Prevention of enamel demineralization adjacent to glass ionomer filling materials

Abstract – In order to study the release of fluoride and prevention of enamel demineralization by different filling materials, standardized cavities were prepared in 80 extracted human molars. The cavities were filled as follows: 1. Fuji II F; 2. Ketac-Fil; 3. Ketac-Silver; 4. Silar. Twenty molars were used as controls (no filling). Enamel slabs with the fillings were subjected to 9 days of demineralization (30 min daily) and remineralization (artificial saliva, replaced daily). Fluoride release in the saliva was determined on days 1, 3, 5, and 9. Enamel fluoride content adjacent to the cavities was determined initially and after the de-remineralization using the acid etch technique. On day 1, the largest amount of fluoride in the saliva was released by Fuji, but on day 9 the largest amount was released by Ketac-Fil. Ketac-Silver released significantly less fluoride than Fuji and Ketac-Fil. The average initial fluoride content of enamel was 2200 ppm. After the test period, fluoride contents adjusted for biopsy depth were 1822, 1690, 1693, 1337, and 888 ppm in groups 1-5, respectively. The amounts of phosphorus dissolved by the second acid etch were 28.9 (SE 2.6), 30.2 (2.0), 34.4 (2.8), 44.1 (2.7), and 42.2 (2.4) μg, respectively. Softening of surface enamel during the test period was clearly reduced in teeth filled with Fuji and Ketac-Fil. The results show that glass ionomer materials release considerable amounts of fluoride and prevent demineralization of the adjacent enamel in vitro. Fuji and Ketac-Fil seem to be more effective than Ketac-Silver.     

A Controlled Study of the Influence of Continuous Subcutaneous Insulin Infusion Treatment on Diabetic Retinopathy during Pregnancy

ABSTRACT. Laatikainen L, Teramo K, Hieta-Heikurainen H, Koivisto V, Pelkonen R (Department of Ophthalmology, I and II Departments of Obstetrics and Gynaecology, III Department of Medicine, Helsinki University Hospital, Helsinki, Finland). A controlled study of the influence of continuous subcutaneous insulin infusion treatment on diabetic retinopathy during pregnancy. Forty consecutive pregnant patients with insulin-dependent (Type I) diabetes mellitus were randomized at the end of the first trimester for treatment with conventional insulin therapy (CIT) or continuous subcutaneous insulin infusion therapy (CSII). Nine patients randomized into the CSII group declined the pump treatment. The mean glycosylated haemoglobin (Hb A_1c) decreased (p<0.001) both in the CIT and the CSII groups with no difference between the groups. Some deterioration in retinopathy was found in 2/18 patients in the CIT group, in 5/13 in the CSII group, and in 3/9 of those who declined the pump treatment. The proportion of patients whose retinopathy progressed did not differ significantly between the groups, and in the majority the deterioration was mild. However, two patients in the CSII group developed acute ischaemic retinopathy, which progressed to proliferative stage in spite of laser treatment. In these two cases the decrease in the Hb A_lc level was among the greatest and fastest in the study. These data suggest that a rapid near normalization of glycaemic control by CSII during pregnancy can accelerate the progress of retinopathy in poorly controlled diabetic patients.     

Salivary S treptococcus mutans count and gingivitis in children after rinsing with a chlorhexidine-fluoride solution with and without strontium

Abstract Thirty schoolchildren, 9–12 yr old with high DMF score, rinsed their mouths twice a day for 3 days with a chlorhexidine-fluoride (CXF) solution or a chlorhexidine-fiuoride-strontium (CXFSr) solution. Streptococcus mutans counts (CFU) were made from saliva incubated on MSB agar and the gingival bleeding was recorded both before and after the rinsing period. S. mutans count decreased significantly immediately after the rinsing with each of the solutions (from 650 × 10³ to 170 × 10³ CFU/ml by CXF and from 500 to 170 × 10³ CFU/ml by CXFSr). Within about 18 days after the rinsing with each solution the salivary S. mutans counts returned to the original level. Gingival Bleeding Index (GBI) was significantly reduced by half through the CXF rinsing while the slight reduction by CXFSr was nonsignificant. Both of these changes were temporary. The results suggest that short rinsing periods with the CXF solution may be more advisable than daily rinses as a contribution to the maintenance of oral health in subjects or groups in need of such a prophylaxis. The weaker effect found with the CXFSr solution suggests that the cariostatic effect recently found in rats with the same solution may be due to other mechanisms than reduction of the oral S. mutans count.     

