Consequences of ankle joint immobilisation: insights from a morphometric analysis about fibre typification, intramuscular connective tissue, and muscle spindle in rats.

Orthosis immobilisations are routinely used in orthopaedic procedures. This intervention is applicable in bone fractures, ligament injuries, and tendonitis, among other disorders of the musculoskeletal system. We aimed to evaluate the effects of ankle joint functional immobilisation on muscle fibre morphology, connective tissue, muscle spindle and fibre typification triggered by a novel metallic orthosis. We developed a rodent-proof experimental orthosis able to hold the tibiotalar joint in a functional position for short and long terms. The tibialis anterior muscles of free and immobilised legs were collected and stained by histology and histochemistry techniques to investigate general muscle morphology, connective tissue and muscle fibre typification. Morphometric analysis of muscle cross-section area, fibre type cross-section area, fibre type density, percentage of intramuscular connective tissue, and thickness of the muscle spindle capsule were obtained to gain insights into the experimental protocol. We found that short- and long-term immobilisation decreased the cross-section area of the muscles and induced centralisation of myonuclei. The connective tissue of immobilised muscle increased after 2 and 4 weeks mainly by deposition of type III and type I collagen fibres in the perimysium and endomysium, respectively, in addition to muscle spindle capsule thickening. Type IIB muscle fibre was severely affected in our study; the profile assumed odd shapes, and our data suggest interconversion of these fibre types within long-term immobilisation. In conclusion, our protocol has produced structural and histochemical changes in muscle biology. This method might be applied to various rodent models that enable genetic manipulation for the investigation of muscle degeneration/regeneration processes.

Three-dimensional printing of occlusal devices for temporomandibular disorders by using a free CAD software program: A technical report.

Digital workflow is an important tool in the development of intraoral appliances by additive manufacturing. The purpose of this article is to present a completely digital workflow that uses a free software program and a low-cost 3D printer to fabricate occlusal devices for managing temporomandibular dysfunction. Three-dimensional images were acquired of an open maxillomandibular relationship record by using a scanner. A free software program was used to design the devices, and a 3D printer was used to produce the appliances by using a biocompatible resin. An evaluation of the technique on 5 patients showed good internal fit of the 3D-printed device with a similar need for occlusal adjustment as conventionally fabricated occlusal devices.

Influence of age and gender on sex steroid receptors in rat masticatory muscles.

The temporomandibular muscle dysfunction is characterized by myofascial pain and is more prevalent in women of reproductive age. Sex steroid hormones are hypothetically involved in the dysfunction, but few are the studies of steroid receptors in masticatory and mastication-related muscles. Our aim was to determine estrogen and testosterone receptor expression in rat masticatory and mastication-related muscles within the context of age and gender. Twelve rats were equally divided into four groups: (a) 10-month-old females; (b) 10-month-old males; (c) 24-month-old females; and (d) 24-month-old males. Euthanasia of the females was performed in the proestrous phase (vaginal smears) and the masticatory and accessory muscles were removed for immunohistochemical analysis. Statistical analysis was performed with ANOVA and the Tukey test. Estrogen receptor expression was similarly low in all muscles and groups. Testosterone receptor expression in the Masseter muscle of the 24-month-old male rats was higher than that in the other groups and significantly superior to its expression in the Posterior Digastric muscle. In short, testosterone receptor expression was highest in old male rats. If we generalize to humans, this fact could indicate age- and sex-related hormonal influence on temporomandibular muscle dysfunction. Further studies, however, are necessary to strengthen this hypothesis.

CEREC Chairside System to Register and Design the Occlusion in Restorative Dentistry: A Systematic Literature Review.

OBJECTIVE: The aim of this review was to update the literature with regard to the digital methods available by CEREC Chairside system to register and design the occlusion, to report their efficacy and technical innovations in the field of Restorative Dentistry. A search strategy was performed using the key-words: "virtual articulator," or "CAD-CAM and occlusal recording," or "CAD-CAM and occlusion register," or "CAD-CAM and occlusal contacts," or "CAD-CAM and prosthesis." MATERIAL AND METHODS: Inclusion criteria comprised studies evaluating the use of digital methods available by CEREC System for occlusal registration and design during prosthodontics treatment. PubMed and Cochrane library and reference lists were searched up to January 2016. RESULTS: The search resulted in 280 articles after removing duplicates. Subsequently, 233 records were excluded and 49 studies were selected for reading in full. Eleven articles were considered eligible for the systematic review (4 in vitro and 7 clinical studies). CONCLUSION: Scientific evidence suggests that digital methods were accurate to register and design the occlusion of dental prostheses. Nevertheless, further clinical studies are required to establish a conclusion with regard to its accuracy in prosthodontics treatment. CLINICAL SIGNIFICANCE: Digital technologies allow the design of occlusal surfaces of CAD-CAM fabricated prostheses using innovative approaches. This systematic review aimed to update the literature to help dentists determine the most appropriate digital method to register and design the occlusal surface of CAD-CAM crowns. (J Esthet Restor Dent 28:208-220, 2016).

