bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of Dental Fluorosis in a European Country in Relation to the Fluoride Concentration of Drinking Water
Authors: Larsen M.J. , Kirkegaard E. , Poulsen S. 
Published: November 2010

Dental fluorosis among 456 14-16-year-old schoolchildren who had resided continuously since birth in their respective study areas was recorded using the Thylstrup and Fejerskov classification system. The children fell into four groups according to fluoride concentration of their drinking water: (1) less than or equal to 0.1 ppm; (2) 0.3-0.5 ppm; (3) 0.5-1.25 ppm; and (4) 1.26-2.0 ppm. It was found that the later in childhood the tooth was formed, the higher was the prevalence of dental fluorosis. The fluoride concentration in the drinking water affected the prevalence of dental fluorosis in all teeth except the lower incisors, which are formed very early in life. Apart from these teeth, the proportionate increase of dental fluorosis with increasing water fluoride concentration was almost the same for all tooth types. However, the actual amount of increase in the prevalence and degree of fluorosis was greatest among those teeth that formed later during childhood. The observed fluorosis is presumed to result from and reflect the drinking water habits in the population as well as the patterns of use of fluoride prophylactics.
Invited Review: Possible Mechanisms Involved in the Immunoregulation of Chronic Inflammatory Periodontal Disease
Authors: Seymour G.J. 
Published: November 2010

It is generally agreed that immunological mechanisms are involved in the pathogenesis of periodontal disease; however, regulation of these mechanisms has hitherto received scant attention. Regulatory net works exist at both a cellular and a molecular level. At the cellular level, the existence of helper (T4-positive) and suppressor (T8-positive) T lymphocytes, the expression of Class II major histocompatibility complex antigens, and the heterogeneity of macrophage subpopulations are central to an understanding of the regulatory mechanisms involved. It is only recently that studies of these separate components, in both humans and experimental animals, have begun to provide a basis for understanding the complex interactions occurring in periodontal disease. Studies using the human experimental gingivitis model have shown an immunoregulatory picture consistent with a controlled immunological reaction with an essentially normal T4:T8 ratio of 2.0. In con trast, studies utilizing cells extracted from adult periodontitis lesions have shown a reduced T4:T8 ratio (approximately 1.0) and an inability to respond in, or to stimulate, an autologous mixed lymphocyte reaction. Animal studies using athymic nude rats have supported the concept of a central role for T-cell control in periodontal disease and the possibility of an imbalance in this control with disease progression. These results are reviewed and areas of future research explored.
A Bacteriological Study of Rampant Caries in Children
Authors: Boue D. , Armau E. , Tiraby G. 
Published: November 2010

We undertook a microbiological study, in children, of dental plaque from sound surfaces or associated with rampant caries, both black-colored and unstained. Improved selective media allowed for the enumeration of bacteria belonging to specific genera or species present in plaque samples. A nearly similar bacterial distribution was found in both types of rampant caries. Aciduric flora, Streptococcus mutans, Veillonella, and Lactobacillus predominated in plaque over the lesions, whereas extracellular polysaccharide-producing streptococci other than S. mutans, as well as Actinomyces, were more abundant in plaque from sound surfaces. However, more lactobacilli and Actinomyces were recovered from pigmented lesions than from the unstained ones. These findings suggest that the microbial flora associated with black-pigmented lesions did not strongly differ from that observed over unstained caries lesions.
Morphometric Analysis of Teeth with Inflamed Pulp
Authors: Warfvinge J. 
Published: November 2010

The most common method of evaluating pulp tissue reactions to injury is by a qualitative assessment of pulp tissue alterations. This evaluation method is subjective and difficult to quantify; stereological methods are more suitable, for they can quantify important tissue components, and so more objectively describe pulp tissues. This study compares a morphometric and a descriptive method of classification for pulp tissue analysis by using 15 teeth with inflamed pulp tissue, and 12 teeth experimentally pulp-capped with calcium hydroxide. Morphometric analysis allowed for volumes of remaining dentin, pulp tissue, inflamed pulp tissue, and reparative dentin to be calculated. In addition, volume densities of polymorphonuclear and mononuclear leukocytes, odontoblasts, fibroblasts, erythrocytes, vessels, and residual tissue were calculated for comparison among different experimental teeth. The morphometric method provided a quantitative description of tissue reactions. The descriptive method of classification was adequate when inflamed tissue subjacent to the cavity was evaluated, but was less precise than the morphometric method in describing reactions deeper in the tissue. The descriptive method could delineate the amounts and types of inflammatory cells only in non-quantified terms, while the morphometric method could quantify and locate them. It also yielded a quantified evaluation of the healing sequence of experimentally pulp-capped teeth. In conclusion, a morphometric method can yield more quantitative data on pulp tissue reactions than can a descriptive method of classification.
The Relationship Between Test Methodology and Elastic Behavior of Composites
Authors: Braem M. , Davidson C.L. , Vanherle G. , Van Doren V. , Lambrechts P. 
Published: November 2010

Comparisons were made of the Young's moduli obtained with tests that impose static, low-frequency, or high-frequency elastic deformations on dental composite systems. The frequency of the imposed stress was reflected in the absolute value of Young's modulus. However, the values obtained at different test frequencies could be compared and understood by taking into account this frequency dependence. It was thus found that the composite structure largely determined the type of reaction to the imposed stress. The fundamental period test permitted the greatest differentiation in the elastic behavior of the investigated composites.
Clinical Application of Topical Fluoride Products- Risks, Benefits, and Recommendations
Authors: Lecompte E.J. 
Published: November 2010

This portion of the symposium discusses the various methods of professionally applying high-concentration topical fluoride products and their risks and benefits. Numerous recent investigations in this area of research are reviewed and discussed. Data from these research investigations point to the need for care when high-potency F products are used, especially in young children. Oral-retained F doses following four-minute topical application procedures ranged from 10 to 31 mg when no suction devices or patient expectoration was utilized. Following the use of suctioning devices, oral-retained F doses ranged from 6 to 12 mg, a clinically unacceptable level. Following the use of suctioning devices plus patient expectoration, the oral-retained F doses were reduced to from 2 to 7.5 mg, depending on type of F product and application system. The following recommendations for topical application of high-potency F products are made: (I) No more than 2 g of gel per tray or approximately 40% of tray capacity should be dispensed. Even more conservative amounts should be considered for small children. (2) Because patients may have the need to swallow during a four-minute topical application procedure, the use of a saliva ejector during the procedure is recommended. (3) Following the four-minute application procedure, the patient should be instructed to expectorate thoroughly for from 30 sec to one min, regardless of whether high-speed suction is utilized. Expectoration is probably the single most effective way of reducing orally retained fluoride. (4) When utilizing custom individually fitted trays for patients requiring daily or weekly application of a high-F-concentration product, utilize only 5 to 10 drops of product per tray.
Time-dependent Dissolution of Amalgams into Saline Solution
Authors: Ferracane J.L. , Mafiana P. , Cooper C. , Okabe T. 
Published: November 2010

The dissolution of mercury, silver, and copper from polished and unpolished surfaces of low- and high-copper amalgams into saline was investigated with respect to time via atomic absorption spectrophotometry. Greater amounts of mercury and silver were released from unpolished than from polished surfaces. Ion release was greatest during the first three hours after trituration of all amalgams. The rate of dissolution of ions from amalgams into saline is considered to be very low once the amalgam has set, and is probably inhibited by the formation of a surface film formed during immersion.
Bacterial Endotoxin Inhibits Migration, Attachment, and Orientation of Human Gingival Fibroblasts in vitro and Delays Collagen Gel Contraction
Authors: Pitaru S. , Soldinger M. , Madgar D. , Metzger Z. 
Published: November 2010

