Are exercises with or without occlusal splints more effective in the reduction of pain in patients with temporomandibular disorders of myogenic origin? A systematic review

Abstract Temporomandibular disorders (TMD) is a term used to describe a set of clinical conditions that may compromise the temporomandibular joint (TMJ) and masticatory muscles and/or associated structures, considered the most frequent cause of orofacial pain of non-dental origin. In recent years, many forms of physical therapy have been used in the treatment of TMD to reduce pain and improve the range of mandibular movement present in this impairment. Among these resources are kinesiotherapy (exercise), electrothermal and manual therapy, acupuncture, training posture, mobilizations, and biofeedback. Objectives To determine if exercises with or without occlusal splints are effective in reducing pain in patients with temporomandibular disorders (TMD) of myogenic origin. Methodology This systematic review was registered in the International Prospective Register of Systematic Reviews (CRD 42019134244). Controlled trials published in PubMed, Scopus, and Cochrane Library following PRISMA guidelines up to April 2022 were randomized and included. The population above 18 years, which evaluated the effectiveness of exercise with or without occlusal splints in reducing pain in patients with TMD of myogenic origin, diagnosed through the Research Diagnostic Criteria for Temporomandibular Disorders, was also included. There was no restriction on the period of publication. Cochrane risk of bias analysis was performed. Results Of the five included articles, all showed a reduction of pain, but without significant differences between the interventions performed. Additionally, studies that evaluated the quality of life and mandibular movements showed a reduction in pain, but no significant differences between therapies. Conclusion The analyzed studies showed no difference in the improvement of pain, quality of life, and mandibular movements between the groups that performed only exercises or the associated treatments.

Polymorphisms of the serotonin receptors genes in patients with bruxism: a systematic review

Abstract This study aimed to investigate if SNP rs6313, SNP rs2770304, SNP rs4941573, and SNP rs1923884 of the 5-HT2A receptor gene and SNP rs6295 of the 5-HT1A receptor gene are associated with bruxism etiology. Methodology This systematic review was registered in PROSPERO (CRD42018094561). A search was conducted for articles published in or before May 2021. To qualify for eligibility in this review, the studies had to be case-controls, cohort or cross-sectional. The inclusion criteria were the articles with a group of patients with bruxism and a control group in which the presence of these SNPs was evaluated. The exclusion criteria were the investigations of other polymorphisms, the studies that did not consider a control group for comparison, case reports, and reviews. The NOS and JBI were used to evaluate the methodological quality of studies. Results We conducted this study with databases, such as Web of Science, Scopus, Embase, PubMed/MEDLINE, and ProQuest. We considered four studies eligible. A total of 672 participants were included,187 with sleep bruxism, 105 with awake bruxism, 89 with sleep and awake bruxism, and 291 controls. One study found a strong association between the SNPs rs6313, rs2770304 and rs4941573 of the 5-HT2A receptor gene and sleep bruxism. In one study, we considered the C allele of the SNP rs2770304 a risk factor for sleep bruxism. We found no significant results of other SNPs in sleep bruxers compared to controls. We found no positive association concerning the SNPs and groups of awake bruxism and sleep and awake bruxism. Conclusion The different results regarding the SNPs in sleep bruxers could be explained by the genetic distinction between Chilean, Mexican, Japanese, and Polish population. More clinical trials and prospective studies must be conducted with larger sample size and in different ethnicities to confirm the results of this review.

Three-Dimensional Finite Element Analysis of Varying Diameter and Connection Type in Implants with High Crown-Implant Ratio

Abstract The aim of this study was to evaluate the effect of varying the diameter, connection type and loading on stress distribution in the cortical bone for implants with a high crown-implant ratio. Six 3D models were simulated with the InVesalius, Rhinoceros 3D 4.0 and SolidWorks 2011 software programs. Models were composed of bone from the posterior mandibular region; they included an implant of 8.5 mm length, diameter Ø 3.75 mm or Ø 5.00 mm and connection types such as external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Models were processed using the Femap 11.2 and NeiNastran 11.0 programs and by using an axial force of 200 N and oblique force of 100 N. Results were recorded in terms of the maximum principal stress. Oblique loading showed high stress in the cortical bone compared to that shown by axial loading. The results showed that implants with a wide diameter showed more favorable stress distribution in the cortical bone region than regular diameter, regardless of the connection type. Morse taper implants showed better stress distribution compared to other connection types, especially in the oblique loading. Thus, oblique loading showed higher stress concentration in cortical bone tissue when compared with axial loading. Wide diameter implant was favorable for improved stress distribution in the cortical bone region, while Morse taper implants showed lower stress concentration than other connections.

Resumo O objetivo deste estudo foi avaliar o efeito da variação do diâmetro e dos tipos de conexão na distribuição do estresse no osso cortical para implantes com a proporção coroa-implante. Seis modelos 3D foram simulados com os programas InVesalius, Rhinoceros 3D 4.0 e SolidWorks 2011. Os modelos foram compostos de osso da região mandibular posterior. Foram incluídos implantes de 8,5 mm de comprimento, diâmetro Ø 3,75 mm ou Ø 5,00 mm, e tipos de conexão como hexágono externo (EH), hexágono interno (IH) e cone Morse (MT). Os modelos foram processados usando os programas Femap 11.2 e NeiNastran 11.0 e usando uma força axial de 200 N e força oblíqua de 100 N. Os resultados foram registrados em termos da tensão principal máxima. O carregamento oblíquo mostrou alta tensão no osso cortical em comparação com a carga axial. Os resultados mostraram que os implantes com maior diâmetro apresentaram distribuição de tensões mais favorável, independentemente do tipo de conexão, enquanto que os implantes cone Morse apresentaram melhores distribuição de tensões comparado aos outros tipos de conexão, especialmente no carregamento oblíquo. Assim, os implantes de maior diâmetro foram mais favoráveis para distribuição das tensões na região de tecido ósseo cortical, enquanto que os implantes cone Morse apresentam menores concentrações de tensões do que as outras conexões.

Short implants versus longer implants with maxillary sinus lift. A systematic review and meta-analysis

Abstract This study compared the survival rate of dental implants, amount of marginal bone loss, and rates of complications (biological and prosthetic) between short implants and long implants placed after maxillary sinus augmentation. This systematic review has been registered at PROSPERO under the number (CRD42017073929). Two reviewers searched the PubMed/MEDLINE, Embase, LILACS, and Cochrane Library databases. Eligibility criteria included randomized controlled trials, comparisons between short implants and long implants placed after maxillary sinus augmentation in the same study, and follow-up for >6 months. The Cochrane Collaboration's tool for assessing the risk of bias in randomized trials was used to assess the quality and risk of bias of the included studies. The search identified 1366 references. After applying the inclusion criteria, 11 trials including 420 patients who received 911 dental implants were considered eligible. No significant difference was observed in the survival rate [p = 0.86; risk ratio (RR): 1.08; 95% confidence interval (CI): 0.46-2.52] or in the amount of marginal bone loss (p = 0.08; RR: −0.05; 95%CI: −0.10 to 0.01). However, higher rates of biological complications for long implants associated with maxillary sinus augmentation were observed (p < 0.00001; RR: 0.21; 95%CI: 0.10-0.41), whereas a higher prosthetic complication rate for short implants was noted (p = 0.010; RR: 3.15; 95%CI: 1.32-7.51). Short implant placement is an effective alternative because of fewer biological complications and similar survival and marginal bone loss than long implant placement with maxillary sinus augmentation. However, the risk of mechanical complications associated with the prostheses fitted on short implants should be considered.

Complications with PMMA compared with other materials used in cranioplasty: a systematic review and meta-analysis

Abstract Polymethyl methacrylate (PMMA) has been considered a suitable material for cranioplasty. However, no consensus has been reached concerning the best material for cranioplasty with regard to minimizing complications. Thus, this systematic review and meta-analysis aimed to compare the complication rates of PMMA with those of autologous bone and titanium mesh. This review was registered with PROSPERO (CRD42016042725). Systematic searches were conducted on PubMed/MEDLINE, Scopus, and Web of Science. The focus question was, "Do PMMA prostheses used in cranioplasty have complications rates similar to those of autologous bone and titanium mesh?" A meta-analysis of complication rates was performed on the basis of dichotomous outcomes assessed by risk ratio (RR) with corresponding 95% confidence intervals (CI). From 1014 data sources, 11 articles were selected according to eligibility criteria. These articles involved 1,256 individuals and 1,278 cranioplasties using autologous bone (n = 408), PMMA (n = 379), or titanium (n = 151). The follow-up period ranged from 63 days to 54.3 months. No difference was observed between the complication rates of PMMA and autologous bone (p = 0.94; RR, 0.98; 95%CI, 0.54-1.75) or between PMMA and titanium (p = 0.38; RR, 1.59; 95%CI, 0.57-4.48). Sub-analysis of the reasons for craniotomy (trauma/non-trauma) was conducted, which revealed no significant difference (p = 0.91; RR, 0.95; 95%CI, 0.37-2.42). The meta-analysis indicated that the use of PMMA yields complication rates that are near those of autologous bone and titanium mesh.

