摘要:

Most of the caries of African child populations is found in limited fractions of that population. The purpose of the present study was to analyze the caries situation of Sierra Leonean schoolchildren in relation to demographic, socioeconomic, and behavioral variables, in order to develop an appropriate index for prediction of caries. A total of 610 students from primary class 1 (mean age: 7 yr) and secondary form 1 (mean age 15 yr) were dentally examined by three examiners and interviewed by their teachers. Intra‐ and interexaminer reproducibilities were 82 and 70%, and interinterviewer reliability was 67–100% for the individual questions. Urban students had more caries than rural. In class 1, dmfs + DMFS was 4.1 and 1.8, respectively; in form 1, DMFS was 5.3 and 3.5. Two tribes (the Fulas and the Madingos) had higher caries means than the rest, especially in class 1, where dmfs + DMFS was 6.5 and 2.4, respectively. Form 1 students with literate parents had a higher caries mean, and class 1 pupils with defective school uniforms a lower mean. The apparently high‐risk groups did not consume more sweet snacks or clean their teeth less frequently. There was clearly more caries among the quartiles of children with most visible plaque on molars, but all social and demographic subgroups had similar amounts of plaque. Multivariate analyses of class 1 children showed that pupils living in urban areas, Fulas and Madingos, and children wearing complete school uniforms had caries significantly more frequently, other factors being equal. In form 1, urban students, rural Fulas and Madingos, students with literate parents, and urban students consuming sweet snacks frequently had significantly more caries. Social criteria were sufficient to identify rural children with high caries experience, but insufficient in urban

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01650.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Polydimethylsiloxan (silicone oil) adsorbs to solid surfaces and to teeth because of its low surface tension, forming a thin, resistant layer. Triclosan is a lipidsoluble, antibacterial substance which is added to toothpastes and mouthwashes to inhibit plaque. Triclosan can be dissolved in silicone oil, conferring an antibacterial property on the layer of silicone oil which forms on solid surfaces. The aim of the present study was to determine whether a toothpaste containing triclosan/silicone oil has any effect on established gingivitis in a test panel of 33 teenagers. This toothpaste and a placebo paste were randomly distributed to the panel, and the number of gingival bleeding points was recorded. No instruction in oral hygiene was given. The panel was then examined 4 wk later and the number of bleeding points again recorded. It was found that the reduction in bleeding points was significantly higher in the group which had used the triclosan/silicone oil paste than in the placebo group. Deposition of a lipid‐soluble, antibacterial agent in a layer of silicone oil which adsorbs to the tooth surfaces because of its physical properties represents a new and promising principle in preventive dentistr

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01651.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The aim of this study was to use the technique of in situ null ellipsometry to study some aspects of salivary film formation at solid/liquid interfaces. Experiments were performed in a fused quartz cell, and hydrophilic plasma cleaned silica and methylated hydrophobic silica surfaces were used as substrates. Samples of unstimulated whole saliva were allowed to adsorb on the test surfaces for 30 min. After the adsorption period, rinsing was performed for 5 min. Recordings were continued for another 30 min, and then new saliva samples were added in the cell. The results showed that statistically significant higher amounts were adsorbed on the hydrophobic than on the hydrophilic surfaces. The adsorbed films on both types of tested substrates consisted of loosely associated parts which were removed after rinsing and of more tightly adsorbed fractions. A significantly larger fraction was desorbed from the films adsorbed on the hydrophobic than on the hydrophilic surfaces. When saliva was introduced again in the cell, it was shown that the amounts adsorbed attained the values obtained before the rinsings. Increase in the concentration of saliva in the cell without previous rinsing did not cause any further increase in the mass of the adsorbed film.

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01652.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

We compared salivary epidermal growth factor (EGF) concentrations in patients with juvenile periodontitis (JP) and periodontally healthy controls. In initial screening of 45 JP patients and a group of healthy controls, significantly higher salivary EGF concentrations were measured in the JP patients. Subsequently, 17 JP patients who had high EGF concentrations in some of their salivary samples were chosen, and a group of age‐ and sex‐matched controls was selected. We then examined their EGF concentrations and EGF secretion rates under standardized conditions in stimulated and unstimulated saliva and studied the expression of EGF receptor (EGF‐R) in their gingival tissues. The results showed that the mean EGF concentration (pmol/ml) was slightly higher in JP patients than in controls. However, the difference was statistically significant only in stimulated saliva and when calculated per milligram salivary protein. When EGF release was measured as the rate of EGF secretion (pg/min), significantly higher values were observed in JP patients than in controls both in unstimulated and stimulated saliva. Immunofluorescence microscopy (IF) of gingival samples from JP patients and their controls revealed no quantitative or qualitative differences in the expression of EGF‐R. Our results demonstrate the complex nature of salivary EGF release. The elevated rate of salivary EGF secretion in JP patients may be associated with the pathogenetic mechanisms of juvenile period

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01653.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The aim was to study the ultrastructure of the surface of the temporomandibular joint (TMJ) in mature rats. The TMJs from control rats and rats given corticosteroids for 10 days or 38 days were examined. In three joints from the control rats the disk was detached from the condyle before preparation and analysis. Scanning electron microscopy was performed on the condyle, the disk, and the temporal component. Generally, the surface of the three components was predominantly smooth, although the condyle exhibited a more even surface than the disk and the temporal component. In the fossa a pitted or ridged appearance was observed in some areas. There was a striking difference between the surface structure of disks attached to, and that of disks detached from, the condyle during preparation. A prominent undulation of surface was evident in disks detacted from the condyle. Below the surface layer of the articular cartilage, a network of collagen fibers and fibrils running in all directions could be observed in all three components. In limited areas there was fibrillation and shallow defects of the surface layer. These changes were seen in all rats given corticosteroids for 38 days but also in some rats given corticosteroids for 10 days and in a few control rats.

