摘要:

In recent years, several systems for computerized analysis of radiographs have been introduced, most of which use digital conversion of the image followed by subtraction of consecutive images to assess changes. This paper introduces a computer‐based qualitative and quantitative radiographic evaluation system based on the CADIA algorithm. Problems associated with computerized radiographic analysis are discussed and evaluation criteria for this type of system are suggested. These criteria include evaluation of system noise and threshold setting, reproducibility, and establishment of the system working curve (validity). The CARE system noise ranged from a ‐ 10 to + 10 CADIA value and the threshold was set on 13 for all measurements. The reproducibility was high, both for the radiographic technique and for repeated measurements. The working curve was established and showed the system's ability to detect small density changes of 0.048 O.D. which corresponds to 0.27 mm of aluminum thickness or compact bone equivalent. The linear range of the curve was between 0.7 and 1.8 O.D. By controlling the exposure parameters it was possible to work within the linear range of the curve. Based on these evaluation criteria, the CARE system can be used to quantitatively evaluate small density changes on sequential radiographs for early detection of caries and periodontal dise

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02089.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

We conducted a study to determine the sequence of cytokine and lipid mediator activation within the periodontium during the development of experimental gingivitis in humans. Crevicular fluid samples were collected from 7 previously cleaned, healthy patients at baseline, 1, 2, 3 and 4 weeks following the cessation of all oral hygiene measures. Gingival and plaque scores were taken at each visit to follow the development of gingivitis and plaque retention. Crevicular fluid samples were assayed in quadruplicate for prostaglandin E2(PGE2), thromboxane B2(TxB2), leukotriene B4, interleukin‐1β (IL‐1β) and tumour necrosis factor alpha (TNFα) by RIAs or ELISAs, maintaining site pairing to examine temporal changes. Redness scores (expressed as mean percentage of sites with redness present) increased almost linearly from a baseline value of zero to approximately 40% at 1 week, 59% at 2 weeks, 83% at 3 weeks and 100% at 4 weeks. The mean % of sites with bleeding on probing increased gradually from zero at baseline to 5% at 3 weeks and then rose abruptly to 25% at 4 weeks. CF‐PGE2and CF‐TxB2levels remained fairly stable at baseline levels for the first 3 weeks then rose sharply by 2.5‐ and 2‐fold, respectively, at 4 weeks. CF‐LTB4levels increased 2‐fold by 1 week and 4‐fold by 4 weeks. The CF levels of IL‐1β increased abruptly from mean baseline values of 16.5±9.3 ng/ml to 131±76.0 ng/ml at 1 week and remained at this level for the duration of the experiment. CF‐TNFα levels were non‐detectable throughout the experiment (i.e.<2 ng/ml). These data suggest that LTB4and IL‐1β are involved in the earliest stages of gingivitis and that increases in the cyclooxygenase products PGE2and TxB2occur later and are associated wi

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02090.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

We previosly reported that hot aqueous phenol extraction ofPorphyromonas gingivalisyields a preparation containing both lipopolysaccharide (LPS) and an antigenically distinct capsular polysaccharide (PS). In the present study, we examined the capacity of phenol‐water extracts from a number of strains ofP. gingivalisto activate human serum complement. Anticomplementary activity of extracts from two invasive and two noninvasive strains ofP. gingivaliswas assessed in a sheep erythrocyte hemolytic assay and in an alternative pathway‐selective rabbit erythrocyte hemolytic assay. In the sheep erythrocyte assay, extracts from noninvasive strains were found to exhibit greater anticomplementary activity than extracts derived from invasive strains. A phenol‐water extract from invasive strain ATCC 53977 was further resolved into its LPS and PS fractions. Whereas isolated LPS from this strain exhibited strong anticomplementary activity, the PS fraction was only weakly active. Phenol‐water extracts from three of four strains were found to be potent activators of the alternative pathway, with extracts from the two noninvasive strains being most active. The extract from the remaining strain (ATCC 53977) was a poor activator of the alternative pathway. Further analysis of this extract revealed, however, that the LPS fraction was a potent activator of the alternative pathway, although the PS fraction exhibited negligible activity. The results of this study indicate that phenol‐water extracts of invasive and noninvasive strains ofP. gingivalisdiffer in their respective anticomplementary activities, with invasive strains being less active. Although extracts from both invasive and noninvasive strains activated the alternative pathway, this activity appears to be attributable to the LPS, rather than the PS,

