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1.
Quintessence Int ; 51(2): 142-150, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31781692

RESUMO

OBJECTIVE: High levels of primary implant stability have been advocated particularly for immediate loading protocols. Current implant systems and drill protocols are intended not to cause excessive stress on bone during implant insertion as resorptive processes might compromise esthetics and function. The goal of this narrative review was to summarize current data on the effect of mechanical stress on alveolar bone. METHOD AND MATERIALS: PubMed was searched (final search conducted on 30 September 2019) applying the user query "(dental implant insertion) AND (mechanical stress) AND (bone)." The papers identified were grouped according to the research methodology applied (in vitro studies and finite element analysis, animal studies, and clinical trials). RESULTS: In total, 176 articles were identified, of which 58 were included. A clear tendency towards increased stress in bone resulting from the use of undersized osteotomies was shown. Depending on the degree of undersizing, the inner parts of implant threads create healing chambers in which bone formation seems to progress very well, while areas of direct contact between implant body and alveolar bone experience resorption during healing. More resorption seems to occur when implants have been placed with higher insertion torque, although these implants maintain greater total bone-to-implant contact during initial healing. Clinically, mobile implants seem to have a compromised prognosis and high insertion torques seem not to guarantee successful osseointegration. Marginal bone level changes obviously have a tendency of being greater in implants inserted with high levels of torque. CONCLUSION: Clinicians should be cautious during implant surgery not to overstress bone. Future implant systems should focus on optimized drill protocols and apply macrodesigns that also derive stability from trabecular bone as well, instead of merely compressing the cortical layer.


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Carga Imediata em Implante Dentário , Animais , Implantação Dentária Endo-Óssea , Osseointegração , Estresse Mecânico , Torque
2.
Int Endod J ; 53(2): 250-264, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31489641

RESUMO

AIM: To compare the mechanical properties and metallurgic features of new and used Reciproc Blue and Reciproc instruments. METHODOLOGY: A total of 120 R25 Reciproc Blue and R25 Reciproc instruments were used. The morphological, chemical, mechanical, thermal and phase composition characteristics of new and ex vivo used files were investigated by scanning electron microscopy (FEG-SEM) with energy dispersive X-ray spectroscopy (EDS), focused ion beam analysis (FIB), micro-Raman spectroscopy, FEG-SEM metallography, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and indentation tests. Usage-induce degradation was evaluated. Ten new and ten used instruments per type were run until fracture occurred in a stainless steel artificial canal (60° angle of curvature, 4-mm radius). Time to fracture and the length of the fractured fragment were recorded. Torque and angle of rotation at failure of ten new and ten used instruments for each type were measured according to ISO 3630-1. The fracture surface of each fragment was examined. Two-way analyses of variance was used to analyse the data statistically (α-level 0.05). RESULTS: SEM analysis revealed microcracks near the tip on both files after ex vivo usage tests. FIB imaging and micro-Raman spectroscopy confirmed the presence of an oxide layer on the Reciproc Blue surface. There was no thinning of the coating after use. XRD revealed a reduction of martensite and R-phase in Reciproc Blue after use. DSC analysis revealed different transformation temperatures for the instruments analysed. Reciproc Blue was significantly more flexible than Reciproc for both new and used samples (P < 0.05), and they were significantly more resistant to cyclic fatigue than Reciproc (P < 0.05). Ex vivo usage reduced the fatigue resistance of both files. Torsional resistance of Reciproc and Reciproc Blue was not reduced by simulated use (P > 0.05). CONCLUSIONS: The thermal treatment of Reciproc Blue was associated with a finer structure with smaller grains than Reciproc, which increased its fracture resistance and was also responsible for its reduced hardness and lower elastic modulus. Both files were safe during ex vivo usage in severely curved canals.


Assuntos
Metalurgia , Preparo de Canal Radicular , Desenho de Equipamento , Falha de Equipamento , Dureza , Teste de Materiais , Estresse Mecânico , Propriedades de Superfície , Titânio , Torque
3.
Sports Biomech ; 19(1): 26-54, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29895216

RESUMO

The aim of this study was to conduct a systematic review to determine the quality of evidence of studies assessing isokinetic hip muscle strength in adult non-injured individuals. We also aimed to summarise and pool data of normative values for hip muscle strength. The influence of methodological and participant-related factors on hip strength performance was explored as well. Guidelines proposed in the PRISMA were used to undertake a search strategy involving the keyword 'hip' associated with a set of keywords reflecting muscle strength. Five databases were searched: ProQuest, PubMed, Science Direct, Scopus and Web of Science. From the 2,939 records initially retained, 28 articles were included in this systematic review. Eight articles were classified as high quality. This systematic review exposed the methodological fragility of most studies assessing hip strength in non-injured adult population. Only data from studies with a small number of participants are available to be used as reference. A few individual studies suggest no differences in torque parameters between dominant and non-dominant lower limbs; differences in torque parameters between age groups; and between male and female participants. Overall, reference values for hip muscle performance in isokinetic tests are mostly unclear.


Assuntos
Quadril/fisiologia , Força Muscular/fisiologia , Adulto , Fatores Etários , Fenômenos Biomecânicos , Exercício/fisiologia , Humanos , Dinamômetro de Força Muscular , Valores de Referência , Projetos de Pesquisa/normas , Fatores Sexuais , Torque
4.
Rev. cient. odontol ; 7(2): 75-85, jul.-dic. 2019. ilus
Artigo em Espanhol | LILACS | ID: biblio-1046731

RESUMO

Esta investigación realizó una revisión sobre la colocación de implantes dentales en pacientes con osteoesclerosis idiopática, para lo cual algunos investigadores proponen que se debe tener en cuenta un protocolo específico, el cual habla de un fresado con irrigación externa con suero fisiológico a 5 °C. La estabilidad del implante dental es importante para una buena osteointegración, la cual depende de la calidad ósea, la técnica quirúrgica y la superficie de contacto entre hueso e implante. La fuerza de torque para una buena estabilidad primaria, según una revisión sistemática, es de 20 Ncm a 45 Ncm. Para el éxito de la colocación de implantes dentales, se debe tener un buen diagnóstico de la zona edéntula y una correcta osteointegración. La identificación correcta de los hallazgos clínicos, como la osteoesclerosis idiopática, es importante para diferenciarla de otras patologías óseas benignas y malignas. La osteoesclerosis idiopática se caracteriza por ser asintomática, no tener etiología conocida y no tener tratamiento indicado. El lugar más común donde se presenta esta patología ósea es en el maxilar superior y la zona más prevalente es la zona premolar, aunque algunos autores han reportado la zona molar como la más prevalente para esta condensación ósea. En la actualidad, no existe suficiente investigación sobre la colocación de implantes dentales en pacientes con osteoesclerosis idiopática para determinar la fuerza de torque de inserción con la que se deberían colocar los implantes para una buena estabilidad primaria en una zona con condensación ósea. (AU)


The present review is on the placement of dental implants in patients with idiopathic osteoesclerosis. Some studies have proposed the need for a specific protocol which involves milling with external irrigation with physiological serum at 5 degrees Celsius. The stability of the dental implant is important for good osseointegration, which depends on bone quality, surgical technique and contact surface between the bone and the implant. According to a systematic review, the torque force for good primary stability is 20 to 45 Ncm. Successful placement of dental implants requires accurate diagnosis of the edentulous area and correct osseointegration. It is important to differentiate clinical findings such as idiopathic osteoesclerosis from other benign and malignant bone pathologies. Idiopathic osteosclerosis is characterized as being asymptomatic, having no known etiology, and having no indicated treatment. The most common localization of this bone pathology is in the upper jaw, with the most prevalent area being the premolar area, while some authors have reported the molar area as the most prevalent for this bone condensation. At present, there are few studies on to the force of the insertion torque with which implants should be made to achieve good primary stability in an area with bone condensation in patients with idiopathic osteosclerosis. (AU)


Assuntos
Humanos , Masculino , Feminino , Osteosclerose , Implantes Dentários , Osseointegração , Torque , Diagnóstico Diferencial
5.
Int J Oral Maxillofac Implants ; 34(6): 1397-1403, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31711081

