Sakhaei Manesh, Vahid (2017) Quantitative assessment of covariants of root canal treatment efficacy in human teeth. PhD thesis, James Cook University.

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Abstract

Clinically relevant cofactors that can demonstrate aspects of root canal treatment quality are of importance to clinicians, researchers and dental instrument manufacturers. Endodontics has been one of the most developing fields of dental science in recent years. There have been new instruments, materials, and methods introduced, which have been very rapidly adopted since most facilitate the root canal treatment process. Considering the current rate of technological developments and the long-term follow-ups required for clinical evaluation of root canal treatment success, clinical trials are not feasible for assessing every variable in treatment. In search of cofactors that could be used to demonstrate the efficacy and quality of a root canal treatment, the effect of surface roughness was investigated in the present thesis.

Clinical relevance of surface roughness and its effect on endodontic treatments was assessed in the second chapter. This aim was achieved by comparing biofilm formation on rough and smooth dentine surfaces. Enterococcus faecalis was the microorganism tested to form biofilms on these surfaces because of its role as one of the most important endodontic pathogens in persistent endodontic infections. A novel methodology utilizing flow cytometry to quantify bacteria attached to the surfaces was designed for this experiment. The results showed that rough surfaces harboured a significantly higher number of bacteria compared to smooth surfaces. This indicated that achieving a final smooth surface in root canal treatment reduces the chance of bacterial biofilm formation. Considering the wide range of instrument designs and functions that are used in endodontic treatments, the results demonstrated the necessity for further investigations into their effect on a treated canal's final surface quality.

Practical aspects of root canal treatment that may be effective on the canal surface roughness were the focus of the next experiments of this thesis. The third chapter compares the effect of two different filing motions, continuous rotary and adaptive reciprocation, on root canal surface roughness. Continuous rotation and reciprocation are the two most frequently used filing techniques in root canal instrumentation. In this experiment, a filing system that was compatible to work in both rotary and adaptive reciprocation modes was used to answer whether filing motion can affect surface roughness of a root canal. Experiments showed that surface roughness was significantly higher overall in the root canals of teeth prepared with adaptive reciprocation compared to continuous rotary. The results of this chapter showed that roughness of the root canal is a cofactor that can be modified by the clinician. Treatment strategies with different techniques can be implemented even while using identical instruments to achieve smoother treated surfaces. Based on the findings of this study, using a continuous rotary system to prepare canals or to finish the cleaning and shaping stage of a root canal treatment can be beneficial to reducing roughness of the canal surface.

Differences between filing systems consists of differences in a mixture of variables including alloy, surface treatment, cross-section, taper, motion, design, etc. The fourth chapter in this series was aimed to evaluate the effect of three different filing systems with different concepts, on the final root canal surface quality. Cleaning and shaping was carried out on teeth with either a single-file reciprocating (Reciproc), continuous rotary (HyFlex EDM) or oscillating self-adjusting file (SAF) system. The results from this chapter showed that the three completely different filing systems resulted in similarly rough root canal surfaces. The high level of roughness in all groups suggested that the three filing systems tested in this experiment were relatively aggressive.

File wear results in reduced cutting efficiency and aggressiveness. Since each file undergoes a life cycle and it is eventually worn out, the fifth chapter of this thesis was designed to assess how the effect of file wear translates into changes on the treated root canal surface roughness. In order to evaluate the impact of file wear effectively, Reciproc single-file reciprocating instruments were used for this study. Reciproc files endure the same stress that is usually distributed among a number of files in multi-file systems. This study showed that the amount of wear during three uses, which is within the range of use recommended by the manufacturer, does not affect the final root canal surface roughness. Without consideration of safety of these files in terms of file separation risk, these files can be used up to three times while expecting a similar treatment outcome. However, similar to the previous study, these files left a relatively rough surface in all cases.

The key findings in the present thesis were that root canal surface roughness is an effective and modifiable cofactor that can be used to determine the quality of root canal instrumentation and the performance of the instruments used. The two new methodologies developed can be used to test other available endodontic instruments and techniques. These methods can provide a foundation for generating comparable and quantitative data regarding the roughness values and thresholds associated with biofilm formation and different endodontic instruments. Standard levels can be set for future instrument designs once enough research is available regarding the performance of the current instruments and the ideal levels of surface roughness.

Item ID:	56209
Item Type:	Thesis (PhD)
Keywords:	root canal preparation, scanning electron microscopy, surface roughness
Related URLs:	https://researchonline.jcu.edu.au/50474/
Copyright Information:	Copyright © 2017 Vahid Sakhaei Manesh
Additional Information:	Publications arising from this thesis are available from the Related URLs field. The publications are: Chapter 3: Sakhaei Manesh, Vahid, Giacomin, Paul, and Stoll, Richard (2017) Quantitative evaluation of root canal surface roughness after filing with adaptive reciprocating and continuous rotary instruments. Microscopy Research and Technique, 80 (6). pp. 657-661.
Date Deposited:	26 Nov 2018 22:33
FoR Codes:	11 MEDICAL AND HEALTH SCIENCES > 1105 Dentistry > 110503 Endodontics @ 50% 11 MEDICAL AND HEALTH SCIENCES > 1105 Dentistry > 110501 Dental Materials and Equipment @ 50%
SEO Codes:	92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920118 Surgical Methods and Procedures @ 100%
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