Detektion von initialen Demineralisationen in Schmelz an Glattflächen und am Rande von Brackets mittels eines neuartigen Kariesindikators – Eine in vitro Studie

Background and objective: Caries of permanent teeth is the most common disease worldwide. Patients undergoing orthodontic treatment have proven to be a special risk group. The probability of developing an initial carious lesion during treatment is significantly increased in this patient group. Early detection is important for the use of preventive and remineralising procedures. In the present study, the staining behavior of the novel caries indicator BlueCheck was tested on smooth surfaces with artificially created initial lesions. For this purpose, smooth surfaces with and without brackets were examined. Material and method: For the study, smooth surfaces of 60 tooth specimens of extracted human teeth were used. The central surface of 30 samples was ground and polished. In another 30 samples, brackets were adhesively bonded to unpolished surfaces. As part of the basic tests, the BlueCheck solution was applied to all samples and examined. Acid-resistant nail varnish was applied to all specimens as an internal control. Half of the specimens (15 with and 15 without brackets) were artificially demineralized (lactic acid, pH 4.6) for seven days, the other half for 14 days. The created initial demineralization was checked and quantified in terms of fluorescence loss (ΔF) and lesion volume (ΔQ) using the reference standard of quantitative light-induced fluorescence measurement (QLF, QraycamTM Pro camera and software C4 QLFTM Research Suite programme). The samples were stained again and the staining behavior was documented. The evaluation of the staining after BlueCheck application was performed by two examiners as a yes/no decision. In addition, histological tooth sections were prepared on a representative sample and the depth of the lesion was determined. The statistical analysis of the QLF data was performed with MedCalc. The data were checked for normal distribution using the Shapiro-Wilk test. The analysis of the independent data was performed using the Kruskal-Wallis test. The depth of the lesions on the histological sections was determined using the program Image J. Results: Initially, none of the tooth samples examined showed enamel discoloration after the first BlueCheck application. After demineralization, all samples showed blue discoloration during BlueCheck application, regardless of demineralization time.In the QLF examination, initial demineralization was detected in all groups (median ΔF = -8.25%, mean ΔF = -8.69%, SD = ±2.28%). The maximum fluorescence loss (median ΔFmax = -17.6%, mean ΔFmax = -18.31%, SD = ±8.12%) and the lesion volume (ΔQ = -2,619.5% x px2, median ΔQ = -4,285.6% x px2, SD = ±4,862.21% x px2) were examined. In the Kruskal-Wallis test, no significant difference between fluorescence loss at 7 and 14 days of demineralization was detected (p = 0.13). The mean values for histologic lesion depth ranged from 199.6μm to 253.5μm. BlueCheck demonstrated 100% agreement between demineralization and blue staining. This was confirmed by a side-by-side comparison of the sound and demineralized enamel areas. Discussion and conclusion: In this in vitro study very good results for the staining behavior of BlueCheck on smooth surfaces and at the margins of brackets were shown. As far as further clinical investigations confirm the present results, BlueCheck can be recommended as an easy-to-use caries indicator for monitoring dental health during orthodontic treatment, but also for early caries detection as part of group prophylactic measures.