Effect of Mandibular Angulation on Pre-Implant Site Measurement Accuracy Using CBCT.

PURPOSE: To evaluate the accuracy of available bone width, height, and length measurements on pre-planned implant sites using CBCT images scanned at different angulations of the mandible. MATERIALS AND METHODS: Standard cylindrical holes were prepared on six dry human mandibles and filled with warm gutta-percha to create spherical markers for measurements of available bone width, height, and length. Mandibles were first scanned with a CBCT device in an ideal position with the occlusal plane parallel to the horizontal plane. Then, images of the mandibles were obtained in rotation, tilt, flexion, and extension positions using 5- and 10-degree angulations. Measurements were done on a total of 54 images. Original dimensions of the available bone for planned implant sites were measured with a digital caliper on dry mandibles as the gold standard. The absolute values of the differences between each measurement and the gold standard were obtained for measurement errors. Repeated-measures analysis of variance and Dunnett's multiple comparisons test were used for comparisons (P = .05). Intraobserver and interobserver agreement was calculated using intraclass correlation coefficient (ICC). RESULTS: ICC was excellent for both intraobserver and interobserver reproducibility. No significant difference was found between length and height measurements in ideal position and in rotation, tilt, flexion, and extension movements of mandibles at two different angulations (P > .05). Width measurements revealed a significant difference among ideal measurements and measurements at 10-degree flexion, 10-degree extension, 10-degree rotation, and 10-degree tilted mandibular positions (P < .05). CONCLUSION: The position of the occlusal plane with respect to the floor during the CBCT scan may have a clinically significant effect on dental implant site dimensions.

European Society of Endodontology position statement: the use of antibiotics in endodontics.

This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on Antibiotics in Endodontics. The statement is based on current scientific evidence as well as the expertise of the committee. The goal is to provide dentists and other healthcare workers with evidence-based criteria for when to use antibiotics in the treatment of endodontic infections, traumatic injuries of the teeth, revascularization procedures in immature teeth with pulp necrosis, and in prophylaxis for medically compromised patients. It also highlights the role that dentists and others can play in preventing the overuse of antibiotics. A recent review article provides the basis for this position statement and more detailed background information (International Endodontic Journal, 2017, https://doi.org/10.1111/iej.12741). Given the dynamic nature of research in this area, this position statement will be updated at appropriate intervals.

Antibiotics in Endodontics: a review.

The overuse of antibiotics and the emergence of antibiotic-resistant bacterial strains is a global concern. This concern is also of importance in terms of the oral microbiota and the use of antibiotics to deal with oral and dental infections. The aim of this paper was to review the current literature on the indications and use of antibiotics and to make recommendations for their prescription in endodontic patients. Odontogenic infections, including endodontic infections, are polymicrobial, and in most cases, the prescription of antibiotics is empirical. This has led to the increasing use of broad-spectrum antibiotics even in cases where antibiotics are not indicated, such as symptomatic irreversible pulpitis, necrotic pulps and localized acute apical abscesses. In case of discrete and localized swelling, the primary aim is to achieve drainage without additional antibiotics. Adjunctive antibiotic treatment may be necessary in the prevention of the spread of infection, in acute apical abscesses with systemic involvement and in progressive and persistent infections. Medically compromised patients are more susceptible to complication arising from odontogenic infections and antimicrobials have a more specific role in their treatment. Therefore, antibiotics should be considered in patients having systemic diseases with compromised immunity or in patients with a localized congenital or acquired altered defence capacity, such as patients with infective endocarditis, prosthetic cardiac valves or recent prosthetic joint replacement. Penicillin VK, possibly combined with metronidazole to cover anaerobic strains, is still effective in most cases. However, amoxicillin (alone or together with clavulanic acid) is recommended because of better absorption and lower risk of side effects. In case of confirmed penicillin allergy, lincosamides such as clindamycin are the drug of choice.

Pixel intensity and fractal dimension of periapical lesions visually indiscernible in radiographs.

INTRODUCTION: The purpose of the study was to analyze pixel intensity (PI) and fractal dimension (FD) values in radiographs of chemically created but visually undetectable periapical lesions. METHODS: Artificial lesions were created by applying 70% perchloric acid to the sockets of left and right first premolars in 12 cadaver mandibles. For preparation of relatively small lesions, the acid was applied for 30 and 60 minutes. Before and after each acid application, radiographs were taken (60 kVp, 7 mA, and 1.5 mm Al equivalent filtration for 0.12 second) with storage phosphor plates. An optical bench was used to standardize projection geometry. Image plates were scanned immediately after exposure, and the acquired images were saved uncompressed in TIF format. Six observers evaluated the images by using a 5-grade scale, and the images scored as "definitely absent" by all observers were used for the calculations of PI and FD. Box-counting FDs and differences in mean PI were computed for regions of interest at the apical areas of each premolar. Repeated-measures analysis of variance, Tukey test, and Pearson correlation coefficient test were used for statistical analysis. RESULTS: A significant difference was found in FD values after both acid application periods (P < .05), whereas a difference in PI was detected only in images obtained after 60-minute acid application (P < .05). There was a negative correlation between FD and PI values (-0.754, P < .05). CONCLUSIONS: Calculation of FD can be a tool for the early detection of periapical lesions given the presence of baseline radiographs.

