POTENTIAL ANTIMICROBIAL METHODS FOR PROVISIONALIZING TEETH AFTER ENDODONTIC TREATMENT By Laura T. Garden, DDS A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, 2018 Thesis Advisor: Garry Myers, DDS Department of Endodontics Objective:To evaluate the effectiveness of a Chlorhexidine soaked cotton pellet on bacterial leakage. Methods: Fifty-one extracted teeth, including six controls, were instrumented, obturated, and sealed with either a cotton pellet (CP), 2% Chlorhexidine soaked cotton pellet (CHX), or a Permaflo orifice barrier (OB). Each root was suspended between two chambers: the coronal chamber inoculated with brain heart infusion broth and colony-forming units of Enterococcus faecalis, the apical chamber with brain heart infusion broth and phenol red. The latter was checked daily for turbidity, indicating bacterial leakage. Results: All open and closed control groups had leaked by day 7. The average CP tooth survived for 13.1 days whereas the CHX and OB teeth leaked by an average of 5.8 days. Conclusion:There is insufficient evidence to support the use of a Chlorhexidine soaked cotton pellet. The results were not as expected and the study design should be re-evaluated.

The aim of this study was to determine the change in working length (∆WL) before and after coronal flaring and after complete rotary instrumentation as a function of canal curvature. One mesiobuccal or mesiolingual canal from each of 43 extracted molars had coronal standardization and access performed. Once the access was completed, canal preparation was accomplished using Gates Glidden drills for coronal flaring and EndoSequence files for rotary instrumentation. WLs were obtained at 3 time points: pre-instrumentation (unflared), mid-instrumentation (flared) and post-instrumentation (concluded). Measurements were made via direct visualization (DV) and the CanalPro apex locator (EM) in triplicate by a single operator with blinding across the time points. Root curvature was measured using Schneider’s technique. The change in working length was assessed using repeated-measures ANCOVA. The direct visualization measurements were statistically larger than the electronic measurements (paired t-test difference = 0.20 mm, SE = 0.037, P < .0001), although a difference this large may not be clinically important. Overall, a greater change in working length was observed in straight canals than in curved canals. This unexpected finding was attributed to the limitations of the study, specifically the confounding factor of root length. This trend was more pronounced when measured electronically than via direct visualization, especially after complete instrumentation than after coronal flaring. The overall change in working length after complete instrumentation was found to be clinically insignificant in this study. A limited amount of change in working length may be expected prior to obturation.

Purpose: The purpose of this study was to assess the radiographic changes in periapical status and analysis of healing determined using periapical radiographs (PA) versus cone beam computed tomography (CBCT) pre-operatively and at 3-64 months following endodontic treatment. Methods: Pre/post treatment radiograph and CBCT scans of patients who had NSRCT, NSReTx, or SRCT from July 2011-December 2018 at VCU Graduate Endodontic clinic were included in this study. Volumetric and linear measurements of periapical lesions on initial and recall PA and CBCT images were performed using three calibrated examiners. Changes and differences in the estimated area from PA to CBCT were compared using the Wilcoxon signed-rank test. McNemar’s chi-squared test was used to determine agreement in the proportion of lesions that were absent (0x0) between the PA and corresponding view of CBCT. This data was used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predicative value (NPV). Results: A total of 51 patients with a median healing time of 13 months were included in the analysis. Significant healing was observed on both PA and CBCT images (p-value Conclusion: Assessment using CBCT revealed a lower healing rate for all treatment categories compared with periapical radiographs. CBCT was more likely to detect the presence of a PARL, whereas a periapical radiograph would be less sensitive to detection of a PARL. Significant healing cannot be detected at an earlier point in time with PA radiographs or CBCT.

Introduction: Skeletal expansion has been a treatment modality in orthodontics and orthopedics to correct skeletal transverse discrepancies with maxillary constriction. The utilization of microimplants in conjunction with these palatal expanders offers a higher degree of pure skeletal expansion and minimizes the dental side effects. The purpose of this study is to evaluate the changes of the hard and soft tissues of the face after skeletal expansion for orthodontics. Methods: 36 patients who had received successful expansion with a microimplant assisted rapid palatal expander were compared to their pre-expansion records. All patients received CBCTs from which a 3-D analysis configuration was created to trace hard and soft tissue landmarks of the midface and nasal cavity regions. 3 judges analyzed each set of records and the average was used to calculate the amount of expansion experienced at each anatomical region. A paired T-test and Wilcoxon signed-rank test were used for statistical comparison between time points. Results: Expansion can affect all of the midfacial hard tissues that support the overlying soft tissues. Increases in skeletal width from the Frontozygomatic suture down to the maxillary alveolar bone were all significant. The nasal cavity increased in width in all locations measured. Soft tissue changes were significant at the base of the ala suggesting a widening of the nose with expansion therapy. Conclusion: Maxillary expansion with microimplant assisted expanders can have skeletal changes throughout the entire midface and may affect the width of the nasal cavity. Soft tissue changes were less pronounced, and though a widening of the base of the nose may be expected this may not be noticed by the patient.

Introduction: The aim of this study was to evaluate the frequency and amount of Ca(OH)2 extrusion in relation to the intracanal delivery technique, apical foramen size, and depth of placement. Methods: Standardized training blocks with j-shaped canals were used (n=64); half of the simulated canals were shaped to apical size #35(.06 taper) and the remaining 32 to #45(.06). The frequency and extent of Ca(OH)2 extrusion were measured relative to apical taper, the depth of insertion, and whether syringe or spiral filler was used. Blocks were immersed in pH-sensitive gel and observed for color change. The visible extent of extrusion, indicated by color change, was determined as area and expressed in mm2. Results: Extrusion of Ca(OH)2 occurred in 48/64 of the samples. At 3mm from the canal terminus, the device type had a significant effect on the frequency of extrusion, with syringe placement causing extrusion significantly (p<0.01) more frequently, irrespective of device size. Amounts of extrusion were significantly larger at 2mm short of the canal terminus (median 27.44mm2, IQR 10.02), compared to 3mm distance (median 19.69mm2, IQR 25.07; p<0.0001). Analyzed separately at 2 and 3mm distance, respectively, there was significantly more extrusion with placement using a syringe size #35 compared to spiral filler size #45. Conclusions: Considering the limits of the in vitro experimental design, a spiral filler at 500rpm, placed 3mm short of the apex found to minimize extrusion of Ca(OH)2 placed in root canals.

Introduction: Lymphoepithelial carcinoma (LEC) in the oropharynx is rare. Current understanding of the disease is derived mainly from case reports and small case series, prompting further elucidation of its epidemiology and prognostic factors that affect outcome. The aim of this retrospective cohort study was to examine demographic characteristics, clinicopathologic features, and prognostic factors in patients with oropharyngeal LEC. Methods: The U.S. National Cancer Institute’s SEER registry was queried to obtain data on patients with primary oropharyngeal LEC from 1975 to 2016. Variables examined include age at diagnosis, sex, race, year of diagnosis, primary site of tumor origin, tumor size, extent, nodal status, overall stage, tumor grade, surgical treatment, and county socioeconomic status (SES). Kaplan-Meier univariable and Cox regression model multivariable analyses were conducted to identify independent predictors of survival. Results: In total, 199 cases of primary LEC in the oropharynx were found. Overall survival rates at 2-, 5-, and 10-years were 81.0%, 74.0%, and 56.0%, respectively. Disease-specific survival rates at 2-, 5-, and 10-years were 85.0%, 80.0%, and 77.0%, respectively. Multivariable analysis identified older age at diagnosis, Black race, and tonsil primary site to be independent predictors of worse survival. Contrarily, a more recent year of diagnosis, surgical resection, and higher county SES were identified to be associated with an improved prognosis. Conclusion: Oropharyngeal LEC is a rare malignancy that is diagnosed mostly in White males in the fifth decade of life. Patient age, race, year of diagnosis, primary site of tumor origin, surgical treatment, and county SES were found to significantly affect survival. Although oropharyngeal LEC is associated with a relatively favorable prognosis, detecting disease early and including surgical resection in treatment may aid in further improving survival.

