Travis Moore

Date of Graduation

2018

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Not Listed

Committee Chair

Peter Ngan

Committee Co-Chair

Bryan Weaver

Committee Member

L. Keith Hildebrand

Committee Member

M. Leigh Speer

Abstract

Introduction Access cavity design is known to affect theefficiency of instrumentation. Canal transportation occurs primarily in the apical region and to the outside of curvature when dentin is removed in a single direction. The goal of all cleaning and shaping procedures is to preserve the original root canal anatomy while removing sufficient amounts of injured pulp tissue, microorganisms, toxins and instrumentation byproducts. It is understood that the desired shape of the finished root canal is a continuous tapering funnel from the coronal to the apex. The aim of this study is to construct detailed three-dimensional images of root canal systems and measure the change in canal anatomy based on varying the access cavity designs, using WaveOne Gold®(WOG) and ProTaper NEXT®(PTN) files. Materials and Methods All teeth used were 3D printed maxillary first molar teeth purchased from Dental Education Laboratories. One unaltered tooth was scanned with a SkyScan 1272 microCT to be used as the control when gathering pre-instrumentation measurements of root thickness. Images were transferred to corresponding Bruker imaging software platforms to evaluate the pre-instrumentation root thickness of the mesial buccal at 1.0, 3.0, 5.0mm’s from the apex. Access stents for traditional and contracted access were then created using a microCT scan and 3D printer based on previously accessed molar teeth with traditional and contracted endodontic access. One hundred teeth were evenly divided into file and access combination groups A)WOG/Traditional access B)WOG/Contracted access C)PTN/Traditional access and D)PTN/Contracted access. Each tooth was then imaged and measured for root thickness of the mesial buccal at 1.0, 3.0, 5.0mm’s from the apex manor identical to the pre-instrumentation measurement. After data collection a two-way ANOVA was carried out to assess how drill, access, and the interaction between drill and access affect canal transportation and centering ratio. Since canal transport at 3.0 and 5.0mm’s have significant interaction p-values a Tukey HSD was done to see where the difference lies. Results For canal transport at 1 mm from the root apex, contracted access design demonstrated higher canal transport than the traditional access type regardless of the file tested. At depths of 3mm and 5mm, the traditional access type has a higher centering ratio than the contracted access type regardless of file iii utilized. At a depth of 5mm, the PTN file has a higher centering ratio than the WOG file regardless of access type. Conclusion The current study did not show benefits for contracted endodontic cavity using either a continuously rotating or reciprocating file in the mesial buccal root of maxillary first molars. This access modality resulted in greater canal transportation at 1mm, 3mm and 5mm from the apex. The ProTaper NEXT® file resulted in less canal transportation than WaveOne Gold® in all scenarios evaluated. However, the difference is only statistically significant at 3.0 and 5.0mm’s from the apex when WaveOne Gold® used with a contracted endodontic access. The greatest amount of canal transportation was seen with a combination of WaveOne Gold® and contracted access while the least amount of canal transportation was seen with a combination of ProTaper NEXT® and a traditional endodontic cavity. This difference was statistically significant.

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