Micro-computed tomography for assessing the internal and external voids of bulk-fill composite restorations: A technical report

none6noopenTosco, Vincenzo; Monterubbianesi, Riccardo; Furlani, Michele; Giuliani, Alessandra; Putignano, Angelo; Orsini, GiovannaTosco, Vincenzo; Monterubbianesi, Riccardo; Furlani, Michele; Giuliani, Alessandra; Putignano, Angelo; Orsini, Giovann

The symmetric 3D organization of connective tissue around implant abutment: a key-issue to prevent bone resorption

Symmetric and well-organized connective tissues around the longitudinal implant axis were hypothesized to decrease early bone resorption by reducing inflammatory cell infiltration. Previous studies that referred to the connective tissue around implant and abutments were based on two-dimensional investigations; however, only advanced three-dimensional characterizations could evidence the organization of connective tissue microarchitecture in the attempt of finding new strategies to reduce inflammatory cell infiltration. We retrieved three implants with a cone morse implant–abutment connection from patients; they were investigated by high-resolution X-ray phase-contrast microtomography, cross-linking the obtained information with histologic results. We observed transverse and longitudinal orientated collagen bundles intertwining with each other. In the longitudinal planes, it was observed that the closer the fiber bundles were to the implant, the more symmetric and regular their course was. The transverse bundles of collagen fibers were observed as semicircular, intersecting in the lamina propria of the mucosa and ending in the oral epithelium. No collagen fibers were found radial to the implant surface. This intertwining three-dimensional pattern seems to favor the stabilization of the soft tissues around the implants, preventing inflammatory cell apical migration and, consequently, preventing bone resorption and implant failure. This fact, according to the authors’ best knowledge, has never been reported in the literature and might be due to the physical forces acting on fibroblasts and on the collagen produced by the fibroblasts themselves, in areas close to the implant and to the symmetric geometry of the implant itself

Microleakage Analysis of Different Bulk-Filling Techniques for Class II Restorations: µ-CT, SEM and EDS Evaluations

none8This study aimed to compare two different bulk-filling techniques, evaluating the internal and external adaptation of class II resin-composite restorations, by analysing the gap formation using microcomputed tomography (µ-CT) and scanning electronic microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Two standardized mesio/disto-occlusal (MO/DO) cavities were prepared in eight extracted human third molars that were divided, according to the filling technique used, in the following two groups (n = 4): BG (Bulk&Go group) and BT (Bulk Traditional group). After universal bonding application, followed by the light curing, all teeth were restored using a bulk-fill composite. Specimens were scanned with µ-CT to evaluate 3D interfacial gaps. Acquired µ-CT data were analysed to quantify the gap formation. Complementary information to the µ-CT analysis were obtained by SEM. Thereafter, the chemical composition of tooth-restoration interface was analysed using EDS. The µ-CT analysis revealed gaps formation at the tooth-restoration interface for both the BG and BT groups, while within the restoration, only in the BT group there was evidence of microleakage formation. The scanning electron micrographs of both groups showed that the external marginal integrity of the restoration was preserved, while EDS showed the three different structures (tooth surface, adhesive layer and resin composite) of the tooth-restoration interface, highlighting the absence of gap formation. In both BG and BT, the two filling techniques did not show significant differences regarding the internal and external marginal adaptation of the restoration. To achieve a successful restoration, the clinician could be advised to restore a class II cavity using a single increment bulk-filling technique (BG), thus treating it as a class I cavity.openTosco, Vincenzo; Vitiello, Flavia; Furlani, Michele; Gatto, Maria Laura; Monterubbianesi, Riccardo; Giuliani, Alessandra; Orsini, Giovanna; Putignano, AngeloTosco, Vincenzo; Vitiello, Flavia; Furlani, Michele; Gatto, Maria Laura; Monterubbianesi, Riccardo; Giuliani, Alessandra; Orsini, Giovanna; Putignano, Angel

Biphasic calcium phosphate biomaterials: Stem Cell-derived Osteoinduction or In-vivo Osteoconduction? Novel insights in Maxillary Sinus Augmentation by advanced Imaging

none11noMaxillary sinus augmentation is often necessary prior to implantology procedure, in particular in cases of atrophic posterior maxilla. In this context, bone substitute biomaterials made of biphasic calcium phosphates, produced by three-dimensional additive manufacturing were shown to be highly biocompatible with an efficient osteoconductivity, especially when combined with cell-based tissue engineering. Thus, in the present research, osteoinduction and osteoconduction properties of biphasic calcium-phosphate constructs made by direct rapid prototyping and engineered with ovine-derived amniotic epithelial cells or amniotic fluid cells were evaluated. More in details, this preclinical study was performed using adult sheep targeted to receive scaffold alone (CTR), oAFSMC, or oAEC engineered constructs. The grafted sinuses were explanted at 90 days and a cross-linked experimental approach based on Synchrotron Radiation microCT and histology analysis was performed on the complete set of samples. The study, performed taking into account the distance from native surrounding bone, demonstrated that no significant differences occurred in bone regeneration between oAEC-, oAFMSC-cultured, and Ctr samples and that there was a predominant action of the osteoconduction versus the stem cells osteo-induction. Indeed, it was proven that the newly formed bone amount and distribution decreased from the side of contact scaffold/native bone toward the bulk of the scaffold itself, with almost constant values of morphometric descriptors in volumes more than 1 mm from the border.openGiovanna Iezzi, Antonio Scarano, Luca Valbonetti, Serena Mazzoni, Michele Furlani, Carlo Mangano, Aurelio Muttini, Mario Raspanti, Barbara Barboni, Adriano Piattelli, Alessandra GiulianiIezzi, Giovanna; Scarano, Antonio; Valbonetti, Luca; Mazzoni, Serena; Furlani, Michele; Mangano, Carlo; Muttini, Aurelio; Raspanti, Mario; Barboni, Barbara; Piattelli, Adriano; Giuliani, Alessandr

Multidisciplinary evaluation of the remineralization potential of three fluoride-based toothpastes on natural white spot lesions.

OBJECTIVES This in vitro study aimed assessing the remineralization potential of three commercial fluoride-based toothpastes in permanent teeth with natural white spot lesions (WSLs). A multidisciplinary approach based on Raman microspectroscopy (RMS), Scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS), and Vickers microhardness (VMH) was exploited. METHODS N = 12 human molars with natural WSLs in the proximal-vestibular zone were selected and divided into 4 groups (n = 3) according to the different treatments: HAF (hydroxyapatite with fluoride ions); SMF (sodium monofluorophosphate with arginine); SF (sodium fluoride with enzymes), and CTRL (untreated group). All toothpastes tested contained 1450 ppm of fluoride. Teeth samples were submitted to the following protocol: a 7-day pH cycling treatment, with two daily exposures (2 min each time) to the commercial toothpastes described above. The surface micromorphology (SEM), the chemical/elemental composition (RMS and EDS), and the Vickers microhardness (VMH) were evaluated. Statistical analysis was performed. RESULTS A remarkable remineralization of WSLs in SEM images was observed in all treated groups compared to CTRL. In particular, HAF and SF displayed higher values of VMH, phosphates amount (I960), crystallinity (FWHM960), and lower ones of C/P (I1070/I960) with respect to CTRL. Intermediate values were found in SMF, higher than CTRL but lower with respect to HAF and SF. As regards the Ca/P ratio, statistically significant differences (p < 0.05) were found between SF and the other groups. CONCLUSIONS All the tested dentifrices have shown to remineralize the WSLs. SF and HAF have comparable capability in hardness recovery and crystallinity; however, SF shows the best remineralizing potential according to both micromorphological and chemical analyses. Clinical relevance The daily use of toothpastes containing hydroxyapatite partially replaced with fluoride, sodium monofluorophosphate with arginine and sodium fluoride toothpaste associated with enzymes represents a preventive, therapeutic, effective, and non-invasive tool for remineralize WSLs

Psychological impact of Covid-19 pandemic on oncological patients: a survey in Northern Italy

The psychological impact of the Covid 19 pandemic on cancer patients, a population at higher risk of fatal consequences if infected, has been only rarely evaluated. This study was conducted at the Departments of Oncology of four hospitals located in the Verona area in Italy to investigate the psychological consequences of the pandemic on cancer patients under active anticancer treatments. A 13-item ad hoc questionnaire to evaluate the psychological status of patients before and during the pandemic was administered to 474 consecutive subjects in the time frame between April 27th and June 7th 2020. Among the 13 questions, 7 were considered appropriate to elaborate an Emotional Vulnerability Index (EVI) that allows to separate the population in two groups (low versus high emotional vulnerability) according to observed median values. During the emergency period, the feeling of high vulnerability was found in 246 patients (53%) and was significantly associated with the following clinical variables: female gender, being under chemotherapy treatment, age 64 65 years. Compared to the pre-pandemic phase, the feeling of vulnerability was increased in 41 patients (9%), remained stably high in 196 (42%) and, surprisingly, was reduced in 10 patients (2%). Overall, in a population characterized by an high level of emotional vulnerability the pandemic had a marginal impact and only a small proportion of patients reported an increase of their emotional vulnerability

Notulae to the Italian alien vascular flora: 11

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1

Unraveling the biomechanical properties of collagenous tissues pathologies using synchrotron-based phase-contrast microtomography with deep learning

Mechanical stimuli are regulators not only in cells but also of the extracellular matrix activity, with special reference to collagen bundles composition, amount and distribution. Synchrotron-based phase-contrast computed tomography was widely demonstrated to resolve collagen bundles in 3D in several body districts and in both pre-clinical and clinical contexts. In this perspective study we hypothesized, supporting the rationale with synchrotron imaging experimental examples, that deep learning semantic image segmentation can better identify and classify collagen bundles compared to common thresholding segmentation techniques. Indeed, with the support of neural networks and deep learning, it is possible to quantify structures in synchrotron phase-contrast images that were not distinguishable before. In particular, collagen bundles can be identified by their orientation and not only by their physical densities, as was made possible using conventional thresholding segmentation techniques. Indeed, localised changes in fiber orientation, curvature and strain may involve changes in regional strain transfer and mechanical function (e.g., tissue compliance), with consequent pathophysiological implications, including developmental of defects, fibrosis, inflammatory diseases, tumor growth and metastasis. Thus, the comprehension of these kinetics processes can foster and accelerate the discovery of therapeutic approaches for the maintaining or re-establishment of correct tissue tensions, as a key to successful and regulated tissues remodeling/repairing and wound healing

Influence of abutment macro- and micro-geometry on morphologic and morphometric features of peri-implant connective tissue

Objectives: The aim of the present human observational study is to provide morphologic and morphometric analysis of peri-implant connective tissue next to abutments with divergent or convergent macro-geometry and different surface micro-characteristics. Materials and Methods: Thirty patients were rehabilitated with single implants in the posterior area and one out of three different healing abutments with a one stage technique: machined divergent abutment (DIV-MAC), machined convergent abutment (CONV-MAC) or convergent abutment with ultrathin threaded surface (CONV-UTM). At 3 months post implant insertion peri-implant soft tissue was harvested; the following outcomes were investigated: histomorphometry (vertical width of connective and epithelial components) as detected by histology and polarized light; connective tissue vertical width and 3D organization as detected by synchrotron-based high-resolution phase-contrast based tomography (PhC-µCT). Results: Significant differences in connective tissue vertical dimension (aJE-AM) were found between DIV-MAC and both CONV-MAC and CONV-UTM, both by histology and PhC-µCT, with significantly higher values for the last two groups. Moreover, 2D histological analysis did not find significant differences in the junctional epithelium vertical dimension (PM-aJE). Importantly, PhC-µCT analysis revealed, at 3D level, significant greater amount and density of collagen bundles for CONV-UTM compared with the other two groups. Conclusions: Convergent abutment profiles, regardless of their surface micro-geometry, seem to favour axial development of peri-implant connective tissue. Moreover, ultrathin threaded surfaces seem associated with denser and greater connective tissue organization, which might improve peri-implant soft tissue seal

Lithography-based Ceramic Manufacturing (LCM) versus Milled Zirconia Blocks under uniaxial compressive loading: An in vitro comparative study

Aim This in vitro study aimed to compare the mechanical performance of 3D printed versus milled zirconia blocks, when subjected to uniaxial compression load, and to investigate the microstructural characteristics of the 3D printed samples, before and after the application of the load. Methods Twenty zirconia blocks (5 × 5 × 5mm3) were prepared: 10 (tests) were 3D printed with a Lithography-based Ceramic Manufacturing (LCM) printer (Cerafab S65®, Lithoz, Vienna, Austria), and 10 (controls) were milled with a 5-axis milling machine (DWX-52D®, DGShape, a Roland Company, Hamamatsu, Japan). Compression tests were carried out on all samples, using a load cell of 30 kN and crosshead speed of 0.5 mm/min, in according to the ASTM C1424-15. The elastic modulus of the material was calculated from stress/strain curve by taking compressive stress values between 50 MPa and 100 MPa. Compression data obtained were plotted as stress-strain curves. Finally, the 3D printed test samples were also observed by VEGA3 Tescan scanning electron microscope (SEM) to detect the presence of eventual defects on surface before and after compression. A statistical analysis was performed to compare the elastic modulus and the deformation in compression at maximum load of the test samples that did not break and the control samples. Results Under mechanical compression, four of the test samples reached failure, whereas all the control samples did not reach failure at the limit of the load cell. However, the 3D printed samples that did not break revealed interesting properties, such as a better modulus of elasticity (p=0.15) and a lower tendency to deformation under compression (p<0.001), when compared to the milled ones. Conclusions Within the limits of this study (experimental setting, in vitro design, only one type of force applied) milled zirconia blocks were found more resistant to compression forces than 3D printed ones