摘要:

The 5-year incidence and intraoral distribution of decayed and filled root surfaces were evaluated in 379 black and 323 white residents of North Carolina aged 65 and older. During the period of study, approximately 39% of blacks developed at least one root DFS compared with 52% for whites (Wald χ2 test, p = 0.062). When the results were calculated using the net root DFS increment, blacks did not have significantly higher rates than whites over the 5-year study period (0.52 surfaces/person versus 0.42 surfaces/person, Survey Regression, n = 363, p = 0.708). However, for blacks, the 5-year incidence density rate of root DFS was 0.26 per 60 surface-months at risk, and for whites the rate was 0.19 new root DFS per 60 surface-months (incidence density ratio = 1.33, 95% CI = 1.01–1.76, p = 0.047). Intraoral distribution patterns for root caries incidence revealed that the approximal surfaces of the anterior teeth were involved most frequently, particularly in the mandible and maxilla in whites, followed in decreasing order by the buccal surfaces of the lower anteriors and the mesial surfaces of the upper anteriors in blacks. Although root caries incidence rates were obviously low, there were significant differences in the occurrence of caries between blacks and whites. The pattern of occurrence was similar for both races with root surface disease being concentrated in the approximal surfaces of the anterior teeth in a small proportion of affected individuals, with whites presenting more filled root increments than blacks. These findings suggest a need for more caries treatment in blacks and increased monitoring of this population since they are at a higher risk for root cari

ISSN:0008-6568    

DOI:10.1159/000262156

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Samples of whole saliva and dental plaque were collected from initially 10-year old subjects who participated in a 40-month cohort study investigating the effect of chewing gum usage on caries rates. The subjects represented nine cohorts of which one did not receive gum, while in eight cohorts the subjects received gum containing either xylitol, sorbitol, their mixtures, or sucrose as bulk sweeteners, the maximum sweetener consumption in the form of gums being up to 10.7 g/day, used in 3–5 daily chewing episodes. Gum usage had no significant effect on the levels of salivary protein, IgA, α-amylase, peroxidase, lysozyme, SCN- and buffer capacity. At the endpoint, the group that received 100% xylitol pellet-shaped gum five times/day, had significantly lower levels of sucrase (p < 0.05) and free sialic acid (p < 0.001) in whole saliva than at baseline. This group showed significantly (p < 0.05) smaller plaque index scores at two cross-sectional measurements, and exhibited the lowest log10 counts of salivary lactobacilli at endpoint than most other groups. The salivary levels of peptidase(s) (oligopeptidase B-like enzymes) hydrolyzing Nα-benzoyl-DL-arginyl-p-nitroaniline were significantly (p < 0.05) or almost significantly lower in groups which received 100% xylitol pellet gums. All groups exhibited obviously an aging-related increase of salivary mutans streptococcus scores, except the above xylitol group in which the mean scores did not cha

ISSN:0008-6568    

DOI:10.1159/000262157

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Grey discolouration around occlusal amalgam restorations has been found to be useful for the diagnosis of secondary caries. The aim of the present in vitro study was to establish the validity of grey discolouration of buccal and lingual enamel next to the approximal amalgam of class II restorations for the diagnosis of secondary caries. One hundred buccal and lingual areas next to the approximal parts of a class II filling in molars and premolars were included in the study. Fifty-one areas showed grey discolouration. Validation was performed against radiographs of transverse sections. Both radiolucencies and radiopacities were scored as being caries. The results were: sensitivity 92%, specificity 55%, positive predictive value 22% and negative predictive value 98%. It was concluded that grey discolouration of the approximal walls next to class II amalgam fillings is not useful for the detection of secondary caries, but the absence of grey discolouration gives a good prediction for the absence of secondary caries. This is in contrast to grey discolouration around occlusal amalgam restorations, which was considered to be useful for the diagnosis of secondary caries.

