MEASUREMENT OF ENAMEL REMINERALIZATION USING MICRORADIOGRAPHY AND CONFOCAL MICROSCOPY - A CORRELATIONAL STUDY

Tooth minerals are lost and regained constantly in a normal, human ora l environment, Different methods have been developed to measure this g ain and loss in enamel minerals; however, these methods deal with diff erent problems, such as being time consuming or involving the use of X -rays, The aim of this study was to determine if remineralization meas ured in a thin enamel section (TS) by transversal microradiography (MR ) can be reliably monitored by measuring lesion parameters (area, tota l and average dye fluorescence) on the same TS or on half a tooth (HT) with confocal laser scanning microscopy (CLSM), Thirty-six human enam el specimens were demineralized for 96h, and then half of each specime n was covered with an acid-resistant nail varnish. Specimens were divi ded into three groups (12/group) and subjected for 20 days to a cyclic remineralization regimen with consisted daily of a 4-hour acid challe nge, four I-min treatment periods with 0, 250 or 1,100 ppm F dentifric e slurries (1:2; dentifrice:water) and 20 h in pooled, human saliva, a t room temperature. Specimens were cut and analyzed by MR, then staine d with a fluorescent dye (0.1mM rhodamine B) for 1h and analyzed using CLSM. Both MR and CLSM detected significantly greater remineralizatio n (p<0.05) in the specimens treated with the fluoride-containing denti frices than in the specimens treated with 0 ppm F. Significant differe nces were detected between specimens treated witht the fluoride-contai ning dentifrices by MR and CLSM (HT area and total fluorescence), Stat istically significant (p<0.05) Pearson correlation coefficients were c alculated between the MR and CLSM data: difference in MR mineral conte nt (Delta M) versus HT lesion area = 0.71; Delta M versus HT total flu orescence = 0.70; Delta M versus HT average fluorescence = 0.61; Delta M versus TS lesion area = 0.88; Delta M versus TS total fluorescence = 0.63, and Delta M versus TS average fluorescence = 0.40. It is concl uded that confocal microscopy in either TS or I-IT may provide valid s urrogates (area and total fluorescence) for MR measurements in enamel remineralization studies.