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The present study evaluated the mechanical behavior of five designs of Morse taper (MT) connections with and without the application of loads. For this, the detorque of the fixing screw and the traction force required to disconnect the abutment from the implant were assessed. A total of 100 sets of implants/abutments (IAs) with MT-type connections were used, comprising five groups (n = 20/group): (1) Group Imp 11.5: IA sets with a cone angulation of 11.5°; (2) Group SIN 11.5: with a cone angulation of 11.5°; (3) Group SIN 16: with a cone angulation of 16°; (4) Group Neo 16: with a cone angulation of 16°; and (5) Group Str 15: with a cone angulation of 15°. All sets received the torque recommended by the manufacturer. After applying the torque, the counter torque of the fixing screws was measured in ten IA sets of each group without the application of cyclic loads (frequencies ≤ 2 Hz, 360,000 cycles, and force at 150 Ncm). The other ten sets of each group were subjected to cyclic loads, after which the detorque was measured. Afterwards, the force for disconnection between the implant and the abutment was measured by traction on all the samples. The untwisting of the abutment fixation screws showed a decrease in relation to the initial torque applied in all groups. In the unloaded samples, it was found to be -25.7% in Group 1, -30.4% in Group 2, -36.8% in Group 3, -29.6% in Group 4, and -25.7% in Group 5. After the applied loads, it was found to be -44% in Group 1, -43.5% in Group 2, -48.5% in Group 3, -47.2% in Group 4, and -49.8% in Group 5. The values for the IA sets were zero for SIN 16 (Group 3) and Neo16 (Group 4), both without and with loads. In the other three groups, without loads, the disconnection value was 56.3 ± 2.21 N (Group 1), 30.7 ± 2.00 N (Group 2), and 26.0 ± 2.52 N (Group 5). After applying loads, the values were 63.5 ± 3.06 N for Group 1, 34.2 ± 2.45 N in Group 2, and 23.1 ± 1.29 N in Group 5. It was concluded that in terms of the mechanical behavior of the five designs of MT IA sets, with and without the application of loads, the Imp 11.5, SIN 11.5, and Srt 15 groups showed better results compared to the SIN 16 and Neo 16 groups, showing that lower values of cone angulation increase the friction between the parts (IA), thus avoiding the need to maintain the torque of the fixing screw to maintain the union of the sets.

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This study evaluated the clinical survival rates of 170 Morse taper implants through clinical and mechanical parameters in different therapeutic approaches such as single crowns, fixed partial prostheses, and fixed full-arch prostheses. Patients referred to the Center on Education and Research on Dental Implants from May 2017 to July 2018 with the indication for dental implant therapy, aged >18 years, without periodontal disease, recent evidence of inflammatory activity or other oral disorders, current pregnancy, uncontrolled diabetes mellitus or heavy smoking habit were included in this study. After 12 weeks of healing since the implants were placed in the mandible and after 16 weeks following implants placed in the maxilla, patients returned to the Center for prosthetic rehabilitation. After implant therapy, all patients underwent periodical, clinical, and prosthetic examinations every 6 months. Prosthetic restorations involved 109 fixed reconstructions in function. Few prosthetic complications were reported (6.55%). Twenty implants were rehabilitated with cemented prostheses; from those, 1 crown suffered a loss in retention/decementation. Of the 148 implants rehabilitated with screwed-retained prostheses, 6.76% suffered prosthetic screw loosening. The cumulative implant survival rate was 98.2%. When peri-implant tissue health was evaluated, the keratinized mucosa band appeared related to peri-implant tissue stability. Thus, Morse taper implants represented a successful procedure for implant rehabilitation, with a high cumulative implant survival rate, low prevalence of biological and prosthetic complications, and good stability of peri-implant tissues over the assessed period.

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Objective: The primary objective of the present retrospective clinical study was to evaluate and compare the clinical performance presented by castable abutments developed for the MT system versus intermediate machined abutments, specifically regarding prosthetic or implant fractures/loss; the secondary objective was to verify the looseness of the abutments and the behavior of the peri-implant soft tissues. Methods: This clinical retrospective study was conducted on patients rehabilitated between 2019 and 2020. Inclusion criteria were patients in good general health, with an implants-supporting single crown; with solid machined abutments (control group) or castable UCLA abutments; with a connection portion (base) machined in cobalt-chrome (test group) over Morse taper DuoCone implants in the posterior mandible area; and at least two years in function. Clinical assessment was carried out by the same professional, considering the following parameters: (A) prosthetic: (i) loosening of the fixation screw, (ii) fracture of the screw and (iii) the number of times the patient had some type of complication after the installation of the prostheses were evaluated; (B) biological: (i) without keratinized mucosa (KM), (ii) 1 mm or less, (iii) between 1 and 2 mm and (iv) greater than 2 mm of KM width; and the presence or absence of mucositis. Furthermore, radiographic evaluation was performed in order to assess the marginal bone loss. These evaluations permitted to compare the groups analyzed and patients enrolled. Data were statistically analyzed, with the level of significance set at α = 0.05. Results: 79 patients with 120 MT implants were evaluated (80 castable UCLA abutments and 40 machined solid abutments). The follow-up was from 2 to 4 years. There was a 100% implant survival rate. Therefore, the control group showed two fractured abutments (5%) and no abutment loosening (95% for prosthetic survival rate), whereas the test group showed no abutment fracture but nine loosening screws (11.3%) (100% for prosthetic survival rate). Keratinized mucosa was considered thin or absent in 19 implants in the control group (47.5%) and 42 in the test group (52.5%). Mucositis was found in 11 implants in the control group (27.5%) and 27 in the test group (33.8%). A positive correlation was observed between the width of keratinized mucosa and mucositis (r = 0.521, p = 0.002). The mean marginal bone loss was 2.3 mm, ranging from 1.1 to 5.8 mm. No correlation was observed when considering marginal bone loss versus the three parameters (implant diameter, implant length and time of the prosthesis in function). Conclusions: The results suggest that UCLA-type abutments are a viable option for rehabilitating implants with Morse taper connections, suggesting lower fracture risk. Further research is necessary to confirm these findings and thoroughly evaluate the clinical performance and long-term outcomes.