ISSN:0008-6568    

DOI:10.1159/000262158

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The aim of the present investigation was to study two post-brushing water rinsing procedures: (1) on fluoride (F) accumulation in approximal dental plaque, and (2) on F clearance in the interdental area. Twenty subjects participated first in the accumulation study, including three experimental periods (A, B and C), each lasting for 7 days. During period A, they brushed with a 0.32% NaF dentifrice for 2 min, followed by a 1-min active mouth rinse with the toothpaste foam combined with 5 ml of water. During period B, the 2-min brushing was followed by three quick water rinses with 15 ml each. During period C, toothbrushing, which was carried out without any toothpaste, was followed by a 2-min active mouth-rinse with 10 ml of a 0.05% NaF solution. All three procedures were performed in the morning (after breakfast) and in the evening (just before bedtime). The results showed that the accumulation of F in pooled approximal plaque after 7 days reached on average 2.7 times higher values after procedure A than B (p < 0.001). Procedure C also resulted in more F in plaque than B (p < 0.001). The same 20 subjects participated in the clearance study on a separate occasion. When measuring the F concentration in the interdental area at 3 h after the application, procedure A resulted in a significantly higher F concentration than both toothbrushing B and mouth rinse C; the AUC was 2.2 times larger for A than for B (p < 0.001). Thus, both the accumulation of F in approximal plaque and the clearance of F in the interdental area are related to the mode of water rinsing after toothbrushing.

ISSN:0008-6568    

DOI:10.1159/000262159

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Forty children aged 8–10 years participated in this study. Half (n = 20) of them used orthodontic appliances which contained fluoride-releasing devices embedded in the lingual surface of the appliance and the other half used orthodontic appliances prepared from a fluoride-releasing acrylic polymer. Prior to the adjustment of appliances and after 1, 7, 14, 21 and 30 days salivary and urinary samples were collected and the fluoride concentrations were determined. The mean fluoride release was highest during the first week. However, the values decreased considerably after that and the curves for the two groups became parallel. The results indicate that fluoride-releasing removable appliances could be useful for a prolonged release of low concentrations of fluoride without any systemic effec

ISSN:0008-6568    

DOI:10.1159/000262160

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The fluoride content of the enamel and dentine of premolars was used as a determinant of the availability of ingested fluoride in New Zealand prior to and following the introduction of water fluoridation 40 years ago. Premolar teeth, which developed during the periods (PRE and POST respectively) under study, were selected from teeth extracted from 12 to 14-year-old children resident in different geographic areas in the country. The fluoride content, determined by multiple proton microprobe analyses, of surface enamel, deep enamel, and dentine, were for PRE teeth 440, 65 and 115, respectively. For POST teeth the mean values were significantly (p < 0.001) higher, by 69, 29 and 102% respectively. The relevance of the change in fluoride content was assessed by comparison with published reports on the fluoride content of teeth developed in communities exposed to low ( 3 ppm) naturally occurring fluoride levels in drinking water. The PRE teeth had a fluoride content associated with a low fluoride exposure and POST teeth with optimal fluoride exposure during tooth development. It was concluded that fluoride availability in New Zealand teeth had increased over the past 30 years but this increase is compatible with exposure of the community to optimal rather than excessive levels of ingested fluorid

ISSN:0008-6568    

DOI:10.1159/000262161

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Citric acid contained in beverages and foods is one of the main causes of enamel erosion. It was hypothesized that the clearance of citric acid from saliva would influence the degree of salivary saturation with respect to hydroxyapatite (OHAp). Ten subjects rinsed with 2% citric acid, pH 2.1, for 5 s. Before and at 1, 2, 5, 10 and 15 min after the rinse, a small saliva sample was collected. The sample pH, ionic strength and the concentrations of ionized calcium, inorganic phosphate and citric acid were determined. The pH of the saliva decreased from 7.21 ± 0.40 (mean ± SD) at time zero to a minimum of 6.46 ± 0.88 at 1 min after the rinse. It was back to baseline value after 15 min. The saliva was supersaturated with respect to OHAp at time zero. After the rinse with the citric acid the saturation level shifted to undersaturation in all individuals except one. At 1 and 2 min after the rinse the saliva was, on average, undersaturated. After 5 min the average saturation level was back to supersaturation. The individual differences were large. The correlations between the rate of clearance of citric acid during the 1 minute and the mimimum degree of saturation with respect to OHAp at 1, 2 and 5 min after the rinse were significant (r = 0.84, r = 0.76 and r = 0.79, respectively). In conclusion, rinsing with citric acid will cause a decrease in the saturation level with respect to OHAp in a highly individual patte

