Discussion
caries lesions, dentine, caries arrest, caries, cavitated, arrest
ARRESTED, ADVERSE EVENTS, THIGH DISEASE, CARIES, ARREST
The study showed that combining SDF + NaF produced significantly higher arrest rates for all lesions and for moderate lesions. The superior effect of SDF + NaF was not observed in the advanced lesions that were cavitated at baseline and the difference between groups was not significant. Although more parents were satisfied with their children’s appearance in the SDF + NaF group, the difference was not statistically significant, and staining was present in both groups. No adverse events or systemic manifestations were reported in both groups and transient gum blanching was observed in few children in the SDF group. The findings of the study support the rejection of the null hypothesis indicating that there is a difference between the two fluoride regimens in ECC arrest.The limitations of this study include the follow-up of 6 months which can be extended to longer follow-up periods in future studies to confirm the present conclusions. Also, some lesions might have been misdiagnosed since no radiographic examination was used because of the field conditions. Nonetheless, the study has several strengths including the large number of lesions which produced precise estimates with narrow confidence intervals. The exception for this was the estimate of the odds ratio for the arrest of moderate lesions which was imprecise because of the low number of this type of lesions per child. This reflects the distribution of lesions with different levels of severity in the study population with greater representation of advanced than moderate lesions. Another strength is the use of multilevel analysis to accommodate the clustering of teeth within children. Also, the community setting where the study was conducted supports the generalizability of findings to those with the greatest need of minimally invasive dental care.The study findings have implication for the non-invasive management of ECC. For young children with lesions of different levels of severity, combing SDF and NaF may arrest more lesions while for patients with advanced lesions, using only SDF may be adequate. These finding are useful in low- and middle-income countries like Egypt where resources are limited and where material cost and availability may affect the decision to use minimally invasive dental care. However, cost effectiveness evaluation of both interventions is needed to inform recommendations. The study adds to the knowledge base by directly comparing the two fluoride regimens and providing evidence on their relative impact on lesions with different severities thus offering clinicians more options to manage ECC non-invasively.The study also guides policy makers in planning and implementing prevention programs to reduce the burden of ECC in underserved areas with high disease burden.The present findings show a stronger effect of SDF + NaF than SDF in arresting ECC lesions. Direct comparison with previous studies is difficult due to differences in the choice of agents, as studies combining SDF and NaF are scarce, as well as differences in frequencies of application and follow up periods. One study [The authors reported an arrest of 74.1% of lesions, similar to the 77.7% in our study. Another trial registered in the clinicaltrials.gov registry (#NCT03480516) has been conducted in Thailand on school children aged 6–7 years old with active dentin caries lesions in primary canines and molars. The study aimed to assess caries arrest after applying 38% SDF and 5% NaF varnish every 6 months, but no results have been published yet.The reason for adding NaF to SDF in the present study was to improve the caries arrest potential of SDF. Previous studies assessed the possibility of reducing SDF staining by adding potassium iodide (KI) with concomitant evaluation of caries arrest. One study reported that when KI was added to Riva Star SDF (Riva Star, SDI Inc., Australia), 82% of advanced caries lesions in the primary molars of 6–9-year-old children [The study findings showed a stronger effect of SDF + NaF than SDF alone in moderate lesions rather than a weaker effect on advanced lesions where the percentage of SDF + NaF arrested moderate lesions was the highest among all subgroups possibly because of the effect of NaF on enamel/ moderate lesions [Our findings are also consistent with studies showing the relative advantage of NaF varnish in remineralizing enamel (ICDAS code 3) lesions [The greater arrest effect of SDF on dentine than enamel caries was documented in previous studies [Parents’ satisfaction with the appearance of their children’s teeth was high although teeth were stained. This can be attributed to the rural setting where the study was conducted where cultural norms and limited availability of services might have affected their acceptance of staining. These findings are consistent with studies conducted in China were parental satisfaction ranged from 65.7 to 70.3% [Further studies are needed in a clinical setting with radiographic assessment of lesion progress among children of young age and those with special needs where the intervention may be useful. This would complement the findings of our study which targets children from disadvantaged backgrounds in field conditions. Also, Further research is needed to assess the effect of both regimens on caries increment and on reducing the number of new lesions affected by caries beyond the lesions on which the agents are applied, for longer periods as well as cost effectiveness of both interventions. This information would help guide the decision to combine SDF and NaF to prevent ECC depending on the stage of lesion progress.