Genes and single nucleotide polymorphisms in the pathway of saliva and dental caries: a systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to investigate the influence of single nucleotide polymorphisms (SNPs), related to genes in salivary composition and flow, on dental caries experience. Sixteen studies were included in the systematic review and ten in the meta-analysis. Forty-four SNPS, covering four genes (CA6, AQP2, AQP5, and MUC5B) were identified. Most of the SNPs were not associated with caries in meta-analysis. Homozygous TT genotype of the SNP CA6 rs17032907(C/T) was associated with caries [OR = 3.23(1.39-7.49)]. The pool effect of the SNPs assessed in AQP5 was associated with a reduction in the likelihood of caries [OR = 0.75(0.59-0.95)]. Considering all SNPs of salivary composition and flow, the effect allele was associated with a 75% increase in the likelihood of caries [OR = 1.75(1.06-2.89)] in the homozygous genotype. The present findings showed that the genes in salivary composition and flow can play an important role in dental caries experience.

Is the effect of COVID-19 on periodontal treatment similar to that in general dental care and primary medical care? an observational study in Brazil.

The present study aimed to analyze the effect of the COVID-19 pandemic on the rates of periodontal procedures, and provide a comparison with general dental care and primary medical care procedures carried out in the Brazilian Public Health System. The study had an ecological, retrospective design with data from 5,564 Brazilian municipalities (99.9%). A multilevel mixed-effects linear regression was used to analyze the longitudinal associations between the COVID-19 pandemic and the rate of procedures. There was a significant reduction in the number of periodontal procedures (Coef. -428.6 [95%CI -774.3/-82.9]) during the COVID-19 pandemic, although this reduction was no greater than that of medical and general dental procedures. Medical procedures witnessed the sharpest drop in procedures (Coef. -2831.5 [95%CI -3964.1/-1699.0]). A lower rate of general dental procedures was also identified during the pandemic (Coef. -2,110.6 [95%CI -3,400.8/-820.4]). The COVID-19 pandemic has had a negative effect on the rate of periodontal procedures carried out in the Brazilian Public Health System. The highest recutions were observed in general dental and medical procedures.

Comparison of endocrowns made of lithium disilicate glass-ceramic or polymer-infiltrated ceramic networks and direct composite resin restorations: fatigue performance and stress distribution.

This study compared the fatigue performance and the stress distribution of endodontically treated molars restored with endocrowns obtained with lithium disilicate glass-ceramic or a polymer-infiltrated ceramic network, both processed by CAD-CAM, and direct composite restorations. Forty-eight human mandibular molars were randomly assigned into 03 groups (n = 16) and restored with endocrowns (LD - lithium disilicate glass-ceramic or PICN - polymer-infiltrated ceramic network) or with direct composite restorations. Fatigue testing followed a step-stress approach (initial maximum load of 200 N and 5000 cycles, incremental step load of 200N and 10,000 cycles/step, being the specimens loaded until failure or to a maximum of 135,000 cycles at 2800 N). The fatigue failure load and number of cycles until failure were recorded and statistically analyzed. Fractographic and finite element (FEA) analyzes were conducted as well. There were no differences in fatigue failure load, number of cycles until fracture and mean survival probabilities among groups. However, indirect endocrowns had higher mechanical structural reliability, and LD restorations lasted more time before start to failing. FEA showed that the stress concentration in tooth tissues was higher for the resin composite, followed by PICN and LD in a decreasing order. Almost all fractures were restricted to the restorative material (without tooth involvement), and origins were identified at occlusal surface. The type of restoration did not influence the fatigue failure load, number of cycles until fracture and mean survival probabilities of the restorative strategies. Despite that, the mechanical structural reliability of endocrowns, especially those made of lithium disilicate, was higher and lasted more time before start to failing.