Occlusion in dental Implantology .pptx

Complete concepts about Occlusion in implant dentistry

1. IMPLANT OCCLUSION

2. CONTENT: INTRODUCTION DEFINITIONS KEY DIFFERENCE B/W IMPLANT & NATURAL TEETH TYPES OF OCCLUSION SCHEME AND PRINCIPLES OF OCCLUSION IMPLANT OCCLUSION BASED ON VARIOUS SITUATIONS OCCLUSAL OVERLOADING & ITS CAUSES CONCLUSION REFERENCES

3. INTRODUCTION: Implant treatment has become the treatment of choice and the most desirable treatment option for replacing missing teeth in partially as well as completely edentulous patient . Dental implants have different biological and biomechanical characteristics compared to natural tooth . One of the most important criteria for implant success is implant occlusion and that is why implantology should be prosthetically driven.

4. DEFINITIONS: OCCLUSION : The static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues. -GPT 9 IDEAL OCCLUSION : Occlusion compatible with stomatognathic system providing efficient mastication & good esthetics without creating abnormalities. -HOBO -1978

5. KEY DIFFERENCE B/W IMPLANT & NATURAL TEETH:

6. Basic concepts of ideal occlusion: Centric relation Anterior guidance must be in harmony with the border movements. Disclusion of all the posterior teeth in protrusive movements. Disclusion of all the posterior teeth on the balancing side. Non interference of all posterior teeth on the working side and the border movements of the condyles. Yogeshwari , Gururaj Rao . Implant protected occlusion. IOSR Journal of dental and medical sciences- 2013

7. TYPES OF OCCLUSION: BALANCED OCCLUSION GROUP FUNCTION OCCLUSION CANINE GUIDED OCCLUSION MUTUALLY PROTECTED OCCLUSION

8. BILATERALLY BALANCED OCCLUSION According to GPT 9: This occlusal scheme helps to distribute lateral forces through out all teeth during mastication. It has both cross tooth and cross arch balance. It can be used for over dentures supported by osseointegrated implants. 9

9. GROUP FUNCTION OCCLUSAL SCHEME: It is defined as multiple contact relationships between maxillary and mandibular teeth in lateral movements on working side, where by simultaneous contact of several teeth acts as a group to distribute occlusal forces . SHCHUYLER (1929) introduced the fundamentals of group function occlusion. This type of occlusion occurs where all facial ridges of working side teeth do not contact. In this type, excessive contact occurs between all opposing posterior teeth on the laterotrusive (working) side only. On mediotrusive (nonworking) side, no contact occurs until the mandible has reached the centric relation. 10 Sidana V, Pasricha N, Makkar M, Bhasin S. Group function occlusion. Indian J Oral Sci 2012;3:124-8

10. Mutually protected occlusion According to GPT-9, it is defined as an occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in maximum intercuspation and the anterior teeth disengage the posterior-teeth in all mandibular excursive movements . This occlusal scheme was advocated by Stuart and Stallard (1960), based on work by D’Amico . The features of MPO are In maximum intercuspation , posterior teeth protect anterior teeth. In protrusive movement anterior teeth protects the posterior teeth and during lateral movements canine protects the posterior teeth. No contacts of posterior teeth in lateral or protrusive movements. 11 Pasricha N, Sidana V, Bhasin S, Makkar M. Canine protected occlusion. Indian J Oral Sci 2012;3:13-8.

11. CANINE PROTECTED OCCLUSION: D’amico performed a study on canines in animals and human beings and advocated a canine guided occlusion . This theory suggests that the only tooth contact in all positions of the mandible except CR should be between maxillary cuspids and mandibular cuspids . Functional occlusion J. R. Clark. JO 2001;28:76-81 .

12. SCHEME & PRINCIPLES OF OCCLUSION: For implant occlusion, a specifically designed occlusal scheme named IMPLANT PROTECTIVE OCCLUSION (IPO) was designed by Misch and Bidez along with 10 principles.

13. Implant protected occlusion OBJECTIVES OF IPO: To reduce noxious occlusal load and to establish a consistent occlusal philosophy , Implant-protected occlusion concept addresses several conditions to minimize overload on bone-implant interfaces and implant prostheses Maintains implant load within the physiological limit

14. IPO was previously known as medial positioned- lingualized occlusion . This occlusal concept refers to an occlusal plane that is often unique and specifically designed for the restoration of endosteal implant . The primary goal of IPO is to maintain the occlusal load that has to be transferred to the implant body within the physiologic limits of each patient.

15. Factors influencing implant protected occlusion Timing of occlusal contacts No premature occlusal contacts or interferences Influence of surface area Mutually protected articulation Implant body angle to occlusal load Cusp angle of crown ( cuspal inclination ) Cantilever or offset distance Crown height Occlusal contact position Implant crown contour

16. TIMING OF OCCLUSAL CONTACTS Implant has no PDL so concerns arise about potential of nonmobile implant to bear total load of the prostheses when joined to the mobile natural tooth Sudden initial tooth movement is 8-28 μ in vertical direction under 3-5 lb load Secondary tooth movement depends on property of sorrounding bone. Implant has no initial sudden movement & may move 3-5 μ after bone causes it to move.

17. 2.NO PREMATURE OCCLUSAL CONTACT The occlusal adjustment of implants & teeth should compensate for the primary tooth movt . The light occlusal contacts evaluates primary tooth movt . The heavy occlusal contact evaluates the 2 nd tooth movt . Thin articulating paper (less than 25 μ thickness) is then used for the initial implant occlusal adjustment in centric relation occlusion under a light tapping force. The implant prosthesis should barely contact, and the adjacent teeth should exhibit greater initial contacts. Only axial occlusal contacts should be present on the implant crown.

18. 3. INFLUENCE OF SURFACE AREA An important part of IPO is the adequate surface area to sustain load transmission to the prosthesis. Wider diameter root form implants have a greater area of contact at the crest than narrow implants which reduces the mechanical stress at the crest. When narrow diameter implants are used in regions that receive greater loads, additional splinted implants are indicated to compensate for the design .

19. Implants should be placed in a staggered manner & not in a straight line to increase the surface area.

20. Also,the implant surface area can be increased with the help of surface coated implants, TITANIUM PLASMA SPRAY (TPS) COATED IMPLANTS PLASMA COATING HYDROXYAPATITE COATING

21. 4. MUTUALLY PROTECTED ARTICULATION When the natural canines are present, during excursions it allows the teeth to distribute horizontal load and also the posterior tooth to disocclude . This concept is known as canine guidance or mutually protected articulation.

22. The anterior guidance of implant prosthesis with anterior implant should be shallow . This is because, the steeper the incisal guidance the greater the force on the anterior implants . Weinberg et al have reported a study stating, every 10- degree change in the angle of disclusion , there is a 30 % difference in the load. Weinberg LA, Kruger G, A comparison of implant prostheses loading for clinical variables, Int J Prosthodont,8 , 1995, 421-433.

23. 5. CROWN CUSP ANGLE: The angle of force to the implant body may be influenced by cusp inclination Natural dentition has steep cuspal inclination whereas in denture teeth, the cuspal inclination given is 30 %. Cusp inclination has been found to produce a high level of torque. For every 10° increase in cusp inclination, there is an approximately 30% increase in torque .

24. The occlusal contact over an implant crown should be ideally on a flat surface perpendicular to the implant body. This position is accomplished by increasing the width of the central groove to 2 to 3 mm in posterior implant crowns. The opposing cusp is recontoured to occlude the central fossa directly over the implant body. 25

25. Natural teeth 30ºcusp angles Cusp angles modify the direction of force to the implant resulting in angled load to crestal bone Occlusal contact on an implant crown ideally is a flat surface created by increasing the width of central groove to 2-3mm and recontour opposing cusp

26. 6. IMPLANT BODY ANGLE TO OCCLUSAL LOAD: There can be different impact forces on the bone and implant interface based on the direction of the load applied even if it’s of same magnitude of force. The implant is mainly designed for long axis load . A study was reported by Binderman in 1970 , where 50 endosteal implant designs were assessed and found that all the design sustained lesser bone loss under a long axis load. Binderman I.NIH- grant study on 2 dimentional FEA study of 54 implant body designs, 1973 (personal communication

27. The greater the angle of load to the implant long axis, the greater the compressive, tensile and shear stresses which leads to bone loss and unsuccessful bone re growth. Carl E Misch – Dental implant prosthodontics 3 rd edition

28. 7. CROWN HEIGHT Implant crown height is often greater than the natural anatomical crown. As the implant crown height becomes greater, the crestal moment with any lateral component of force also becomes greater. The angled load on an implant crown is at greater risk to the crestal bone than the implant angled body because the crown height act as a vertical cantilever. Carl E Misch – Dental implant prosthodontics 3 rd edition

29. So, whatever load is applied to the occlusal table, is magnified by the crown height. A 12 degree angled load of 100 N on an implant crown results with a 21-N additional loads as a lateral force component. However , if the crown is 15mm high, the final load to the crest of the bone is 21 N x 15mm = 315-Nmm moment force Carl E Misch – Dental implant prosthodontics 3 rd edition

30. The optimum height of prosthesis is considered to be 8-12 mm. 3mm soft tissue covering the collar of an implant along with the biological width 2mm thickness of the porcelain & average height of the abutment as 5mm. crown implant ratio between 0.5 and 2 show a favorable prognosis and can be maintained successfully if other prosthetic principles are equally taken into consideration. Dr. Rupal Jhanji "Crown-Implant Ratio versus Crown-Root Ratio – A Review.‖ IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) , vol. 17, no. 2, 2018, pp. 66-71.

31. 8. CANTILEVER: Cantilevers with unfavorable crown or implant ratio, increase the amount of stress to the implant These can further lead to peri implant bone loss and prosthesis failure The magnitude of load obtained by the implants is approximately proportional to the length of the cantilevers but it also varies with the implant number, spacing, and location

32. A cantilever may be considered a Class 1 lever : W hatever force is applied to the cantilever, a force twice as great will be applied to the farthest abutment from the cantilever. The force on the cantilever is a compressive force , whereas the force to the distal abutment is a tensile force . Yogeshwari , Gururaj Rao . Implant protected occlusion. IOSR Journal of dental and medical sciences- 2013

33. 9. OCCLUSAL CONTACT POSITION: Occlusal contact position determines the direction of force especially during parafunctional activity Peter K Thomas suggest that there should be tripod contact on each occluding cusp, on each marginal ridge and central fossa with 15-18 individual occlusal contacts on a mandibular and maxillary molars

34. An occlusal contact on a buccal cusp may create an offset load when the implant is under the central fossa and the buccal cusp is cantilevered from the implant body.

35. The central fossa is the logical primary occlusal contact position. The central fossa of an implant crown should be 2 to 3 mm wide in posterior teeth and parallel to the occlusal plane. Carl E Misch – Dental implant prosthodontics 3 rd edition

36. 10. Implant crown contour A wide occlusal table favors offset contacts during mastication or parafunction . Wider root form implants can accept a broader ranger of vertical occlusal contacts while still transmitting lesser forces at the per-mucosal site under offset loads. Therefore in IPO the width of the occlusal table is directly related to the width of the implant body.

37. wider the occlusal table, the greater the force developed by the biologic system to penetrate the bolus of food. The restorations mimicking the occlusal anatomy of the natural teeth often result in offset loads , complicated homecare and increased risk of porcelain fracture. As a result in non-esthetic regions of the mouth, the occlusal table should be reduced in width compared with natural teeth. 38 Carl E Misch – Dental implant prosthodontics 3 rd edition

38. PARAFUNCTION: BRUXISM PARAFUNCTION CLENCHING POOR OCCLUSLAL DESIGN BONE LOSS AND IMPLANT FAILURE

39. In patients with parafunctional habits, the overload can be greatly reduced by, Shorter cantilevers Ridge augmentation Reduction in height of crown By increasing soft tissue support Night guard protection

40. OCCLUSAL PRINCIPLES FOR DIFFERENT CLINICAL SITUATION

41. Clinical situation Occlusal principle Full arch fixed prosthesis Bilateral balanced occlusion with opposing complete denture Group functional occlusion or mutually protected occlusion with shallow anterior guidance when opposing natural dentition No working and balancing contact on cantilever Infraocclusion in cantilever segment (100µm) Freedom in centric (1- 1.5mm)

42. Clinical situation Occlusal principle Over dentures Bilateral balanced occlusion using lingualized occlusion Monoplane occlusion on severely resorbed ridge Posterior Fixed prosthesis Anterior guidance with natural dentition Group function occlusion with compromised canine Centererd contact, narrow occlusal table, flat cusp, minimized cantilever Cross bite posterior occlusion wherever necessary

43. Clinical situation Occlusal principle Single implant Prosthesis Anterior or lateral guidance with natural teeth Light contact at heavy bite and no contact at light bite Centered contact (1-1.5mm flat area) No offset contact Poor quality of bone/ Grafted bone Increased proximal contact Longer healing time Progressive loading by staging diet

44. SINGLE IMPLANT RESTORATIONS The occlusion in single implant should be designed to minimize occlusal force on to the implant and to maximize force distribution to adjacent natural teeth. In centric occlusion, the implant supported crown should have a clearance of 30  m . The clearance is important since the natural teeth can be intruded in their sockets under heavy loads whereas the implant retained prosthesis will not intrude . Failure to build in this appropriate occlusal clearance would expose the implant retained fixed prosthesis to excessive forces under heavy loading conditions. 45 Occlusion in implant dentistry. A review of the literature of prosthetic determinants and current concepts MD Gross Australian Dental Journal 2008;

45. Any anterior & lateral guidance should be obtained in natural dentition. Working & non-working contacts should be avoided. Light contacts on heavy bite & no contact in MIP 2 implants for a single molar demonstrated less screw loosening and higher success rates ( Balshi et al 1996) Instead of 2 implants , a wide diameter implant could be a better option to reduce surgical & prosthetic difficulties and to improve oral hygiene and loading condition. 46

46. Occlusion on full arch fixed prosthesis Opposing complete denture – BBO N atural dentition - group function MPO was also recommended for opposing natural dentition.( Hobo et al 1989 ) Bilateral & antero -posterior simultaneous contacts in centric occlusion and MIP should be obtained to evenly distribute occlusal force during excursions regardless of the occlusal scheme ( Chapman 1989; Lundgren & Laurell 1994 ) 47 Occlusion in implant dentistry. A review of the literature of prosthetic determinants and current concepts MD Gross Australian Dental Journal 2008;

47. Occlusion on overdentures BBO with lingualized occlusion on a normal ridge . Monoplane occlusion – severely resorbed ridge peroz et al performed a randomized clinical trial comparing 2 occlusal schemes, BBO & canine guidance in 22 patients with conventional complete dentures. The results of the assessment using a visual analog scale revealed that canine guidance was equally comparable to balanced occlusion in denture retention, esthetic appearance and chewing ability. 48 Occlusion in implant dentistry. A review of the literature of prosthetic determinants and current concepts MD Gross Australian Dental Journal 2008;

48. Occlusion on posterior fixed prosthesis Anterior guidance in excursions and initial occlusal contact on natural dentition will reduce the potential lateral force on osseointegrated implants. Group function should be utilized only when anterior teeth are periodontally compromised. During lateral excursions, working and non-working interferences should be avoided. Reduced inclination of cusps, centrally oriented contacts with 1-1.5mm flat area, narrowed occlusal table and elimination of cantilevers 49

49. Wennerberg & jemt (1999) described that additional implants in the maxilla could provide tripodism to reduce overloading and clinical complications. Axial positioning and reduced distance between posterior implants are important factors to decrease overloading. If the number, position, and axis of implants are questionable, natural tooth connection with a rigid attachment can be considered to provide additional support to implants. ( Rangert et al 1991) 50 Kim Y, Oh T-J, Misch CE- Wang H-L. Occlusal considerations in implant therapy, clinical guidelines with biomechanical rationale. Clin , Oral Impl 2005.

50. Occlusal materials Occlusal materials may be evaluated by esthetics, impact force, a static load, chewing efficiency, fracture wear, interarch space requirements, and accuracy of castings. The three most common groups of occlusal materials are porcelain, acrylic and metal. PEEK(Polyether ether ketone) as an occlusal material. Skalak explained, “A stiff prosthesis is preferable over a flexible one in the superstructure which is supported by osseointegrated implants and will distribute loads more effectively to the supporting abutments. 51

51. The use of a shock-absorbing material , such as acrylic resin in the form of artificial teeth on the surface of the denture, can provide adequate shock protection to the stiff and close connection of an osseointegrated implant to supporting bone. To reduce such peak forces, energy should be diffused by a layer of softer material placed in the path of the force transmission. Resin, in the form of plastic teeth , has a much lower modulus of elasticity than metals and provides internal damping to reduce the impact forces. 52

52. Yogeshwari , Gururaj Rao . Implant protected occlusion. IOSR Journal of dental and medical sciences- 2013

53. RECENT ADVANCES: PEEK(Polyether ether ketone) as an occlusal material. It has been observed that the PEEK material can reduces the stresses caused by the force applied or load.

54. Potential complications & solutions IMPLANT OVERLOAD Screw loosening Screw fractures Fractures of veneering materials Prothesis fractures Marginal bone loss below the first thread along the implant Implant fracture Implant loss

55. Can be prevented by application of sound bio-mechanical principles Passive fit of the prosthesis Reducing cantilever length Narrowing the B-L dimension of the prosthesis Reducing cusp inclination Eliminating excursive contacts Centering occlusal contacts 56

56. SUMMARY

57. 59

58. Implant occlusion 60

59. CONCLUSION: The objectives of implant occlusion are to minimize overload on the bone-implant interface and implant prosthesis, to maintain implant load within physiological limits of individualized occlusion, and finally to provide long term stability of implants and implant prosthesis. Currently, there is no evidence based, implant-specific concept of occlusion. Future studies in this area needed to clarify the relationship between occlusion and implant longevity.