dental implants

focuses on the history and the various materials used in dental implants

1. DEPARTMENT OF ORAL & MAXILLOFACIAL SURGERY DENTAL IMPLANTS 24/09/2019 Presented By: Dr. Samarth Johari

2. CONTENTS Introduction History Factors affecting osseointegration Rationale of dental implants Classification of dental implants Parts of dental implants Surface characteristics of dental implants Methods to alter surface texture Current implant design trends Implant surface chemical composition Pretreatment evaluation Diagnostic work up The radiographic stent Bone evaluation Implant with natural teeth References

3. INTRODUCTION Goal of modern dentistry : to restore normal contour, function, comfort, esthetics, speech and health of a patient Since, partial and removable prosthesis may not bring satisfactory results Dental implants designed to provide a foundation for replacement of teeth that look, feel, and function like natural teeth

4. What is an implant?? Any object or material, such as an alloplastic substance or other tissue , which is partially or completely inserted or grafted into body for therapeutic , diagnostic, prosthetic or experimental purposes

5. What is a dental implant?? According to Charles M Weiss: Can be defined as a substance that is placed into the jaw to support a crown or fixed or removable denture According to Edward J Fredrickson: A prosthetic device or alloplastic material implanted into oral tissues beneath the mucosal or periosteal tissues and/or within the bone to provide retention and support for fixed or removable prosthesis

6. HISTORY According to Archeological findings: the ancient Egyptian and South American civilizations experimented with re-implanting lost teeth with hand-shaped ivory or wood substitutes In the 18th century lost teeth were sometimes replaced with extracted teeth of other human donors The implantation process was probably somewhat crude and the success rates extremely low due to the strong immune reaction of the receiving individual

7. Modern dental implant history dates back to World War II Dr. Norman Goldberg used metals for dental restorations Later on in 1948 , along with Dr. Aaron Greshkoff , produced 1 st successful sub-periosteal implant In 1957 , Per-Ingvar Branemark gave the phenomenon of ‘osseointegration’

8. Phenomenon of Osseointegration: I t states that the bone could grow in proximity with the titanium (Ti) & that it could be adhered to the metal without being rejected

9. 1 st Ti dental implant was placed by Branemark in 1965 which was used as a foundation for fixation of prosthetic teeth several months later In 1982, use of Ti dental implants was approved by US Food & Drug Administration In 1992, modern ceramics were developed after which the dental implant companies incorporated ceramic surface treatments & ceramic like elements to implants to enhance osseointegrtion

10. FACTORS AFFECTING OSSEOINTEGRATION

11. Biomaterials: Polymers Metals Ceramics Combinations

12. Implant Design: Length Diameter Geometry Threads

13. Biomechanical Factors: Primary anchorage of implants is by mechanical interlocking 32% implant failure rate in case of inadequate initial implant stability Biomechanical stability depends on implant material, design, quality & quantity of bone

14. Surface Characteristics: Biological response mediated by surface of implant Initial stage is adsorption of specific proteins, lipids, sugar & ions that activates cell mechanism to induce either acceptance or rejection of implant According to literature, osteoblastic cells adhere more rapidly to rough surfaces as compared to smooth surfaces

15. Surface Characteristics: Biological response mediated by surface of implant Initial stage is adsorption of specific proteins, lipids, sugar & ions that activates cell mechanism to induce either acceptance or rejection of implant According to literature, osteoblastic cells adhere more rapidly to rough surfaces as compared to smooth surfaces

16. Medical Status of Patient: Success rate in healthy pt. is 90-95% Systemic risk factors can increase risk of treatment failure or complications Conditions that increase risk of failure- Smoking b) Endocrine disease c) Osteoporosis d) Microbial & immune inflammatory factors e) Chemotherapy f ) Cardiovascular disease g) M yocardial infarction h ) Cerebrovascular accidents i ) Bleeding disorders

17. Bone Quality: Poor bone quality/quantity leads to poor anchorage & stability of implant The more the bone around the implant surface the better is the implant stability

18. RATIONALE OF DENTAL IMPLANTS Treatment options available: Removable Partial Denture Fixed Partial Denture Implant

19. Why implants are better options than other treatment modalities????

20. CLASSIFICATION OF DENTAL IMPLANTS Dental implants may be classified under four categories : Depending on the placement within the tissues Depending on the materials used Depending on their reaction with bone Depending on the treatment options

21. Depending on the placement within the tissues: Depending on the placement within the tissues, implants can be classified into – An implant which is placed into the alveolar bone and/ or basal bone of the mandible or maxilla Transects only one corticle plate Most commonly used It consists of thin plates in the form of blade embedded into the bone Designed to mimic the shape of the tooth For directional load distribution Horse shoe shaped stainless steel device Inserted from one retromolar pad to other

