bluuebunny/crossref_metadata_2025 huggingface dataset:
Salivary Carbonic Anhydrase Isoenzyme VI Is Located in the Human Enamel Pellicle
Authors: Leinonen Jukka , Kivelä Jyrki , Parkkila Seppo , Parkkila Anna-Kaisa , Rajaniemi Hannu
Published: April 2003

Salivary carbonic anhydrase (CA VI) appears to protect teeth from caries via mechanisms other than direct regulation of salivary pH and buffering capacity. To elucidate whether CA VI acts in the local microenvironment of the tooth surface, we studied the location and activity of the enzyme in the human enamel pellicle. The study was performed using a specific rabbit antiserum to human CA VI in conjunction with immunostaining and immunoblot techniques. CA activity was demonstrated using a histochemical staining method. CA VI immunostaining of extracted teeth having in vivo formed pellicle showed that the enzyme is present in the enamel pellicle. Immunostaining for salivary α–amylase, which is known to be present in the pellicle, showed a similar staining pattern. The presence of CA VI in the enamel pellicle was confirmed by immunoblotting of in vivo formed pellicle proteins. In vitro studies showed that CA VI binds to polished enamel surfaces from both saliva and solutions of purified enzyme. The intensity of the CA VI immunostaining on the enamel surface was dependent on the concentration of the applied enzyme. The histochemical staining of in vitro formed enamel pellicle confirmed that the bound enzyme retains its enzymatic activity. The presence of active CA VI in the human enamel pellicle suggests that it may accelerate the removal of acid by functioning locally in the pellicle layer on dental surfaces.
Associations between Microbiological and Salivary Caries Activity Tests and Caries Experience in Hungarian Adolescents
Authors: Gábris K. , Nagy G. , Madléna M. , Dénes Zs. , Márton S. , Keszthelyi G. , Bánóczy J.
Published: April 2003

The aim of the study was to assess caries prevalence in connection with salivary caries–related findings in 349 14– to 16–year–old Hungarian adolescents living in two different cities. DMFT, DMFS means, stimulated salivary flow, buffer capacity, mutans streptococci, lactobacilli and candida counts in saliva were determined. The ratio of caries–free adolescents was 4.6% in the total population sample, DMFT mean values were 7.24±4.86, DMFS means 10.50±8.35. Mean secretion rate of stimulated saliva was 0.84±0.50; a low buffer capacity was found in 6.3% of the examined children. The ratio of carriers of mutans streptococci, lactobacilli and yeasts in saliva was 89.7, 73.9 and 47.7%, respectively. DMFT and DMFS values as well as mutans streptococci and candida counts were lower in the capital than in the other city. Statistically significant correlations were found between DMFT, DMFS mean values, and salivary microbiological counts.
Fluoride in Enamel Lining Pits and Fissures of the Occlusal Groove–Fossa System in Human Molar Teeth
Authors: Pearce E.I.F. , Larsen M.J. , Coote G.E.
Published: April 2003

The fluoride (F) distribution in enamel lining the occlusal fissures of human molars and premolars is difficult to investigate by normal microsampling techniques, yet this information is of importance as fissures are particularly susceptible to caries. We have used the proton probe to map the distribution of F and Ca in sections of 17 molar teeth collected from Danish and New Zealand populations. The caries status of the sectioned fissure was determined by microradiography or visually after drying. The probe scans were graphed as density images, surface plots and topographical plots. Sound enamel bordering grooves and fissures showed a high–F surface layer, in 1 sample approximately 60 μm wide near the fissure bottom but gradually widening to double this width near the fissure opening, and up to 200 μm wide in grooves, while underlying enamel had a low and almost constant F level. In this respect fissure and groove enamel resembled smooth surface enamel. The F concentration fluctuated along the surface layer, reaching maximum values ranging from 1,800 to 4,200 ppm in 5 non–carious fissures. Incipient caries in fissure enamel usually but not always resulted in an increase in F in the outer layer, the F maximum values in 5 such samples ranging from 1,900 to 7,200 ppm. F maximum values in outer enamel were higher in 7 samples showing advanced caries, 2,700–10,000 ppm. The lesion subsurface body usually showed normal F values, as did carious dentine in the advanced lesions. The variable characteristics of the outer layer in sound fissure enamel are likely to be the result of a developmental process rather than environmental influences. The fact that we normally failed to find increased F concentrations in subsurface carious fissure enamel or in underlying carious dentine suggests that F does not diffuse into the deep part of fissure lesions, and probably has minimal effect on slowing the progress of such lesions, a suggestion in accord with clinical findings on the F effect on fissure caries.
Reliability of a New Caries Diagnostic System Differentiating between Active and Inactive Caries Lesions
Authors: Nyvad B. , Machiulskiene V. , Baelum V.
Published: April 2003

