ENTPD1 (CD39) and NT5E (CD73) expression in human medulloblastoma: an in silico analysis.

Medulloblastoma is the most common malignant tumor in the pediatric population. Its classification has incorporated key molecular variations alongside histological characterization. CD39 (also known as ENTPD1) and CD73 (also known as NT5E), enzymes of the purinergic signaling pathway, act in synergy to generate extracellular adenosine, creating an immunosuppressive tumor microenvironment. Our study examined the expression of mRNA of these genes in previously described transcriptome data sets of medulloblastoma patient samples from the Cavalli Cohort (n = 763). Survival distribution was estimated according to the Kaplan-Meier method using a median cut-off and log-rank statistics (p ≤ 0.05). In non-WNT and non-SHH medulloblastoma Group 4 (n = 264), the high expression of ENTPD1 and NT5E was significantly related to a lower overall survival (p = 2.7e-04; p = 2.6e-03). In the SHH-activated group (n = 172), the high expression of ENTPD1 was significantly related to lower overall survival (p = 7.8e-03), while the high expression of NT5E was significantly related to greater overall survival (p = 0.017). In the WNT group (n = 63), the expressions of ENTPD1 and NT5E were not significantly correlated with overall survival (p = 0.212; p = 0.101). In non-WNT and non-SHH medulloblastoma Group 3 (n = 113), the high expression of ENTPD1 was significantly related to greater survival (p = 0.034), while expression of NT5E was not significantly related to survival of patients (p = 0.124). This in silico analysis indicates that ENTPD1 (CD39) and NT5E (CD73) can be seen as potential prognostic markers and therapeutic targets for primary medulloblastomas in non-WNT and non-SHH Group 4.

Implementation of Robot-assisted Urologic Surgeries Using Hugo RAS System in a High-volume Robotic "Da Vinci Xi" Center: Outcomes and Initial Experience.

OBJECTIVE: To describe the trocar disposition, docking angles, surgical times, functional outcomes, and complications experienced during the first 30 surgeries with Hugo RAS platform performed by a high-volume Da Vinci Xi's surgeon. METHODS: Retrospective, observational, descriptive study was performed between May-December 2023. Safety and feasibility of the procedures were evaluated considering console and docking time (minutes), perioperative complications (Clavien-Dindo classification), blood loss (mL), and collision of the arms during the procedures (Yes/No). For radical prostatectomies (RARP) the urinary continence and sexual function were also evaluated. RESULTS: RARP, simple prostatectomies (RASP), partial nephrectomies (RAPN), and cystectomy (RARC) were performed. Trocar placement, docking, and bed assistant ergonomics were important challenges. Patient positioning, trocar placement, and robotic arm positioning had to be adapted. The median console operative time for RARP and RASP was 78 (60-120) minutes and 79 (58-125) minutes, respectively. The median docking time for both RARP and RASP was 10 (5-20) minutes. Of patients undergoing RARP, 94.5% recovered sexual function and no patient used more than one PAD per day after 90days of the surgery. The median console operative and docking time for RAPN was 82 (80-130) minutes and 12 (7-19) minutes, respectively. Blood loss in all patients was less than 200 mL and all none procedure presented major complications. CONCLUSION: For a high-volume surgeon with motivated and well-trained multidisciplinary team, the implementation of HUGO RAS system for urological program is safe and smooth. Adaptations were necessary to achieve equivalent surgical technique and results. Docking position and bed assistant ergonomics are the major challenges.

Outcomes of ablative therapy and radical treatment for prostate cancer: a systematic review and meta-analysis

