Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel demineralization: a systematic review and meta-analysis.

To analyse clinical studies investigating coating agents such as sealants and other bonding materials to prevent the initiation or inhibit the progress of white spot lesions (WSL) during orthodontic treatment with fixed appliances. Electronic databases (Pubmed, CENTRAL, EMBASE) were screened for studies. No language restrictions were applied. Study selection, data extraction and quality assessment were done in duplicate. Primary outcome included assessment of WSL with visual-tactile assessment and/or laser fluorescence measurements. Twenty-four studies with 1117 patients (age: 11-40 years) and 12,809 teeth were included. Overall, 34 different sealants or bonding materials were analysed. Fourteen studies analysed fluoride and 14 studies non-fluoride releasing materials. Meta-analysis for visual tactile assessment revealed that sealants significantly decreased the initiation of WSL compared to untreated control (RR [95%CI] = 0.70 [0.53; 0.93]; very low level of evidence). Materials releasing fluoride did not decrease initiation of WSL compared to those with no fluoride release (RR [95%CI] = 0.84 [0.70; 1.01]; very low level of evidence). For laser fluorescence measurements no meta-analysis could be performed. The use of sealants seems to be effective in preventing the initiation of post-orthodontic WSL. Furthermore, there is no evidence supporting that fluoride-releasing sealants or bonding materials are more effective than those without fluoride release. No gold standard prevention strategy to prevent WSL during treatment with fixed orthodontic appliances has been established yet. However, based on only a limited number of studies the use of sealants seems to be effective in preventing the initiation of post-orthodontic WSL

Turbulent deposition of aerosol nanoparticles on a wire screen

This paper presents experimental results of aerosol penetration through a wire screen for mobilityequivalent particle diameters between 2 and 10 nm, Reynolds numbers for the 2uid approaching the screen (Ret) between 300 and 6000, Peclet numbers (Pe) between 20 and 13 000, and wire diameters between 40 and 100 m. An empirical expression, D =(2:53 + 5:14 × 10−4 Ret)Pe(−0:65+2:58×10−5Ret), correlating the single 8ber e9ciency, D, with the Peclet and Reynolds numbers has been obtained. In the limit of very low Reynolds number (Stokes regime) the above expression reduces to D0 =2:53Pe−0:65, which is in good agreement with the widely accepted correlation for fan model 8lters, D0 =2:7Pe−2=3, of Cheng and Yeh.This work was partly supported by Comunidad AutPonoma de Madrid under grant 07M=0097=2000Peer reviewe

Micro-filled resin infiltration of fissure caries lesions in vitro.

OBJECTIVES The aim of this in vitro study was to evaluate three treatment modalities [infiltrant resin (IR), micro-filled infiltrant resin (MFIR), infiltrant-sealant-combination (ISC)] regarding both their abilities to penetrate lesions differing in ICDAS-codes and to fill fissures and cavities. MATERIALS AND METHODS Extracted human molars (n=90) showing fissure caries lesions with and without cavitations were etched with 15% hydrochloric acid (HCl) that was mixed with abrasives and a 15% HCl-solution (1:1). The etching gel was rubbed for 30s within the fissure and, if eligible, within the cavity using a brush. After this pretreatment an infiltrant (Icon; DMG; IR) or an infiltrant mixed with microfillers (MFIR) was applied. ISC included the application of an infiltrant followed by a fissure sealant (Helioseal; Ivoclar Vivadent) From each tooth slices showing a non-cavitated (based on ICDAS-2) or cavitated lesion part (based on ICDAS-3/5) were prepared. Lesion (LA) and penetration areas (PA) as well as the completeness of fissure and cavity filling were analyzed using dual staining and confocal laser scanning microscopy. RESULTS Percentage penetration (PP) was calculated as 100×PA/LA. PP [median (25th/75th)] did not differ significantly between IR [95 (86/100)%], MFIR [93 (62/100)%] or ISC [89 (67/97)%] (p>0.05; Kruskal-Wallis test). All three materials filled about 90% of the dimensions of fissures and cavities (p>0.05; Kruskal-Wallis test). CONCLUSION It can be concluded that MFIR seems to be suitable to fill fissures and cavities like a fissure sealant and that it penetrates fissure caries lesions similarly deep as the conventional infiltrant after an experimental etching regime. CLINICAL SIGNIFICANCE The MFIR seems to combine advantages of the fissure sealing and the caries infiltration procedure

Modified resin infiltration of non-, micro- and cavitated proximal caries lesions in vitro

OBJECTIVE Infiltrant resin (IR) is currently indicated for non-cavitated caries lesions. However, modifying the technique might expand its indication spectrum to micro-cavitated lesions. The present study aimed to evaluate the penetration/filling ability of a newly developed micro-filled infiltrant resin (MFIR) in non-, micro- and cavitated natural caries lesions. MATERIALS AND METHODS Proximal lesions in 120 extracted human teeth with ICDAS-2 (n = 30), 3 (n = 45) and 5 (n = 45) lesions were etched with 15% hydrochloric acid gel for 2 min and allocated to one of the following treatments; IR: lesions (ICDAS-2, 3 and 5; each n = 15) were treated with commercial infiltrant resin for 3 min. MFIR: experimental MFIR [55 wt% IR plus 45 wt% organic fillers] was applied to lesions (ICDAS-2, 3 and 5; each n = 15) for 3 min. IR + FC: IR was applied for 3 min, light-cured, and cavities (ICDAS-3 and 5; each n = 15) filled with flowable composite (FC). Percentage infiltration of the demineralized enamel (Inf.%) and percentage filling of the cavity (Fill.%) were analyzed using dual-fluorescence staining and confocal microscopy. RESULTS No significant differences in Inf.% (range of medians: 57%-100%) were observed between different treatments (p > 0.05; Kruskal-Wallis) within each ICDAS-code. Fill.% of cavities was significantly higher in groups MFIR (median in ICDAS-3/-5: 100%/100%) and IR + FC (100%/100%) than IR (25%/38%) (p < 0.05). CONCLUSION MFIR showed similar penetration into natural lesions as the commercial infiltrant, but better ability to fill cavitated areas. CLINICAL RELEVANCE MFIR and IR + FC might provide a new micro-invasive treatment for small cavitated proximal lesions

Industry sponsorship in trials on fluoride varnish or gels for caries prevention

OBJECTIVES Fluoride is effective for caries prevention, but trials on fluoride varnish or gels are often industry-sponsored. We assessed trial design and findings in sponsored and nonsponsored trials on fluoride varnish and fluoride gels for caries prevention. METHODS Data on trials included in the most recent Cochrane Reviews on fluoride varnish and fluoride gels were extracted. Sample sizes/age/dentition, year/country of publication, follow-up, test and control, risk of bias and spin (claims of a beneficial effect that were not supported by reported data) were assessed. Studies were categorized as certainly, possibly and not sponsored, and statistically compared. Inverse-generic meta-analysis and multivariable weighted least-squares meta-regression were used to assess impact of sponsorship status on effect estimates. RESULTS Based on 19 nonsponsored, 14 possibly sponsored and 11 certainly sponsored trials, sponsored studies were published significantly earlier, always had >1 test group, and had significantly lower risk of spin. Caries-preventive effects were higher in earlier trials, without indication for sponsorship bias in trials published until 1990 (there were no sponsored trials afterwards). If assessing the overall body of evidence and accounting for confounders, the caries-preventive effect was significantly associated with year of publication (β: -0.06, 95% CI: -0.10/-0.02), but not sponsorship status. CONCLUSIONS Industry-sponsorship bias had limited impact on the overall evidence