Current scoring systems for dental caries do not consider the dynamic nature of the disease. The aims of the present study were to describe a new set of clinical caries diagnostic criteria which differentiate between active and inactive caries lesions at both the cavitated and non–cavitated levels and to evaluate the reliability of this criteria system in a population with high caries experience. Ten diagnostic codes were defined: 0 = sound; 1 = active (intact); 2 = active (surface discontinuity); 3 = active (cavity); 4 = inactive (intact); 5 = inactive (surface discontinuity); 6 = inactive (cavity); 7 = filling; 8 = filling with active caries; 9 = filling with inactive caries. Distinction between active and inactive caries lesions was made on the basis of a combination of visual and tactile criteria. The inter– and intra–examiner reliability was assessed through repeated examinations of 50 children by 2 recorders over a period of 3 years. The percentage agreement of caries diagnoses varied between 94.2 and 96.2%. The kappa values ranged between 0.74 and 0.85 for intra–examiner examinations and between 0.78 and 0.80 for inter–examiner examinations; 81.6% of all misclassifications involved non–cavitated caries lesions. Disagreement between sound surfaces and non–cavitated active or non–cavitated inactive lesions (31.3 and 31.2%, respectively) was more common than disagreement between non–cavitated active and non–cavitated inactive lesions (10.6%). The probability of reconfirming a sound, non–cavitated active or non–cavitated inactive caries lesion – given that the surface was diagnosed as either sound, non–cavitated active or non–cavitated inactive at the first examination – was 98.0, 68.7 and 72.5%, respectively. The results show that the use of a new set of clinical caries diagnostic criteria based on activity assessment can be performed with a high reliability, even when non–cavitated diagnoses are included in the criteria system.
Inhibitory Effect of Antibacterial Resin Composite against Streptococcus mutans
Authors: Tanagawa M. , Yoshida K. , Matsumoto S. , Yamada T. , Atsuta M.
Published: April 2003

Dental resin composites with antibacterial activity may be useful for preventing the secondary caries frequently seen around restorations. Three types of silver–supported antibacterial materials (Novaron, Amenitop and AIS) inhibited the growth of the major oral pathogen Streptococcus mutans. Minimum inhibitory amounts in suspensions of Novaron, Amenitop and AIS against S. mutans were 40, 30 and 400 μg/ml, respectively. These antibacterial materials were incorporated into TEGDMA–UDMA–based light–activated resin composite, and the antibacterial activities of these composites were examined. Composites incorporating 5 wt% (N–5) or more of Novaron and 7 wt% (AM–7) or more of Amenitop inhibited the growth of S. mutans, whereas composites incorporating up to 10 wt% of AIS did not. No significant difference in either compressive or flexural strength was observed between the control and N–5 composites after 1 day and 6 months of storage in water. However, for AM–5 composite, there was a significant difference in either strength parameter between the two immersion periods. There was no or extremely little release of silver ions from the N–5 and AM–5 composites after 1 day or 6 months of immersion in water. These results indicated that a light–activated resin composite incorporating silver–supported antibacterial material such as Novaron may be clinically useful due to its inhibitory effect against S. mutans and favorable mechanical properties.
Dyract versus Tytin Class II Restorations in Primary Molars: 36 Months Evaluation
Authors: Marks L.A.M. , Weerheijm K.L. , van Amerongen W.E. , Groen H.J. , Martens L.C.
Published: April 2003

Due to the changed treatment approach of proximal caries and the amalgam controversy, clinicians are in search for new materials. The aim of the present study was to compare amalgam with an adhesive material in deciduous molars in a clinical, split–mouth design study. At baseline 30 polyacid modified composite (Dyract®) and 30 amalgam (Tytin®) restorations were placed in primary molars, of which 24 and 17 could be evaluated after 24 and 36 months, respectively. Modified USPHS criteria were used for clinical evaluation every 6 months. Annual bite–wing radiographs were taken for evaluation of recurrent caries and cervical gap formation. In the present study, for Dyract as well as for Tytin restorations, low rates of recurrent caries were found, while Dyract restorations showed a better marginal adaptation and surface texture compared to Tytin restorations. In the Dyract group more radiolucencies were found at baseline. In both groups no patient complaint or pain was reported related to the radiolucencies. After 3 years the colour of Dyract was not comparable to the original. For Dyract no excessive wear was noticed compared to enamel. During the study one Dyract (recurrent caries: 18 months) and two Tytin (pulpal aetiology: 6 months, recurrent caries: 36 months) restorations had to be replaced. Even though the restorations were placed in caries risk children, at the 36 months’ evaluation of this clinical study, the results indicate that Dyract can be an alternative for Tytin in the primary dentition.
Powdered Milk Micellar Casein Prevents Oral Colonization by Streptococcus sobrinus and Dental Caries in Rats: A Basis for the Caries–Protective Effect of Dairy Products
Authors: Guggenheim B. , Schmid R. , Aeschlimann J-M. , Berrocal R. , Neeser J.-R.
Published: April 2003

Three animal studies were performed to investigate the influence of the macromolecular structure of milk casein on caries incidence and the possible ecological changes of the oral microbiota by such casein fractions. Towards this end, rats were infected with mixed bacterial suspensions of Streptococcus sobrinus OMZ 176 and Actinomyces viscosus Ny1. Various milk protein fractions were incorporated into carefully balanced powdered cariogenic diets to constitute the sole major protein component. Diets containing micellar casein had a pronounced and highly significant effect on almost all clinical and microbiological parameters examined. Both the formation of advanced dentinal fissure (B) and smooth surface (E) caries lesions was inhibited by diets containing micellar casein; this caries–inhibiting effect appeared to be due mainly to modifications within the plaque microbiota. The proportion of S. sobrinus in the oral cavity of rats was reduced (73–80%) by micellar casein–containing preparations, whereas the A. viscosus population was increased. Both these microbiological parameters were always negatively correlated. This appears to be the first example of a food component other than dietary sugars, selectively modifying the composition of the dental plaque microbiota of rats in such a way as to reduce its pathogenic potential. It also demonstrates the importance of establishing a molecular basis for the role of food components, which prove to be beneficial to oral health.
Prevalence of Dental Caries in Latvian 11– to 15–Year–Old Children and the Enhanced Diagnostic Yield of Temporary Tooth Separation, FOTI and Electronic Caries Measurement
Authors: Deery C. , Care R. , Chesters R. , Huntington E. , Stelmachonoka S. , Gudkina Y.
Published: April 2003

