Background/Objectives: The aim of this in vivo study was to compare the diagnostic performance of conventional methods, including visual examination according to the International Caries Detection and Assessment System II (ICDAS II) and digital bite-wing radiography, with laser fluorescence (DIAGNOdent Pen) and near-infrared transillumination (DIAGNOcam and VistaCam iX-Proxi head) for the detection of non-cavitated approximal caries and to evaluate inter-examiner agreement. Methods: A total of 76 non-cavitated posterior teeth/surfaces from patients aged 15–60 years were independently assessed by three investigators. Enamel caries validation was based on combined ICDAS II and bite-wing radiographic findings, whereas dentin caries validation was established by cavity opening and direct clinical assessment. Diagnostic performance was evaluated using sensitivity, specificity, predictive values, accuracy, and receiver operating characteristic analysis. Inter-examiner agreement was assessed using the kappa coefficient, and diagnostic performance was compared using the McNemar test (p < 0.05). Results: Sensitivity ranged from 7.5% for visual examination to 94.3% for DIAGNOdent Pen, whereas specificity ranged from 12.6% to 100.0%. Bite-wing radiography demonstrated the highest diagnostic performance (accuracy: 87.7%; AUC: 0.775), followed by DIAGNOcam (accuracy: 86.0%; AUC: 0.738) and VistaCam (accuracy: 84.2%; AUC: 0.720). Although DIAGNOdent Pen showed high sensitivity, its specificity and overall accuracy were low (31.6%; AUC: 0.535). Inter-examiner agreement was substantial for visual examination, bite-wing radiography, and DIAGNOcam, moderate for VistaCam, and slight for DIAGNOdent Pen. Conclusions: Within the limitations of this study, combining visual examination, digital bite-wing radiography, and near-infrared transillumination methods may improve the detection of approximal caries, particularly at an early stage.

Deep margin elevation (DME) relocates deep subgingival restorative margins, but biomechanical differences among resin composite types and DME configurations remain unclear. This study compared three resin composites in modeled 1 and 2 mm DME configurations in an endodontically treated maxillary second premolar using three-dimensional finite element analysis. Eight models were analyzed: an intact tooth, a restored reference model, and six DME configurations using Tetric EvoFlow, Filtek Supreme XTE, or Filtek Z100 beneath a lithium disilicate restoration. A 34 MPa distributed occlusal pressure and a 50 N static force were applied simultaneously. Principal stresses were assessed for enamel and lithium disilicate, whereas von Mises stress (VMS) was evaluated for dentin, DME composite, and resin cement. Tensile strength-based screening, threshold-exceeding volume fractions, path-based displacement, and ESTRN were also evaluated. Compared with corresponding 1 mm configurations, 2 mm configurations showed lower enamel tensile stress by 16.1–32.6%, enamel compressive stress magnitude by 16.2–32.4%, dentin VMS by 20.1–33.5%, and DME composite VMS by 8.5–8.7%. Lithium disilicate stresses generally decreased, whereas resin cement showed a material-dependent response. Displacement was generally higher in 2 mm configurations, while maximum ESTRN generally decreased in enamel, dentin, DME composite, and lithium disilicate. Threshold-exceeding enamel volumes ranged from 0.14% to 1.87%; only M5-FZ100-1 exceeded 124 MPa in IPS e.max CAD, involving 0.04% of the restoration volume. Under the modeled conditions, biomechanical responses differed between 1 and 2 mm DME configurations and among composite types, without establishing overall superiority of any material or configuration.