2D and 3D Erosion Landscape Analysis of Endodontic-Treated Teeth Using EDTA and HEDP as Chelating Agents: A High-Resolution Micro-Computed Tomographic Study.

This study aimed to assess the amount of erosion during activated endodontic irrigation with either HEDP or EDTA via high-resolution micro-computed tomography. Two root canals of twenty premolars were prepared with ProTaper Next and irrigated with sodium hypochlorite. Palatal canals, which served as control groups, were sealed, while buccal canals were further irrigated with either EDTA (n = 10) or HEDP (n = 10), which served as test groups. Micro-CT was performed to measure erosion depth. For 2D and 3D measurements, non-parametric repeated ANOVA measurements and post hoc tests were performed. 2D analysis showed highly significant differences between the case groups at each position of the root (p ≤ 0.01). The cervical and apical positions showed significant differences in the EDTA group (p = 0.03). The 3D analysis also showed significant differences between both chelating agents (p < 0.01) and the case and control groups (p = 0.01). The mean erosion depths in the cervical, middle, and apical thirds of the EDTA group were 45.75, 41.79, and 32.25 µm, and for the HEDP group were 20.25, 16.40, and 15.96 µm, respectively. HEDP seems to have a significantly less erosive effect. Different irrigation protocols with harsher conditions, as might be the case during endodontic retreatment, could be assessed with micro-CT.

A Point-of-Care Digital Workflow for 3D Printed Passive Presurgical Orthopedic Plates in Cleft Care.

Cleft lip and palate are one of the most common congenital craniofacial malformations. As an initial treatment, presurgical orthopedics is considered standard treatment at many cleft centers. Digital impressions are becoming feasible in cleft care. Computer-aided design (CAD) and three-dimensional (3D) printing are manufacturing standards in dentistry. The assimilation of these technologies has the potential to alter the traditional workflow for the fabrication of customized presurgical orthopedic plates. We present a digital workflow comprising three steps: 3D digital image acquisition with an intraoral scanner, open-source CAD modeling, and point-of-care 3D printing for the fabrication of personalized passive presurgical plates for newborns with cleft lip and palate. The digital workflow resulted in patient-related benefits, such as no risk of airway obstruction with quicker data acquisition (range 1-2.5 min). Throughput time was higher in the digital workflow 260-350 min compared to 135 min in the conventional workflow. The manual and personal intervention time was reduced from 135 min to 60 min. We show a clinically useful digital workflow for presurgical plates in cleft treatment. Once care providers overcome procurement costs, digital impressions, and point-of-care 3D printing will simplify these workflows and have the potential to become standard for cleft care.

Micro-Computed Tomographic Assessment of Microcrack Formation before and after Instrumentation of Curved Root Canals with Neoniti Rotary Files.

The aim of this study was to assess the microcrack formation of moderately and severely curved root canals following instrumentation with Neoniti rotary files using micro-computed tomography. This in vitro study evaluated 18 extracted sound mandibular molars with two separate mesial canals and foramina in two groups (n = 9) with 5−20° (moderate) and 20−40° (severe) root canal curvature. The number of microcracks in the root canal walls was counted at baseline by micro-CT. Subsequently, the root canals were instrumented with 0.20/0.06 v Neoniti files as single files with a torque of 1.5 Ncm and a speed of 400 rpm. The number of microcracks was counted again postoperatively on micro-CT images using Amira software. Statistical analysis was performed using the Shapiro−Wilk test, Levene's test and repeated-measures ANOVA (α = 0.05). The mean number of microcracks significantly increased postoperatively in both the moderately curved (11.59 ± 9.74 vs. 8.2 ± 7.4; p = 0.001) and the severely curved (13.23 ± 5.64 vs. 7.20 ± 5.94; p < 0.001) groups. However, the differences between the two groups were not significant (p = 0.668). Based on the results obtained, it can be stated that the instrumentation of moderately and severely curved root canals with Neoniti rotary files increases the number of microcracks. However, the higher degree of curvature does not necessarily translate to a higher number of microcracks after root canal instrumentation with this specific rotary system and methodological procedures.