The aim of this study was to test the feasibility of employing clinical visual examination at the D1 (enamel and dentine caries) diagnostic threshold, fibre–optic transillumination (FOTI), elective temporary tooth separation (ETTS) and electronic caries measurement (ECM) in the environment of an epidemiological study or clinical trial. It also aimed to compare the diagnostic yield of these diagnostic aides and methods. The sample consisted of 182 Latvian children, mean age 13.3 years (range = 10.6–15.7). For 12–year–old subjects the mean D3MFS was 10.58 (SD 6.05) and the mean D1MFS was 19.97 (SD 10.47). The additional diagnostic yield from FOTI examination of approximal sites was 40.0% at the D1 threshold. The additional apparent yield for ETTS was 52.8% at the D1 threshold. ETTS detected 38.3% more carious surfaces than FOTI at the D1 threshold. Conversely 57 surfaces thought to be carious on FOTI examination were judged sound following ETTS. Although the ECM appeared practical to use, it broke early in the trial and the results obtained prior to breakdown appeared inaccurate. In conclusion, all diagnostic methods were feasible under the conditions of an epidemiological study or clinical trial.
Two and a Half–Year Outcome of Caries– Preventive Programs Offered to Groups of Children in the Solntsevsky District of Moscow
Authors: Ekstrand K.R. , Kuzmina I.N. , Kuzmina E. , Christiansen M.E.C.
Published: April 2003

This study examined the 2.5–year outcome of preventive programs – based on the Nexö method – offered to three groups of children from Solntsevsky, a district of Moscow. Study group A consisted of 45 3–year–olds, study group B of 50 6–year–olds, and study group C of 50 11–year–olds. A similar number of children were selected as control groups and they followed the normal dental service provided by the local Health Service System in the district. The caries–preventive programs offered to the study groups were based on: (1) education of the child, parents and teachers in the caries disease, (2) training in toothbrushing. In addition, the children in study groups B and C were offered professional plaque removal, applications of sodium fluoride (2%) and sealant applications according to individual needs. The children in groups B and C were clinically examined in March 1994 (baseline) after 1 and 2.5 years, respectively. Because of the age of the children in group A, these children were only examined once, after the study had been completed. After 2.5 years the children in all three study groups had improved their oral health status significantly compared to the children in the control group. The caries experience among the children in study group A was about half of that observed among children in the control group (4.91 def–s versus 8.60 def–s). The program was highly effective in controlling dental caries in the permanent dentition among the children in the study groups, who finished with a mean DMF–S of 0.28 (group B) and 3.12 (group C) compared to 2.24 and 6.35 among the children in the corresponding control groups. Nearly all the children used fluoridated toothpaste. The mean number of visits to the clinic decreased from year 1 to year 2 (5 versus 3.4 in study group B and 4.5 versus 3.3 in study group C). In conclusion, the preventive programs were highly effective with regard to improving the level of oral hygiene, and thereby reducing or even controlling the plaque–induced disease activity.
Some Factors Associated with the Caries Decline among Norwegian Children and Adolescents: Age–Specific and Cohort Analyses
Authors: Birkeland J.M. , Haugejorden O. , Ramm von der Fehr F.
Published: April 2003

The purpose of this study was to evaluate factors related to the caries decline in children between 1966 and 1983. The decline started in the late sixties for the 8– to 11– and the 17–year–olds, and after 1971 for the remaining age groups. Regression analyses confirmed a significantly different start of the decline. Fluorides in school–based programmes, lozenges, and toothpaste, as well as education and sale of antibiotics were significantly (p≤0.01) related to the caries decline in partial correlation analyses. Fluoride toothpaste was only significantly related to the decline in the last part of the period of observation. Supervised fluoride rinsing and brushing programmes at school may explain most of the decline before 1971. The later decline may be related to all fluoride agents and to education. Use of fluorides and other preventive efforts aimed at pre–school children may have contributed to the continual decline in the number of fillings in the permanent teeth of the youngest cohorts.
Parental Smoking Practices and Caries Experience in Pre–School Children
Authors: Williams S.A. , Kwan S.Y.L. , Parsons S.
Published: April 2003

