Antimicrobial Photodynamic Therapy (aPDT) for decontamination of high-speed handpieces: A comparative study.

BACKGROUND: Cross-transmission is a major concern in dental offices. Various disinfection methods have been frequently used to reduce its incidence. Standard procedures include decontamination and sterilization. Traditional decontamination methods include: Alcohol 70 % and chlorhexidine digluconate, however, antimicrobial photodynamic therapy (aPDT) could be added as an option. The objective was to evaluate the effectiveness of aPDT on decontamination of high-speed handpieces, contaminated by Staphylococcus aureus (SA) and Escherichia coli (EC), and compare it to autoclave sterilized and to conventional chemical decontamination methods. METHODS: Sterilized, SA and EC contaminated high-speed handpieces were divided in 7 groups: G1- sterilized in an autoclave. G2- contaminated untreated control. G3- contaminated and decontaminated using Alcohol 70 %. G4- contaminated and decontaminated using chlorhexidine digluconate 2%. G5- contaminated and laser treated. G6- contaminated and photosensitizer treated. G7- contaminated and photodynamic therapy. RESULTS: The groups G3, G4, G7 did not show bacterial growth, G5 and G6 showed bacterial growth similar to G2. The study did not find SA or EC sensible to laser irradiation only, differently from some authors and did not consider biofilm in our experiments. CONCLUSION: Our experiment showed that, laser and photosensitizer isolated were not effective to inhibit Staphylococcus aureus (SA) and Escherichia coli (EC) growth, but when associated in aPDT technique, can be compared to chemical disinfection agents that are traditionally used and effective against this pathogen.

miR-2861 is involved in osteogenic commitment of human periodontal ligament stem cells grown onto 3D scaffold.

miR-2861 endorsing osteoblast differentiation through the overexpression of Runt-related transcription factor 2 (RUNX2) protein has been recently described. In this study we evaluated: the performance of living construct, composed by human Periodontal Ligament Stem Cells (hPDLSCs) and 3D scaffold (EXg), and the behaviour of miR-2861/RUNX2 expression pathway on the osteogenic commitment. Human PDLSCs were seeded with and without EXg scaffold and cultured under basal and osteogenic conditions. Morphological features, adhesiveness and differentiation abilities were analysed using scanning electron and confocal laser scanning microscopy. Time-course of RUNX2, ALP, OPN and miR-2861 were evaluated through RT-PCR analysis. Our results highlighted that the osteogenic differentiation was mostly obvious in the hPDLSCs, grown onto 3D scaffold in presence of osteoinductive medium. Moreover, the overexpression of miR-2861 and RUNX2 in hPDLSCs cultured in presence of EXg under osteogenic and standard conditions was demonstrated. In synthesis, the increased expression of miR-2861/RUNX2 provides new insights regarding miRNA signaling network in the presence of scaffold providing an additional method to evaluate the performance of biomaterial in bone regeneration.

The relationship between tumour size and expression of prognostic markers in benign and malignant canine mammary tumours.

Tumour size is considered one of the most important determinants of clinical staging in cancer patients. The aim of this study was to assess the value of tumour size as an indicator of the differentiation of mammary neoplasias in female dogs. The tumour, nodes metastates (TNM) system, based on primary lesion size, the extent of its dissemination to regional lymph nodes and the presence or absence of distant metastases, was applied to 120 female dogs diagnosed with mammary neoplasias. Paraffin blocks from 38 cases were selected and studied by immunohistochemical staining for prognostic and predictive markers of breast cancer. The Kaplan-Meier survival curve was estimated for 110 female dogs. Larger tumours (T3) were mostly malignant and showed lower expression of progesterone receptor and higher expression of cellular proliferation markers. Global survival time was shorter in female dogs with large tumour masses. This study highlights the importance of tumour size as a prognostic indicator of mammary neoplasias in female dogs.