Biomaterial Database

Quantification of residual dentine thickness following crown preparation. 2012

Graham R Davis, and Rabab A Tayeb, and Kevin G Seymour, and George P Cherukara

Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Turner Street, London E1 2AD, United Kingdom. G.R.Davis@qmul.ac.uk

OBJECTIVE Pulpal response to tooth preparation is a major concern in fixed prosthodontics. Research has suggested that 2mm or more of remaining dentine is critical in protecting the pulp following tooth preparation. However, clinicians have no means of knowing dentine thickness either before or after preparation and therefore lack feedback about this important aspect of preparation quality. The aim of this project was to develop a method for measuring local dentine thickness following tooth preparation for metal ceramic crowns, in vitro, which could be used as a tool to evaluate preparation technique and instrumentation. METHODS Microtomography (XMT or micro-CT) scans were taken of extracted teeth before and after crown preparation. Local dentine thickness was defined for every voxel within the 3D tooth image as the sum of distances from that voxel to the pulp and to the anatomical surface. The method also allows the thickness of material removed to be quantified. Three-dimensional colour-coded maps of dentine thickness were generated, and the distributions of dentine thickness throughout the teeth were analysed. This was tested by a single operator on sixteen extracted upper central incisors. RESULTS This method enabled clear visualisation and analysis of residual dentine thickness. In the trial, it revealed consistent over-prepared regions along the labial proximal line angles which, in a clinical case, could affect subsequent tooth and restoration longevity. All but one of the prepared teeth had regions with a residual dentine thickness of less than 1.5mm, in 6 it was less than 1.0mm and in 3 of these it was less than 0.5mm. CONCLUSIONS Although ex vivo, this method can be used as a research tool to look for patterns of over- or under-preparation, leading to possible modification of technique, instrumentation and, or crown design. CONCLUSIONS It is not currently possible for clinicians to know the thickness of residual dentine following crown preparation, a key factor in long term outcome. The described method of quantifying and visualising this thickness allows preparation techniques and instrumentation to be evaluated in vitro, leading to prospective improvements in clinical procedures.

UI	MeSH Term	Description	Entries
D007091	Image Processing, Computer-Assisted	A technique of inputting two-dimensional or three-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.	Biomedical Image Processing,Computer-Assisted Image Processing,Digital Image Processing,Image Analysis, Computer-Assisted,Image Reconstruction,Medical Image Processing,Analysis, Computer-Assisted Image,Computer-Assisted Image Analysis,Computer Assisted Image Analysis,Computer Assisted Image Processing,Computer-Assisted Image Analyses,Image Analyses, Computer-Assisted,Image Analysis, Computer Assisted,Image Processing, Biomedical,Image Processing, Computer Assisted,Image Processing, Digital,Image Processing, Medical,Image Processings, Medical,Image Reconstructions,Medical Image Processings,Processing, Biomedical Image,Processing, Digital Image,Processing, Medical Image,Processings, Digital Image,Processings, Medical Image,Reconstruction, Image,Reconstructions, Image
D007180	Incisor	Any of the eight frontal teeth (four maxillary and four mandibular) having a sharp incisal edge for cutting food and a single root, which occurs in man both as a deciduous and a permanent tooth. (Jablonski, Dictionary of Dentistry, 1992, p820)	Incisors
D008422	Materials Testing	The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.	Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D003442	Crowns	A prosthetic restoration that reproduces the entire surface anatomy of the visible natural crown of a tooth. It may be partial (covering three or more surfaces of a tooth) or complete (covering all surfaces). It is made of gold or other metal, porcelain, or resin.	Dental Crowns,Crown, Dental,Crowns, Dental,Dental Crown,Crown
D003782	Dental Pulp	A richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (Jablonski, Dictionary of Dentistry, 1992)	Dental Pulps,Pulp, Dental,Pulps, Dental
D003804	Dentin	The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)	Dentine,Dentines,Dentins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D017267	Dental Prosthesis Design	The plan and delineation of dental prostheses in general or a specific dental prosthesis. It does not include DENTURE DESIGN. The framework usually consists of metal.	Dental Prosthesis Designs,Design, Dental Prosthesis,Designs, Dental Prosthesis,Prosthesis Design, Dental,Prosthesis Designs, Dental
D055114	X-Ray Microtomography	X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.	MicroCT,Microcomputed Tomography,X-Ray Micro-CAT Scans,X-Ray Micro-CT,X-Ray Micro-CT Scans,X-Ray Micro-Computed Tomography,X-Ray Microcomputed Tomography,X-ray MicroCT,Xray Micro-CT,Xray MicroCT,Micro-CAT Scan, X-Ray,Micro-CAT Scans, X-Ray,Micro-CT Scan, X-Ray,Micro-CT Scans, X-Ray,Micro-CT, X-Ray,Micro-CT, Xray,Micro-CTs, X-Ray,Micro-CTs, Xray,Micro-Computed Tomography, X-Ray,MicroCT, X-ray,MicroCT, Xray,MicroCTs,MicroCTs, X-ray,MicroCTs, Xray,Microcomputed Tomography, X-Ray,Microtomography, X-Ray,Scan, X-Ray Micro-CAT,Scan, X-Ray Micro-CT,Scans, X-Ray Micro-CAT,Scans, X-Ray Micro-CT,Tomography, Microcomputed,Tomography, X-Ray Micro-Computed,Tomography, X-Ray Microcomputed,X Ray Micro CAT Scans,X Ray Micro CT,X Ray Micro CT Scans,X Ray Micro Computed Tomography,X Ray Microcomputed Tomography,X Ray Microtomography,X ray MicroCT,X-Ray Micro-CAT Scan,X-Ray Micro-CT Scan,X-Ray Micro-CTs,X-ray MicroCTs,Xray Micro CT,Xray Micro-CTs,Xray MicroCTs
D019231	Tooth Preparation, Prosthodontic	The selected form given to a natural tooth when it is reduced by instrumentation to receive a prosthesis (e.g., artificial crown or a retainer for a fixed or removable prosthesis). The selection of the form is guided by clinical circumstances and physical properties of the materials that make up the prosthesis. (Boucher's Clinical Dental Terminology, 4th ed, p239)	Preparation, Prosthodontic Tooth,Preparations, Prosthodontic Tooth,Prosthodontic Tooth Preparation,Prosthodontic Tooth Preparations,Tooth Preparations, Prosthodontic