Comparison of the accuracy of CBCT effective radiation dose information in peer-reviewed journals and dental media

Accessible sources of clinical information have proliferated over the past decade. Although these new sources that contextualize information for practice are user friendly, there are questions about their accuracy because much of the material is not peer reviewed. On the other hand, traditional peer-reviewed material can be somewhat removed from the needs of practicing dentists, and recently questions have been raised about the accuracy of journals. This study assessed the accuracy of cone beam computed tomography (CBCT) radiation safety information in both professional media and peer-reviewed journals. Articles introducing CBCT technology to dentists and published in peer-reviewed journals were compared to articles appearing in professional magazines, clinically oriented news sites, and blogs written by clinicians for clinicians. The reported radiation doses of CBCT and conventional dental radiographs were recorded, as were conclusions about the comparative doses of these 2 imaging modalities. The proportion of articles reporting CBCT dose to be greater than, equal to, or less than that of conventional dental radiographs was not different between the peer-reviewed and professional media articles during the period 2003-2016. There is weak evidence that the conclusions of peer-reviewed journal articles, but not professional media sources, became more conservative after the 2010 publication of an article in The New York Times that was critical of misinformation concerning the safety and efficacy of CBCT in dentistry. Professional media articles that were not peer reviewed were as accurate as peer-reviewed journals for this topic and during the time period assessed. However, the method used here necessitated a narrow focus, and more studies are needed to broaden understanding.

Associations of types of pain with crack-level, tooth-level and patient-level characteristics in posterior teeth with visible cracks: Findings from the National Dental Practice-Based Research Network

OBJECTIVES

The objective of this study was to determine which patient traits, behaviors, external tooth and/or crack characteristics correlate with the types of symptoms that teeth with visible cracks exhibit, namely pain on biting, pain due to cold stimuli, or spontaneous pain.

METHODS

Dentists in the National Dental Practice-Based Research Network enrolled a convenience sample of subjects each of whom had a single, vital posterior tooth with at least one observable external crack (cracked teeth); 2858 cracked teeth from 209 practitioners were enrolled. Data were collected at the patient-, tooth-, and crack-level. Generalized estimating equations were used to obtain significant (p < .05) independent odds ratios (OR) associated with teeth that were painful for 10 outcomes based on types of pain and combinations thereof.

RESULTS

Overall, 45% of cracked teeth had one or more symptoms. Pain to cold was the most common symptom, which occurred in 37% of cracked teeth. Pain on biting (16%) and spontaneous pain (11%) were less common. Sixty-five percent of symptomatic cracked teeth had only one type of symptom, of these 78% were painful only to cold. No patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Positive associations for various combinations of pain symptoms were present with cracks that: (1) were on molars; (2) were in occlusion; (3) had a wear facet through enamel; (4) had caries; (5) were evident on a radiograph; (6) ran in more than one direction; (7) blocked transilluminated light; (8) connected with another crack; (9) extended onto the root; (10) extended in more than one direction; or (11) were on the distal surface. Persons who were <65 yo or who clench, grind, or press their teeth together also were more likely to have pain symptoms. Pain was less likely in teeth with stained cracks or exposed roots, or in non-Hispanic whites.

CONCLUSIONS

Although pain to cold was the most commonly noted pain associated with symptomatic cracked teeth, no patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Characteristics were only associated with pain on biting and/or spontaneous pain with or without pain to cold.

CLINICAL SIGNIFICANCE

Although often considered the most reliable diagnosis for a cracked tooth, pain on biting is not the most common symptom of a tooth with a visible crack, but rather pain to cold.

Reorganization of the GABAergic system following brain extirpation in the earthworm (Eisenia fetida, Annelida, Oligochaeta)

The reorganization of the GABAergic system was studied by means of immunohistochemistry after the symmetrical and asymmetrical (unilateral) extirpation of the brain of the annelid Eisenia fetida. GABA-immunoreactive neurons were first observed in the wound tissue on the 3rd postoperative day. Thereafter the number of labelled cells gradually increased, and by postoperative days 76-80 all GABA-immunoreactive cells (approx. 140 neurons) could be found in their final positions in the symmetrically regenerated brain. After asymmetrical brain extirpation, nearly all cells (70-75) could be detected in the regenerating hemisphere by postoperative days 50-56. In the early stages of the asymmetrical regeneration of the brain, more GABAergic cells were concentrated dorsally and laterally in the preganglion than during the symmetrical type of regeneration. In both types of regeneration, the immunoreactive neurons in the regenerated brain originated in part from undifferentiated neuroblasts situated in different parts of the body, and in part from dividing neurons localized mainly in the pharyngeal nerve plexus. Both exogenous GABA and picrotoxin, applied during the early stages (days 10- 12) of brain regeneration, inhibited the development of the wound tissue and the migration of the neuroblasts and the enteric neurons. At the same time, exogenous GABA application accelerated the proliferation of the pharyngeal neurons. No effect on the process of regeneration could be demonstrated when exogenous GABA and picrotoxin were given together.