Aims Preservation of peri-cervical dentin during the preparation of endodontic access is important to prevent fractures and improve the long-term prognosis. The purpose of this study was to evaluate the impact of rotary file instrumentation (TruNatomy and XP-Endo Shaper) on peri-cervical dentin removal, depending on access size. Materials and Methods Forty 3D printed mandibular first molars, with either a small or large access design, were instrumented using TruNatomy or XP-endo Shaper file systems. Canal volumes were calculated based on micro-computed tomography data obtained pre- and post-operatively. Digital sectioning of each reconstructed volume was performed 90-degrees to the long axis at the floor of the pulp chamber at 5 levels, at the pulp chamber floor (Level 0) as well as 1 and 2mm coronally and apically of Level 0. Linear measurements were taken from the inner wall of the access cavity or canal to the outer surface of the tooth for both instrumentation techniques and compared to the unprepared control dataset. These measurements served as an approximation of remaining peri-cervical dentin after root canal instrumentation. Results Some of the coronal measurements were not reportable for the control group due to incomplete capture of the crown during the microCT scan. The remaining peri-cervical dentin thickness at the level of the pulpal floor and coronally were significantly (p<0.01) affected by the access cavity size, with the smaller access preserving more dentin in all samples. Apical to the pulpal floor, there was no significant difference between instrumentation groups at the data points evaluated. Remaining dentin thickness was largest at coronal section 1 and smallest at apical section 6 with 3.81mm (p = 0.05) and 1.84mm (p = 0.06), respectively. Conclusion Access cavity size had a significant impact on remaining dentin thickness at the level of the pulpal floor and coronally, with more remaining dentin in the conservative access group, irrespective of instrumentation technique. Future studies will evaluate dentin thickness in the furcation and mid root level, as well as apical canal transportation, and procedural errors.

Aim: The aim of this study was to evaluate the accuracy of the Wirele-X (Forum Tec, Ashkelon, Israel), a new Bluetooth-enabled electronic apex locator (EAL). The accuracy of the Wirele-X and the Root ZX II (J. Morita, Tokyo, Japan) was compared in vitro using an alginate model. Materials/Methods: Thirty-one extracted single-rooted human teeth with mature apices were decoronated at the CEJ. Under 10X magnification, actual canal lengths (ACL) were determined. The teeth were embedded in alginate and electronic canal length measurements were obtained using the Root ZX II and Wirele-X EALs. Each tooth was measured three times with both EALs. A blinded examiner measured each file with a digital micrometer to the nearest 0.01 mm. Differences between ACLs and the average measurements from the EALs were compared with Student's t test for related samples. Results: The average distance from the file tip to the apical foramen (AF) was -0.11 mm (±0.16) and -0.07 mm (±0.21) for the Root ZX II and Wirele-X systems, respectively. There were no statistically significant differences between the two apex locators in their ability to locate the AF (p > 0.05). Conclusions: Both the Wirele-X and the Root ZX II provided a high level of accuracy and reliability in locating the AF.