22. Placed directly beneath the periosteum overlying the bony cortex Do not penetrate into the jawbone. Consists of non-Osseo integrated framework that rests on the surface of the jaw or beneath the m ucoperiosteum . Can be bilateral or unilateral

23. Transosteal implants Other names- staple bone i mplant Mandibular staple implant Transmandibular implant Combines the subperiosteal and endosteal components Penetrates both cortical plates very similar to a nut and bolt arrangement Used in mandibles only penetrate the entire jaw to emerge opposite the entry site, usually at the bottom of the chin.

24. Depending on the materials used : Based on the materials used, the implants can be classified into – Metallic implants – Titanium, Titanium alloy, Cobalt Chromium Molybdenum alloy Non- metallic implants – Ceramics, Carbon etc .

25. Depending On Their Reaction With Bone : Based on the ability of the implant to stimulate bone formation, implants can be classified into – Bioactive implants – Hydroxyapatite Bio-inert implants – metals

26. Depending on the treatment options : FP- 1: Fixed prosthesis; replaces only the crown; looks like a natural tooth FP- 2: Fixed prosthesis; replaces the crown and a portion of the root; crown contour appears normal in the occlusal half but is elongated or hypercontoured in the gingival half

27. FP- 3: Fixed prosthesis; replaces missing crowns and gingival color and portion of the edentulous site; prosthesis most often uses denture teeth and acrylic gingival, but may be made of porcelain, or metal RP-4 : Removable prosthesis; overdenture supported completely by implant RP-5 : Removable prosthesis; overdenture supported by both soft tissue and implant.

28. Described by Dr CHARLES WIESS Complete encapsulation of implant with soft tissue Soft tissue interface could resemble highly vascular periodontal fibers of natural dentition Described by BRANEMARK Direct contact between bone & surface of loaded implant Bio active materials that stimulate formation of bone are used OTHER CLASSIFICATIONS Based on attachment mechanism:

29. Based on macroscopic body design of implant:

30. In the form of cylinder Depends on coating or surface conditioning to provide microscopic retension & bonding to bone pushed or tapped into prepared bone site Straight, tapered or conical Threaded dental implants The surface is threaded, to increase surface area of implant This results in distribution of forces over greater peri-implant bone volume Perforated dental implants are made of inert micro porous membrane material (mixture of cellulose acetate) in intimate contact with & supported by layer of perforated metallic sheet material (pure titanium) Cylindrical dental implants

31. Plateau dental implant Plateau shaped implant with sloping shoulder Solid dental implant They are of circular cross section without vent or hollow in the body Vented dental implant It is hydroxyapetite coated cylinder with patented vertical groove connecting to apical vents designed to facilitate seating and allow bone in growth to prevent rotation Hollow dental implant Hollow design in apical portion Systematically arranged perforations along sides of implant Increased anchoring surface

32. Based on surface of implant:

33. Smooth surface implant Has very smooth surface Surface is smoothened to prevent microbial plaque retention Machined surface implant Surface of implant is machined for better anchorage of implant to bone Textured surface implant Have increased rough surface area to which bone can bond Coated surface implant Implant is covered with porous coating such as titanium & hydroxyapatite

34. d) According to loading : Immediate(<2weeks) Early(2weeks -2mts) Delayed (>3mts ) e) According to method of placement : Tapping system Threading system

35. PARTS OF DENTAL IMPLANTS

36. Implant Body or Fixture: the component that is placed within the bone during first stage of surgery Implant Body or Fixture Materials Used: Titanium & titanium oxide Abutment : Is the part of implant, which resembles a prepared tooth, and is designed to be screwed into the implant body via Abutment screw It is the primary component, which provides retention to the prosthesis Abutment Materials Used: Titanium Crown: replicate the original teeth to provide a biting surface and aesthetic appearance Crown Material Used: Porcelains (metal supported or metal free) or metal (normally gold)

37. Cover Screws: During the healing phase, this screw is normally placed in the superior surface of the body Functions -Facilitates the suturing of soft tissue over the edge of the implant Healing Abutment: dome-shaped screws. Length ranges from 2-10mm. Project through the soft tissue into the oral cavity Function -prevent overgrowth of tissues around the implant during healing phase

38. Analogue or Implant Replica: Analogues are used by laboratory technicians to replicate implants and their position in a patient’s mouth. The analogue , screwed onto the impression coping, is set into the plaster model during casting Impression posts/coping: Is a small stem that facilitates the transfer of the intraoral location (of the implant or the abutment) to a similar position on the cast. They are screwed into implant body during impression making

