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Purpose: To investigate the possible antimicrobial activity of glycine air polishing by comparing peri-implant microbiota before and after treatment. Materials and Methods: A total of 15 patients who received implant-supported full-arch fixed rehabilitations were included. After prosthesis removal (T0), Plaque Index (PI), probing depth (PD), and bleeding on probing (BOP) were recorded. In each hemiarch, the implant with the highest PD score was selected for microbiologic sample collection from the peri-implant sulcus (T0). All patients received two different hygienic protocols (randomly administered, one per each hemiarch): glycine air-polishing (G) and cleansing with cotton pellets soaked in saline (C). At 7 days (T1) and 3 months (T2) after the intervention, PI and BOP were recorded, and new microbiologic samples were taken. Traditional polymerase chain reaction (PCR) and quantitative PCR real-time were employed for microbiologic analysis to investigate how the presence of different bacterial species varied according to the hygienic treatment performed. Results: Treatment G provided a significantly higher PI score reduction around implants compared to treatment C (P = .015). No statistical difference was found in the microbial population around G and C implant sites, with Tannerella forsythia being the most commonly detected bacterial species in both G and C groups. No statistical differences were found between the antimicrobial activity of treatments C and G. Conclusions: Glycine powder air polishing is a valid method for professional hygienic care of implants and was more effective in PI reduction compared to the control treatment. However, its antimicrobial efficacy cannot be confirmed by the outcomes of the present study. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this clinical study is to compare implant full-arch intraoral scans taken immediately after implant placement with those obtained after tissue healing in patients rehabilitated with implant-supported fixed prostheses. Methods: Between September 2023 and March 2024, a total of 19 patients with compromised residual dentition (6 women; 13 men) were rehabilitated using 4-to-6 immediately loaded post-extraction implants. These implants supported fixed full-arch screw-retained prostheses either in the lower jaw (9 patients) or upper jaw (10 patients). Intraoral scans were taken immediately after implant placement (termed "immediate scan"). After a healing period of four months, the provisional prosthesis was removed, and a second intraoral scan was performed using the same scan bodies and scan pattern as the initial scan (termed "delayed scan"). The two scans were overlaid, and the discrepancies between them were measured. Results: The average discrepancy between the immediate and delayed scans was 0.1905 mm. Our statistical analysis revealed larger discrepancies for implants placed in the posterior areas, with the implant in site 1.6 (Implant 1) showing a discrepancy of 0.2326 mm, and the implant in site 2.6 (Implant 4) showing a discrepancy of 0.2124 mm (p = 0.05). No statistically significant difference was observed when comparing patients treated in the upper and lower jaws. Conclusions: Within the limitations of the study and based on this result, clinicians should be aware that an immediate post-surgical intraoral digital scan for implant-supported full-arch rehabilitations may result in a higher risk of imprecision. Furthermore, according to the results of the study, the accuracy of the digital impression on implant full-arch rehabilitations seems to be influenced by the clinician's skills. Further studies with larger sample sizes are required to confirm our results. [ABSTRACT FROM AUTHOR]

Background: Restorative materials might significantly affect load transmission in peri-implant bone. The aim of the present study is to evaluate the shock absorption capacity of two different polymeric materials to be used for implant-supported prostheses. Methods: A masticatory robot was used to compare the shock absorption capacity of veneered and non-veneered polyetherketoneketone (PEKK), Pekkton®ivory (Cendres+Mètaux), and the glass fiber-reinforced composite (GFRC), TRINIATM (Bicon). Five identical sample crowns for each of the three groups were tested. Forces transmitted at the simulated peri-implant bone were recorded and statistically analyzed. Results: The statistical analysis of forces transmitted at the simulated dental implant revealed significant differences between the materials tested and between these materials and zirconia, glass ceramic, composite resin, and acrylic resin. Only differences between PEKK and veneered PEKK and between PEKK and one of the previously tested composite resins were not statistically significant. PEKK samples demonstrated significantly greater shock absorption capacity compared to GFRC. Conclusions: PEKK revealed optimal shock absorption capacity. Further studies are needed to evaluate its efficacy in the case of long-span prostheses with reduced prosthetic volume. [ABSTRACT FROM AUTHOR]

In a rat model of long-lasting pressure-overload hypertrophy, we investigated whether changes in the relative expression of myocardial actin isoforms are among the early signs of ventricular mechanical dysfunction before the transition toward decompensation. Forty-four rats with infrarenal aortic banding (AC rats) were studied. Hemodynamic parameters were measured 1 mo (A[C.sub.1] group; n = 20) or 2 mo (A[C.sub.2]; n = 24) after aortic ligature. Then subgroups of A[C.sub.i] and A[C.sub.2] left ventricles (LV) were used to evaluate 1) LV anatomy and fibrosis (morphometry), 2) expression levels (immunoblotting) and spatial distribution (immunohistochemistry) of alpha-skeletal actin ([alpha]-SKA), alpha-cardiac actin ([alpha]-CA), and alpha-smooth muscle actin ([alpha]-SMA), and 3) cell mechanics and calcium transients in enzimatically isolated myocytes. Although the two AC groups exhibited a comparable degree of hypertrophy (+30% in LV mass; +20% in myocyte surface) and a similar increase in the amount of fibrosis compared with control animals (C group; n = 22), a worsening of LV mechanical performance was observed only in A[C.sub.2] rats at both organ and cellular levels. Conversely, A[C.sub.1] rats exhibited enhanced LV contractility and preserved cellular contractile behavior associated with increased calcium transients. Alpha-SKA expression was upregulated (+60%) in A[C.sub.1]. In A[C.sub.2] ventricles, prolonged hypertension also induced a significant increase in [alpha]-SMA expression, mainly at the level of arterial vessels. No significant differences among groups were observed in [alpha]-CA expression. Our findings suggest that [alpha]-SKA expression regulation and wall remodeling of coronary arterioles participate in the development of impaired kinetics of contraction and relaxation in prolonged hypertension before the occurrence of marked histopathologic changes. aortic ligature; hypertension

The serine-threonine kinases Pim-1 and Akt regulate cellular proliferation and survival. Although Akt is known to be a crucial signaling protein in the myocardium, the role of Pim-1 has been overlooked. Pim-1 expression in the myocardium of mice decreased during postnatal development, re-emerged after acute pathological injury in mice and was increased in failing hearts of both mice and humans. Cardioprotective stimuli associated with Akt activation induced Pim-1 expression, but compensatory increases in Akt abundance and phosphorylation after pathological injury by infarction or pressure overload did not protect the myocardium in Pim-1-deficient mice. Transgenic expression of Pim-1 in the myocardium protected mice from infarction injury, and Pim-1 expression inhibited cardiomyocyte apoptosis with concomitant increases in Bcl-2 and Bcl-X[sub.L] protein levels, as well as in Bad phosphorylation levels. Relative to nontransgenic controls, calcium dynamics were significantly enhanced in Pim-1-overexpressing transgenic hearts, associated with increased expression of SERCA2a, and were depressed in Pim-1-deficient hearts. Collectively, these data suggest that Pim-1 is a crucial facet of cardioprotection downstream of Akt., Author(s): John A Muraski [1]; Marcello Rota [2]; Yu Misao [2]; Jenna Fransioli [1]; Christopher Cottage [1]; Natalie Gude [1]; Grazia Esposito [2]; Francesca Delucchi [2]; Michael Arcarese [2]; Roberto [...]

In a rat model of diabetic cardiomyopathy, we tested whether specific changes in myocyte turnover and intercellular coupling contribute to preserving ventricular performance after a short period of hyperglycemia. In 41 rats with streptozotocin-induced diabetes and 24 control animals, cardiac electromechanical properties were assessed by telemetry ECG, epicardial potential mapping, and hemodynamic measurements to document normal ventricular function. Myocardial remodeling, expression of gap-junction proteins and myocyte regeneration were evaluated by tissue morphometry, immunohistochemistry and immunoblotting. Ventricular myocyte number and volume were also determined. In diabetic hearts, after 3 weeks of hyperglycemia, left ventricular mass was lowered by 23%, while left ventricular wall thickness and chamber volume were maintained, in the absence of fibrosis and myocyte hypertrophy. In the presence of a marked DNA oxidative damage, an increased rate of DNA replication and mitotic divisions associated with generation of new myocytes were detected. The number of cells expressing the receptor for Stem Cell Factor (c-kit) and their rate of proliferation were preserved in the left ventricle while the atrial storage of these primitive cells was severely reduced by diabetes-induced oxidative stress. Despite a down-regulation of Connexin43 and over-expression of both Connexin40 and Connexin45, the junctional proteins were normally distributed in diabetic ventricular myocardium,justifying the preserved tissue excitability and conduction velocity. In conclusion, before the appearance of the diabetic cardiomyopathic phenotype,myocardial cell proliferation associated with gap junction protein remodeling may contribute to prevent marked alterations of cardiac structure and electrophysiological properties, preserving ventricular performance. [ABSTRACT FROM AUTHOR]

A correction to the article "Pim-1 regulates cardiomyocyte survival downstream of Akt," by John A. Muraski and colleagues, is presented.