ABSTRACT Purpose: To compare biochemical recurrence, sexual potency and urinary continence outcomes of ablative therapy and radical treatment (radical prostatectomy or radiotherapy with androgen deprivation therapy). Material and methods: A systematic review and meta-analysis followed the PRISMA guidelines were performed. We searched MEDLINE/PubMed. Biochemical recurrence at three and five years; incontinence rate (patients who used one pad or more) and erectile dysfunction rate at 12 and 36 months (patients who did not have sufficient erection to achieve sexual intercourse) were evaluated. The Mantel-Haenszel method was applied to estimate the pooled risk difference (RD) in the individual studies for categorical variables. All results were presented as 95% confidence intervals (95%CI). Random effects models were used regardless of the level of heterogeneity (I²). (PROSPERO CRD42022296998). Results: Eight studies comprising 2,677 men with prostate cancer were included. There was no difference in biochemical recurrence between ablative and radical treatments. We observed the same biochemical recurrence between ablative therapy and radical treatment within five years (19.3% vs. 16.8%, respectively; RD 0.07; 95%CI=-0.05, 0.19; I2=68.2%; P=0.08) and continence rate at 12 months (9.2% vs. 31.8%, respectively; RD −0.13; 95%CI, −0.27, 0.01; I2=89%; P=0.32). When focal treatment was analyzed alone, two studies with 582 patients found higher erectile function at 12 months in the ablative therapy group than in the radical treatment (88.9% vs. 30.8%, respectively; RD −0.45; 95%CI −0.84, −0.05; I2=93%; P=0.03). Conclusion: Biochemical recurrence and urinary continence outcomes of ablative therapy and radical treatment were similar. Ablative therapy appears to have a high rate of sexual potency.

Antarctica's hidden mycoviral treasures in fungi isolated from mosses: A first genomic approach.

This study investigates the presence of mycoviruses in Antarctic fungi and elucidates their evolutionary relationships. To achieve this, we aligned mycoviral gene sequences with genomes of previously sequenced Antarctic endophytic fungi, made available by our research group and accessible via Joint Genome Institute. Our findings reveal that the most prevalent genetic regions in all endophytic fungi are homologous to Partitiviruses, Baculoviridae, and Phycodnaviridae. These regions display evidence of positive selection pressure, suggesting genetic diversity and the accumulation of nonsynonymous mutations. This phenomenon implies a crucial role for these regions in the adaptation and survival of these fungi in the challenging Antarctic ecosystems. The presence of mycoviruses in Antarctic endophytic fungi may indicate shared survival strategies between the virus and its host, shedding light on their evolutionary dynamics. This study underscores the significance of exploring mycoviruses within endophytic fungi and their contributions to genetic diversity. Future research avenues could delve into the functional implications of these conserved mycoviral genetic regions in Antarctic endophytic fungi, providing a comprehensive understanding of this intriguing association and genomic retention of viral region in fungi.

Using native plants to evaluate urban metal pollution and appoint emission sources in the Brazilian Steel Valley region.

In southeastern Brazil, the city of Ipatinga is inserted in the Steel Valley Metropolitan Region, which hosts the largest industrial complex for flat-steel production in Latin America, while also having one of the largest vehicle fleets in the entire country. Since potentially toxic elements (PTEs) are not emitted solely by industries, yet also by vehicular activity, the predominant emission source can be determined by evaluating the ratio between different elements, which are called technogenic tracers. We performed a biomonitoring assay using two tropical legumes, Paubrasilia echinata and Libidibia ferrea var. leiostachya, aiming to assess chemical markers for the origin of emissions in the region, distinguishing between different anthropogenic sources. Plants were exposed for 90 days in four urban sites and in a neighboring park which served as reference. After the experimental period, plants were evaluated for trace-metal accumulation. L. ferrea var. leiostachya retained lower amounts of metals associated with vehicular and industrial emission. The opposite was found with P. echinata, a species which should be recommended for biomonitoring of air pollution as a bioaccumulator. Plants of P. echinata were enriched with Fe, Al, Ni, Cr, and Ba, whereas plants of L. ferrea var. leiostachya were enriched with Fe, Cu, and Co. In both species, Fe was the element with which plants were enriched the most. Plants showed highest iron enrichment at Bom Retiro, the site downwind to the steel industry, which has shown to be the main particle emission source in the region.

Can the Remaining Coronal Tooth Structure Influence the Mechanical Behavior of Nonpost Full Crowns?

