Evaluation of the effect of 38% silver diamine fluoride (SDF) on dentinal caries lesion in primary teeth with & without light cure application-an in vivo scanning electro microscopic (SEM) study

Dental caries is defined as a chronic, stereotypically widespread illness which affects child population to variable degree of severity. It is a complex process showing progression involving dietary sugars, bacterial metabolism, demineralization and organic degradation. The collagenous organic matrix is exposed once a dentin surface is demineralized and destroyed by bacterial proteases. Dentinal caries is the situation in which caries has progressed into dentine and caused significant loss of structure and lesion depth. Traditional management of dentinal caries has focused primarily on treatment via excision of diseased tissue and subsequent restoration of defect, but it is destructive and irreversible procedure in which healthy dental tissue may get destroyed. The contemporary caries management philosophy has new advancements which changed from traditional approach to medical model, often includes more conservative procedures like fluoride therapy. Among the fluorides agents, silver diamine fluoride [SDF] is drawing much attention from both researchers and dental clinicians since it has unique ability to halt caries process and simultaneously prevent new caries, makes it different from other agents. Meta-analysis have found 81% success rate of SDF in a study in 2016. It is an inexpensive mode of treatment which is minimally invasive and available for off label use in paediatric dental clinics, been rapidly adopted by clinicians.  It is indicated in high caries risk, treatment challenges with high behaviour and medical management, multiples caries which cannot be treated in single visit, lesions which are difficult to treat and patient without access to proper dental care.  SDF is composed of diamine silver ion and fluoride ion, in which diamine silver ion form complex structures by attaching to ammonia molecules. Silver act as an antimicrobial, fluoride provides remineralization and ammonia stabilises high concentrations in solutions . Upon application on decayed surface, squamous layer of silver conjugate forms on exposed dentin, partially plugging the exposed dentin and increasing resistant to acid dissolution and enzymatic digestion.  it acts on proteins which breakdown the exposed dentine organic matrix: matrix metalloproteinases, cathespins, and bacterial collagenases, acting directly against lesion by breaking membranes, denaturing proteins and inhibiting DNA replication. It outperforms other anti caries medicament in killing cariogenic bacteria in dentinal tubules. there are some studies which shows that dental curing light increase silver ion penetration and improve action of SDF. Also it increases hardness of infected dentin, causing less penetration of SDF on sound dentin which is beneficial in halting deep dentinal caries approaching pulp.There have been many in vitro studies regarding action of SDF but still there are not many evidences regarding its ultramicroscopic action on dentinal caries and effect of light cure action. In vivo evidences on mode of action of SDF in arresting dental caries is still lacking. Also there are always efforts going on to improve clinical efficacy of 38 % SDF, Therefore present study is planned to study the action of 38% SDF at clinical and microscopic level with high resolution of imaging and low artefacts with both with and without action of visible light cure application.