Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva.

(1) Background: PETG (polyethylene terephthalate glycol) is a transparent, inexpensive, and versatile thermoplastic biomaterial, and it is increasingly being used for a variety of medical applications in dentistry, orthopedics, tissue engineering, and surgery. It is known to have remarkable properties such as tensile strength, high ductility, and resistance to chemical insults and heat, but it can be affected by various environmental conditions. The aim of the present study was to evaluate the topographical characteristics of four thermoplastic dental appliance materials in relation to water sorption in simulated oral environments (artificial saliva samples with different pH values). (2) Methods: The following four types of PETG clear thermoplastic materials were selected for the present study: Leone (L), Crystal (C), Erkodur (E), and Duran (D). In relation to the desiccation and water-uptake stages, their water sorption (Wsp) and solubility (Wsl) were calculated, and the surface topographies were analyzed on two length scales. The surface roughness was determined using a contact profilometer, and nanoroughness measurements were generated by three-dimensional profiles using an atomic force microscope (AFM). Statistical analyses (one-way ANOVA and unpaired and paired Student t-tests) were performed. (3) Results: After saliva immersion, the weights of all samples increased, and the highest sorption was recorded in a basic environment. Among the materials, the water uptake for the L samples was the highest, and for E, it was the lowest. In relation to water solubility, significant values were registered for both the L and C samples' materials. After immersion and desiccation, a decreasing trend in microroughness was observed. The AFM high-resolution images reflected more irregular surfaces related to saliva immersion. (4) Conclusions: The sorption rates recorded in water-based artificial saliva were higher for basic pH levels, with significant differences between the samples. There were also significant differences related to the behaviors of the materials included in the study. In relation to roughness, on a microscale, the surfaces tended to be smoother after the saliva immersions, and on a nanoscale, they became more irregular.

Insights into the Cytotoxicity and Irritant Potential of Chlorhexidine Digluconate: An In Vitro and In Ovo Safety Screening.

Chlorhexidine (CHX) represents one of the most commonly used antiseptics in dentistry and other medical-pharmaceutical fields due to its broad-spectrum antimicrobial activity. However, the potential toxic events arising from its common use in practice has become a subject of increasing concern. Thus, the present study was designed to investigate the potential toxicity of CHX digluconate at concentrations covering its antibacterial properties (0.0002-0.2%) in HGF primary gingival fibroblasts, HaCaT immortalized human keratinocytes, and JB6 Cl 41-5a epidermal cells, as well as its irritant action in ovo. Our results indicate that CHX exerted a concentration- and time-dependent cytotoxicity in all cell lines, which was evidenced by the reduction in cell viability, number, and confluence, damaged cell membrane integrity, impaired cell morphology, and specific apoptotic nuclear shape. The highest cytotoxicity was caused by CHX digluconate 0.02% and 0.2%, concentrations, at which an irritant effect on the chorioallantoic membrane was also observed. The novel findings revealed in this research contribute to the overall safety profile of CHX and stand as a basis for further investigations in this regard.

Topographical and Optical Characteristics of Thermoplastic Dental Appliances Materials Related to Water Sorption.

Clear thermoplastic materials have increased in popularity in the dental field due to their various applications, combination of excellent aesthetics, and good biomechanical behavior, but they may be influenced by different environmental conditions. The purpose of the present study was to assess the topographical and optical characteristics of thermoplastic dental appliances materials relative to water sorption. PET-G polyester thermoplastic materials were evaluated in this study. Related to water uptake and desiccation stages, surface roughness was analyzed, and three-dimensional AFM profiles were generated for nano-roughness measurements. Optical CIE L*a*b* coordinates were recorded and parameters like translucency (TP), contrast ratio for the opacity (CR), and opalescence (OP) were derived. Levels of color changes were achieved. Statistical analyses were performed. Water uptake significantly increases the specific weight of the materials, and after desiccation, the mass decreases. Roughness increased after water immersion as well. Regression coefficients indicated a positive correlation between TP and a* and between OP and b*. Studied PET-G materials have a different behavior to water exposure, but for all their specific weight, they increased significantly within the first 12 h. It is accompanied by an increase in the roughness values, even if they continue to be kept below the critical mean surface roughness. On nano-level, 3D images show an increase in inhomogeneity in the network structure of particles. Slight color changes were registered.

Surface Characteristics and Color Stability of Dental PEEK Related to Water Saturation and Thermal Cycling.

(1) Background: The study was undertaken to evaluate the surface characteristics, microhardness, and color stability of PEEK materials related to water saturation and in vitro aging. (2) Methods: Custom specimens of unmodified and modified PEEK CAD/CAM materials were investigated: BioHPP, a ceramic reinforced PEEK, and Finoframe PEEK and Juvora medical PEEK, 100% PEEK materials. Forty-eight plates were sectioned in rectangular slices. The specimens were immersed in distilled water at 37 °C for a period of 28 days, and then subjected to aging by thermal cycling (10,000 cycles). Surface roughness was measured with a contact profilometer; nanosurface topographic characterization was made by Atomic Force Microscopy; Vickers hardness measurements were performed with a micro-hardness tester; color changes were calculated. All registrations were made before immersion in water and then subsequently once a week for 4 weeks, and after thermocycling. (3) Results: The studied reinforced and unfilled PEEK materials reached water saturation after the first week of immersion, without significant differences between them. The most affected from this point of view was the reinforced PEEK material. Thermocycling induces a significant increase inmicroroughness, without significant differences between the studied materials. In relation to the nanosurface topography and roughness, the reinforced PEEK material was the least modified by aging. The color changes after 4 weeks of water immersion and one year of simulated in vitro aging ranged from extremely slight to slight, for all materials. (4) Conclusions: Water absorption was associated with a decrease in microhardness. Surface characteristics are affected by water immersion and thermocycling. Perceivable or marked color changes of the materials were not detected during the study.

COVID-19: Main findings after a year and half of unease and the proper scientific progress (Review).

Since the emergence of the disease in late December 2019, numerous studies have been published to date regarding clinical, laboratory and treatment aspects associated with COVID-19. The present study attempts to compare and unify the clinical, para-clinical and therapeutic aspects that have come to light regarding coronavirus disease-19 (COVID 19), mainly in adults. Between April 2020 and September 2021, a comprehensive systematic literature review was performed, which we added to from our own medical experiences. The search was performed on the PubMed, Scopus and Google Scholar databases, comprising studies with analyzable data that were identified alongside studies and documents containing general scientific data. All published studies were written in English, and were from different countries. A 95% confidence interval (CI95) was also calculated for almost each study using the Wilson formula. When compared with preliminary reports between December 2019 and January 2020, the most frequent symptoms were still identified as being fever (68.6%; CI95: 67.5-69.7) and cough (72.7%; CI95: 71.7-73.8). Nevertheless, asymptomatic cases also increased (by 21.4%; CI95: 16.6-27.1). Severe and critical cases accounted for 10.4% (CI95: 9.6-11.1) of all cases. The mean fatality rate was found to be 4% (CI95: 3.6-4.5). The primary co-morbidity found was hypertension (28.9%; CI95: 27-30.8), followed by other underlying cardiovascular diseases (15.4%; CI95: 13.9-16.9) and diabetes (14.5%; CI95: 13.1-16.1). The majority of studies showed lower white blood cell numbers with neutropenia and lymphopenia, and lower platelet levels. The levels of the biomarkers C-reaction protein and erythrocyte sedimentation rate were positive in all studied cases alongside other lab tests, such as examining the D-dimer levels and those of other hepatic, cardiac and renal injury markers. The procalcitonin level was also found to be elevated in many cases, resulting in high usage of antibiotics (83.7%; CI95: 81.2-85.9). Approximately 31.6% (CI95: 29.1-34.1) of the patients required non-invasive ventilation, whereas 9.9% (CI95: 8.1-12.1) of the patients were intubated or placed on extracorporeal membrane oxygenation. The most used antivirals were ribavirin (67.3%; CI95: 63.4-70.9), oseltamivir (52.5%; CI95: 49.4-55.5) and Arbidol™ (34.5%; CI95: 32-37.1). General admittance to the intensive care unit was ~7.2% (CI95: 6.5-7.9) of patients.

