AbstractTHE PLACEMENT OF MINERAL TRIOXIDE AGGREGATE USING TWO DIFFERENT TECHNIQUESBy Anita Aminoshariae, D.D.S.A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth UniversityVirginia Commonwealth University, 2003Major Director: Gary R. Hartwell, D.D.S., M.S.Chairman and Professor, Department of EndodonticsThe purpose of this study was to determine if the adaptation of Mineral Trioxide Aggregate (MTA) to the walls of the samples would differ when placed into simulated root canals of varying length using two different placement and condensation methods. Hand condensation was compared to ultrasonic condensation. Eighty polyethylene tubes were divided into four groups of twenty tubes each. The tubes in the four groups were prepared to receive 3, 5, 7 and 10-mm lengths of MTA respectively. Each group of twenty tubes was then subdivided so that ten samples of each length would have MTA placed and condensed by the hand method and the other ten by the ultrasonic method. After condensation the samples were evaluated with a light microscope and radiographs for the degree of adaptation of the MTA to the tube walls and for the presence of voids within the MTA material itself. The results demonstrated an 80% agreement for findings between the light microscopy and radiographic evaluation. Hand condensation resulted in better adaptation to the tube walls and less voids than the ultrasonic method. There was no significant difference in the results for any of the four lengths of MTA placed by the hand method (p> 0.9). At this time hand condensation should be considered the preferred method for placement of MTA.

The purpose of this study was evaluate the interobserver reliability of endodontists in the diagnosis the presence or absence of pulpal and/or periradicular disease. The study used 47 patients presenting to the VCU School of Dentistry for screening appointments as a test population under the rules and regulations of the VCU IRB. The patients were examined separately by two endodontists, using a thorough patient history, clinical exam, and radiographs. The answer to the question was then answered, does the patient have pulpal and/or periradicular disease, and compared. The data was analyzed using Kappa and the standard error was determined to test for statistical significance. Observers agreed 88% of the time with a Kappa of 0.74. This was determined to represent a bona fide reliability with p<.0001. The results indicate that agreement among endodontists is very good when patients are evaluated for pulpal and/or periradicular disease.

The purpose of this study was to determine the prevalence and demographic predictors of pulpal and/or periradicular disease in an urban population. A total of 210 subjects were recruited from a population of patients that were screened for acceptance to the dental school clinics. The diagnosis of pulpal and/or periradicular disease was made using the following data: radiographic interpretation, patient's history of previous pain and chief complaint, and objective pulpal testing. Objective pulpal testing included percussion, palpation, electric pulp test, and cold. The unit of observation was the individual, not the tooth. The overall prevalence of endodontic disease among the study sample of the screening patient population was 39.52%. Controlling for gender, patients in the 30-39 age group were 3.05 times more likely to have pulpal disease than patients in the 18-29 age group (OR=3.05, 95%CI 1.04-8.9). Controlling for age, men were 1.82 times more likely to have pulpal disease than women (OR=1.82, 95%CI 1.01-3.26). Non-white patients were 2.69 times more likely to have pulpal disease than white patients (OR=2.69, 95%CI 1.51-4.81). Patients who earned less than $25,000 were 2.06 times more likely to have pulpal disease compared to those who earned more than $25,000 (OR=2.06, 95% CI 1.15-3.69). Overall, this data provides valuable information for identifying vulnerable populations and addressing the policy goals of the U.S. Surgeon General.

