Anne E. Williamson

Antimicrobial Susceptibility of Monoculture Biofilms of a Clinical Isolate of Enterococcus faecalis

The purpose of this study was to create a monoculture biofilm of a clinical isolate of Enterococcus faecalis and to determine susceptibility against four antimicrobial irrigants. Biofilms were subjected to 1-, 3-, and 5-minute exposures to one of the following irrigants: 6% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate (CHX) or one of two new products, <6% NaOCl with surface modifiers (Chlor-XTRA) or 2% CHX with surface modifiers (CHX-Plus) (Vista Dental Products, Racine, WI). It was hypothesized that NaOCl and CHX would be equally effective and that addition of surface modifiers would improve bactericidal activity of the respective irrigants compared to the original formulations. Results indicate that 6% NaOCl and Chlor-EXTRA were significantly superior against E. faecalis biolfilms compared to 2% CHX and CHX-Plus at all time points except five minutes.

Resistance to Cyclic Fatigue Failure of a New Endodontic Rotary File

INTRODUCTION A new nickel-titanium (NiTi) rotary file called the ProFile Vortex (PV; Denstply, Tulsa Dental Specialties, Tulsa, OK) has recently been released for endodontic use. The purpose of this study was to compare cyclic fatigue resistance of the new size 30 PV files with size 30 files of other popular brands. Other files tested include Twisted File (TF; Sybron Dental Specialties, Orange, CA), ProFile (PF; Denstply Tulsa Dental Specialties, Tulsa, OK), GTX (GTX, Denstply Tulsa Dental Specialties), and EndoSequence (ES; Brasseler, Savannah, GA). METHODS Size 30 files with a constant .06-mm/mm taper were rotated at manufacturer-recommended speed and torque settings in a simulated canal until failure. RESULTS Significant differences were found between the various brands of files. The differences between file brands may be because of a different manufacturing process or differences in file design. CONCLUSIONS Based on a simulated canal model, the PV, TF, and GTX files appear to offer greater cyclic fatigue resistance than ES and PF files.

Evaluation of Dental Pulp Sensibility Tests in a Clinical Setting

INTRODUCTION The goal of this project was to evaluate the performance of dental pulp sensibility testing with Endo Ice (1,1,1,2-tetrafluoroethane) and an electric pulp tester (EPT) and to determine the effect of several variables on the reliability of these tests. METHODS Data were collected from 656 patients seen in the University of Iowa College of Dentistry Endodontic graduate clinic. The results of pulpal sensibility tests, along with the tooth number, age, sex, number of restored surfaces, presence or absence of clinical or radiographic caries, and reported recent use of analgesic medications, were recorded. The presence of vital tissue within the pulp chamber was used to verify the diagnosis. RESULTS The Endo Ice results showed accuracy, 0.904; sensitivity, 0.916; specificity, 0.896; positive predictive value, 0.862; and negative predictive value, 0.937. The EPT results showed accuracy, 0.75; sensitivity, 0.84; specificity, 0.74; positive predictive value, 0.58; and negative predictive value, 0.90. Patients aged 21-50 years exhibited a more accurate response to cold testing (P = .0043). Vital teeth with caries responded more accurately to cold testing (P = .0077). There was no statistically significant difference noted with any other variable examined. CONCLUSION Pulpal sensibility testing with Endo Ice and EPT are accurate and reliable methods of determining pulpal vitality. Patients aged 21-50 exhibited a more accurate response to cold. Sex, tooth type, number of restored surfaces, presence of caries, and recent analgesic use did not significantly alter the results of pulpal sensibility testing in this study.

Resin-based versus gutta-percha-based root canal obturation: influence on bacterial leakage in an in vitro model system.

OBJECTIVE This study evaluated the ability of a resin-based system (Resilon/Epiphany) and gutta-percha/sealer with warm vertical or cold lateral compaction to prevent coronal leakage. STUDY DESIGN A polymicrobial suspension in a dual-chamber model was used. Seventy extracted maxillary incisors were prepared, divided into 4 groups, and obturated: Group 1, lateral compaction/gutta-percha/AH Plus; Group 2, lateral compaction/Resilon; Group 3, continuous wave compaction/gutta-percha/AH Plus; Group 4, continuous wave compaction/Resilon. Upper chambers held a mixed suspension of endodontic pathogens. Apices were suspended in the lower chambers. Leakage was determined daily for 40 days and evaluated for turbidity. Data were analyzed using survival analysis; log-rank test was used to analyze differences in time to leakage. RESULTS Median time to leakage: 16, 15, 11, and 25 days for Groups 1 to 4 respectively (P = .93, log-rank test). CONCLUSION No difference in time to leakage among the 4 treatment groups existed.