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02091.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Using analytical electron microscopy, we directly tested the hypothesis that transition metals and sulfur are the cause of chlorhexidine‐induced tooth stain. Plaque scraped from the teeth of water‐treated individuals or chlorhexidinetreated “non‐stainers” was non‐or lightly‐stained and contained low concentrations of sulfur and transition metals. Tooth scrapings from heavily‐staining chlorhexidine‐treated individuals consisted of distinct unstained and stained regions. The stained regions were organic but were in close proximity to mineralized areas. Enhanced levels of sulfur and transition metals, particularly iron, were found in stained regions, whereas unstained regions contained low sulfur and metal levels similar to the water‐treated or non‐staining individuals. Excluding decreased mineralization, the major elemental change in heavily‐stained plaque was an increase in sulfur, and to a lesser extent, iron and other transition metal. Sulphur and iron levels were directly correlated. Following chlorhexidine treatment with iron supplementation, staining was enhanced, the Fe/S ratio increased, and sulfur and iron remained correlated. These data support the hypothesis that transition metals and sulfur are the cause of chlorhexidine‐induced tooth stain. The data are consistent with chlorhexidine treatment altering the incorporation into plaque of a natural sulfur‐containing organic component of saliva or bacteria. This natural component appears to readily interact with transition metals, particularly iron,

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02092.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The search for markers of periodontal disease activity and progression has accelerated over the last decade, in an effort to replace existing subjective clinical measures of periodontal health status. Research is being aimed at establishing more objective and quantitative methodology, capable of rapid diagnosis prior to the appearance of clinical signs of destructive disease. Such tests need to be sensitive enough to evaluate individual periodontal sites in health as well as disease states. We report the development of a new chemiluminescent assay for the enzyme alkaline phosphatase, that is capable of quantifying the enzyme in sub‐microliter volumes of gingival crevicular fluid and serum. The technique will measure alkaline phosphatase (ALP) whilst immobilised on paper strips, without the need for an elution stage. It is simple, versatile and amenable to chair‐side use. We discuss in detail the assay procedure and have examined levels of ALP in 11 adult volunteers with clinically healthy periodontal tissues. The mean ALP concentration was 2135 IU/L for GCF and 183 IU/L for serum, a 12‐fold difference. There also appeared to be an “oral pattern” of enzyme distribution in healthy periodontal sites, with levels being higher in the anterior region of the mouth and highest in the lower anteri

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02093.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

In the present study an assay for the attachment ofT. denticolato epithelial cells is described. An indirect immunohistochemical staining method, using two native polyclonal antisera, revealed dark‐brown coloured spirochetes attached to rat palatal epithelial cell (RPE) monolayers. In addition, two morphologically distinct populations of RPE cells could be distinguished in the monolayers when using phase contrast microscopy. One minor population consisted of isolated rounded RPE cells that were lying on top of a confluent monolayer of flattened RPE cells. The rounded RPE cells were more receptive for the attachment ofT. denticolathan the flattened cells. The rounded RPE cells were evenly distributed over the monolayer, but the attachment of spirochetes to the rounded cells was greater at the edge than in the centre of the monolayers. The percentage of rounded RPE cells with attached spirochetes depended on the incubation time (optimum 6 h), temperature (optimum 37 C) and pH (optimum 7.0). It is speculated that the attachment ofT. denticolais a physical/chemical process of yet unknown nature and that differences in the number of microvilli and/or the amount of available receptors, between the two morphologically distinct cell types, accounts for the differences in the numbers of attached spirochete

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02094.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The present study details the structural and ultrastructural features of healing events between the regenerated periodontal ligament and the root surface after experimental periodontal disease. Experiments were performed on dogs, and the concept of guided tissue regeneration was tested using resorbable polyurethane membranes. Light microscopy, scanning‐ and transmission electron microscopy were employed to determine if healing events involve regeneration (ie, process by which the architecture and the function are completely renewed) or periodontal repair (ie, healing of a wound by tissue that does not fully restore the architecture of a part). Regeneration occurred in parts of the roots only if some original cementum remained on the root surface after root planing. Repair was observed if peripheral dentin was removed by root planing as this layer was not reestablished. In areas remote from the base of the defect, new collagen fibrils, synthesized by fibroblasts and oriented perpendicular to the root surface, were spliced with severed ends of Sharpey's fiber bundles of original cementum. If circumpulpal dentin was exposed, intermingling between new fibrils with dentinal matrix fibrils occurred. In areas near the base of the defect, the first event was the formation of a cementoid by a cementoblast monolayer and subsequent formation of intrinsic fibrils oriented parallel to the root surface. Afterwards, the cementoblast monolayer disintegrated and extrinsic fiber bundles became anchored in the new cellular mixed fiber cementum. In these areas, linkage between new cementum and pre‐existing tissues always occurred by interfacial intermingling of the fibrils, regardless of whether new attachment occurred at circumpulpal dentin or original cemen

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02095.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The non‐human primateMacaca nemestrinawas evaluated for use as a potential model in periodontal research by study of 16 animals. Using one incisor, premolar, and molar per quadrant, we measured supragingival plaque, severity of gingival inflammation, and pocket depth, and analyzed the subgingival flora. Serum IgG titers and avidities to antigens ofPorphyromonas gingivalis(Pg) andActinobacillus actinomycetemcomitans(Aa) were also assessed. Ten animals were between 13 and 24 years old, and six were between 4 and 5 years old. While mean gingival inflammation scores were significantly higher for older than for for younger animals (2.2 vs 1.8, p<0.05), mean plaque index scores and mean probing depths did not differ significantly. The animals harbored a subgingival microflora considered to be pathogenic for humans including Aa, Pg,Bacteroides forsythus, Prevotella intermediaI and II,Campylobacter rectaandFusobacterium nucleatum. Aa, however, was found only in the younger animals. All of the animals had serum IgG antibodies reactive with antigens of Pg and Aa, and titers for Pg but not for Aa were significantly higher in the older relative to the younger animals (t test p<0.02). In contrast, antibody avidity did not significantly differ between the two groups. A combined clinical assessment index based on maximum probing depth, gingival index score, and tooth loss was used to assess the overall disease severity. Titers were positively associated with disease severity (Spearman's rank correlation 0.57, p=0.02). We conclude thatM. nemestrinaharbors a subgingival microflora considered to be pathogenic for humans, manifest serum IgG antibodies to antigens of Pg and Aa, and exhibits clinical features of periodontitis comparable to those seen in humans. This species appears, therefore, to be a useful model for investigating periodontal microbial‐host interactions, including the immune respo

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02096.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The experimental gingivitis model has long been used to evaluate chemotherapeutic agents in mouthrinses. Only recently however has the model been modified to test undiluted dentifrices by using a toothshield both to apply dentifrice and to protect selected teeth from toothbrushing. This also enables participants to brush the rest of the mouth and avoid the unpleasantness of 3 weeks without oral hygiene. Because of its well‐documented efficacy, chlorhexidine was used in a toothpaste formulation to investigate the validity of the partial‐mouth, experimental gingivitis model for evaluating therapeutic dentifrices. Optimal gingival health was established in 88 adults, who then were randomly assigned to two equal groups. A toothshield was constructed for each subject to fit the teeth of one mandibular quadrant. During the trial chlorhexidine or placebo dentifrice was applied undiluted to the test teeth via the toothshield, which also prevented plaque removal during brushing of the remaining dentition. After 21 days, plaque and gingivitis had developed in both groups. However, the chlorhexidine group had significantly less plaque and gingivitis than the placebo group. No adverse soft tissue effects were observed. This study demonstrated that the partial‐mouth, experimental gingivitis model allowed unhindered development of plaque and gingivitis that was comparable to whole‐mouth studies in which oral hygiene was suspended for 3 weeks. By corroborating with chlorhexidine, it is concluded that this short‐term clinical model is valid for evaluating the chemotherapeutic effects of de

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02097.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1993.tb02098.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY