Jeffrey Martin Coil

Assistant Professor

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Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Analgesic and Antibiotic Prescribing Decisions of British Columbian Dentists and Endodontists (2015)

The problems associated with a global increase in antibiotic use and prescription opioid abuse have been well documented. The aim of this study was to assess the prescribing decisions of general dentists and endodontists in British Columbia regarding analgesics and antibiotics in clinical scenarios that involve endodontic disease. An additional aim was to determine whether gender, clinical experience, or the practice location of the clinician impacted their decision-making. A four-page survey was developed and distributed to half of the general dentists in Vancouver, British Columbia (n=284) and all of the endodontists in British Columbia (n=51). The survey began with some basic demographical questions, continued with seven different clinical scenarios, and concluded with a table that listed a number of different endodontic diagnoses. The participants were asked questions regarding their decisions to recommend or prescribe analgesics or antibiotics. The response rate to the survey was 49.2%. 72.0% of endodontists responded, as compared to 44.8% of general dentists. A substantial proportion of clinicians prescribed opioid analgesics and antibiotics in the various clinical scenarios. The prescription of opioid analgesics ranged from 3.6% - 46.8% over the various scenarios. The prescription of antibiotics ranged from 4.8% - 88.4%. General dentists reported prescribing opioid analgesics and antibiotics more often than endodontists. However, the respondents to our survey prescribed antibiotics less frequently than those of a 1996 survey conducted in the USA. Gender, clinical experience, and practice location did not seem to impact the decision to prescribe opioid analgesics or antibiotics.

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Micro-Computed Tomography Analysis of Post Space Preparation in Teeth Obturated With Carrier-Based Thermoplasticized Gutta Percha Techniques (2015)

Many dentists use the obturation technique of carrier-based thermoplasticized gutta percha. Placement of a post may be indicated for teeth in which there has been extensive loss of coronal tooth structure. This study aimed to determine if post space preparation deviated from the endodontic preparation in teeth obturated with the Thermafil, GuttaCore, or gutta percha material. Forty-two extracted human permanent maxillary lateral incisors were decoronated and their root canals instrumented with nickel-titanium rotary files using a standardized protocol. Samples were divided into three groups and filled with Thermafil, GuttaCore, or gutta percha, before post space preparation was performed. Teeth were scanned using micro-computed tomography after obturation, and again after post space preparation. Scans were examined for post space deviation, volume and linear deviation of post space preparation, and minimum root thickness before and after post space preparation. Data were analyzed with parametric and non-parametric statistical methods. Deviation occurred in eight teeth; seven from the Thermafil group (50%), one from the GuttaCore group (7%), and none from the gutta percha group. Deviation occurred statistically more often in the Thermafil group than in each of the other two groups (p
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In vitro comparison of retrieval efficiency and capacity for three endodontic obturation materials (2013)

GuttaCore® is advertised as rendering high-quality carrier-based obturation and being retreatable with unprecedented ease. This study’s aim was to evaluate time required for ProTaper®Retreatment files to remove three obturation materials in mesio-buccal (MB) canals and distal (D) canals of lower molars, and quantify residual material left on canal walls following retreatment.MB and D canals of first and second lower molars were standardized according to type, length, curvature and quadrant, and divided into three obturation groups (NMB=15; ND=12). MB canals were instrumented to 25/.08 (ProTaper®Universal F2) and D to 30/.09 (ProTaper®Universal F3). Canals were obturated with vertically compacted gutta-percha cones (GP), Thermafil®Plus (T) or GuttaCore® (GC). Teeth were stored for two weeks allowing sealer setting. Retreatment time to reach working length with ProTaper®Universal Retreatment files (D1, D2, D3) and with last ProTaper®Universal file used during original instrumentation was recorded in seconds. Roots were then sectioned longitudinally, visualized using 8.0x magnification, and residual gutta-percha along canals was quantified using a five-point grading system.A statistical significant difference in retreatment time between GC group and T group in MB canals was found (P = 0.026). No statistical significant difference in retreatment time was detected amongst the materials (P > 0.05). No statistical significant difference was found in residual obturation material between groups both in MB and D canals. GC group is more efficient to remove than T group in MB canals. No difference was found in the obturation removal amongst the three groups in the wider D canals. All groups exhibited residual gutta-percha along canal walls; further instrumentation is needed for thorough material removal.

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Evaluation of canal instrumentation using GT-series-Xtm versus Prosystem GTtm (2011)

Preparation of the root canal system is recognized as being one of the most important stages in root canal treatment. A variety of instrumentation techniques have been described for this stage of root canal treatment. Two recently introduced rotary instrument systems are ProSystem GT™ and GT-Series-X™. The aim of this study is to compare the ability of two nickel- titanium rotary file systems, GT-Series-X™, and ProSystem GT™, to maintain the original canal path using a split-mold design (the endodontic cube). The hypothesis is that ProSystem GT™ will create greater canal center displacement in comparison with GT-Series-X™ files due to more chip spaces and fewer cutting flutes in the latter.Methods: Mesial roots of 31 mandibular first and second molar teeth with separate ML and MB canals and curvatures ranging from 15 to 40 degrees were randomly divided into two groups. After access cavity preparation and working length determination, each tooth was embedded in composite resin using the endodontic cube as a mold. 1.5mm tooth-resin complex slices were made using a Buehler ™ slow speed saw. After reassembly of the sections, canals were instrumented with either GT-Series-X™ or ProSystem GT™ to size 30/06. AutoCAD™ software was used to measure root section images of instrumented canals. Data was analyzed using the t-test (p
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