Citation Information :
Narayankar A, Aswal GS, Ahmed S, Kumar V, Rawat R, Prabhakar N. Stress Distribution Patterns Associated with Dental Implants with Varying Thread Designs, Dimensions and Splinting Conditions: A Photoelastic Analysis. World J Dent 2022; 13 (1):9-15.
Aims and objectives: To assess and compare the functional load distribution pattern in dental implants with different thread designs (V-shaped, square, and reverse buttress), length (long = 12–13 mm, short = 8 mm), diameter (narrow = 3.75 mm, wide = 4.9–5 mm), and splinting condition (splinted or non-splinted) using photoelastic analysis.
Materials and methods: Eight epoxy resin-based photoelastic models using a custom-designed acrylic mould measuring 75 mm × 12 mm × 30 mm were prepared, with three implants in each of the models. Dental implants were placed vertically and parallel to each other using a holding device and a surveyor. A polariscope was employed to view the fringes before and after applying the load. Fringe orders were observed and principal stress was calculated. Data was statistically analyzed using factorial ANOVA.
Results: In splinted and non-splinted conditions, the least principal stress (1.111–2.286 N/fringe/mm2 and 1.363–3.082 N/fringe/mm2, respectively) was associated with V thread dental implants. Square thread (splinted 1.814–2.852 N/fringe/mm2, non-splinted 1.866–3.336 N/fringe/mm2) and reverse buttress thread (splinted 1.981–3.040 N/fringe/mm2, non-splinted 1.971–3.586 N/fringe/mm2) dental implants showed comparatively higher stress. Long and wide dental implants showed lesser principal stress when compared to short and narrow dental implants. Splinted dental implants presented lesser principal stress (2.021 N/fringe/mm2) in comparison to non-splinted dental implants (2.731 N/fringe/mm2).
Conclusions: Thread design, dimension and splinting condition of the implants plays a significant role in reducing bone stress. Clinically, to enhance the long-term success of implant therapy, V thread design, longer (≥12–13 mm) and wider (≥4.9–5 mm) implants shall be preferred over square or reverse buttress thread design, shorter (≤8 mm) and narrower (≤3.75 mm) implants. Splinting of dental implants effectively reduces principal stresses in the surrounding bone.
Clinical significance: Clinicians shall be able to use the findings of this study when selecting dental implants based on thread design, dimension, and the need to splint the dental implants for predictable treatment outcomes.
Soncini M, Rodriguez Y, Pietrabissa R, et al. Experimental procedure for the evaluation of the mechanical properties of the bone surrounding dental implants. Biomaterials 2002;23:9–17. DOI: 10.1016/s0142–9612(01)00073–4
Robinson D, Aguilar L, Gatti A, et al. Load response of the natural tooth and dental implant: a comparative biomechanics study. J Adv Prosthodont 2019;11(3):169–178. DOI: 10.4047/jap.2019.11.3.169
Álvarez-Arenal Á, Segura-Mori L, Gonzalez-Gonzalez I, et al. Stress distribution in the transitional peri-implant bone in a single implant-supported prosthesis with platform-switching under different angulated loads. J Odontol 2017;105(1):68–75. DOI: 10.1007/s10266–016-0237–6
Steigenga JT, Al-Shammari KF, Nociti FH, et al. Dental implant design and its relationship to long term implant success. Implant Dent 2003;12:306–317. DOI: 10.1097/01.id.0000091140.76130.a1
Herekar MG, Patil VN, Mulani SS, et al. The influence of thread geometry on biomechanical load transfer to bone: a finite element analysis comparing two implant thread designs. Dent Res J (Isfahan) 2014;11(4):489–494. PMID: 25225563; PMCID: PMC4163828.
Kong L, Liu B, Li D, et al. Comparative study of 12 thread shapes of dental implant designs: a three-dimensional finite element analysis. World J Model Simul 2006;2(2):134–140. Corpus ID: 16745111.
Corrêa C, Ribeiro A, Reis JM, et al. Photoelasticity in dentistry: a literature review. Medicine 2014;11(2):178–184. Available at: .
Ueda C, Markarian RA, Sendyk CL, et al. Photoelastic analysis of stress distribution on parallel and angled implants after installation of fixed prostheses. Braz Oral Res 2004;18(1):45–52. DOI: 10.1590/s1806–83242004000100009
Yacoub N, Ismail YH, Mao JJ. Transmission of bone strain in the craniofacial bones of edentulous human skulls upon dental implant loading, J Prosthet Dent 2002;88:192–199. DOI: 10.1067/mpr.2002.127401
Frost HM. Bone “mass” and the “mechanostat”: a proposal. Anat Rec 1987;219(1):1–9. DOI: 10.1002/ar.1092190104
Faegh S, Mechanism of load transfer along the bone-dental implant interface, Mechanical Engineering Master's Thesis, Paper 18. 2009. http://hdl.handle.net/2047/d20000013
Geng JP, Ma QS, Xu W, et al. Finite element analysis of four thread form configurations in a stepped screw implant. J Oral Rehabil 2004;31:233–1239. DOI: 10.1046/j.0305–182X.2003.01213.x
Lin CL, Kuo YC, Lin TS. Effects of dental implant length and bone quality on biomechanical responses in bone around implants: a 3D non-linear finite element analysis. Biomed Eng Appl Basis Comm 2005;17:44–49. DOI: 10.4015/S1016237205000081
Li T, Hu K, Cheng L, et al. Optimum selection of the dental implant diameter and length in the posterior mandible with poor bone quality-A 3D finite element analysis. Appl Math Model 2011;35:446–456. DOI: 10.1016/j.apm.2010.07.008
Elsayed MD. Biomechanical factors that influence the bone-implant interface. Res Rep Oral Maxillofac Surg 2019;3:23. DOI: 10.23937/IAOMS-2017/1710023
Grossman Y, Finger IM, Block MS. Indications for splinting implant restorations. J Oral Maxillofac Surg 2005;63:1642–1652. DOI: 10.1016/j.joms.2005.05.149
Nissan J, Ghelfan O, Gross M, et al. Analysis of load transfer and stress distribution splinted and unsplinted implant-supported fixed cemented restorations. J Oral Rehabil 2010;37:658–752. DOI: 10.1111/j.1365–2842.2010.02096.x
Jofre J, Cendoya P, Munoz P. Effect of splinting mini-implants on marginal bone loss: a biomechanical model and clinical randomized study with mandibular overdentures. Int J Oral Maxillofac Implants 2010;25(6):1137–1144.
Guichet DL, Caputo AA, Choi H, et al. Passivity of fit and marginal opening in screw or cement retained implant fixed partial denture designs. Int J Oral Maxillofac Implants 2000;15:239–246. PMID: 10795456.
De Souza Batista VE, Verri FR, Lemos CAA, et al. Should the restoration of adjacent implants be splinted or non-splinted? A systematic review and meta-analysis. J Prosthet Dent 2019;121(1):41–51. DOI: 10.1016/j.prosdent.2018.03.004
Vigolo P, Mutinelli S, Zaccaria M, et al. Clinical evaluation of marginal bone level change around multiple adjacent implants restored with splinted and non-splinted restorations: a 10-year randomized controlled trial. Int J Oral Maxillofac Implants 2015;30(2):411–418. DOI: 10.11607/jomi.3837