Radiographic patterns of periosteal bone reactions associated with endodontic lesions.

Objectives: The formation of new bone by periosteum due to an insult is called periosteal bone reaction (PBR). This study assessed the cone beam computed tomography (CBCT) patterns of periosteal bone reactions associated with periapical inflammatory lesion (apical periodontitis/periapical rarefying osteitis). Materials and Methods: Twenty-two small field of view CBCT images of patients with PBR were selected from a database of a private practice limited to endodontics. The volume of the periapical inflammatory lesion, the presence of cortical fenestration, the distance of the root apices to the affected cortex, and the location, pattern, and longest diameter of the periosteal reaction were recorded. Statistical analysis was performed using Wilcoxon Ranksum, Fischer's exact, Spearman Correlation Coefficient, and paired t-test. Results: In all cases, periosteal bone reaction manifested as either parallel (90.9%) or irregular (9.1%). No correlation was found between periapical inflammatory lesion volume and the periosteal reaction's longest diameter (p > 0.05). Cortical fenestration was noted in 72.7% of the cases. In addition, the findings showed that periosteal reactions were located mostly on the buccal and were present 53.8% and 100% of the time in the mandible and maxilla, respectively. Conclusions: The periosteal reactions of endodontic origin had a nonaggressive form (i.e., parallel or irregular), and none of the lesions resulted in a periosteal reaction with an ominous Codman's triangle or spicule pattern.

Evaluation of Cone-beam Computed Tomography Artifacts Produced by Metal Objects Located Within and Outside the Field of View.

INTRODUCTION: Artifacts created by the presence of metal objects in the jaw negatively affect the cone-beam computed tomographic image quality. This study compares artifacts produced by metal objects outside of the field of view (FOV) in a small FOV CBCT image with those produced in a large FOV image in which the metal object is within the FOV. METHODS: We methodically placed 4 titanium implant-sized rods and 4 zirconium crown-sized disks on 1 side of a human cadaver mandible. Using the Accuitomo 170 CBCT machine (J Morita, Irvine, CA), a total of 18 scans (9 with a small FOV and 9 with a large FOV) were made. Ten axial slices from each scan were transferred to ImageJ software (National Institutes of Health, Bethesda, MD) for analysis. The mean standard deviation of all voxel values of a fixed region of interest (ie, uniform air located lingual to tooth #30) was compared between small and large FOV slices. Two blinded observers subjectively rated the images for diagnostic quality and the presence of artifacts. RESULTS: The Wilcoxon signed rank test showed that the standard deviation for both small and large FOV slices increases as the number of metal objects increases. The mean of the standard deviation for small and large FOVs is 3.6 and 2.5, respectively (P = .0000). Fifty-three percent of the small FOV slices had more artifacts in the subjective analysis. One hundred percent of the small FOV slices were rated as higher quality. CONCLUSION: Metal objects outside of the FOV in the contralateral quadrant do affect the quality of small FOV images. However, small FOV images have a higher resolution compared with large FOV images.

Comparing dentinal tubule penetration of conventional and 'HiFlow' bioceramic sealers with resin-based sealer: An in vitro study.

This study compared the depth and percentage of dentinal tubule penetration for single-cone (SC) and warm vertical (WV) obturation techniques with two different bioceramic sealers (BC Sealer [BCS], BC Sealer HiFlow [BCSHF]) and an epoxy resin-based sealer (2Seal easymiX). Fifty canals were filled with BCS, BCSHF or resin-based sealer (RBS). Teeth in BCS and BCSHF groups were filled with SC or WV techniques, and teeth in the control group (RBS) filled with WV technique only. The roots were sectioned at 3 mm and 6 mm levels from the apex and evaluated with a confocal laser microscope. There was significantly greater depth and percentage of sealer penetration at the 6 mm section compared to 3 mm (P < 0.05). No statistically significant difference was found in sealer type or obturation technique at the examined levels (P > 0.05). In conclusion, dentinal tubule penetration was similar comparing BC Sealer, BC Sealer HiFlow and RBS using SC and WV techniques.