39. SURFACE CHARACTERISTICS OF DENTAL IMPLANTS Roughness parameters: 0.04 –0.4 μ m - smooth 0.5 – 1.0 μ m – minimally rough 1.0 –2.0 μ m – moderately rough 2.0 μ m – rough Wennerberg (1996) – Moderately rough implants developed the best bone fixation

40. In vivo studies: Smooth surface < 0.2 μ m will – dislodged fibrin clot no bone cell adhesion clinical failure Moderately rough surface- more bone in contact with implant better osseointegration

41. METHODS TO ALTER SURFACE TEXTURE Additive surface treatment: Titanium plasma spraying & hydroxyapetite coating Abrasive surface treatment: Grit blasting b) Acid etching c) Grit blasting with acid etching Modified surface treatment: a) Oxidized surface treatment b) Laser treatment c) Ion implantation

42. Additive surface treatment: Titanium Plasma Sprayed Coating (TPS)- the first rough titanium surface introduced by this procedure Coated with titanium powder particles in the form of titanium hydride ADVANTAGES of TPS & HA COATING Steinemann (1988 ) Tetsch (1991)- Titanium Plasma Sprayed coating provide 6-10 times increase surface area. HA coating can lower the corrosion rate of the same substrate alloys . HA coatings has been credited with enabling to obtain improved bone to implant attachment compared with machined surface

43. Ceramic And Ceramic Coated Implants- Ceramic materials are used to coat metallic implants to produce an ionic ceramic surface, which is thermodynamically stable and hydrophilic, thereby producing a high strength attachment to bone and surrounding These ceramic can either be plasma sprayed implant to produce bio-active surface Aluminum oxide (Al2O3) is used as the gold standard for ceramic implants because of its inertness with no evidence of ion release or immune reaction in vivo Zirconia (ZrO2) has also demonstrated high degree of inertness

44. Abrasive surface treatment: Blasting- Blasting with particles of various diameters is one of the frequently used method of surface alteration. In this approach, the implant surface is bombarded with particles of aluminum oxide (Al2O3) or titanium oxide (TiO2), and by abrasion, a rough surface is produced with irregular pits and depressions Roughness depends on particle size, time of blasting, pressure, and distance from the source of particles to the implant surface SAND BLASTED IMPLANT

45. Sand Blasting & Acid Etching- Wennerberg et al 1996 - superior bone fixation and bone adaptation Lima YG et al (2000), Orsini Z et al (2000 )- Acid etching with NaOH , Aq. Nitric acid, hydrofluoric acid – better cell attachment Acid etching with 1% HF and 30% NO3 after sand blasting - increase in osseointegration by removal of aluminium particles (cleaning) The objective Sand blasting – surface roughness Acid etching – cleaning

46. Modified Surface Treatment: Porous Surface- Porous sintered surfaces are produced when spherical powders of metallic or ceramic material becomes a coherent mass with the metallic core of the implant body. Lack of sharp edges is what distinguishes these from rough surfaces. Porous surfaces are characterized by pore size, pore shape, pore volume, and pore depth, which are affected by the size of spherical particles and the temperature and pressure conditions of the sintering chamber Surface of a porous titanium implant

47. Advantages of porous implant surface- secure, 3-D interlocking interface with bone predictable and minimal crestal bone remodeling Greater surgical options with shorter implant lengths Shorter initial healing times Porous coating implants provide the space, volume for migration and attachment, thus support contact osteogenesis .

48. Laser Induced Surface Roughening- Eximer laser – “Used to create roughness ” Advantage- Regularly oriented surface roughness configuration compared to TPS coating and sandblasting SEM x 300 SEM x 70

49. CURRENT IMPLANT DESIGN TRENDS Finite element analysis: Becoming a common method to study jaw bone & implant properties & bone-implant interface Helps to understand how to improve implant design in order to function within physiological acceptable limits Consists of computerized 3-D model to carry out the study

50. Computer aided design & computer aided manufacturing technology: The main advantages of using CAD/CAM technology- provides accuracy & less time consuming for manufacturing parts Micro casting: Uses metal melt that is casted into micro structured mold Enables manufacture of small structures & complex geometrical details in micrometer range Advantages- a) low cost b) scalability from single items to large numbers of identical items

51. Electron Microscopy: Allows accurate measurements of lattice parameters as well as analysis of microstructures & grain sizes of surface layer Nanotechnology based implants: Consists of surface roughness modification on nanoscale level to promote protein adsorption & cell adhesion

52. IMPLANT SURFACE CHEMICAL COMPOSITION Titanium - very reactive metal that oxidizes within nanoseconds when exposed to air . Passive oxide layer of the titanium -very resistant to corrosion. All titanium oxides have dielectric constants, which are higher than for most other oxides - tendency to adsorb biomolecules

53. PRETREATMENT EVALUATION Chief complaint Medical history: – MEDICATIONS,ALLERGIES Social history , family history Dental history A thorough clinical assessment should be undertaken for every patient before undergoing therapy.