Bactericidal Activity of Stabilized Chlorine Dioxide as an Endodontic Irrigant in a Polymicrobial Biofilm Tooth Model System

INTRODUCTION The purpose of this study was to determine bactericidal efficacy of 0.04% stabilized chlorine dioxide, 3% sodium hypochlorite, 2% chlorhexidine gluconate, and sterile distilled water in a polymicrobial biofilm model. METHODS Roots of 35 permanent bovine incisors had pulps extirpated, and their apical size and root length were standardized. Teeth were coated with mucin, inoculated with standardized suspensions of Streptococcus sanguinis, Actinomyces viscosus, Fusobacterium nucleatum, Peptostreptococcus micros, and Prevotella nigrescens and incubated anaerobically. Teeth were randomly divided into four groups and rinsed for 3 minutes with 15 mL of irrigant. Biofilms were harvested and spiral-plated on selective media. Numbers of bacteria in the harvested biofilms was determined via the standard spiral-plating methodology. Treatment groups were evaluated using the nonparametric Kruskal-Wallis procedure. Pair-wise comparisons among the four groups and five organisms were made using the Wilcoxon-Mann-Whitney procedure. Adjustments for multiple comparisons were made using the Holm method with p < 0.05. RESULTS Results provide strong evidence of a significant difference in levels of bactericidal activity associated with the type of irrigant for all five bacterial species tested. Levels of bactericidal activity were significantly higher for the NaOCl group than for the stabilized chlorine dioxide (ClO₂) group for S. sanguinis, A. viscosus, and P. nigrescens. Results for F. nucleatum and P. micros were not significant after the adjustment for multiple comparisons. CONCLUSIONS The triple-inoculation bovine tooth model system is a robust, consistent, and reproducible model system to study polymicrobial biofilms. It should be used with the knowledge expansion of biofilm structure and function as well as the development of antimicrobial protocols.

Vital Signs of the Emergency Patient with Pulpal Necrosis and Localized Acute Apical Abscess

Vital signs aid in assessing patient health and the disease severity. The objectives of this study were to determine changes in vital signs of patients with pulpal necrosis (PN) and acute apical abscess (AAA). The vital signs measured at the emergency visit were blood pressure, heart rate, temperature, and lymphadenopathy. Visual analogue scales (VASs) were used to assess (1) pain and (2) malaise. Emergency treatment was rendered. At a subsequent (baseline) visit and with clinical symptoms resolved, systemic vital sign measurements and VASs were repeated. The presence or absence of swelling with vital signs and VASs of pain and swelling were compared. Compared with baseline, data showed no marked elevation in temperature, blood pressure, or lymphadenopathy, regardless of presence or absence of swelling. VAS measurements of pain and malaise did show statistically significant higher numbers at the emergency appointment, indicating a difference from baseline. Swelling versus no swelling did not differ. Vital signs were not impacted by localized AAA, although pain and malaise were greater. Vital signs might not be useful determinants of treatment or pharmacotherapeutic measures with localized AAA.

The Efficacy of the WaveOne Reciprocating File System versus the ProTaper Retreatment System in Endodontic Retreatment of Two Different Obturating Techniques