ISSN:0008-6568    

DOI:10.1159/000262162

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Dentine consists simplified of mineral and of several organic components. Sodium hypochlorite (NaOCl) is a well-known nonspecific proteolytic agent capable to remove organic material. The aim of this study was to investigate the influence of organic material removal from artificial dentine lesions by means of NaOCl pretreatment on subsequent remineralization with and without fluoride. Human root dentine samples were demineralized in an acidic gel (pH = 5) at 37°C for 2 weeks. After 2 min of pretreatment with a 0.4, 2 or 10% NaOCl solution, the samples were remineralized in a 20 mM HEPES buffer (pH = 7) containing 1.5 mMCa2+ and 0.9 mM phosphate with or without addition of 10 ppm F– as NaF at 37°C for 8 days. Mineral profiles were assessed by means of transversal micro-radiography after diol treatment to avoid shrinkage caused by drying. In a separate experiments the dentine contraction caused by 10% NaOCl was assessed. The contraction (negligible for sound dentine) was found to be about 12% for the lesions. The remineralization results showed that pretreatment with a 10% NaOCl solution for 2 min, increased lesion remineralization. After NaOCl treatment, the amount of accumulated mineral increased by about 27% without F in the remineralization solution, and by about 4% with 10 ppm in solution. The in vitro results suggest that removal of organic materials from dentine lesions is an interesting approach to enhance remineralizat

ISSN:0008-6568    

DOI:10.1159/000262163

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The change in proliferative and metabolic activities of human dental pulp cells responding to carious stimuli was studied by means of immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and silver-binding nucleolar organizer region (AgNOR) staining. We classified the pulp tissues into five groups according to the progression of dental caries, ranging from grade 0 (the pulp of noncarious teeth) to grade 4 (the pulp of perforated carious teeth). PCNA-positive pulp cells were detected only in advanced dental caries (grades 3 and 4), and the difference in immuno-positive rate was significant between the two grades (p < 0.001). However, the mean number of AgNORs per nucleus increased even in the early phase of dental caries, significant differences being detected between grades 1 and 2 (p < 0.005), 2 and 3 (p < 0.005), and 3 and 4 (p < 0.001). Our data suggested that the metabolic activity of dental pulp cells was enhanced in the early phase of dental caries. However, proliferation of pulp cells occurred later in small degrees during fully developed caries such as grades 3 and 4. The slow and weak response in cellular proliferation might contribute to the usual fragility of the pulp to various assaults including caries or pulpitis.

ISSN:0008-6568    

DOI:10.1159/000262164

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Caries mainly occurs at retention sites for plaque such as pits, fissures, margins of restorations and interproximal sites. An in vitro model was developed to investigate dentine caries in narrow gaps. Forty bovine coronal dentine discs were covered with bonding agent. In 20 discs, two grooves, 200 and 340 μm wide and 500 μm deep, were sawn to mimic fissures. In the 20 other discs, a 1-mm-wide groove was made and, after polyester sheets were placed against both walls, filled with composite. After curing of the composite and removal of the sheets, grooves of 22 μm remained at the borders of the restoration. All grooves were exposed to 8% methylcellulose gel 0.1 M lactic acid at pH 4.8 for 1 week. Demineralization was determined by microradiography of sections sawn out of the center of the discs. The walls of the grooves showed subsurface lesions, which decreased in size towards the base of the grooves. The average mineral losses (vol%×μm) at the entrance of the 22-, 200- and 340-μm-wide grooves were 1,112 (SD 370), 1,277 (293) and 1,277 (255), halfway down the groove 218 (150), 659 (244) and 797 (207) and at the base of the groove 140 (88), 285 (145) and 504 (205), respectively. Analysis of variance and Tukey’s B test showed that the average mineral losses from grooves of different width and from sites at different depth were all significantly different at p < 0.05 level, but not for the mineral losses from the entrance of the two wider grooves and from the two lower sites in the narrowest groove. The reduced mineral loss in the two narrower groove widths is assumed to be caused by the more limited inward diffusion of acids and outward diffusion of mineral ions through the methylcellul

ISSN:0008-6568    

DOI:10.1159/000262165

出版商:S. Karger AG    

年代:1996

数据来源: Karger