Retrograde Instrumentation of Surgically Resected Roots Using Controlled Memory Files: A Human Cadaver Study.

INTRODUCTION: The purpose of this study is to evaluate the amount of residual obturation material of retroinstrumented surgically resected roots using controlled memory files and to evaluate the incidence of adverse treatment outcomes. METHODS: Thirty maxillary anterior teeth in human cadavers were selected, and nonsurgical root canal treatment was performed on these teeth. A standardized 4-mm osteotomy and a 3-mm root resection with as close to 0° bevel as possible were made on each tooth. A microsurgical diamond tip was used to create a 1- to 2-mm starting point for each retropreparation. A 25/06 and 30/06 VTaper 2H were bent at about 90° angle to mimic the clinical and anatomic restrictions and used to create a retropreparation to a depth of 14 mm. Micro-computed tomography scans were taken and analyzed for volume and percentage of residual obturation material at 5 and 10 mm. In addition, the incidences of instrument separation and crack and ledge formation in the teeth were recorded. RESULTS: The median volume of residual obturation at 5 and 10 mm was 0.18 mm3 (interquartile range, 0.36 mm3) and 1.97 mm3 (interquartile range, 1.99 mm3), respectively. The overall incidence of file separation during retropreparation was 13.33% (4/30). Among the cases analyzed with micro-computed tomography, none showed crack or ledge formation. CONCLUSIONS: Retroinstrumentation of surgically resected roots using controlled memory files cleans the canal effectively with relatively low adverse treatment outcomes. Although this novel technique is limited in application, it is a safe and effective way to achieve a deep, clean retropreparation.

Comparison of a Dental Operating Microscope and High-resolution Videoscope for Endodontic Procedures.

INTRODUCTION: The purpose of this study was to compare a dental operating microscope (DOM) with a high-resolution videoscope (VS) in terms of depth of field (DOF), resolution, and effect on fine motor skills. METHODS: Two observers used test targets to measure the resolution and DOF of the DOM and the VS. In addition, 18 participants (12 dental students and 6 endodontic residents) performed an accuracy test on a manikin head using DOM, VS, or loupes. Each participant completed a posttest survey. RESULTS: The 3 magnifications of the DOM had higher resolutions and DOF (resolution: 32, 40.3, and 50.8 line pairs/mm; DOF: 15, 10, and 6 mm) than the VS (resolution: 20.1 line pairs/mm; DOF: 5 mm). Accuracy testing showed the DOM produced better results than the VS for both resident and student groups (P < .001); however, the VS was not significantly different than loupes. The residents performed better than the students using the DOM and the VS (P < .001). The students in general took 1.3 times longer than the residents to perform the accuracy test, irrespective of the magnification device used. The DOM and the VS required on average 1.9 and 2.8 times longer compared with loupes, respectively. Most participants reported a preference for the DOM with regard to visualization and ease of use. Comments also suggested that the VS has value in diagnosis and magnification in endodontics. CONCLUSIONS: Considering the findings from this study, the DOM stands out as the leading magnification tool in endodontics. However, the VS has potential in endodontic procedures and might be used as an adjunct to other visualization aids.

Periradicular Lesions in Cancellous Bone Can Be Detected Radiographically.

INTRODUCTION: The purpose of this study was to evaluate whether naturally occurring periradicular lesions confined to cancellous bone can be detected on periapical digital radiography and whether the size of the lesion had any effect on lesion detection. METHODS: One hundred twenty-nine roots were chosen based on cone-beam computed tomographic imaging and categorized as having no lesion, a lesion confined to cancellous bone, a lesion that encroaches on junctional corticocancellous trabeculae, or a lesion with cortical involvement. The largest buccolingual dimension of the lesions was measured on cone-beam computed tomographic imaging. Two observers separately viewed the corresponding periapical radiographs in their original version as well as in the edge-enhanced setting on MiPACS (LEAD Technologies Inc, Charlotte, NC). Observers were asked to evaluate and interpret the periapical radiographs as having a lesion present, absent, or "unsure." Evaluations of images were conducted at 2 times 1 week apart. Data were analyzed, and the level of significance was set at P = .05. RESULTS: Lesion size, not the degree of cortical involvement, significantly affected the observers' ability to accurately detect lesions. As the size of the lesion increased, the probability of correctly identifying a lesion increased (P = .0008). Lesions were correctly identified 97.6%, 94.1%, 91.6%, and 89.3% of the time, respectively, when in cortical bone, at the junction of corticocancellous bone, in cancellous bone, and when no lesion was present. Observers were "unsure" whether a lesion was present or absent 10.7% of the time. Only lesions in cortical bone significantly increased observers' certainty in making a diagnosis. CONCLUSIONS: This study concluded that lesions confined to cancellous bone can be detected radiographically at a high rate. Lesion size was positively correlated with correct lesion identification, whereas the degree of cortical involvement had no significant effect. This suggests that lesion size may be a better predictor for correct lesion identification than lesion location.