Use of Silver Nanoparticles Reduces Internal Contamination of External Hexagon Implants by Candida albicans.

Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface by Candida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.

Use of Silver Nanoparticles Reduces Internal Contamination of External Hexagon Implants by Candida albicans

Abstract: Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface byCandida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.

Resumo: A interface implante/pilar não pode ser totalmente selada para passagem de microrganismos, com isso o interior do implante torna-se um reservatório de microrganismos patogênicos que promovem e mantêm a inflamação crônica nos tecidos em volta dos implantes. Nanopartículas de prata são agentes antimicrobianos potentes e de amplo espectro. O objetivo deste estudo foi avaliar a capacidade das nanopartículas de prata em evitar a contaminação porCandida albicans do interior de implantes, originada da infiltração do fungo através da interface implante/pilar. 36 implantes foram utilizados neste experimento. Três grupos de estudo foram estabelecidos: grupo experimental (os implantes receberam aplicação de nanopartículas de prata na sua cavidade interna, antes da instalação do pilar); grupo controle positivo (os implantes receberam PBS estéril em vez das nanopartículas de prata) e grupo controle negativo (implantes receberam aplicação de nanopartículas de prata na cavidade interna, mas os implantes foram imersos em meio estéril). Nos grupos controle positivo e experimental, os implantes foram imersos em suspensão deCandida albicans. Os pilares protéticos de todos os grupos foram parafusados com torque de 10 N. Após 72 h imersos na suspensão deC. albicans ou em meio estéril, os pilares foram removidos e amostras da superfície interna dos implantes foram coletadas com cone de papel absorvente para a detecção de Candida. No grupo controle negativo não foi observada contaminação por C. albicans. O grupo-controle positivo mostrou valores de unidades formadoras de colônia deCandida estatisticamente maiores quando comparado com o grupo experimental. Conclui-se que nanopartículas de prata reduzem a colonização de C. albicans dentro dos implantes, mesmo quando o pilar é parafusado com torque baixo.

Polarização dos macrófagos em reparação e regeneração tissular / Macrophage polarization in repair and regeneration tissue

A interação entre macrófagos e a superfície do implante considera a adsorção de proteínas como primeiro acontecimento no qual determina os processos celulares consequentes e pode ser fulcral para o desenvolvimento de novas estratégias de biocompatibilidade e engenharia de tecidos. Os macrófagos além de participarem do infiltrado inflamatório em reposta durante a implantação no estado inicial da fase inflamatória, onde predominam atividades fagocitárias, também atuam na fase tardia predominante de atividades anti- inflamatórias e reparação tecidual. Eles podem ser identificados na polarização de dois fenótipos diferentes, denominados æÆclássicoÆÆ ativado (M1) ou æÆalternativoÆÆ ativado (M2). São dois subgrupos funcionais os quais apresentam quadros comportamentais inflamatórios e anti-inflamatórios. M2 pode ser ordenado em três subtipos distintos, denominados M2a, M2b e M2c, baseados, sobretudo, nos agentes de indução e expressão do marcador molecular. M2d é resultante de mediadores dependentes da adenosina do macrófago M1, que exibe um padrão de expressão do marcador distinto do IL-4 / IL-13 dependente dos macrófagos M2...

Interaction between macrophages and the implant surface considers protein adsorption as the first event in which the resulting cellular processes are determined and can be crucial for development of new strategies for biocompatibility and tissue engineering. Besides taking participating of the inflammatory infiltrate in response during deployment in the initial stage of the inflammatory phase, in which predominate phagocytic activities, macrophages also act on the predominant late stage of anti-inflammatory activity and tissue repair. They can be identified in two different polarization phenotypes, called ôclassicõ activated (M1) or ôalternativeõ activated (M2), sub-groups with inflammatory and anti-inflammatory functional behavior. M2 can be ordered in three different subtypes, named M2a, M2b, and M2c grounded mainly on inducing agents and expression of molecular marker. M2d results from macrophage mediators of adenosine M1, which exhibits a distinct pattern of expression of marker IL-4 / IL-13 dependent on the M2 macrophages...