Voluntary and involuntary smoking influence general health. Links between voluntary smoking and oral health are confirmed for periodontal diseases and oral cancer/precancer. Since recent reports have suggested an association between parental smoking and caries experience in young children, this study aimed to explore varying patterns of parental smoking, adjusted for social class, with caries prevalence, using data derived from the UK National Diet and Nutrition Survey (1995). Data analysis was confined to 749 children aged 3.0–4.5 years, to avoid confounding effects of unerupted teeth. Bivariate analysis indicated that the prevalence of maternal rather than paternal smoking was significantly related to caries and substantially attenuated social class differences. The reported number of cigarettes smoked was not important. To compensate for the association between social class and maternal smoking, data were dichotomised by social class (manual/non–manual). With caries prevalence as the dependent variable, logistic regression analysis recorded maternal smoking as a significant independent variable in each case, with odds ratios of 1.55/1.96, respectively. The process was repeated for the combined dataset, using the more extensive (six) social class categories. This further analysis yielded an odds ratio for maternal smoking of 1.54 compared with 1.46 for social class. Nutrition status (as growth parameters) and dietary intake (as household spending on confectionery) were not significant independent variables in these equations. The rationale for these findings is discussed. Further research is required to determine mechanisms underlying these observations. It is concluded that maternal smoking is a significant factor to be considered as an additional risk indicator beyond social class when predicting caries risk in young children.
Occlusal Caries Detection with KaVo DIAGNOdent and Radiography: An in vitro Comparison
Authors: Shi X.-Q. , Welander U. , Angmar-Månsson B.
Published: April 2003

A new laser fluorescence method, KaVo DIAGNOdent, was tested with respect to reproducibility and validity and compared with radiography regarding accuracy in the detection of occlusal caries. Seventy–six extracted premolar and molar teeth were measured twice with DIAGNOdent under both wet and dry conditions, at an interval of 2 weeks. Conventional film radiographs were exposed. Microradiographic analysis of sections of the teeth served as the gold standard. Intra–class correlation coefficient and Pearson’s correlation coefficient were used to assess the reproducibility and the validity of the method, respectively. The influence of time and varying humidities on DIAGNOdent readings were analysed by two–way repeated measure ANOVA. ROC curves were plotted for DIAGNOdent readings and radiographic registration of caries by 6 observers, and the areas under the curves were compared using Student’s t test. Under both wet and dry conditions, the reproducibility of the DIAGNOdent method was excellent: R = 0.97 and 0.96, respectively. The diagnostic accuracy of DIAGNOdent was significantly better than that of radiography (p≤0.001). In this in vitro study of detection of occlusal caries, the diagnostic performance of the DIAGNOdent method was superior to that of radiography.
Value of Bite–Wing Radiographs in a Clinical Epidemiological Study and Their Effect on the DMFS Index
Authors: Poorterman J.H.G. , Aartman I.H.A. , Kieft J.A. , Kalsbeek H.
Published: April 2003

The aim of this study was to determine, for different age groups, the additional value of bite–wing radiographs compared to the clinical information, and to calculate the subsequent effect on the DMFS index. Subjects were 14, 17, 20, 23 years old, or in the age groups 25–34 and 35–54, who participated in a clinical epidemiological survey. After obtaining consent, bite–wings were taken of approximately 25% of the participants (n = 663). The extra diagnostic yield of the bite–wings varied between 163 and 700% for approximal dentine caries diagnosis of untreated surfaces, and between 233 and 593% for inadequate restoration judgement for filled surfaces. The DS score went up by about 20–98%, whereas the DMFS index increased between 1 and 12%, resulting in a radiographic correction factor of 1.01–1.12. In conclusion, the considerable increase in the prevalence of approximal dentinal lesions and inadequate restorations for all age groups results in higher numbers of surfaces in need of treatment, but is not accompanied by a significant increase in DMFS scores.
Ten–Year Incidence of Dental Caries in Adult and Elderly Chinese
Authors: Luan W.-M. , Baelum V. , Fejerskov O. , Chen X.
Published: April 2003

Only very few longitudinal studies on dental caries are available in adults and elderly. Therefore, the aim of the present study was to describe the patterns of lesion progression in a group of adult and elderly Chinese followed over a 10–year period of time. In 1984, 587 persons aged 20–80 years were examined and by 1994, 440 of these were still available and re–examined by the same two examiners. All restorations, periodontal conditions and dental caries were recorded for all teeth and surfaces. Only caries data are reported here. Dental caries on coronal surfaces was classified as sound, non–cavitated, cavitated without or with pulp involvement or filled. On root surfaces, lesions were classified as sound, active caries or restored. Prior to analysis of the data, a series of drop–out analyses was carried out showing that most of the drop–outs were above 60 years of age at baseline, and death of participants was the major drop–out reason. A total of 2,114 teeth were lost, 36% of which had a deep dentin lesion at baseline. The distribution of persons according to number of new lesions/restorations over 10 years was highly skewed in all age groups, the prevalence increasing with age. Molars had the highest risk of becoming carious/restored over the 10–year period, and a remarkably low proportion of teeth had the same caries diagnosis after 10 years, indicative of lesion progression. When comparing the 1984 DFT/DMFT with the figures for 1994, there were no statistically significant differences indicating that the period and cohort effects cancel out each other. There was a significant increase with age of the number of new DFT. It can be concluded that dental caries is a major health problem in contemporary adult and elderly Chinese populations, and that caries incidence increases with old age.
The Anticariogenic Effect of Amine Fluorides on Streptococcus sobrinus and Glucosyltransferase in Biofilms
Authors: Shani S. , Friedman M. , Steinberg D.
Published: April 2003

