Measurements of mechanical properties and morphology of root canal in maxillary primary anterior teeth

doi:10.7518/hxkq.2017.04.010

Abstract

Abstract:

Objective This study aimed to measure the taper and diameter of root canal, as well as the elastic modulus and hardness in the root dentin of maxillary primary anterior teeth. Methods Patients under general anesthesia who needed root canal therapy in the maxillary primary anterior teeth were selected. Silicone impression material was used to take impressions. The impressions were scanned, and the taper and diameter of root canal were measured. Maxillary primary anterior teeth were collected in vitro. The elastic modulus and hardness of root dentin was tested. Results A total of 74 silicone impressions were obtained. The mean tapers of primary incisor teeth, primary lateral incisor teeth, and primary canine teeth were 0.106, 0.185, and 0.098, respectively. The mean diameters of the root canal 5 mm below the cementum-enamel junction (CEJ) were 1.267, 0.860, and 1.429 mm, respectively. The elastic modulus and hardness of root dentin were measured in 10 primary anterior teeth in vitro. The range of elastic modulus was 19.919-25.017 GPa. The range of hardness was 0.867-1.082 GPa. Conclusion The root canal post used in primary anterior teeth can be produced by the following data: taper of primary incisor teeth and primary canine teeth, 0.1; diameters of their tips, 1.2 mm and 1.4 mm, respectively; taper of primary lateral incisor teeth, 0.2; diameter of their tips, 0.8 mm; range of elastic modulus, 20-25 GPa; and range of hardness, 0.87-1.08 GPa.

Key words: primary teeth, taper, diameter of root canal, root dentin, elastic modulus, hardness

CLC Number:

R788

Jia Hu, He Liu, Qing Cai, Xuliang Deng. Measurements of mechanical properties and morphology of root canal in maxillary primary anterior teeth[J]. West China Journal of Stomatology, 2017, 35(4): 394-398.

