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At least 955 records · Page 53Linked to original sources
PubMed1995

Toothpaste technique. Studies on fluoride delivery and caries prevention.

The aim of the investigations was to evaluate the cariostatic effects of a modified toothpaste technique using fluoride (F) toothpaste. The modification consisted of an active mouthrinse with the toothpaste slurry and a sip of water for one minute after brushing. Toothpaste technique and salivary F concentration after toothbrushing were recorded in a caries active and a caries inactive group. The level of F in whole saliva, the concentration of F in plasma, the effect on demineralised enamel and dentine samples, and the accumulation of F in interdental plaque when using the modified toothpaste technique were studied. In a 3-year clinical trial, 4-year old children were trained in the toothpaste technique. The results showed that in the caries active group, the water rinsing was more thorough and more water was used compared to a caries inactive group. Rinsing with water and eating immediately after toothbrushing decreased the F level in whole saliva. Mouthrinsing with either a NaF solution or a slurry of toothpaste foam and water increased the F concentration in saliva compared to when a single or double water rinse was performed. The degree of F absorption in plasma, the accumulation of F in approximal plaque and the interdental clearance after toothbrushing were strongly related to the mode of water rinsing. The degree of demineralisation of enamel and dentine at approximal sites was also related to the mode of water rinsing. The clinical study showed that the cariostatic effect of the modified toothpaste technique resulted in 26% less approximal caries in the test group. It is concluded that a toothpaste technique where a slurry rinse was carried out after brushing increased the efficacy of F toothpaste.

Absorption↗
PubMed1994

Fluoride-induced early teeth wearing in Argentinian cattle.

The relationship between observed early teeth wearing in cattle and the existence of large areas where excess fluoride in underground water prevails in Argentina, but has never been studied. Average values of bone fluoride exceeding 5000 ppm and well water containing up to 10.5 ppm of this element were found in a farm (ETWF) where early teeth wearing is observed, while in a control farm (NETWF), those values were 1480 ppm and 3.0 ppm respectively. Urine samples from animals from the ETWF contained almost 4 times more fluoride than those from the latter. Forage in both farms contained about the same levels of fluoride (15 to 25 ppm). None of the farms was exposed to industrial, volcanic, or geothermal activity. Lactating and adult animals were transferred from one farm to the other. After 30 months, adult animals from the NETWF showed no damage in teeth, while adults from the ETWF continued a rapid teeth wearing. Young animals from the NETWF developed severely damaged permanent teeth, while young animals from the ETWF developed normal teeth. We concluded that the problem exists in the ETWF and being a standard farm, the condition could be extrapolated to other areas.

Animals↗
PubMedDate not supplied

Teaching parents at WIC clinics to examine their high caries-risk babies.

Seventy-seven parents/caretakers of children, averaging 24.4 months from four WIC clinics in King County, Washington, observed a five-minute video-tape. These parents/caretakers were then asked to examine their own children, using a mirror and a brochure with illustrations of the progression of disease. Following completion of a questionnaire, a trained dental student or dentist examined the child and completed the same questionnaire. Over 80 percent of parents/caretakers responded the same as dentists. Dentists identified disease in 35.1 percent of the sample. Kappa = 59, Z = 4.4, and p < .001. Results support the training of nondental personnel to screen early childhood caries.

Bottle Feeding↗
PubMedDate not supplied

Argon laser irradiation and acidulated phosphate fluoride treatment in caries-like lesion formation in enamel: an in vitro study.

The purpose of this in vitro study was to determine the combined effects of argon laser irradiation (ArI) and acidulated phosphate fluoride treatment (APF) on caries-like lesion formation in human enamel. Each specimen was divided into tooth quarters with each quarter assigned to one of four groups: 1) control; 2) ArI Only; 3) ArI before APF treatment; 4) APF treatment before ArI. After a fluoride-free prophylaxis, acid-resistant varnish was applied to the tooth quarters, leaving sound enamel windows exposed on buccal and lingual surfaces. Argon laser irradiation was at 2 watts for 10s (100J/cm2). APF treatment was with a 1.23% APF gel for 4 min. Lesions were created in sound enamel windows with an acidified gel. After lesion formation, sections were obtained and imbibed with water for polarized light study. Body of the lesion depths were determined and compared among the four groups. Lesion depths were: 195 +/- 23 microns for control; 129 +/- 17 microns for ArI only; 96 +/- 14 microns for ArI before APF; and 88 +/- 11 microns for APF before ArI. Significant differences (P < 0.05) were found between the control group and all treatment groups, and between the ArI only group and both combined APF and ArI groups. Significant difference (P > 0.05) was not found between the ArI before APF and the APF before ArI groups. Laser irradiation alone reduced lesion depth by 34% compared with control lesions. When ArI was combined with APF treatment, lesion depth decreased by more than 50% compared with control lesions, and by 26 to 32% when compared with lased-only lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidulated Phosphate Fluoride↗
PubMed1993

Dentin: microstructure and characterization.

Dentin consists of several identifiable structures: tubules with cell processes and fluid; highly mineralized peritubular dentin; and intertubular dentin consisting mainly of collagen and deposited apatite. The structural organization and microstructural variations reflect formative influences, such as tooth size and shape, and alterations caused by age, insult, and disease. However, details of structure-chemistry-property relationships for this anisotropic biologic composite are limited. Materials scientists are focusing on an array of new spectroscopic, analytical, and imaging techniques that are yielding improved understanding of structural variations and their dependence on specimen preparation, tooth type, location, storage conditions, and chemical and physical modifications. Such studies should lead to the major refinements in structure-properties models for dentin that are required for continued advances in dental composite resins and adhesives.

Biomechanical Phenomena↗
PubMed1993

Permeability of dentin to adhesive agents.

The permeability of dentin to adhesive agents is of crucial importance in obtaining good dentinal bonding. In those systems that remove the smear layer, the opportunity exists for resin to infiltrate both tubules and intertubular dentin. Resin penetration into tubules can effectively seal the tubules and can contribute to bond strength if the resin bonds to the tubule wall. Resin infiltration into intertubular dentin can only occur if the mineral phase of dentin is removed by acidic conditioners or chelators. This is more easily accomplished in fractured dentin than in smear layer-covered dentin because of the residual collagen debris that remains on the surface following acid etching of smear layers. The channels for resin infiltration are the perifibrillar spaces created around the collagen fibers of dentin following removal of apatite mineral by acids. The diffusion of adhesive resins through these narrow, tortuous, long channels in 1 to 2 minutes offers a number of challenges that require further research.

Acid Etching, Dental↗
PubMed1993

[Does the application of a fluoride lacquer modify the de- and remineralization of initial carious lesions in vitro?].

Bovine enamel specimens with artificial initial lesions were fluoridated with a fluoride lacquer (Duraphat) for 6 hours. Subsequently artificial plaque (Streptococcus mutans, FA1) was grown on the enamel blocks in an artificial mouth. During the experimental period (23 days) the specimens were continuously rinsed with synthetic saliva and with sucrose twice daily. Nonfluoridated specimens served as controls. At the end of the experiment microhardness was evaluated in three levels parallel to the enamel surface. In addition, the concentration of KOH-soluble and structurally bound fluoride was determined. In the fluoridated specimens microhardness increased in levels near the surface of the lesion, but decreased in the next two lower levels. However, in the nonfluoridated enamel specimens microhardness decreased in all three levels and was more pronounced compared to the fluoridated specimens. At the end of the experiment no KOH-soluble fluoride could be determined on the surfaces of the artificial lesion. In contrast, structurally bound fluoride was significantly increased in the fluoridated specimens. A single application of the fluoride lacquer on initial enamel lesions resulted in remineralization of the outer enamel layers even under persisting cariogenic conditions. However, lesion progression could not be inhibited totally.

Animals↗
PubMedDate not supplied

Treatment of fluorosed and white-spot human enamel with calcium sucrose phosphate in vitro.

A number of treatments have been devised to improve the appearance of fluorosed enamel. However, many of these have been empirically based, and the success of the various treatment regimens have not been quantitated. In this study, the relative whiteness of normal, mildly fluorosed, moderately fluorosed, and carious white-spot lesions on extracted teeth was quantitated by light reflectance using a Minolta Chroma Meter. The color was again determined following a number of treatment regimens to assess the potential use of various agents in treating the enamel lesions. Treatment of the enamel with a 35% hydrogen peroxide gel resulted in a significantly increased whitening, which was not reduced by subsequent treatment (P < 0.05). Removal of the enamel surface with a dental bur, followed by treatment with 5.25% sodium hypochlorite and placement in an artificial saliva was successful for returning white-spot lesions to a normal enamel color. Treatment of enamel with 5.25% sodium hypochlorite followed by calcium sucrose phosphate paste and placement in artificial saliva was most successful in returning both white-spot and fluorosed lesions to a normal color. SEM imaging of the calcium sucrose phosphate treated enamel suggests that this treatment filled the porous enamel, resulting in a normal light reflectance from the enamel.

Calcium Phosphates↗
PubMedDate not supplied

Effects of carbamide peroxide whitening agents on enamel surfaces and caries-like lesion formation: an SEM and polarized light microscopic in vitro study.

