A simplified method for detecting Gram-positive and Gram-negative bacteria in dental histological samples: A preliminary and comparative study

P. Savadori, S. Dalfino*, M. Piazzoni, M. Parrini, M. Del Fabbro, G.M. Tartaglia, L. Giardino

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Web of Science)


Objective: Bacteria identification inside the dental tissue is a complex procedure requiring specific protocols. This study aimed to compare two classical Gram staining methods with a new staining method proposed by the authors to detect Gram-positive and Gram-negative bacteria in dental histological samples of human dentin.Methods: Ten human teeth, extracted because of various pathologies, were decalcified, dehydrated, and paraffinembedded. Then, approximately 100 serial sections of 4 mu m thickness were made per sample. The serial sections were placed on glass slides and were stained according to Brown-Brenn, Brown-Hopps, and a proposed modification of Brown-Brenn staining. Both ATCC strains, smeared on glass slides, were stained following each method's instructions used in histological samples.Results: From a qualitative evaluation, the Brown-Brenn method resulted in better staining of Gram-positive bacteria, while the authors' proposed staining technique was more oriented towards Gram-negative bacteria. On the other hand, the Brown-Hopps showed quite a balance in detecting Gram-positive and Gram-negative bacteria. Unlike the Brown-Brenn stain, the other two protocols showed better stainability of Gram-negative microorganisms in bacterial-smeared samples.Conclusion: All staining techniques evaluated in this article can identify bacteria, but the outcome can change according to the staining procedure used.
Original languageEnglish
Article number151992
Number of pages7
JournalActa Histochemica
Issue number1
Publication statusPublished - 1 Jan 2023


  • Bacteria
  • Dental tubules
  • Histology
  • Histological staining

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