School Based Tooth Brushing and Annual Silver Diammine Fluoride Application as a Highest Priority Package for Achieving Universal Oral Health Care for Cambodian Children

Background: Achieving Universal Oral Health Care among Low-to Middle-Income settings is challenging and little literature exists around exploring what a “Highest Priority Package” of care might look like in the context of oral health. The Healthy Kids Cambodia (HKC) program differs from most conventional school dental services in that the initial package of care that is offered is daily toothbrushing with 1,500 ppm fluoride toothpaste (DTB) together with the topical application of Silver Diamine fluoride (SDF) for management of lesions in primary teeth.

Aim: To examine tooth level outcomes for 8- to 10-year old children from two schools that performed DTB with application of SDF at differing time-points.

Design: This was an observational cohort study that examined lesion progression among children in late mixed dentition at two schools. Data were collected using the dmft and pufa indices. Both schools received materials and training for DTB at baseline. School One received SDF at baseline while School Two received SDF after 9-months. Intraoral examinations were performed and the presentation of primary teeth with cavitated carious lesions were compared at baseline and 12 m. If a tooth was still caries-active or had become pulpally involved, this was considered to be an unacceptable outcome. Descriptive analysis was performed the chi-squared test was used to examine differences in the proportion of teeth with unacceptable outcomes by school membership.

Results: Of the 521 children recruited, 470 (90.2%) were followed. Where there was a delay in SDF application (School 2) there was a three times greater chance of an unacceptable outcome. Ten percentage of primary teeth in School One and 33% of primary teeth in the School Two had unacceptable outcomes.

Conclusion: The present study offers data on expected effect sizes that might inform future step-wedged clinical trials to validate an oral health Highest Priority Package of care for Cambodian children. The delivery of a package of care that includes both DTB and SDF can prevent adverse outcomes, such as dental infections, in primary teeth with carious lesions.

The Manufacture and Characterization of Silver Diammine Fluoride and Silver Salt Crosslinked Nanocrystalline Cellulose Films as Novel Antibacterial Materials

There is an unmet need for biocompatible, anti-infective, and mechanically strong hydrogels. This study investigated the use of poly vinyl alcohol (PVA), polysaccharides, and nanocrystalline cellulose (CNC) to deliver silver in a controlled manner for possible use against oral or wound bacteria. Silver was included in solvent cast films as silver diammine fluoride (SDF) or as nitrate, sulphate, or acetate salts. Hydrogel formation was assessed by swelling determinations and silver release was measured using inductively coupled plasma methods. Antibacterial studies were performed using Gram-positive and negative bacteria turbidity assays. PVA formed homogenous, strong films with SDF and swelled gently (99% hydrolyzed) or vigorously with dissolution (88% hydrolyzed) and released silver slowly or quickly, respectively. CNC-SDF films swelled over a week and formed robust hydrogels whereas CNC alone (no silver) disintegrated after two days. SDF loaded CNC films released silver slowly over 9 days whereas films crosslinked with silver salts were less robust and swelled and released silver more quickly. All silver loaded films showed good antibacterial activity. CNC may be crosslinked with silver in the form of SDF (or any soluble silver salt) to form a robust hydrogel suitable for dental use such as for exposed periodontal debridement areas.

Shear bond strength and interfacial analysis of high-viscosity glass ionomer cement bonded to dentin with protocols including silver diammine fluoride

PURPOSE

High-viscosity glass ionomer cements (HV-GICs) are reinforced with ultrafine, highly reactive glass particles, as well as a higher-molecular-weight polyalkenoic acid component. Silver diammine fluoride (SDF) is an agent with promising activity against active caries. The present study aimed to evaluate the shear bond strength (SBS) and interfacial morphology of a new HV-GIC bonded to dentin after treatment with various adhesive protocols including SDF.

METHODS

HV-GIC cylinders were bonded to dentin after various surface treatments (6 groups, n = 22): water; polyalkenoic acid; SDF; SDF + potassium iodide (KI); SDF + KI + polyalkenoic acid; SDF + KI + two weeks of storage in water + polyalkenoic acid. For each group, 20 samples were tested for SBS after 48 h, and 2 samples were cut and subjected to environmental scanning electron microscopy (E-SEM) and energy-dispersive X-ray (EDX) analysis.

RESULTS

No significant differences in SBS were found between any of the protocols tested. However, E-SEM and EDX images showed different interfaces when SDF was applied.

CONCLUSION

SDF has no influence on the adhesion of HV-GIC to sound dentin and could potentially improve the cario-resistance of the dentin/HV-GIC interface.

Parental acceptance of silver diammine fluoride in children with autism spectrum disorder

BACKGROUND

Parents of children with autism spectrum disorder (ASD) may have concerns with fluoride/silver content in silver diammine fluoride (SDF).

AIM

To compare parental acceptance of SDF and dental fear between children with and without ASD.

DESIGN

Three hundred parents were enrolled. Demographics, dental history, and dental fear were recorded. Subjects viewed an educational video and completed survey about SDF acceptance including the following: (a) overall acceptance, (b) aesthetic concerns by tooth location, (c) fluoride/silver concerns, and (d) its use as a general anaesthesia (GA) alternative. Descriptive, bivariate, and multivariate analyses were used.

RESULTS

Significantly, more children with ASD had dental fear (ASD: 56% vs neurotypical: 26%). No differences in acceptance existed between the two groups overall or with respect to aesthetics, fluoride/silver content, or as an alternative to GA. Overall acceptance is >60%. Regardless of group, parents of older children were less likely to accept SDF as an alternative to GA (OR = 0.67 [95% CI: 0.50-0.90]).

CONCLUSION

Parents of children with ASD had similar acceptance of SDF use compared to parents of neurotypical children. Children with ASD had higher levels of dental fear. Parents of younger children are more likely to accept SDF as an alternative to GA in both groups.

Does previous application of silver diammine fluoride influence the bond strength of glass ionomer cement and adhesive systems to dentin? Systematic review and meta-analysis

BACKGROUND

Silver diammine fluoride (SDF) applied before a restoration may prevent recurrent caries; therefore, its effect on the bonding of restorative materials is contradictory.

AIM

To assess through a systematic review and meta-analysis the influence of SDF on the bonding performance of adhesive materials to dentine.

DESIGN

A systematic search was carried out in PubMed, Web of Science, LILACS, and Scopus. Studies comparing bond strength of adhesive systems or glass ionomer cement to SDF-treated and -untreated (control) dentine were included. Global analysis comparing the bond strength data was performed, separately for adhesive systems and glass ionomer cement, using RevMan5.1, with a random-effect model, at a 5% significance level.

RESULTS

Eleven studies were included in the review and ten in the meta-analyses. Overall pooled effect for glass ionomer cement has shown no significant difference between the groups (Z = 0.47; P = .64). SDF treatment significantly impairs the bonding of adhesive systems to dentine (Z = 2.11; P = .03); this effect can be eliminated by the rinsing step (Z = 0.85; P = .40).

CONCLUSIONS

The previous application of SDF does not influence the dentine bond strength of glass ionomer cement, but compromises the bonding of adhesive systems.

Microcomputed Tomography Evaluation of Root Dentin Caries Prevention by Topical Fluorides and Potassium Iodide

The mineral content of dental hard tissues has traditionally been measured by destructive tests such as transverse microradiography. Microfocus X-ray computed tomography (micro CT) has enabled non-destructive 3D assessment of tooth demineralization. This study compared the preventive effects of silver diammine fluoride (SDF) and potassium iodide (KI) in comparison with fluoride varnish. SDF has been known to arrest caries but darkens the tooth. KI creates a precipitate with SDF that reduces the discoloration, but its effects on SDF efficacy in terms of preventing demineralization of at-risk root dentin surfaces is unknown. Bovine root dentin blocks were randomly distributed into four groups and subjected to a pretreatment in each group (n = 8); Control: deionized water (DIW); F-Varnish: 5% sodium fluoride varnish: 38% Saforide; SDF+KI: SDF followed by saturated solution of KI in DIW. The treated dentin was subjected to 8 cycles of demineralization (pH 5) for 14 h and remineralization in artificial saliva (pH 7) for 10 h. Specimens were then scanned for 12 min using micro CT at 73 KV and 1012 µA with 8.3 μm resolution. The 3D images were analyzed in Amira software to calculate lesion depth (LD), surface layer mineral density (SL) and mineral loss (ΔZ) for each specimen. One-way ANOVA with Bonferroni posthoc showed that there was a statistically significant difference between Control and all three other groups for all parameters (P < 0.001), however, there was no statistical difference among F-Varnish, SDF and SDF+KI (P > 0.05). Single application of F-Varnish, SDF and SDF+KI showed comparable preventive effects against root dentin demineralization. Application of KI did not affect anti-demineralization properties of SDF in this study. Micro CT is a quick and effective method for objective and high-resolution characterization of dentin caries lesions.

In vivo antimicrobial activity of silver diammine fluoride on carious lesions in dentin

Minimally invasive treatment protocols may leave a residual layer of carious dentin, which requires treatment for the inhibition of bacterial growth beneath restorations. We aimed to examine the in vivo effect of silver diammine fluoride (SDF) and SDF + potassium iodide (KI) application on bacteria present in deep carious lesions. We studied the in vivo efficacy in five patients, each of which had five carious lesions. Dentin samples taken before and after treatment were subjected to microbial analyses. Following treatment with SDF, the median colony-forming unit (CFU) counts per mg of dentin reduced from 9 × 10⁵ to 1.6 × 10² (P < 0.05), and following that with SDF + KI, the counts decreased from 2.9 × 10⁵ to 9.2 × 10 (P < 0.05). The use of chlorhexidine gluconate (CHX) reduced CFU counts from 1.1 × 10⁵ to 4.8 × 10² (P < 0.05). In four of the five patients, no CFUs were found on mitis salivarius-bacitracin agar with respect to SDF or SDF + KI application. For CHX, the median CFU count before treatment was 1.6 × 10³ and that after treatment was 1.1 × 10². SDF completely inhibited mutans streptococci growth in four of the five patients, while the growth of anaerobes was not completely inhibited.

Silver deposition on demineralized dentine surface dosed by silver diammine fluoride with different saliva

AIM

Silver diammine fluoride (SDF) is an anticaries agent that binds to tooth tissue. The aim of the present study was investigate the dose-response effect of SDF on demineralized dentine in basal medium mucin (BMM) saliva substitute and human saliva.

METHODS

Dentine discs stored in saliva substitute, BMM, and human unstimulated whole saliva (UWS) were chemically demineralized, and 10 μL of 10 wt%, 24 wt%, or 38 wt% SDF was applied and then stored in its respective saliva (BMM or UWS) for 5 days. Dentine disc samples were digested in 70% HNO₃ , and silver was quantitatively detected by inductively coupled plasma mass spectroscopy.

RESULTS

For both the BMM and UWS groups, the presence of silver increased proportionally with increasing concentrations of SDF (P < 0.05). For the 38 wt% SDF application, the mean absorption percentage of silver in dentine was 3.90% for the UWS group and 6.61% for the BMM group. The BMM group was found to yield a significantly higher amount of silver compared to UWS at 10 wt% and 38 wt% SDF application (α = 0.05); 38 wt% SDF interacts more with BMM with higher silver deposition than UWS.

CONCLUSION

The amount of silver found in dentine was in proportion to the concentration of SDF. Extrapolation of in vitro investigations using artificial saliva for SDF tooth interactions should be interpreted with caution.

Effect of Glutathione Bio-Molecule on Tooth Discoloration Associated with Silver Diammine Fluoride

This study evaluated the effect of Glutathione (GSH) bio-molecule on the reduction of enamel and dentin discoloration after application of 38% silver diammine fluoride solution (SDF). One hundred and twenty bovine teeth specimens were used. The enamel and dentin specimens were divided into three groups: (1) SDF only (control); (2) SDF followed by application of a potassium iodide solution (KI); and (3) SDF mixed with 20% GSH. Half the specimens were exposed to light and the remainder kept in dark conditions (n = 10) Color changes were measured using a spectrophotometer at the following time intervals: before solution application (baseline) and immediately after application, then 3, 6, 24, 48, 72 h, and 7, 10 and 14 days. SEM/EDS analysis was performed on treated enamel and dentin. Statistical analysis was done using a repeated measures ANOVA test. The spectrophotometer results showed that the SDF group exhibited the greatest color changes under both light exposed and dark conditions, while SDF + GSH group was effective in decreasing the color changes in both light and dark conditions. The SDF + KI group showed an insignificant color changes over time. SEM/EDS analysis showed different patterns for the silver crystal formation in each group (SDF, SDF + GSH, and SDF + KI group). It was concluded GSH can effectively minimize color changes after application of SDF, especially on enamel and to a lesser extent on dentin.