Isolation and ultrastructure of Bacteroides sp. with external cell-wall layer (S-layer) in periapical osteitis

Abstract – Bacteroides sp. was isolated in human periapical osteitis and shown to be biochemically closely related to B. ruminicola ssp. brevis and B. capillus. Electron microscopic examination revealed an external cell-wall layer (S-layer). The fractionation of cells by various methods gave partially purified sheets corresponding to the observed layer with a hexagonal molecular arrangement.     

Ultrastructural visualization of the adherence of Streptococcus mutans and Streptococcus salivarius to hydroxyapatite

Abstract – S. mutans and S. salivarius adherence to saliva-coated and saliva-uncoated hydroxyapatite was studied by transmission and high resolution scanning electron microscopy. No difference was observed between the saliva-coated and saliva-uncoated study series of adherence. The attachment of individual bacteria to apatite crystals was found to be mediated by cell wall projections. These electron-dense structures were characteristically well formed in S. mutans, and even in S. salivarius the projections appeared to link the bacteria to the apatite. The site of attachment in the bacterial cell wall was always at the division area. We suggest that the possible metabolic activity at the cell wall division site, therefore, also works in the adherence process.     

Occupational asthma due to stainless steel welding fumes

Seven patients with respiratory symptoms after welding were examined. Five had occupational asthma caused by fumes from manual metal are stainless steel welding. The detailed clinical results of two patients with repeated challenge tests are reported. One patient was nonatopic and had earlier had contact dermatitis due to chromium. He experienced a non-immediate type of asthmatic reaction after welding stainless steel. The other patient was atopic and showed an immediate-type reaction. Both reactions were repeated in the second provocation lest after about 2 years. In addition both disodium cromoglycate and beclomethasone pretreatments inhibited the reaction of the two patients, but a placebo medication did not. A remarkable amount of chromium and nickel are detected in the fumes released during stainless steel welding but not in the fumes from mild steel welding, with which all provocation tests were negative. The chromium or the nickel in welding fumes might be the aetiological factor of the reaction.     

Copper in human subgingival calculus

Abstract – The Cu concentration as well as the Ca, Mg, Fe, Pb, Zn, and F concentrations were determined in subgingival calculus and the relation of Cu to Zn, Ca, Mg and Fe described. Samples of human subgingival calculus of 60 pieces from 60 subjects were ashed in an acid solution and the cation concentrations were determined with atomic absorption spectrophotometry. The F content was analyzed with an ion-selective electrode. The data was analyzed using the multiple linear regression analysis. The mean ±SD of the Cu concentration in the subgingival calculus was 48.4 ±59.0 μg/g. Four elements, Zn, Ca, Fe and Mg, explained 41.1% of the Cu content. Zn explained 25.5% and the correlation was positive, whereas Ca (10.4%) had a negative correlation with the Cu content. The results showed such a high Cu content that it could affect the mineralization of calculus.     

Stress vulnerability and the effects of moderate daily stress on sleep polysomnography and subjective sleepiness

The purpose of this study was to investigate if and how sleep physiology is affected by naturally occurring high work stress and identify individual differences in the response of sleep to stress. Probable upcoming stress levels were estimated through weekly web questionnaire ratings. Based on the modified FIRST‐scale (Ford insomnia response to stress) participants were grouped into high (n = 9) or low (n = 19) sensitivity to stress related sleep disturbances (Drake et al., 2004). Sleep was recorded in 28 teachers with polysomnography, sleep diaries and actigraphs during one high stress and one low stress condition in the participants home. EEG showed a decrease in sleep efficiency during the high stress condition. Significant interactions between group and condition were seen for REM sleep, arousals and stage transitions. The sensitive group had an increase in arousals and stage transitions during the high stress condition and a decrease in REM, whereas the opposite was seen in the resilient group. Diary ratings during the high stress condition showed higher bedtime stress and lower ratings on the awakening index (insufficient sleep and difficulties awakening). Ratings also showed lower cognitive function and preoccupation with work thoughts in the evening. KSS ratings of sleepiness increased during stress for the sensitive group. Saliva samples of cortisol showed no effect of stress. It was concluded that moderate daily stress is associated with a moderate negative effect on sleep sleep efficiency and fragmentation. A slightly stronger effect was seen in the sensitive group.