The purpose of this study was to assess the effect of endotoxin adsorbed to dental surfaces and to collagen type I on the migration, attachment, and orientation of human gingival fibroblasts (HGF). Transversely cut porcine tooth root slices (RS), 200 μm thick, were prepared. Half of the RS obtained were partially demineralized in EDTA. Half of the demineralized and non-demineralized RS were incubated with 400 μg/mL of endotoxin for 24 hr, whereas the other half were maintained in PBS and served as controls. Experimental and control RS were placed on confluent layers of HFG and cultured for six days. Cell migration toward and cell attachment to the periphery of the RS and the formation of oriented cell sheets were assessed by means of photographic techniques. Additionally, six-day-old cultures were fixed and processed for SEM observation. In separate experiments, the effect of endotoxin on cell attachment to collagen type I and on contraction of three-dimensional collagen gels was assessed. It was found that: (i) bacterial endotoxin inhibited migration and attachment of HGF to both demineralized and non-demineralized cementum and interfered with the development of oriented cellular structure ; (ii) the inhibitory effect was significantly more pronounced for non-demineralized than for demineralized cementum; (iii) the morphology of HGF attached to endotoxin-treated dental surfaces was altered compared with that of their controls; and (iv) bacterial endotoxin inhibited cell attachment to collagen type I and delayed the contraction of collagen gel.
Pharmacological of an Intra-oral Fluoride-releasing Device in Adolescents
Authors: Kula K. , Kula T. , Davidson W. , Parker E. 
Published: November 2010

The purpose of this study was to quantify fluoride (F) concentrations in body fluids of adolescents wearing two intra-oral fluoride-releasing devices (IFRDs) designed to release 0.10 mg Fiday. Fluoride concentrations were determined potentiometrically. No significant increases occurred in urine or serum F concentratiotis during the 26-week device phase. Elevated salivary F concentrations were maintained throughout the device phase when broken or depleted IFRDs were replaced. However, salivary F concentrations returned to pre-device phase values, by 26 weeks when the original IFRDs were maintained. These findings suggest that IFRDs can significantly elevate salivary F concentrations of adolescents without significant elevations in systemic F concentrations.
Comparison of the Effects of Fluoride and the Ionophore Nigericin on Acid Production by Streptococcus mutans and the Resultant in vitro Enamel Demineralization
Authors: Van Loveren C. , Fielmich A.M. , Ten Brink B. 
Published: November 2010

In an in vitro demineralization experiment with a plaque of S. mutans C180-2 over enamel, the effect of 0.5 mmol fluoride/L was compared with that of 10 nmol nigericin/L. Since the effects of both substances on the acid production in a dense cell suspension were of the same magnitude, and since nigericin did not affect the enamel solubility, the present demineralization experiment may differentiate between the effect of fluoride on bacterial metabolism alone and the combined effect of fluoride on both the bacterial metabolism and enamel solubility. In our experiments, the effect on bacterial metabolism accounted for 75% of the caries-inhibiting effect of fluoride. Microradiographic data showed subsurface lesions in the control and nigericin group and a slight surface-softening in the fluoride group. In addition, the effects of fluoride and nigericin on the cellular internal pH during glycolysis were studied. Analysis of these data suggested that glycolysis was inhibited when the intracellular pH reached about pH 5.2, which supports the view that acidification of the cell cytoplasm is a mechanism by which fluoride inhibits glycolysis.
Adherence of Treponema denticola to Modified Hydroxyapatite
Authors: Cimasoni G. , McBride B.C. 
Published: November 2010

Small samples of hydroxyapatite (HA) beads were coated with 10 μL of either saliva, serum, human crevicular fluid, or a preparation of lysosomal enzymes from human polymorphonuclear leucocytes (PMN), before being added to suspensions of Treponema denticola. The beads were then observed with the scanning electron microscope. Abundant T. denticola were found to adhere to HA or HA coated with saliva, serum, or crevicular fluid. Coating the beads with lysosomal enzymes consistently prevented the adhesion of T. denticola. Adhesion of treponemes to hard surfaces, modulated by enzymes from PMNs, could represent a new virulence factor for these bacteria.
Age Changes in Secretory Function of Male and Female Rat Parotid Glands in Response to Methoxamine and Pilocarpine
Authors: Inanaga A. , Habu T. , Tanaka E. , Taniguch T. , Nishiura T. , Ishibashi K. , Naruse S. , Abe K. 
Published: November 2010

