摘要:

Abstract –A multiple choice test with nine statistical questions was sent to a random sample of Danish dentists to assess their knowledge of elementary statistical expressions (SD, SE, P0.05 and r). Of 250 dentists, 129 (52%) answered the questions. The test was also completed by 27 (71%) of 38 dental students immediately after the last lecture in statistics. The median number of correct answers was 2.2 among the dentists and 3.4 among the dental students. It is concluded that the statistical knowledge of most dentists, and to a lesser degree also dental students, is so limited that they cannot be expected to be critically against or to draw the right conclusions from those statistical analyses with which they are confronted. Only 35% of the dentists stated that it is very important that this problem be raise

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01557.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –The aim of this study was to examine the distribution of organic material in mature enamel surfaces immediately prior to eruption. Thirty‐six samples of buccal or lingual enamel from unerupted third molars were prepared for transmission electron microscopy by a method involving demineralization of the enamel after embedding in Epon. The results showed that at time of eruption human surface enamel is a highly porous structure containing large amounts of developmental protein which appear as a variety of triangular, funnel‐shaped, or invaginated configurations extending into the enamel. The implications of this finding may be of importance to the understanding of early caries lesion formation in the enamel since organic structures may modify the diffusion of ions in and out of the t

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01558.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –Giant tubules in the axiomesiodistally extended incisal dentin of unerupted permanent bovine incisors from 1/2‐11/2‐yr‐old calves were studied by TEM. The pulpal portion of each giant tubule contained two capillaries forming a loop incisally. The capillaries consisted of a delicate, continuous, or fenestrated endothelium and often had a pericyte coating. Cells with a rich RER, mitochondria, and Golgi apparatus dominated along and just incisal to the vessels. Extravasated erythrocytes and occasional macrophages were also seen in the latter location. It was suggested that the pulpal retraction of the giant tubule vessels during primary dentinogenesis might be the result of an intermittent sequestration of the most incisal portion of the loop, concomitant with endothelial proliferation in the pulpal portion of the capillaries. The major portion of the giant tubules, incisal to the vessels, contained a dense matrix of more or less axially oriented unmineralized 0.07–0.1‐um‐thick collagen fibrils and single cells showing gradually increasing degenerative and necrotic changes in an incisal direction. Longitudinal sections of the mineralized tubular walls revealed transversely cut collagen fibrils. The incisally located giant tubule origins were circumvented by dentinal tubules and contained 0.10–0.22‐um‐thick, densely packed collagen fibrils with an electron dense

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01559.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non‐carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30‐min immersion in 0.1 M lactic acid‐NaOH buffer. During the 9‐day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9‐ day period, and after the 1‐h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1‐h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride co

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01560.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –An in vitro system for isolated dentinoclasts is described in which clastic cells which are not contemporaneously engaged in resorption are gently rinsed from the surface of actively resorbing root dentin. Dentinoclasts were cultured on a variety of hard tissue constituents in order to investigate the effects of substratum composition on the expression of resorbing structures by these cells, and examined with scanning electron microscopy. Results revealed that dentinoclasts express both ruffled borders and clear zones only when cultured on coverslips coated with both collagen and hydroxyapatite. Hydroxyapatite alone induced only the formation of a clear zone. Failure to express either clear zones or ruffled borders by cells cultured on collagen‐coated coverslips was interpreted to reveal that collagen itself is not capable of, but requires the mineral component of hard tissue for, producing morphologic resorbing structures in clastic ce

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01561.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –Unerupted permanent bovine incisors studied by routine autoradiography using radioactive proline incorporation revealed collagen formation within the giant tubules situated in the incisal dentin. A high [3H]‐proline labeling was seen within the pulpal vascularized portion of the giant tubules, as well as in association with groups of cells immediately incisal to the blood vessel loops. The incisal portion of the giant tubules showed no or insignificant [3H] ‐proline lab

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01562.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –The objective was to compare the erosive effect of some commonly used acidic drinks and milk products on a bovine tooth enamel model system. Conditions were selected to be sufficiently severe to cause erosion. Loss of material after erosion experiments was measured by recording the depth of the surface profile after repeated and prolonged exposure. Changes in the enamel surface were observed by scanning electron microscopy. The reparative mechanisms were studied by immersing test teeth in saliva, with or without (2 ppm) fluoride, after severe demineralization in the test products. According to the t‐test for paired means, cola beverages and orange beverages differed from beer, coffee with or without sugar, strawberry yoghurt, buttermilk, and carbonated mineral water at the levelP0.01. Each of the last‐mentioned test products differed from sports drinks, diet cola beverages and orange juice less significantly. In addition, bathing of teeth in saliva between exposures to the test products did not influence the erosive depth. The results, based on in vitro conditions that ensured erosion, are useful for comparative purposes but cannot be directly extended to the oral cavity under normal use condi

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01563.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –Electrometric sensitivity of permanent maxillary central incisors was studied longitudinally in 34 children at 6‐month intervals over 2½ yr (mean age of the children at the beginning of the study: 94.6 months). Root development stages were determined from radiographs obtained at the beginning of the study, after 1 yr, and after 2½ yr. An increase in sensitivity was found over the study period, but large variations were found from child to child and even within the same child. Especially at the first examinations a few children showed very low sensitivity. Statistical analysis showed that examination number, root development and side of the mouth (right or left central incisor) all were statistically significantly related to sensitivity. Statistically significant differences were also found between the indivi

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01564.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –The immunohistochemical occurrence of several different neuronal markers has been investigated in human gingiva with phenytoin‐induced overgrowth. The material was compared to gingival material taken following surgical orthodontic treatment. Gingiva obtained from the phenytoin‐treated groups seemed to have a reduced number of neurofilament (NF) immunoreactive nerve fibers in the propria compared to control material. In both phenytoin as well as control gingiva sparsely distributed, thin, calcitonin gene‐related peptide (CGRP) and substance P (SP) immunoreactive fibers were found in the propria. No obvious differences between the two groups could be observed for CGRP and SP. Immunoreactive cells for somatostatin (SOM) with a dendritic cell shape were found in the propria in both groups, sometimes in densely packed clusters. A tendency for increase of SOM‐immunoreactive cells in the phenytoin‐treated gingiva was observed. A few γ‐melanocyte stimulating hormone (γ‐MSH)‐immunoreactive cells with a round appearance were found in control as well as phenytoin‐affected gingiva. In one instance, however, a heavy γ‐MSH‐immunoreactive cell infiltration was seen in the phenytoin sample. No immunoreactivity in either the phenytoin‐treated group or in the control group was seen for proctolin or galanin. The results indicated that gingiva with phenytoin‐induced overgrowth has a reduced innervation density reveale

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01565.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract –Antitumor immunity was assessed in a group of 10 patients suffering from squamous cell carcinoma of the oral cavity using the humoral leukocyte adherence inhibition assay (H‐LAI). A tumor extract from a person with cancer of the tongue was used as antigen. Sera from five patients with carcinoma of the tongue were all positive in the test. Of the other five patients, three had cancer of the lips while in two patients the type was unspecified. All patients except one with cancer of the lips gave a positive response in the test. Thus, of the 10 patients with carcinoma of the oral cavity, nine responded. Among nine controls, one person gave a positive respo

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1988.tb01566.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY