Oral commensal bacterial flora is responsible for peripheral differentiation of neutrophils in the oral mucosa in the steady state.

OBJECTIVES: Commensal bacteria in the host body play a fundamental role in the differentiation and maintenance of the immune system. Studies on intestinal immunity have revealed that, under steady-state conditions, microflora have an important role in the maintenance of health. However, the role of oral commensal bacteria on the oral immune system is still unclear. Here, we clarify the interactions between commensal bacteria and the oral mucosal immune system under steady-state conditions. METHODS: We used germ-free mice that had never been exposed to bacteria and conventional mice grown with normal bacterial flora. Oral cells were isolated from the oral mucosa, stained with specific antibodies, and analyzed by flow cytometry. For the detection of myeloperoxidase and intracellular cytokines, oral cells were stimulated with N-formyl-methionine-leucyl-phenylalanine and phorbol 12-myristate 13-acetate/ionomycin, respectively. RESULTS: We found that the oral mucosa harbored more neutrophils in germ-free mice than in conventional mice. However, the majority of neutrophils in the germ-free oral mucosa exhibited an immature phenotype. Other immune cells, including macrophages, T cells, and B cells, in the oral mucosa of germ-free mice showed similar differentiation to those in conventional mice. These results indicate that in the steady-state oral mucosa, the normal commensal flora promote the peripheral differentiation of neutrophils. CONCLUSIONS: The presence of commensal flora is critical for the development of adequate immune system in the oral mucosa.

Impact of the COVID-19 Pandemic on Paediatric Dental Treatment: A Retrospective Study in Banja Luka, Bosnia and Herzegovina.

Dentists are at significant risk of COVID-19 infection. It was difficult to find a balance between dental care, especially preventive and other non-urgent dental procedures, and prevention of potential exposure to SARS-CoV-2 infection. The aim of the present study was to assess the influence of the COVID-19 pandemic on dental treatment in children in the Dental Clinic of the University of Banja Luka, and to compare it before and during the first and second years of the pandemic. All dental records of paediatric patients who attended the Dental Clinic (for the period March 2019 to March 2022) were analysed. The data on selected dental treatment procedures were divided into three groups per year and compared. The results during the first year of the COVID-19 pandemic showed a reduction in single treatments compared to the year before, while in the second year there was an increase in some interventions such as oral hygiene training and patient motivation, deciduous tooth extraction, and glass ionomer filling. Although the number of dental treatments in the clinic in the second year nearly returned to pre-pandemic levels, preventive and restorative interventions are the most appropriate strategy to improve the oral health of children after the COVID-19 pandemic.

Melatonin suppresses the antiviral immune response to EMCV infection through intracellular ATP deprivation caused by mitochondrial fragmentation.

Melatonin, a sleep hormone derived from the pineal gland, has an anti-inflammatory effect on the immune system in addition to modulating the brain nervous system. Previous studies have shown that melatonin suppresses signaling pathways downstream of multiple pattern recognition receptors on the innate immune cells during pathogen infection, but the specific mechanism of suppression has not been well understood. Using an encephalomyocarditis virus (EMCV) infection model in macrophages, we investigated the effects of melatonin on the antiviral response in innate immunity and found that melatonin attenuated the uptake of viral particles into macrophages. Furthermore, melatonin suppressed cytoskeletal regulation by decreasing ATP production by mitochondria. Finally, in an in vivo infection experiment, we also found that melatonin administration partially exacerbated the infection in the mouse brain. These results suggest that melatonin may have an inhibitory effect on excessive inflammation by suppressing cytoskeletal regulation in the innate immune system, but also suggest that suppression of inflammation may lead to insufficient protection against EMCV infection in vivo.

Application of Semipermanent Cements and Conventional Cement with Modified Cementing Technique in Dental Implantology.

OBJECTIVES: The aim of this study was to evaluate the influence of artificial ageing on the retention force of original semipermanent cements, as well as the possibility of using conventional cements for semipermanent cementation with adequate modification of the cementing protocol. MATERIALS AND METHODS: Forty CoCrMo alloy crowns were divided in four groups (each group n=10) and fixed with two semipermanent cements (resin-based and glass ionomer-based cements) and one conventional (zinc phosphate), using conventional and modified cementation techniques on titanium abutments. The samples were stored in humid conditions for 24 hours at 37°C and subjected to thermocycling (500 cycles) and mechanical cyclic loading (7 days, 3, 6, 9 and 12 months function simulation). The cast crowns were removed and the retention force was recorded. RESULTS: The highest initial retention force measured was for zinc-phosphate cement - conventional cementing (198,00±61,90 N), followed in descending order by zinc-phosphate cement - modified cementing technique (152,00±45,42 N), long term temporary cement - GC Fuji Temp LT (57,70±20,40 N), and semipermanent cement - Telio CS Cem Implant (56,10±18,68 N). After 12 months, the highest retention force measured was for zinc-phosphate cement - conventional cementing (88, 90±14, 45 N), followed by zinc-phosphate cement - modified cementing (48, 15±14,41N), semipermanent cement GC Fuji Temp LT (16,55±3,88 N) and Telio CS Cem Implant (15,55±5,52 N). CONCLUSIONS: Zinc-phosphate cement - modified cementing technique and original semipermanent cements can be recommended for conditional permanent cementing of implant supported crowns. CLINICAL RELEVANCE: The use of semipermanenet cements and zinc-phosphate cement - modified cementing technique provides a predictable retrievability of implant-supported crowns.

Validation of Cariogram in Caries Prediction in Women and Their Children 4 Years After Pregnancy - Longitudinal Study.

BACKGROUND: Cariogram®, an algorithm-based software model, for predicting caries risk has been used to assess the caries risk profile of many different groups. The aims of the study were to evaluate Cariogram caries risk assessment during pregnancy with DMFT/dmft incidence in mothers and their children 4 years after pregnancy and to check if there is an association between children's caries risk profiles using Cariogram and caries risk profiles (by Cariogram) of their mothers during pregnancy. METHODS: The study population consisted of 96 pregnant women (average age 27.4±7.2 years at baseline) who completed clinical baseline examination and salivary tests. The follow-up study was initiated 4 years later and the 80 pairs of mother and children (from that pregnancy) were re-examined using the same procedure at baseline. An individual caries risk profile and DMFT/dmft incidence were made for each woman and child. The prediction of the Cariogram was compared to the actual dental experience in 4 years. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for two cut-offs were calculated to express the outcome. RESULTS: The results showed a strong association between the risk categories of pregnant women and their offspring as well as between caries development in offspring and the Cariogram risk categories of pregnant women. Sensitivity and PPV for new DMFT (ΔDMFT>0) 4 years after for women were  high (>80%) for those participants assessed with 0-60% "chance to avoid caries", as well as diagnostic accuracy (74.00%). High specificity (91.00%), very high PPV (95.00%) and clinically useful values according to Youden's index (0.53) were obtained for moderate-risk and two lowest-risk groups for dmft in children. CONCLUSION: Cariogram was valid in the authors' sample only and highly predictive in caries risk assessment in investigated children based on caries risk assessment of their mothers in pregnancy.

The Effect of Long-Term Antihypertensive Therapy on the Change in Secretion and Calcium, Bicarbonate and Phosphate Ion Concentration in Non-Stimulated and Stimulated Saliva.

OBJECTIVE: The aim of this study was to evaluate the amount of saliva secreted and calcium, bicarbonate, and phosphate ion concentration in patients receiving antihypertensive for five years or over five years (patient group) and in healthy patients (control group). MATERIAL AND METHODS: The patient or experimental group included 31 subjects who were admitted to a cardiovascular clinic and had been receiving an antihypertensive drug therapy for more than five years. The control group included 31 healthy subjects. The measured amount of saliva was further used to determine the calcium, phosphate and bicarbonate ion concentration values. Calcium and phosphate ions were determined spectrophotometrically, while bicarbonate ions were determined by titration. RESULTS: A two-way-test (Student's test) was used to compare the values of variables. The amount of excreted saliva was statistically significantly lower in the patient group in non-stimulated (1.739 mL/5 min) and stimulated saliva (3.594 mL/5 min). Calcium ion concentration was statistically significantly lower in patient group in resting saliva (6.143 mg/dL). Bicarbonate and phosphate ion concentration in patient group was statistically significantly higher in non-stimulated (bicarbonate ion = 14.041 mmol/L, phosphate ion = 2.818 µmol/L) and stimulated saliva (bicarbonate ion = 10.872 mmol/L, phosphate ion = 1.454 µmol/L), respectively. CONCLUSION: A reduced amount of saliva and calcium ion concentration indicates the possibility of a higher frequency of hard dental tissue demineralization process. On the contrary, the increase in the phosphate and bicarbonate ion concentration in the patient group affects the regulation of acid-base balance, thus having a preventive effect.