RESUMO

PURPOSE: New solutions need to be developed for cases in which implants that were placed years ago are now presenting prosthetic complications. A conical head screw design for a single-tooth abutment was developed to preserve the initial applied torque. The aim of this study was to assess the preload maintenance of different screw design sets (a conical head screw set and a flat head screw set) for single-tooth abutments in external hexagon implants, verifying whether reverse torque changes after mechanical loading at different crown/implant ratios and to understand if the use of the tested conical head screw set design can help clinicians solve loosening torque. MATERIALS AND METHODS: Forty external hexagonal implants, 40 single-tooth abutments, 20 conical head screws, and 20 flat head screws were split into four groups with different crown/implant ratios (crown/implant ratio > 1 or crown/implant ratio < 1). The abutments were attached to the implants by applying a torque of 35 Ncm; the specimens were mechanically loaded for 1 million cycles, and the loosening torque was checked and recorded with a digital torque wrench. The Kruskal-Wallis test (P = .05) and Wilcoxon test were performed to assess the results. RESULTS: In all groups, at least one specimen kept 100% of the initial applied torque before mechanical loading (t0). After mechanical loading (t1), all specimens presented torque reduction. The Kruskal-Wallis test was performed, and the flat head screw t0 group presented lower torque maintenance and a significant difference (P < .05) compared with the initial applied torque and with the conical head screw t0 group. The conical head screw t0 group presented a higher torque maintenance and no significant difference (P > .05) compared with the initial applied torque. For the flat head screw, the crown/implant ratio affected the torque maintenance. For the conical head screw, the crown/implant ratio did not affect the torque maintenance (P > .05). CONCLUSION: The conical head screw set presented a higher maintenance of applied preload than the flat head screw set. As far as reverse torque is concerned, the crown/implant ratio affects the torque maintenance only in association with a flat head screw set. The use of the tested conical head screw set can help clinicians solve loosening torque, mainly in a situation with a crown/implant ratio > 1.


Assuntos
Implantes Dentários , Prótese Dentária Fixada por Implante , Parafusos Ósseos , Coroas , Dente Suporte , Projeto do Implante Dentário-Pivô , Análise do Estresse Dentário , Torque
6.
Am J Dent ; 32(5): 251-254, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675194

RESUMO

PURPOSE: To evaluate the accuracy of mechanical torque rachet types based on the number of uses. METHODS: A total of 25 ratchets, including three frictional- and two spring-type torque ratchets from every mechanical torque ratchet group, were used in our study. A digital torque measurement device was used in assessing the efficiency of mechanical torque ratchets. All ratchets were tightened according to the torque values recommended by the companies. The ratchets were tightened 500 times in total. RESULTS: Given the changes in torque delivery by the number of uses, a statistically significant torque loss was observed in the Bego ratchets (P< 0.05), and a statistically significant increase was found in the torque values of the other ratchet groups (P< 0.05). The highest increase in torque values was obtained in the MEDENTIKA ratchet group. CLINICAL SIGNIFICANCE: This study showed that there are changes in the torque values applied based on the number of rachet uses. Thus, clinicians are advised to regularly evaluate the accuracy of the rachets.


Assuntos
Instrumentos Odontológicos , Torque
7.
J Oral Sci ; 61(4): 508-511, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31631094

RESUMO

The relation between occlusal force and general motor ability induced by lower-limb musculature is unclear. To identify indicators of oral and lower-limb muscle weakness, this study examined the relation between masticatory muscle strength and lower limb muscle force in 742 community-dwelling elderly adults (315 men and 427 women, mean age 73.3 ± 5.5 years) living in Itabashi ward, Tokyo. Multiple regression analysis of the relation between occlusal force and knee extension torque, in relation to age and sex, showed a significant correlation between the two variables (r = 0.348, P < 0.001), which indicates that occlusal force is a determinant of knee extension torque. Occlusal force remained significantly correlated with knee extension torque after adjustment for factors known to be related to the latter. In conclusion, chewing function and lower-limb motor function were significantly correlated and thus might be indicators of muscle weakness in elderly adults.


