Interdisciplinary approach to education: preparing general dentists to manage dental trauma.

The traditional dental curriculum presents limited opportunities for students to evaluate and treat patients with acute dental trauma. In an effort to increase student experiences, faculty at a dental school initiated and taught an interdisciplinary trauma course from 2014 to 2016. This course was elective, offered in the final year of dental school, and combined student-led and faculty-led case-based discussions of management of traumatic dental injuries with hospital trauma call shadowing. Modifications of the course were made based on student feedback. Preliminary data from student surveys showed a favorable opinion of the course. Attendees were exposed to a higher number of acute traumatic injuries and they expressed greater confidence in their diagnosis and management abilities than their peers.

Bond strength of silorane- and methacrylate-based composites to resin-modified glass ionomers.

This study evaluated the shear-bond strength of a resin-modified glass ionomer (RMGI) restorative material to a new silorane-based composite and a methacrylate-based composite in a sandwich technique with various combinations of surface treatments and bonding agents. Two composites, 2 bonding agents and 4 surface preparations were used to create 16 groups with 10 specimens each. After 24 hours storage at 37°C in 100% humidity, the specimens were tested for shear bond strength; means and standard deviations were determined per group. Surface modifications did not affect the shear-bond strength of the silorane or methacrylate composites to the RMGI. The new silorane composite had significantly lower bond strength to the RMGI compared to the methacrylate composite. The new silorane system adhesive agent had significantly higher bond strength to the RMGI compared to the methacrylate adhesive agent. The greatest bond strengths to the RMGI were produced when using the silorane system adhesive agent with the methacrylate composite.

Kovanaze Intranasal Spray vs Traditional Injected Anesthetics: a Study of Pulpal Blood Flow Utilizing Laser Doppler Flowmetry.

OBJECTIVE: An ideal local anesthetic would be effective, minimally reduce pulpal blood flow (PBF), and not require injection. This study compared the effects of 3% tetracaine plus 0.05% oxymetazoline nasal spray (Kovanaze; KNS) and injections using 2% lidocaine with 1:100,000 epinephrine (LE) or 3% mepivacaine plain (MP) on PBF, anesthetic efficacy, and participant preference. METHODS: In a double-blind cross-over design, 20 subjects randomly received a test anesthetic and placebo at each of 3 visits (KNS/mock infiltration; mock nasal spray/LE; or mock nasal spray/MP). Nasal sprays and infiltration apical to a maxillary central incisor were delivered ipsilaterally. PBF was evaluated by laser Doppler flowmetry, and local anesthetic success was assessed with electric pulp testing. Postoperative pain levels, participant preference, and adverse events were also assessed. RESULTS: LE injections demonstrated significant reductions in PBF at all time intervals compared with baseline (P < .05), whereas KNS and MP did not. Pulpal anesthesia success rates were higher for LE (85%) compared with MP (35%) and KNS (5%). Participants reported significantly higher postoperative pain levels for KNS compared with LE and MP. Additionally, KNS was the least preferred of the anesthetics administered and resulted in more reported adverse events. CONCLUSION: Although KNS showed no significant effect on PBF, it was not effective in achieving pulpal anesthesia as used in this study.

Effect of repeated refrigerant spray applications using various carriers on pulpal temperature change.

This study sought to determine how repeated applications of a refrigerant spray on various cotton carriers affected the change in pulpal temperature. A thermocouple was placed at the roof of the pulp chamber of a human maxillary canine and connected to a thermometer logging at one-second intervals while the root was immersed in a water bath at 37 degrees C. Four different carrier types were used: large cotton pellets, small cotton pellets, cotton-tip applicators, and cotton rolls. Each carrier was sprayed with 1,1,1,2-tetrafluoroethane and placed on the crown for five seconds. Pulpal temperature change was recorded after each five second application of the same carrier to the tooth until a total of six consecutive sprays and applications of the carrier were applied. Each carrier group consisted of 10 performances of the six sets of readings (n = 10). The difference between baseline and the low temperature reading was calculated to determine the temperature change (in degrees C) in the pulp chamber per application. When the refrigerant spray was used, the large cotton pellet carrier generally produced the largest decrease in pulpal temperature at each repeated application compared to the other types of carriers. However, the same large cotton pellet should not be sprayed with the refrigerant more than two times before it is replaced.

Shear Bond Comparison between 4 Bioceramic Materials and Dual-cure Composite Resin.

INTRODUCTION: Bioceramic materials have shown biologic and physical properties favorable for regenerative treatment. A key to treatment success is an adequate restoration to prevent microleakage; however, research is limited regarding the bond strength between restorative and bioceramic materials used in regenerative procedures. This study compared the bond strength between 4 bioceramic materials and a dual-cure composite resin. METHODS: Eighty wells in Teflon (ePlastics, San Diego, CA) blocks were filled with bioceramic materials representing 4 groups: White ProRoot mineral trioxide aggregate (MTA) (Dentsply Tulsa Dental, Tulsa, OK), Biodentine (Septodont, Saint Maur des Fosses, France), EndoSequence Root Repair Material Fast Set Putty (Brasseler USA, Savannah, GA), and NeoMTA (Avalon Biomed Inc, Houston, TX). After allowing samples to set according to the manufacturers' instructions, exposed surfaces of the bioceramic materials were prepared using ClearFil SE Bond (Kuraray America, Inc., New York, NY) followed by restoration with ClearFil DC Core Plus (Kuraray America, Inc.). To test shear bond strength, each block was secured in a universal testing machine, and the crosshead was advanced at 0.5 mm/min until fracture. Newton peak force was recorded and megapascals calculated followed by data comparison. RESULTS: The mean shear bond strengths between ClearFil DC Core Plus and the bioceramic materials were as follows: White ProRoot MTA, 7.96 MPa; Biodentine, 9.18 MPa; EndoSequence Root Repair Material Fast Set Putty, 4.47 MPa; and NeoMTA, 5.72 MPa. White ProRoot MTA and Biodentine were statistically similar, with a higher stress bond strength than NeoMTA, which had a statistically greater bond strength than EndoSequence Root Repair Material. All these values were lower than typical bond strengths shown for dentin-composite resin bonding. CONCLUSIONS: The choice of which bioceramic material to use in regenerative procedures should be based on factors other than the bond between that material and the overlying coronal resin restoration.

The Effects of Irrigants on the Survival of Human Stem Cells of the Apical Papilla, Including Endocyn.

INTRODUCTION: Endocyn, a pH-neutral solution of hypochlorous acid and hypochlorite has been developed for use as an endodontic irrigant. The purpose of this study was to evaluate the effect of Endocyn on human periodontal ligament (PDL) fibroblasts, rat osteosarcoma cells (UMR-106), and stem cells of the apical papilla (SCAP) compared with other commonly used endodontic irrigants. METHODS: To determine cytotoxicity, cells were exposed to various concentrations of Endocyn, 6% sodium hypochlorite (NaOCl), 17% EDTA, and 2% chlorhexidine for 10 minutes, 1 hour, or 24 hours. Cell survival was measured fluorescently using calcein AM. Endocyn also was tested for its ability to inhibit SCAP proliferation and alkaline phosphatase activity. Finally, SCAP transcript expression was examined via reverse-transcriptase polymerase chain reaction. RESULTS: Endocyn was no more toxic to PDL and UMR cells than water for up to 24 hours. Endocyn concentrations of 50% were toxic to SCAP after 1 hour of exposure. Endocyn concentrations of >20% inhibited SCAP proliferation, whereas concentrations of ≥10% inhibited alkaline phosphatase activity. Exposure of SCAP to 10% Endocyn for 3 days did not alter most transcript expression, but did significantly reduce the expression of alkaline phosphatase, fibromodulin, and osteomodulin. CONCLUSION: Endocyn was significantly less cytotoxic to PDL, UMR-106, and SCAP cells compared with other commonly used endodontic irrigants. High concentrations of Endocyn did inhibit some transcript expression and alkaline phosphatase activity, indicating a potential reduction in the osteogenic potential of stems cells exposed to Endocyn.

Accuracy of Cone-beam Computed Tomographic Image Interpretation by Endodontists and Endodontic Residents.

INTRODUCTION: Limited field cone-beam computed tomography (CBCT) imaging has become a modality frequently used by endodontists to evaluate the teeth and surrounding tissues of their patients. Accurate image interpretation is vital to obtain needed treatment information as well as to discern coincidental findings that could be present. The goal of this study was to determine the accuracy of CBCT volume interpretation when performed by endodontists and endodontic residents. METHODS: Eighteen deidentified limited field CBCT scans were obtained and evaluated by an oral and maxillofacial radiologist and an endodontist experienced in reading CBCT images. Their collective findings were combined as the "gold standard" of interpretation for this investigation. Using standard CBCT software, 4 practicing endodontists and 5 second-year endodontic residents evaluated each scan and recorded any notable findings and whether or not each scan warranted referral to a radiology specialist. Their interpretations were then compared with the gold standard to determine accuracy and any significant differences among the groups. RESULTS: The overall accuracy was 58.3% for endodontists and 64.3% for residents. Paired t tests showed no statistically significant differences in accuracy between the 2 groups for findings in teeth or in bone, but residents were significantly better for maxillary sinus findings. Endodontists agreed with the gold standard 38.9% of the time and residents 49.8% of the time on necessity of referral. The Cohen kappa coefficient showed moderate agreement between the groups. CONCLUSIONS: Endodontists and residents had similar accuracy in CBCT scan evaluation. More training and experience are warranted for both groups in order to maximize image assessment accuracy.

