Indiana University-Purdue University Indianapolis (IUPUI) / The effects of hydroxyapatite in a DAP-loaded MC carrier on dental pulp stem cells Introduction: Regenerative endodontic procedures (REP) require disinfection techniques to eliminate bacteria from the infected immature root canal system and promote new growth of the pulp-dentin complex. Double antibiotic paste (DAP), a mixture of ciprofloxacin and metronidazole, has shown efficacy in doing so while minimizing cytotoxicity on dental pulp stem cells (DPSC). Stem cells, scaffolding, and growth factors are necessary in the maturation, proliferation, and differentiation of mesenchymal stem cells into the root canal system. Nano-hydroxyapatite (n-HA) has a history of biocompatibility and, in addition, has shown promising effects as a tissue bioengineering material. Objective: The aim of this in vitro study was to investigate the proliferation and mineralization of DPSC in the presence of 1% DAP and methylcellulose (MC) with varying concentrations of nano-hydroxyapatite. Materials and Methods: DPSC were plated in 24-well plates containing culture media. The next day, semi-permeable 0.1 mm Transwell chambers were inserted into the wells to separate the reservoirs for medicaments. Treatment paste composed of methylcellulose containing 1% DAP with either 0.25%, 0.50%, or 1.0% nano-hydroxyapatite was added along with culture media. Methylcellulose alone and calcium hydroxide (Ultracal) were used as control groups. After 3 days, cells were evaluated for cytotoxic effects using an MTS proliferation assay (n = 10, in triplicate). DPSCs were also cultured with these medicaments for 7 days in osteogenic media and evaluated for alkaline phosphatase (ALP) activity and mineralization activity (n = 13, in triplicate). Comparisons between groups for differences in mineralization, BSA, and ALP activity were performed using analysis of variance (ANOVA), with different variances allowed for each group and a random effect included in the model to account for correlation within each of the three trials. A simulation-based model was used to adjust for multiple comparisons. Results: Addition of n-HA treatment groups increased mineralization significantly greater than calcium hydroxide, with MC alone and MC+DAP+0.5% HA providing the greatest effect. Regarding ALP, all HA concentrations performed significantly greater than MC and DAP concentrations. Proliferation demonstrated similar metabolic activity in all experimental groups with few comparisons significant. Conclusion: The challenge in REPs is to maintain survival, and preferably promote the proliferation and development of DPSCs into the pulp-dentin complex with a consistent treatment outcome. The combination of DAP with hydroxyapatite may allow for both disinfection and improved mineralization and cellular differentiation. This contribution has shown significant ability to increase stem cell differentiation into an osteogenic lineage as well as calcium deposition, indicating end goal results of regenerative procedures.

The purpose of this study was to determine duration time, breakage and apical displacement, whilst using six different endodontic filing systems to prepare molar teeth. A total of 96 molar teeth were used in the study, divided equally, ie 16 teeth per system selected randomly, totalling 48 canals per system. A standardised access cavity was prepared for all the teeth before selection. The canals were filed according to the manufacturers&rsquo / guidelines. The result showed that PROTAPER&reg / , K3&trade / and the combination of: HERO Shaper&reg / , HERO Apical&reg / and Endoflare&reg / (Referred from hereon as HERO System for convenience) were statistically faster than PROFILE&reg / and FlexMaster&reg / , which were in turn faster than AETTM. Although breakage did occur in K3&trade / and HERO System this was not deemed statistically significant. Apical displacement occurred in the form of Type 1 in the AETTM, PROFILE&reg / and HERO System, but once again this was not statistically significant. It was concluded that more aggressive cutting features such as a positive rake<br /> angle, pyramidal shaped tip, progressive taper and absence of radial lands, if present, could have enabled K3&trade / , HERO System and PROTAPER&reg / to have faster times, and in addition these features did not compromise these systems with regard to apical foramina transportation and breakage.

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.