Comparison of MTA, CEM Cement, and Biodentine as Coronal Plug during Internal Bleaching: An In Vitro Study.

BACKGROUND: Internal bleaching is a choice of treatment in discolored endodontically treated teeth. Cervical root resorption is one of the important complications of this treatment. A suggested procedure to prevent this type of resorption is using a coronal barrier under the bleaching materials. The aim of the study was to compare the microleakage of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, and Biodentine. MATERIALS AND METHODS: In this in vitro study, a total of 60 single canal incisors were included. They were randomly divided into three experimental groups (n = 16), one positive control group (n = 6), and one negative control group (n = 6). Coronal portion of the canals in the experimental groups was sealed with 3 mm of MTA, CEM cement, or Biodentine as a coronal barrier. After 3 days, specimens were bleached. A fresh Enterococcus faecalis suspension was added to the samples. The culture tubes were observed for 45 days, and the daily turbidity was recorded. Statistical analysis was accomplished by the Kaplan-Meier test and SPSS 22. RESULTS: All positive samples showed turbidity, whereas none of the negative samples allowed bacterial leakage. Results showed no significant difference between MTA, CEM cement, and Biodentine groups. (P value = 0.304, 0.695, and 0.217). The bacterial microleakage for the two groups also did not show significant differences. CONCLUSIONS: CEM cement and Biodentine showed promising results as coronal plug, and clinical studies are needed to test these materials with MTA for avoiding microleakage in internal bleaching treatment.

In vitro comparison of shear bond strength of a flowable composite resin and a single-component glass-ionomer to three different pulp-capping agents.

BACKGROUND: Various materials are used for vital pulp capping and the bond strength of restorative materials to these pulp-capping agents significantly affects the success rate of vital pulp therapy. OBJECTIVES: The aim of this study was to determine the shear bond strength of a flowable composite resin and a single-component glass-ionomer to mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement and BiodentineTM as pulp-capping agents. MATERIAL AND METHODS: Seventy-two cylindrical acrylic resin blocks, with a central hole 4 mm × 2 mm, were prepared. Mineral trioxide aggregate, CEM cement and Biodentine were placed in the cavities (n = 24 in each group) and incubated for 24 h. The blocks were subdivided into the composite resin and glassionomer subgroups. Cylindrical plastic molds, measuring 3 mm in height and diameter, were used to place the restorative materials on the samples. The shear bond strength test was performed at a strain rate of 1 mm/min in a universal testing machine. The samples were evaluated under a stereomicroscope at ×25 magnification for fracture modes. The data was analyzed with the one-way analysis of variance (ANOVA) and Tukey tests. RESULTS: The maximum and minimum mean shear bond strength values were recorded in the Biodentinecomposite resin (4.77 MPa) and MTA-glass-ionomer (2.20 MPa) groups, respectively. There were significant differences in the mean shear bond strength values of MTA, CEM cement and Biodentine to the composite resin and glass-ionomer (p < 0.001). CONCLUSIONS: A composite material may be preferable for definitive filling after pulp capping with Biodentine.

Clinical Outcomes of Low-level Laser Therapy in Management of Advanced Implant Surgery Complications: A Comparative Clinical Study.

