Calibration of equipment for analysis of drinking water fluoride: a comparison study.

Current American Dental Association evidence-based recommendations for prescription of dietary fluoride supplements are based in part on the fluoride concentration of a pediatric patient's drinking water. With these recommendations in mind, this study compared the relative accuracy of fluoride concentration analysis when a common apparatus is calibrated with different combinations of standard values. Fluoride solutions in increments of 0.1 ppm, from a range of 0.1 to 1.0 ppm fluoride, as well as 2.0 and 4.0 ppm, were gravimetrically prepared and fluoride concentration measured in pentad, using a fluoride ion-specific electrode and millivolt meter. Fluoride concentrations of these solutions were recorded after calibration with the following 3 different combinations of standard fluoride solutions: 0.1 ppm and 0.5 ppm, 0.1 ppm and 1.0 ppm, 0.5 ppm and 1.0 ppm. Statistical analysis showed significant differences in the fluoride content of water samples obtained with different two-standard fluoride solutions. Among the two-standard fluoride solutions tested, using 0.5 ppm and 1.0 ppm as two-standard fluoride solutions provided the most accurate fluoride measurement of water samples containing fluoride in the range of 0.1 ppm to 4.0 ppm. This information should be valuable to dental clinics or laboratories in fluoride analysis of drinking water samples.

Hand-held water fluoride analysis: An accessible caries prevention tool for dental professionals.

This study sought to compare the relative accuracy of a commercially available hand-held water fluoride analysis unit with a standard laboratory bench-top fluoride-specific electrode/millivoltmeter apparatus, with the goal of identifying possible practical applications of the hand-held unit for preventive dentistry. The units analyzed identical gravimetrically prepared fluoride solutions ranging from 0.1 to 4.0 ppm. The average difference between the measurements from the hand-held unit and the nominal values of the fluoride solutions was 0.011 ppm (SD = 0.068), and the average difference between the hand-held unit's measurements and the bench-top unit's measurements was 0.030 ppm (SD = 0.115). T-test analysis demonstrated no statistical difference between measurements from the hand-held unit with either the nominal values of the fluoride solutions or the bench-top unit's measurements. Results indicate that the hand-held water fluoride analysis unit has an appropriate level of accuracy for the measurement of fluoride levels in drinking water samples by dental professionals.

Weekly monitoring of the water fluoride content in a fluoridated metropolitan city--results after 1 year.

It continues to be the goal of the United States Department of Health and Human Services to fluoridate community water supplies to prevent dental caries. In Houston, Texas, where community water is assumed to contain in the range of 0.7-1.2 ppm fluoride, water samples were taken from the same source on approximately a weekly basis over a period of 52 weeks. The purpose of this study was to determine the extent of fluctuation of water fluoride concentration in these samples. Water fluoride analysis with an ion-specific electrode and millivolt meter of the data set showed a range of 0.33 to 1.00 ppm fluoride, with a mean of 0.70 ppm and a standard deviation of 0.15. This wide range of fluoride concentrations may create a risk for fluorosis in pediatric patients who are prescribed dietary fluoride supplements.

Fluoride content of bottled water and its implications for the general dentist.

This study sought to measure the fluoride concentration of various commercial bottled waters and to identify clinical implications in dental patient education and treatment. For this study, 105 different samples of bottled water were collected over a 30-day period (from October 15, 2007 to November 15, 2007), divided into six categories, and analyzed for fluoride concentration by utilizing a fluoride ion-specific electrode. Based on the present study, distilled bottled waters have an average fluoride content of less than 0.01 ppm, while drinking/purified bottled waters all (except for one sample) had an average fluoride content of less than 0.03 ppm. Spring/artesian bottled water had an average fluoride content of 0.08 ppm, compared with 0.32 ppm for mineral water bottled waters, 0.16 ppm for flavor-added bottled waters, and 0.63 ppm for fluoride-added bottled water.

Effects of a stannous fluoride-impregnated dental floss on in vivo salivary fluoride levels.

PURPOSE: The aim of this in vivo pilot study was to determine the concentration of fluoride retained intra-orally in saliva after flossing with dental floss impregnated with stannous fluoride (SnF(2)). METHODS: Participants flossed their teeth ad libitum with 2 premeasured lengths of fluoridated dental floss. Expectorated saliva samples were collected in vials before flossing (PF), immediately postflossing(IPF), at 30 minutes (30), and 1 hour (60) after flossing for analysis with a fluoride-specific electrode and an Orion millivoltmeter. Postflossing samples were compared to the preflossing samples using ANOVA and Tukey's HSD. RESULTS: Differences between the PF and IPF group means were found to be statistically significant at p<0.01. No other significant differences were found between or among any of the groups. Salivary fluoride levels at 60 minutes (60) were similar to those prior to flossing (PF). CONCLUSIONS: It can be concluded that fluoride can be released from flossing with the tested SnF(2)-impregnated dental floss elevating salivary fluoride levels for at least 30 minutes. Use of this fluoride-containing dental floss offers an option for delivery of fluoride to individuals at risk for dental caries.

Spontaneous recovery from early glomerular inflammation is associated with resistance to anti-GBM glomerulonephritis: tolerance and autoimmune tissue injury.

Different susceptibility to anti-GBM glomerulonephritis (GN) among animal strains has been reported. Using our rat model for T cell-mediated anti-GBM GN, this study initiated an investigation on the mechanism related with GN susceptibility. Anti-GBM GN was induced either through immunization with the nephritogenic T cell epitope pCol(28-40) from Col4alpha3NC1 or through the transfer of specific T cells. WKY rats were highly susceptible to GN while immuno-compatible LEW rats were GN-resistant. GN-resistance in LEW rats was not associated to the immune response to pCol(28-40). First, both strains mounted a Th1 T cell response to pCol(28-40) with identical specificities; transfer of T cells from LEW to WKY rats induced glomerular injury. Second, co-transfer of antibody from WKY to LEW failed to induce GN. Time-course studies revealed that LEW rats did develop T cell-mediated inflammation in glomeruli at early stages similar to WKY rats, as evidenced by histopathology, proteinuria, CD4(+) T cell infiltration in glomeruli, and glomerular expression of inflammatory molecules. However, glomerular inflammation in LEW rats was transient followed by a full recovery. Thus, GN-resistance in LEW rats was due to its ability to contain early T cell-mediated autoimmune glomerular damage. Our model may reveal a potential tolerance mechanism after autoimmune tissue damage has been initiated.

Fluoride knowledge and prescription practices among dentists.

The purpose of this study was to assess dentists' knowledge about fluorides as well as their prescription practices. The study population consists of all general and pediatric dentists in Houston, and the sample consists of 360 general and forty-one pediatric dentists. Data were collected with a self-administered mail questionnaire, which consisted of thirteen open-ended and twenty-nine precoded items. After three mailings, the effective response rate was 46.4 percent. Respondents had been in practice on an average of 18.9 +/-6.6 years; the majority were male. More than 75 percent of respondents believed fluoride level in drinking water is an important determinant of fluoride supplement prescription, and 29 percent felt the same about a patient's weight. The correct ages at which to begin (six months) and to discontinue (sixteen years) the fluoride supplements to children were identified by 14.7 and 14.9 percent of the respondents, respectively. Only 6.7 percent of those prescribing fluoride supplements routinely tested the fluoride level in the patient's drinking water. Even though pediatric and general dentists differed in certain items, the two groups did not differ significantly in prescribing fluorides (OR=2.4, 95% CI=0.94, 6.27). Deficiencies and ambiguity in respondents' fluorides knowledge as well as prescription practices indicated a need for educational interventions.

Tensile bond strengths of five luting agents to two CAD-CAM restorative materials and enamel.

STATEMENT OF PROBLEM: CAD-CAM restorative materials are popular because they have high esthetic value and short fabrication time. Unfortunately these materials are brittle and tend to fracture under heavy occlusal load. PURPOSE: The purpose of this in vitro study was to investigate the tensile bond strengths of 5 luting agents to 2 CAD-CAM restorative materials and enamel. Material and methods One hundred truncated cones, with a 3-mm diameter bonding surface and 5-mm diameter base, were fabricated with Dicor MGC (n=50) or Cerec Vitablocs Mark II (n=50) with the Cerec system. Enamel surfaces of the crowns of 100 freshly extracted noncarious, anterior teeth, stored in 0.9% saline solution with 0.25% sodium azide (NaN(3)) as disinfectant, were prepared with sandpaper disks (320-grit size) on the Buehler Variable Speed Grinder-Polisher. The bonding surfaces of the Dicor MGC or Cerec Vitablocs Mark II truncated cones from each of the 2 tests systems were airborne particle abraded, chemically etched, and cemented on the prepared enamel surface of the tooth specimens with 5 luting agents: Vita Cerec Duo Cement, EnForce, Panavia 21, C&B Metabond, and Fuji Duet. All specimens were thermocycled 1000 times, in 5 degrees C and 55 degrees C water with a dwell time of 30 seconds in each temperature. Tensile force (MPa) was applied perpendicular to the bonding surfaces of the specimens with a universal testing machine until fracture. Fracture patterns were examined with a microscope at original magnification x10. The differences in the tensile bond strengths were analyzed with the Tukey-Kramer test (alpha=.05). RESULTS: The mean tensile bond strengths of Dicor MGC bonding to enamel with luting agents in descending order in MPa were EnForce (10.12 +/- 2.25), Panavia 21 (7.28 +/- 1.77), Cerec Duo (5.32 +/- 1.65), Fuji Duet (3.73 +/- 1.78), and C&B Metabond (3.11 +/- 1.11). EnForce had a significantly higher bond strength than C&B Metabond, Fuji Duet, Cerec Duo, and Panavia 21 (P=.05). The mean tensile bond strengths of Cerec Vitablocs Mark II bonding to enamel with luting agents in descending order in MPa were as follow: Fuji Duet (11.51 +/- 2.79), EnForce (9.44 +/- 2.03), C&B Metabond (8.98 +/- 3.29), Cerec Duo (8.66 +/- 4.71), and Panavia 21 (5.10 +/- 2.49). Within this group, there was no significant difference between Fuji Duet and EnForce, but the bond strength of Fuji Duet was significantly higher than that of C&B Metabond, Panavia 21, and Cerec Duo (P=.05). The mean tensile strength of all the luting agents bonded to Cerec Vitablocs Mark II and enamel (8.74 MPa) was higher than Dicor MGC and enamel (5.91 MPa). CONCLUSION: In this in vitro study; within the Dicor MGC group, the mean bond strength of Panavia 21 with enamel was significantly higher than C&B Metabond, Panavia 21, Cerec Duo, and Fuji Duet. Within the Cerec Vitablocs Mark II group, the mean bond strength of Fuji Duet was significantly higher than C&B Metabond, Panavia 21, and Cerec Duo but was not significantly higher than EnForce.