Assuntos
Força de Mordida , Vida Independente , Adulto , Idoso , Feminino , Humanos , Joelho , Masculino , Força Muscular , Torque
8.
Braz Oral Res ; 33: e097, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664360

RESUMO

To evaluate the torsional properties of engine-driven pathfinding instruments manufactured from different NiTi alloys - R-Pilot (tip size 12.5;.04 taper; M-Wire) and One G (tip size 14;.03 taper; Conventional NiTi). A total of 40 NiTi instruments from engine-driven pathfinding instruments (n = 20) were used. The torsion tests followed ISO 3630-1 (1992). Three millimeters of each instrument tip was fastened to a small load cell by a lever arm linked to the axis of torsion. During the test, the torsion testing machine software measured the maximum torsional strength and angle of rotation (0) before instrument failure. The fractured surface of each instrument was assessed by scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area and the metal mass volume of each instrument 3 mm from the tip. Data were analyzed using a t-test, with significance level set at 5%. R-pilot had significantly higher torsional strength than did One G (p < 0.05). Regarding the angle of rotation to fracture, One G had higher angles than did R-Pilot (p < 0.05). The supplementary examination showed that R-Pilot had the highest cross-sectional area and volume of metal mass at 3 mm from the tip (p < 0.05). R-pilot (M-Wire NiTi alloy) had a significantly higher torsional strength and One-G (superelastic NiTi alloy) had the highest angle of rotation to fracture.


Assuntos
Ligas/química , Ligas Dentárias/química , Instrumentos Odontológicos , Preparo de Canal Radicular/instrumentação , Análise de Variância , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Microscopia Eletrônica de Varredura , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Estresse Mecânico , Propriedades de Superfície , Torque
9.
J Oral Implantol ; 45(6): 451-455, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31580765

RESUMO

A gap exists at the implant-abutment interface in two-piece implants and can serve as a reservoir of bacteria and compromise the health of peri-implant tissue. This study aimed to compare the effect of different intermediate materials on bacterial leakage at the implant-abutment interface. A total of 75 implants were divided into 5 groups (n = 15) based on the material applied at the implant-abutment connection: (1) Atridox, (2) chlorhexidine, (3) Gapseal silicone, (4) saliva, and (5) no material. All the implants were inoculated with 0.1 µL of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) suspension, and then the respective material was applied. The abutments were connected to the implants, and appropriate torque was applied as recommended by the manufacturer (Implantium, Dentium, Korea, Seoul). Bacterial leakage was determined by evaluating the turbidity of the broth. Bacterial contamination was found in all samples at different times; in groups 1, 2 and 3, contamination was noted after 7, 5, and 6 days, respectively, on average. Contamination occurred averagely after 4 days in groups 4 and 5. The present study showed that Atridox applied at the implant-abutment interface significantly delayed bacterial leakage.


Assuntos
Implantes Dentários , Infiltração Dentária , Dente Suporte , Projeto do Implante Dentário-Pivô , Humanos , Torque
10.
Int J Sports Med ; 40(14): 897-902, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31590190

RESUMO

Sprint cycling performance is heavily dependent on mechanical peak power output (PPO) and the underlying power- and torque-cadence relationships. Other key indices of these relationships include maximum torque (TMAX), cadence (CMAX) and optimal cadence (COPT). Two common methods are used in the laboratory to ascertain PPO: isovelocity and isoinertial. Little research has been carried out to compare the magnitude and reliability of these performance measures with these two common sprint cycling assessments. The aim of this study was to compare the magnitude and reliability of PPO, TMAX, CMAX and COPT measured with isovelocity and isoinertial sprint cycling methods. Two experimental sessions required 20 trained cyclists to perform isoinertial sprints and then isovelocity sprints. For each method, power-cadence and torque-cadence relationships were established, and PPO and COPT were interpolated and TMAX and CMAX were extrapolated. The isoinertial method produced significantly higher PPO (p<0.001) and TMAX (p<0.001) than the isovelocity method. However, the isovelocity method produced significantly higher COPT (p<0.001) and CMAX (p=0.002). Both sprint cycling tests showed high levels of between-session reliability (isoinertial 2.9-4.4%; isovelocity 2.7-4.0%). Functional measures of isovelocity and isoinertial sprint cycling tests were highly reliable but should not be used interchangably.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Teste de Esforço/métodos , Adulto , Humanos , Masculino , Reprodutibilidade dos Testes , Torque , Adulto Jovem
11.
J Chem Phys ; 151(12): 124104, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31575184

RESUMO

An interfacial regularized Stokeslet scheme is presented to predict the motion of solid bodies (e.g., proteins or gel-phase domains) embedded within flowing lipid bilayer membranes. The approach provides a numerical route to calculate velocities and angular velocities in complex flow fields that are not amenable to simple Faxén-like approximations. Additionally, when applied to shearing motions, the calculations yield predictions for the effective surface viscosity of dilute rigid-body-laden membranes. In the case of cylindrical proteins, effective viscosity calculations are compared to two prior analytical predictions from the literature. Effective viscosity predictions for a dilute suspension of rod-shaped objects in the membrane are also presented.


Assuntos
Bicamadas Lipídicas/química , Modelos Químicos , Fenômenos Biomecânicos , Proteínas de Membrana/química , Torque , Viscosidade
12.
Zhongguo Yi Liao Qi Xie Za Zhi ; 43(5): 322-325, 2019 Sep 30.
Artigo em Chinês | MEDLINE | ID: mdl-31625326

RESUMO

Muscle strength training plays an important role in improving limb movement function, preventing muscle atrophy and promoting muscle function recovery in patients with various bone and joint diseases. The sports function of elbow joint is closely related to people's daily life activity ability. At present, Chinese muscle strength training devices are depended on import. Therefore, it is of great significance to develop muscle strength training devices. Based on the concepts and characteristics of isometric training, isotonic training, passive training and isokinetic training, in the upper computer, the servo driver and servo motor are controlled through the LabView interface, and the real-time torque is detected by the torque sensor, realizing four training modes. The main parameters of the multi-mode elbow joint muscle strength training device meet the requirements, and the trainers have a good experience.


Assuntos
Articulação do Cotovelo , Treinamento de Resistência , Articulação do Cotovelo/fisiologia , Humanos , Força Muscular , Músculo Esquelético , Torque
13.
Clin Oral Implants Res ; 30(12): 1238-1249, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31520494

RESUMO

OBJECTIVE: Primary stability is a prerequisite for implant osseointegration. Some degree of misfit between an implant and its osteotomy is required to ensure primary stability, and this is typically achieved by undersizing an implant osteotomy. In this preclinical study, we aimed at understanding the relationship between misfit, insertion torque, implant stability, and their cumulative short- and longer-term effects on peri-implant bone. MATERIALS AND METHODS: We placed implants in maxillary extraction sites of a rat; in the control group, these implants had minimal misfit while those in the test group had a high degree of misfit and therefore osseo-densified the peri-implant bone. RESULTS: Compared to controls, the misfit-induced stresses produced by osseo-densification led to micro-fractures in the peri-implant bone and an extensive zone of dying osteocytes. High interfacial pressures produced a pro-resorptive environment as shown by tartrate-resistant acid phosphatase activity and cathepsin K immunostaining (IHC). The lack of alkaline phosphatase activity and collagen I IHC supported the absence of new bone formation. Collectively, micro-computed tomography imaging, quantification of bone-implant contact (BIC), vimentin, and IL1-ß IHCs demonstrated that implant failure occurred soon afterward, which presented as a crater-like lesion filled with fibrous, inflamed granulation tissue around the test implants. CONCLUSION: By controlling every other risk indicator, we confirmed how excessive osseo-densification can lead directly to osseo-destruction.


Assuntos
Implantes Dentários , Entorses e Distensões , Animais , Osseointegração , Ratos , Torque , Microtomografia por Raio-X
14.
J Prosthodont ; 28(9): 969-972, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31560132

