The Radiopacity of 29 Resin Restorative Materials Compared to Enamel

The radiodensity of a composite resin can greatly influence a clinician\u27s ability to analyze a restoration for failure. The purpose of this study was to determine the relative radiopacities of 29 resin restorative materials compared to enamel, and to verify the comparable radiopacity between shades of 23 of the restorative composite resin materials. Composite resin discs measuring \u3e5mm in diameter and 2 mm in thickness were made and polymerized. Radiographs were taken of the composite resin discs, which included an aluminum step wedge for calibration and a densitometer was used to measure the radiodensity of the composite resin samples. The coefficient of variation was calculated for the data and a Wilcoxon-Rank Sum test was performed showing that all the composite resin samples were significantly different in radiodensity from the enamel control (p \u3c .0001). In 19 of the 23 pairs of composite resins (83%) there was no statically significant difference in radiodensity. The coefficient of variation ranged from 0.86% to 3.54% for the data collected. 26 of the 29 composite resin resins were more radiopaque than enamel, and 21 of the 29 had a density value of less than 0.90 D which is approximately 0.1 D less than enamel. A density value less than enamel facilitates clinicians in the diagnosis of recurrent caries, defects, and overhangs in composite resin restorations

In Vitro Antimicrobial Efficacy of Calcium Hydroxides in Root Dentin

Enterococcus faecalis is the most commonly isolated bacteria in failed root canal treatment. Endodontic intracanal medicaments are commonly tested using standardized bovine cylinders infected with bacteria. The literature is not clear on whether calcium hydroxides are able to remove E. faecalis from the dentinal tubules. One reason for this is that there are several varying forms of calcium hydroxide commonly used. The purpose of the present experiment was to determine whether four commonly used calcium hydroxide products were able to reduce E. faecalis from four incremental samples of dentin and to determine if there was a statistically significant difference between each medicament in its ability to eliminate E. faecalis from bovine dentinal tubules. Ninety freshly extracted incisors from 22-24 month old cows were milled into standardized cylinders of the following dimension: 5 mm high, external diameter of 7 mm, and lumen diameter of 2.7 mm. The cylinders were sterilized and were all subsequently infected with Enterococcus faecalis ATCC4082, except for 15 which were set aside as negative controls. The remaining cylinders were divided into four treatment groups of 15 and a positive control group also consisting of 15 cylinders. The four treatment groups had the canal lumen filled with Calasept®, Diapex®, Ultracal®, or Pulpdent® for two weeks. After two weeks, round burs sized ISO 029, 031, 033, and 035 were passed through the lumens, dentin shavings were weighed, cultured and CFU/mg were enumerated. One-way ANOVA, Student-Newman-Keuls multiple comparison procedure, and Kruskal-Wallace tests were used for data analysis. Statistically significant reductions in CFU/mg E. faecalis were found between the four treatment groups and the positive controls (p \u3c 0.0001). Reductions in CFU/mg E. faecalis of 94.1%-100.0% were observed. There was no statistically significant difference between the medicaments. All p-values were \u3e 0.5

Clinical guidelines for treating caries in adults following a minimal intervention policy?Evidence and consensus based report

Objectives: In 2002, FDI (World Dental Federation) published a policy advocating that caries be treated by minimal intervention (MI). This MI policy has been accepted worldwide and is taught in universities. But acceptance in general dental practice has been slower, especially in Japan where healthcare payment and practice favour drilling and filling. To help disseminate this MI policy into general practice, the Japanese Society of Conservative Dentistry developed an evidence-based clinical guideline for restoring carious permanent teeth in adult patients. Methods: The guideline was developed by a committee of nine university clinicians and a librarian. The committee selected the most frequent clinical questions in treating caries and used electronic databases to search and assess the best scientific evidence for each. Members then added their clinical experience and discussed to reach consensus on each question on treating caries with MI policy. Graded recommendations and guidance were made for each clinical question. The provisional guideline was strengthened after review and discussion with university researchers and general practitioners. Results: The guideline addresses the 16 most frequent clinical questions in treating adult caries, including restorative methods and how to tackle root caries. Recommendations for treatment using MI policy were developed using the best scientific evidence and consensus of experienced clinicians. Clinical significance: The guideline offers a practical expert view of treating caries with the MI policy that incorporates the best scientific evidence, the latest techniques, the most preferable materials and the general consensus of expert clinicians

New occurrences of mammals from McKay Reservoir (Hemphillian, Oregon)

12 pagesEncompassing global cooling, the spread of grasslands, and biogeographic interchanges, the Hemphillian North American Land Mammal Age is an important interval for understanding the factors driving ecological and evolutionary change through time. McKay Reservoir near Pendleton, Oregon is a natural laboratory for analyses of these factors. It is remarkable for its small vertebrate fauna including rodents, bats, turtles, and lagomorphs, but also for its larger mammal fossils like camelids, rhinocerotids, canids, and felids. Despite the importance of the site, few revisions to its faunal list have been published since its original description. We expand on this description by identifying taxa not previously known from McKay Reservoir based on specimens collected during fieldwork and through reidentification of previously collected fossils. Newly identified taxa include the borophagine canid Borophagus secundus (Matthew and Cook, 1909), the camelids Megatylopus Matthew and Cook, 1909 and Pleiolama Webb and Meachen, 2004, a dromomerycid, and the equids Cormohipparion Skinner and MacFadden, 1977 and Pseudhipparion Ameghino, 1904. Specimens previously assigned to Neohipparion Gidley, 1903 and Hipparion de Christol, 1832 lack the features necessary to diagnose these genera, which are therefore removed from the site's faunal list. The presence of Borophagus secundus, Cormohipparion, and Pseudhipparion is especially important, because each occurrence represents a major geographic range extension. This refined understanding of the fauna lays the foundation for future studies of taphonomy, taxonomy, functional morphology, and paleoecology—potentially at the population, community, or ecosystem levels—at this paleobiologically significant Miocene locality