title: Application of optical coherence tomography to identify pulp exposure during access cavity preparation using an Er:YAG laser.
abstract: OBJECTIVE
  The study aimed to evaluate the ability of optical coherence tomography (OCT) to guide and identify pulp exposure using an erbium: yttrium-aluminum-garnet (Er:YAG) laser.
  
  
  BACKGROUND
  The Er:YAG laser has been proven to be effective in ablating dental hard tissue and offers advantages, as there is none of the vibration and noise you get with conventional methods, but it has limitations in relation to the tactile feedback that would aid in identification of entry into the pulp chamber. Based on depth-resolved optical reflectivity, OCT technology has been developed to provide high-resolution, cross-sectional images of the internal structure of biological tissues.
  
  
  METHODS
  The pulp chambers of 20 human mandibular incisors were examined, and the average thickness of hard tissue covering the pulp chamber was assessed using micro-computed tomography (micro-CT) images. An Er:YAG laser was used to gradually penetrate the hard tissue over the pulp chamber under microscopic guidance. The preparation was constantly imaged using a swept-source OCT at 10 sec intervals until a pulp chamber exposure was identified using the technology. The pulp exposure was re-examined under the microscope and compared with micro-CT images for verification.
  
  
  RESULTS
  The pulp exposures of 20 incisors were all verified microscopically and with micro-CT images. The thickness of hard tissue penetrated by the laser ranged from 0.44 to 1.69 mm.
  
  
  CONCLUSIONS
  Swept-source OCT is a useful tool for identifying pulp exposure during access opening with the Er: YAG laser.
authors.affiliation: 1 Department of Stomatology, Nanshan Affiliated Hospital of Guangdong Medical College , Shenzhen, Guangdong, China .
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Ding
authors.forename: Arata
authors.initials: A
authors.lastname: Ebihara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Iino
authors.forename: Chizuko
authors.initials: C
authors.lastname: Kokuzawa
authors.forename: Tomoo
authors.initials: T
authors.lastname: Anjo
authors.forename: Hideaki
authors.initials: H
authors.lastname: Suda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sumi
mesh_terms: D003737:Dental Cavity Preparation / Q000379:methods*; D003789:Dental Pulp Exposure / Q000175:diagnosis*; D006801:Humans; D007180:Incisor; D053844:Lasers, Solid-State; D018915:Root Canal Preparation; D041623:Tomography, Optical Coherence