UCSF

Aims: The aims of this study were to test the hypothesis that PS-OCT can be used to nondestructively measure and quantify the severity of the early demineralization of buccal and occlusal enamel surfaces and assess the effect of fluoride varnish in inhibiting demineralization in vivo.

Material & Methods: Twenty subjects requiring bilateral premolar extractions were used. A cariogenic challenge was introduced by cementing orthodontic bands with a buccal window to these premolars and by making incisions on their occlusal surface. Bands were removed after 30 days and PS-OCT scans were acquired in vivo of occlusal and buccal areas. A split mouth design was used to test the effects of fluoride varnish. Teeth were extracted, serial sectioned and analyzed using Polarized Light Microscopy and Microradiography for comparison with the PS-OCT images.

Results: High quality PS-OCT images were acquired in vivo, with excellent optical penetration through the sound enamel to the dentin. Both occlusal and buccal surfaces showed a significant difference between the "sound" and "carious" enamel groups. The "sound" group had an average ΔR = 67.72 dB * μm, and the "carious" group had an average ΔR = 206.64 dB * μm. Both PLM and PS-OCT lesion depth measurements showed a significant difference between the "sound" and "carious" enamel groups for the occlusal surface, but not for the buccal surface, when calculated with PS-OCT. There was not a significant difference between the fluoride varnish and control groups in both TMR and PS-OCT tests.

Conclusion: This is the first clinical study to show the great potential of PS-OCT as a clinical tool, to nondestructively measure the depth and severity of early enamel demineralization including the high risk areas of occlusal surfaces and around orthodontic appliances, and to assess the efficacy of chemical intervention. With further studies, PS-OCT can prove to be valuable in the clinical setting due to its: ease of use, high contrast of early detection compared to traditional x rays or visual evaluation, and value of early detection in taking preventive action.

This work was supported by NIDCR Grant# R01-17869.