title: Examination of ceramic/enamel interfacial debonding using acoustic emission and optical coherence tomography.
abstract: OBJECTIVE
  This study investigates monitored micro-crack growth and damage in the ceramic/enamel adhesive interface using the acoustic emission (AE) technique with optical coherence tomography (OCT) under fatigue shear testing.
  
  
  METHODS
  Shear bond strength (SBS) was measured first with eight prepared ceramic/enamel adhesive specimens under static loads. The fatigue shear testing was performed with three specimens at each cyclic load according to a modified ISO14801 method, applying at 80%, 75%, 70%, and 65% of the SBS to monitor interface debonding. The number of cycles at each load was recorded until ceramic/enamel adhesive interface debonding occurred. The AE technique was used to detect micro-crack signals in static and fatigue shear bond tests.
  
  
  RESULTS
  The results showed that the average SBS value in the static tests was 18.07 ± 1.72 MPa (mean ± standard deviation), expressed in Newton's at 56.77 ± 5.40N. The average number of fatigue cycles in which ceramic/enamel interface damage was detected in 80%, 75%, 70% and 65% of the SBS were 41, 410, 8141 and 76,541, respectively. The acoustic behavior varied according to the applied load level. Events were emitted during 65% and 70% fatigue tests. A good correlation was observed between the crack location in OCT images and the number of AE signal hits.
  
  
  CONCLUSIONS
  The AE technique combined with OCT images as a pre-clinical assessment tool to determine the integrity of cemented load bearing restored ceramic material. Sustainable cyclic load stresses in ceramic/enamel bonded specimens were substantially lower than the measured SBS. Predicted S-N curve showed that the maximum endured load was 10.98 MPa (about 34.48 N) passing 10(6) fatigue cyclic.
authors: Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan. Electronic address: cllin2@ym.edu.tw.
authors: Chun-Li
authors: CL
authors: Lin
authors: Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan. Electronic address: wckuo@ym.edu.tw.
authors: Wen-Chuan
authors: WC
authors: Kuo
authors: Department of General Dentistry, Chang Gung Memorial Hospital, Tao-yuan, Taiwan. Electronic address: cgucaeb@yahoo.com.tw.
authors: Yen-Hsiang
authors: YH
authors: Chang
authors: Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan. Electronic address: e198402019@yahoo.com.tw.
authors: Jin-Jie
authors: JJ
authors: Yu
authors: Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan. Electronic address: lucy0126@hotmail.com.tw.
authors: Yun-Chu
authors: YC
authors: Lin
mesh_terms: D000162:Acoustics; D002516:Ceramics; D017005:Dental Debonding; D003743:Dental Enamel; D003799:Dental Stress Analysis; D006801:Humans; D066298:In Vitro Techniques; D033081:Shear Strength; D041623:Tomography, Optical Coherence
keywords: Acoustic emission; Ceramic; Enamel; Fatigue; Optical coherence tomography