Dental caries is a chronic infectious disease caused by the accumulation of bacterial plaque (biofilm) on tooth surfaces. Antibacterial agents, in addition to other preventive measures, can control dental plaque accumulation. Amine fluorides (AmF) are known anticaries agents for over 30 years. The purpose of our study was to assess the adsorption and desorption of AmF to experimental dental biofilm and to evaluate the effect of AmF on Streptococcus sobrinus 6715 and glucosyltransferase (GTF) activity in experimental dental biofilms. The experimental plaque model used in this study consists of hydroxyapatite beads coated with human saliva (sHA), followed by adsorption of S. sobrinus and synthesis of in situ polysaccharides. Our results show that the viability of S. sobrinus in biofilm decreased as the concentration of AmF and chlorhexidine (CHX) increased. The concentration of AmF and CHX required to kill S. sobrinus adherent to sHA is about 100 times greater than the concentration required to kill the same amount of planktonic bacteria. Adsorption of AmF to surfaces was more than 90% and the desorption of AmF from our experimental model was limited. Pre–adsorption of AmF on the surface increased adhesion of S. sobrinus but also resulted in surface killing of the adsorbed bacteria. At low concentrations AmF increased GTF activity in solution by about 10%, but at concentrations above 0.1 mM it inhibited GTF activity. Inhibition of GTF on the surface required about 100 times more AmF than in solution. Our results show that AmF retains its anticariogenic effects in solution and in biofilm systems.
Evaluation of Carisolv™ for the Chemo–Mechanical Removal of Primary Root Caries in vivo
Authors: Fure S. , Lingström P. , Birkhed D.
Published: April 2003

The objective of this study was to evaluate a new chemo–mechanical method (Carisolv™) for the removal of primary root caries in vivo in terms of efficiency, treatment time and patient perception. Thirty–eight patients participated in an open, randomised and controlled study. Of the 60 root carious lesions included, 34 were randomised for chemo–mechanical treatment and 26 for drilling. A within–subject comparison was used whenever the patient had two cavities, which was the case for 22 subjects. All the Carisolv–treated cavities became caries free, as did all but one of those treated with drilling, as judged by an independent examiner. Only 4 of 34 patients asked for anaesthesia in the Carisolv group compared with 6 of 26 patients in the drilling group. Of those who did not use anaesthesia, 12 individuals in the drilling group experienced some pain compared with none in the chemo–mechanical group (p<0.001). The mean treatment time for the Carisolv method was 5.9 ± 2.2 min, compared with 4.5 ± 2.0 min for drilling; time for anaesthesia excluded (p<0.05). No negative reactions or adverse effects were recorded during the study. All 55 teeth examined in the 1–year follow–up were found to be sensitive using an electric pulp tester, and there was no difference regarding the condition of fillings between the lesions treated with Carisolv and drilling. It can be concluded that root caries can be effectively removed using the Carisolv method. The longer treatment time was compensated by less need for anaesthesia.
Ultrasonication as a Method to Study Enamel Demineralisation during Acid Erosion
Authors: Eisenburger M. , Hughes J. , West N.X. , Jandt K.D. , Addy M.
Published: April 2003

The aim of this study was to use ultrasonication as a method to measure subsurface demineralisation of enamel. Polished human enamel samples with surface profiles within ±0.3 μm were divided into 6 groups of 10 specimens. The groups of specimens were exposed to 0.3% citric acid (pH 3.2) for 30 min, 1, 2, 3 or 4 h. The depths of the resulting lesions were measured using a profilometer. A control group was stored in water for 4 h. Ultrasonication in water was performed on the specimen groups for 5, 30, 120, 240 and 480 s with profilometric measurements at each time point. The depth of the erosion increased linearly with the exposure time. Most of the additional loss of enamel occurred with the 5–second ultrasonication. The 30–min and 1–hour erosion lesions were further deepened by approximately 1 μm with 5 s of ultrasonication. The 2–, 3– and 4–hour lesions were deepened by 2–4 μm with 5 s of ultrasonication. There were no changes in the control group. It is concluded that ultrasonication removed softened enamel from the surface of the eroded enamel. Ultrasonication together with accurate measurement of lesion depth by profilometry offers a useful method for studying the depth of enamel softening associated with erosion.
Caries Prediction by Multiple Salivary Mutans Streptococcal Counts in Caries–Free Children with Different Levels of Fluoride Exposure, Oral Hygiene and Sucrose Intake
Authors: Petti S. , Hausen H.W.
Published: April 2003

The aims of this study were to assess whether multiple salivary mutans streptococcal (ms) counts have a higher predictive power than a single one, and whether the predictive power of the test is different at different levels of fluoride exposure, oral hygiene and sucrose consumption. Three salivary ms tests were performed at 3–month intervals (positive test: salivary ms ≥5×105 cfu/ ml) on a sample of 304, initially caries–free, 6– to 7–year–olds. Plaque index was also assessed and the parents filled out a questionnaire concerning sucrose–containing eating events and fluoride exposure. Sensitivity, specificity and Youden's index (J) were used to compare the predictive power. Thirty–six percent of the children developed caries during the 2–year follow–up. The highest J value for a single ms test (the second) was 0.24 (sensitivity 29.1%, specificity 95.4%). The multiple ms test with the highest J value (0.29) was obtained by the dichotomies 0 vs. 1–3 positive tests (sensitivity 50.0%, specificity 79.9%) and 0–1 vs. 2–3 positive tests (sensitivity 31.8%, specificity 97.4%). The predictive power of the multiple test was passable for children with low fluoride exposure and high plaque index (sensitivity 57.4%, specificity 93.7%, J 0.51), while it was low for the other groups. Sucrose exposure did not significantly affect the predictive power of the ms test.sion.
Fluoride in Plaque Fluid, Plaque, and Saliva Measured for 2 hours after a Sodium Fluoride Monofluorophosphate Rinse
Authors: Vogel G.L. , Mao Y. , Chow L.C. , Proskin H.M.
Published: April 2003

