Verbesserung der Reproduzierbarkeit der Kariesdiagnostik mittels Widerstandsmessung und elektronischer Abschirmtechnik
Loading...
Files
Date
relationships.isAuthorOf
Publisher
Philipps-Universität Marburg
item.page.supervisor-of-thesis
Abstract
Problem definition and objective: Simultaneously with the decreasing caries prevalence, the clinical appearance of the occlusal caries has changed, which brings higher demands on the diagnosis. The occurrence of so-called "hidden caries" (also called occult caries or fluoride syndrome), which is attributed to the topical and systemic application of fluorides shows a visual clinical picture in which the enamel appears healthy, but the dentin is undermined by caries. Previous methods of electrical resistance measurement on the human tooth were particularly subject to the need for a defined drying, on the one hand to avoid electrical shunts in too wet teeth and on the other hand incorrect contacts with too dry teeth. In particular, the lack of reproducibility of the measured values and many false-positive test results prevented establishment of the previous methods. The aim of the present work was the development of a new technique that delivers highly reproducible results with clinically useful sensitivity and specificity independent of the oral cavity moisture level.
Material and method: A selection of 75 non-cavitated undamaged extracted molars and premolars were stored in artificial saliva adjusted to the electrical conductivity of natural saliva. For each tooth, three measurement points were selected along the central fissure and / or pits, which were reproducibly retrievable via a coordinate grid of digital photographs. The digital photos also served as visual diagnostic findings according to the ICDAS II procedure. All teeth were positioned in individually molded plastic holders in dappen dishes for measurements and dipped with their roots in the artificial saliva. The electrical resistance measurements were carried out in three methods by two investigators in five series of measurements, which were carried out at intervals of several weeks:
- Resistance measurement with an AC ohmmeter
- Resistance measurement using an agar-agar insulating gel
- Resistance measurement using an agar-agar insulating gel, the use of the new measuring technology and a measuring unit developed for this purpose consisting of a measuring electrode and a shielding electrode surrounding it in a circular manner to avoid electrical shunts caused by the moisture film on the tooth
The results were validated by CBCT and histological work-up. For statistical evaluation of the reproducibility, the rank correlation coefficient was determined according to Spearman (rs), scatter plots and Bland-Altman plots were created. As parameters of the diagnostic quality, values for sensitivity, specificity, likelihood quotients, ROC curves with the corresponding AUC values, as well as positive and negative predictive values and accuracy were determined. To compare the diagnostic procedures ICDAS II, electrical resistance measurements, digital volume tomography and histology, cross-tabulations were made. The software programs SPSS 24 and Microsoft Excel 2016 were used to calculate the statistics.
Results: For the reproducibility of the new measurement technique, an almost perfect correlation according to Spearman (intra-investigator reproducibility: rs = 0.913- 0.944, inter-examiner reproducibility: rs = 0.939) and corresponding visual representation of the very good reproducibility in the scatter and Bland Altman plots. For the D1 level (enamel and dentine caries) an average sensitivity value of 0.71 and an average specificity value of 0.98 was determined. The corresponding likelihood ratios showed values of LR (+) = 42.87 (excellent diagnostic evidence) and LR (-) = 0.30 (weak / moderate diagnostic evidence). The predictive values for the D1 level showed evident values of PPV = 0.965 and NPV = 0.790; the accuracy value was 87.35. As a result of the ROC analysis, Area Under the ROC Curve (AUC) values were 0.828 - 0.863 (good overall diagnostic accuracy). Caries prevalence here was 47.0 %. At D3 level (dentine caries), mean sensitivity and specificity values of 0.84 and 0.97, respectively, were obtained. The corresponding likelihood ratios for the D3 level showed values of LR (+) = 33.60 and LR (-) = 0.16 (in both cases interpreted as excellent diagnostic evidence). The result of the positive predictive value (PPV) here was 0.949, the negative predictive value (NPV) was 0.871. Accuracy at D3 level returned 92.95. The AUC values here were 0.907 - 0.923 (excellent overall diagnostic accuracy). The caries prevalence here was 37.4 %.
Discussion and conclusion: As part of the limitations of an in vitro study, it was shown that it is possible to develop an electronic resistance measurement method for (hidden) occlusal lesions by elimination of the disruptive factor "saliva" as a conductive electrolyte without defined drying of the tooth to be examined. Simultaneously this method provides diagnostic results at a clinically useful level that are highly reproducible. A use of the new technique for approximal lesions seems possible after first preliminary experiments. Further standardized studies on first and second dentition teeth in vitro and in vivo supporting the data collected in this study would be desirable.
Review
Metadata
Contributors
Supervisor:
Dates
Created: 2020Issued: 2020-02-04Updated: 2020-02-04
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
reproducibilityhidden cariesReproduzierbarkeitAbschirm-Treiber-Technikquantitative caries diagnosisElectrical resistance measurementfluoride syndrome
DFG-subjects
WiderstandsmessungDentinZahnschmelzKariesdiagnostikPulpa
DDC-Numbers
610
show more
Willamowski, Matthias: Verbesserung der Reproduzierbarkeit der Kariesdiagnostik mittels Widerstandsmessung und elektronischer Abschirmtechnik. : Philipps-Universität Marburg 2020-02-04. DOI: https://doi.org/10.17192/z2020.0024.