Daily Archives: November 8, 2012

Fluoride self-care administration is possible

Zero DT; Marinho VC; Phantumvanit P. Effective use of self-care fluoride administration in Asia. Advances In Dental Research 2012 Feb; Vol. 24 (1), pp. 16-21.

The caries-preventive benefits of fluoride are generally accepted by dental researchers and practicing professionals worldwide. The benefits of fluoride toothpastes and mouthrinses have been supported by several high-quality systematic reviews. The formulation of a fluoride toothpaste and biological (salivary flow rate) and behavioral factors (brushing frequency, brushing time, post-brushing rinsing practices, timing of brushing, and amount of toothpaste applied) can influence anticaries efficacy. Fluoride mouthrinses have simpler formulations and can have better oral fluoride retention profiles than fluoride toothpastes, depending on post-brushing rinsing behaviors. Fluoride continues to be the mainstay of caries control; however, there is still the need to determine the most effective approach for fluoride utilization in children and adults who remain caries-active.

A novel fluoride delivery system…

Baturina O; Tufekci E; Guney-Altay O; Khan SM; Wnek GE; Lindauer SJ.  Development of a sustained fluoride delivery system. The Angle Orthodontist  2010 Nov; Vol. 80 (6), pp. 1129-35.

Objective: To develop a novel delivery system by which fluoride incorporated into elastomeric rings, such as those used to ligate orthodontic wires, will be released in a controlled and constant manner.

Materials and Methods: Polyethylene co-vinyl acetate (PEVA) was used as the model elastomer. Samples (N = 3) were prepared by incorporating 0.02 to 0.4 g of sodium fluoride (NaF) into previously prepared PEVA solution. Another group of samples prepared in the same manner were additionally dip-coated in PEVA to create an overcoat. Fluoride release studies were conducted in vitro using an ion selective electrode over a period of 45 days. The amount of fluoride released was compared to the optimal therapeutic dose of 0.7 microg F(-)/ring/d.

Results: Only coated samples with the highest fluoride content (group D, 0.4 g of NaF) were able to release fluoride at therapeutic levels. When fluoride release from coated and uncoated samples with the same amount of NaF were compared, it was shown that the dip-coating technique resulted in a fluoride release in a controlled manner while eliminating the initial burst effect.

Conclusions: This novel fluoride delivery matrix provided fluoride release at a therapeutically effective rate and profile.

Alternatives to communal water fluoridation

Tubert-Jeannin S; Auclair C; Amsallem E; Tramini P; Gerbaud L; Ruffieux C; Schulte AG; Koch MJ; Rège-Walther M; Ismail A. Fluoride supplements (tablets, drops, lozenges or chewing gums) for preventing dental caries in children. Cochrane Database Of Systematic Reviews (Online) 2011 Dec 07 (12). Cochrane AN: CD007592.

Background: Dietary fluoride supplements were first introduced to provide systemic fluoride in areas where water fluoridation is not available. Since 1990, the use of fluoride supplements in caries prevention has been re-evaluated in several countries.

Objectives: To evaluate the efficacy of fluoride supplements for preventing dental caries in children.

Search Methods: We searched the Cochrane Oral Health Group’s Trials Register (to 12 October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3), MEDLINE via OVID (1950 to 12 October 2011), EMBASE via OVID (1980 to 12 October 2011), WHOLIS/PAHO/MEDCARIB/LILACS/BBO via BIREME (1982 to 12 October 2011), and Current Controlled Trials (to 12 October 2011). We handsearched reference lists of articles and contacted selected authors.

Selection Criteria: We included randomised or quasi-randomised controlled trials comparing, with minimum follow-up of 2 years, fluoride supplements (tablets, drops, lozenges) with no fluoride supplement or with other preventive measures such as topical fluorides in children less than 16 years of age at the start. The main outcome was caries increment measured by the change in decayed, missing and filled tooth surfaces (DMFS).

Data Collection and Analysis: Two review authors, independently and in duplicate, assessed the eligibility of studies for inclusion, and carried out risk of bias assessment and data extraction. In the event of disagreement, we sought consensus and consulted a third review author. We contacted trial authors for missing information. We used the prevented fraction (PF) as a metric for evaluating the efficacy of the intervention. The PF is defined as the mean caries increment in controls minus mean caries increment in the treated group divided by mean caries increment in controls. We conducted random-effects meta-analyses when data could be pooled. We assessed heterogeneity in the results of the studies by examining forest plots and by using formal tests for homogeneity. We recorded adverse effects (fluorosis) when the studies provided relevant data.

Main Results: We included 11 studies in the review involving 7196 children. In permanent teeth, when fluoride supplements were compared with no fluoride supplement (three studies), the use of fluoride supplements was associated with a 24% (95% confidence interval (CI) 16 to 33%) reduction in decayed, missing and filled surfaces (D(M)FS). The effect of fluoride supplements was unclear on deciduous or primary teeth. In one study, no caries-inhibiting effect was observed on deciduous teeth while in another study, the use of fluoride supplements was associated with a substantial reduction in caries increment. When fluoride supplements were compared with topical fluorides or with other preventive measures, there was no differential effect on permanent or deciduous teeth.The review found limited information on the adverse effects associated with the use of fluoride supplements.

Authors’ Conclusions: This review suggests that the use of fluoride supplements is associated with a reduction in caries increment when compared with no fluoride supplement in permanent teeth. The effect of fluoride supplements was unclear on deciduous teeth. When compared with the administration of topical fluorides, no differential effect was observed. We rated 10 trials as being at unclear risk of bias and one at high risk of bias, and therefore the trials provide weak evidence about the efficacy of fluoride supplements.

No changes in El Nino frequency from global warming

S. Ray, B.S. Giese. Historical changes in El Niño and La Niña characteristics in an ocean reanalysis. Journal of Geophysical Research, Vol. 117, C11007, 2012. doi:10.1029/2012JC008031

The variation of El Niño Southern Oscillation (ENSO) events from the mid-nineteenth century until the beginning of the twenty-first century is explored using an ocean reanalysis. A comparison of the reanalysis with three sea surface temperature reconstructions shows that the timing of events is similar in all four products, however there are important differences in the strength and location of events. The difference between the reconstructions is sometimes larger than the difference between the reanalysis and a given reconstruction. These differences are larger in the first half of the record, a period for which there are relatively sparse observations. The reanalysis is used to explore decadal variability and trends in the frequency, duration, and propagation direction of ENSO events. There is considerable decadal variability of these ENSO characteristics with the time between events ranging from several months to ten years and the duration of ENSO varying from 5 to 27 months. As has been previously shown for the strength and location of ENSO there is little overall trend in the characteristics. Having a three dimensional representation of the ocean from the reanalysis allows exploration of subsurface changes during ENSO. An analysis of subsurface anomalies shows that during ENSO events the subsurface anomalies are highly correlated with the strength of surface anomalies over the 140 year period. Overall, there is no evidence that there are changes in the strength, frequency, duration, location or direction of propagation of El Niño and La Niña anomalies caused by global warming during the period from 1871 to 2008.

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