Characterization of dental interfaces with electron tomography Kathryn Grandfield and Håkan Engqvist Citation: Biointerphases 9, 029001 (2014); doi: 10.1116/1.4862096 View online: http://dx.doi.org/10.1116/1.4862096 View Table of Contents: http://scitation.aip.org/content/avs/journal/bip/9/2?ver=pdfcov Published by the AVS: Science & Technology of Materials, Interfaces, and Processing Articles you may be interested in Metal artifact correction for x-ray computed tomography using kV and selective MV imaging Med. Phys. 41, 121910 (2014); 10.1118/1.4901551 A quality assurance framework for the fully automated and objective evaluation of image quality in cone-beam computed tomography Med. Phys. 41, 031901 (2014); 10.1118/1.4863507 Transrectal electrical impedance tomography of the prostate: Spatially coregistered pathological findings for prostate cancer detection Med. Phys. 40, 063102 (2013); 10.1118/1.4803498 A study of matching fluid loss in a biomedical microwave tomography system Med. Phys. 40, 023101 (2013); 10.1118/1.4788640 Reduction of dental filling metallic artifacts in CT-based attenuation correction of PET data using weighted virtual sinograms optimized by a genetic algorithm Med. Phys. 37, 6166 (2010); 10.1118/1.3511507
Characterization of dental interfaces with electron tomography Kathryn Grandfielda) Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
Ha˚kan Engqvist Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden
(Received 27 November 2013; accepted 23 December 2013; published 21 January 2014) Understanding the interface between dental materials and tooth is critical in the prevention of secondary caries. Assessing this interface with high-resolution clarity has traditionally been challenging. This work highlights electron tomography, carried out in the transmission electron microscope, as a novel technique to obtain both three-dimensional and nanometer scaled information on dental materials in contact with dentin. In this study, commercial calcium aluminate and glass ionomer based luting agents in contact with human dentin were prepared for electron microscopy via focused ion beam milling. Imaging with high-angle annular dark field provided compositional contrast, and combined with tilting over large angular ranges, enabled the reconstruction of the three-dimensional interface between tissue and cement. The characteristics of the interface were observed with this extra dimensionality and superior resolution, providing C 2014 evidence for the viability of this technique in interfacial studies of dental materials. V American Vacuum Society. [http://dx.doi.org/10.1116/1.4862096]
I. INTRODUCTION A variety of materials are used in preventative and restorative dental sciences to restore function to patients, making the analysis of these material interfaces with each other and natural tissues a key concern. In the case of luting agents used for the placement of oral prosthetic devices, a primary concern is the risk of formation of secondary caries. Secondary caries occur as a result of leakage at the interface between the restorative material and tooth, where bacteria and nutrients infiltrate.1 Thus, the sealing ability of dental materials is of great interest for permanent restorations of the teeth. At the most fundamental level, the integrity of the seal between dental materials and natural tissue originates at the ultrastructural level. However, techniques to analyze the interface of dental materials with suitable resolution are limited. Investigations with light and x-ray based techniques are insufficient. Electron microscopy, on the other hand, provides the ability to analyze interfaces with nanometer resolution. Recently, electron tomography has presented itself as a promising technique for the study of biointerfaces including bone tissue interfacing to a variety of implant materials including hydroxyapatite,2 commercially pure titanium,3 and titanium alloys.4 This paper aims to evaluate the technique of electron tomography for applications in analyzing dental material interfaces with high resolution and three-dimensional clarity. This is demonstrated by the tomographic reconstruction of R the commercial luting agents Ceramir Crown and BridgeV
(Doxa Dental AB, Sweden) and Fuji I (GC Europe, Belgium) in contact with human dentin. II. METHODS Commercially available luting agents, Ceramir Crown & Bridge (Doxa Dental AB, Sweden) and Fuji I (GC Europe, Belgium), were used to cement a zirconia crown to extracted teeth, according to manufacturer’s guidelines. Samples were sectioned longitudinally with a slow-speed saw to reveal the dentin–cement and zirconia–cement interface in crosssection. Scanning electron microscopy (SEM) backscattered electron micrographs were recorded to provide an overview of the interface regions. An in situ lift-out focused ion beam (FIB) technique on a Zeiss NVision 40 dual-beam FIB (Carl Zeiss AG, Germany) equipped with a 30 kV gallium ion column, field emission gun SEM, carbon gas injector system, and Kleindiek probe drive system (Kleindiek Nanotechnik GmbH, Germany) was used to select and create thin lamellae (
Characterization of dental interfaces with electron tomography Kathryn Grandfielda) Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
Ha˚kan Engqvist Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden
(Received 27 November 2013; accepted 23 December 2013; published 21 January 2014) Understanding the interface between dental materials and tooth is critical in the prevention of secondary caries. Assessing this interface with high-resolution clarity has traditionally been challenging. This work highlights electron tomography, carried out in the transmission electron microscope, as a novel technique to obtain both three-dimensional and nanometer scaled information on dental materials in contact with dentin. In this study, commercial calcium aluminate and glass ionomer based luting agents in contact with human dentin were prepared for electron microscopy via focused ion beam milling. Imaging with high-angle annular dark field provided compositional contrast, and combined with tilting over large angular ranges, enabled the reconstruction of the three-dimensional interface between tissue and cement. The characteristics of the interface were observed with this extra dimensionality and superior resolution, providing C 2014 evidence for the viability of this technique in interfacial studies of dental materials. V American Vacuum Society. [http://dx.doi.org/10.1116/1.4862096]
I. INTRODUCTION A variety of materials are used in preventative and restorative dental sciences to restore function to patients, making the analysis of these material interfaces with each other and natural tissues a key concern. In the case of luting agents used for the placement of oral prosthetic devices, a primary concern is the risk of formation of secondary caries. Secondary caries occur as a result of leakage at the interface between the restorative material and tooth, where bacteria and nutrients infiltrate.1 Thus, the sealing ability of dental materials is of great interest for permanent restorations of the teeth. At the most fundamental level, the integrity of the seal between dental materials and natural tissue originates at the ultrastructural level. However, techniques to analyze the interface of dental materials with suitable resolution are limited. Investigations with light and x-ray based techniques are insufficient. Electron microscopy, on the other hand, provides the ability to analyze interfaces with nanometer resolution. Recently, electron tomography has presented itself as a promising technique for the study of biointerfaces including bone tissue interfacing to a variety of implant materials including hydroxyapatite,2 commercially pure titanium,3 and titanium alloys.4 This paper aims to evaluate the technique of electron tomography for applications in analyzing dental material interfaces with high resolution and three-dimensional clarity. This is demonstrated by the tomographic reconstruction of R the commercial luting agents Ceramir Crown and BridgeV
(Doxa Dental AB, Sweden) and Fuji I (GC Europe, Belgium) in contact with human dentin. II. METHODS Commercially available luting agents, Ceramir Crown & Bridge (Doxa Dental AB, Sweden) and Fuji I (GC Europe, Belgium), were used to cement a zirconia crown to extracted teeth, according to manufacturer’s guidelines. Samples were sectioned longitudinally with a slow-speed saw to reveal the dentin–cement and zirconia–cement interface in crosssection. Scanning electron microscopy (SEM) backscattered electron micrographs were recorded to provide an overview of the interface regions. An in situ lift-out focused ion beam (FIB) technique on a Zeiss NVision 40 dual-beam FIB (Carl Zeiss AG, Germany) equipped with a 30 kV gallium ion column, field emission gun SEM, carbon gas injector system, and Kleindiek probe drive system (Kleindiek Nanotechnik GmbH, Germany) was used to select and create thin lamellae (
