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Meditech Meeting on: “Innovations in Materials and Manufacturing of Dental Devices”

Cardiff MediCentre, 29th March 2007. Meditech Meeting on: “Innovations in Materials and Manufacturing of Dental Devices”. Thermal-mechanical reliability of Ti/HAp-based endosseous dental implant in severe conditions of Bruxism Giuseppe Cevola. Outline. Introduction 3D FEM Modelling

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Meditech Meeting on: “Innovations in Materials and Manufacturing of Dental Devices”

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  1. Cardiff MediCentre,29th March 2007 Meditech Meeting on: “Innovations in Materials and Manufacturing of Dental Devices” Thermal-mechanical reliability of Ti/HAp-based endosseous dental implant in severe conditions of Bruxism Giuseppe Cevola

  2. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical Studying & Bruxism conditions • Conclusions and future developments

  3. Introduction Bruxism is a disorder of the masticatory system characterized by teeth grinding and clenching Bruxism is considered • aetiological factor for temporomandibular disorders (TMD) • tooth wear (attrition) • loss of periodontal support • failure of dental restorations

  4. Introduction The most common current dental implants are: Sub-PERIOSTEAL ENDOSSEOUS

  5. Introduction Endosseous dental implant performance requirements: • biocompatibility: osteointegration • thermal/mechanical reliability: residual stress due to • production (Hot Isostatic Pressing, Spark Sintering)

  6. Introduction • The success of the endosseous dental implant integration is due to: • Lack of clinical signs and symptoms of pathology • Lack of mobility • Radiographically stable interface Radiographically stable interface • Dynamic Modeling process • Remodeling process Adaptive capacity: load-bearing biological structures that bond with bone Clark M. Stanford Biomechanical and functional behavior of implants Adv Dent Res 13:88-92, June, 1999

  7. Introduction Used Materials • Titanium and its alloys • Bioceramics : Hydroxyapatite (HAp) as coating, Zirconia Groundbreaking dental implants are designed using Functionally Graded Materials (FGM’s) made of Ti/HAp – Graduality along vertical direction: • Titanium: upper part (occlusive loading) • HAp: lower part (bone contact)

  8. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical studying & Bruxism conditions • Conclusions and future developments

  9. Modelling 3DFEM models FGM’s endosseous dental implant (first lower molar) Mandibular bone segment (35.25 mm) obtained by Computed Tomography (CT) images of Titanium dental implant (Bioform®) Computed Tomography (CT) images of Human mandibular bone

  10. Modelling Mandible Computed Tomography image

  11. Modelling Completed Model The materials are supposed isotropic with linear-elastic behaviour Toparli M, Sasaki S. Finite element analysis of the temperature and thermal stress in a postrestored tooth. J Oral Rehabil 2003;30:921–926.

  12. Modelling Mesial-Distal section Buccal-Lingual section • Higher peri-implant tensile and compressive stresses would imply: • implant-bone bond failure • bone absorption S.C.Huang, C.F.Tsai Finite element analysis of a dental implant Biomedical Engineering-Applications, Basis & communications Vol.15 No.2 April 2003 • Implant mechanical performances are evaluated by means peri-implant-bone stresses: • von Mises stress • First principal stress • Third principal stress

  13. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical Studying & Bruxism conditions • Conclusions and future developments

  14. Mechanical loading conditions:Experimental data Normal bilateral occlusive loading: Molar region : 400-650 N Premolar region : 222-445 N Canine region : 133-334 N Incisive region : 89-111 N K.J. Anusavice, Phillips Science of Dental Materials, W.B.Saunders Co., New York, (1996) Molar region unilateral occlusive loading : 30% smaller than one obtained during bilateral loading TWENTY-SECOND BIENNIAL MEETING 7–10 June 2001, Lugano, Switzerland Journal of Oral Rehabilitation 2002 29; 872–889 Upper and lower dental appliances containing miniaturestrain-gauge transducers.

  15. Mechanical loading conditions:Experimental data Bruxist bilateral clenching loading molar region : 790 N transversal force: 50 N First lower molar Journal of Oral Rehabilitation 2001 28; 485-491 K. Nishigawa Department of Fixed Prosthodontics, The University of Tokushima School of Dentistry, Tokushima, Japan

  16. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical Studying & Bruxism conditions • Conclusions and future developments

  17. FGMs composition’s parametric studying Exponential law between composition and longitudinal coordinate h = hydroxyapatite t = titanium Increasing value of Ti along the implant lenght

  18. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical Studying & Bruxism conditions • Conclusions and future developments

  19. m=0.1 m=0.2 m=0.5 m=1 m=2 m=5 m=10 Ti Thermal-mechanical Studying Changing temperature implant performances: ΔT = 0°C

  20. m=0.1 m=0.2 m=0.5 m=1 m=2 m=5 m=10 Ti Thermal-mechanical Studying Changing temperature implant performances: ΔT = 0°C

  21. Thermal-mechanical Studying Changing temperature implant performances: ΔT= + 20°C and -20°C

  22. Thermal-mechanical Studying Changing temperature implant performances: ΔT= + 20°C and -20°C

  23. Thermal-mechanical Studying Bruxism Conditions: Clenching load & grinding force

  24. Outline • Introduction • 3D FEM Modelling • mandibular bone • FGMs (Functionally Graded Materials) endosseous dental implant • Mechanical loading conditions • occlusive loading • bruxism loading • FGMs composition’s parametric studying • Thermal-mechanical Studying & Bruxism conditions • Conclusions and future developments

  25. Conclusions and future developments So far m = 2 composition withstands the highest von Mises and first principal stresses in all the implants, with temperature reduction of 20°C In progress On the basis of provided experimental data (K. NISHIGAWA School of Dentistry, Tokushima, Japan ) the bruxism behaviour is in progress Future works Would be desirable to carry-out fatigue analysis for the implant-bone bond The residual stresses due to the technological processes can neglect the hosting oral changing temperature effect?

  26. Acknowledgment • Dr. WANG Fang, PhD. Institute of High Performance Computing Singapore, • External Advisor • Prof. Estevam Barbosa de Las Casas, Universidade Federal de Minas Gerais, • Belo Horizonte, BRASIL • Prof. K. Nishigawa, School of Dentistry, Tokushima, Japan • Prof. F. Lobbezoo, Department of Oral function, Academic Centre for Dentistry • Amsterdam (ACTA), Amsterdam, The Netherlands • Are gratefully acknowledged for their assistance and contributions • Prof. Roberto Contro, Prof. of Biomechanics, Politecnico di Milano, Italy • Prof. Pasquale Vena, Assoc. of Biomechanics, Politecnico di Milano, Italy • Dr. Dario Gastaldi, PhD. of Material Engineering, Politecnico di Milano, Italy • Are also acknowledged for their kind assistance and useful discussions

  27. Thankyou!

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