Whitening enamel with carbamide peroxide (CP) to remove cosmetically displeasing stains has become common-place in dental practice. This in vitro study evaluated CP treatment effects on enamel surface morphology and caries-like lesion susceptibility. Tooth quarters were prepared from 10 caries-free human molars following a fluoride-free prophylaxis. The tooth quarters were assigned to the following treatment groups: 1) Distobuccal-10 percent NW gel (Nite White, Discus Dental); 2) Distolingual-10 percent PL paste (Platinum, Colgate); 3) Mesiobuccal-16 percent NW gel; and 4) Mesiolingual-Control. Following the manufacturers' recommended treatment, each quarter was sectioned with one portion prepared for SEM and the other portion for caries-like lesion formation. Intact enamel surfaces were present with all treatments. Enamel prism markings with exaggerated prism peripheries and mild to moderate prism core loss were seen with both 10 percent NW and 16 percent NW gels, but was more prominent with 16 percent NW gel. Amorphous surface layers with occasional exposure of indistinct prism markings occurred with 10 percent PL paste. Body of lesion mean depths were 135 microns control, 159 microns 16 percent NW, 144 microns 10 percent NW, and 122 microns 10 percent PL. Lesion depths were significantly different (p < 0.05 DMR paired design) between 10 percent PL and 16 percent NW, and between control and 16 percent NW. Whitening enamel surfaces in vitro with 10 percent carbamide peroxide paste containing dicalcium phosphate dihydrate (Colgate-Platinum) produced an amorphous surface layer and reduced caries susceptibility when compared with 16 percent carbamide peroxide gel (Nite White).

Carbamide Peroxide↗
PubMed1996

Quantitative contribution of the collagen network in dentin hybridization.

PURPOSE: To determine the quantitative contribution of dentin hybridization to bonded assembly strength and demonstrate the micromorphology of the interface with and without collagen present. MATERIALS AND METHODS: Four groups of 10 molar teeth were finished to a 320 grit dentin smear layer. Two groups served as controls and two experimental groups were subjected to collagenase digestion of the collagen exposed by acid conditioning. All-Bond 2 and Amalgambond were used to bond Bisfil and Epic resin composite, respectively. Stored in water at 37 degrees C for 24 hours the assemblies were tested in a shear mode at a crosshead speed of 5 mm/minute. Means and standard deviations were subjected to analysis for statistical significance. Twenty four teeth in four groups were examined by scanning (SEM) and transmission electron microscopy (TEM) for the relationship between resin and conditioned dentin with and without the collagen network. RESULTS: All-Bond 2 and Amalgambond controls were 28.41 +/- 3.9 and 19.04 +/- 5.96 MPa, collagenase-treated groups scored 26.43 +/- 2.90 and 19.70 +/- 4.25 MPa respectively. No significant difference existed between the control and experimental groups. SEM showed an intertubular collagen network with patent tubules and a pronounced porous, irregular dentin topography following collagen digestion. A distinct hybrid zone and tubular penetration was observed but the collagenase-treated specimens showed only resin in the tubules and their lateral extensions. TEM confirmed the absence of a distinct hybrid zone in the collagenase groups with a tight, gap-free junction between the resin and the undemineralized dentin. An electron dense zone (< 50 nm) at the leading edge of conditioning was observed for All-Bond 2 and Amalgambond groups. It was concluded that the resin-reinforced or hybridized, collagenous network does not detract from, nor contribute any significant quantitative value per se to dentin bonding with the systems tested.

Acid Etching, Dental↗
PubMed1997

[Adverse effects of orthodontic treatment].

The authors reviewed the adverse effects. The main effects are: demineralisation; gingivitis hyperplastica, mucogingival and marginal attachment bone loss, long-term-effects; pulp damage and devitalisation of teeth; apical and marginal root resorption; temporomandibular dysfunction.

Gingival Hyperplasia↗
PubMed1997

Cariostatic effect of glass ionomer retained orthodontic appliances. An in vivo study.

The cariostatic effect of a fluoride releasing bonding agent was investigated and compared with a conventional composite based material in connection with bonding of orthodontic brackets in 22 homologous pairs of premolars. All subjects had malocclusions requiring orthodontic treatment with fixed appliances and extraction of at least two premolars. 6-13 weeks prior to extraction, orthodontic brackets were bonded to the labial surfaces of the extraction teeth with either a glass ionomer cement or a bis-GMA resin. Initially, the children were instructed in tooth brushing and the regular use of fluoride. After extraction, the bonded teeth were stained and evaluated in a stereo-microscope regarding the incidence and extension of initial enamel demineralisation. The zone of intact enamel adjacent to the bracket base and bonding material was measured in a stereo-microscope at four predetermined locations with the aid of an electronic ruler and scored according to four categories. The incidence of enamel demineralisation adjacent to glass ionomer bonded and composite bonded brackets was 68% and 77% respectively. In 12 pairs of premolars however, the demineralisation appeared to a lesser extent on the enamel around the brackets was generally wider when glass ionomer cement was used compared to the composite resin. These differences were statistically significant (p < 0.05) mesially and distally, but non-significant cervically and incisally. The results indicate that bonding with glass ionomer cement may have a local cariostatic effect in children requiring fixed orthodontic appliances.

Adolescent↗