Distribution and action of some putative neurotransmitters in the stomatogastric nervous system of the earthworm, Eisenia fetida (Oligochaeta, Annelida)

The chemical neuroanatomy of the stomatogastric nervous system of the earthworm, Eisenia fetida, has been investigated, using antibodies raised against serotonin, tyrosine hydroxylase, octopamine, GABA, FMRFamide, proctolin, Eisenia tetradecapeptide and neuropeptide Y. Neurons immunoreactive to these antibodies can be observed in the stomatogastric ganglia. The labelled cells comprise altogether 95.4% of the total number of neurons in the ganglion. Immunoreactive projections were followed between stomatogastric individual ganglia as well as towards the enteric plexus. Intrinsic neurons containing the different signal molecules examined are present along the entire length of the enteric plexus, but serotonin immunoreactive perikarya were only found in the hindgut. The density of the different immunoreactive neurons, except the serotonin ones, is highest in the pharyngeal plexus, and the number of labelled neurons decreases along the alimentary canal towards the hindgut. A number of epithelial cells also reveal tyrosine hydroxylase, octopamine, GABA and Eisenia tetradecapeptide immunoreactivity. The action of some putative neurotransmitters, such as dopamine, octopamine, serotonin and proctolin was tested on foregut preparations. Dopamine and octopamine (10(-6)-10(-4) M) have an excitatory effect on the musculature, whereas the effect of serotonin depends on the actual muscle tension. Following precontraction evoked by acetylcholine, serotonin in low concentrations (10(-7)-10(-6) M) causes relaxation, whereas in higher (10(-4) M) concentration it evokes slight contractions. In preparations at basal tone, serotonin (10(-7)-10(-6) M) evokes contractions of the foregut. Atropine strongly inhibits the action of acetylcholine but is ineffective against serotonin, dopamine and octopamine. Similarly, the Na+ channel blocker tetrodotoxin fails to influence the contractile effect of dopamine, octopamine and serotonin. These results suggest that dopamine, octopamine and serotonin act directly on the muscle cells of the alimentary tract. Proctolin do not evoke any significant effect on the foregut.

Reorganization of peptidergic systems during brain regeneration in Eisenia fetida (Oligochaeta, Annelida)

After the extirpation of the brain reorganization of the peptidergic (FMRFamide, neuropeptide Y, proctolin) systems was studied in the newly forming cerebral ganglion of the annelid Eisenia fetida. During regeneration, all immunoreactive fibres appear on the 1st-2nd postoperative day. At the beginning of regeneration, immunoreactive neurons and fibres form a mixed structure in the wound tissue. On the 3rd postoperative day, FMRFamide positive and neuropeptide Y-immunoreactive, while on the 7th postoperative day proctolin-immunoreactive neurons appear in the loose wound tissue. From the 25th postoperative day a capsule gradually develops around it. The neurons of the preganglion move to the surface of the newly appearing preganglion. The number of these cells gradually increase, and by the 72th-80th postoperative days the localization and number of peptide-immunoreactive neurons is similar to that in the intact one. The neurons of all examined peptidergic systems may originate from the neuroblasts, situated on the inner and outer surface of the intact ganglia (e.g. suboesophageal and ventral cord ganglia). In addition FMRFamide and proctolin immunoreactive neurons may take their derive by mitotic proliferation from the pharyngeal neurons, too.

Distribution of Eisenia tetradecapeptide immunoreactive neurons in the nervous system of earthworms

A detailed mapping of Eisenia-tetradecapeptide-immunoreactive neurons in the central and peripheral nervous system combined with quantitative morphological measurements was performed in Eisenia fetida and Lumbricus terrestris. In Eisenia, most labelled neurons were observed in the ganglia of the ventral cord (20.38% of the total cell number of the ganglion) and 15.67% immunoreactive cells occurred in the brain, while 6% of the neurons could be shown in the subesophageal ganglion. In the case of Lumbricus, most immunoreactive cells were found in the subesophageal ganglion (16.17%) and in the ventral ganglia (12.54%). The brain contained 122 ETP-immunoreactive cells (5.6%). The size of the immunoreactive cells varied between 35-75 microm. A small number of Eisenia-tetradecapeptide immunoreactive fibres were seen to leave the ventral ganglia via segmental nerves, and labelled processes could also be observed in the stomatogastric system and the body wall. Labelled axon branches originating from the segmental nerves formed an immunoreactive plexus both between the circular and longitudinal muscle layer and on the inner surface of the longitudinal muscle layer. This inner plexus was especially rich in the setal sac. Among the superficial epithelial cells the body wall contained a significant number of immunoreactive cells. Only a few Eisenia-tetradecapeptide immunoreactive neurons and fibres occurred in the stomatogastric ganglia. In the enteric plexus the number of immunoreactive neurons and fibres decreased along the cranio-caudal axis of the alimentary tract. Eisenia-tetradecapeptide immunoreactive cells were also present among the epithelial cells in the alimentary canal. Some of these cells resembled sensory neurons in the foregut, while others showed typical secretory cell morphology in the midgut and hindgut.

Effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa in vitro

The effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa were investigated in vitro. The addition of taurine, within the range of 0-5 mmol l(-1), did not appreciably affect the motility of intact fowl spermatozoa. Motility remained almost negligible at 40 degrees C, while vigorous movement was observed at 25 degrees C. Even with the addition of Ca2+ before the addition of taurine, neither stimulation nor inhibition of motility was observed compared with the control (no addition of taurine). Similar results were obtained by the addition of taurine and calyculin A, a specific inhibitor of protein phosphatases. There were no changes in intracellular free Ca2+ concentrations, measured by a fluorescent Ca2+ indicator, fura-2, in taurine-treated spermatozoa. These results suggest that taurine is not involved in the regulation of fowl sperm motility and metabolism by intracellular Ca2+ mobilization in vitro.

Octopamine-containing neurons in the alimentary tract of the earthworm (Eisenia fetida)

Octopamine-containing nerve cells have been demonstrated in the enteric plexus of the earthworm (Eisenia fetida), applying immunocytochemistry and HPLC assay. A few octopamine-immunoreactive neurons occurred in the fore- and hindgut, whereas their number in the midgut was considerably greater. Octopamine levels detected by HPLC correlated with the distribution of octopamine-containing nerve cells. A regulatory role for these intrinsic octopaminergic neurons is suggested in the enteric plexus in the earthworm alimentary tract. This is the first report on the occurrence of octopamine-containing nerve cells in the peripheral nervous system of an invertebrate.

Unchanged intestinal absorption in rats fed a high sweet paprika-containing diet

The absorption rate of radiolabelled nutrients (22Na, 45Ca, [35S]methionine, [3H]leucine) was investigated in vivo in Sprague-Dawley rats at the end of a feeding period of 135 days on a semisynthetic diet containing 32% sweet paprika powder. No effect was seen on the intestinal absorption of these compounds, nor on the nutritive experimental parameters in these animals.

Hind limb somatosensory evoked potentials in the monkey: the effects of distal axonopathy

Computer-averaged short-latency somatosensory evoked potentials (SLSEP) to unilateral stimulation of the peroneal nerve were recorded from surface electrodes overlying the peripheral nerve, cauda equina, spinal cord, brainstem, and contralateral sensorimotor region. Seven monkeys were studied under normal conditions and at various stages of distal axonopathy induced by systematic acrylamide intoxication. With the use of a noncephalic reference, a series of five small-amplitude positive components were identified that precede the initial cortical activity. On the basis of timing and topography of the components, the source of the first one, SLSPEP1, was localized to the lumbar dorsal root fibers and that of the second, SLSEP2, to the ascending spinal tracts, principally gracile fasciculus. Bipolar recordings of the SLSEP2 overlying the rostral extreme of the cervical spinal cord provided a sensitive measure of the onset of distal axonopathy. Changes in the timing of this component antedated both abnormalities of spinal or peripheral nerve conduction and behavioral signs of intoxication. The initial alteration was specific to stimulation of the hind limb and was associated with early morphological change limited to the terminal and preterminal portions of the long axons in the gracile fasciculus.