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01654.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The amount of procollagen I carboxyterminal propeptide (PICP) in crevicular fluid (CF) was measured in three periodontitis patients. Samples were collected from 29 sites before treatment (scaling, root planing, and curettage) and 2, 5, 10, 20, and 40 days after treatment, by placing two paper strips in periodontal pockets for 5 s. The amount of fluid in strips was measured by the Periotron device. Control samples were collected from subjects with minimal gingival inflammation. PICP was extracted into saline solution and determined by a radioimmunologic method. Plaque index, papilla bleeding index, and pocket depth were recorded before and 40 days after treatment. The CF PICP mean concentration was 4.2 mg/1 in the pretreatment samples. Five days after treatment a statistically significant increase in PICP concentration was seen in all subjects. The peak appeared on days 5 or 10 in 27 sites. The mean peak PICP concentrations of the subjects were 5‐10 times higher than the pretreatment values. Twenty days after treatment, mean PICP concentration decreased to pretreatment level. PICP concentrations did not correlate with the clinical parameters. In control samples PICP amounts were below the detection limit. CF PICP is a new marker of type 1 collagen metabolism in periodontal tissues. It was concluded that elevated PICP concentrations in CF after periodontal treatment reflected increased type I collagen synthesis in periodontal tissues and that the peak in type I collagen synthesis takes place 5‐10 days after treatm

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01655.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A multiple linear regression analysis, with stepwise maximum R2improvement technique by forward selection and pair switching, was used to select the occlusal, morphologic, and histologic variables which explained most of the variation in bite force and electric masseter muscle activity. The variables comprised tooth contact and facial morphology together with thickness and fiber characteristics of the masseter muscle. The study included 13 healthy women, 21–28 yr of age, with a minimum of 24 teeth and no serious malocclusion. Significant exploratory models (R2: 0.55–0.85) were shown concerning bite force, and electromyographic amplitude during resting posture, maximal voluntary contraction (ICP), and unilateral chewing, as well as contraction time (chewing side). Muscle thickness and molar contact had a significant, positive effect on the level of forceful muscle contraction. The explorative model both demonstrated explicable relations, and offered better insight into interrelations than did univariate analy

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01656.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Mineral density of the trabecular bone of the mandible was determined by single‐energy QCT (quantitative computed tomography) for 74 totally or nearly edentulous menopausal women. These results were compared with the bone mineral densities (BMD) of their lumbar area (L2–L4) and femoral collum, measured by dual‐energy x‐ray transmission, Lunar DPX. The remaining height of the residual ridge at the symphysis of the mandible was measured on computed tomography (CT) lateral projection view, and an index of the residual ridge status was introduced. To determine whether general osteoporosis status affects the remaining height of the residual ridges, we compared these values with all results for bone mineral density. The BMD of the lumbar area and that of the femoral collum correlated well with each other, but the BMD of the trabecular bone of the mandible did not correlate with either of the other two BMD measurements. Measurements of residual ridge height did not correlate with any BMD values. The effect of possible bone loss earlier in life is no longer apparent in mandibular height or trabecular BMD over 20 yr after tooth extr

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01657.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Human bite forces have been studied with several types of equipment, and the maximal values reported have varied greatly. In the present study, a new bite force recorder was developed to measure human bite forces. When measuring maximal bite force, the mandible is, laterally and sagittally, almost in the intercuspal position, while the vertical opening of the jaws in the molar region is about 14 mm. Several teeth bite upon the housing. A quartz force transducer serves as a sensory unit. A microprocessor produces a numeric result, shown on a liquid crystal display (LCD). In order to adapt the sensor to be a part of a bite force recorder, we designed a unilateral housing of nonhardened tool steel. In laboratory calibration tests, a series of loads from 112.8 to 1691.5 N was used. The maximal bite forces of healthy undergraduate dental students, 15 men and 15 women, were investigated. The results for both genders remarkably exceeded the values previously reported for unilateral housings. The mean maximal bite force value in the molar region was 847 N for men and 597 N for women. The finding that pain or lack of muscular strength most often limited the clenching suggests that the actual masticatory potential was registered.

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01658.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The temperature rise, caused by 10 different curing units, in a prepolymerized resin specimen was examined. For all units, the temperature increase in a 60s cycle followed a logarithmic curve, with the most effective light sources giving the highest temperature rise. In the surface layer the change of temperature ranged between 3.6 and 29.2°C, and 3.2 mm below the irradiated surface between 1.5 and 12.3°C. The use of a 2‐mm‐thick isolating layer of glass ionomer resulted in a significant reduction in the temperature increase. The correlation between the depth of cure and the temperature rise was of an exponential or power nature; i.e., a small increase of the depth of cure was followed by a disproportionately high increase in temper

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1993.tb01659.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY