Clinical Efficacy of Caries Infiltration (Icon) - A Randomized, Blinded and Controlled Pilot Study of Early Caries Progression Detection

Introduction: Dental caries remains one of the most prevalent diseases worldwide. It is a dynamic process that causes destruction of tooth structure by dissolving the enamel. While it is possible to restore the structure and function of the tooth by placing a filling, it is preferable to slow down or reverse the caries process at an early state. Proximal surfaces are hereby particularly susceptible to caries as the contact area between teeth is difficult to access. While non-invasive techniques such as remineralization (using topical fluoride) or biofilm control are options to manage early caries lesions, their effectiveness may be compromised due to poor patient compliance. Alternatives are micro-invasive strategies such as resin infiltration, whereby a highly viscous resin is infiltrated into the porous enamel of caries lesions to erect an internal barrier that blocks acid diffusion, thereby inhibiting caries lesion progression. Another important aspect in caries management is diagnostic, with visual-tactile examination and radiographs being standard of care. However, visual-tactile techniques are known to be unreliable due to subjectivity and fail to differentiate between varies stages of caries progression. Caries diagnostic is thus assisted by radiographic imaging, which however, also has a limited sensitivity and requires the use of x-rays. While alternatives for caries imaging have been developed (e.g. quantitative laser or light fluorescence (QLF) or electrical conductance measurements (ECM)) no gold standard could be established so far highlighting the need for new save and sensitive imaging techniques. Objective: To assess the clinical efficacy of resin infiltration (Icon, DMG, Germany) compared to fluoride varnish (Duraphat Fluoride Varnish, Colgate, USA) in the management of proximal early caries lesions over 24 months. In addition, the use of a SFE laser optical device for the assessment of caries lesions and their progression will be assessed in comparison to radiographic examination. Materials and Methods: 50 volunteers (age 6-13 years) with at least 1 proximal early caries lesion in primary molars will be enrolled and randomly assigned to the resin infiltration and control groups. In the resin infiltration group early caries lesions will be treated using Icon (DMG), whereas the lesions in the control group will be managed using Oral Hygiene Instructions (OHI) and topical fluoridation (Duraphat Fluoride Varnish, Colgate). Lesion depth will be assessed through radiographic evaluation as well as through a novel optical device based on scanning fiber endoscope (SFE) technology for early caries detection through laser light imaging. SFE laser optical device prototypes developed by the University of Washington's Human Photonics Lab (HPL) will be utilized. Such a device is already in human use for applications such as imaging and cancer screening. Clinical Significance: Resin infiltration of early caries lesions may be an effective therapeutic strategy in paediatric dentistry to reduce caries progression. Additionally, the SFE optical device may be suitable technology to visualize early caries lesions and their progression, which would offer a safe alternative to radiography for assessing and monitoring dental caries.