Quantitative analysis of tooth wear in-vivo using 3D scanning technology

RK Dentistry

Ahmed, Khaled ; Whitters, C. John

University:University of Glasgow

Department:School of Medicine, Dentistry & Nursing

关键词: Tooth wear, attrition, erosion, 3D scanning, CAD, CAM, impression materials, dental stone, tooth surface loss;   

Others  :  http://theses.gla.ac.uk/5148/7/2014AhmedPhD.pdf

来源: University of Glasgow

【 摘 要 】

Aim: The primary aim of this study was to develop,calibrate and assess a novel methodology that employs 3D scanning technology in quantifying the progression of tooth wear and then assess the applicability and validity of this methodology in-vivo through clinical monitoring of the progression of tooth wear in patients over a period of 12 months.Methods and materials: A Stainless Steel Model (SSM) was fabricated consisting of seven stainless-steel ball-bearings embedded in a horseshoe-shaped base. The dimensions of the SSM were ascertained using a Coordinate Measuring Machine (CMM). The CMM calibrated SSM was used to identify the accuracy and precision of a contact stylus profilometer scanner and a non-contact class-II laser arm-scanner. The next stage involved using the SSM to identify the initial dimensional accuracy of Type IV dental stone casts poured from impressions of the SSM, using 3 types of impression materials: alginates (Alg), polyethers (PE) and polyvinylsiloxanes (PVS), and the dimensional stability of the dental stone over a period of one-month. Thereafter, the overall 3D scanning system performance was calculated. A clinical study involving tooth wear patients, recruited through 3 Restorative Dentistry Consultants’ New Patient clinics, was also carried-out. At initial visit and after 1 year, PE impressions were taken of participants’ dentition and poured. At 1 month post-pouring, the casts were 3D-scanned. The resultant scans of initial visit casts and after 1 year casts were 3D analysed, compared and differences detected.Results: The contact scanner demonstrated greater accuracy and precision compared to the non-contact scanner. Alg-fabricated casts demonstrated the largest discrepancy, producing undersized casts. PVS was the most accurate but concurrently demonstrated greater statistical variance compared to PE. The overall 3D scanning system performance, when comparing 2 individual contact scans taken of Type IV stone casts poured from PE impressions then scanned at one-month post-pouring, was 66μm. Clinically, allparticipants in this study presented with tooth wear greater than 140μm in depth; however, detected tooth wear only affected a limited surface area of anterior teeth.Conclusion: In this pilot study, we were able to formulate a novel descriptive 3D scanning methodology for quantifying tooth wear that accounts for the various factors affecting 3D scanning in-vivo. We have also demonstrated the clinical applicability of the methodology in monitoring the rate of tooth wear progression in patients.