Sodium monofluorophosphate (NaMFP) and sodium fluoride (NaF) are the two most common sources of fluoride used in currently marketed fluoride dentifrices. The purpose of this study was to investigate the effect of mouth rinses containing NaF or NaMFP on the concentrations of fluoride, or the MFP ion, in saliva, whole plaque, and plaque fluid. Twelve subjects abstained from tooth brushing for 48 h, fasted overnight, and then rinsed 1 min with 12 mmol/l (228 ppm [μg/g] F) NaF or NaMFP in the morning. Before the rinse and at 30, 60 and 120 min afterwards, upper and lower molar and premolar plaque samples and whole saliva samples were collected. Aliquots of plaque fluid and centrifuged saliva were obtained from these samples, and the whole plaque residue acid extracted. The F and MFP concentrations were then measured in these samples using ultramicro methods. For both rinses, a higher concentration of plaque fluid fluoride was found at lower molar sites while the reverse was true for the whole plaque fluoride. Furthermore, for both rinses, plaque fluid, whole plaque, but not salivary, fluoride concentrations were above baseline at 120 min. Following the NaMFP rinse, a substantial amount of unhydrolyzed MFP was found in plaque fluid and saliva. Although there was a very large range in these measurements, fluoride in plaque fluid (excluding fluoride in unhydrolyzed MFP) and whole plaque were significantly (p<0.05) greater after the NaF rinse at all time periods. In saliva, the NaF rinse produced a statistically significant greater salivary fluoride (excluding fluoride in unhydrolyzed MFP) only at 60 min. The lack of a clear correlation between these measurements and clinical studies suggest a novel mechanism may enhance the effectiveness of NaMFP dentifrices.
Biochemical Composition and Cariogenicity of Dental Plaque Formed in the Presence of Sucrose or Glucose and Fructose
Authors: Cury J.A. , Rebelo M.A.B. , Del Bel Cury A.A. , Derbyshire M.T.V.C. , Tabchoury C.P.M.
Published: April 2003

The composition of dental plaque formed in the presence of sucrose or glucose and fructose and its relation to cariogenicity was evaluated. Twelve adult volunteers took part in this crossover study done in three phases of 28 days each. For each phase, an acrylic resin appliance containing four human dental enamel blocks was constructed for the volunteers. Solutions containing 20% sucrose or 10% glucose + 10% fructose were dripped onto the enamel blocks 8 times a day, while in the control group no solution was used. Enamel surface and cross–sectional microhardness results showed that dental plaque formed in the presence of sucrose was more cariogenic than that formed in the presence of glucose + fructose (p<0.05). The concentration of alkali–soluble carbohydrates in dental plaque was higher in the sucrose group than in the control and glucose + fructose groups (p<0.05). Although concentrations of Ca, P and F were lower in plaque formed in the presence of sucrose than glucose + fructose and the control, significant differences (p<0.05) were only observed in relation to control. The electrophoretic profile of the matrix proteins of dental plaque showed distinct patterns when it was formed in the absence or presence of the different carbohydrates. Although the results suggest that the high cariogenicity of dental plaque formed in the presence of sucrose can be mainly explained by the high concentration of insoluble glucans of its matrix, the low inorganic concentration and its protein composition may have some contribution.
Neuromuscular Remodeling and Myofiber Turnover in Rana pipiens’ Jaw Muscles
Authors: Alley K.E. , Omerza F.F.
Published: April 2003

Larval jaw myofibers in Rana pipiens degenerate during metamorphosis and are replaced by a second wave of myogenesis that provides for adult jaw function. Trigeminal motoneurons that innervate larval myofibers transfer their preterminal axons to these adult successors where they establish new motor endplates. Silver/acetyl-cholinesterase histochemistry was used to compare innervation patterns in the larval and adult jaw adductor muscles and to plot the time course over which these changes occur. Innervation patterns differ substantially on the pre- and postmetamorphic myofiber populations. Jaw myofibers in the tadpole were unique by virtue of their exceedingly high level of distributed and focal polyinnervation. Each myofiber was innervated by approximately 10 small, junctional zones, most containing multiple axons, diffusely distributed over the length excepting small junctional free zones at either end of the muscle. In juvenile frogs, immediately following redeployment, the replacement myofibers had a polyinnervation pattern that mirrors that observed in the larvae. However, by 12 weeks after metamorphosis there was a clear condensation of the end plates into multiple zones. Moreover, jaw myofibers in adult frogs had a reduced level of distributed and focal polyinnervation, less than 15% show signs of polyinnervation. The pattern of polyinnervation, axonal redeployment and myofiber degeneration is consistent with the hypothesis that the larval jaw muscles serve as a population of primary myofibers, ensuring survival of the trigeminal motoneurons through the prolonged period of larval development, while also providing a scaffold on which secondary jaw myofibers are constructed.
Effects of Static Electromagnetic Fields on Chick Embryo Pineal Gland Development
Authors: Jové Montserrat , Torrente Miguel , Gilabert Rosa , Espinar Auxiliadora , Cobos Pedro , Piera Verónica
Published: April 2003