INTRODUCTION: Nowadays, implant insertion is accompanied by undesired consequences. As surgery techniques become more and more complex, an increase of intra- and post-op complications can be expected. Application of low-level laser (LLL) is one of the conservative approaches to control the complications with any side effects and low treatment costs. The present study aimed to evaluate the effect of 650 nm LLL irradiation on the reduction of complications after advanced implant surgeries. MATERIALS AND METHODS: In this triple-blinded clinical trial, 30 patients aged between 25 to 65 years were in need of bone graft or sinus lift procedure for simultaneously implant insertion. In the LLL treatment group, the surgical site of each implant was treated with 650 nm laser. The same method and duration were applied in the placebo group. The pain levels, facial swelling, and wound healing were evaluated. RESULTS: This study indicated that pain levels were reduced in the laser group (p <0.05). Also, facial swelling in the 3rd and 7th day after the surgery relieved more in laser group. Furthermore, investigation of the surgical site showed a higher level of wound healing in the laser group (p <0.05). CONCLUSION: Regarding the biological effects of advanced implant surgeries and accompanying complications, adjuvant treatment with a laser could significantly improve wound healing and reduce the severity and duration of pain and swelling. CLINICAL SIGNIFICANCE: This clinical trial demonstrates reductions of the level of pain, facial swelling and improvements of wound healing are followed by the use of low-level laser therapy.

Comparative evaluation of Enterococcus faecalis counts in different tapers of rotary system and irrigation fluids: An ex vivo study.

BACKGROUND: Bacteria and their by-products are etiological factors for the failure of endodontic treatment. Reduction of root canal bacterial contamination is one of the chief aims of root canal therapy. The aim of this study was to compare the effects of different rotary file tapers and two irrigation fluids on Enterococcus faecalis counts. MATERIALS AND METHODS: In this ex vivo study Root canals of 72 human upper lateral incisors were enlarged to ISO #20 K-file. Then, the samples were sterilized and inoculated with E. faecalis for 72 h, divided into six experimental groups and prepared with #30 Flexmaster files with 0.02, 0.04, and 0.06 tapers and two different irrigation solutions such as normal saline and sodium hypochlorite. The control group (n = 10) was subdivided into two groups with or without bacterial inoculation and no mechanical instrumentation. Cleaning efficacy was evaluated in terms of the reduction of colony forming units (CFUs). T-test, ANOVA, Duncan, and Tukey tests were applied to the groups. A significant level of α = 0.05 was set for comparison between the groups. RESULTS: The canals instrumented with 0.06 taper exhibited greater significant reduction in CFUs compared to canals instrumented with 0.04 and 0.02 taper (P < 0.05); 0.04 taper also resulted in greater significant reduction in CFUs than 0.02 taper (P < 0.05). In addition, no significant differences were observed in E. faecalis counts between the two irrigation fluids (P > 0.05). CONCLUSION: Under the conditions of this study, root canal preparation with greater taper resulted in canal cleanliness and better debridement.

Adherence to confidentiality principles from the viewpoint of Iranian dental students: A multicenter study.

INTRODUCTION: Confidentiality is a basic ethical principle appreciating human autonomy, relationships, and dignity and in medical research has a long history. In dental practice, it has the same importance as medical field. Therefore, providing patients with information about the confidentiality will promote their confidence in dental professionals and prevent legal conflicts. The present study sought to evaluate the knowledge and viewpoints of dental students about patient confidentiality. METHODS AND MATERIALS: In this multicenter applied research, the participants were recruited from schools of dentistry of Isfahan, Tehran, Tabriz, Shiraz, and Mashhad Universities of Medical Sciences and Isfahan Islamic Azad University during 2013. Ultimately, data were collected randomly with a researcher-made questionnaire from 180 dental students of fifth-sixth-year. The collected data were entered into SPSS 20.0. Independent t-tests and one-way analysis of variance (ANOVA) were performed to analyze the data. RESULT: Overall, 60.3% of the participating students were concerned about acquiring adequate knowledge on the concept of patient confidentiality and 59.0% felt obliged to participate in related educational courses. Most students (66.5%) were careful not to share patient information with their friends. According to one-way ANOVA, students of Tehran University of Medical Sciences scored significantly higher than other participants. However, no significant differences were detected between the students of other schools. CONCLUSION: The confidentiality laws imposed by the Ministry of Health and Medical Education seem to adequate details, but needs more education for dentists. Also it should be accentuated, due to state of confidentiality in patients' rights guidline and courses on ethics should be tailored based on the specific subjects raised in each field of dentistry.