The purpose of this study was to examine the number of rotations to failure of two different rotary file systems, EndoSquence Brassler USA (Savannah, GA) and GT(TM) series X(TM). Files sizes 20,30,40 with 0.04, 0.06 tapers of GT series X and Endo Sequence files size and taper used were 20, 30, 40 with 0.04 and 0.06 taper. Like tip and tapers were compared between systems. All files tested were 25mm in length. Files were allocated into 12 groups of 10 files each, and mounted to a universal testing machine. Each file was rotated at 300 rpms until fractured occurred. The number of rotations to fracture were calculated. A two-way ANOVA indicated that each of the 12 groups were significantly different (p < .0001). The Brand Tip/Taper interaction indicated that the differences between the brands varied by Tip/Taper combination (p < .0001). The tip/taper combination 20/.04, the GT series X file rotated 1.4 times longer than the EndoSequence (p = 0.0027). The tip/taper combination 20/.06, the GT series X file rotated 1.61 times longer than the EndoSequence (p = <.0001). The tip/taper combination 30/.04, the GT series X file rotated 3.67 times longer, than the EndoSequence (p = <.0001). For the tip/taper combination 30/.06, the GT series X file rotated 2.63 times longer than the EndoSequence (p = <.0001). For the tip/taper combination 40/.06, the GT series X file rotated 4.05 times longer than the EndoSequence (p = <.0001). In comparing all these tip and taper combinations GT series X was significantly higher rotations to failure. Comparing tip/taper combination 40/.04, the GT series X file rotated 1.22 times longer, however, this was not significantly different than the Sequence (p = 0.0707). The results suggested that the number of rotations to failure for GT series X files were greater than the EndoSequence file of the same tip and taper combination.

The purpose of this study was to compare the resistance to fracture by the twisting of two nickel titanium (NiTi) rotary file systems. The Profile® GT® (GT) and the GT® Series X(TM) (GTX) files were tested to analyze the maximum torsional strength and the maximum angular deflection at the time of separation of the files. For each system, ten new files were tested at each of the following eight taper/size designations for a total of 160 files: 20/0.04, 20/0.06, 30/0.04, 30/0.06, 30/0.08, 40/0.04, 40/0.06, and 40/0.08. The American National Standards Institute / American Dental Association Specification No. 28 was implemented to evaluate torsional limits for these intruments. Files were mounted in a Maillefer Torsiometre machine, which records maximum torsional strength and angular deflection at separation for each file. A two-way ANOVA revealed significant differences after comparing the size and type of file. The GT files required significantly more torque to separate than the GTX files in all groups tested except the GTX file size 20/0.06, which required significantly more maximum torque than the GT file, with no significant difference between the GT and GTX files for size 30/0.04. The GT files exhibited values for angular deflection at separation that were significantly higher than those for the GTX files at sizes 30/0.04 and 40/0.08 and the GTX files exhibited higher values at size 30/0.08 with no significant difference between the brands at the remaining five file sizes. In summary, the GT files required significantly more torque to fracture and exhibited values for angular deflection at separation that were significantly higher than the GTX files for in 6 of 8 and 2 of 8 file sizes, respectively.

Endodontic residents must keep current with clinical information to practice evidence- based dentistry. To do so, endodontic residents must access research papers and interpret results. This requires a knowledge of biostatistics. However, the biostatistical knowledge of endodontic residents is relatively unknown. The purpose of the study was to assess the biostatistical knowledge of endodontic residents using a survey instrument to prove or reject the hypothesis that there exists a lack of understanding of biostatistic principles among endodontic residents. A survey consisting of 29 questions querying attitudes and biostatistical knowledge was distributed to 230 endodontic residents and returned with a 32% response rate. The overall mean resident knowledge score was 42.3% (SD, 17.5%; range, 10% to 90%). Only 39% stated they understood all of the statistical terms encountered in journal articles. This data supports the hypothesis that there exists a lack of understanding of biostatistical principles and would suggest that more effective training in biostatistics in residency education is desirable.

A survey was conducted to assess the current state of predoctoral endodontic education in the United States. Fifty-one schools received surveys and 73% responded. Seventy-six percent were from public schools with most having a graduate endodontic program (84%). Preclinical training most often began in the spring of second year and clinical training started in the fall of third year (each 54%). All programs that responded stated that endodontists routinely instruct students in the clinic. Sodium hypochlorite 2.5% was the irrigation of choice. Calcium hydroxide was the most common intracanal medicament. Cold lateral condensation with gutta-percha was the most frequently indicated obturation technique. Sixty-two percent of programs had microscopes, with 1-2 cases treated with microscope per week. Findings suggest that endodontists are still an integral part of teaching predoctoral dental students in the United States.

Cracked teeth may be difficult to diagnose. Craze lines rarely become symptomatic or require treatment. Cracks in the enamel and dentin alone may or may not become symptomatic and require restorative treatment. However, cracks extending into the enamel, dentin, and pulp chamber provide an avenue for bacteria to establish infection and this commonly results in symptoms and the need for endodontic and restorative treatment. The published endodontic literature has limited information regarding the prevalence or predictive factors for cracks extending into the pulp chamber of teeth. The purpose of this study was to determine the prevalence and classification of intrapulpal cracks in maxillary premolars and to identify factors that may aid in diagnosing the existence and extent of a crack. The cracks were classified according to the Intrapulpal Crack Classification System proposed by Detar in 2014. All maxillary premolar teeth treatment planned for non-surgical root canal therapy (NSRCT) or retreatment (RETX) at Virginia Commonwealth University (VCU) Graduate Endodontic Practice from January 2014 through February 2015 were included in the study after obtaining patient consent. Teeth were examined visually, stained, and examined microscopically for the presence of an intrapulpal crack. Demographic information, subjective data associated with the chief complaint, objective results of diagnostic testing (percussion, palpation, bite stick test, transillumination, probing depths), existing restorations, pulpal diagnosis, and periapical diagnosis were analyzed using chi-square and multiple logistic regression (P

The aim of this study was to compare the incidence of root canal dentinal micro-cracks after canal instrumentation using reciprocating files (WaveOne Gold® and Twisted Adaptive®) and continuous rotation files (Edge Evolve® and EndoSequence®) in an ex-vivo benchtop study. This project used a novel methodology of finding dentinal defects using the “K-cube”, which allows evaluators to visualize sectioned root surfaces before instrumentation and after instrumentation. Mesial roots from 40 human mandibular first molars were divided into 4 groups of 10 for each file type. Root section pictures were taken with a Zeiss Discovery V20 stereomicroscope before and after canal instrumentation. Each of the pre-instrumentation and post-instrumentation images were evaluated for dentinal defects by four calibrated endodontists utilizing REDCap survey. Using a chi-square analysis, there was no statistically significant difference between dentinal defects created by continuous and reciprocating rotation (p=0.1924) and no difference between the four file types (p=0.2317).