Introduction: When skeletal transverse discrepancies exist between the maxilla and mandible, they commonly manifest in dental malocclusion. If left uncorrected, the malocclusion can lead to periodontal issues, tooth fractures, tooth loss, or other significant dental problems. Utilization of microimplants in palatal expansion aims to correct transverse discrepancies between the maxilla and mandible by separating the palatal suture in a parallel manner aimed at maximizing skeletal changes and minimizing dental side effects. Overlying soft tissue changes can be affected by the induced skeletal changes. The purpose of this study is to evaluate skeletal expansion and the overlying soft tissue change that occurs using MARPEs (microimplant assisted rapid palatal expanders) at the end of orthodontic treatment in skeletally mature (Cervical Vertebral Maturation (CMV) ≥ 5) patients using cone-beam computed tomography (CBCT) imaging and to evaluate soft tissue changes that occur at the time of orthodontic treatment completion using CBCT imaging. Materials and Methods: CBCT scans from 19 patients who were treated using microimplant assisted rapid palatal expanders were traced and evaluated at three time points: Before orthodontic treatment (T1), post MARPE expansion with MARPE in place (T2), and after orthodontic treatment with MARPE removed. Fourteen hard tissue landmarks and six soft tissue landmarks in the midface and nasal cavity regions were traced by three judges at each time point. The traced landmark points were averaged among all three judges and comparisons were made between the three time points to see the amount of expansion that occurred at various anatomical 2 regions. Intraclass correlation coefficient (ICC) was used to evaluate inter-judge reliability for all measurements. A repeated measures ANOVA test was used for statistical comparison across all three time points and a Tukey post hoc test was used for comparison between time points. Significance was set to .05 and ICC was set to >.70. Results: Expansion with microimplant assisted rapid palatal expanders can affect the hard tissue of the midface region as well as the overlying soft tissue. Increases in skeletal width from the ANS down to the maxillary alveolar bone were statistically significant in both the short term (T1-T2) and long term (T1-T3). The nasal cavity width at inferior turbinate area increased significantly after expansion (T2) and remained increased at treatment completion (T3) and the increased soft tissue width of the alar base that presented after expansion therapy remained increased at treatment completion. Conclusion: Maxillary expansion with microimplant assisted expanders resulted in skeletal changes throughout the maxilla and led to a significant long-term increase in nasal cavity width. The soft tissue changes associated with MARPE treatment show that a widening of the base of the nose may be expected after expansion and can remain at treatment completion.

Introduction: Orthodontic and orthopedic expansion is necessary to create space to resolve crowding due to arch deficiency or tooth size discrepancy. The Invisalign First clear aligner appliance as a modality for early interceptive orthodontic treatment has become incorporated into orthodontic practices in very recent years. The present study aims to investigate the magnitude of expansion of the Invisalign First clear aligner appliance compared to a Schwartz removable expander in patients with mixed dentition. Additionally, the study aims to compare the efficacy and predictability of Invisalign First clear aligners in this population. Materials & Methods: In this retrospective study, a sample was collected from a single orthodontist practitioner. The sample consisted of 34 patients, 16 patients treated with Invisalign First clear aligners only (Group1) and 19 patients treated with a Schwartz removable appliance and Invisalign First clear aligners (Group 2). Intraoral scans of four timepoints, initial (T1), post-expansion for Group 2 only (T1Exp), first refinement (T2), and final (T3), and planned Clincheck goal (P) model from Clincheck software were imported to Align Technology’s digital measure program (Quantify©). Arch widths and molar inclinations were measured at each timepoint and the changes between timepoints were calculated. Predictability of arch expansion was calculated as T13 (change between initial and final) divided by the Planned dimension multiplied by one hundred. A two sample t-test was used to assess differences in the changes in arch widths and predictability of expansion between two groups. Results: There were statistically significant differences found in the magnitude of expansion and predictability of arch expansion between two groups. Group 2 showed a greater amount of expansion and predictability. Group 1 showed about 50-60% of the planned expansion at the end of treatment. In regards to magnitude of expansion when comparing the two groups, the efficacy predictability of transverse dimensional changes were significantly greater in the Group 2 compared to Group 1, 83% vs 56% (p = 0.001), respectively. The changes in inclination were similar in both groups, with no statistically significant differences.Conclusions: There is a significantly greater amount of expansion and greater predictability with the Schwartz removable appliance compared to the Invisalign First clear aligner appliance in the mixed dentition. The predictability of Invisalign First was 56% and indicates a significant overcorrection of arch expansion is required at the virtual treatment planning stage in Clincheck in order to obtain the arch expansion that was planned