Optical Properties and Color Stability of Dental PEEK Related to Artificial Ageing and Staining.

Considering that the processes of PEEK discoloration caused by either intrinsic or extrinsic factors require elucidation, the aim of this study was to investigate the long-term effect of the combined action of ageing and immersing solutions on the optical properties and color stability of PEEK material, related to surface processing (polishing or glazing). (2) Methods: This study aims to determine the influence of different ageing and staining protocols on optical properties, color changes, and surface roughness of a reinforced PEEK material (bioHPP, Bredent, Senden, Germany). For ageing, specimens were submitted to 5000 cycles in a 55 °C bath and a 5 °C bath filled with distilled water. For staining, thermal cycling was performed in a hot coffee bath (55 °C) and a bath filled with distilled water (37 °C) and in a cold juice bath (5 °C) and a bath filled with distilled water (37 °C). Translucency (TP) and opalescence (OP) parameters were determined, the total color change value (ΔΕ*) was calculated, specimens' surface roughness was analyzed, and statistical analyses were performed. (3) Results: The mean TP values of the studied samples were in the interval of 1.25-3.60, which is lower than those reported for natural teeth or other aesthetic restoration materials. The OP values of PEEK were registered in the range of 0.27-0.75, being also lower than those of natural teeth or other aesthetic restoration materials. OP has a very strong positive relationship with TP. The mean registered Ra values for all subgroups were below 0.13 µm. Artificial ageing and staining in hot coffee proved to increase the roughness values. (4) Conclusions: The glazing of PEEK has a favorable effect on surface roughness and opalescence, irrespective of the artificial ageing or staining protocols. Artificial ageing damages the color stability and roughness of PEEK, regardless of surface processing, and decreases the translucency and opalescence of glazed surfaces. Immersion in hot coffee leads to perceivable discolorations.

COVID-19 and Its Repercussions on Oral Health: A Review.

In 2019, a new type of coronavirus, SARS-CoV-2, the causing agent of COVID-19, was first detected in Wuhan, China. On 11 March 2020, the World Health Organization declared a pandemic. The manifestations of COVID-19 are mostly age-dependent and potentially more severe in cases with involved co-morbidities. The gravity of the symptoms depends on the clinical stage of the infection. The most common symptoms include runny nose and nasal congestion, anosmia, dysgeusia or hypogeusia, diarrhea, nausea/vomiting, respiratory distress, fatigue, ocular symptoms, diarrhea, vomiting, and abdominal pain. These systemic conditions are often accompanied by skin and mucosal lesions. Oral lesions reported in patients with COVID-19 include: herpex simplex, candidiasis, geographic tongue, aphthous-like ulcers, hemorrhagic ulcerations, necrotic ulcerations, white hairy tongue, reddish macules, erythematous surfaces, petechiae, and pustular enanthema. It is still unclear if these manifestations are a direct result of the viral infection, a consequence of systemic deterioration, or adverse reactions to treatments. Poor oral hygiene in hospitalized or quarantined COVID-19 patients should also be considered as an aggravating condition. This narrative review is focused on presenting the most relevant data from the literature regarding oral manifestations related to SARS-CoV-2, as well as the challenges faced by the dental system during this pandemic. A routine intraoral examination is recommended in COVID-19 patients, either suspected or confirmed, as, in certain cases, oral manifestations represent a sign of severe infection or even of a life-threatening condition. It is our belief that extensive knowledge of all possible manifestations, including oral lesions, in cases of COVID-19 is of great importance in the present uncertain context, including new, currently emerging viral variants with unknown future impact.

Caries Prevalence Associated with Oral Health-Related Behaviors among Romanian Schoolchildren.

Oral health-related behaviors and living conditions play an important role in general and oral health. This study aimed to evaluate caries prevalence and severity in schoolchildren residing in rural and urban areas of Romania, and to correlate these with oral health-related behaviors. An estimation of the required sample size was conducted (sampling error of ±3% at a 95% confidence level), followed by the stratification of administrative units and then the selection of 49 schools. The Hurdle approach was used to analyze the dataset, requiring two sets of analyses for each outcome variable: a multilevel binary model to predict prevalence, and a multilevel Poisson analysis using only non-zero values. The mean and standard deviation (SD) for the dentinal caries index was 4.96 (5.33). Girls were more likely to have non-zero restoration codes (ß = 0.14, SE = 0.08, p < 0.05). Low education levels of each parent were associated with an increased likelihood of having non-zero carious tooth surfaces (ß = 0.23, SE = 0.06, p = 0.01; ß = 0.22, SE = 0.06, p < 0.01). The presence of cavities was predicted by the consumption of carbonated soft drinks (ß = 0.19, SE = 0.07, p < 0.01), candies (ß = 0.13, SE = 0.06, p < 0.01), sweetened milk (ß = 0.12, SE = 0.06, p < 0.05), tea (ß = 0.16, SE = 0.08, p < 0.05), or cocoa (ß = 0.13, SE = 0.06, p < 0.05). Furthermore, the non-zero values of the dentinal caries index were more likely in rural schools (ß = -0.37, SE = 0.11, p < 0.01), and a negative association between the county development index and the fillings/restorations index (ß = -0.01, SE = 0.01, p < 0.05) was also established. The outcome of this research highlights that the presence of caries (dentinal caries index) in Romanian schoolchildren is influenced by their socioeconomic background, as well as their specific consumption behaviors.

Advanced Biomaterials and Techniques for Oral Tissue Engineering and Regeneration-A Review.

The reconstruction or repair of oral and maxillofacial functionalities and aesthetics is a priority for patients affected by tooth loss, congenital defects, trauma deformities, or various dental diseases. Therefore, in dental medicine, tissue reconstruction represents a major interest in oral and maxillofacial surgery, periodontics, orthodontics, endodontics, and even daily clinical practice. The current clinical approaches involve a vast array of techniques ranging from the traditional use of tissue grafts to the most innovative regenerative procedures, such as tissue engineering. In recent decades, a wide range of both artificial and natural biomaterials and scaffolds, genes, stem cells isolated from the mouth area (dental follicle, deciduous teeth, periodontal ligament, dental pulp, salivary glands, and adipose tissue), and various growth factors have been tested in tissue engineering approaches in dentistry, with many being proven successful. However, to fully eliminate the problems of traditional bone and tissue reconstruction in dentistry, continuous research is needed. Based on a recent literature review, this paper creates a picture of current innovative strategies applying dental stem cells for tissue regeneration in different dental fields and maxillofacial surgery, and offers detailed information regarding the available scientific data and practical applications.

Trueness and Precision of Two Intraoral Scanners: A Comparative In Vitro Study.

The aim of this study was to evaluate the accuracy of two intraoral scanners used in the dental office. A molar fixed in a typodont was prepared for a ceramic onlay. The preparation was scanned using a high-resolution scanner (reference scanner) and saved as stereolithography (STL) format. The prepared resin molar was scanned again using the intraoral scanners, and all the scans were saved as well in STL format. All STL files were compared using metrology software (Geomagic Control X). Overlapping the meshes allowed the assessment of the scans in terms of trueness and precision. Based on the results of this study, the differences of trueness and precision between the intraoral scanners were minimal.