O objetivo do presente estudo foi comparar a sensibilidade e acuidade das imagens obtidas por meio de tomografia computadorizada de feixe cônico (TCFC) com equipamentos com diferentes especificações técnicas, durante o tratamento endodôntico, tendo a microtomografia computadorizada como padrão de referência. Molares inferiores (n=14), com presença de istmo na raiz mesial, foram escaneados por microCT e por 3 diferentes tipos de TCFC, (1) Accuitomo (ACC), (2) NewTom 5G (N5G) e (3) NewTom VGi evo (NEVO), durante as 3 diferentes fases do tratamento: (1) diagnóstico e anatomia do sistema de canais radiculares (SCR), (2) pós preparo biomecânico e (3) pós obturação. Para a padronização das imagens obtidas com os diferentes aparelhos utilizou-se o programa MeVisLab. As imagens obtidas pelos quatro sistemas de imagens foram avaliadas quantitativamente pelos parâmetros bidimensionais de área, perímetro, circularidade e diâmetros maior e menor; e qualitativamente, por 2 examinadores calibrados, por meio de atribuição de escores em relação às fases do tratamento endodôntico: (1) classificação da morfologia do sistema de canais radiculares (SCR) segundo Vertucci (1984) e classificação de istmos segundo Hsu; Kim (1997); (2) presença ou ausência de debris no SCR e nas áreas de istmos e presença de perfurações radiculares e (3) qualidade da obturação no SCR e nas áreas de istmos. Os dados qualitativos foram avaliados estatisticamente por meio do teste Kappa e os quantitativos por análise de variância ANOVA e teste de Tukey, a concordância entre os dados foi verificada pelo coeficiente de correlação intercalasse (ICC) e regressão linear simples. Na fase inicial, houve concordância moderada (k=0,49) e substancial (k=0,63) entre o microCT e os TCFCs. Os TCFCs avaliados não apresentaram acuidade para a classificação dos istmos tipos II e III. Houve reprodutibilidade satisfatória entre microCT e TCFC apresentados pelos valores de perímetro, circularidade, diâmetros maior e menor (0,410,74), sendo esses valores menores para circularidade (0,410,42). O diagnóstico de debris no canal radicular e no istmo foi dificultado nas imagens do ACC (42,9%), N5G (40,0%), NEVO (40%), não mostrando concordância entre o microCT e os TCFCs (0,050,12). Após o preparo biomecânico 2,4% a 4,8% das imagens dos TCFCs demonstraram a presença de perfuração que não existia no microCT. Todos os parâmetros quantitativos analisados apresentaram reprodutibilidade excelente ou satisfatória entre o microCT e os TCFCs (0,600,76). Na avaliação da qualidade da obturação, foi possível o diagnóstico do istmo parcialmente preenchido em torno de 2,9% a 8,8% das imagens obtidas nos TCFCs quando comparados ao microCT em que foi possível o diagnóstico em torno de 26,5% das imagens, levando a uma falta de concordância entre microCT x ACC e uma concordância pobre entre microCT x 5G e microCT X NEVO. Os parâmetros, área, perímetro, diâmetro maior e diâmetro menor apresentaram concordância excelente, e as medidas da circularidade foram satisfatória, limitando a nitidez do material obturador. Os TCFCs fornecem subsídios para o diagnóstico e planejamento do tratamento endodôntico, porém é importante conhecer seus diferentes protocolos e limitações para atingir melhores resultados com menor risco e dano para o paciente / The aim of this study compared the sensitivity and acuity of the images obtained by cone beam computed tomography (CBCT) with equipment with different technical specifications during endodontic treatment, with microCT. Fourteen lower molars were evaluated, with the presence of isthmus in the mesial root. The samples were scanned by microCT and 3 different types of CBCT, (1) Accuitomo, (2) NewTom 5G and (3) NewTom VGi evo, during of the three stages of endodontic treatment, (1) initial, (2) post biomechanical preparation and (3) post-obturation. MeVisLab software was used for registration for all images. The images were analysed quantitatively by the two-dimensional parameters of area, perimeter, roudness and major and minor diameters; and qualitatively, by 2 calibrated examiners, through the assignment of choices regarding the phases of the endodontic treatment: (1) classification of root canal system (SCR) according to Vertucci (1984) and classification of isthmus according to Hsu; Kim (1997); (2) presence or absence of non-SCR debris and areas of isthmus and presence of root perforations and (3) quality of non-SCR obturation and in the isthmus areas.The qualitative data were evaluated statistically by means of the Kappa test and the quantitative variables by ANOVA and Tukey test, the agreement between the data was verified by the interclass correlation coefficient (ICC) and simple linear regression. In the initial phase, there was moderate agreement (k = 0.49) and substantial agreement (k = 0.63) between the microCT and the CBCTs. All CBCTs evaluated were not accurate for the classification of the isthmus types II and III. There was a satisfactory reproducibility between microCT and CBCT presented by the values of perimeter, roundness, major and minor diameters (0.41 0.74), lowest values for circularity (0.41 0.42). The assessment in the images of biomechanical preparation did not allow diagnosis of debris in the root canal and in the isthmus of ACC (42.9%), N5G (40.0%), NEVO (40%) and the results did not find agreement between microCT and the TCFCs (0.05 0.12). Perforations was showed in 2.4% to 4.8% the images of CBCT but not reported on microCT. The data of area, perimeter, major a minor diameter and roundness showed excellent or satisfactory reproducibility between the microCT and the CBCT (0.60 0.76). In the evaluation of the quality of the obturation, the images of the TCFC with the partially filled isthmus presented a value of 2.9% for the ACC and 8.8% for the N5G and NEVO, in this way, they did not agree the value showed in the microCT (26.5%), leading to a lack of agreement between microCT x ACC and poor agreement between microCT x 5G and microCT X NEVO. The parameters, area, perimeter, major and minor diameter presented excellent agreement, but the roundness measurements were satisfactory, making the obturator material clearer. The CBCTs provide subsidies for the diagnosis endodontic treatment, but it is important to know its different protocols and limitations to achieve better results with less risk and harm to the patient