July 2011 A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

"A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science. Endodontics, College of Dental Medicine, Nova Southeastern University, July, 2006."

Introduction: The purpose of this study was to evaluate the amount of external apical root resorption (EARR) secondary to orthodontic treatment in patients with Short Root Anomaly (SRA) using Cone Beam Computed Tomography (CBCT) at the University of the Pacific Orthodontic Clinic. Material and Methods: In this retrospective study, CBCTs of forty-eight SRA patients who underwent orthodontic treatment were selected from the graduate orthodontic clinic. CBCTs before and after treatment were analyzed to measure root length changes on the upper central and lateral incisors. Results: Differences between the two methods of assessing SRA severity occurred between categorizing mild and moderate SRA subjects with the quantitative method resulting in more moderate cases and visual method determining more mild cases. Root resorption changes ranged from 0.92-1.3 mm for all incisors. Between the Non-Hispanic and Hispanic group, there was no statistical significance for all tooth length changes. There is a statistically significant difference in the root resorption of SRA teeth and non-SRA teeth (0.55mm). Conclusions: Post orthodontic treatment SRA teeth exhibited less linear changes than non SRA teeth and no differences were found between non-Hispanic and Hispanic upper incisors.

Cone beam computed tomography (CBCT) is the recommended imaging modality of choice for evaluating previous endodontic treatment (1). The aim of this study was to compare treatment planning decisions made when evaluating previous endodontic treatment to determine if treatment planned and projected prognosis differs when digital radiography is used alone or in combination with CBCT. A retrospective chart review was conducted. Patients for whom a CBCT was taken were included in the study. Twenty-eight patients qualified. Patient’s periapical digital radiographs (Dexis©) were evaluated by 2 calibrated endodontists, a treatment plan was identified and a prognosis was projected. Later the same radiographs were viewed with CBCT scan. The CBCT provided significant information 75% of the time. CBCT provided the only information for an accurate diagnosis 17% of the time. Prognosis changed 38% of the time when CBCT was added. An unfavorable or questionable prognosis changed to favorable 30% of the time.

The aim of this study was to determine the trends in protocol, success rates, and consistency in follow up of revascularization procedures in a controlled environment. Patients of the Virginia Commonwealth University School of Dentistry were identified who were offered revascularization therapy as a treatment option on immature permanent teeth from January 1, 2010 to May 31, 2017. A total of 77 patients and 78 teeth were evaluated for revascularization therapy. For patients accepting treatment, records were reviewed for outcome assessment and consistency of follow up. A total of 30 patients (31 teeth) were treated following revascularization protocols, with only 20 patients (21 teeth) returning for follow up. Six of the 21 teeth needed some form of additional therapy due to patients remaining symptomatic, however 15/21 exhibited varying levels of success. Recall rate was 67.7%. With a success rate of 71.4%, revascularization therapy should continue to be considered for all patients with teeth having necrotic pulps and immature root apices. However, changes to recall protocols need to be improved in order to better monitor the status of teeth that undergo revascularization therapy.

The aim of this study was to evaluate whether volumetric changes in persistent periapical lesions can be detected in follow-ups six months to five years after apicoectomy using cone-beam computed tomography. Patients with a previous treatment history of apicoectomy and for whom a pre-surgical CBCT scan was taken between November 2010 and December 2015 were invited to participate in the study. A post-surgical CBCT image of the treated tooth was obtained at the recall visit. Volumetric and linear measurements of periapical lesions on initial and postoperative CBCT images were performed using DiThreshGUI software and two calibrated examiners—a board-certified endodontist and a board-certified oral radiologist. Repeated-measures ANOVA were used to estimate the magnitude of reduction and to test for differences (at alpha=0.05). A total of 20 patients with 27 surgically treated teeth were recalled at an average interval of 37 months. Reduction in the size of lesions was observed in 24 teeth (88%); overall, the volumes significantly decreased as detected by software-assisted measurement of volume (P = .0002) and by calculation from linear measurements (P < .0001). Volumetric analysis detected a reduction of 86% in lesions while the linear-derived volume measurements yielded an average reduction of 96%. These two methods of lesion assessment were strongly correlated with one another in pre-surgical scans (r>0.88) when apical lesions are measurable.