The objective was to determine the prevalence of vital teeth requiring non-surgical root canal therapy (NSRCT) that present with radiolucencies in mature permanent teeth in a pediatric population. A retrospective electronic dental chart review of children treated with NSRCT at VCU’s School of Dentistry between November 30, 2009 and March 1, 2013 was conducted. The presence or absence of a periapical radiolucency was determined from digital radiographs by three calibrated dentists. Specific characteristics of each tooth were collected. Statistical analysis using logistic regression was completed on all teeth with radiolucencies and vital teeth with radiolucencies. NSRCT was completed on 551 teeth. Radiolucencies were present in 246 teeth. Vitality data on access was only available in 184 teeth. In these, the prevalence of vital teeth with radiolucencies was 45.1% (n=83). Significant differences were noted for tooth type, gender, and puberty. Post-pubertal subjects had more vital teeth with radiolucencies than pubertal subjects.

The electric pulp test (EPT) has been shown to be a valuable tool in assessing pulp vitality. One of its drawbacks, however, is its high number of false positives. The purpose of this study was to determine if qualifying the type of sensation elicited by the test could lower the percentage of false positive responses. A retrospective chart review of an eleven-month period was conducted, examining all patients with necrotic teeth tested with the EPT. Of 189 teeth, when the patient responded to EPT at first sensation 23.3% of teeth were incorrectly identified as vital. When the patient was asked to respond only if they felt an uncomfortable sensation, the false positive rate was lowered to 8.5%, a statistically significant difference. No association was found between the teeth reclassified as necrotic and age, gender, type of tooth, or number of canals.

There is no universal protocol for diagnosing, treating and managing cracked teeth. The purpose of this survey was to investigate the use of traditional methods of crack detection and to explore how treatment decisions were made using an intrapulpal crack classification. The electronic survey was sent to 1115 active members of the American Association of Endodontists (AAE) and The Digital Office (TDO™) community. Comparisons were assessed using logistic or repeated-measures regression. The most often used diagnostic method was probing. When the crack involved one wall, 85% of respondents would complete root canal therapy > 50% of the time or always. For two or more walls, the percentage dropped to 44%. When the crack involved the floor or orifices, 60% would not complete treatment. For necrotic teeth, 36% of respondents preferred extraction as opposed to 3% if vital. This survey illustrated the anecdotal nature of detection, diagnosis and management of cracked teeth.

The purpose of this study was to test the number of rotations to fracture of the M-Wire GT® Series X(TM) rotary files compared to the original ProFile® GT® rotary files in a simulated curved canal. Eighty GT® Series X(TM) files of 25mm length were divided into eight groups of ten, one for each of the new GT® Series X(TM) files. Eighty original ProFile® GT® files of 25mm length were divided into eight groups of the same tip and taper sizes consistent with the GT® Series X(TM) file groups. Files were rotated at 300 rpm. While the angle may have slightly changed due to the flexure property of the file, the angle was the same for each file with the same tip and taper. The time to fracture was recorded and rotations to fracture were calculated. The data collected was analyzed using a two-way ANOVA, followed by specific post-hoc contrasts comparing the two brands for each tip and taper combination. The results show the M-Wire GT® Series X(TM) files were significantly more resistant to fracture by cyclic fatigue than the ProFile® GT® rotary instruments for the following tip and taper sizes: 20/.04, 30/.04, 30/.06, 30/.08, and 40/.08. The following tip and taper sizes: 20/.06, 40/.04, and 40/.06 were not statistically significant.

The purpose of this study was to determine what factors influence dentists when deciding whether to place an implant or perform endodontic retreatment. Null hypothesis: Dentists today are no more likely to place an implant than to perform endodontic retreatment. A twelve-item questionnaire was mailed to 525 general dentists and specialists who are members of the Richmond Dental Society. Response rate was 61.9%. The questionnaire included items on demographics, practice profile and cases of failing endodontic therapy which participants were asked to consider and chose between endodontic retreatment or implant placement. The relationship between the treatment choices and the characteristics of each dentist was assessed using a chi-square analyses and logistic regression analyses. Generally practitioners preferred retreatment (66%). This preference for retreatment varied between 25.5% and 85.9%. Associations were found between years of experience and implant use. In those practitioners with 10 years or less experience the odds of choosing an implant were higher than practitioners with more than 10 years of experience. Associations were also found between those who place implants vs. those who do not. The odds of choosing an implant verses retreatment were lower in those who did not place implants versus those who did. In conclusion, it appears that clinicians participating in this study in general still consider endodontic retreatment to be a viable treatment option prior to implant placement. However, this varies greatly with years of experience and the use of implants in practice.