The effects of static electromagnetic fields on the development of the chick embryo pineal gland were studied. A total of 144 fertilized White Leghorn eggs were sacrificed after 5, 10 and 15 days of incubation. The stage of development was determined in all embryos using the Hamburger and Hamilton method [J Morphol 49: 88–92, 1951]. The various morphometric parameters (diameter and distance of the pineal gland and its lumen) were measured on serial 7-μm-thick sections. The data were obtained in a morphometer and processed statistically. The intensities of the static electromagnetic fields were 18 and 36 mT. Control and exposed embryos were equally distributed and randomly assigned. After 5 days of incubation, 25% of embryos exposed to a static electromagnetic field of 18 mT had a more advanced stage of development than controls and embryos exposed to 36 mT. On the 10th and 15th day, embryos exposed to either 18 or 36 mT tended to be more developed than controls. In the morphometric study, results were similar for the controls and exposed embryos after 5 and 10 days of incubation. However, the values of the 15-day-old embryos exposed to static magnetic fields were lower than the values of the controls (p > 0.01). These differences were more pronounced in the embryos exposed to 36 mT. These results seem to indicate that static electromagnetic fields affect the development and growth of embryos unequally, and that their action can depend not only on the intensity of the static electromagnetic field, but also on the length of exposure and the organ which is developing. It may be interesting to use these data in ultrastructural and physiological studies.
Quantitative Analysis of Extracellular Matrix Proteins in Hypertrophic Layers of the Mandibular Condyle and Temporal Bone during Human Fetal Development
Authors: Sato Iwao , Sunohara Masataka , Sato Toru
Published: April 2003

A computer image analysis of immunostained extracellular matrix (ECM) proteins (collagen types I, II, III and V, fibronectin and tenascin) in hypertrophic layers in the mandibular condyle and temporal bone of human fetuses, which ranged in gestational age from 12 to 32 weeks, was performed. The percentage of cells positive for proliferating cell nuclear antigen (PCNA) increased in almost the same manner in each region. The level of PCNA was markedly elevated at 16 weeks. The percentage of PCNA-positive cells was low in temporal bone and in the bone-forming layer of the mandibular condyle at 24 weeks. Specific concentration patterns of proteins in the ECM were found at each stage of development. The extent of accumulation of fibrillar collagen and of fibronectin differed, while those of other proteins in the ECM, such as tenascin, osteocalcin and osteonectin, were similar at the two sites.
An in vitro Pathway from Embryonic Stem Cells to Neurons and Glia
Authors: Gottlieb David I. , Huettner James E.
Published: April 2003

Mouse embryonic stem (ES) cells can be induced to differentiate into neurons and glia in vitro. Induction protocols are straightforward and involve culture in the presence of retinoic acid. They result in an efficient conversion of undifferentiated ES cells to neural cells. Mature neurons produced have the key physiological, morphological and molecular properties of primary cultured neurons derived from the central nervous system. Most significantly, they form functional chemical synapses that utilize either glutamate, GABA or glycine as neurotransmitters. ES cell-derived glial cells also correspond well with their normal counterparts. During induction, ES cells undergo a series of developmental steps that resemble key stages in the early mouse embryo. This supports the hypothesis that the in vitro pathway is a valid model of the normal developmental pathway leading to neurons and glia. The in vitro system combines three experimental strengths. It is suitable for genetic manipulation, affords large numbers of cells and allows precise manipulation of the culture environment. It is thus suitable for a wide variety of mechanistic studies in the areas of neural development and cell biology.
Embryonic Stem Cell-Derived Haematopoiesis
Authors: Hole Nicholas
Published: April 2003

Embryonal stem (ES) cells are pluripotent cell types that in chimaeric mice can give rise to all cellular lineages. Early studies showed that they also had the potential to form mature erythrocytes following in vitro differentiation. In recent years ES cells have been demonstrated to be competent both to produce all haematopoietic lineages following in vitro differentiation and long-term repopulating haematopoietic stem cells. This review discusses the approaches that have been used to produce these haematopoietic cells and the nature of the haematopoietic stem cells that can be isolated. The utility of the system to both isolate genes involved in control of haematopoiesis and to assess their function following transgenesis is demonstrated. The prospectives for this field are then discussed in the context of recent developments in human ES cells and evidence of stem cell plasticity.
Leptin Expression during the Differentiation of Subcutaneous Adipose Cells of Human Embryos in situ
Authors: Atanassova P. , Popova L.
Published: April 2003