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BACKGROUND: Adverse local tissue reaction (ALTR) is a recognized complication of total hip arthroplasty (THA) with metal-on-polyethylene (MoP) bearing surface implants. Specific models of THA implants have been identified as having a higher incidence of ALTR. The purpose of this study is to determine if serum metal levels, patient symptoms, implant factors, and imaging findings can be predictive of ALTR within this high-risk population. METHODS: We retrospectively reviewed an observational cohort of 474 patients who underwent MoP THA and were at increased risk of having ALTR. Patients were stratified based on the presence or absence of ALTR. Patient symptoms, serum metal ions, implant head offset, and imaging findings were compared. RESULTS: Patients with ALTR were more likely to be symptomatic (52.9% vs 9.9%, P < .0001). The presence of ALTR was associated with significantly higher serum cobalt and chromium levels (6.2 ppb vs 3.6 ppb, P < .0001; 2.3 ppb vs 1.2 ppb, P < .0001). Head offsets greater than 4 mm were associated with a higher prevalence of ALTR (53% vs 38%, P = .05). On metal artifact reduction sequence magnetic resonance imaging, patients with ALTR had larger effusions (4.7 cm vs 2.1 cm, P < .001) and a higher incidence of trochanteric bursitis (47% vs 16%, P < .001). CONCLUSIONS: In high-risk MoP implants, serum cobalt and chromium levels are elevated, even in patients without ALTR. A larger femoral head offset is a risk factor for the development of ALTR. Our study suggests that patients presenting with painful THA and elevated metal ions require risk stratification based on patient symptoms, metal artifact reduction sequence magnetic resonance imaging findings, and implant factors.

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Total hip arthroplasty, one of the most successful orthopaedic procedures, is influenced by several variables. Corrosion at the modular junction is known as trunnionosis. Despite being reported infrequently, corrosion between the femoral head and the Morse taper can result in severe complications. Fracture of the femoral component in primary metal-on-metal (MoM) total hip arthroplasty at the Morse taper is an extremely rare event and can be associated with several risk factors. We report a case of corrosion at the Morse taper in a hybrid primary MoM total hip arthroplasty, resulting in Morse taper fracture with consequent femoral head entrapment inside the acetabular component. We hypothesise that some risk factors, such as age over 60years, active male patients, body mass index above 30kg/m2, large femoral heads, high-offset stems, 9/10 Morse taper and MoM-bearing surfaces, are associated with this mode of failure.

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O conceito de Endodontia Minimamente Invasiva é amplo, e envolve não só a realização de acessos, mas também o uso de instrumentos com conicidades reduzidas ou geometrias inovadoras. Buscando avaliar se as estratégias minimamente invasivas adotadas apresentam vantagens frente aos tratamentos tradicionais, a presente tese foi dividida em três estudos. O estudo 1 avaliou a preservação da dentina perirradicular e o alargamento da porção apical dos canais de molares inferiores com instrumentos TruNatomy e ProTaper Gold. Para isso, vinte molares inferiores foram microtomografados, pareados e distribuídos em 2 grupos. No grupo ProTaper Gold, os canais mesial e distal foram preparados até os instrumentos F2 e F3, respectivamente, enquanto no grupo TruNatomy, os canais mesial e distal foram ampliados até os instrumentos prime e medium, respectivamente. Após um novo escaneamento, os parâmetros de instrumentação foram calculados. Os dados foram analisados pelos testes de Mann-Whitney, T Student e escalonamento multidimensional não-métrico. Não foram encontradas diferenças entre os grupos em relação à área não preparada e redução de espessura de dentina. O grupo ProTaper Gold removeu mais dentina que o TruNatomy no terço coronal das raízes mesiais. O estudo 2 avaliou a formação de microtrincas dentinárias em molares inferiores acessados de forma ultraconservadora (UltraAC), instrumentados com Reciproc e XP-Endo Shaper. Quarenta molares inferiores foram microtomografados, pareados e distribuídos em 4 grupos de acordo com o tipo de cavidade de acesso e protocolo do sistema de instrumentação: tradicional/Reciproc; tradicional/XP-endo Shaper; UltraAC/Reciproc e UltraAC/XP-endo Shaper. Após os preparos dos canais, os dentes foram escaneados novamente e as imagens transversais das raízes mesiais e distais, do nível da furca ao ápice foram avaliadas com o objetivo de identificar a presença de microtrincas dentinárias. Em todos os grupos, as microtrincas verificadas nas imagens pós-operatórias já estavam presentes no exame pré-operatório. O estudo 3 avaliou a influência de instrumentos com o mesmo diâmetro de ponta e diferentes conicidades no percentual de área não preparada e volume de dentina removida após o preparo dos canais mesiovestibular e distovestibular de molares superiores com ou sem o canal mesiovestibular 2 (MV2). Vinte e dois molares superiores foram selecionados, microtomografados, pareados e classificados em dois grupos, de acordo com a anatomia das raízes: dentes com MV2 e dentes sem MV2. Após o acesso, os canais radiculares foram preparados com instrumentos 25/.01, 25/.03, 25/.05, 25/.06 e 25/.08v. Os dentes foram submetidos a novos escaneamentos por micro-CT após preparo com cada instrumento descrito anteriormente. Os dados foram analisados usando o Modelo linear generalizado misto e aproximação de Kenward-Roger para testes Wald F. Em dentes com e sem canais MV2, a porcentagem de área não preparada apresentou uma diminuição significativa ao longo do tratamento após cada instrumento utilizado e a porcentagem de dentina removida apresentou um aumento significativo ao longo do tratamento. Com base nos estudos, concluiu-se que as estratégias minimamente invasivas adotadas não apresentaram vantagens frente aos tratamentos tradicionais(AU)

The concept of Minimally Invasive Endodontics is broad, and involves not only the realization of accesses, but also the use of instruments with reduced tapers or innovative geometries. Seeking to assess whether the minimally invasive strategies adopted have advantages over traditional treatments, this thesis was divided into three studies. Study 1 evaluated the preservation of periradicular dentin and enlargement of the apical portion of the mandibular molar canals prepared with TruNatomy and ProTaper Gold instruments. For this, twenty lower molars were microtomography, paired and divided into 2 groups. In the ProTaper Gold group, the mesial and distal canals were prepared up to the F2 and F3 instruments, respectively, while in the TruNatomy group, the mesial and distal canals were prepared up to the prime and medium instruments, respectively. After a new scan, the instrumentation parameters were calculated. Data were analyzed by Mann-Whitney, T Student and non-metric multidimensional scaling tests. No differences were found between groups regarding unprepared area and dentin thickness reduction. The ProTaper Gold group removed more dentin than TruNatomy in the coronal third of the mesial roots. Study 2 evaluated the formation of dentinal microcracks in mandibular molars accessed by ultraconservative cavites (UltraAC), instrumented with Reciproc and XP-Endo Shaper. Forty lower molars were microtomography, paired and divided into 4 groups according to the type of access cavity and instrumentation system protocol: traditional/Reciproc; traditional/XP-endo Shaper; UltraAC/Reciproc and UltraAC/XP-endo Shaper. After the root canal preparations, the teeth were scanned again and the transverse images of the mesial and distal roots, from the furcation level to the apex, were evaluated in order to identify the presence of dentinal microcracks. In all groups, the microcracks seen in the postoperative images were already present in the preoperative examination. Study 3 evaluated the influence of instruments with the same tip diameter and different tapers on the percentage of unprepared area and volume of dentin removed after preparation of the mesiobuccal and distobuccal canals of maxillary molars with or without the mesiobuccal canal 2 (MV2). Twenty-two maxillary molars were selected, microtomography, paired and classified into two groups, according to root anatomy: teeth with MV2 and teeth without MV2. After access, the root canals were prepared with instruments 25/.01, 25/.03, 25/.05, 25/.06 and 25/.08v. The teeth were rescanned by micro-CT after preparation with each instrument described above. Data were analyzed using the Generalized Linear Mixed Model and Kenward-Roger approximation for Wald F tests. In teeth with and without MV2 canals, the percentage of unprepared area showed a significant decrease throughout the treatment after each instrument used and the percentage of removed dentin showed a significant increase during treatment. Based on the studies, it was concluded that the minimally invasive strategies adopted did not present advantages over traditional treatments(AU)

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The gap formed at the abutment-implant interface brings about a bacterial colonization. In addition, a bacterial reservoir can be established within the implant. The build-up of microorganisms around the implant can cause soft tissue infections and bone loss around the implant, which can lead to implant failure. Our literature review aimed to evaluate the infiltration at the implant-abutment interface, comparing the Morse cone connection with the external hexagon and internal hexagon connections. A literature search using the PubMed database was performed on March 24, 2021. The search terms were combinations of "Morse cone" or "Morse taper" with each of the following terms (individually): "microleakage", "leakage", "infiltration", and "penetration". The inclusion criterion was in vitro studies comparing the Morse cone with the external hexagon and/or internal hexagon, based on infiltration at the implant-abutment interface. The exclusion criterion was the evaluation of microleakage at the implant-abutment interface after applying a sealant over this region. The search was expanded as needed. There was no limit on the year of publication, and only articles written in English were included. In addition, references cited in included articles were also included in this review when they were appropriate. This literature review concluded that, in most cases, the microleakage in the Morse cone connection was lower when compared with the external hexagon and internal hexagon connections.

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BACKGROUND: Diagnosis of adverse local tissue reaction (ALTR) in metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper corrosion is challenging. The purpose of this study is to compare differences between asymptomatic and symptomatic ALTR in an observational cohort, including presentation, metal ion differences, and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) findings. METHODS: We performed a retrospective review of an observational cohort of 492 MoP THA patients at increased risk of developing ALTR. Ninety-four patients underwent revision arthroplasty for ALTR. Patients were stratified into symptomatic and asymptomatic ALTR groups. Presentation, metal ion levels, and imaging findings were compared. RESULTS: For patients with confirmed ALTR, 41% were asymptomatic. There was a statistically significant difference in the serum chromium levels between symptomatic and asymptomatic ALTR patients (2.2 µg/L vs 3.1 µg/L, P = .05). There was no statistically significant difference between the serum cobalt levels or MRI findings in these 2 groups. We observed that extracapsular disease associated with ALTR could be misinterpreted as trochanteric bursitis. CONCLUSION: Almost half of the MoP THA ALTR cases identified were asymptomatic. Cobalt levels could not differentiate between symptomatic and asymptomatic pseudotumor formation. Symptomatic and asymptomatic MoP ALTRs have similar MARS MRI characteristics. Our findings suggest that it is essential to risk stratify patients who could potentially have ALTR based on implant type, symptoms, ion levels, and MARS MRI.

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In the stems of terrestrial vascular plants studied to date, the diameter of xylem water-conducting conduits D widens predictably with distance from the stem tip L approximating D âˆ Lb , with b ≈ 0.2. Because conduit diameter is central for conductance, it is essential to understand the cause of this remarkably pervasive pattern. We give reason to suspect that tip-to-base conduit widening is an adaptation, favored by natural selection because widening helps minimize the increase in hydraulic resistance that would otherwise occur as an individual stem grows longer and conductive path length increases. Evidence consistent with adaptation includes optimality models that predict the 0.2 exponent. The fact that this prediction can be made with a simple model of a single capillary, omitting much biological detail, itself makes numerous important predictions, e.g. that pit resistance must scale isometrically with conduit resistance. The idea that tip-to-base conduit widening has a nonadaptive cause, with temperature, drought, or turgor limiting the conduit diameters that plants are able to produce, is less consistent with the data than an adaptive explanation. We identify empirical priorities for testing the cause of tip-to-base conduit widening and underscore the need to study plant hydraulic systems leaf to root as integrated wholes.

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As cavidades de acesso dominaram a recente discussão sobre a Endodontia minimamente invasiva (EMI). No entanto, a rotulagem da EMI é mais ampla, envolvendo o uso de instrumentos com conicidades reduzidas ou geometrias inovadoras que permitam a remoção mínima de dentina. Além disso, aprimoramentos metodológicos têm sido sugeridos para mimetizar condições clínicas. Buscando responder algumas questões acerca da EMI, a presente tese é dividida em dois estudos. O estudo 1 avaliou a influência do acesso ultraconservador (UltraAC) na instrumentação, na qualidade da obturação e na capacidade máxima de carga para fratura em molares inferiores após o preparo do canal com o sistema XP-endo Shaper (XP) ou Reciproc (RC) em condições clínicas simuladas. Para isso, quarenta molares inferiores foram microtomografados e pareados em quatro grupos (n = 10), de acordo com o acesso e a instrumentação: TradAC/RC, TradAC/XP, UltraAC/RC e UltraAC/XP. Os dentes foram reescaneados e os parâmetros da instrumentação e obturação foram analisados. Os dentes foram restaurados e submetidos à ciclagem termomecânica e à capacidade máxima de carga para a fratura. O teste ANOVA foi usado para a análise estatística (P < 0,05). Os grupos TradAC apresentaram menor porcentagem (%) de área não preparada do que os grupos UltraAC (P < 0,05). O grupo UltraAC/XP apresentou a menor % de dentina removida (P < 0,05). A % de debris foi menor nos grupos UltraAC/XP e TradAC/XP do que no UltraAC/RC e TradAC/RC (P < 0,05). Os grupos UltraAC demonstraram maior % de espaços vazios e de material obturador na câmara pulpar (P < 0,05). Não houve diferença na capacidade máxima de carga para a fratura entre os grupos (P > 0,05). O estudo 2 avaliou o uso de instrumentos com conicidade reduzida - Bassi Logic ,03 (BL), com diferentes designs (XP) e como grupo de comparação o sistem Reciproc, na eficácia da instrumentação dos canais em condições clínicas simuladas. Vinte e quatro molares foram microtomografados, acessados de forma tradicional e divididos em três grupos (n = 8), de acordo com o preparo: BL, XP e RC. Nos grupos BL e RC, os canais mesiais foram instrumentados com 25/,03 ou R25 e o canal distal com 25/,03 e 40/,03 ou R25 e R40, respectivamente. No grupo XP, o mesmo instrumento foi utilizado em todos os canais (30/,04). Após o preparo, os dentes foram reescaneados e a % de área não preparada e de dentina removida foram avaliadas separadamente para os canais mesiais e distal. Os dados foram analisados com os testes ANOVA e de Tukey (P < 0,05). Verificou-se que o grupo BL apresentou maior % de área não preparada para ambos os canais em relação aos grupos XP e RC (P < 0,05). No entanto, não houve diferença na % de dentina removida entre os grupos (P > 0,05). Com base nos estudos, conclui-se que as estratégias minimamente invasivas adotadas no acesso e na instrumentação foram desvantajosas frente a tratamentos tradicionais, não justificando o seu uso(AU)

Access cavities have dominated the recent discussion on minimally invasive Endodontics (EMI). However, the issue of MIE is broader than access cavities, such as the use of instruments with reduced taper or innovative geometries that allow minimal dentin removal. Furthermore, methodological improvements have been suggested to mimic clinical conditions. Seeking to answer some questions about EMI, this thesis is divided into two studies. The first study evaluated the influence of ultraconservative access (UltraAC) on canal shaping, filling ability and maximum load capacity for fracture of mandibular molars after root canal preparation with XP-endo Shaper (XP) or Reciproc (RC), under simulated clinical conditions. Thus, forty mandibular molars were scanned and paired into four groups (n = 10), according to access and instrumentation protocol: TradAC/RC, TradAC/XP, UltraAC/RC and UltraAC/XP. Teeth were rescanned and the instrumentation and filling parameters were analyzed. The teeth were restored and submitted to thermomechanical cycling and maximum load capacity for the fracture. ANOVA test was used for statistical analysis (P < 0.05). The TradAC groups had a lower percentage (%) of unprepared area than the UltraAC groups (P < 0.05). The UltraAC/XP group had the lowest % of dentin removed (P < 0.05). The % of debris was lower in the UltraAC/XP and TradAC/XP groups than in the UltraAC/RC and TradAC/RC groups (P < 0.05). The highest % of voids and filling material in the pulp chamber was observed in the UltraAC groups (P < 0.05). There was no difference in the maximum load capacity for the fracture between the groups (P > 0.05). The second study evaluated the use of a reduced taper endodontic instrument system - Bassi Logic .03 taper (BL), expandable heat-treated system (XP) and, as comparison, the Reciproc system, on the ability to shape canals under simulated clinical conditions. For that, twenty-four mandibular molars were scanned and divided into three groups (n = 8), according to root canal instrumentation system: BL, XP and RC. In the BL and RC groups, the mesial canals were instrumented with 25/.03 or R25 and the distal canal with 25/.03 and 40/.03 or R25 and R40, respectively. In the XP group, the same instrument was used in all root canals (30/.04). After preparation, the teeth were rescanned and the % of unprepared area and dentin removed were evaluated separately for the mesial and distal canals. Data were analyzed using ANOVA and Tukey tests (P < 0.05). It was found that the BL group had a higher % of unprepared area for both root canals compared to the XP and RC groups (P < 0.05). However, there was no difference in the % of dentin removed between groups (P > 0.05). Based on the studies, it is concluded that there is no justification for the use of EMI since in general, UltraAC did not promote advantages over TradAC and the use of instruments with reduced taper resulted in a larger unprepared area, which could possibly influence the cleaning of the root canal system (AU)

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AIM: To evaluate the use of a reduced taper endodontic instrument system (Bassi Logic™ .03 taper) and expandable heat-treated system (XP-endo Shaper) on the ability to shape canals in mandibular molars, by means of microcomputed tomography (micro-CT) analysis. The Reciproc system was used as the reference for comparison. METHODOLOGY: Twenty-four mandibular molars were scanned in a micro-CT, matched based on similar anatomical features and sorted into three groups (n = 8 per group), according to root canal preparation system: Bassi Logic™ .03, XP-endo Shaper and Reciproc. The teeth were mounted onto a mannequin and the pulp chambers were accessed with traditional access cavities. In Bassi Logic™ .03 and Reciproc groups, mesial canals were prepared with size 25, .03 taper or R25 (size 25, .08v taper) instruments and the distal root canal with size 25, .03 taper and size 40, .03 taper or R25 and R40 (size 40, .06v taper), respectively. In XP-endo Shaper groups, all root canals were prepared with XP-endo Shaper (size 30, .04v taper). After root canal preparation, the teeth were rescanned. The percentage of untouched canal areas and the percentage of removed dentine were evaluated separately for mesial and distal root canals. The data were analysed using one-way anova and Tukey tests (P < 0.05). RESULTS: The Bassi Logic™ .03 group was associated with a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc groups for mesial and distal root canals (P < 0.05), but no differences were found between XP-endo Shaper and Reciproc groups (P > 0.05). No significant difference was observed in the percentage of dentine removed amongst the groups for mesial and distal root canals (P > 0.05). CONCLUSION: The use of a reduced taper system (Bassi Logic™ .03) during root canal preparation resulted in a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc instruments. No differences were observed amongst the systems regarding the percentage of dentine removed.

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Objetivo: Evaluar radiográficamente 162 tratamientos endodónticos realizados ex vivo en premolares inferiores y superiores humanos mediante el empleo del sistema ProTaper Next por parte de alumnos de grado de una cátedra de endodoncia de una universidad argentina. Materiales y métodos: Se evaluaron 162 tratamientos endodónticos realizados ex vivo durante los años 2017, 2018 y 2019 (54 por cohorte) en premolares inferiores y superiores humanos por alumnos de grado de la cátedra de Endodoncia I de la Escuela de Odontología de la Universidad del Salvador / Asociación Odontológica Argentina. Para la instrumentación fue empleado el sistema ProTaper Next. La muestra se tomó de forma aleatoria. En un programa de presentación de computadora se incluyeron las radiografías periapicales pre- y posoperatoria para su evaluación. Un evaluador externo analizó las imágenes radiográficas de los tratamientos y los categorizó como correctos o incorrectos teniendo en cuenta tres requisitos excluyentes: la conformación de la preparación quirúrgica, el límite apical y la homogeneidad de la obturación. Para el análisis estadístico, se utilizó la frecuencia relativa (intervalo de confianza 95%) y la prueba de chi-cuadrado. Resultados: La evaluación radiográfica de los tratamientos endodónticos realizados mostró un número considerable de tratamientos correctos. Los resultados para cada cohorte (años 2017, 2018 y 2019) fueron del 96,3% (87,2- 99,5%), el 94,4% (84,6-98,8%) y el 98,2% (90,1-99,9%) respectivamente. El porcentaje global de tratamientos correctos fue del 96,3% (92,1-98,6%). La diferencia entre las cohortes no fue estadísticamente significativa (P>0,05). Conclusión: El empleo del sistema ProTaper Next por parte de estudiantes de grado evaluados mostró resultados radiográficamente satisfactorios en la instrumentación ex vivo de conductos radiculares de premolares inferiores y superiores humanos (AU)

Aim: To evaluate radiographically, 162 endodontic treatments performed ex vivo by three cohorts of students from a school of dentistry in Argentina, using ProTaper Next rotatory system in mandibular and maxillary human premolars. Materials and methods: 162 mandibular and maxillary human premolars received endodontic treatment by undergraduate students from the Department of Endodontics I of the School of Dentistry USAL/AOA. The treatments were performed ex vivo during the academic years 2017, 2018 and 2019 (54 teeth were chosen for each cohort) using the rotatory system ProTaper Next. The samples were taken randomly. Pre and postoperative radiographs were included in a computer presentation program for its evaluation. An external examiner analysed the radiographic images by the shape of the preparation, the apical limit, and the homogeneity of the obturation, considering the treatments well obturated (correct) or ill obturated (incorrect). To be considered correct the case had to meet all the requirements. The statistic calculations used in this study were: relative frequency (confidence interval 95%) and the chi-square test. Results: The radiographic evaluation showed a considerable number of endodontic treatments correctly done using ProTaper Next system. The percentages for each cohort were 96.3% (87.2-99.5%), 94.4% (84.6-98.8%) y 98.2% (90.1-99.9%) for years 2017, 2018 y 2019 respectively. Global percentage of correctly endodontic treatments was 96.3% (92.1-98.6%). The difference between the cohorts was not statistically significant (P>0.05). Conclusion: The use of ProTaper Next by the dental students evaluated showed satisfactory results in the ex vivo instrumentation of mandibular and maxillary human premolar root canals (AU)

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Antecedentes: Las limas rotatorias de níquel-titanio con tratamiento termomecánico se desarrollaron para permitir una mayor flexibilidad al instrumentar los conductos radiculares. Los instrumentos permitieron a los operadores tratar las curvaturas de los conductos con mayor facilidad. Los fabricantes están tratando de producir limas que funcionen de manera más eficiente y segura. Conocer las propiedades de las limas comercializadas es especialmente importante porque ayuda a elegir un sistema de lima apropiado. El objetivo de este estudio fue evaluar la flexibilidad de tres limas diferentes de níquel-titanio (NiTi) con tratamiento termomecánico en dos puntos diferentes. Materiales y métodos: Se midió la flexibilidad de tres limas NiTi con tratamiento termomecánico (ProTaper Gold, 2Shape y V-Taper Fanta Gold). Cada lima fue sujetada a 3 mm y 7 mm (n = 10/longitud/lima) y se utilizó una máquina de ensayo universal para doblarla a una fuerza máxima. Todos los datos fueron analizados estadísticamente por análisis de varianza de una vía y prueba de Tukey post hoc (p = 0,05) para determinar cualquier diferencia significativa. Resultados: Se halló diferencias estadísticamente significativas (p < 0,05). En general, V-Taper Fanta Gold fue la más rígida, ProTaper Gold mostró los mayores valores de fuerza y su deformación fue significativamente más flexible. Conclusión: Las limas ProTaper Gold mostraron una mayor flexibilidad en comparación con las otras limas estudiadas. (AU)

Background: Nickel-titanium rotary files with thermomechanical treatment were developed to allow greater flexibility when instrumenting the root canals. The instruments allowed operators to deal with duct curvatures more easily. Manufacturers are trying to produce files that work better efficiently and safely. Knowing the properties of marketed files is especially important in helping you choose an appropriate file system. The objective of this study was to evaluate the flexibility of three different nickel-titanium (NiTi) files with thermomechanical treatment at two different points along the file. Materials and methods: The flexibility of three NiTi files with thermomechanical treatment (Protaper Gold, 2Shape and V-Taper Fanta Gold) was measured. Each file was clamped at 3 mm and 7 mm (n = 10 / length / file) and a universal testing machine was used to bend the files to a maximum strength. All data were statistically analyzed by one-way analysis of variance and post-hoc Tukey test (P = 0.05) to determine any significant differences. Results: There were statistically significant differences (P <0.05). In general, V-Taper Fanta Gold was the most rigid, Protaper Gold showed the highest values of force and deformation was significantly more flexible. Conclusión: Protaper Gold files showed greater flexibility compared to the other files studied. (AU)

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AIM: To evaluate the influence of ultraconservative endodontic access cavities (UEC) and the use of instruments with various tapers (.03 or .05) and tip diameters (25 or 40) on the ability to shape canals in mandibular molars and their fracture resistance in comparison with traditional endodontic access cavities (TEC). METHODOLOGY: Thirty-two intact extracted mandibular molars were scanned in a micro-computed tomography device, matched based on similar anatomical features and assigned to UEC or TEC groups and to subgroups according to mechanical canal preparation with Bassi Logic™ rotary NiTi instruments with .03 or .05 taper (n = 8 per group). The teeth were mounted onto a mannequin head, and the pulp chambers were accessed and the root canals subjected to instrumentation. In the first stage, size 25 endodontic instruments were used, with .03 or .05 tapers. The teeth were re-scanned. Subsequently, a second canal instrumentation was performed with the size 40 instruments with .03 or .05 tapers and scanned again. The root canals were filled and then the teeth restored before being subjected to fracture resistance tests. The data on untouched canal areas, canal transportation, centring ability, the percentage of removed dentine and maximum load at fracture were analysed. One-way anova and Tukey's tests were performed for inter-group analysis. The paired-samples t-test was performed on the results between size 25 and size 40 apical preparations for each individual specimen (P < 0.05). RESULTS: No significant difference was observed for the percentage of untouched canal area when comparing UEC and TEC groups or between the .03 and .05 tapers with the same instrument tip size (P > 0.05). There was a significantly lower percentage of untouched canal area after instrumentation with size 40 instruments when compared to size 25 (P < 0.05). No significant difference in the percentage of dentine removed was observed between the access cavities or the different tapers (P > 0.05). Size 40 apical preparations removed significantly more dentine than size 25 preparations (P < 0.05). No significant differences were observed in canal transportation, centring ability and fracture resistance in any of the tested groups (P > 0.05). CONCLUSIONS: Ultraconservative endodontic access cavities did not offer any advantages in comparison with traditional endodontic access cavities on the ability to shape canals, nor the fracture resistance of mandibular molars. No differences were observed in shaping ability and fracture resistance between .03 and .05 taper canal preparations. Apical preparation with larger instruments resulted in significantly less untouched canal area in all groups.

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The aim of this clinical study was to evaluate bacterial colonization, marginal bone loss, and optical alveolar density in implants with Morse taper (MT) and external hexagon (EH) connections. Thirty-five implants were installed in 7 patients (mean age: 65.8 ± 6.7 years). Implants were divided into 2 groups, according to platform design: G1 - MT, installed 2mm infra-osseous and G2 - EH, positioned according to Branemark protocol. Patients were evaluated at baseline (T0), 21 days (T1), 3 months (T2), 6 months (T3), and 12 months (T4) after installations. Bone loss and alveolar density were evaluated by standardized periapical radiographs and bacterial profile with checkerboard DNA-DNA hybridization. Statistical analyses were performed using SPSS 23.0. To present the results, boxplots and a line graph of mean were used. P-values ≤ .05 were statistically significant. After 3 months, alveolar bone loss was significantly higher in the G2 (T2-T0: P = .006; T3-T0: P = .003; and T4-T0: P = .005). No significant differences between G1 and G2 groups were observed for optical alveolar density. Microbiological analysis showed similar profiles between studied groups; however, there were significantly higher counts of Tannerella forsythia (P = .048), Campylobacter showae (P = .038), and Actinomyces naeslundii (P = .027) in G1 after 12 months. Based on the results of this study, it can be concluded that there was less peri-implant bone loss in MT compared to EH connections, but microbiological profile did not seem to influence bone changes.

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BACKGROUND: Taper is considered as a strategy to avoid overtraining and increase peak performance in athletes. Because aerobic exercise increases the level and duration of independence during the lifespan, the participation of recreational athletes has increased in running events around the world. However, the effects of using load reduction in their training and aerobic performance are still not well known. OBJECTIVES: Our goal was to compare load manipulations, using tapering-like periods in the end of recreational athletes training evaluating alterations in oxygen supply, muscle injury, and metabolism markers. METHODS: Healthy males (n = 88, 20-35 years old) were randomly distributed in groups using a combination of two mesocycles of 4 weeks, undulatory and staggered, with two daily microcycles, undulatory and linear. Undulatory-undulatory (Und-Und) and undulatory-linear (Und-Lin) groups had load reduction in the final week of training while the staggered-undulatory (Sta-Und) and staggered-linear (Sta-Lin) groups did not. Cardiorespiratory capacity (V̇O2max), body mass index (BMI), and body fat % were evaluated. Blood samples were also collected to analyze hematocrit (Ht), mean corpuscular hemoglobin (MCHC), circulating levels of hemoglobin (Hb), creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea (U), cortisol (C), free testosterone (FT), and free T/C ratio. RESULTS: After 8 weeks of training, Und-Und had the highest trend to increase V̇O2max. Both Und-Und and Sta-Lin reduced body fat %. Und-Und showed a significant increase in MCHC, T and Free T/C ratio, a positive trend to increase Ht% and Hb levels, and a trend to decrease CK, LDH, and C circulating levels. Sta-Lin presented a trend to decrease Ht% and Hb levels, a significant increase in CK, LDH, AST, ALT circulating levels, and a decrease in Free T/C ratio. CONCLUSION: The use of daily undulatory training load provides better gains for aerobic fitness while the use of staggered load, mainly associated with linear load, promotes inadequate recovery in recreational runners.

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BACKGROUND: The goal of this study was to analyze the stress distribution on two types of extra-short dental implants with 5 mm of length: An internal hexagon (IH) and morse taper connection (MT). METHODS: The three-dimensional model was composed of trabecular and cortical bone, a crown, an extra-short dental implant and their components. An axial load of 150 N was applied and another inclined 30° with the same magnitude. RESULTS: Stress concentrations on the IH implant are observed in the region of the first threads for the screw. However, in the MT implant the highest stress occurs at the edges of the upper implant platform. CONCLUSIONS: In view of the results obtained in this study the two types of prosthetic fittings present a good stress distribution. The Morse taper connections presented better behavior than the internal in both loading configurations.

