Comparative biomechanical analyses for kennedy’s class-I cast partial denture using acrylic denture base with Co-Cr I bar and nylon denture base with nylon retentive clasp-A 3D finite element study
Introduction: The goal of present PRPD is to optimize esthetics with denture design that ensures minimal invasion to the remaining oral tissues, since the function of an PRPD is affected by physical properties of direct retainers. A comparative 3-D Finite Element (FE) stress analysis for mandibular Kennedy’s class-I situation using two different denture base and direct retainer material on distal abutment was done Method: FE models were developed, with simulated alveolar bone, mucosa, abutments, periodontal ligaments, framework and artificial teeth in the models. The 2 FE models, Model A having PMMA denture base and Co-Cr gingival approaching clasp and Model B having nylon denture base and retentive clasp made up of nylon only were developed. Structural analysis for two designs was carried out using ANSYS FEA software. Results: During analysis static distributed load of 150N over artificial teeth vertically and 45ᵒ diagonally was applied. The stresses and deformation produced in assembly were evaluated Structural analysis results were analyzed for various supporting structures. The two designs showed considerable differences in stresses and displacement developed in supporting structures. Cast partial denture with nylon direct retainer and denture base showed greater stresses and displacement than acrylic denture base and Co-Cr clasp on diagonal loading whereas on vertical loading it showed almost similar displacement but slightly greater stresses. Conclusion: The results of this study suggest the use of nylon as denture base and direct retainer in esthetic region for class I situation as it generate favorable biomechanical stress, being all values are under the physiologic limit.
2. Watt DM. Clinical assessment of nylon as a partial denture base material. Br Dent J 1955;98:238-44.
3. MacGregor AR, Graham J, Stafford GD, Huggett R. Recent experiences with denture polymers. J Dent 1984;12:146-57
4. Hamanaka I, Takahashi Y, Shimizu H. Mechanical properties of injection-molded thermoplastic denture base resins. Acta Odontol Scand 2011;69:75-9.
5. Masayasu Ito,a Alvin G. Wee, BDS, Takanari Miyamoto, and Yasuhiko Kawai, MMedSci, The combination of a nylon and traditional partial removable dental prosthesis for improved esthetics: A clinical report. J Prosthet Dent 2013;109:5-8
6. Sato, K.Stuga, Y.Abe, S.Asahara and Y.Akagawa. Analysis of stiffness and stress in I-bar clasps. J. Oral Rehab 2001; 28:596-600.
7. S.N Bhaskar. Orbans textbook of oral histology and embryology. CBS publication.10th edition. Page-240.
8. Y.Sato,M.Wadamota,K.Tsuga, E.R.Teixeira. The effectiveness of element downsizing on a three-dimensional finite element model of bone trabeculae in implant biomechanics. J.Oral rehab 1999;26:288-291
9. Yatabe M: Study on measurement of dynamic viscoelasticity of maxillary mucosa.[ in Japanese]. Kokubyo Gakkai Zasshi 1991;58:74-94
10. Gilbert J. Paritt. Measurement of the Physiological mobility of individual teeth in an axial direction. J.D.Res 1960;39(3):608-618.
11. Wayne D.Thompson, F.james Kratochvil & Angelo A. Caputo. Evaluation of photoelastic stress patterns produced by various designs of bilateral distal-extension removable partial dentures. JPD 2004 ;91 :105-13
12. Arthur.R frechette. The influence of partial denture design on distribution of force to abutment teeth. JPD 2001;85 :527-539.
13. Anthony K. Kaires. Partial denture design and its relation to force distribution and masticatory performance. JPD 1956;4(5):672-683.
14. Oliver C. Applegate. An evaluation of the support for the removable partial denture. JPD 1960;10(1):112-123.
15. Cecconi BT, AsgarK, Dootz E: Clasp assembly modifications and their effect on abutment tooth mobility. J Prosthet Dent 1972;27:160-167
16. Kratochvil FJ: Influence of occlusal rest position and clasp design on movement of abutment tceth. JPD 1963;13:11-C-124
17. Thompson WU, Kratochd FJ, Caputo A.4: Evaluation of photoelastic stress patterns produced by various designs of bilateral distal extension removable partial dentures. J Prosthet Dent 1977;38:261-273
18. Jean C. Wu, George H. Latta, Rusell A. Wicks, Robert L. Swords and Mark Scarbecz. In vitro deformation of acetyl resin and metal alloy removable partial denture retainers. JPD 2003;90:586-590.
19. Robert B. Lytle. Soft tissue displacement beneath removable partial and complete dentures. JPD 1962;12(1);34-43.
20. McGivney GP, Castleberry DJ: Principles of removable partial denture design In McCracken’s Removable Partial Prosthodontics (ed 9). St. Louis, Mosby, 1995,pp 160- 188.
21. Seiji Wada, Noriyuki Wakabayashi, Takehisa Tanaka, and Takashi Ohyama. Influence of Abutment Selection in Maxillary Kennedy Class II RPD on Elastic Stress Distribution in Oral Mucosa: An FEM Study. J Prosthodont 2006;15:89-94