Detecting dental calculus is clinically challenging in dentistry. This study used typodonts with extracted premolar and molar teeth and simulated gingival tissue to compare the performance of differential reflectometry and periodontal probing. A total of 30 extracted teeth were set in an anatomical configuration in stone to create three typodonts. Clear polyvinyl siloxane impression material was placed to replicate the periodontal soft tissues. Pocket depths ranged from 10 to 15 mm. The three models were placed in a phantom head, and an experienced dentist assessed the presence of subgingival calculus first using the DetecTar (differential reflectometry) and then a periodontal probe. Scores from these two different methods were compared to the gold standard (direct examination of the root surface using 20× magnification) to determine the accuracy and reproducibility. Differential reflectometry was more accurate than tactile assessment (79% versus 60%), and its reproducibility was also higher (Cohen kappa 0.54 versus 0.39). Both methods performed better on single rooted premolar teeth than on multirooted teeth. These laboratory results indicate that differential reflectometry allows more accurate and reproducible detection of subgingival calculus than conventional probing, and supports its use for supplementing traditional periodontal examination methods in dental practice.