Dynamics of Bone Loss in Cases with Acute or Chronic Apical Abscess.

INTRODUCTION: Acute and chronic apical abscesses are 2 dramatic ways that periradicular tissues may react to pulpal infection and necrosis. Although both of these clinical states are the response to pulpal infection, their clinical manifestations are significantly different. It is not clear why the body responds to root canal infection in one way or another. The objective of this study was to evaluate the size and pattern of bone loss in patients with acute apical abscess (AAA) and chronic apical abscess (CAA) using cone-beam computed tomographic images. METHODS: Twenty-three cone-beam computed tomographic images of cases with AAA and 25 cases with CAA were selected and evaluated. The presence and location of fenestration and the volume and pattern of the periradicular lesions were recorded and compared between the 2 groups using the Fisher exact and Mann-Whitney U tests. RESULTS: One hundred percent of cases with CAA had cortical fenestration, but only 47% of cases with AAA had cortical fenestration (P < .05). The median volume of the lesions was 233 mm3 in the CAA group and 109 mm3 in the AAA group (P > .05). CAA cases, in comparison with the AAA group, had a relatively larger cortical disruptions. CONCLUSIONS: Cortical fenestration is fundamental for the development of CAA. However, periradicular lesions without evident cortical fenestration can still cause AAA and fascial space involvement.

Resveratrol represses tumor necrosis factor α/c-Jun N-terminal kinase signaling via autophagy in human dental pulp stem cells.

OBJECTIVES: To study the effects of polyphenol resveratrol on TNFα-induced inflammatory signaling as well as the underlying mechanism in human dental pulp stem cells (DPSCs). MATERIALS AND METHODS: Human DPSCs were cultured and treated by TNFα in the presence or absence of resveratrol. NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways were analyzed by Western blotting and immunofluorescence staining. Interleukin 6 (IL6) and interleukin 8 (IL8) mRNA levels were analyzed by reverse transcription polymerase chain reaction. For the mechanistic study, autophagy was examined and further manipulated by gene silencing of Atg5 using siRNAs. Statistical analysis was performed by Student's t- test, and values of p < 0.05 were considered significant. RESULTS: Upon TNFα treatments, neither degradation of IκBα nor the phosphorylation and nuclear translocation of p65 NF-κB were inhibited by resveratrol at different concentrations. In contrast, resveratrol dramatically inhibited TNFα-induced phosphorylation of c-Jun N-terminal kinase (JNK) MAPK. Furthermore, resveratrol activated autophagy, as evidenced by the accumulated autophagic puncta formed by lipid bound LC3B in resveratrol-treated cells. Intriguingly, both resveratrol and JNK inhibitor SP600125 suppressed TNFα-induced IL6 and IL8 mRNA expression (P < 0.05). Silencing autophagy gene Atg5 led to the hyper-activation of JNK and augmented TNFα-induced IL6 and IL8 mRNA expression (P < 0.05). CONCLUSIONS: The results suggest that resveratrol suppresses TNFα-induced inflammatory cytokines expressed by DPSCs through regulating the inhibitory autophagy-JNK signaling cascade. Resveratrol might be beneficial to ameliorate pulpal damage during the acute phase of inflammation in vital pulp therapy.