Effect of Polishing Systems on the Surface Roughness of Nano-Hybrid and Nano-Filling Composite Resins: A Systematic Review.

BACKGROUND: The polishing of surface roughness is an important characteristic of composite resins and is directly related to the longevity of the restoration and patient comfort. Different polishing systems utilize different protocols, as reported in the literature. This systematic review (SR) aimed to synthesize and analyze the available scientific evidence about the effect of polishing systems on the surface roughness of nano-hybrid and nano-filling composite resins. METHODS: The study protocol of this SR was registered at the International Prospective Register of Systematic Reviews -PROSPERO- (CRD4201705653). A search was conducted in PubMed-Medline, Scopus, LILACS, EMBASE, for the period 2007-2020. Quality appraisal and a descriptive analysis of the papers that met the inclusion criteria were conducted. RESULTS: 18 records were included. Seven polishing systems (PS) of one step were found, seven PS of two steps, eight PS of three steps, three PS of four steps, and four PS of five steps. Polishing protocols (PP) varied, with application times ranging from 10 s to 60 s with speeds between 10,000 and 30,000 RPM. Regarding composition, the aluminum oxide was one of the most important components used to achieve a smooth surface. CONCLUSIONS: Multistep polishing systems were the most effective (i.e., Astropol and Sof-Lex Discs).

CKM gene polymorphism in Russian and Polish rowers.

Muscle-specific creatine kinase (CKMM) plays a vital role in the energy homeostasis of muscle cells. The A/G variation (rs8111989) located in the 3'-untranslated region of the CKM gene has been found to be the most relevant in terms of genetic testing in sport. The aim of the presented study was to test the hypothesis that the G allele might represent a genetic element that contributes to the improvement of endurance performance in Polish and Russian rowers. The distribution of the CKM genotypes was examined in a group of Polish and Russian athletes in comparison with non-athlete controls. There were no statistical differences between the rowers and the control groups across the CKM genotypes when Polish or Russian participants were analyzed. Based on the obtained results, it may be speculated that the CKM A/G polymorphism is not an important determinant of endurance performance level in Polish and Russian rowers. However, these results should be interpreted with caution as they can be limited by many factors.

Association of the 174 G/C polymorphism of the IL6 gene in Polish power-orientated athletes.

AIM: Interleukin-6 (IL6), has been called by some authors "an exercise factor" due to its pleiotropic effects during physical training. Several studies indicated that change in the guanine bases to cytosine at position -174 affects the transcription of the IL6 gene, and finally IL6 production level. The aim of this study was to perform confirmation studies to analyze the possible importance of the IL6 -174 G/C (rs1800795) polymorphism gene in Polish power-orientated athletes. METHODS: The study was carried out on two groups of men of the same Caucasian descent: 158 power-orientated athletes and 254 volunteers not involved in competitive sport. DNA was extracted from buccal cells donated by the subjects. Genotyping was carried out by polymerase chain reaction (PCR). Significance was assessed by Chi square (χ2) analysis. RESULTS: The results revealed that the frequency of the IL6 -174 GG genotype (53.16% vs. 35.82%; P=0.002) and G allele (68.67% vs. 57.87%; P=0.03) were significantly higher in the Polish power-orientated athletes compared to controls. CONCLUSION: These data suggest that the G allele could be one of the factors influencing the power-orientated sport performance. However, these conclusions should be supported with more experimental studies on other IL6 polymorphisms and other genes.

The +1245g/t polymorphisms in the collagen type I alpha 1 (col1a1) gene in polish skiers with anterior cruciate ligament injury.

OBJECTIVES: The aim of this study was to examine the association of +1245G/T polymorphisms in the COL1A1 gene with ACL ruptures in Polish male recreational skiers in a case-control study. METHODS: A total of 138 male recreational skiers with surgically diagnosed primary ACL ruptures, all of whom qualified for ligament reconstruction, were recruited for this study. The control group comprised 183 apparently healthy male skiers with a comparable level of exposure to ACL injury, none of whom had any self-reported history of ligament or tendon injury. DNA samples extracted from the oral epithelial cells were genotyped for the +1245G/T polymorphisms using real-time PCR method. RESULTS: Genotype distributions among cases and controls conformed to Hardy-Weinberg equilibrium (p = 0.2469 and p = 0.33, respectively). There was a significant difference in the genotype distribution between skiers and controls (p = 0.045, Fisher's exact test). There was no statistical difference in allele distribution: OR 1.43 (0.91-2.25), p = 0.101 (two-sided Fisher's exact test). CONCLUSIONS: The risk of ACL ruptures was around 1.43 times lower in carriers of a minor allele G as compared to carriers of the allele T.

Dual guidance improves needle tip placement for peripheral nerve blocks in a porcine model.

BACKGROUND: The objective of the study was to evaluate whether the use of ultrasound (US) together with nerve stimulation (USNST) provides a better needle tip position for performing peripheral regional anaesthesia than the use of US or nerve stimulation (NST) alone. METHODS: Needle placements were applied at the brachial plexus and sciatic nerves in 32 anaesthetised pigs. Following needle placement near the target nerve, using either the USNST or the US or NST, a volume of 0.3 ml synthetic resin was injected mimicking a 'test-dose' injection. The primary outcome was the incidence of close needle-to-nerve placement assessed by injectate localisation in direct contact with the nerve epineurium. Secondary endpoints were the incidences of intraneural injection and haematoma formation in direct contact with the target nerve. RESULTS: A total of 611 punctures were performed. The evaluation for the criterion 'close needle placement' revealed significant differences in favour of the USNST group (98.5%) compared with the NST (90.1%) and the US group (81.6%) (P = 0.001). Significant differences were observed regarding 'intraneural needle placement' between the groups as well (USNST, 0.5%; US, 4%; NST, 2.5%; P = 0.034). The incidence of haematoma formation was significantly higher in the NST group (10.8%) than in the US group (2.5%) and in the USNST group (1.5%) (P = 0.001). CONCLUSION: These findings suggest that the USNST approach combines the benefits of the US and the NST techniques in terms of a higher rate of close needle tip placements and a lower incidence of haematoma formation.

The GABPB1 gene A/G polymorphism in Polish rowers.

Nuclear respiratory factor 2 (NRF2), also referred to as the GA-binding protein (GABP) transcription factor, is a key transcriptional activator of many nuclear genes which encode a wide range of mitochondrial enzymes. The variants of the GABPB1 gene encoding the beta1 subunit of NRF2 protein have been associated with physical performance, particularly endurance. The aim of this study was to confirm the possible importance of the A/G polymorphism (rs7181866) in intron 3 of the GABPB1 gene in Polish rowers. The study was carried out on 55 Polish rowers and sedentary individuals, to evaluate the possible relationships between genotype and physical performance. DNA was extracted from buccal cells donated by the subjects. Genotyping was carried out by PCR-RFLP. The results revealed that the frequency of the GABPB1 A/G genotype (89.09% AA; 10.91% AG, 0% GG; vs. 97.69% AA; 2.31% AG; 0.00% GG) %; P = 0.012) and G allele (5.50% vs. 1.17%; P = 0.014) was significantly higher in the rowers compared to controls. The results suggest that the GABPB1 gene can be taken into consideration as a genetic marker in endurance athletes. However, these conclusions should be supported with more experimental studies on other GABPB1 polymorphisms and other genes in elite endurance athletes.

Is the C34T polymorphism of the AMPD1 gene associated with athlete performance in rowing?

The skeletal muscle-specific isoform of adenosine monophosphate deaminase (AMPD) is one of the most important regulators of muscle energy metabolism. A nonsense C to T transition in nucleotide 34 (C34T) in exon 2 of AMPD1 gene converts the codon CAA into the premature stop-codon TAA. 127 Polish male rowers including Olympic and world champions were recruited for this study. Controls samples were obtained from 251 unrelated volunteers. Statistically significant differences in genotype distribution were observed when only a whole group of rowers (88.19% CC, 11.81% CT, 0% TT; p=0.009) were compared with controls (75.31% CC, 23.10% CT, 1,59% TT). A significant deficiency of the T allele compared to control samples was noted in the elite rowers (4.55%, p=0.021) and non-elite rowers (6.63%, p=0.023), whereas this trend was even stronger when compared with the controls for the whole group of rowers (5.91%, p=0.002). Our results suggest that the T allele is associated with physical performance level, therefore, it may be included in the group of performance altering polymorphisms as a negative factor to athletic performance.