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of both parotid glands of male and female rats at weekly age intervals from three to 10 weeks, and at 3.5, 8, and 15 months of age. It was analyzed for the concentrations of protein, potassium, calcium, inorganic phosphate, and for amylase activity. The types of protein were determined electrophoretically, and an amino acid analysis of the total protein was also carried out. The wet weights of the glands increased substantially up to eight weeks of age, then reached almost plateau values, and finally tended to decrease at 15 months of age in both sexes. The salivary volumes secreted in response to methoxamine and pilocarpine were positively correlated with the parotid gland weights in both sexes. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the salivary flow rates only at relatively low rates of flow. The amylase activity was positively correlated with the concentration of protein, independent of the nature of the stimulus, age, and sex. With methoxamine as a stimulus, the amylase activity was positively correlated with the concentration of calcium, independent of age and sex. The types of protein and amino acid concentrations were independent of the nature of the stimulus, age, and sex up to 15 months of age. However, in parotid saliva of several rats at 8 and 15 months of age, unusual proteins were observed electrophoretically, independent of the nature of the stimulus and sex.
Comparison of Fluoride Concentrations in Unstimulated whole Saliva Following the Use of a Fluoride Dentifrice and a Fluoride Rinse
Authors: Zero D.T. , Fu J. , Espeland M.A. , Featherstone J.D.B. 
Published: November 2010

Recent evidence has suggested that the cariostatic effects of topical fluoride (F) are related to the presence of low concentrations of ionic F in the oral environment. The purpose of this study was to compare the retention of F in the oral environment over 24-hour periods after the use of a F dentifrice or a F rinse. Groups of ten consenting adult subjects (age 18-52 years) brushed and/or rinsed (B/R) in a standardized manner twice per day in the morning (AM) and before bed (PM) with either a placebo dentifrice (8 ppm F), NaF dentifrice (1100 ppm F), or NaF rinse (225 ppm F). Experiments were performed with placebo dentifrice only (PD); F dentifrice only (FD); F dentifizce followed by F rinse (FD/FR); placebo dentifrice followed by F rinse (PD/FR); and F rinse followed by placebo dentifrice (FR/PD). Unstimulated whole saliva samples were collected at baseline and then at 0, 15, 30, and 45 min, 1, 2, and 8 hr after B/R in the AM, after B/R in the PM and upon rising the following morning. Salivary flow rate and F were determined for each sampling interval. The results of this study suggest that: (1) F rinse may be a more effective way of delivering topical F than F dentifrice; (2) based on F retention, the combination of FD/FR was not more effective than FR only (PD/FR); (3) older individuals with gingival recession retained higher F levels; and (4) bedtime F application resulted in longer F retention than did daytime application, which may have important implications for enamel remineralization.
The Acute Effects of Smokeless Tobacco on Transport and Barrier Function of Buccal Mucosa
Authors: Tobey N.A. , Schreiner V.J. , Readling R.D. , Orlando R.C. 
Published: November 2010

The acute effects of smokeless tobacco (ST) on buccal mucosal transport and barrier function were studied by means of in vivo and in vitro techniques. In humans, in vivo exposure to 0.5 g ST transiently increased the transmural electrical potential difference (PD). However, despite continued exposure, PD returned to baseline within 20 min. The mechanisms for these changes were explored by use of dog buccal mucosa mounted in Ussing chambers. Luminal exposure to a Ringer-extract of ST (EOST) increased PD and short-circuit current (Isc) and decreased electrical resistance (R), with changes reversible upon removal of EOST from the bath. Further, radioisotopic fluxes showed that the increase in Isc in EOST-exposed tissues was accompanied by increased absorption of electrolytes (Na, Cl, and other ions), and the decrease in R was accompanied by increased permeability to mannitol. Light microscopy of tissues exposed to EOST showed no morphological changes after exposure to 0.5 g of ST, but after exposure to 1.5-2.5 g of ST, dilated intercellular spaces were identified. Contact of aqueous media with ST led to the release of electrolytes and other soluble compounds into solution. To determine the effect of electrolyte release on buccal function, we exposed mucosae luminally to a solution with ion composition and/or osmolality similar to EOST or to one with an EOST previously dialyzed against Ringer. Solutions with similar ion composition and/or osmolarity changed PD, Isc, and R in a manner similar to EOST, while dialyzed-EOST had no effect. In addition, luminal nicotine produced effects different from EOST, decreasing PD and Isc and increasing R. These results indicate that ST can acutely alter buccal transport and barrier function by creating, through electrolyte release, electrochemical and osmolar gradients across the tissue.
Risk Factors for Dental Fluorosis in a Fluoridated Community
Authors: Osujp O.O. , Leake J.L. , Chipman M.L. , Nikiforuk G. , Locker D. , Levine N. 
Published: November 2010

