Chinese Journal of Tissue Engineering Research ›› 2018, Vol. 22 ›› Issue (26): 4208-4214.doi: 10.3969/j.issn.2095-4344.0933

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Irradiation with erbium, chromium:yttrium scandium gallium garnet laser alters shear bond strength to primary tooth dentin

Liang Yun1, Shi Jian-jie2, Chen Ke3, Luo Zhen-shan1, Deng Wen-xin1   

  1. 1Liwan Hospital, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, Guangdong Province, China; 2the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong Province, China; 3Guangzhou Women and Children’s Medical Center, Guangzhou 510623, Guangdong Province, China
  • Received:2018-02-09
  • Contact: Shi Jian-jie, Chief physician, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, Guangdong Province, China
  • About author:Liang Yun, Master, Physician, Liwan Hospital, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, Guangdong Province, China
  • Supported by:

    the Natural Science Foundation of Guangdong Province, No. S2013010014879; the Science and Technology Research Plan of Guangzhou, No. 201510010160

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Abstract:

BACKGROUND: Pretreatment of dental hard tissues is critical for a success in tooth bonding repair.

OBJECTIVE: To explore the shear bond strength of nano-hybrid resin bonded to the primary tooth dentin after conditioning by 35% phosphoric acid, erbium, chromium:yttrium scandium gallium garnet (Er,Cr:YSGG) irradiation or their combined use.
METHODS: 120 extracted primary incisors with enamel removal were randomly divided into three groups and dealt with the following pretreatments: in control group (n=12), the tooth surface was without any processing; in acid etching group (n=12), the tooth surface was etched using 35% phosphoric acid; in laser group (n=48), the tooth surface was treated by Er,Cr:YSGG laser at four power outputs (1 W,   50 mJ, 20 Hz; 2 W, 100 mJ, 20 Hz; 3 W, 150 mJ, 20 Hz; 4 W, 200 mJ, 20 Hz); in combined group (n=48), the tooth surface was treated with 35% phosphoric acid followed by Er,Cr:YSGG laser irradiation at four power outputs (1 W, 50 mJ, 20 Hz; 2 W, 100 mJ, 20 Hz; 3 W, 150 mJ,  20 Hz; 4 W, 200 mJ, 20 Hz). Two samples from each group were randomly selected and observed using scanning electron microscope, and the residual samples were bonded with the composite resin for shear bonding strength test.

RESULTS AND CONCLUSION: (1) The shear bond strength of the dentine was lowest in the control group [(4.03±1.80) MPa], and highest in the 2 W laser group [(14.12±3.23) MPa], followed by the acid etching group [(13.11±3.23) MPa]. (2) Under the scanning electron microscope, the dentin surface of the control group was covered with a smear layer and debris. Dentin tubule of the acid etching group completely opened, with increased pipe diameter, the smear layer was removed presenting with the smooth surface on which only a little debris was seen, and no marked boundary existed between the pertitubular dentin and intertubular dentin. The dentin surface in the laser group was rugged and presented with fish scale-shaped flakes, the dentin tubule opened, and the intertubular dentin seemed to ablate more than the pertitubular dentin, showing a cuff-like protrusion of the dentinal tubules without smear layer. As the laser energy improved, blocking of the dentin tubule occurred, and some cracks and fractures appeared on the dentin surface. Fluctuant dentin surface was detected in the combined group, in which overall demineralization was higher and embolism and clogging of the dentin tubule was more prominent compared with the laser group. Overall, Er,Cr:YSGG laser ablation of the primary teeth, prior to the adhesive protocol, influences the shear bond strength to the primary tooth dentin and the best parameters for Er,Cr:YSGG laser are 2 W, 20 Hz, 100 mJ.

中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程

Key words: Dental Prosthesis, Lasers, Shear Strength, Tissue Engineering

CLC Number: