In this study, microbial diversity of the root canal microbiota related to different endodontic infections was investigated. In total, 45 patients with endo–perio lesions (8 patients), chronic periapical periodontitis (29 patients) and pulp necrosis (8 patients) were recruited. In 19 (42.2%) patients there was secondary infection of root canals. Microbial specimens were collected from root canals of non-vital teeth with or without changes in periapical area visible in X-ray. Then, oral microbiota were detected and identified using the culture method and real-time PCR amplification primers and hydrolysis-probe detection with the 16S rRNA gene as the target. Overall, 1434 species/genes from 41 different genera of 90 various microbial species were retrieved. Of the major reported phyla, Firmicutes (62.9%), Actinobacteria (14.0%), Bacteroidetes (12.1%), Proteobacteria (9.1%) and Fusobacteria (4.2%) were detected. Of the bacterial species, 54.6% were strict anaerobes. Corynebacterium matruchotii (p = 0.039) was present significantly more frequently in chronic periapical periodontitis. Moreover, the higher values of Decayed, Missing and Filled Permanent Teeth index were positively correlated with relative abundance of Actinomyces spp. (p = 0.042), Lactobacillus spp. (p = 0.006), Propionibacterium spp. (p = 0.024) and Rothia spp. (p = 0.002). The multivariate analyses revealed differences in total root canal samples, where components that affected grouping of root samples into four main categories were identified. Anaerobic Gram-negative bacteria predominated in root canals of teeth with pulp necrosis and periapical lesions. Facultative anaerobic Gram-positive bacteria predominated in canals with secondary infections. All detected members of mixed population groups that might serve as keystone species contributed to the entire community in its clinical relevance.

In search of an effective antibacterial agent that is useful in photodynamic therapy, new derivatives of zirconium(IV) phthalocyanine (ZrPc) complexes were obtained and linked to graphite oxide flakes. In the syntheses of ZrPc derivatives, two bis-axially substituted ligands with terminal amino group and different lengths of linear carbon chain (C4 in 4-aminobutyric acid or C11 in 11-aminoundecanoic acid) were used. The optical properties (absorption and photoluminescence spectra) of ZrPcs and the composites were examined. Broadband red–near-infrared lamp was tested as an external stimulus to activate ZrPcs and the composites. Optical techniques were used to show generation of singlet oxygen during irradiation. Considering the application of graphite oxide-based materials as bacteriostatic photosensitive additives for endodontic treatment of periapical tissue inflammation, the antibacterial activity was determined on one Escherichia coli strain isolated directly from an infected root canal of a human tooth and one strain with silver and antibiotic resistance. Looking at the obtained results, modified levels of activity toward different bacterial strains are discussed.

The diagnostic management is a very important and integral part of the entire treatment process and has a direct influence on the decision-taking on the choice of the most appropriate form of therapy consistent with current knowledge. Knowledge of the morphology of hard dental tissues lesions has led to the development of quantitative methods for diagnosis and monitoring of dental caries, which enabled the implementation of appropriate treatments aimed at repairing than replacing damaged tissue. The aim of the study was to compare selected diagnostic methods: visual (ICDAS), impedance spectroscopy (CarieScan PRO) and laser fluorescence (Diagnodent Pen) in detecting caries in grooves on the chewing surfaces of molars and premolars. The obtained results indicated a high concordance of measurements performed with the Diagnodent Pen with the results of visual examination and a lower compliance of visual examination with the results obtained using the CarieScan PRO. A combination of visual and tactile method with tests using advanced technology provides greater opportunity to confirm the diagnosis of carious lesions requiring medical intervention.

Many studies have shown that the accurate diagnosis before cavitation occurs could reduce need for drilling and filling. Among many techniques, measurement of electrical resistance (impedance) of dental tissues looks promising. The role of AC-impedance spectroscopy in caries detection is discussed and a relatively new device CarieScan PRO™ based on this phenomena is described. Changes in tooth mineral density detected by this tool as numerical and color codes are distinguished.