresses. Tolerate high levels of compressive stresses. Al 2 O 3 used as a gold standard for ceramic implants because of its inertness and no evidence of immune reaction in vivo. ZrO 2 also demonstrated high degree of inertness. These ceramic materials are not bio-active. Have high strength , stiffness, and hardness and function well as subperiosteal or transosteal implants REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

59. Use of calcium phosphates as coating materials for metallic implants promotes bone to implant integration. The more HA coating the more resistant it is to clinical dissolution. A min. of 50% crystalline HA is considered an optimal concentration in coating of implants. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

60. Dissolution of the ceramic coating occurs at a higher rate with a more amorphous HA structure. Advantage of ceramic coating: they stimulate the adaptation of bone. Greater bone to implant integration with the HA coated implants. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

61. Another form of bioactive ceramics are bioglasses . Known to form a carbonated hydroxyapatite layer. Formation of layer is initiated by migration of calcium , phosphate, silica, and sodium ions towards tissue . Silica gel layer is formed. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

62. Silicon depletion initiates migration of calcium and phosphate ions . Calcium-phosphorous layer is formed that stimulates osteoblasts to proliferate, stimulating the formation of bone. Bioglasses are very brittle , which makes them unsuitable for use as stress bearing implant materials. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

63. ADVANTAGES : Excellent biocompatibility Minimal thermal and electrical conductivity Color is white, cream or slightly grey: beneficial for anterior root-form devices. Chemical composition is similar to constituents of normal biological tissues. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

64. DISADVANTAGES : Low mechanical, tensile and shear strength under fatigue loading . Low ductility, inherent brittleness. Variations in chemical and structural characteristics Low attachment strengths for some coatings with substrate interfaces. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

65. POLYMERS Polymeric implants -First used in 1930 , s. During 1940s methyl methacrylate was used for temporary acrylic implants to preserve dissected space to receive a Co-Cr implant later REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

66. DISADVANTAGES: Low mechanical strength hence susceptible to mechanical fracture Physical properties of polymers are greatly influenced by changes in temperature, environment and composition. Their sterilization can be accomplished only by gamma irradiation or exposure to ethylene oxide gas. Contamination of these polymers because of electrostatic charges that attract dust and other impurities from the environment REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

67. IMZ IMPLANT: Intra-Mobile Cylinder implant system. The use of polymers for osseointegrated implants is now confined to its components. The IMZ implants are either plasma sprayed or HA-coated and incorporate a polyoxymethylene ( POM) intra mobile element(IME) which acts as a shock absorber. IME is placed between the prosthesis and the implant body to initiate mobility, stress relief and shock absorption capability to mimic that of the natural tooth. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

68. CARBON AND ITS COMPOUNDS: Carbon and its compounds(C and SiC ) were introduced in the 1960s for use in implantology . VITREOUS CARBON, which elicits a very minimal response from the host tissues, is one of the most biocompatible material REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

69. ADVANTAGES: Carbon is inert under physiological conditions. Has a modulus of elasticity equivalent to that of dentin and bone. Thus it deforms at the same rate as these tissues enabling adequate stress distribution. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

70. DISADVANTAGES: Because of its brittleness, carbon is susceptible to fracture under tensile stress, which is usually generated as a component of flexural stress. It also has a relatively low compressive strength. Thus a large surface area and geometry are required to resist fracture. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

71. SELECTING AN IMPLANT MATERIAL Important consideration is the strength of implant material and type of bone in which implant is placed. For high load zone like in posterior areas, high strength material such as CP grade IV titanium or titanium alloys are used. Anterior implants designated for use in narrow spaces have smaller diameters in range of 3.25mm. Single implants placed in posterior areas have large diameters up to 5.0 mm REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

72. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

73. D1 and D2 bone → initial stability / better osseointegration D3 and D4 → poor prognosis D4 bone - most at risk Jaffin and Berman (1991) – 44% failure in type IV bone

74. Gottlander and Albrektsson examined bone to implant contact area both at 6 weeks and 12 months for HA and CPTi coated implants. They concluded that bone – implant contact at 6 weeks was 65% for HA and 59% for Ti . However at 12 months Ti exhibited 75% contact area versus 53% for HA REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

75. Some studies showed survival rate of HA-coated implants is initially higher than that that for titanium plasma sprayed implants , but decreased after 4 yrs. Due to the adherence of microorganisms to HA surface. A study revealed colonisation of coccoid and rod shaped bacteria on HA implants. Roughened surface of HA implants also contribute to plaque growth once coating is exposed. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

76. Numerous osteocytes were found along periphery of HA implants making it a better option for poor bone quality areas such as maxilla. Branemark type titanium implants were evaluated in type IV bone and a survival rate of 63% was found for mandibular implants and 56% for maxillary implants. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

77. BIOMECHANICAL CONSIDERATIONS: The attachment of bone to implants serves as the basis for the biomechanics analysis performed for dental implants. ATTACHMENT MECHANISMS: Fibro osseous integration (Weiss 1986) Bio osseous integration ( Putter 1985) Osseointegration ( Branemark 1969) REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

78. Osseointegration - Is defined as the close approximation of bone to an implant material . To achieve osseointegration bone must be viable and space between bone and implant must be less than 10 nm, and should contain no fibrous tissue. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

79. SEM of Implantation site, at bone implant interface, 28 days after osseointegration

80. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications.

81. Principal factors governing osseointegration : REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. SHAPE OF IMPLANT SHAPE OF IMPLANT THREADS SURFACE MODIFICATIONS

82. 1) SHAPE OF IMPLANT: REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Cylindrical/ press-fit implants cause bone resorption There is lack of bone steady state: micro-movements.

83. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Albrektsson in 1993, studied continuing bone saucerization of 1mm for the first year of placement of cylindrical implants, 0.5mm annually and thereafter increasing rate of resorption upto 5 year follow-up. This suggested that osseointegration is poor or does not take place in case of cylindrical implants.

84. 2) SHAPE OF IMPLANT THREADS REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. These are documented for long term clinical function. Alteration in the design, size, and pitch of the threads influences the long-term osseointegration .

85. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. THREAD PITCH: The more the number of threads, the greater the functional surface area. Threads improve the primary implant stability and avoid micro-movement of the implants till osseointegration is achieved.

86. 3) SURFACE MODIFICATIONS REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. They can be via: Additive methods: T itanium plasma spraying, Hydroxyapatite coating Subtractive methods: Sand blasting, Acid etching.

87. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Titanium plasma spraying: -Involves plasma spraying a powder form of molten droplets at high temperatures - at temperatures in the order of 15,000 degree Celsius, an argon plasma provides a very high velocity of 600 m/sec and partially molten particles of titanium are projected onto a metal or alloy substrate.

88. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Hydroxyapatite coating: -HA coated implant bioactive surface structure has more rapid osseous healing compared to smooth surfaced implant. -This increases the initial stability. - Indicated in fresh extraction, and newly grafted sites. -Coatings are applied by plasma spraying small sized particles of crystalline HA ceramic powders.

89. REFERENCE: Kenneth J. Anusavice, Phillip’s Science of Dental Materials, 11th edition, Saunders publications. Sand blasting and acid etching : -Sand blasting increases the surface roughness, whereas acid etching helps in cleaning. -Sand blasting is done with 200-400 microns coarse corundum particles and acid etching with 1% HF acid and 30% NO 2 after sand blasting increases osseointegration .

90. RECENT ADVANCES: In an attempt to replace a missing tooth many materials have been tried as an implant. With all the advancements and developments in science and technology, the materials available for dental implants have also improved. In the present era, due to the extensive research work and advancements in the field of biomaterials available for dental implants newer materials and techniques have come into being.

91. I ncorporating biologically active drugs on the dental implant surface:   It is studied that bisphosphonates incorporated on to titanium implants increased bone density locally in the peri -implant region with the effect of the anti- resorptive drug limited to the vicinity of the implant . Another such biologically active drug includes statins. Simvastatin-loaded porous implant surfaces were found to promote accelerated osteogenic differentiation of preosteoblasts , which have the potential to improve the nature of osseointegration . Prasad D K, Mehra D, Prasad D A. Recent advances, current concepts and future trends in oral implantology . Indian J Oral Sci 2014;5:55-62

92. Antibacterial coatings: Antibacterial coatings such as Gentamycin along with the layer of HA or tetracycline treatment has been regarded as a practical and effective chemical modality for decontamination and detoxification of contaminated implant surfaces. Further , it inhibits collagenase activity, increases cell proliferation as well as attachment and bone healing. Prasad D K, Mehra D, Prasad D A. Recent advances, current concepts and future trends in oral implantology . Indian J Oral Sci 2014;5:55-62

93. Titanium-zirconium alloy ( Straumann Roxolid ) Titanium zirconium alloys with 13%-17% zirconium have better mechanical attributes, such as increased elongation and the fatigue strength, than pure titanium. Growth of osteoblasts, that are essential for osseointegration is not prevented by Titanium and Zirconium. Straumann developed Roxolid that is 50% stronger than pure titanium. Saini M, Singh Y, Arora P, Arora V, Jain K. Implant biomaterials: A comprehensive review.  World J Clin Cases  2015; 3(1): 52-57

94. Titanium Porous Oxides ( TiUnite ) Oral Implants: It was studied TPO surface possesses a considerable osteoconductive potential promoting a high level of implant osseointegration in type IV bone in the posterior maxilla. the local bone formation and osseointegration are found to be increased. Huang YB, Xiropaidis AV, Sorensen RG, Albandar JM, Hall J, Wikesjo UM. Bone Formation Of Titanium Porous Oxides ( TiUnite ) Oral Implants In Type IV Bone. Clinical Oral Implant Res 2005, Vol 16 Issue 1 ; 105-111

95. Incorporation of Fluorides: By using hydrogen fluoride at low concentrations it is possible to manipulate the titanium dioxide without changing the surface micro texture significantly. Fluoride is suggested to have an action on osteoprogenitor cells and undifferentiated osteoblasts. This induces the differentiation of these precursor cells into osteoblasts and subsequently new bone formation. In a clinical situations, this gives a faster bone healing after implantation and more supporting bone surrounding the implant. Ellingsen , J. E., Thomsen, P. and Lyngstadaas , S. P. (2006), Advances in dental implant materials and tissue regeneration. Periodontology 2000, 41: 136–156.

96. SUMMARY: Implant dentistry enables the restoration of nearly every clinical situation ranging from partially to totally edentulous patients with greater success and predictability. When the mechanisms that ensure implant bio acceptance and structural stabilization are fully understood, implant failures will become a rare occurrence. Modern dentistry is beginning to understand, realize, and utilize the benefits of biotechnology in health care. Study of material sciences along with the biomechanical sciences provides optimization of design and material concepts for surgical implants; thus improving the treatment prognosis.

97. REFERENCES: Textbook on contemporary implant prosthesis by Carl E. Misch . Second edition. Textbook on Phillip’s Science of dental materials by Kenneth J. Anusavice . Eleventh edition. Textbook on Dental Implant Prosthesis by Carl E. Misch . First edition. Textbook on Craig’s Restorative dental materials by Ronald L. Sakaguchi and John M. Powers. Thirteenth edition.

98. THANK YOU!! THANK YOU!!