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The present study focuses on the use of a metaproteomic approach to analyze Black Extrinsic Tooth Stains, a specific type of pigmented extrinsic substance. Metaproteomics is a powerful emerging technology that successfully enabled human protein and bacterial identification of this specific dental biofilm using high-resolution tandem mass spectrometry. A total of 1600 bacterial proteins were identified in black stain (BS) samples and 2058 proteins in dental plaque (DP) samples, whereas 607 and 582 human proteins were identified in BS and DP samples, respectively. A large diversity of bacteria genera (142) in BS and DP was identified, showing a high prevalence of Rothia, Kingella, Neisseria, and Pseudopropionibacterium in black stain samples. In this work, the high diversity of the dental microbiota and its proteome is highlighted, including significant differences between black stain and dental plaque samples., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Intracellular pH (pHi) and several ion transport mechanisms in cultured murine salivary gland cells (SCA-9) were studied using a videomicrofluorometric method and the H+-specific probe C-SNARF-1. The aim of this study was to test SCA-9 cells' pHi regulation mechanisms and evaluate if this cell line is representative of submandibular gland cells. Resting pHi in unstimulated cells was estimated to be 7.17+/-0.07. To investigate the presence of Na+/H+ and Cl-/HCO3- antiports as well as Na+/K+/2Cl- symports in SCA-9 cells, we used different specific blockers, dimethyl-amiloride, disulfonic stilbene, bumetanide and furosemide. In order to study SCA-9 cell capacity to regulate their pHi in response to alkaline and acid loads, we applied the NH4Cl prepulse method to all these blockers. The results showed that SCA-9 cells possess both antiports and symports involved in pHi regulation, and that this cell line can be used as a convenient model to study pHi regulatory mechanisms in salivary cells.

pH and salivary lactobacilli were analysed in 22 healthy individuals and 34 patients with cancer tumors of the oral or oropharyngeal regions before and during irradiation therapy. The findings revealed in cancer patients before radiotherapy, that pH and lactobacilli were significantly lower than those in non cancer control subjects. During irradiation therapy, pH and lactobacilli were not significantly altered. No significant difference was found between patients cured by chemotherapy before radiotherapy and patients treated only by irradiations. However, pH is modified by teeth: toothless patients ph and toothed patients pH change in opposite direction.