Diagnostic accuracy of Digora Optime storage phosphor plates for proximal subsurface demineralization: effect of different exposure times.

OBJECTIVE: The aim of this study was to compare the diagnostic accuracy of F-speed film and storage phosphor plate (SPP) exposed with different exposure times for the detection of artificial enamel subsurface demineralization. STUDY DESIGN: Standard enamel windows of extracted premolars were exposed to a demineralizing solution. All teeth were radiographed before and after acid application with F-speed films and SPPs. Films were exposed for 0.25 seconds and SPPs were exposed using 4 exposure times. Receiver operating characteristic analysis was used for diagnostic accuracy (A(z)). RESULTS: Significant differences were obtained among A(z)s of 0.08- versus 0.12-seconds and 0.10- versus 0.12-second exposed SPPs (P < .05). A(z)s of films were higher than the SPPs exposed with 0.08, 0.10, and 0.12 seconds (P < .05). No difference was found between the A(z)s of the 2 systems when SPPs were exposed for 0.16 seconds (P > .05). CONCLUSIONS: Diagnostic accuracy of films and SPPs was not impaired when exposure time was 36% reduced for the latter; however, diagnosis was impaired when reduced 52%.

Random/aligned electrospun PCL/PCL-collagen nanofibrous membranes: comparison of neural differentiation of rat AdMSCs and BMSCs.

In this study, the aligned (A) and randomly oriented (R) polycaprolactone (PCL-A and PCL-R) and PCL/collagen (PCL/Col-A and PCL/Col-R) nanofibers were electrospun onto smooth PCL membranes (PCLMs) prepared by solvent casting. In order to investigate the effects of chemical composition and nanotopography of fibrous surfaces on proliferation and on neural differentiation of mesenchymal stem cells (MSCs), adipose and bone marrow-derived rat MSCs (AdMSCs and BMSCs) were cultivated in suitable media i.e. inducing medium containing basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF), and cell maintenance medium (CMM). BMSCs adhered and proliferated on all nanofibrous membranes more efficiently than AdMSCs. PCL/Col-A was found as the most convenient surface supporting proliferation in both cell types. Immunofluorescence staining indicated that BMSCs and AdMSCs are prone for differentiation to oligodendrocytes more than they differentiate to other neuronal cell types. PCL-A nanofibrous membranes supported differentiation of MSCs to O4(+) (an oligodendrocytes surface antigen) cells in both culture media. The intensity of immunoreactivity of O4(+) cells differentiated from BMSCs on PCL-A was highest when compared with the other groups (p < 0.001). Some BIII-T signed neural cells were investigated on PCL-A nanofibrous membranes, but the intensity of immunoreactivity was lower than that of O4(+) cells. In conclusion, this study can be evaluated to establish the cell therapy strategies in neurodegenerative disorders, which are relevant to oligodendrocyte abstinence using BMSCs or AdMSCs on aligned nanofibrous membranes.

Differences in aluminum equivalent values of endodontic sealers: conventional versus digital radiography.

The aims of this study were to compare film and digital radiography in assessing the radiopacities of root canal sealers and to establish the relation in aluminum equivalent values of different methods. Standard disks of 5 different sealers were exposed together with an aluminum step wedge by using occlusal films and storage phosphor plates. Optical density of the sealers was evaluated by transmission densitometry, and mean gray values were determined by digital analysis. The data were analyzed by using two-way analysis of variance (P = .05). Pairwise comparisons were made by using Tukey post hoc and paired t tests (P = .05). The order from the most radiopaque to the most radiolucent sealer was the same for both methods; however, aluminum equivalent values determined by transmission densitometry were significantly higher (P < .01). Aluminum equivalent values of the 2 radiographic methods were 7%-20% different. The International Standards Organization standard for the radiopacity of dental root canal sealing materials needs modifications for digital systems.

Prevalence of Candida albicans in oral cavities and root canals of children.

The aim of this study was to examine the prevalence of C. albicans in the oral cavities and root canals of children. Twenty healthy and caries-free children and 13 children with caries, were screened. Imprint samples and sterile paper points were used to obtain the samples from oral cavities and root canals respectively. The production of germ tubes and the development of chlamydospores identified yeast cultures. Sixty-nine percent of children with caries and 5% of caries-free children were found to be Candida carriers. The difference in candidal prevalence between two groups was significant (p < 0.05). Sixty-one point five percent of children were positive for Candida in the root canal. Since, increase in the C. albicans in the oral cavity provides a potential source of the fungus particularly when resistance falls below a certain threshold, attention to strategies for the reduction of this pervasive and persistent pathogen becomes important. Therefore, reduction of caries and or introduction of antifungal agents during root canal treatment of children may be offered.