A Comparison of Coronal Tooth Discoloration Elicited by Various Endodontic Reparative Materials.

INTRODUCTION: The purpose of this study was to evaluate coronal tooth discoloration of ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN), white ProRoot MTA, EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Angelus (Angelus Solucoes Odontologicas, Londrina, Brazil), and Biodentine (Septodont, Saint Maur des Fosses, France) when used in an ex vivo pulpotomy model. METHODS: Freshly extracted mandibular third molars were collected and stored in 1% chloramine-T solution. Teeth were randomly assigned into 6 groups (n = 15) and stored individually in phosphate buffered saline at 37 °C in 100% humidity. A standardized endodontic access was made in 5 groups. A 3-mm-thick increment of reparative material was placed on the pulpal floor, covered by glass ionomer, and the access opening restored with composite. Color (Commission Internationale de l'eclairage L*a*b*) was recorded with the Vita Easy Shade spectrophotometer (VITA Zahnfabrik, Bad Säckingen, Germany) on the midbuccal surface at baseline; after access preparation; after material placement; and then after 1, 7, 30, and 60 days. Changes in Commission Internationale de l'eclairage L*a*b* were measured for each experimental group and compared with ProRoot MTA (positive control) and no treatment (negative control) using the following equation: ΔE = ([Li - L0*]2 + [ai - a0*]2 + [bi - b0*]2)(1/2). The mean results were analyzed within each group and between groups using the Friedman 2-way analysis post hoc test (P < .05). RESULTS: There were no significant differences between white ProRoot MTA, MTA Angelus, and the positive control group. EndoSequence Root Repair Material and Biodentine produced significantly less discoloration than white ProRoot MTA, MTA Angelus, and ProRoot MTA. CONCLUSIONS: Under the conditions of this study, EndoSequence and Biodentine had significantly less discoloration compared with white ProRoot MTA, MTA Angelus, and ProRoot MTA. The potential for discoloration may or may not correlate when materials are used clinically.

Evaluation of 4 Commercial Viewing Devices for Radiographic Perceptibility and Working Length Determination.

INTRODUCTION: This study compared images displayed on 1 desktop monitor, 1 laptop monitor, and 2 tablets for the detection of contrast and working length interpretation, with a null hypothesis of no differences between the devices. METHODS: Three aluminum blocks, with milled circles of varying depth, were radiographed at various exposure levels to create 45 images of varying radiographic density. Six observers viewed the images on 4 devices: Lenovo M92z desktop (Lenovo, Beijing, China), Lenovo Z580 laptop (Lenovo), iPad 3 (Apple, Cupertino, CA), and iPad mini (Apple). Observers recorded the number of circles detected for each image, and a perceptibility curve was used to compare the devices. Additionally, 42 extracted teeth were imaged with working length files affixed at various levels (short, flush, and long) relative to the anatomic apex. Observers measured the distance from file tip to tooth apex on each device. The absolute mean measurement error was calculated for each image. Analysis of variance tests compared the devices. Observers repeated their sessions 1 month later to evaluate intraobserver reliability as measured with weighted kappa tests. Interclass correlation coefficients compared interobserver reliability. RESULTS: There was no significant difference in perceptibility detection between the Lenovo M92z desktop, iPad 3, and iPad mini. However, on average, all 3 were significantly better than the Lenovo Z580 laptop (P values ≤.015). No significant difference in the mean absolute error was noted for working length measurements among the 4 viewing devices (P = .3509). CONCLUSIONS: Although all 4 viewing devices seemed comparable with regard to working length evaluation, the laptop computer screen had lower overall ability to perceive contrast differences.

Evaluation of 4 Different Irrigating Systems for Apical Extrusion of Sodium Hypochlorite.

