Surface morphology of sound deciduous tooth enamel after application of a photo-absorbing cream and infrared low-level laser irradiation: an in vitro scanning electron microscopy study.
OBJECTIVE
The purpose of this descriptive scanning electron microscopic study was to characterize surface alterations in deciduous tooth enamel after in vitro infrared diode laser irradiation, using a photo-absorbing agent alone and also combined with fluoride, before and after laser irradiation.


BACKGROUND
Previous investigations have demonstrated increased enamel caries resistance after laser irradiation.


METHODS
Seven extracted or exfoliated primary molar teeth underwent soft tissue débridement and fluoride-free prophylaxis. Buccal surfaces were determined to be caries free by macroscopic examination. Sample groups were divided into: (1) control (no treatment); (2) infrared diode laser irradiation (lambda = 810 nm, 68 nm, 60 mW/mm(2), 30 W) using the photo-absorbing agent alone (IRDL + PA; 500 J/cm(2)); and (3) infrared diode laser irradiation using a photo-absorbing agent combined with 2% fluoride (IRDL + PFA; 500 J/cm(2)). Buccal surfaces were evaluated following standard scanning electron microscopy preparation techniques. Control samples of enamel surfaces were relatively smooth but presented occasional enamel prism ends. There were no areas with cavitations or surface defects.


RESULTS
After the IRDL + PA treatment, irradiated surfaces became rough and mildly to moderately irregular with scarce enamel cavitations and without exposure of enamel prism ends. The surfaces had adherent granules and only occasional fine cracks and porosities in surface coatings were noted. After the IRDL + PFA treatment, there was a homogenous confluent surface that masked typical enamel surface markings. The surfaces had well-defined globules resulting from the IRDL + PFA treatment, that were not seen after IRDL + PA treatment.


CONCLUSIONS
Treatment of deciduous tooth enamel with infrared diode laser irradiation using a photo-absorbing agent and a photo-absorbing agent combined with 2% fluoride created surface coatings that may act as reservoirs for mineral phases during cariogenic activity on enamel, and also provide a certain degree of protection against cariogenic challenge.
D000042:Absorption; D002327:Cariostatic Agents / Q000008:administration & dosage; D004396:Coloring Agents / Q000008:administration & dosage*; D003743:Dental Enamel / Q000528:radiation effects* / Q000648:ultrastructure*; D005460:Fluorides, Topical / Q000008:administration & dosage; D006801:Humans; D007208:Indocyanine Green / Q000008:administration & dosage*; D028022:Low-Level Light Therapy; D008855:Microscopy, Electron, Scanning; D014094:Tooth, Deciduous / Q000528:radiation effects* / Q000648:ultrastructure*
D002327:Cariostatic Agents; D004396:Coloring Agents; D005460:Fluorides, Topical; D007208:Indocyanine Green