SEM characterization and ageing analysis on two generation of invisible aligners

Abstract Background: The purpose of the in vitro study is to investigate and compare the morphological features and the chemical stability in weight of two different polyurethane-based blends, Smart Track (LD30) and Exceed30 (EX30), used for orthodontic aligners manufacture before and after the oral usage. Methods: Twenty orthodontic aligners were randomly selected: 10 LD30 and 10 EX30, each group was divided in two subgroups, never used and intra-orally aged. By the employment of a Stereomicroscope, a section of 5 × 5 mm was cut from the buccal surface of the incisal region of each aligner. All samples were subjected to Scanning Electron Microscopy and Ageing tests in different solutions to simulate the hostility of the oral environment. The statistical method used was t-test. Results: At SEM images, LD30 appears more homogeneous in texture respect to EX30. However, after clinical usage, both materials show significant structural alterations: findings have been supported by higher magnifications at SEM, by which it is clearly to observe many superficial cracks cross through the polymer structures of LD30U, absent in never used samples. LD30U surface becomes also smoother due to the disappearance of most of the conglomerates, but at the same time also rougher while EX30U shows a greater irregularity and porosity in which large and deep cracks are also highlighted. Although these changes occur persistently, in the aging tests no significant weight loss from both materials has been found, confirming the initial hypothesis of a good chemical stability and safety of both polyurethane mixtures even in conditions of severe hostility. Conclusion: LD30 is the expression of the technological evolution of EX30, this is made evident above all by its morphological architecture, more homogeneous and defined but also by the chemical stability that can be appreciated even in evident critic situations

Orofacial signs and dental abnormalities in patients with Mulvihill-Smith syndrome: A literature review on this rare progeroid pathology

BACKGROUND: Mulvihill-Smith syndrome is a rare sporadic condition that was first recognized in 1975. A total of 11 cases have been described in the literature. The aim of this study was to describe the orofacial signs and dental anomalies, their frequency, and the relationship between Mulvihill-Smith syndrome and other progeroid syndromes via a review of the literature.METHODS: A systematic PubMed search was performed to retrieve articles published between 1975 and the present day that described patients affected by Mulvihill-Smith syndrome. The search identified 14 articles, and data on 11 patients were extracted from the selected articles.RESULTS: A total of 7 patients (63.6%) affected by Mulvihill-Smith syndrome were described as having a typical "bird" face. Dental abnormalities, including irregular shape, enamel defects, hypodontia, and taurodontism, were described in 6 patients (54.5%). All patients (100%) had multiple pigmented nevi on the face and a lack or thinning of subcutaneous tissue around the neck and face. Three patients with Mulvihill-Smith syndrome exhibited early onset of tumors of the gastrointestinal tract, including the tongue.CONCLUSION: Mulvihill-Smith syndrome is a clinically complex disease that may be caused by a single gene mutation. Numerous different tissues of the body are affected. This analysis of the orofacial signs may help clinicians to diagnose this rare pathology

In vitro evaluation of structural factors favouring bacterial adhesion on orthodontic adhesive resins

Bacterial adhesion to the surface of orthodontic materials is an important step in the formation and proliferation of plaque bacteria, which is responsible for enamel demineralization and periodontium pathologies. With the intent of investigating if adhesive resins used for bracket bonding are prone to bacteria colonization, the surface roughness of these materials has been analyzed, combining information with a novel methodology to observe the internal structures of orthodontic composites. Scanning electron microscopy, combined with focus ion bean micromachining and stylus profilometry analyses, were performed to evaluate the compositional factors that can influence specific pivotal properties facilitating the adhesion of bacteria to the surface, such as surface roughness and robustness of three orthodontic adhesive composite resins. To confirm these findings, contact angle measurements and bacteria incubation on resin slide have been performed, evaluating similarities and differences in the final achievement. In particular, the morphological features that determine an increase in the resins surface wettability and influence the bacterial adhesion are the subject of speculation. Finally, the focused ion beam technique has been proposed as a valuable tool to combine information coming from surface roughness with specific the internal structures of the polymers

Oral management of adult patients undergoing hematopoietic stem cell transplantation.

Chemotherapy and hematopoietic stem cell transplantation (HSCT) are the current treatments for patients with hematological diseases; they result in myelosuppression, and increase the susceptibility of patients to severe infections. The oral cavity is a potential site of complications in HSCT patients, because it is the entrance for agents that can cause systemic infections; it is one of the most frequent locations for side effects deriving from conditioning therapy. The importance of dental pre-chemotherapy and transplant prescription is often stressed, since both therapies depress the immune system and platelets, making each intervention at this stage a high risk. The aim of this article is to review the potential complications of HSCT, and to extrapolate from the scientific literature the treatments and timeframes in which dental therapies can be performed, avoiding important risks for patients

Perspectives on multisensory perception disruption in idiopathic environmental intolerance: a systematic review

Multiple chemical sensitivity (MCS) also known as idiopathic environmental intolerance/illness (IEI) encompasses a cohort of subjective symptoms characterized by susceptibility to a wide spectrum of environmental compounds, causing symptoms involving various organs and a decrease in quality of life. The aim of this systematic review is to summarize evidence about MCS, with focus on indexed studies analyzing sensory pathway-related disorders. Medical databases were searched for English language articles related to the topic, published between 1965 and 2017 in academic, peer-reviewed journals. Particular focus was concentrated on articles depicting disturbances involving sensory organs. References of the relevant articles were examined to identify additional significant documents. Fifty-eight studies were eligible for full text review. Of these, 34 studies met the selection criteria and were included in this analysis. Many variables, such as different diagnostic criteria, lack of homogeneous symptom questionnaires and the general incidence of personality traits in control subjects, biased studies as confounding factors. However, moderate evidences show that sensory pathways are somewhat altered, especially with respect to information processing in the limbic system and related cortical areas. Recent studies suggested the presence, in MCS cohorts, of attention bias, sensitization and limbic kindling, as well as recently revealed subclinical organic alterations along sensory pathways. Evidences are consistent with MCS/IEI to be the result of a neural altered processing of sensorial ascending pathways, which combined with peculiar personality traits constitutes the underpinning of a multisensory condition needing multidisciplinary clinical approach

Management of Surgical Third Lower Molar Extraction and Postoperative Progress in Patients With Factor VII Deficiency: A Clinical Protocol and Focus on This Rare Pathologic Entity

Purpose The purpose of the present study was to analyze the management of surgical third molar extraction and postoperative progress in patients with a diagnosis of factor VII deficiency. Close collaboration between the oral-maxillofacial surgeon and hematologist will allow the team to categorize the risk and operate safely, thereby minimizing the incidence and severity of intraoperative and postoperative complications. Materials and Methods The present retrospective study included 7 patients with factor VII deficiency who had undergone third lower molar surgery. Their factor VII deficiency ranged from 10.5 to 21.0%. Recombinant activated factor VII (rFVIIa) (coagulation factor VIIa [recombinant]; NovoSeven RT; Novo Nordisk, Bagsvaerd, Denmark) was transfused intravenously in a single dose of 25 \u3bcg/kg body weight, 30 minutes before surgical extractions. After the surgery, betamethasone, an analgesic, and an ice pack were administered. Results Pretreatment with recombinant activated factor VII resulted in excellent hemostasis. No hemorrhagic complications and no postoperative major bleeding were observed. Conclusions The extraction of the third lower molar appears to be a safe procedure for patients with factor VII deficiency when appropriate prophylaxis with rFVIIa is used

Adhesion of resin-based materials to eroded dentin: a systematic review and meta-analysis

Objective To determine whether bond strength to eroded dentin is similar to values found for sound dentin, before and after additional treatments. Materials and methods MeSH terms and keywords relative to the topics ‘adhesion to dentin’ and ‘eroded dentin’ were searched in the Pubmed and the Scopus databases. In vitro studies that compared the bond strength to sound and eroded dentin were selected. The following data were included: pH-cycling model, materials, treatments, bond strength tests, and failure modes. Bond strength values were compared by meta-analyses and the failure modes were analyzed for random effects. Results The bond strength data of the 23 studies included were extracted by the reviewers and assessed by meta-analyses. Low risk of bias was found most frequently. Sound × Eroded Dentin comparisons revealed higher bond strength to sound dentin. When compared with untreated eroded dentin, treatments such as NaOCl, E64, CHX and PAA acid, PPA and RI primer, showed high and durable bond strength values (p˂0.0001). Mixed failures were the most frequent type (39.26%), followed by adhesive (38.21%) and cohesive failures (6.15%). Conclusions The bond strength to eroded dentin can be improved by mechanical and chemical strategies, applied before or during the adhesive protocol

Micro-computed tomography evaluation of microleakage of Class II composite restorations: An in vitro study

Objective: The aim of this study is to investigate the microleakage attained with three resin‑based material used to restore deep Class II cavities. A null hypothesis was chosen: there is no difference in microleakage among the tested materials. Materials and Methods: A total of 30 Class II cavities were prepared in freshly extracted molars with the proximal mesial and distal margins located, respectively, 1.5 mm apically and 1.5 mm coronally to the cementum‑enamel junction. Restorations were completed using a three‑step enamel‑dentin adhesive system “Etch and Rinse,” margins were relocated using a micro‑hybrid, preheated, or flowable composite and restorations were then completed using a conventional composite. All samples were coated with nail varnish with the exception of an area along the margins and apex was sealed using epoxide cement and then thermocycled (30‑s dwell time, 5°C/55°C, 1000 cycles). A 50% ammoniac AgNO3 solution was used as tracer according to Tay’s protocol. The microleakage analysis was performed using a microtomography system Sky‑scan 1072 (SKYSCAN, Kartuizersweg 3B 2550, Konitch, Belgium). Results: The mean microleakage of all the tested materials showed greater leakage in the cementum margins; flowable composite exhibit greater leakage among the groups. Significant differences (P < 5%) within groups in both enamel and dentin margins were present. None of the tested materials eliminated marginal microleakage. Preheated composite showed significantly lesser microleakage. Conclusion: Tested materials showed statistical differences in microleakage; thus, the null hypothesis has been rejected. Within the limitations of the present experimental procedure, it can be concluded that flowable resin composite should be avoided at the dentin/cementum margi

Far Infrared Technology (FIT) Therapy Patches, Protects from Inflammation, Oxidative Stress and Promotes Cellular Vitality

It is known from the most recent literature that far-infrared (FIR) radiations promote a broad spectrum of therapeutic benefits for cells and tissues. To identify molecular mechanisms by which FIT patches, as a far infrared technology, protects against damage caused by inflammatory process and oxidative stress. Endothelial cells (HUVEC, Human Umbilical Vein Endothelial Cells) were used as in vitro experimental model. HUVEC were stimulated with a pro-inflammatory cytokine, TNF-α, or hydrogen peroxide (H2O2) to induce oxidative stress. As markers of inflammation were evaluated: VCAM1 (Vascular Cell Adhesion Molecule 1), ICAM1 (Intercellular Adhesion Molecule 1) and E-Selectin by Western Blot analysis. Oxidative stress was assessed by cytofluorimetric analysis. The experiments were performed on control cells (no patch) or in cells treated with the FIT infrared technology applied on the basis of the culture plate. HUVEC stimulated with TNF-α and treated with FIT patches had significant reduction of the expression of VCAM1, ICAM1 and E-Selectin (p<0.05). HUVEC stimulated with H2O2 and treated with FIT patches were significantly protected from oxidative stress (p <0.01) when compared to control cells. We measured cell viability and proliferation in HUVEC and HEK-293 (Human embryonic kidney cells) cells by MTT assay. HEK-293 and HUVEC treated with FIT patches showed a significantly higher percentage of basal vitality compared to control cells (p<0.0001 for HEK-293, p<0.05 for HUVEC). FIT therapy patches - infrared technology, through these protective mechanisms, could be used in all pathologies where an increase in inflammation, oxidative stress and degenerative state are present

ElectroBond Improves Immediate Dentin Microtensile Bond Strength of Two Etch-and-Rinse Adhesives

Purpose: The aim of this study was to investigate whether an electrical device for dental adhesive application (ElectroBond) influences bonding of two-step etch-and-rinse adhesives. Materials and Methods: Human teeth were selected and cut perpendicularly to their long axis to expose middle/deep dentin. Specimens were then longitudinally sectioned into halves (experimental and control halves) to create two similar bonding substrates. Experimental halves were bonded using an ElectroBond-assisted application, while control halves were bonded with disposable sponges. The adhesives tested were Adper Scotchbond 1XT and XP-BOND. Bonded specimens were submitted to the microtensile bond strength test. Additional adhesive interfaces were prepared and processed for nanoleakage investigation involving TEM examination. Results: The microtensile bond test revealed higher values (p < 0.05) for both adhesives if ElectroBond was used during layering (55.5 +/- 7.9 IVIPa for Adper Scotchbond 1XT and 54.7 +/- 7.1 IVIPa for XP-BOND) compared to the conventional mechanical adhesive application technique (41.1 +/- 6.1 MPa for Adper Scotchbond 1XT and 38.0 +/- 7.8 MPa for XP-BOND). No difference between the two adhesives was found under the same application conditions. With electricity-assisted application, TEM micrographs revealed a significant decrease in nanoleakage expression compared to the controls. Conclusion: The use of an electric current produced by ElectroBond during the application of two-step etch-and-rinse adhesives may enhance resin impregnation, thus improving dentin hybridization. Further studies should be done to confirm that this device can similarly improve adhesive application in vivo