Figures/Tables 6

Fig 1

Fig 2

Fig 3

Tab 1

Tab 2

Tab 3

References 19

[1]	邓辉, 徐征. 北京市1~4岁儿童龋流行情况调查及其危险因素的初步研究[J]. 现代口腔医学杂志, 2006, 20(4):418-421.
	Deng H, Xu Z.A primary study of early childhood caries and risk factors for 1 to 4-year-old children in Beijing[J]. J Modern Stomatol, 2006, 20(4):418-421.
[2]	Zemaitiene M, Grigalauskiene R, Andruskeviciene V, et al.Dental caries risk indicators in early childhood and their association with caries polarization in adolescence: a cross-sectional study[J]. BMC Oral Health, 2016, 17(1):2.
[3]	蔡晨星, 朱玲. 婴幼儿龋危险因素研究近况[J]. 牙体牙髓牙周病学杂志, 2011, 21(1):52-54.
	Cai CX, Zhu L.Risk factors of early childhood caries[J]. Chin J Conserv Dent, 2011, 21(1):52-54.
[4]	文玲英, 吴礼安. 实用儿童口腔医学[M]. 北京: 人民军医出版社, 2013:90-91.
	Wen LY, Wu LA.Practical pediatric dentistry[M]. Beijing: People’s Military Medical Publishing House, 2013:90-91.
[5]	陈旭, 丁振江. 早期婴幼儿龋[J]. 中国实用口腔科杂志, 2011, 4(1):1-4.
	Chen X, Ding ZJ.Early childhood caries[J]. Chin J Pract Stomatol, 2011, 4(1):1-4.
[6]	Borssén E, Stecksén-Blicks C.Risk factors for dental caries in 2-year-old children[J]. Swed Dent J, 1998, 22(1/2):9-14.
[7]	冀堃, 王茜, 邹艳萍, 等. 聚乳酸根管钉浸提液对人乳牙牙周膜细胞生物学性能的影响[J]. 临床口腔医学杂志, 2009, 25(9):515-518.
	Ji K, Wang X, Zou YP, et al.Effects of pla post extract liguid on biological characteristics of deciduous teeth periodontal ligament fibroblasts[J]. J Clin Stomatol, 2009, 25(9):515-518.
[8]	王茜, 冀堃, 邹艳萍, 等. 聚乳酸生物材料与人乳牙牙髓干细胞的生物相容性研究[J]. 牙体牙髓牙周病学杂志, 2009, 19(11):627-631.
	Wang X, Ji K, Zou YP, et al.Biocompatibility between polye-sters polylactide and stem cells from human exfoliated deci-duous teeth[J]. Chin J Conserv Dent, 2009, 19(11):627-631.
[9]	邹艳萍, 李石保, 冀堃, 等. 聚乳酸根管桩浸提液对人牙囊细胞生物学性能的影响[J]. 牙体牙髓牙周病学杂志, 2009, 19(10):567-570.
	Zou YP, Li SB, Ji K, et al.Effects of PLA post leaching liquor on biological characteristics of human dental follicle cells[J]. Chin J Conserv Dent, 2009, 19(10):567-570.
[10]	龙明生, 刘彩云, 杜昌连. 乳牙根管系统的形态研究[J]. 华西口腔医学杂志, 2011, 29(5):517-518.
	Long MS, Liu CY, Du CL.Root canal morphology of deci-duous tooth[J].West Chin J Stomatol, 2011, 29(5):517-518.
[11]	张丽文, 潘志文. 锥形束CT对乳磨牙根管形态的初步研究[J]. 口腔医学, 2013, 33(9):590-593.
	Zhang LW, Pan ZW.Preliminary study on root canal mor-phology of deciduous molars by CBCT[J]. Stomatology, 2013, 33(9):590-593.
[12]	柳雯, 杨柳, 许晓芳, 等. 显微与体视显微镜测量根管锥度的体外研究[J]. 口腔医学研究, 2008, 24(5):551-553.
	Liu W, Yang L, Xu XF, et al.In vitro study on taper of root canal with micro-computed tomography (MCT) and stereo-microscope[J]. J Oral Sci Res, 2008, 24(5):551-553.
[13]	冯海兰, 徐军. 口腔修复学[M]. 2版. 北京: 北京大学医学出版社, 2013:80.
	Feng HL, Xu J.Prosthodontics[M]. 2nd ed. Beijing: Peking University Medical Press, 2013:80.
[14]	Hosoya Y, Marshall GW.The nano-hardness and elastic modulus of sound deciduous canine dentin and young pre-molar dentin—preliminary study[J]. J Mater Sci Mater Med, 2005, 16(1):1-8.
[15]	Mahoney E, Holt A, Swain M, et al.The hardness and mo-dulus of elasticity of primary molar teeth: an ultra-micro-indentation study[J]. J Dent, 2000, 28(8):589-594.
[16]	Ryou H, Romberg E, Pashley DH, et al.Nanoscopic dynamic mechanical properties of intertubular and peritubular dentin[J]. J Mech Behav Biomed Mater, 2012, 7:3-16.
[17]	Angker L, Swain MV, Kilpatrick N.Micro-mechanical cha-racterisation of the properties of primary tooth dentine[J]. J Dent, 2003, 31(4):261-267.
[18]	陈湘涛, 李晓娜, 关振群, 等. 桩核材料对牙本质应力分布的影响[J]. 中华口腔医学杂志, 2004, 39(4):302-305.
	Chen XT, Li XN, Guan ZQ, et al.Effects of post material on stress distribution in dentine[J]. Chin J Stomatol, 2004, 39(4):302-305.
[19]	潘徽, 程灿, 胡嘉, 等. 聚乳酸可吸收根管桩与3种粘接剂的粘接强度[J]. 北京大学学报(医学版), 2015, 47(6):990-993.
	Pan H, Cheng C, Hu J, et al.Bond strengths of absorbable polylactic acid root canal post with three different adhesives[J]. J Peking Univ (Heal Sci), 2015, 47(6):990-993.

牙位	牙数	锥度	直径/mm
牙位	牙数	锥度	CEJ	CEJ下5 mm
乳中切牙	28	0.106±0.005 4	1.796±0.063 4	1.267±0.056 0
乳侧切牙	35	0.185±0.009 5	1.783±0.053 6	0.860±0.025 6
乳尖牙	11	0.098±0.007 3	1.921±0.094 6	1.429±0.084 4

测量位点		硬度/GPa	测量位点数
CEJ	外层	1.076±0.077	31
	中间层	1.082±0.085	31
	内层	0.963±0.079	26
CEJ下5 mm	外层	1.019±0.109	28
	中间层	1.029±0.103	28
	内层	0.867±0.103	27

测量位点		弹性模量/GPa	测量位点数
CEJ	外层	24.753±0.688	31
	中间层	25.017±0.800	31
	内层	22.183±0.674	26
CEJ下5 mm	外层	22.706±0.680	28
	中间层	23.084±0.727	28
	内层	19.919±0.729	27