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A finite element analysis of the stress distribution to the mandible from impact forces with various orientations of third molars

有限元方法分析具有不同形态第三磨牙的下颌骨 受到冲击力时的应力分布

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Abstract

Objective

To investigate the stress distribution to the mandible, with and without impacted third molars (IM3s) at various orientations, resulting from a 2000-Newton impact force either from the anterior midline or from the body of the mandible.

Materials and methods

A 3D mandibular virtual model from a healthy dentate patient was created and the mechanical properties of the mandible were categorized to 9 levels based on the Hounsfield unit measured from computed tomography (CT) images. Von Mises stress distributions to the mandibular angle and condylar areas from static impact forces (Load I-front blow and Load II left blow) were evaluated using finite element analysis (FEA). Six groups with IM3 were included: full horizontal bony, full vertical bony, full 450 mesioangular bony, partial horizontal bony, partial vertical, and partial 450 mesioangular bony impaction, and a baseline group with no third molars.

Results

Von Mises stresses in the condyle and angle areas were higher for partially than for fully impacted third molars under both loading conditions, with partial horizontal IM3 showing the highest fracture risk. Stresses were higher on the contralateral than on the ipsilateral side. Under Load II, the angle area had the highest stress for various orientations of IM3s. The condylar region had the highest stress when IM3s were absent.

Conclusions

High-impact forces are more likely to cause condylar rather than angular fracture when IM3s are missing. The risk of mandibular fracture is higher for partially than fully impacted third molars, with the angulation of impaction having little effect on facture risk.

摘要

目的

评估下颌骨在具有不同形态的第三磨牙或者没有 第三磨牙的情况下,当遭受到前部或侧部2000 N 冲击力时,其应力分布。

创新点

第三磨牙的存在对下颌骨的力学性能有影响,而 且不同位置形态的第三磨牙对下颌骨的力学性 能的影响存在差异。

方法

根据一个具有完整牙列的健康下颌骨的计算机断 层扫描(CT)图像构建出其三维模型,以CT 图 像上的Hounsfield 值(HU)为基础,计算出下颌 骨的力学性能参数(包括密度和杨氏模量),共 分成9 组数据。构建出第三磨牙分别为水平向、 垂直向以及近中方向呈45 度角时的完全阻生和 部分阻生的共6 组下颌骨计算模型。并以无第三 磨牙的下颌骨为基准模型,利用有限元方法计算 在下颌前部和侧面分别受到2000 N 的静态冲击 力的情况下Von Mises 应力分布。

结论

有限元分析结果显示,相同载荷条件下,当第三 磨牙部分阻生时的下颌骨髁突颈和角部区域的 应力值比完全阻生时要大,因此具有部分阻生第 三磨牙的下颌骨具有更高的骨折风险;当具有水 平向部分阻生的第三磨牙时,下颌骨骨折的风险 最大。对于各种计算模型,下颌骨受到侧向冲击 力时,应力最大位置均位于下颌角区;对于无第 三磨牙的下颌骨,应力最大位置位于髁突颈部区 域,此时髁突颈更容易发生骨折。

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References

  • Afrooz PN, Bykowski MR, James IB, et al., 2015. The epidemiology of mandibular fractures in the United States, Part 1: a review of 13,142 cases from the US National Trauma Data Bank. J Oral Maxillofac Surg, 73(12): 2361–2365. https://doi.org/10.1016/j.joms.2015.04.032

    Article  PubMed  Google Scholar 

  • Antic S, Vukicevic AM, Milasinovic M, et al., 2015. Impact of the lower third molar presence and position on the fragility of mandibular angle and condyle: a three-dimensional finite element study. J Craniomaxillofac Surg, 43(6): 870–878. https://doi.org/10.1016/j.jcms.2015.03.025

    Article  PubMed  Google Scholar 

  • Bezerra TP, SilvaJr FI, Scarparo HC, et al., 2013. Do erupted third molars weaken the mandibular angle after trauma to the chin region? A 3D finite element study. Int J Oral Maxillofac Surg, 42(4): 474–480. https://doi.org/10.1016/j.ijom.2012.10.009

    Article  CAS  PubMed  Google Scholar 

  • Boffano P, Roccia F, 2010. Bilateral mandibular angle fractures: clinical considerations. Craniofac Surg, 21(2): 328–331. https://doi.org/10.1097/SCS.0b013e3181cf5fbc

    Article  Google Scholar 

  • Chrcanovic BR, Neto Custódio AL, 2010. Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature. Oral Maxillofac Surg, 14(2): 71–80. https://doi.org/10.1007/s10006-009-0201-5

    Article  PubMed  Google Scholar 

  • Cillo Jr JE, Ellis E, 2014. Management of bilateral mandibular angle fractures with combined rigid and nonrigid fixation. J Oral Maxillofac Surg, 72(1): 106–111. https://doi.org/10.1016/j.joms.2013.07.008

    Article  PubMed  Google Scholar 

  • Currey JD, 2002. Bones: Structure and Mechanics. Princeton University, Princeton, NJ.

    Google Scholar 

  • Donadille M, Vidal N, Ella B, et al., 2013. Biangular fractures of the mandible. Rev Stomatol Chir Maxillofac, 114(5): 287–291. https://doi.org/10.1016/j.revsto.2013.03.004

    CAS  Google Scholar 

  • Duan DH, Zhang Y, 2008. Does the presence of mandibular third molars increase the risk of angle fracture and simultaneously decrease the risk of condylar fracture? Int J Oral Maxillofac Surg, 37(1): 25–28. https://doi.org/10.1016/j.ijom.2007.07.010

    Article  CAS  PubMed  Google Scholar 

  • Duarte BG, Assis D, Ribeiro-Junior P, et al., 2012. Does the relationship between retained mandibular third molar and mandibular angle fracture exist? An assessment of three possible causes. Craniomaxillofac Trauma Reconstr, 5(3): 127–136. https://doi.org/10.1055/s-0032-1313355

    Article  PubMed  PubMed Central  Google Scholar 

  • Ethunandan M, Shanahan D, Patel M, 2012. Iatrogenic mandibular fractures following removal of impacted third molars: an analysis of 130 cases. Br Dent J, 212(4): 179–184. https://doi.org/10.1038/sj.bdj.2012.135

    Article  CAS  PubMed  Google Scholar 

  • Fuselier JC, Ellis III EE, Dodson B, 2002. Do mandibular third molars alter the risk of angle fracture? J Oral Maxillofac Surg, 60(5): 514–518. https://doi.org/10.1053/joms.2002.31847

    Article  PubMed  Google Scholar 

  • Gaddipati R, Ramisetty S, Vura N, et al., 2014. Impacted mandibular third molars and their influence on mandibular angle and condyle fractures—a retrospective study. J Craniomaxillofac Surg, 42(7): 1102–1105. https://doi.org/10.1016/j.jcms.2014.01.038

    Article  PubMed  Google Scholar 

  • Halazonetis JA, 1968. The ‘weak’ regions of the mandible. Br J Oral Surg, 6(1): 37–48. https://doi.org/10.1016/S0007-117X(68)80025-3

    Article  CAS  PubMed  Google Scholar 

  • Hanson BP, Cummings P, Rivara FP, et al., 2004. The association of third molars with mandibular angle fractures: a meta-analysis. J Can Dent Assoc, 70(1): 39–43.

    PubMed  Google Scholar 

  • Iida S, Hassefeld S, Reuther T, et al., 2005. Relationship between the risk of mandibular angle fractures and the status of incompletely erupted mandibular third molars. J Craniomaxillofac Surg, 33(3): 158–163. https://doi.org/10.1016/j.jcms.2004.12.001

    Article  PubMed  Google Scholar 

  • Kan B, Coskunses FM, Mutlu I, et al., 2015. Effects of interimplant distance and implant length on the response to frontal traumatic force of two anterior implants in an atrophic mandible: three-dimensional finite element analysis. Int J Oral Maxillofac Surg, 44(7): 908–913. https://doi.org/10.1016/j.ijom.2015.03.002

    Article  CAS  PubMed  Google Scholar 

  • Kumar SR, Sinha R, Uppada UK, et al., 2015. Mandibular third molar position influencing the condylar and angular fracture patterns. J Maxillofac Oral Surg, 14(4): 956–961. https://doi.org/10.1007/s12663-015-0777-2

    Article  Google Scholar 

  • Lee JT, Dodson TB, 2000. The effect of mandibular third molar presence and position on the risk of an angle fracture. J Oral Maxillofac Surg, 58(4): 394–398. https://doi.org/10.1016/S0278-2391(00)90921-2

    Article  CAS  PubMed  Google Scholar 

  • Ma'aita J, Alwrikat A, 2000. Is the mandibular third molar a risk factor for mandibular angle fracture? Oral Surg Oral Med Oral Pathol Oral Radiol, 89(2): 143–146. https://doi.org/10.1067/moe.2000.103527

    Article  Google Scholar 

  • Meisami T, Sandor GKB, Lawrence HP, et al., 2002. Impacted third molars and risk of angle fracture. Int J Oral Maxillofac Surg, 31(2): 140–144. https://doi.org/10.1054/ijom.2001.0215

    Article  CAS  PubMed  Google Scholar 

  • Mercier P, Precious D, 1992. Risks and benefits of removal of impacted third molars. A critical review of the literature. Int J Oral Maxillofac Surg, 21(1): 17–27. https://doi.org/10.1016/S0901-5027(05)80447-3

    Article  CAS  PubMed  Google Scholar 

  • Naghipur S, Shah A, Elgazzar RF, 2014. Does the presence or position of lower third molars alter the risk of mandibular angle or condylar fractures? J Oral Maxillofac Surg, 72(9): 1766–1772. https://doi.org/10.1016/j.joms.2014.04.004

    Article  PubMed  Google Scholar 

  • Pakdel A, Fialkov J, Whyne CM, 2016. High resolution bone material property assignment yields robust subject specific finite element models of complex thin bone structures. J Biomech, 49(9): 1454–1460. https://doi.org/10.1016/j.jbiomech.2016.03.015

    Article  PubMed  Google Scholar 

  • Rho JY, Hobatho MC, Ashman RB, 1995. Relations of mechanical properties to density and CT numbers in human bone. Med Eng Phys, 17(5): 347–355. https://doi.org/10.1016/1350-4533(95)97314-F

    Article  CAS  PubMed  Google Scholar 

  • Rice JC, 1988. On the dependence of the elasticity and strength of cancellous bone on the apparent density. J Biomech, 21(2): 155–168. https://doi.org/10.1016/0021-9290(88)90008-5

    Article  CAS  PubMed  Google Scholar 

  • Richard TH, Vincent VH, Nisra T, et al., 1992. Modeling the biomechanics of the mandible: a three-dimensional finite element study. J Biomech, 25(3): 261–286.

    Article  Google Scholar 

  • Ruffoni D, Fratzl P, Roschger P, et al., 2007. The bone mineralization density distribution as a fingerprint of the mineralization process. Bone, 40(5): 1308–1319. https://doi.org/10.1016/j.bone.2007.01.012

    Article  CAS  PubMed  Google Scholar 

  • Safdar N, Meechan JG, 1995. Relationship between fractures of mandibular angle and the presence and state of eruption of lower third molar. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 79(6): 680–684. https://doi.org/10.1016/S1079-2104(05)80299-9

    Article  CAS  PubMed  Google Scholar 

  • Singh P, Wang C, Ajmera DH, et al., 2016. Biomechanical effects of novel osteotomy approaches on mandibular expansion: a 3D finite element analysis. J Oral Maxillofac Surg, 74(8): 1658.

    Article  PubMed  Google Scholar 

  • Tevepaugh DB, Dodson TB, 1995. Are mandibular third molars a factor for angle fractures? A retrospective cohort study. J Oral Maxillofac Surg, 53(6): 646–650. https://doi.org/10.1016/0278-2391(95)90160-4

    Article  CAS  PubMed  Google Scholar 

  • Thangavelu R, Yoganandha R, Vaidhyanathan A, 2010. Impact of impacted mandibular third molars in mandibular angle and condyle fractures. Int J Oral Maxillofac Surg, 39(2): 136–139. https://doi.org/10.1016/j.ijom.2009.12.005

    Article  CAS  PubMed  Google Scholar 

  • Venta I, Murtomaa H, Turtola L, et al., 1991. Clinical follow-up study of third molar eruption from ages 20 to 26 years. Oral Surg Oral Med Oral Pathol, 72(2): 150–153. https://doi.org/10.1016/0030-4220(91)90154-5

    Article  CAS  PubMed  Google Scholar 

  • Weiner S, Wagner HD, 1998. The material bone: structure mechanical function relations. Ann Rev Mater Sci, 28(1): 271–298. https://doi.org/10.1146/annurev.matsci.28.1.271

    Article  CAS  Google Scholar 

  • Werkmeister R, Fillies T, Joos U, et al., 2005. Relationship between lower wisdom tooth position and cyst development, deep abscess formation and mandibular angle fracture. J Craniomaxillofac Surg, 33(3): 164–168. https://doi.org/10.1016/j.jcms.2005.01.011

    Article  PubMed  Google Scholar 

  • Xia ZY, Jiang FF, Chen J, 2013. Estimation of periodontal ligament’s equivalent mechanical parameters for finite element modeling. Am J Orth Dentofac Orthoped, 143(4): 486–491. https://doi.org/10.1016/j.ajodo.2012.10.025

    Article  Google Scholar 

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Correspondence to Yun-feng Liu.

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Project supported by the National Natural Science Foundation of China (Nos. 51375453 and 51775506) and the Natural Science Foundation of Zhejiang Province (No. LY18E050022), China

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Liu, Yf., Wang, R., Baur, D.A. et al. A finite element analysis of the stress distribution to the mandible from impact forces with various orientations of third molars. J. Zhejiang Univ. Sci. B 19, 38–48 (2018). https://doi.org/10.1631/jzus.B1600552

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  • DOI: https://doi.org/10.1631/jzus.B1600552

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