Harnessing the power of biologic agents on the oral microbiota: a way to promote oral and systemic health?

During the long history of their evolution, higher organisms, including mammals, have learnt to take great advantage from living in close contact with selected populations of microbes.1 By living in close contact, animals and microbes underwent a progressive and mutual co-evolutive process that is believed to be a major driving force in the development of adaptive immunity of vertebrates.2 As a result of this co-evolutive process, humans and other animals are characterized by their own unique microbiomes, each consisting of many hundred species of viruses, bacteria, archaea, fungi, and protozoa, unevenly distributed to colonize the different accessible regions of the body.3 The human microbiome is believed to account for 1-3% of body weight and to comprise more than 100 trillion cells.4 The microbiota is involved in complex host-microbe and microbe-microbe interactions, thus modulating nutrient acquisition, adjusting immune system development and general homeostasis (via epigenetic modifications of host genes5), and playing the role of protective barrier to pathogens.4 When a microbiota undergoes qualitative and quantitative changes with regard to distribution in a site and metabolic activity, this condition is defined dysbiosis and is expected to be associated with local and/ or distant pathologic signs.6 Bacterial products released by a dysbiotic microbiota interact with homeostatic mechanisms of the human host and cooperate to the pathogenesis of major human diseases, including diabetes mellitus, inflammatory bowel syndrome, atherosclerosis, obesity, liver disease, and cancer.4,7 he oral microbiota is the second more abundant and one of the most diverse and unique microbial communities in the human body.8 Although many of the most relevant oral and dental diseases, including caries, periodontal and peri-implant diseases, have been long recognized as of microbial origin, only recently the application of culture independent molecular methods using 16S rRNA gene comparative analyzes enabled us to understand that they are caused by dysbiosis rather than by the action of specific pathogens.9-11 The effects of oral dysbiosis are not limited to oral tissues: periodontal diseases, for example, are among the most common human diseases and their associations with diabetes, cardiovascular disease, metabolic disease and obesity, rheumatoid arthritis, certain cancers, respiratory diseases, and cognitive disorders is now supported by increasing evidence.12 Recent molecular investigations showed that some potentially pathogenic oral bacteria (named pathobionts), as for example Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum, colonize in low numbers the oral cavity of healthy individuals, without alerting sentinel systems of mucosal defences.13,14 Conditions able to disrupt the eubiotic equilibrium promote the overgrowth of pathobionts, which suddenly become pathogens (with support from commensal

Zinc oxide non-eugenol cement versus resinous cement on single implant restoration: a split-mouth study

Cement-retained implant restorations still represents a widely used prosthetic solution today, considering the simple execution, the possibility of correcting the implant axis according to the dental axis and an extremely satisfactory aesthetic. The objective of the study is to evaluate whether resin-based cements are actually more aggressive towards the peri-implant tissue compared to zinc oxide cements. In the present study 18 patients (8 males and 10 females) were examined with a split-mouth design. The follow-up period for patients after delivery of the cement-retained single crown is a maximum of 48 months. A total of 36 implants were inserted and monitored during this period. Clinical and radiographic tests were carried out on all 36 implants, with constant re-evaluation, as well as the occurrence of some prosthetic or biological problems that brought the patient back to visit. The results for both cements were in line with the indications of the respective manufacturers. During the observational period, no implant failed, with a survival rate of 100% on these 36 implants. In conclusion, it is possible to establish that the number of decementations of the cement-retained crowns cemented with Temp Bond non-eugenol was higher, but not statistically significant. In contrast, the biological complications per implant and the MBL were significantly higher in the cement-retained crowns cemented with Implacem

Identification, Evaluation and Utilization of Resistance to Insect Pests in Grain Legumes: Advancement and Restrictions

The 68th session of the UN General Assembly declared 2016 as the International Year of Pulses (IYP 2016), emphasizing the nutritional significance of legumes and their potential role for achieving global food security. Even though the IYP ended with enhanced public awareness about the nutritional aspects, other health benefits, and importance of mitigating climate change, and its role in promoting biodiversity, additional studies are required to increase the global production and trade of pulses. Major food legumes including chickpea, pigeonpea, cowpea, field pea, lentil, faba bean, black gram, green gram and Phaseolus beans play a vital role in food, nutritional security and sustainable crop production. Several insect pests damage grain legumes, of which Helicoverpa armigera; Maruca vitrata; Etiella zinckenella; Spodoptera litura and S. exigua; Melanagromyza obtusa; Ophiomyia phaseoli; Aphis craccivora and Bemisia tabaci; Empoasca spp., Megaleurothrips dorsalis and Caliothrips indicus; Mylabris spp.; and Callosobruchus chinensis cause extensive losses. Appreciable progress has been made in formulating screening techniques to evaluate germplasm, mapping populations and genetically modified crops for resistance to insect pests under field and greenhouse conditions. However, some of these techniques cannot be used for stem flies, pod fly, leafhoppers, thrips and aphids. There is a need to develop rearing protocols for such insects to undertake precise phenotyping studies. The indiscriminate use of insecticides has resulted in the development of insecticide resistance in pests. Identification and utilization of genetic sources of resistance is one of the eco-friendly approaches for the management of insect pests. There is a need to identify lines with diverse mechanisms of resistance and to develop insect resistant cultivars by diversifying the genetic variability utilizing the wild accessions of chickpea, pigeonpea and cowpea, which can be exploited for introgressions to enhance the levels of resistance to pod borers to build host plant resistance as an viable component of pest management in grain legumes for sustainable crop production

A comprehensive in vitro comparison of mechanical properties of two rotary endodontic instruments

Aim: The aim of the present study was to compare two different nickel–titanium (NiTi) rotary files, F-One Blue and F2 Protaper Gold (PTG), evaluating their properties such as cyclic fatigue resistance, torsional resistance, and bending properties. Materials and methods: Sixty F-One Blue (25.06) and 60 PTGF2 have been randomly divided into 3 groups of 20 instruments each. Each group was tested in a different way, in order to analyze three different properties: cyclic fatigue resistance, torsional resistance, and flexibility. Cyclic fatigue resistance was evaluated by inserting the instruments for 16 mm in a stainless-steel artificial canal with a 90° angle and 5 mm of curvature with recommended speed and torque. Time to fracture was recorded using a chronometer (1/100 seconds). The number of cycles to fracture (NCF) was then calculated. Fragments were collected, and their lengths were measured. Torsional resistance was evaluated on the apical 3 mm of each of the files to calculate torque to fracture (TtF) using an endodontic motor (KaVo, Biberach, Germany), which automatically recorded the torque values every 1/10 s. All instruments were rotated at the same speed (300 rpm) and torque value (5.5 Ncm). Flexibility was evaluated using a calibrated load cell supported by a computer program. All the collected data were statistically analyzed (t-test) with a significance level set at 5%. Results: A significant difference in terms of cyclic fatigue resistance, torsional resistance, and flexibility between F-One Blue and F2 PTG was found (p < 0.05). The mean value of NCF was 604.16 (SD ± 23.32) for F-One Blue and 300.5 (SD 19.92) for F2 PTG. The mean value of TtF was 1.41 Ncm (SD ± 0.01) and 1.39 Ncm (SD ± 0.01) for F2 PTG. The mean value of bending test was 29 gcm (SD ± 1.15) for F-One Blue and 50 gcm (SD ± 2.30) for F2 PTG. Conclusion: F-One Blue better resists to flexural and torsional stresses and seemed to be more flexible. Since F-One Blue mechanical tested performances were better than the F2 PTG ones, these instruments should be considered a very promising instrument. Clinical significance: As evidenced by the results of this study, F-One Blue should be considered a very promising instrument that could improve endodontic clinical practice

A survey on perceived COVID-19 risk in dentistry and the possible use of rapid tests

Aim: The present study was conducted to assess the perceived risk of COVID-19 transmission in dental professionals (DPs), that include dentists and dental auxiliary staffs, and whether rapid tests should be a recommended tool to constrain the transmission of the COVID-19, and who should be bearing their cost (governments, dentists, or patients) through an online survey. Materials and methods: A sample size of n = 700 was recruited in the study. The study included DPs from all over the world. A randomized selection of samples was done through dental groups present on social networks. An online survey was conducted in April 2020, using the Google Form software to provide questions and collect and elaborate answers. Data were analyzed using the statistical software STATA and presented in terms of percentages. Results: About 78% of the study participants perceived a very high risk of COVID-19 contamination in dental settings. Nearly 80% of the study participants were willing to be subjected to rapid tests and the same could be performed on patients visiting their dental clinics, which could prevent the spread of the disease. About 55% of the participants had reported that additional costs for the rapid tests should be borne by the governments. Conclusion: The results of the present survey report that DPs do not feel safe and perceive a high risk of COVID-19 contagion and prevention of the disease could be done by performing rapid tests on dentists, dental staff, and patients visiting the dental clinics irrespective of age and gender of the participants. Significance: Since all the dentists and allied staff have perceived increased risk for COVID-19 transmission, it is important that preventive measures are implemented through rapid test kits at the earliest

Fatigue resistance of two Nickel-Titanium rotary instruments before and after ex vivo root canal treatment

Aim: The aim of the present study is twofold: to evaluate cyclic fatigue resistance differences of two different nickel-titanium rotary instruments, brand new and after an ex vivo instrumentation of single root extracted teeth. Materials and methods: Twenty new S One 20.06 were randomly divided into two groups. The first group (n = 10) was immediately subjected to a cyclic fatigue test (S One Group I). The second group (n = 10) (S one Group II) performed a cyclic fatigue test after three ex vivo root canal treatment with a single-file technique. The same process has been carried out for 20 M-Two 20.06 instruments. Results: Mean time to fracture (TtF) for Group I was 51.14 ± 1.28 for S One and 32.62 ± 0.17 for M-Two 20.06 and for Group II was 46.00 ± 0.99 for S One and 27.75 ± 1.58 for M-Two 20.06. The reduction in TtF values from Group I to Group II was 11% for S One and 15% for M-Two. Statistical analysis found significant differences in all the groups examined (p value < 0.05). Mean fragment length (FL) for Group I was 3.07 ± 0.17 for S One and 3.05 ± 0.14 for M-Two 20.06 and for Group II was 3.05 ± 0.07 for S One and 3.05 ± 0.14 for M-Two 20.06. Statistical analysis was pursued, and no significant difference was found (p value > 0.05). Conclusion: The S-One showed significantly more resistance to cyclic fatigue stress than M-Two for both new and used instruments. This validates the hypothesis that the AF H wire enables the S One files to endure more the cyclic fatigue stresses. Clinical significance: This study demonstrates the cyclic fatigue resistance of a new endodontic instrument after repetitive usage

The influence of thermomechanical compaction on the marginal adaptation of 4 different hydraulic sealers: a comparative ex vivo study

Since there are no data in the literature regarding the comparison of the marginal adaptation of hydraulic sealers when used with a single-cone technique or through thermomechanical compaction, this study aimed to evaluate the behavior of four different endodontic sealers used with the two above-mentioned obturation techniques by evaluating the marginal gap existing between the obturation materials and the dentinal walls through scanning electron microscopy. Given this objective, a total of 104 single-rooted, straight canal teeth were selected and divided into four subgroups according to the selected endodontic sealer ((AH) Plus Bioceramic Sealer (AHP), EndoSequence BC Sealer HiFlow (ES), C-Root SP (CR), and GuttaFlow Bioseal (GF)). Each tooth was decoronated and instrumented with the HyFlex EDM/CM systematics up to 30.04. After irrigation procedures, the teeth of each subgroup were divided into two groups and obturated according to two different obturation techniques: the single-cone technique (SC) and the thermomechanical compaction technique (TC). After the required sealer setting time, each tooth was sectioned in three parts at 3, 6, and 9 mm from the apex, and each section was observed with a scanning electron microscope. The marginal gap of each sample was measured using G* Power Software v3.1, and the statistical analysis was performed using the Kruskal–Wallis test, followed by a post hoc Dunn’s test. Results showed that there were not any statistically significant differences in terms of the marginal gap between the two different above-mentioned obturation techniques for each sealer, except for the middle third of root canals, where a statistically significant difference was found for AHP, ES, and GF sealers. In conclusion, the thermomechanical compaction of hydraulic sealers and gutta-percha guarantees better sealing than the single-cone technique when the root canal shape is not rounded