title: Non-destructive 3D imaging of composite restorations using optical coherence tomography: marginal adaptation of self-etch adhesives.
abstract: OBJECTIVE
  To investigate the potential use of swept-source optical coherence tomography (SS-OCT) as a new tool to evaluate marginal adaptation of composite restorations in class I cavities.
  
  
  METHODS
  Round-shaped class I cavities (3mm diameter × 1.5mm depth) were prepared on buccal enamel of bovine teeth with cavity floor located in dentine. The cavities were restored with a flowable resin composite (Clearfil Majesty LV) using two-step self-etch adhesive (SE Bond), all-in-one self-etch adhesive (G-Bond) or no adhesive (Control). The specimens were subjected to water storage (37 °C, 24 h) or thermal stress challenge (5000 cycles, 5 °C and 55 °C). 3D scans (4 mm×4 mm×2.6 mm obtained in 4 s) of the restoration were obtained using SS-OCT before and after immersion into a contrast agent. 2D images obtained from the 3D scans (n=30/group) were analysed to evaluate marginal adaptation. Area fraction of pixels with high brightness values at the interfacial zone was calculated using a digital image analysis software. The results were statistically compared with statistical significance defined as p≤0.05.
  
  
  RESULTS
  Wilcoxon signed ranks test showed that there was no statistically significant difference in the results of SS-OCT before and after infiltration of the contrast agent when a ranking transformation was applied on to the data (p>0.05). A significant positive linear correlation was found between the two SS-OCT images. Confocal laser scanning photomicrographs of samples cut after silver infiltration confirmed the presence of gap.
  
  
  CONCLUSIONS
  3D imaging by SS-OCT can be considered as a non-invasive technique for fast detection of gaps at the restoration interface.
authors.affiliation: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. pmakishi@gmail.com
authors.forename: Patricia
authors.initials: P
authors.lastname: Makishi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shimada
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sumi
mesh_terms: D000269:Adhesives; D000818:Animals; D002417:Cattle; D003188:Composite Resins; D003287:Contrast Media; D003737:Dental Cavity Preparation / Q000145:classification; D045662:Dental Etching / Q000379:methods; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008689:Methacrylates; D018613:Microscopy, Confocal; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D012834:Silver; D012835:Silver Nitrate; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D000269:Adhesives; C438313:Clearfil SE Bond; D003188:Composite Resins; D003287:Contrast Media; C498353:G-Bond; D008689:Methacrylates; D019279:Resin Cements; C000212:ammoniacal silver; D012834:Silver; D012835:Silver Nitrate