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Este trabalho teve como objetivo avaliar o ajuste de modelos de taper com e sem casca para o clone GG100 em um plantio comercial localizado no sul do estado do Tocantins. Foram cubadas 25 árvores em cujos dados se ajustou cinco modelos de taper, sendo três representando os mais utilizados no Brasil e dois representando os modelos pouco testados no país. Na avaliação dos modelos de taper, adotou-se os critérios estatísticos: erro padrão da estimativa, coeficiente de determinação ajustado, desvio médio, soma de quadrados do resíduo relativo, resíduo percentual e análise da distribuição de resíduos. Concluiu-se por um modelo do tipo expoente-forma para descrever o perfil do tronco com e sem casca de árvores individuais do clone GG100.(AU)

The objective of this work was to evaluate the adjustment of taper models with and without bark for clone GG100 in a commercial plantation located in the southern state of Tocantins. Twenty-five trees were cubed in which data were fitted five taper models, three of which were the most used in Brazil and two representing the poorly tested models in the country. In the evaluation of the taper models, the following statistical criteria were adopted: standard error of the estimate, adjusted coefficient of determination, mean deviation, sum of squares of the relative residue, percentage residue, and analysis of the distribution of residues. It was concluded by an exponent-shape type model to describe the trunk profile with and without bark of individual clones of clone GG100.(AU)

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Este trabalho teve como objetivo avaliar o ajuste de modelos de taper com e sem casca para o clone GG100 em um plantio comercial localizado no sul do estado do Tocantins. Foram cubadas 25 árvores em cujos dados se ajustou cinco modelos de taper, sendo três representando os mais utilizados no Brasil e dois representando os modelos pouco testados no país. Na avaliação dos modelos de taper, adotou-se os critérios estatísticos: erro padrão da estimativa, coeficiente de determinação ajustado, desvio médio, soma de quadrados do resíduo relativo, resíduo percentual e análise da distribuição de resíduos. Concluiu-se por um modelo do tipo expoente-forma para descrever o perfil do tronco com e sem casca de árvores individuais do clone GG100.

The objective of this work was to evaluate the adjustment of taper models with and without bark for clone GG100 in a commercial plantation located in the southern state of Tocantins. Twenty-five trees were cubed in which data were fitted five taper models, three of which were the most used in Brazil and two representing the poorly tested models in the country. In the evaluation of the taper models, the following statistical criteria were adopted: standard error of the estimate, adjusted coefficient of determination, mean deviation, sum of squares of the relative residue, percentage residue, and analysis of the distribution of residues. It was concluded by an exponent-shape type model to describe the trunk profile with and without bark of individual clones of clone GG100.

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A perda total dos dentes ainda é um problema enfrentado por grande parcela da população. Nesse sentido, a Odontologia vem desenvolvendo novos métodos para a reabilitação desses pacientes. As próteses totais mucossuportadas foram amplamente utilizadas sem apresentarem, no entanto, estabilidade e retenção satisfatórias, principalmente na mandíbula. Com os estudos desenvolvidos por Brånemark, que culminaram com o aparecimento dos implantes osseointegráveis, um novo conceito de tratamento de pacientes desdentados totais surgiu: próteses totais implantossuportadas. A partir desse conceito, modificações foram realizadas no protocolo original com o intuito de tornar o tratamento mais rápido, efetivo, barato e menos traumático. Assim, pesquisas foram desenvolvidas para viabilizar o carregamento imediato dos implantes. Outro novo conceito que busca a melhora dos resultados em reabilitações orais é o sistema cone-morse, que apresenta maior resistência mecânica, melhor distribuição e transmissão de forças ao longo do implante para o tecido ósseo, redução do gap, com diminuição da possiblidade de invasão bacteriana na interface do implante intermediário, além da redução do afrouxamento e fraturas de parafusos. Fundamentado nessas considerações, este artigo tem como objetivo apresentar um caso clínico de reabilitação com prótese total imediata implantossuportada por implantes do tipo cone-morse na mandíbula. O resultado mostrou-se bastante satisfatório tanto em relação à estética quanto à função e, principalmente, ao conforto do paciente.

The edentulous condition is still a problem faced by most of the population. In this sense, dentistry has developed new methods for the rehabilitation of these patients. Initially, mucoussupported total prostheses have been widely used however without demonstrating satisfactory stability and retention, particularly in the jaw. With the studies developed by Brånemark culminating in the appearance of modern dental implants, a new concept emerged to treat edentulous patients: total implant-supported fixed prosthesis. From this concept, modifications were made in the original protocol in order to make the treatment faster, effective, inexpensive, and less traumatic. Thus, research has been developed to enable the immediate implant activation. Another new concept that aims to provide better results in the oral rehabilitation is the Morse taper system that has greater mechanical strength, better force distribution and transmission along the implant to the bone tissue, reducing the gap with less chance of bacterial invasion in the prosthetic-implant interface, and still with less loosening and screw fractures. Based on these considerations, this article aims to present a case of an immediate implant-supported mandibular total prosthesis on Morse taper implants. The result was quite satisfactory both in relation to aesthetics, function, but especially for patient's comfort.

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