In vitro validation of near-infrared transillumination at 780 nm for the detection of caries on proximal surfaces

  • Alexander LedererEmail author
  • Karl-Heinz Kunzelmann
  • Katrin Heck
  • Reinhard Hickel
  • Friederike Litzenburger
Original Article



The aim of the present in vitro study was to determine the ability of Diagnocam to detect caries at an early stage and to compare it with digital radiography.

Materials and methods

One hundred twenty proximal surfaces composed equally of sound and decayed surfaces were evaluated by assessing images captured with Diagnocam (Kavo, Biberach, Germany) and digital radiography (DR). All images were assessed twice by two calibrated dentists with a minimum interval of 2 weeks between examinations. The results were compared with μCT scans.


Inter-rater reliability showed nearly perfect agreement; a high intra-rater reliability was calculated. Spearman’s rank correlation coefficients showed a strong correlation of Diagnocam and μCT (0.82). DR and μCT achieved a slightly lower correlation (0.73). The surfaces were categorized into sound surfaces, enamel lesions, and dentin lesions to determine intraclass correlation coefficients (ICCs), sensitivity and specificity. ICCs between μCT and DR ranged from 0.20 to 0.63. ICCs between Diagnocam and DR were higher in all categories and ranged from 0.56 to 0.83. Sensitivity, specificity, and accuracy of Diagnocam achieved mostly higher values than DR. In detecting enamel lesions, sensitivity was 0.36 for DR and 0.59 for the DC. The areas under the receiver operating characteristic (ROC) curves of Diagnocam were larger than those of DR in all categories.


Diagnocam is more capable of detecting initial proximal lesions than DR and also has a higher sensitivity for dentin lesions. However, caries progression in dentin cannot be reliably determined with Diagnocam.

Clinical relevance

Diagnocam may be suitable as a supplement to X-ray diagnostics in clinical use.


Transillumination Near-infrared light Proximal caries Caries detection X-ray microtomography In vitro 



The work was supported by the Department of Conservative Dentistry and Periodontology of the University Hospital of the LMU Munich.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors. All experimental procedures were approved by the Ethics Committee of the Faculty of Medicine of the Ludwig Maximilians University in Munich, Germany (488-15 UE).

Informed consent

For this type of study, formal consent is not required.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Conservative Dentistry and Periodontology, University HospitalLMU MunichMunichGermany

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