In this study, the immunocytochemical expression of leptin in the developing subcutaneous tissue of human embryos at 6–10 weeks of gestation was investigated using the avidin-biotin peroxidase method. Immunocytochemical staining for leptin was observed in the cytoplasm of the differentiating preadipose cells. The other cells present in the embryonal subcutis (mesenchymal cells differentiating into fibroblasts, fibrocytes, endothelial cells) were leptin-negative. The developing skin epithelium lying above it and the blood cells in the capillaries also did not express leptin. The results suggest that the leptin is produced by the developing fat cells from the beginning of lipidogenesis and differentiation. It possibly acts as a hormonal factor regulating the embryonal growth, development and body fat storage.
Intraepithelial Leucocytes in the Bovine Uterine Tube
Authors: Abughrien Badia M. , Dore Michael A.P. , McGeady Thomas A. , Fitzpatrick Eamonn
Published: April 2003

The epithelium of the uterine tube consists of ciliated cells and secretory cells. Basal cells are a third cell type observed in tubal epithelium and they are located principally in the basal part of the epithelium. The objectives of this study were to characterize these basal cells in normal and superovulated heifers and to determine whether they participate in the replacement of the ciliated and secretory cell populations. All heifers received cloprostenol (PG) to induce oestrus (day 0). Superovulated heifers received 24 mg pFSH at doses of 4.5, 3.5, 2.5 and 1.5 mg given twice daily. Control and superovulated heifers were slaughtered on days 1, 3, 5 and 7 of the oestrous cycle. Another group of normal cycling heifers was slaughtered on days 2–3 and 11–13 of the oestrous cycle and used for immunocytochemistry. Samples from ampulla, pre-isthmus and isthmus of the uterine tube were collected and processed for light and transmission electron microscopy. Quantitative examination by light microscopy showed that there was a significant difference in the number of basal cells between the regions of the heifers’ uterine tube. On the basis of ultrastructure two populations of basal cells were observed. One (type I) had a nucleus with much condensed heterochromatin and very sparse cytoplasmic organelles. The second cell (type II) had a nucleus with heterochromatin typically clumped around the nuclear envelope. Its cytoplasm contained many organelles including a number of lysosomes. The ultrastructural features of these cells were similar in all regions and at all days of the oestrous cycle examined. Immunocytochemistry revealed that type I basal cells were lymphocytes and type II basal cells were macrophages.
Secreted Proteins of the Oviduct
Authors: Buhi W.C. , Alvarez I.M. , Kouba A.J.
Published: April 2003

During late follicular development and estrus, the mammalian oviduct undergoes specific physiological and biochemical modifications which contribute to an optimization of the microenvironment for fertilization and early cleavage-stage embryonic development. These changes appear to be hormonally regulated by ovarian steroids, most importantly, estrogen. The hundreds of macromolecules found within the oviductal lumen are contributed by selective serum transudation and active biosynthesis and secretion from nonciliated epithelial cells. Recent studies have indicated temporal and regional (infundibulum, ampulla and isthmus) differences in steady-state levels of specific mRNAs and in de novo protein synthesis and secretion by the oviduct. One protein synthesized de novo, the estrogen-dependent oviductal secretory glycoprotein (OSP), has been shown to be unique to the oviduct and is conserved across a number of mammalian species. This protein associates with the zona pellucida, perivitelline space and vitelline or blastomere membrane of ovulated eggs and preimplantation embryos. OSPs have been shown to enhance sperm binding and penetration in oocytes and may regulate development in early preimplantation embryos. Other regulatory molecules, protease inhibitors, growth factors, cytokines, binding proteins, enzymes and immunoglobulins have been identified in the oviductal microenvironment. The identification and potential roles for oviduct-secreted proteins will be reviewed and discussed. Current research focuses on continued identification and characterization of specific oviductal proteins and a determination of the molecular basis of their interactions with the oocyte, sperm or embryo.
Marsupial Egg and Embryo Coats
Authors: Selwood Lynne
Published: April 2003

Egg and embryo coats of marsupials are reviewed. Marsupial eggs are enclosed by a zona pellucida, mucoid coat and an outer shell coat. An extra-cellular matrix coat that lines the zona pellucida also occurs in some species. The zona pellucida consists of three zona proteins (ZPA, ZPB, ZPC) with considerable similarity to those of eutherian mammals. The zona is thought to be the sperm receptor site and, in some species, but not others, is a barrier to polyspermy. Immunostaining, in situ hybridisation, histochemistry and electron microscopy indicate that the zona originates in the oocyte at the onset of oocyte growth. It changes greatly in shape during ovulation and early development and plays an essential role in blastocyst formation. The mucoid coat is an acid glycoprotein that is produced by non-ciliated cells at all levels of the oviduct and has been implicated in providing a barrier to polyspermy, nourishment of the embryo and an osmotically stable environment for the embryo. Its width varies widely in marsupials. The shell coat is secreted by the epithelia of the utero-tubal junction and upper uterus during oestrus and early cleavage. Evidence is provided for a second wave of secretion at bilaminar and trilaminar blastocyst stages. Shell-free embryos do not survive in vitro during bilaminar and early trilaminar blastocyst stages. Hatching from the shell coat occurs between 65 and 85% of the gestation period usually when the embryo is undergoing early somitogenesis. The extra-cellular matrix is secreted by the oocyte or by the cells of early cleavage stages and initially separates cells from the zona pellucida and from each other. It plays an essential role in blastocyst formation. The zona, mucoid and shell coats provide a framework for blastocyst construction and normal embryos do not form in their absence in some species.