RESUMO

PURPOSE: To compare the reverse torque values (RTVs) of abutment screws tightened from three different angles. MATERIALS AND METHODS: Implant abutment screws (n = 48), abutments (3), and regular platform implant analogs (3) were divided into three angulation groups (n = 16/group). Custom guides of 0°, 10°, and 20° were fabricated to verify driver angulation. The implant components for each group were assembled and all screws torqued to 35 Ncm using a universal screwdriver in a manual torque wrench at the appropriate angle. Torque was reapplied 10 minutes after initial torque. A digital gauge was then used to measure reverse torque at a position parallel (0°) to the implant analog. RTVs were recorded and compared using one-way ANOVA and Tukey HSD post-hoc comparisons (α = 0.05). RESULTS: All mean RTVs fell below the targeted torque value of 35Ncm, with some values in each angulation group 10% below of the target value. Mean RTVs in descending order from targeted torque value were: 10° group = 32.07 ± 0.97 Ncm, 0° group = 31.16 ± 1.12 Ncm, and 20° group = 30.08 ± 0.88 Ncm. One-way ANOVA revealed significant differences between angulation groups (F = 15.954, p < 0.001). Tukey HSD post hoc comparisons revealed that the mean RTVs of the three angulation groups were significantly different from each other (0° vs. 10°: p = 0.033; 0° vs. 20°: p = 0.011; 10° vs. 20°: p < 0.001). CONCLUSIONS: All RTVs did not reach the targeted torque value of 35 Ncm. Mean screw RTVs were significantly influenced by screwdriver insertion angulation.


Assuntos
Implantes Dentários , Dente Suporte , Falha de Restauração Dentária , Análise do Estresse Dentário , Torque
15.
J Oral Implantol ; 45(4): 259-266, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31532728

RESUMO

The primary objective of the present in vitro study was to evaluate the influence of implant site preparation technique (drills vs ultrasonic instrumentation) on the primary stability of short dental implants with two different designs inserted in simulated low-quality cancellous bone. Eighty implant sites were prepared in custom-made solid rigid polyurethane blocks with two different low cancellous bone densities (5 or 15 pounds per cubic foot [PCF]), equally distributed between piezoelectric (Surgysonic Moto, Esacrom, Italy) and conventional drilling techniques. Two short implant systems (Prama and Syra, Sweden & Martina) were tested by inserting 40 fixtures of each system (both 6.0 mm length and 5.0 mm diameter), divided in the four subgroups (drills/5 PCF density; drills/15 PCF density; piezo/5 PCF density; piezo/15 PCF density). Insertion torque (Ncm), implant stability quotient values, removal torque (Ncm), and surgical time were recorded. Data were analyzed by 3-way ANOVA and Scheffé's test (α = 0.05). With slight variations among the considered dependent variables, overall high primary implant stability was observed across all subgroups. Piezoelectric instrumentation allowed for comparable or slightly superior primary stability in comparison with the drilling procedures in both implant systems. The Prama implants group showed the highest mean reverse torque and Syra implants the highest implant stability quotient values. Piezoelectric implant site preparation took prolonged operative time compared to conventional preparation with drills; among the drilling procedures, Syra system required fewer surgical steps and shorter operative time.


Assuntos
Implantação Dentária Endo-Óssea , Implantes Dentários , Densidade Óssea , Poliuretanos , Torque
16.
J Orofac Orthop ; 80(6): 304-314, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31552447

RESUMO

PURPOSE: Torque control in lingual orthodontics is key to obtain optimal esthetic results. The aim of this in vitro experimental study was to verify the efficiency of the ligature-archwire-slot system in torque control using a customized lingual appliance. METHODS: An idealized cast with eight extracted human teeth was created and a set of customized lingual brackets was obtained. Tests were performed with the following wires: 0.016â€³â€¯× 0.022″ nickel-titanium (NiTi), 0.016â€³â€¯× 0.024″ stainless steel (SS), 0.017â€³â€¯× 0.025″ ßIII titanium (ßIIITi), 0.0182â€³â€¯× 0.0182″ ßIIITi, 0.018â€³â€¯× 0.025″ SS, 0.018â€³â€¯× 0.025″ NiTi, 0.018â€³â€¯× 0.025″ ßIIITi, and three types of ligatures were tested using a universal testing machine to calculate the efficiency in torque control. A blind statistical analysis was performed. RESULTS: Based on post hoc multiple comparisons, differences were found for two of the three ligatures when using the 0.016â€³â€¯× 0.022″ NiTi wires (p < 0.001 for both ligatures). When considering all ligatures, 0.018â€³â€¯× 0.025″ SS and 0.018â€³â€¯× 0.025″ ßIIITi were significantly different from all other wires (p < 0.001 in all cases). With a moment of 5 Nmm, the 0.016â€³â€¯× 0.022″ NiTi wire developed median angles of 26.7, 29.8, and 38.7° with the three ligatures, respectively, while the 0.018â€³â€¯× 0.025″ SS developed median angles of 12.9, 10.7, and 12.7°, respectively. CONCLUSIONS: The ligature type and geometry did not affect the efficiency of torque control, except for the 0.016â€³â€¯× 0.022″ NiTi wire. The wires generating the greatest moments were the 0.018â€³â€¯× 0.025″ SS and 0.018â€³â€¯× 0.025″ ßIIITi.