Diagnosis and treatment of teeth with longitudinal fractures is challenging. Cracks are usually not visible radiographically; they require a thorough evaluation to aid in diagnosis. Patients may be asymptomatic, demanding the dentist rely on clinical findings to make a diagnosis. Early diagnosis of the presence and extent of a crack is essential for the successful management of a cracked tooth. There is limited information in the literature regarding the prevalence or predictive factors of cracks extending into the pulp chamber of teeth. The purpose of this study was to determine the prevalence of intrapulpal cracks in maxillary molars and to identify factors that may aid in diagnosing the existence of a crack. All maxillary molar teeth requiring non- surgical root canal therapy or retreatment at the Virginia Commonwealth University graduate endodontic clinic from June 2016 through December 2016 were included in the study after obtaining patient consent. Teeth were examined visually, transilluminated, 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, and diagnosis) were analyzed using chi-square and logistic regression (p<0.05) to identify associations of these findings with the existence of a crack. A total of 18% (15/82 teeth) of maxillary molars that were evaluated and had endodontic treatment initiated were cracked. There was a significant association between cracked teeth and pain on biting (P<.0001) and with probing depths greater than 4 millimeters (mm) (P < 0.003). Those positive on a tooth slooth test were more likely to have an intrapulpal crack (P<.001) and teeth with a positive transillumination test were also found to be associated with the presence of a crack(P < .001).

The body of knowledge that exists regarding cracked teeth is limited. The purpose of this study was to determine the prevalence of cracks among extracted teeth. This retrospective longitudinal cohort study included patients of the Virginia Commonwealth University School of Dentistry that underwent extraction procedures over a 6 year period. The sample consisted of 20,408 patients and 40,870 teeth. Statistical analysis software was used to identify diagnoses of a crack, fracture, or split tooth prior to extraction of the tooth by analyzing the Electronic Health Record (EHR) (axiUm™, Version 6.03.03.1035, Exan Corporation, Vancouver, BC, Canada). There were 3,228 teeth identified as cracked in the 40,870 extracted teeth—an overall prevalence of 7.90%. The percentage of cracked teeth were compared using a chi-square test of homogeneity. The prevalence of cracked teeth varied according to tooth type (chi-square = 95.5, df = 7, p < .0001). Tukey’s multiple-comparison procedure identified the groups of tooth types with a significantly different cracked prevalence. The mandibular 2nd molar had the highest prevalence (9.72%). Age and gender were also significantly correlated with cracked teeth.

The purpose of this study was to compare the antimicrobial effect of MTAD, two of its components, doxycycline and citric acid, and NaOCl on E. faecalis in two in vitro models: the bovine tooth model and the agar diffusion model. In the tooth model, the lumens of thirty bovine dentin discs were standardized, autoclaved and infected with E. faecalis for 14 days. The infected dentin discs were treated with either MTAD, doxycycline 100mg/ml, 10% citric acid, 5.25% NaOCl or saline for 10 minutes. Dentinal shavings were collected using sterile 037 and 040 round burs. The number of bacteria in the shavings was enumerated by overnight CO2 culturing on TSA agar plates. For the agar diffusion model, E. faecalis was plated before placing paper discs wetted with three dilutions of each irrigant. The zone of inhibition was recorded after overnight culture. The data were analyzed with a two-way ANOVA and Tukey-Kramer post-hoc test. In the bovine tooth model, NaOCl and doxycycline were more effective than control in killing E. faecalis at the shallow bur depth but at the deeper bur depth, only NaOCl was significantly more effective (psE. faecalis.

Cracked teeth have long presented a diagnostic challenge. Previous investigators have considered possible predictive factors, many of which revolve around the tooth’s restorative characteristics. Few have investigated the restorative status of teeth with cracks extending into the pulp chamber. The purpose of this investigation was to determine the prevalence of the different types of restorations present in intrapulpally cracked teeth and determine any other restorative factors that may aid in predicting the presence or extent of an intrapulpal crack. Intrapulpally cracked molars requiring endodontic therapy at the VCU Graduate Endodontic Practice were included in this study. For each tooth, the type of restorative material present and surfaces involved were recorded. The Restoration Volume Proportion (RVP) was calculated to accurately quantify the size of the restoration present. Pulpal and periapical diagnoses, and intrapulpal crack classification were also recorded. Chi squared analysis and logistic regression were used to determine any significant associations. This study included 43 teeth. The study population was 65% female and the average age was 56. Of the various restoration types evaluated, 73% of teeth presented with amalgams, 12% with composites. Class I restorations were 61% of the sample. The most frequently occurring restoration size by volume was a “small” restoration. The most commonly involved teeth were the maxillary 1st molar and mandibular 2nd molar. A significant association was found between restoration size and crack classification suggesting that teeth with larger restorations had a higher incidence of coronal cracks while those with smaller restorations had a higher incidence of radicular cracks. Restoration classification and pulpal walls involved were also significantly associated suggesting that Class II restorations were most frequently associated with cracks involving a single pulpal wall while Class I restorations were evenly associated with one and two wall cracks. Other significant associations were found between tooth type and pulpal walls involved and between restoration surfaces and pulpal wall classification. This study found several significant associations between restoration characteristics and intrapulpal cracks. Further research may continue to reveal how a tooth’s restorative status may influence its risk for the presence of an intrapulpal crack.