54. KEY POINTS IN HISTORY: Gender ..no influence on the outcome. Women after menopause more prone to develop osteoporotic conditions. ( Lekholm et al. 1994, Friberg et al. 1997, Sennerby & Rasmusson 2001 ) Age..no influence.. In osseointegration. implants become bone anchored both in young ( Thilander et al. 1994 ) & in elderly individuals ( Kondell et al. 1988, Jemt 1993) Still…elderly patients more susceptible to infections… slow healing . ( Sermerby & Rasmusson 2001)

55. Growing individuals… rather react like ankylotic teeth... infra-occlusion (Oilman 1994) Not the chronological age but dental/skeletal maturation considered in adolescents ( Thilander et al. 1994 ) In young adults requiring tooth replacement, implant placement should be postponed after the age of 25 due to the prolonged changes in anterior face height & posterior rotation of the mandible ( Jemt T 2007)

56. DIAGNOSTIC WORK UP Photographs Study models Radiographs Diagnostic waxup

57. Radiographic examination: Phase I - pre surgical implant imaging Phase II - surgical and intra operative implant imaging Phase III - post prosthetic implant imaging

58. Imaging modalities: Periapical radiography Panoramic radiography Occlusal radiography Cephalometric radiography Tomography Computed tomography Interactive computed tomography Magnetic resonance imaging

59. Interactive computed tomography: Interactive CT in conjunction with a surgical guide stent, can help guide dental implant placement into the ideal position with respect to function and esthetics.

60. Simplant : There are 3 basic views available on simplant TM screen The Panoramic view is similar to a normal two dimensional panoramic view

61. The axial view offers a perspective from a coronal/apical direction There is a cross-sectional view that allows a mesial/distal perspective of the arch.

62. All three of these views correlate to each other When a marker is moved on one view it corresponds to the other two views. The final perspective is a 3 dimensional view The 3 dimensional view allows the clinician to check for parallelism of implants

63. THE RADIOGRAPHIC STENT Radiographic stent - (can double as surgical stent) Acrylic stent with lead beads or ball -bearings (5mm) placed in proposed fixture locations, allows more accurate radiographic interpretation

64. E d ent u lo us jaw Clear Acrylic Stent RPD Impression

65. Place Metal Tubes in the Stent Make a Radiograph Stent for surgery

66. BONE EVALUATION Available bone: is the amount of bone in the edentulous area considered for implantation it is measured in : width height length angulation crown : implant

67. Maxillary canine eminance - - greater height of alveloar bone than max ant or post region Mand canine & premolar reduced height than anterior anterior loop of mandibular canal

68. Available bone angulation : Ideally it is aligned with the forces of occlusion & is parallel to the long axis of prosthodontic restoration angulation of force b / w the body & the abutment of an implant is correlated with the width of the bone. wider ridge -30degree angulation. The narrow width ridge- requires a narrower design root form implant which cause greater crestal stress – so the acceptable angulation is 20

69. IMPLANT WITH NATURAL TEETH 0.5mm for PDL Space on either sides 2 - 2.5mm space: soft tissue Edentulous space dimensions :

70. Inter-arch space: Sufficient inter-arch space is necessary Rule: For fixed implant-supported prosthesis: 7 mm - in the posterior region 8-10 mm - in the anterior areas An implant-retained removable prosthesis requires at least 12 mm.

71. REFERENCES Contemporary implant dentistry by Carl E. Misch Yeshwante B. et al, Dental Implants- Classification, Success and Failure –An Overview, IOSR-JDMS, 2015; 14:5:2:01-08 Hong DG, Oh JH; recent advances in dental implants; maxillofacial plastic & reconstructive surgery; 2017; 39:33 Gaviria et al; current trends in dental implants; Korean Assoc Oral Maxillofac Surg 2014;40:50-60 Abraham CM; a brief historical perspective on dental implants, their surface coatings & treatments; the open dentistry journal; 2014,8,50-55 Rajput R et al; a brief chronological review of dental implant history; international dental journal of students research; 2016; 4(3):105-107