We conducted a case-control study to determine the sources of fluoride which are particular risk factors to dental fluorosis. Cases and non-cases were identified by the screening of 8-, 9-, and 10-year-old schoolchildren in the fluoridated community of East York, Ontario-Parents were interviewed about the child's first five years of residence and about diet and preventive caries practices. The Mantel-Haenszel odds ratio and associated chi-square tests were used to assess the association of fluorosis with several potential sources, controlling for other sources of fluoride and mother's education. The prevalence of mild fluorosis [1-4 on the Thylstrup and Fejerskov (1978) Index] was 13%. Those who brushed their teeth before the age of 25 months had 11 times the odds of fluorosis compared with those beginning toothbrushing later; prolonged use of infant formula (≥ 13 months) was associated with 3.5 times the risk of fluorosis, compared with no, or shorter duration of, formula use. We estimate that these factors were responsible for 72% and 22%, respectively, of the cases in our population. Dental fluorosis is not a public health problem in East York, but parents should be advised to supervise toothbrushing by children under 2 years of age.
Arterial Blood Pressure Regulation of Pulpal Blood Flow as Determined by Laser Doppler
Authors: Sasano T. , Kuriwada S. , Sanjo D. 
Published: November 2010

Dynamic changes of pulpal blood flow (PBF) and gingival blood flow (GBF) induced by intra-venous injection of two kinds of vasoactive drugs were observed in dogs by means of Laser Doppler Velocimetry. Intra-venous injection of norepinephrine caused PBF to increase, corresponding to the blood pressure (BP) increase, while GBF decreased. Orciprenaline sulfate caused PBF to decrease parallel to the BP decrease, as compared with a GBF increase. The effects of these vasoactive drugs lasted longer on GBF than on PBF and BP. These results indicate that the regulation of blood flow in the dental pulp is more dependent on systemic blood pressure than on local vasoconstriction or vasodilation.
In vitro Caries-inhibitory Properties of a Silver Cermet
Authors: Swift E.J. 
Published: November 2010

Recurrent caries is one of the primary causes of failure of dental restorations. One method for reducing the frequency and severity of this problem is the use of fluoride-releasing restorative materials. The glass-ionomer cements are a type of fluoride-releasing material. They have been used extensively in recent years for a variety of clinical applications. However, in comparison with other restorative materials such as amalgam and composite resins, glass ionomers have relatively poor physical properties. Sintering of silver particles to glass-ionomer powder is a means of improving these physical properties. The sintered material is called a silver-glass ionomer or silver cermet. This study examined the in vitro caries-inhibitory potential of a silver cermet by means of two methods. First, long-term fluoride release was measured. Second, an artificial caries system was used for evaluation of caries inhibition by cermet restorations in extracted teeth. In comparison with a standard glass-ionomer restorative material, fluoride release from the cermet material was significantly less throughout a 12-month period. The results from the artificial caries system indicated that this decreased fluoride release corresponded with a lesser degree of caries inhibition. Lesions around cermet restorations in both enamel and root surfaces were significantly more severe than those around conventional glass-ionomer restorations. However, in compartson with amalgam and composite resin restorations, the cermet did have some cariostatic activity.