INTRODUCTION: The aim of this study was to evaluate NaOCl apical extrusion by using negative apical pressure (EndoVac), sonic agitation (EndoActivator), side-vented needle (Max-i-Probe), and photon induced photoacoustic streaming (PIPS 10 mJ and PIPS 20 mJ) laser irrigation in an in vitro gel model. METHODS: Extracted mandibular and maxillary central incisors (n = 18) were prepared to size 35/.04 and 55/.04, respectively. Teeth were mounted in transparent containers with clear acrylic and suspended in a color-changing pH-sensitive gel, creating a closed system. By using a crossover design, each tooth was sequentially irrigated by using 6% NaOCl with each device following manufacturers' recommendations. Each tooth served as its own control. Pre-irrigation and post-irrigation buccal and proximal view photographs served to measure the longest distance of extrusion and were analyzed with ImageJ software. Mean results were analyzed by using Kruskal-Wallis and Dunn post hoc test (P < .05). RESULTS: There were no significant differences between EndoVac, EndoActivator, and the passive extrusion groups. The EndoVac and EndoActivator groups produced significantly less extrusion than PIPS irrigation. Max-i-Probe extrusion results were more variable than those of EndoActivator but had no significant difference. Across all irrigation systems, there were no significant differences with respect to apical preparation size. CONCLUSIONS: Under the in vitro conditions of this study, no difference was found between the 10 mJ and 20 mJ PIPS laser groups. EndoVac demonstrated significantly less potential for apical extrusion than PIPS and Max-i-Probe, whereas apical preparation size did not significantly affect extrusion of irrigant. The potential for apical extrusion of endodontic irrigants should be a consideration when selecting a system for final irrigation.

Effect of repeated simulated clinical use and sterilization on the cutting efficiency and flexibility of Hyflex CM nickel-titanium rotary files.

INTRODUCTION: Recent nickel-titanium manufacturing processes have resulted in an alloy that remains in a twinned martensitic phase at operating temperature. This alloy has been shown to have increased flexibility with added tolerance to cyclic and torsional fatigue. The aim of this study was to assess the effect of repeated simulated clinical use and sterilization on cutting efficiency and flexibility of Hyflex CM rotary files. METHODS: Cutting efficiency was determined by measuring the load required to maintain a constant feed rate while instrumenting simulated canals. Flexibility was determined by using a 3-point bending test. Files were autoclaved after each use according to the manufacturer's recommendations. Files were tested through 10 simulated clinical uses. For cutting efficiency, mean data were analyzed by using multiple factor analysis of variance and the Dunnett post hoc test (P < .05). For flexibility, mean data were analyzed by using Levene's Test of Equality of Error and a general linear model (P < .05). RESULTS: No statistically significant decrease in cutting efficiency was noted in groups 2, 5, 6, and 7. A statistically significant decrease in cutting efficiency was noted in groups 3, 4, 8, 9, and 10. No statistically significant decrease in flexibility was noted in groups 2, 3, and 7. A statistically significant decrease in flexibility was noted in groups 4, 5, 6, 8, 9, 10, and 11. CONCLUSIONS: Repeated simulated clinical use and sterilization showed no effect on cutting efficiency through 1 use and no effect on flexibility through 2 uses.

Comparison of the surface hardness among 3 materials used in an experimental apexification model under moist and dry environments.

INTRODUCTION: Procedures used in single-visit or multiple-visit approaches to apical barrier creation were used with an experimental apexification model to test the surface hardness of 3 materials. The purpose of this study was to examine the microhardness of the materials after setting in moist or dry conditions. METHODS: A simulated open apex and periapical environment model was created using polyethylene tubes placed into a porous block filled with phosphate-buffered saline. White ProRoot Mineral Trioxide Aggregate (MTA; Dentsply Tulsa Dental, Tulsa, OK), EndoSequence Root Repair Material (ESRRM; Brasseler USA, Savannah, GA), and Biodentine (BD; Septodont, Louisville, CO) were mixed and placed into the apical 4 mm of the tubes (N = 15). The moist group had a damp cotton pellet above the test materials (mineral trioxide aggregate or ESSRM) with Fuji II LC (GC America, Alsip, IL) sealing the coronal segment. The dry group had gutta-percha placed directly against the test materials with amalgam sealing the coronal segment. After 10 days of storage in 100% humidity at 37°C, samples were sectioned, and microhardness was independently measured at 2 mm and 4 mm from the apical end. Differences were assessed using analysis of variance and a Tukey post hoc test (α = .05). RESULTS: Analysis of variance analyses showed no significant effect of wet or dry conditions on resultant material hardness. A Tukey post hoc test showed that using ESRRM and BD would not result in a significant difference in hardness, but using MTA would result in statistically significant different hardness values when compared with ESRRM or BD. CONCLUSIONS: Either a moist or dry environment could allow hardening of materials; thus, both methods could be acceptable for clinical treatment procedures.