OBJECTIVES: This study investigated the impact of the remaining coronal tooth structure on the mechanical behavior of nonpost (NP) full crowns on endodontically treated maxillary central incisors. MATERIALS AND METHODS: Forty bovine incisors with NP and 2-mm of ferrule were divided into four groups based on the remaining structure: complete 2-mm ferrule (NP-2), absence of mesial and distal ferrule effect (NP-BL), absence of buccal and lingual ferrule effect (NP-MD), and no ferrule (NP-0). The specimens underwent a stepwise stress fatigue test until fracture occurred, and stress distribution was analyzed using in silico finite element analysis (FEA). Additionally, groups with endodontic posts (P) were simulated in the FEA. RESULTS: The results showed that the survival rates varied among the different groups under oblique loading. The NP-2 group exhibited the highest survival rate, with all samples enduring loads up to 200 N and some surviving up to 520 N. The NP-MD and NP-BL groups had lower survival rates, while the NP-0 group had the poorest survival rate. The predominant failure mode was a nonrepairable root fracture. FEA results indicated no significant difference between groups with and without posts. NP intraradicular restorations on nonweakened roots with a minimum height of 2mm and partial or total ferrule thickness of 1mm offer a promising treatment option. CONCLUSION: A complete 2-mm ferrule was found to be the most favorable configuration for NP full crowns. However, maintaining the remaining tissue is crucial, as both combinations with preserved ferrule effect exhibited superior behavior in terms of fatigue and fracture load compared to the group with no ferrule. These findings contribute to understanding the mechanical considerations for NP full crowns and provide insights into treatment planning and design choices in restorative dentistry.

Outcomes of ablative therapy and radical treatment for prostate cancer: a systematic review and meta-analysis.

PURPOSE: To compare biochemical recurrence, sexual potency and urinary continence outcomes of ablative therapy and radical treatment (radical prostatectomy or radiotherapy with androgen deprivation therapy). MATERIAL AND METHODS: A systematic review and meta-analysis followed the PRISMA guidelines were performed. We searched MEDLINE/PubMed. Biochemical recurrence at three and five years; incontinence rate (patients who used one pad or more) and erectile dysfunction rate at 12 and 36 months (patients who did not have sufficient erection to achieve sexual intercourse) were evaluated. The Mantel-Haenszel method was applied to estimate the pooled risk difference (RD) in the individual studies for categorical variables. All results were presented as 95% confidence intervals (95%CI). Random effects models were used regardless of the level of heterogeneity (I²). (PROSPERO CRD42022296998). RESULTS: Eight studies comprising 2,677 men with prostate cancer were included. There was no difference in biochemical recurrence between ablative and radical treatments. We observed the same biochemical recurrence between ablative therapy and radical treatment within five years (19.3% vs. 16.8%, respectively; RD 0.07; 95%CI=-0.05, 0.19; I2=68.2%; P=0.08) and continence rate at 12 months (9.2% vs. 31.8%, respectively; RD -0.13; 95%CI, -0.27, 0.01; I2=89%; P=0.32). When focal treatment was analyzed alone, two studies with 582 patients found higher erectile function at 12 months in the ablative therapy group than in the radical treatment (88.9% vs. 30.8%, respectively; RD -0.45; 95%CI -0.84, -0.05; I2=93%; P=0.03). CONCLUSION: Biochemical recurrence and urinary continence outcomes of ablative therapy and radical treatment were similar. Ablative therapy appears to have a high rate of sexual potency.

Raciocínio ético nas decisões médicas: dilema médico-paciente / Ethical reasoning in medical decisions: the physician-patient dilemma / Razonamiento ético en las decisiones médicas: dilema médico-paciente

Resumo A ética é essencial para garantir uma prática médica responsável e comprometida com o bem-estar do paciente e da sociedade. Diante disso, a compreensão da autonomia do paciente e sua participação ativa nas decisões sobre tratamentos e procedimentos médicos são fundamentais. Realizou-se revisão sistemática da literatura, entre dezembro de 2018 e maio de 2023, com o objetivo de auxiliar o debate ético e a conduta profissional acerca do que deve ser ponderado em uma situação de conflito entre a decisão médica e a vontade do paciente e, assim, fornecer perspectivas sobre o gerenciamento dessa temática. Os 18 artigos selecionados abordam questões éticas relacionadas à relação médico-paciente, destacando a importância das diretivas antecipadas de vontade, comunicação honesta e respeito à autonomia do paciente. Assim, busca-se fornecer perspectivas e orientações para o gerenciamento de conflitos éticos na prática médica.

Abstract Ethics is essential to ensure responsible medical practice, committed to the well-being of patients and society. Hence, understanding patient autonomy and their active participation in decisions about treatments and medical procedures is paramount. A systematic literature review was conducted on articles published between December 2008 and May 2023 to assist in the ethical debate and professional conduct about what should be considered in a conflict between the medical decision and the patient's wishes, and thus provide perspectives on how to manage this issue. The 18 articles selected address ethical issues related to physician-patient relations, highlighting the importance of advance directives, honest communication and respect for patient autonomy. We aim to provide perspectives and guidelines for managing ethical conflicts in medical practice.

Resumen La ética es esencial para garantizar una práctica médica responsable y comprometida con el bienestar de los pacientes y la sociedad. Así, es fundamental comprender la autonomía del paciente y su participación activa en las decisiones sobre tratamientos y procedimientos médicos. Se realizó una revisión sistemática de la literatura entre diciembre de 2018 y mayo de 2023, con el objetivo de aportar al debate ético y la conducta profesional sobre lo que debe considerarse en una situación de conflicto entre la decisión médica y la voluntad del paciente, y así proporcionar perspectivas sobre la gestión de este tema. Los 18 artículos seleccionados abordan cuestiones éticas sobre la relación médico-paciente, destacando la importancia de las voluntades anticipadas, la comunicación honesta y el respeto a la autonomía del paciente. Así, se espera ofrecer perspectivas y directrices para gestionar los conflictos éticos en la práctica médica.

ENTPD1 (CD39) and NT5E (CD73) expression in human glioblastoma: an in silico analysis.

Glioblastoma (GB) is the most common primary brain tumor in adults and carries a dismal prognosis, despite the best available treatment. The 2021 WHO Classification of CNS tumors incorporated molecular profiling to better define the characteristics and prognosis of tumor types and subtypes. These recent advances in diagnosis have not yet resulted in breakthrough therapies capable of shifting the treatment paradigm. NT5E/CD73 is a cell surface enzyme that participates in a complex purinergic pathway in synergy with ENTPD1/CD39 producing extracellular adenosine (ADO) from ATP. ADO promotes tumor progression by inducing immunosuppression, stimulating adhesion, invasion, and angiogenesis. In this study, we performed an in silico analysis of 156 human glioblastoma samples in an unexplored public database to investigate the transcriptional levels of NT5E and ENTPD1. The analysis revealed a significant increase in transcription levels of the genes under study in GB samples versus non-tumor brain tissue samples, in concordance with previous studies. High transcriptional levels of NT5E or ENTPD1 were independently related to a decrease in overall survival (p = 5.4e-04; 1.1e-05), irrespective of the IDH mutation status. NT5E transcriptional levels were significantly higher in GB IDH wild-type patients compared to GB IDH-mutant; however, ENTPD1 levels showed no significant difference, p ≤ 0.001. This in silico study indicates the need for a deeper understanding of the purinergic pathway relation to GB development, also inspiring future population studies that could explore ENTPD1 and NT5E not only as prognostic markers but also as potential therapeutic targets.

Severe hypercalcemia caused by repeated mineral oil injections: a case report

SUMMARY Hypercalcemia is a frequent condition in clinical practice and when the most frequent causes are excluded, etiological diagnosis can be challenging. A rare cause of PTH-independent hypercalcemia is described in the present case report. A male adult with a history of androgenic-anabolic steroids abuse, and injection of mineral oil and oily veterinary compound containing vitamins A, D and E into muscles for local hypertrophy presented with hypercalcemia, nephrocalcinosis, and end-stage renal disease. On physical examination, the presence of calcified subcutaneous nodules and calcification of musculature previously infused with oily substances drew attention. Laboratory tests confirmed hypercalcemia of 12.62 mg/L, low levels of PTH (10 pg/mL), hyperphosphatemia (6.0 mg/dL), 25(OH)D of 23.3 ng/mL, and elevated 1,25(OH)2D (138 pg/mL). Imaging exams showed diffuse calcification of muscle tissue, subcutaneous tissue, and organs such as the heart, lung, and kidneys. The patient was diagnosed with PTH-independent hypercalcemia secondary to foreign body reaction in areas of oil injection. The patient underwent treatment with hydrocortisone for 10 days, single dose zoledronic acid and hemodialysis. He evolved with serum calcium levels of 10.4 mg/dL and phosphorus of 7.1 mg/dL. In addition, sertraline and quetiapine were prescribed to control body dysmorphic disorder. The medical community should become aware of new causes of hypercalcemia as secondary to oil injection since this should become increasingly frequent due to the regularity with which such procedures have been performed.

Severe hypercalcemia caused by repeated mineral oil injections: a case report.

Hypercalcemia is a frequent condition in clinical practice and when the most frequent causes are excluded, etiological diagnosis can be challenging. A rare cause of PTH-independent hypercalcemia is described in the present case report. A male adult with a history of androgenic-anabolic steroids abuse, and injection of mineral oil and oily veterinary compound containing vitamins A, D and E into muscles for local hypertrophy presented with hypercalcemia, nephrocalcinosis, and end-stage renal disease. On physical examination, the presence of calcified subcutaneous nodules and calcification of musculature previously infused with oily substances drew attention. Laboratory tests confirmed hypercalcemia of 12.62 mg/L, low levels of PTH (10 pg/mL), hyperphosphatemia (6.0 mg/dL), 25(OH)D of 23.3 ng/mL, and elevated 1,25(OH)2D (138 pg/mL). Imaging exams showed diffuse calcification of muscle tissue, subcutaneous tissue, and organs such as the heart, lung, and kidneys. The patient was diagnosed with PTH-independent hypercalcemia secondary to foreign body reaction in areas of oil injection. The patient underwent treatment with hydrocortisone for 10 days, single dose zoledronic acid and hemodialysis. He evolved with serum calcium levels of 10.4 mg/dL and phosphorus of 7.1 mg/dL. In addition, sertraline and quetiapine were prescribed to control body dysmorphic disorder. The medical community should become aware of new causes of hypercalcemia as secondary to oil injection since this should become increasingly frequent due to the regularity with which such procedures have been performed.

Impact of COVID-19 pandemic on prostate cancer outcomes at an uro-oncology referral center

ABSTRACT Introduction To evaluate the possible effects of the coronavirus disease 2019 (COVID-19) pandemic on the oncologic results of patients with prostate cancer regarding clinical staging, presence of adverse pathological outcomes, and perioperative complications. Materials and methods This retrospective study included patients who underwent radical prostatectomy. The time between biopsy and surgery, staging tests, final histopathological evaluation after surgery, lymphadenectomy rate, postoperative complications, and prostatic specific antigen (PSA) levels (initial and 30 days after surgery) were analyzed and compared in a group of patients before and during the pandemic period. Results We included 226 patients: 88 in the pre-pandemic period and 138 during the pandemic period. There was no statistically significant difference in mean age, body mass index, ASA, pathological locally advanced disease, the proportion of patients who underwent lymphadenectomy, and ISUP grade in the biopsy between the groups. Positive surgical margins, prostatic extracapsular extension, and PSA levels at 30 days were also similar between the groups. The mean time between medical consultation and surgery was longer in the pandemic period than in the pre-pandemic (124 vs. 107 days, p<0.001), and the mean time between biopsy and medical consultation (69.5 days vs. 114 days, p<0.001) and between biopsy and surgery (198.5 days vs. 228 days, p=0.013) was shorter during the pandemic. The incidence of severe early and late perioperative complications was similar between the periods. Conclusions There was no delay between diagnosis and treatment at our institution during the COVID-19 pandemic period. No worsening of the prostate cancer features was observed.

Impact of COVID-19 pandemic on prostate cancer outcomes at an uro-oncology referral center.

INTRODUCTION: To evaluate the possible effects of the coronavirus disease 2019 (COVID-19) pandemic on the oncologic results of patients with prostate cancer regarding clinical staging, presence of adverse pathological outcomes, and perioperative complications. MATERIALS AND METHODS: This retrospective study included patients who underwent radical prostatectomy. The time between biopsy and surgery, staging tests, final histopathological evaluation after surgery, lymphadenectomy rate, postoperative complications, and prostatic specific antigen (PSA) levels (initial and 30 days after surgery) were analyzed and compared in a group of patients before and during the pandemic period. RESULTS: We included 226 patients: 88 in the pre-pandemic period and 138 during the pandemic period. There was no statistically significant difference in mean age, body mass index, ASA, pathological locally advanced disease, the proportion of patients who underwent lymphadenectomy, and ISUP grade in the biopsy between the groups. Positive surgical margins, prostatic extracapsular extension, and PSA levels at 30 days were also similar between the groups. The mean time between medical consultation and surgery was longer in the pandemic period than in the pre-pandemic (124 vs. 107 days, p<0.001), and the mean time between biopsy and medical consultation (69.5 days vs. 114 days, p<0.001) and between biopsy and surgery (198.5 days vs. 228 days, p=0.013) was shorter during the pandemic. The incidence of severe early and late perioperative complications was similar between the periods. CONCLUSIONS: There was no delay between diagnosis and treatment at our institution during the COVID-19 pandemic period. No worsening of the prostate cancer features was observed.

Fatigue survival of endodontically treated teeth restored with different fiber-reinforced composite resin post strategies versus universal 2-piece fiber post system: An in vitro study.

STATEMENT OF PROBLEM: Various strategies have been proposed to reduce the cement space of foundation restorations for endodontically treated teeth. However, they may add more operative steps, or the dentist must keep different sizes of drills and posts in stock. A 2-piece universal adjustable post system has been developed to overcome this problem, but whether the system has acceptable fatigue survival performance is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the fatigue survival and stress distribution of endodontically treated teeth without a ferrule and restored with different glass fiber post strategies versus a recently introduced universal 2-piece fiber post system. MATERIAL AND METHODS: Bovine incisor roots were randomly assigned to 3 groups as per the post used (n=13): adapted glass fiber post with post space preparation of the same size, composite resin-custom glass fiber post (CTM), and universal 2-piece glass fiber-reinforced composite resin post (UNI). The posts were adhesively luted, the composite resin core was added, and a composite resin crown was produced with computer-aided design and computer-aided manufacturing (CAD-CAM), and then adhesively luted to each core. A fatigue test was performed with the stepwise stress method (10 000 cycles/step; 20 Hz; load=100 N to 750 N; step=50 N) until fracture, and the failure mode analyzed. The stress distribution was evaluated by finite element analysis with the maximum principal stress criteria by following the parameters of the in vitro test. The solids were considered homogeneous, linear, and isotropic, except for the glass fiber post (orthotropic), and a load of 450 N at 30 degrees was applied. The fatigue failure load and the number of cycles for failure were analyzed with Kaplan-Meier and Mantel-Cox (log rank test) (α=.05). The finite element analysis results were analyzed with colorimetric graphs. RESULTS: The highest fatigue failure load and the number of cycles for failure were found in the UNI system, whereas the lowest results were found in the CTM group. All groups exhibited repairable failures. The finite element analysis showed the lowest stress in root dentin in the UNI system. The CTM system had the largest stress regions at the dentin and dentin-core interface. CONCLUSIONS: The use of a 2-piece universal glass fiber post system resulted in more fatigue behavior compared with composite resin-custom glass fiber posts.

Resin cement coating reverts the machining damage on the flexural fatigue strength of lithium disilicate glass-ceramic.

This study evaluated the effect of resin cement coating with high and low viscosities on the flexural fatigue strength of machined lithium disilicate glass-ceramic. Discs (IPS e.max CAD; Ivoclar Vivadent) were prepared and divided according to the surface condition (machining [M]-CEREC inLab; and polishing [P]-laboratory procedures), resin cement coating (with or without), and cement viscosity (high [H] and low [L]). The ceramic bonding surface was etched/primed by a one-step primer application followed by resin cement application (Variolink N base + high or low viscosity catalyst; Ivoclar Vivadent). Biaxial flexural fatigue strength was evaluated on a piston-on-three-ball set by the step-test method (n = 15) (initial stress: 60 MPa; incremental steps: 20 MPa; 10,000 cycles/step, at 20 Hz). Weibull statistics were used for fatigue data. Contact angle, topographic, and fractographic analysis were also performed. Machining produced statistically lower contact angle than polishing and a significant detrimental effect on the fatigue behavior (σ0 M = 247.2 [246.9-268.3]; σ0 P = 337.4 [297.8-382.4]). Machined groups followed by resin cement coating (σ0 MH = 297.9 [276.0-321.5]; σ0 Ml = 301.2 [277.1-327.4]) behaved similarly to the polished and coated groups (σ0 PH = 342.0 [308.9-378.5]; σ0 PL = 357.3 [324.7-393.1]), irrespective of the cement viscosity. Therefore, cement coating has able to revert the detrimental effects of the machining on the fatigue strength of lithium disilicate glass-ceramic. High and low viscosity cements behaved similarly in the improvement of CAD-CAM lithium disilicate fatigue strength.

Biomechanics of implant-supported restorations / Biomecânica das restaurações implantossuportadas

The rehabilitation of patients with dental implant-supported restorations is an ideal treatment option in contemporary dentistry. The aim of this review was to compile and to demonstrate the mechanical response during loading condition, on the stress distributions of implant-supported prostheses. The findings show that the majority of stresses were concentrated in the cervical region of the implant/abutment interface and that they can be affected by several clinical parameters and loading conditions. Finally, the final prosthetic design should combine superior mechanical response, long-term survival rate and allow patient satisfaction. (AU)

A reabilitação de pacientes com restaurações implanto-suportadas é uma opção de tratamento ideal na odontologia contemporânea. O objetivo desta revisão foi compilar e demonstrar a resposta mecânica durante a aplicação de carga, na distribuição de tensão de próteses implanto-suportadas. Os achados mostram que a maioria das tensões se concentram na região cervical da interface implante/pilar e pode ser afetada por diversos parâmetros clínicos e condições de carregamento. Por fim, o desenho protético final deve combinar uma melhor resposta mecânica, taxa de sobrevida a longo prazo e permitir a satisfação do paciente. (AU)

Substrate Rigidity Effect on CAD/CAM Restorations at Different Thicknesses.

OBJECTIVES: This article evaluated the effect of substrates rigidities on the post-fatigue fracture resistance of adhesively cemented simplified restorations in lithium disilicate glass ceramic. METHODS: Precrystalized computer-aided design/computer-aided manufacturing ceramic blocks were processed into disc-shaped specimens (n = 10, Ø = 10 mm), mimicking a simplified restoration at two thicknesses (0.5 and 1.0 mm). Thereafter, the discs were cemented onto different base substrates (dentin analogue [control], dentin analogue with a central core build-up of resin composite [RC], or glass ionomer cement [GIC]). The specimens were subjected to mechanical cycling in a chewing simulator (100 N, 1 × 106 cycles, 4 Hz) and then subjected to thermocycling aging (10,000 cycles, 5/37/55°C, 30 seconds). After the fatigue protocol, the specimens were loaded until failure (N) in a universal testing machine. Finite element analysis calculated the first principal stress at the center of the adhesive interface. RESULTS: The results showed that "restoration thickness," "type of substrate," and their interaction were statistically significant (one-way analysis of variance; p < 0.001). Regardless the restoration thickness a higher fracture load was observed for specimens cemented to dentin analogue. Among the base materials, RC build-up presented the highest fracture load and lower stress magnitude for both restoration thicknesses in comparison with GIC build-up. The 0.5-mm restoration showed higher stress peak and lower fracture load when submitted to the compressive test. CONCLUSION: More flexible base material reduces the fracture load and increases the stress magnitude of adhesively cemented lithium disilicate restorations regardless the ceramic thickness. Therefore, more rigid substrates are suggested to be used to prevent restoration mechanical failures.

Impact of the Temperature in Endophytic Ascomycota Isolated from Antarctic Hair-Grass.

Antarctica is one of the most inhospitable continents on the planet, with lichens and mosses being the most common terrestrial organisms in ice-free areas. Antarctica is represented by only two species of Angiosperms, Deschampsia antarctica Desv. (Poaceae) and Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae). In this study, we characterized fungi isolated from the fresh leaves of this grass species. The fungi were isolated from four individual plants from Half Moon Island (246 leaf fragments investigated), and seven from King George Island-Keller Peninsula (with 111 leaf fragments investigated) Antarctica. Neoascochyta paspali, Septoriella elongata, Pyrenophora cf. chaetomioides and Alternaria sp. were associated with the plant and identified through analysis of the sequences of the internal transcribed spacer region (ITS) of the rDNA and nuclear ribosomal large subunit rRNA gene (LSU) as well as through macro and micro-morphological characteristics. The isolates showed higher growth rate ranging from 10 to 20 °C. An interesting result was that the aforementioned fungi are already recognized as both plant pathogens and endophytic fungi. The results demonstrate that D. antarctica is an interesting fungal source. Those species might provide important information about the relationship on the endemic Antarctic biota.