In vivo analysis of traditional amalgam restorations placed on the film holder (Jon, São Paulo, SP, Bra- The presence of a radiolucent area surrounding zil) which was then placed on the occlusal surface the restoration margins (indicative of secondary of the experimental tooth and its antagonist to caries) was observed in the final radiograph. In ad- form an impression of the anatomy of this surface. dition, the dentin thickness between the pulp and It was, therefore, possible to relocate the device GIC liner was recorded in both radiographs (base- in the same position in the different experimental line and final). periods.20 Kodak E-Speed films (Eastman Kodak Statistical Analysis Co., New York, USA, lot number 3107662) were Analysis of variance (ANOVA) for repeated mea- used and radiographs were taken using the same surements and Tukey test were performed to com- mobile X-ray source (Timex 70C mobile column, pare the amount of mineral in dentin before and Gnatus; exposure time: 0.64 s). The radiographs after cavity preparation and after the 12-month were processed manually in Kodak developing observation period. Dentin color after cavity prep- (lot number 0637 C6 02687) and fixing (lot number aration and after 12 months was compared by 0714 B6 02251) solutions using the following tem- means of the paired Student’s-t test. Spearman’s perature/time combination: 2 min in the developer correlation test was performed to associate den- and 4 min in the fixer at a temperature of 26oC. tin color with the amount of mineral in dentin. All All procedures were performed by a single profes- the above-mentioned tests were performed at a sional. significance level of 5%. Descriptive statistics was Monitoring the Restorations performed to characterize recurrent caries attack After the 12-month follow-up period, all indi- after 12 months by either clinical visual or radio- viduals were scheduled for re-evaluation. Clinical graphic examination. Dentin thicknesses were examination executed and a bitewing radiograph compared using descriptive statistics. was taken using the same film holder of the im- pression initially defined. Similar X-ray source and RESULTS film processing conditions as those used at base- Dentin Mineral Content line were applied. Means and standard deviations emitted by the The teeth were anesthetized and a rubber dam DIAGNOdent device are shown in Figure 1. There was placed. Amalgam and GIC were removed by was statistically difference between mineral con- the same operator, using a #245 carbide bur (KG tent of dentin in all evaluated periods (P<.001), Sorensen) in order to assess the dentin under- showing the highest value before caries removal neath these materials. This direct visualization is and the lowest after 12 months. the gold-standard method for evaluating recurrent Dentin Color caries (soft dentin) and dentin color visually, and There was no statistical difference (P=.07) be- mineral content by DIAGNOdent. The presence of tween dentin color means after cavity preparation soft dentin (typical in active recurrent caries) was (1.73 ± 0.64) and after 12 months (1.9 ± 0.66). observed by clinical examination. Moreover, dentin Dentin Color versus Dentin Mineral Content color at the pulp wall was recorded using the pre- There was no correlation between dentin color viously described scores19 and a laser-induced and dentin mineral content (P=.74; r2 = -0.33). fluorescence reading with DIAGNOdent was per- formed under similar conditions to those used at Recurrent caries baseline. After this, tooth was refilled using clini- After 12 months, no recurrent caries was ob- cal steps similar to those used at baseline. served either by clinical visual or radiographic ex- aminations. Baseline and 12-month (final) radiographs were codified and analyzed in a dark room. A sin- Remaining Dentin Thickness gle calibrated examiner (kappa 0,91) performed There was no increase or decrease in remain- this exam with a negatoscope, a 2x magnifying ing dentin thickness after 12 months when com- glass (Maped do Brasil, São Paulo, SP, Brazil) and pared with the baseline observation (1.72 mm ± a millimeter ruler (Prisma, São Paulo, SP, Brazil). 0.49 mm). 266 European Journal of Dentistry