Introduction This ex vivo study aimed to evaluate the efficacy of retreating GuttaCore (Dentsply Tulsa Dental Specialties, Tulsa, OK) and warm vertically condensed gutta‐percha in moderately curved canals with 2 different systems: ProTaper Universal Retreatment (Dentsply Tulsa Dental) and WaveOne (Dentsply Tulsa Dental). Methods Eighty mesial roots of mandibular molars were used in this study. The mesiobuccal canals in each sample were prepared to length with the WaveOne Primary file (Dentsply Tulsa Dental). The canals were obturated with either a warm vertical approach or with GuttaCore and divided into 4 retreatment groups with the same mean root curvature: warm vertical retreated with ProTaper, warm vertical retreated with WaveOne, GuttaCore retreated with ProTaper, and GuttaCore retreated with WaveOne. The warm vertical groups were obturated using a continuous‐wave technique of gutta‐percha compaction, and the GuttaCore groups were obturated according to the manufacturers instructions. After allowing sealer to set, each specimen was retreated with either the ProTaper Universal Retreatment files D1, D2, or D3 or with the WaveOne Primary file to the predetermined working length. The time taken to reach the working length was recorded. Instrument fatigue and failure were also evaluated. Results The post hoc 2‐sample t tests showed that the overall mean total time taken to reach the working length for the warm vertical groups was significantly greater than that observed for the GuttaCore groups (mean = 87.11 vs 60.16 seconds, respectively), and the overall mean total time taken to reach the working length for WaveOne was significantly greater than that observed for ProTaper (99.09 vs 48.18 seconds, respectively). Two‐way analysis of variance showed a significant main effect for both the type of experiment groups (F1,76 = 15.32, P = .0002) and the type of retreatments (F1,76 = 54.67, P < .0001). Also, the WaveOne Primary file underwent more separations than the ProTaper files. Conclusions The WaveOne Primary file underwent more separations and was unable to remove gutta‐percha as efficiently as the ProTaper Universal Retreatment files. Also, canals obturated with GuttaCore were retreated more efficiently and with fewer file separations than the canals obturated using continuous wave of warm gutta‐percha. HighlightsWaveOne Primary was unable to remove gutta‐percha as efficiently.WaveOne Primary underwent more file separations and unwindings.Canals obturated with GuttaCore were able to be retreated more efficiently.Canals obturated with GuttaCore were able to be retreated with fewer file separations and unwindings.

Endodontic Board Certification: A Review of Factors Affecting the Certification Rate

Introduction Board certification identifies clinicians who possess advanced proficiency and expertise within their field. Only 23% of endodontists are board certified (the lowest among all dental specialties). The aim of this study was to determine the factors that influence endodontists’ decisions regarding the completion of board certification. Methods A 16‐question survey was e‐mailed to 5073 US endodontists and residents who are American Association of Endodontists members. Results A total of 1603 endodontists and residents responded, corresponding to an overall response rate of 31.6%. Of those respondents, 73.8% felt board certification was important. Among endodontists, 32% were board certified, 24.4% had plans of becoming board certified, and 43.6% had no plans to become board certified. The most common reasons for not pursuing board certification were “graduated too long ago,” “don’t have time,” “process is too long,” and “not required to become an endodontist.” Board‐certified endodontists were more likely to believe board certification was important compared with their non–board‐certified counterparts (97.5% vs 60.3%, P < .0001), and were more likely to have received training at programs that encouraged and provided assistance in completion of the certification process. Residents were more likely to plan on becoming certified compared with non–board‐certified endodontists (89.6% vs 35.9%). Conclusions Despite widespread agreement regarding the importance of board certification, a strikingly low percentage of endodontists are board certified. Views provided by endodontists and endodontic residents provide insight that may be used to guide changes that will effectively increase the percentage of board‐certified endodontists.

Comparison of Mechanical and Indirect Ultrasonic Placement Technique on Mineral Trioxide Aggregate Retrofill Density in Simulated Root-end Surgery

INTRODUCTION The objective of this study was to evaluate the density of mineral trioxide aggregate (MTA) root-end filling placed by either manual condensation or manual condensation with indirect ultrasonic activation under simulated root-end surgery conditions in vitro. METHODS Extracted human molar teeth were obtained and sectioned to provide single-rooted samples (n = 50). Roots were instrumented to a size of 40 with a .04 taper and obturated with a warm vertical technique. The coronal end of each root was embedded in resin. A root-end resection and root-end preparation were completed on each root. Samples were randomly assigned to receive root-end fillings with ProRoot MTA (Dentsply, Tulsa, OK) by 1 of 2 techniques: manual condensation alone (group M, n = 25) or manual condensation with indirect ultrasonic activation (group U, n = 25). MTA was placed incrementally to the level of the root end using the enumerated technique. Samples were weighed immediately before and after filling placement. MTA was removed from all samples so as not to change the root-end preparation, rinsed, and dried. Each sample then underwent MTA placement by the opposite technique, and weight was again measured immediately before and after MTA placement. MTA filling weights for each technique were analyzed statistically using a technique for repeated measures analysis. Statistical analysis was conducted to account for any carryover or order effects. RESULTS After adjustment for carryover effects, it was found that regardless of the order of placement, the mean fill weight of MTA produced by the indirect ultrasonic method was on average 4.42 mg heavier than that produced by manual condensation alone. This result was statistically significant (P < .0003). CONCLUSIONS Under simulated root-end surgery conditions, indirect ultrasonic condensation of MTA root-end fillings was shown to produce a filling that was significantly denser than MTA placed by manual condensation alone.