## 4 Discussion  
To avoid unnecessary treatment, a diagnostic aid should show a very low level of false positive. This study investigated the use of caries detector dyes with or without the use of a bonding agent to explore the efficacy of caries detector dyes, which in turn will help provide some insight in its clinical applications and significance, as it will aid in providing clinicians with an objective means of diagnosing caries and preserving healthy tooth structure when treating carious teeth. Some studies showed that not all dye-stainable dentin was infected when it was compared to the level of infection of unstained and stained dentin at the amelodentinal junction, after the completion of the cavity preparation [32]. Caries detection dyes are less expensive, available in the market and can be used effectively as a complementary examination at the dental chair. The reason for using a caries detector dye is to make a clear-cut differentiation between the tissue to be removed and the tissue to be kept, ensuring a conservative treatment, and to avoid the possible exposure of the pulp. These nonspecific dyes will stain food debris, enamel pellicle and any other organic matter trapped in substantial amounts in occlusal fissures and possibly demineralized enamel, so false positives are of significant concern [24]. According to [PERSON] none of the caries detector dyes available are caries-specific, and their routine use can lead to overtreatment and pulp exposure [24]. In the present study we also observed similar results in group I, where all three caries detector dyes also stained noncarious part of the tooth surfaces. These results are in accordance with previous studies where authors have stated that dyes that reveal disintegration do not prove to be specific for caries lesions but also stain healthy circumpulpal dentin and healthy dentin at the enamel-dentin junction, which have a lower natural mineral content and are relatively more porous [23; 24; 25]. [PERSON] et al. found that the use of a caries indicator dye with a polypropylene glycol solvent showed comparatively less penetration than the propylene glycol solvent alone [40]. Also, in the present study, we have applied a dentin bonding agent without applying any etchant, since the etchant can further make enamel more porous in primary teeth, hence the chances of the dye taking up will be increased [41]. Interestingly, we noted that caries detecting dyes were not stained and penetrated in the sound tooth surfaces where the  
Figure 6: Mean values of distilled water and 3.25% sodium hypochlorite staining removal amongst the three different groups (Snoop, Sable seek and Elements). dentine bonding agent was applied on visibly caries-free surfaces. This study is the first of its kind where the effectiveness of the dentine bonding agent was investigated to evaluate the staining ability of caries detector dyes after the application of a dentine bonding agent. Further studies are required with sectioning and scanning the tooth surface to detect the ability of the bonding agent penetration and the avoidance of tooth staining by the caries detector dyes. In their report, [PERSON] et al. found that sound and carious dentin surfaces exhibited less bond strength with the application of caries detection dyes [37]. The study conducted by [PERSON] et al. using different cleaning solutions like distilled water, 3% sodium hypochlorite and 3% hydrogen peroxide for removing the residues of caries detector dyes revealed that sodium hypochlorite was more effective compared to the other agents, and the results were similar to those of the current study [39]. A limitation of the present study Is that although in vitro studies provide a tight control over chemical and physical environments, they fail to replicate the conditions of living organisms which can impede the extrapolation of the results obtained. Hence, future studies should focus on an in vivo model that can provide more reliable results.