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Purpose: Diets rich in nitrates have the potential to prevent oral diseases such as caries or periodontitis. The reduced forms nitrite and nitric oxide have an antibacterial effect against cariogenic bacteria. The effect on bacterial acid production in saliva and oral biofilm is yet unknown. This study investigated the influence of consuming naturally nitrate-rich beetroot juice on bacterial lactate production in saliva and on the pH value of saliva and oral biofilm. Materials and Methods: In addition to their usual diet, a study group of eight subjects consumed 50 ml of beetroot juice daily for a fortnight. After a two-week break, they rinsed with 0.2% chlorhexidine (CHX) for 14 days as a positive control. Bacterial lactate production was induced by rinsing with 50 ml apple juice and measured at different time points during the study. Results: After two weeks of daily beetroot-juice consumption, an accumulation of nitrate and nitrite was measured in the saliva. No influence on the bacterial lactate production in saliva or the saliva and plaque pH was found. Conclusion: Commercially available beetroot juice showed no modulating effects on intraoral bacterial acid production, suggesting no caries-preventive properties under the tested conditions. [ABSTRACT FROM AUTHOR]

The aim of the study was to establish a live/dead qPCR with propidium monoazide (PMA) that can quantitatively differentiate between viable/non-viable microorganisms in dental hard tissues. Human premolars (n = 88) were prepared with nickel–titanium instruments and incubated with E. faecalis (21 d). Subsequently, the bacteria in half of the teeth were devitalized by heat inactivation (100 °C, 2 h). The following parameters were tested: PMA concentrations at 0 µmol (control), 50 µmol, 100 µmol, and 200 µmol; PMA incubation times of 30 min and 60 min, and blue light treatment for 30 min and 60 min. The teeth were ground using a cryomill and the bacterial DNA was quantified using qPCR, ANOVA, and p = 0.05. The qPCR of the control group detected a similar number of avital 9.94 × 106 and vital 1.61 × 107 bacterial cells. The use of PMA inhibited the amplification of DNA from non-viable cells during qPCR. As a result, the best detection of avital bacteria was achieved with the following PMA parameters: (concentration, incubation time, blue light treatment) 200-30-30; 5.53 × 104 (avital) and 1.21 × 100.7 (vital). The live/dead qPCR method using PMA treatment is suitable for the differentiation and quantification of viable/non-viable microorganisms in dentin, as well as to evaluate the effectiveness of different preparation procedures and antimicrobial irrigants in other biological hard substances. [ABSTRACT FROM AUTHOR]

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Early caries diagnosis still challenges dentistry. Polarization-sensitive optical coherence tomography (PS-OCT) is promising to detect initial lesions non-invasively in depth-resolved cross-sectional visualization. PS-OCT with determined degree of polarization (DOP) imaging provides an intuitive demineralization contrast. The aim of this study is to evaluate the suitability of DOP-based PS-OCT imaging to monitor controlled de- and remineralization progression for the first time and to introduce it as a valid, non-destructive in vitro detection method. Twelve standardized bovine enamel specimens were divided in different groups and demineralized with hydrochloric acid (HCl) as well as partly remineralized with fluoride over a 14-day pH-cycling experiment. The specimens were stored in artificial saliva and sodium chloride (NaCl), respectively. Progress measurements with PS-OCT were made with polarization-sensitive en faceand B-scan mode for qualitative evaluation. The specimens demineralized in HCl showed the most pronounced surface change (lowest DOP) and the most significant increase in depolarization. Additional fluoride treatment and the storage in artificial saliva resulted in the opposite (highest DOP). Therefore, DOP-based PS-OCT imaging appears to be a valuable technique for visualization and monitoring of enamel demineralization and remineralization processes in vitro. However, these findings need to be confirmed in human teeth ex vivo or in situ. [ABSTRACT FROM AUTHOR]

Oral health is a crucial aspect of overall well‐being in both humans and nonhuman primates. Understanding the oral pathologies and dental conditions in apes can provide valuable insights into their evolutionary history, dietary habits, and overall health. The present study evaluates dental findings in wild great apes from museum specimens to gain insights into the influence of natural nutrition on dental health. Complete macerated skulls of wild, adult great apes from the collection of the Museum of Natural History, Berlin, Germany, were examined. We analyzed skulls of 53 gorillas (Gorilla gorilla), 63 chimpanzees (Pan troglodytes), and 41 orangutans (Pongo spp.). For each skull, we recorded wear of dental hard tissues (Lussi and Ganss index), carious lesions, and periodontal bone loss. Incisal and occlusal dental hard tissue defects were found in all skulls, as well as considerable external staining. In all species, incisors and canines showed the greatest loss of tissue, followed by molars. The wear of molars decreased from the first to the third molars, premolars showed the least pronounced defects. Some individuals had apical osteolytic defects along with severe dental hard tissue loss with pulp involvement or after dental trauma, respectively (n = 5). Our study did not observe any carious lesions among the examined great ape skulls. However, we did find evidence for localized or generalized periodontal bone loss in a subset of the specimens (n = 3 chimpanzees, n = 7 orangutans). The natural diet and foraging behavior of great apes induces abrasion and attrition of dental hard tissue but does not yield carious lesions. The occurrence of periodontitis in individual apes indicates that the natural circumstances can induce periodontal bone loss even in the wild, despite physiological nutrition. Research Highlights: The natural diet and foraging behavior of great apes induces wear of dental hard tissues but not carious lesions.The occurrence of periodontitis in individual apes indicates that the natural microbiome, in conjunction with the host's defense, can induce periodontal bone loss even in the wild. [ABSTRACT FROM AUTHOR]

Models of artificial root canals are used in several fields of endodontic investigations and pre-clinical endodontic training. They allow the physical testing of dental treatments, the operating of instruments used and the interaction between these instruments and the tissues. Currently, a large number of different artificial root canal models exist whose geometry is created either on the basis of selected natural root canal systems or to represent individual geometrical properties. Currently, only a few geometric properties such as the root canal curvature or the endodontic working width are taken into consideration when generating these models. To improve the representational capability of the artificial root canal models, the aim of the current study is therefore to generate an artificial root canal based on the statistical evaluation of selected natural root canals. Here, the approach introduced by Kucher for determining the geometry of a root canal model is used, which is based on the measurement and statistical evaluation of the root canal center line's curvatures and their cross-sectional dimensions. Using the example of unbranched distal root canals of mandibular molars ( n = 29), an artificial root canal model representing the mean length, curvature, torsion and cross-sectional dimensions of these teeth could be derived. [ABSTRACT FROM AUTHOR]

(1) Caries and erosions still remain a challenge for preventive dentistry. Certain plant extracts have shown beneficial effects in preventive dentistry. The aim of this study was to evaluate the antibacterial, anti-adherent and erosion-protective properties of ellagic acid (EA) as a polyphenolic agent. The combination with olive oil was investigated additionally to verify a possible improved bioactive effect of EA. (2) An in situ study was carried out with six subjects. Individual splints were prepared with bovine enamel specimens. The splints were worn for 1 min (pellicle formation time). Thereafter, 10 min rinses were performed with EA in water/in oil. Bacterial adherence was evaluated by fluorescence microscopy (DAPI, ConA, BacLight) after an 8 h oral exposition time. Additionally, the splints were worn for 30 min to quantify demineralization processes. The ultrastructure of the pellicle was investigated after an oral exposure time of 2 h under a transmission electron microscope. Statistical analysis was performed by Kruskal–Wallis tests, Mann–Whitney U tests and Bonferroni–Holm correction. (3) Rinsing with EA led to a significant reduction of adherent vital and dead bacteria. The combination with olive oil did not improve these outcomes. The assessment of glucan structures after rinsing with EA in water showed significant effects. Significant differences were observed for both rinses in calcium release at pH 3.0. After rinsing with EA in oil, significantly less calcium was released compared to rinsing with EA in water (pH = 3.0). (4) Olive oil is not suitable as a transport medium for lipophilic polyphenols. EA has anti-adherent and antibacterial properties in situ. EA also shows erosion-protective effects, which can be enhanced in combination with olive oil depending on the pH value. Ellagic acid has a neutral pH and could be an opportunity in the treatment of specific patient groups (xerostomia or mucositis). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antimicrobial efficacy of different disinfection protocols in a novel Enterococcus faecalis biofilm model based on a visualization method and to evaluate the potential alteration of dentinal surface. A total of 120 extracted human premolars were allocated to 6 groups with different irrigation protocols. The assessment of the effectiveness of each protocol and the alteration of dentinal surface were visualized by using SEM and fluorescence microscopy (DAPI). A dense E. faecalis biofilm with a penetration depth of 289 μm (medial part of the root canal) and 93 μm (apical part) validated that the biofilm model had been successfully implemented. A significant difference between the 3% NaOCl groups and all the other groups in both observed parts of the root canal (p < 0.05) was detected. However, the SEM analysis revealed that the dentinal surface in the 3% NaOCl groups was severely altered. The established biofilm model and the visualization method based on DAPI are appropriate for bacterial quantification and evaluation of the depth effect of different disinfection protocols in the root canal system. The combination of 3% NaOCl with 20% EDTA or MTAD with PUI allows the decontamination of deeper dentine zones within the root canal but simultaneously alters the dentinal surface. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate the direct and indirect influence of fluoridated toothpastes and fluoride‐free toothpaste with hydroxyapatite (HAP) as active ingredient on initial bacterial colonization on enamel in situ. Methods: For this clinical‐experimental pilot study, eight subjects were instructed to brush their teeth with three different toothpastes (Elmex®: 1400 ppm AmF, Meridol®: 1400 ppm AmF +SnF2, Karex®: HAP), using each for two consecutive days. As a control, brushing without toothpaste was performed. To evaluate bacterial colonization, subject wore splints with buccally placed bovine enamel platelets overnight. Two modes were tested. In a first pass (regimen A), the splints were inserted after toothbrushing to examine the indirect effects of the dentifrices. In order to investigate the direct effects, the specimens were brushed in situ in a second pass (regimen B). Biofilm formation was visualized and quantified using fluorescence microscopy (DAPI and BacLight) and transmission electron microscopy (TEM). Results: For brushing regimen A (indirect effect of dentifrices), no statistical differences were detected between any of the tested dentifrices or the control. Likewise, no statistically significant differences were recorded for brushing regimen B (direct effect of dentifrices). Furthermore, no differences between the different brushing techniques were determined with regard to the ultrastructure of the overnight biofilm. Conclusion: Within the limitations of the present pilot study, it can be concluded that in patients with good oral hygiene, dentifrices and their chemical composition have no statistically significant effect on the initial bacterial colonization of enamel platelets in situ, irrespectively of the mode of application. [ABSTRACT FROM AUTHOR]