Dental caries is a prevalent oral disease among elders worldwide. Epidemiological studies have shown that the incidence of root caries increases with age, and the prevalence of root caries in elders is high ⁽¹⁾. In recent surveys in many countries, around half of community-dwelling elders had root caries experience ⁽²⁾. For elders living in long-term care facilities, the oral health situation is usually poorer, with very high levels of untreated dental caries ⁽³⁾. There is an urgent need to prevent root caries among elders, especially those who are institutionalized. Clinical studies on dental caries prevention have so far been focused on coronal caries in children and adolescents. Little is known regarding the effectiveness of various caries-preventive agents on root surface caries. The reported prevalence of dental caries in elders varies in different countries but a high proportion of the caries lesions being untreated active decay is common ⁽⁴⁾. Poor oral health knowledge, infrequent tooth brushing, and low utilization of dental care services among the elders are some possible explanations for the high proportion of untreated dental caries ^{(4, 5)}.

Since advanced dental caries can cause pain, tooth loss, and impact on general health, there is a need to develop affordable and effective treatment approaches to manage the untreated root caries lesions on tooth surfaces in elderly people. Nonsurgical intervention for shallow dentin caries lesions has been advocated. The topical application of fluoride agents is conservative treatment and a potentially good alternative to the surgical approach. Fluorides have been proved to be the single most effective weapon in the still limited arsenal of anti-caries agents in the last 60 years. Studies also conclude that caries preventive effects of fluoride are almost exclusively topical. 

Silver diamine fluoride (SDF), Ag(NH3)2F, has been used to arrest caries since 1969. Silver diamine fluoride is effective in arresting dentin caries in primary teeth of young children and is recommended for preventing and arresting dental caries lesions ⁽⁶⁾.

The caries arrest activity of silver fluoride solutions occurs through a number of mechanisms including the fluoride enhancing mineral formation, hardening of the tooth surface, and the inhibition of the enzymes that break down tooth structure (matrix metalloproteinase inhibition). The silver and fluoride are normally carried in an alkaline solution and there are a number of different carriers that have been used. The main disadvantage of treatment with Silver Fluoride solution is that the cavitated carious lesions become a darker color. This can result in poor aesthetics that could potentially be stigmatizing or unacceptable to children and their families. For that reason, it is important to explore ways in which clinicians can achieve the most aesthetically favorable outcome ⁽⁷⁾. In 2005, G.M. knight introduced a new approach to overcome the problem of SDF staining by applying a saturated solution of potassium iodide (KI) immediately after SDF application to reduce the staining of silver particles ⁽⁸⁾.

Based on this, the present study is designed to evaluate patient’s satisfaction level, and Streptococcus mutans colony count following a single application of SDF with and without KI among community-dwelling geriatric population in Chennai city.