Assuntos
Braquetes Ortodônticos , Fios Ortodônticos , Ligas Dentárias , Análise do Estresse Dentário , Estética Dentária , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Titânio , Torque
17.
Int J Oral Maxillofac Implants ; 34(5): 1084-1090, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31528862

RESUMO

PURPOSE: Stability of an implant-supported restoration is an ultimate measure of the success of the procedure. It has been recommended by some to retighten the abutment screw for maintenance of the crown on the implant. The purpose of this study was to evaluate the usefulness of two retightening protocols to maintain the clamping force. MATERIALS AND METHODS: Three groups of slip-fit implants (MIS 4.3 by 10.5) were compared. The first group was only tightened once (group C). In the second group (group R10M), the screw was retightened after 10 minutes. The third group (group R2W) was retightened after 2 weeks of simulated functional loading. After completion of individual protocols, all specimens were loaded for 100,000 cycles. After the loading, all specimens had the remaining torque audited. RESULTS: The mean torque loss for group C was 6.10 (± 5.13) Ncm. Group R10M was 2.03 (± 3.018) Ncm, and group R2W was 0.30 (± 0.483) Ncm. A one-way analysis of variance (ANOVA) recorded significant differences among the groups (P = .003). Multiple pairwise comparisons between groups by Tukey test recorded significant differences between group C vs group R10M (P = .035) and group C vs group R2W (P = .002). There was no significant difference in torque loss between groups R10M and R2W (P = .509). CONCLUSION: Within the parameters of this in vitro investigation, it was concluded that both retightening after 10 minutes (P = .035) and after 2 weeks (P = .002) was equally effective.


Assuntos
Dente Suporte , Projeto do Implante Dentário-Pivô , Constrição , Análise do Estresse Dentário , Teste de Materiais , Projetos Piloto , Torque
18.
Sports Health ; 11(6): 535-542, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31478791

RESUMO

BACKGROUND: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is unknown. HYPOTHESES: (1) Elbow torque and ball velocity would increase as throwers progressed through a structured long-toss program and (2) intrathrower reliability would be high while interthrower reliability would be variable. STUDY DESIGN: Descriptive laboratory study. LEVEL OF EVIDENCE: Level 3. METHODS: Sixty healthy high school and collegiate pitchers participated in a structured long-toss program while wearing a validated inertial measurement unit, which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Ball velocity was assessed by radar gun. These metrics were compared within and between all pitchers at 90, 120, 150, and 180 ft and maximum effort mound pitching. Intra- and interthrower reliabilities were calculated for each metric at every stage of the program. RESULTS: Ball velocity significantly changed at each progressive throwing distance, but elbow torque did not. Pitching from the mound did not place more torque on the elbow than long-toss throwing from 120 ft and beyond. Intrathrower reliability was excellent (intraclass correlation coefficient >0.75) throughout the progressive long-toss program, especially on the mound. Ninety-one percent of throwers had acceptable interthrower reliability (coefficient of variation <5%) for ball velocity, whereas only 79% of throwers had acceptable interthrower reliability for elbow torque. CONCLUSION: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program. CLINICAL RELEVANCE: Increased ball velocity does not necessarily equate to increased elbow torque in long-toss. Some individuals would likely benefit from individualized long-toss programs for rehabilitation.