Silver nanoparticles in dental biomaterials.

Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time.

Characteristics related to TMJ arthralgia, visualized by magnetic resonance imaging (3.0 Tesla).

PATIENTS: Six women, with ages ranging from 52 to 64 years old, clinically evaluated (Research Diagnostic Criteria for Temporomandibular Disorders) by a single examiner were submitted to MRI (3.0 T). They had only arthralgia diagnosis. The images were evaluated by two radiologists who were not informed about the patients' clinical conditions, in which discs displacements, osteophytes and morphological irregularities, as well as completely normal images, i.e., without any characteristics were identified. DISCUSSION: TMJ arthralgia can be caused by various conditions, few of which are objectively observed when investigating its causes or diagnose temporomandibular disorders (TMD). In some cases, imaging exams can detect some conditions and magnetic resonance imaging (MRI) is commonly used for this purpose. Here, the MRI (3.0 T) enabled a detailed visualization of the structures of the TMJ, allowing the characterization of the symptomology in some cases. Despite, some images were completely normal. CONCLUSION: This case report detected some features seen on the MRI that justified a clinical diagnosis arthralgia, not associated with other clinical diagnosis. However, the detailed clinical examination should be sovereign even in the face of equipment with advanced technology.

Prevalence of signs and symptoms of temporomandibular dysfunction in female adolescent athletes and non-athletes.

OBJECTIVES: To compare the prevalence of signs and symptoms of temporomandibular dysfunction (TMD) in female adolescent athletes and non-athletes and to examine the association between signs and symptoms of TMD in female adolescents in different Tanner stages. METHODS: The subjects were 89 female basketball and handball players ages 10-18 years and 72 female non-athlete adolescents ages 10-19 years selected from the Department of Pediatrics (School of Medicine, Federal University of São Paulo) as a control group. A survey was used to assess the signs and symptoms of TMD. According to the answers on the survey the adolescents were classified in two categories: no signs or symptoms present (score A-absent), at least one sign or symptom present (score P-present). The ones who got score "P" were submitted to a standardized functional examination of the masticatory system by four previously calibrated examiners. Pubertal status was assessed based on physical examination by physicians from our Division. The adolescents were classified according to Tanner stages into three subgroups: subgroup 1 (before the growth spurt), subgroup 2 (growth spurt period), subgroup 3 (end of growth spurt). Significant differences between athletes and non-athletes were assessed for categorical variables (Chi-square and Fisher's exact test) and for continuous variables (Mann-Whitney test). The level of significance used was 5%. There was significant agreement between raters, kappa-values (0.621-1.000) and ICC values (0.757-0.899). RESULTS: There was no significant difference between the athletes and non-athletes in exhibiting at least one sign or symptom of TMD (p=0.301). When comparing the adolescents who presented at least one symptom of TMD to the different subgroups of Tanner stages no statistically significant differences were found (p=0.124). CONCLUSION: The lack of significant differences among female adolescent athletes and non-athletes and among the subgroups of Tanner stages may suggests that although contact sports increase the risk of temporomandibular joint lesions and estrogen levels are risk factor for onset of TMD, they do not impact significantly on the onset of this disorder, when considered alone.

Translation and cross-cultural adaptation of the manchester orofacial pain disability scale.

OBJECTIVES: The purpose of the present study was to translate and perform a cross-cultural adaptation of Manchester Orofacial Pain Disability Scale to the Portuguese language. MATERIAL AND METHODS: A synthesis of two independent translations done by bilingual translators whose mother tongue was the Portuguese language began the process of translation. From the synthesis of the translated version and totally blind to the original version, two different non-native English language teachers without dental knowledge translated the questionnaire back to English. The pre-final version was done by an Expert committee: the researchers, two other non-native English language teachers and one native English language speaker. The new questionnaire was then piloted among 8 patients from the target setting that were interviewed to probe it on their perceived meaning of each question. The Manchester Orofacial Pain Disability Scale (MOPDS) thus translated was called Brasil-MOPDS and was validated in 50 patients with Orofacial pain from TMJ and Occlusion clinic ambulatory of São Paulo University School of Dentistry. The Brasil-MOPDS was administered twice by an interviewer (15 - 20 day interval) and once by a second independent interviewer. The Brazilian version of the short form oral health impact profile (OHIP-14) questionnaire and the visual analogue pain scale (VAS) were applied on the same day. RESULTS: Internal consistency (Cronbach's α = 0.9), inter-observer (ICC = 0.92) and intra-observer (ICC = 0.98) correlations presented high scores. Validity of Brasil-MOPDS compared to OHIP-14 (r = 0.85) and VAS (r = 0.75) shown high correlations. CONCLUSIONS: Brasil-MOPDS was successfully translated and adapted to be applied to Brazilian patients, with satisfactory internal and external reliability.

Connecting accuracy of interchanged prosthetic abutments to different dental implants using scanning electron microscopy

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.

O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de implante/pilar possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um dado pilar colocado sobre um implante fosse igual ou menor que a diferença medida quando o pilar da mesma marca do implante fora posicionado. Os dados foram comparados pelo teste de Kruskal-Wallis com nível de significância de 5%. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar anti-rotacional foi mais preciso do que o rotacional. Estes variaram de 0,6-16,9 µm, com mediana 4,6 µm; enquanto o anti-rotacional foi de 0,3-12,9 µm, com mediana de 3,4 µm. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e Neodent (p<0,05). Apesar destes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis.

Connecting accuracy of interchanged prosthetic abutments to different dental implants using scanning electron microscopy.

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.

Deformação do colar de implantes com junta friccional – estudo qualitativo preliminar pela Espi / Deformation of the implant collar on frictional joint implants - an Espi preliminary qualitative study

A região do colar cervical do implante é constantemente exposta aos esforços mastigatórios/parafuncionais, representando uma zona em potencial à ocorrência de deformações, principalmente nos implantes de conexão interna e de reduzido diâmetro. Estas sobrecargas representam um dos fatores responsáveis pela perda óssea ao redor dos implantes. O presente estudo avaliou o comportamento do colar de implantes friccionais (Kopp) de dois diâmetros (4,3 mm e 5,5 mm) sob cargas compressivas estáticas (cêntrica e excêntrica) de duas intensidades (50 N e 100 N) por meio da Interferometria Eletrônica de Padrões de Speckle (Espi – Electronic Speckle Pattern Interferometry). A técnica Espi consiste na comparação de imagens, de antes e após o carregamento, obtidas a partir da reflexão de uma fonte de luz laser incidida sobre um objeto real de superfície rugosa, resultando em um padrão de franjas. O estudo in vitro visou testar a aplicabilidade da técnica Espi para avaliar implantes e a hipótese de que quanto maior o diâmetro do implante, maior é sua resistência ao deslocamento. Foi possível obter resultados qualitativos reprodutíveis acerca da deformação ao nível do colar do implante frente aos carregamentos, validando a técnica. Franjas horizontais foram observadas nas cargas cêntricas, demonstrando o deslocamento vertical do colar do implante e franjas diagonais nas cargas excêntricas, demonstrando o deslocamento de forma oblíqua. Estes deslocamentos podem sugerir a deformação sofrida pela amostra. A técnica Espi mostrou-se viável para avaliar as deformações da região observada e a hipótese foi confirmada, visto que no implante de menor diâmetro houve maior deformação.

The collar region of osseointegrated implants is frequently exposed to masticatory/parafunctional loads, representing a potential area subjected to deformation, especially in narrow-diameter and internal connection dental implants. This study evaluated the effect of the collar of frictional implants (Kopp) at two different diameters (4.3 mm and 5.5 mm) under static compressive loads (centric and eccentric) of two magnitudes (50 and 100 N) through the Electronic Speckle Patterns Interferometry (Espi). The Espi is a technique still little used in dentistry that consists in comparing images before and after loading, obtained from the reflection of a laser light source focused on a real object surface resulting in a fringe pattern. The in vitro study aimed to test the applicability of the ESPI technique and the hypothesis that as larger is the implant diameter, as greater is the resistance to strain at level of implant collar. It was possible to obtain reproducible qualitative results about the deformation of the implant collar when subjected to loading, validating this technique. Fringes were observed horizontally in the centric loads and diagonally in eccentric loads. These results may suggest the deformation suffered by the sample. The Espi technique was feasible to assess the deformation of the region observed and the hypothesis was confirmed, since the smaller implant diameter presented greater strain.

Valores de destorque após torque inicial em implantes CM com diferentes diâmetros – estudo in vitro / Detorque values after initial torque in Morse Taper implants of different diameters – an in vitro study

A perda da pré-carga e o consequente afrouxamento dos parafusos de fixação das próteses sobreimplantes é uma preocupação permanente nas reabilitações protéticas, principalmente nas próteses unitárias. O objetivo deste estudo foi avaliar a influência das dimensões da conexão cônica entre o implante e o pilar protético no torque e no destorque em implantes do tipo cone-morse. Foram utilizados 20 corpos de prova divididos em dois grupos experimentais: grupo 1 – dez corpos de prova compostos de implantes do tipo Titamax Cone Morse (Neodent, de 3,75 mm de diâmetro) e dez pilares CM (Neodent); grupo 2 – dez implantes do tipo Titamax WS (Neodent, de 5,0 mm de diâmetro) sobre os quais foram aplicados dez pilares WS (Neodent). Esses pilares que são indicados para próteses unitárias parafusadas foram submetidos a torque inicial de 32 Ncm, conforme indica o fabricante, seguidos de nove tratamentos de destorque e retorques sempre em 32 Ncm. Os valores de destorque para cada pilar, dados em Ncm, foram catalogados e submetidos a testes estatísticos. Os resultados demonstraram que, para os implantes CM, houve redução na média do valor do torque, estatisticamente significante, desde a primeira aferição de destorque (30,0 ± 2,1 Ncm, p = 0,017) até a última aferição (28,87 ± 0,35 Ncm, p = 0,000). Para os implantes WS, houve um aumento estatisticamente significante na média do valor do destorque na primeira aferição (36,25 ± 1,99 Ncm, p = 0,027) e uma redução estatisticamente significante a partir da terceira aferição de destorque (31,12 ± 0,35 Ncm, p = 0,000). Foi possível concluir que o destorque inicial nos implantes WS foi maior que o torque inicial e nos implantes CM foi menor. Após o afrouxamento do pilar e retorqueamento com o mesmo torque inicial, o destorque foi menor para ambos os grupos WS e CM e que, após alguns afrouxamentos e reapertos (quatro a cinco vezes), o torque de afrouxamento manteve-se constante para os dois grupos, por volta de 28 Ncm

The loss of preload and consequent screw loosening of implant-supported prostheses is a fundamental concern in prosthetic rehabilitation, especially in single-tooth situations. The aim of this study was to evaluate the influence of implant-abutment connection dimensions on torque and detorque values of Cone Morse implants. Twenty specimens were divided into two groups: G1: 10 consisting of CM abutments connected to Titamax Morse Taper type implants (Neodent, 3.75 mm-diameter) and G2: 10 consisting of WS abutments connected to WS Titamax Morse Taper type implants (Neodent, 5.0 mm-diameter). First, the abutments were subjected to a 32 Ncm torque followed by nine measurement sets of torque/detorque values. Those values were categorized and subjected to statistical analysis. The results demonstrated that for the CM implants, there was a reduction in the average torque values, being statistically significant since the first (30,00 ± 2,13 Ncm, p = 0,017) until the last detorque measurement (28,87 ± 0,35 Ncm, p = 0,000). For WS implants, there was a statistically significant increase in the average value for the first detorque measurement (36,25 ± 1,99 Ncm, p = 0,027) and a statistically significant reduction from the third detorque measurement (31,12 ± 0,35 Ncm, p = 0,000). It was concluded that: initial detorque values for WS implants were greater than initial torque; in the CM implant, the initial detorque value was smaller than the initial torque. After abutment tightening/loosening with the same initial torque value, detorque values were lower in both groups and afterwards detorque was constant in both groups

Análise comparativa das discrepâncias de assentamento de copings metálicos obtidos pela fundição da liga de NiCr e sinterização do pó de titânio / Comparative analysis of the discrepancies between the seating of metal copings obtained by NiCr alloy casting and titanium powder sintering

O objetivo deste trabalho foi avaliar as discrepâncias de assentamento de copings metálicos fundidos e sinterizados. Para tanto, foram comparados dois grupos de oito copings metálicos; um deles obtido pela técnica de fundição (NiCr) e outro pela técnica da sinterização (Ti-6Al-7Nb). Em ambos foi avaliada a adaptação dos mesmos sobre um troquel metálico com as características e medidas proporcionais a um preparo para coroa total em molar. A leitura da adaptação foi feita em oito pontos equidistantes do perímetro de cada coping por meio de um cabeçote micrométrico digital acoplado a um microscópio óptico de medição (Mitutoyo Mfg. Co., Tó-quio, Japão). Os dados obtidos foram submetidos ao teste t de Student, no qual verificou-se que a comparação entre as médias não apresentou diferenças estatisticamente significantes (t = 0,44; gL = 14; p = 0,668) ao nível de 5%. Os valores médios foram próximos e de mesma variabilidade (coeficiente de variação = 34,41 e 34,50%). Pôde-se concluir que os procedimentos de fundição ou sinterização não influenciaram na justeza de adaptação marginal dos copings metálicos e os copings de titânio, obtidos pela sinterização, podem ser uma alternativa satisfatória para a restauração de elementos protéticos.

Inovações tecnológicas em reabilitação oral protética / Technological innovations in prosthetic oral rehabilitation

Na reabilitação oral protética, as técnicas e materiais são adaptações que vieram da engenharia, física e química e se adequaram muito bem na Odontologia, tornando os trabalhos protéticos cada vez mais estéticos, funcionais e resistentes. Essa interação entre as áreas é essencial para o aperfeiçoamento técnico e científico, em busca de alternativas mais precisas e eficientes. As áreas mais promissoras, atualmente, abordadas neste trabalho, são as porcelanas, a prototipagem, o laser e a bioengenharia. As pesquisas e interações com outras áreas estão muito avançadas e sugerem que os estudos continuarão até o desenvolvimento da terceira dentição permanente, contando com o desenvolvimento da bioengenharia. O objetivo deste trabalho é fazer uma revisão a respeito das novas tecnologias aplicadas em prótese dentária a fim de que o cirurgião-dentista tenha acesso às novidades e, baseado em pesquisas, possa oferecer ou indicar o melhor, mais moderno e o tratamento mais adequado ao seu paciente.

In oral prosthetic rehabilitation, the majority of techniques and materials are adaptations from engineering, physics and chemistry. They have adjusted very well in Dentistry, making the prosthetic work more aesthetic, functional and strong. This interaction between the areas is essential for the technical and scientific improvement and for the search for more accurate and effective alternatives. Currently, the most promising areas, which will be reviewed in this work, are the porcelains, prototyping, laser and bioengineering. Research and interactions with other areas are very advanced and suggest that the studies will continue until the development of the third permanent dentition, counting on the development of bioengineering. The aim of this work is to undertake a literature review on the new technologies applied in prosthodontics so that the dentist is given access to new features and, based in research, can offer or the best, more modern and more appropriate treatment to the patient.

2D and 3D finite element analysis of central incisor generated by computerized tomography.

The purpose of this study was to compare the results of different hierarchical models in engineering analysis applied to dentistry with 2D and 3D models of a tooth and its supporting structures under 100 N occlusal loading at 45° and examine the reliability of simplified 2D models in dental research. Five models were built from computed-tomography scans: four 2D models with Plane Strain and Plane Stress State with linear triangular and quadratic quadrilateral elements and one 3D model. The finite element results indicated that the stress distribution was similar qualitatively in all models but the stress magnitude was quite different. It was concluded that 2D models are acceptable when investigating the biomechanical behavior of upper central incisor qualitatively. However, quantitative stress analysis is less reliable in 2D-finite element analysis, because 2D models overestimate the results and do not represent the complex anatomical configuration of dental structures. Therefore 3D finite element analyses of dental biomechanics cannot be simplified.

Análise biomecânica em prótese parcial fixa: método dos elementos finitos / Biomechanics analysis in fixed partial prosthesis: finite elements method

O objetivo deste estudo foi analisar a distribuição de tensões de von Mises em uma prótese parcial fixa de três elementos em metalocerâmica e em dois sistemas de cerâmica pura através de carregamento estático aplicado em modelos matemáticos bidimensionais obtidos pelo método de elementos finitos. A partir da imagem de uma peça anatômica de estudo, os desenhos foram confeccionados e suas imagens vetorizadas foram “exportadas” para o programa MSC/PATRAN e a análise foi feita utilizando-se um carregamento de 100N distribuídos em 17 pontos das superfícies oclusais dos modelos. Em todos os modelos as maiores concentrações de tensões localizaram-se no interior dos pinos e na região médio-inferior dos conectores. Os dois sistemas cerâmicos se comportaram satisfatoriamente em comparação à metalocerâmica.