Clinical Trial Proximal Caries Infiltration and Detection

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

The purpose of this study is to investigate 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 in primary molars over 24 months. In addition, this study will assess the use of a scanning fiber endoscope (SFE) laser optical device for the assessment of caries lesions and their progression in comparison to radiographic examination. A total of 50 participants (age 6-13 years) with at least 1 proximal early caries lesion will be enrolled. The participants will be followed up at 12 and 24 months. Lesion status will be monitored through radiographic and SFE laser optical device imaging.

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.

Enrolled proximal early caries lesions will be treated using the resin infiltrant Icon (DMG, Germany).

Oral hygiene instruction and topical fluoridation therapy (Duraphat Fluoride Varnish, Colgate, USA) will be provided.

Up to two proximal early caries lesions (only if the second lesion is in a separate quadrant) per participant will be included. After radiographic and SFE imaging to assess lesion depth, the study lesions will be treated using the resin infiltrant Icon (DMG, Germany) according to manufactures´ instructions. Essentially, the treatment consists of the following parts: 1) isolating the tooth with a rubber dam and cleaning its surface; 2) removing/ conditioning the surface layer of the lesion (using Icon-Etch) to open the lesion body; 3) drying of the exposed porous enamel; 4) infiltrating the existing pore volume with the resin infiltrant (Icon Infiltrant); 5) light curing of the resin infiltrant; 6) repeating the infiltration step including light curing; followed by 7) finalizing using interproximal finishing/polishing strips.

Up to two proximal early caries lesions (only if the second lesion is in a separate quadrant) per participant will be included. After radiographic and SFE imaging to assess lesion depth oral hygiene instruction and topical fluoridation therapy will be provided. For topical fluoridation Duraphat Fluoride Varnish (Colgate, USA) will be used according to manufactures´ instructions.

Change in categorical lesion depth (progression to next depth category lesion; E1->E2->D1->D2->filling) as measured by pairwise comparison of radiographs (baseline versus follow up time point). E1 (lesion within the outer half of enamel), E2 (inner half of enamel), D1 (outer third of dentin), D2 (middle third of dentin).

Categorical lesion depth (E1, E2, D1, D2) is measured using SFE imaging. The results are compared to the assessment of categorical lesion depth using radiographic imaging (state of the art method). Outcomes are defined as follows: 1) positive (if SFE imaging gave the same result as the radiograph analysis), 2) negative (if SFE imaging gave a different result as the radiograph analysis) and 3) failure (if lesion depth could not be assessed using SFE imaging). Categorical lesion depth: E1 (lesion within the outer half of enamel), E2 (inner half of enamel), D1 (outer third of dentin), D2 (middle third of dentin).

Change in categorical lesion depth (progression to next depth category lesion; E1->E2->D1->D2->filling) as measured by pairwise comparison of radiographs (baseline versus follow up time point). E1 (lesion within the outer half of enamel), E2 (inner half of enamel), D1 (outer third of dentin), D2 (middle third of dentin).

Inclusion Criteria: Age 6-13 years Early caries lesions in primary molars (depth: E1 or E2) Good general health Available for 12 & 24 months recalls Signed consent/assent/HIPAA Criteria used to assess teeth for acceptance into this study: Teeth fully erupted, in functional occlusion and Radiographic evidence of early caries in interproximal areas Exclusion Criteria: Participation in other study History of adverse reaction on clinical material Sensitivity during screening test Poor access to teeth Patient refusing radiographic examination

Anusavice KJ. Present and future approaches for the control of caries. J Dent Educ. 2005 May;69(5):538-54.