Assuntos
Beisebol/fisiologia , Cotovelo/fisiologia , Condicionamento Físico Humano/métodos , Braço/fisiologia , Traumatismos em Atletas/reabilitação , Beisebol/lesões , Fenômenos Biomecânicos , Monitores de Aptidão Física , Humanos , Rotação , Ombro/fisiologia , Equipamentos Esportivos , Torque , Exercício de Aquecimento , Dispositivos Eletrônicos Vestíveis , Adulto Jovem
19.
Int J Sports Med ; 40(12): 779-788, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31487749

RESUMO

Static stretching (SS) can increase joint range of motion (ROM), due to neural, morphological, and physio-psychological factors. Periodized training programs (PD) (e. g., strength, power) are adopted to induce greater adaptations while avoiding overtraining. However, the effectiveness of periodized stretch training adaptations are unknown. Therefore, the objective of this study was to compare the effects of periodized and non-periodized (NP) stretching programs on flexibility, hamstrings stiffness and muscle performance. Sixteen gymnasts were allocated to either periodized or non-periodized SS training and tested pre- and post-8 weeks for countermovement jump height, hip flexors, hip extensors and dorsiflexors ROM, hamstrings stiffness and hamstrings and quadriceps peak torque. Both stretch training groups significantly and similarly increased hip extensor (33.2%), hip flexor (25.2%), and dorsiflexor (23.8%) ROM, hamstrings peak torque (7.9%) and jump height (8.1%) from pre - to post- training. Both groups decreased hamstrings stiffness across the last ten angles (32.1%). PD elicited consistently large magnitude flexibility effect size changes compared to small and moderate magnitude changes for the non-periodized. Therefore, 8-week PD and NP SS programs can decrease young gymnasts' muscle-tendon stiffness and increase muscle performance. However, effect sizes indicate that PD stretch training was more advantageous to increasing flexibility and improving performance.


Assuntos
Desempenho Atlético/fisiologia , Ginástica/fisiologia , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/fisiologia , Criança , Elasticidade , Teste de Esforço/métodos , Feminino , Músculos Isquiotibiais/fisiologia , Articulação do Quadril/fisiologia , Humanos , Músculo Quadríceps/fisiologia , Amplitude de Movimento Articular/fisiologia , Torque
20.
BMC Vet Res ; 15(1): 321, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488151

RESUMO

BACKGROUND: Peak reverse torque (PRT) is a valid method to evaluate implants' secondary stability in the healing bone. The secondary stability is achieved by the implant over time and it has been positively correlated with the implants' osseointegration level. In other words, peak reverse torque is the force required to break the bone-implant interface. The purpose of this study was to compare the peak reverse torque for the self-tapping and non-self-tapping screws used in a dynamic compression plate-screw-bone construct after 60 days of loading when used to stabilize 2.5-cm defects in the tibia of goats. The second objective was to compare the peak removal torque of the screws placed in the different positions to evaluate the impact of construct biomechanics on implants osseointegration. RESULTS: In total, 176 non-self-tapping screws and 66 self-tapping screws were used to fix the 8-holes dynamic compression plates to the bones. The screws were placed in the tibiae from proximal (position sites 1,2, 3) to distal (position sites 4,5,6) and were removed 60 days post-implantation. The animals remained weight-bearing throughout the study period. The screws placed in the proximal diaphysis had significantly less peak reverse torque than screws placed in the distal diaphysis in both groups (p < 0.05). The peak reverse torque resistance was also significantly less for the non-self-tapping screws as compared with the self-tapping screws (p < 0.05). The intracortical fractures in the trans-cortex occurred significantly more frequently during the placement of non-self-tapping screws (p < 0.05) as compared with self-tapping screws (p < 0.05). CONCLUSIONS: Based on these results, we concluded that self-tapping screws may be expected to maintain a more stable bone-implant interface during the first 60 days of loading as compared with non-self-tapping screws. This should be a consideration for orthopedic surgeons and scientists using bone plates to stabilize non-load sharing fractures when a stable plate-screw-bone interface is needed to ensure prolonged stability.


Assuntos
Placas Ósseas/veterinária , Parafusos Ósseos/veterinária , Cabras/cirurgia , Fraturas da Tíbia/veterinária , Animais , Feminino , Tíbia , Fraturas da Tíbia/cirurgia , Torque
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