Influence of diameter and intraradicular post in the stress distribution. Finite element analysis / Influência do diâmetro e do retentor intrarradicular na distribuição de tensões. Análise pelo método dos elementos finitos

Introduction: The biomechanical behavior of endodontically treated teeth depending on the selected restorative material and tooth situation to be restored. Objective: To analyze by the two-dimensional finite element method the biomechanical behavior of different diameters in intraradicular posts and teeth with coronal remaining of 2mm. Material and method: Six models were made with three types of posts, as follows: Glass fiber post, carbon fiber post, and cast metal post, both with diameter # 1 (1.1 mm in diameter) and # 2 (1.3 mm of diameter). The modeling was performed using the Rhinoceros 4.0 program. The FEMAP 10.2 and NEiNastran 9.2 programs were used to develop finite element models. The loading used was 100N for axial and oblique forces. The results were visualized using the von Mises stress map. The statistical analysis was made using analysis of variance (ANOVA) and Tukey post-test, with a significance level of 5%. Result: The oblique loading stress values were higher than the axial loading (p< 0.001) for both situations. The glass fiber post showed the lowest concentrations of stress on both loads (p< 0.001). The carbon fiber post presented significant difference compared to the cast metal post, only in the oblique load (p=0.007). The diameter did not increase the stress of the evaluated posts (p=0.302). Conclusion: The fiber posts were more favorable for restoration of endodontically treated teeth; the increase of diameter did not influence the increase of tension; the oblique load was more harmful for both posts and tooth structure.

Introdução: O comportamento biomecânico de dentes tratados endodonticamente é variável conforme o material restaurador selecionado e situação do dente a ser restaurado. Objetivo: Analisar por meio do método dos elementos finitos bidimensional o comportamento biomecânico de diferentes retentores intrarradiculares e diâmetros em dentes com 2mm de remanescente coronário. Material e método: Foram confeccionados seis modelos com três tipo de retentores: pino de fibra de vidro, pino de fibra de carbono e núcleo metálico fundido, ambos com diâmetro #1 (1,1mm de diâmetro) e #2 (1,3mm de diâmetro). A modelagem foi realizada através do programa Rhinoceros 4.0, e em seguida nos programas FEMAP 10.2 e NeiNastran 9.2 para desenvolvimento d os modelos de elementos finitos. Nos carregamentos foram utilizadas forças de 100N axial e oblíquo. Os resultados foram visualizados pelo mapa de tensão von Mises, e pela análise de variância (ANOVA) e pós-teste Tukey, com nível de significância à 5%. Resultado: O carregamento oblíquo apresentou maiores valores de tensões (p< 0,001). O pino de fibra de vidro apresentou menores concentrações de tensões em ambos os carregamentos (p< 0,001). O pino de fibra de carbono apresentou diferença significativa em relação ao núcleo metálico somente no carregamento oblíquo (p=0,007). O diâmetro não influenciou para o aumento de tensões dos retentores avaliados (p=0,302). Conclusão: Os pinos de fibras são mais favoráveis para restaurações de dentes tratados endodonticamente; O aumento do diâmetro não influenciou no aumento de tensões; A carga oblíqua é mais prejudicial à tanto para o retentor quanto para a estrutura dentária.

Systemic Trans- and Postoperative Evaluations of Patients Undergoing Dental Implant Surgery

OBJECTIVE: The aims of this study were to examine the trans- and postoperative systemic characteristics of patients undergoing dental implant surgery and to investigate the relationship between pre- and post- surgery anxiety levels. MATERIAL AND METHODS: Thirty-nine patients were analyzed in 3 call centers to determine anxiety levels, pain levels, and preoperative and postoperative histories using the State-Trait (STAI) questionnaire. RESULTS: A total of 93 dental implants were installed, with a success rate of 100%. The most frequently reported systemic disease was hypertension. There was a significantly higher rate of effective clamping (torque) to the mandibular bone than to the maxillary bone. The association between postoperative surgical complications and longer operative time was not significant, but there was a significant correlation between the alteration of mouth opening and daily routine activities and a significant decrease in anxiety levels between the day of surgery and the postoperative time point (p =0.006). CONCLUSION: A longer surgical time was associated with surgery-related complications and with a higher anxiety index on the preoperative evaluation.

Análise das tensões em diferentes conexões de implante/ abutment / Stress analysis in different implant/abutment connections

O objetivo deste estudo foi comparar, por meio de uma análise fotoelástica, as tensões geradas na região peri-implantar dos implantes com diferentes conexões protéticas. Foram confeccionados 4 modelos em resina fotoelástica com implante unitário e coroa em alturas padronizadas. Mod 1: Hexágono Externo; Mod 2: Hexágono Interno; Mod 3: Cone-Morse e Mod 4: Corpo-único. Foi aplicada uma carga de 100N, tanto axial quanto obliquamente (45°) por meio da máquina de ensaio universal. O carregamento foi realizado em pontos fixos padronizados na superfície oclusal. Os resultados foram registrados fotograficamente por meio de uma câmera digital e analisados de forma qualitativa com auxílio do Adobe Photoshop. Tanto no carregamento axial quanto no carregamento oblíquo, observou-se que o implante de corpo-único apresentou a maior quantidade de franjas, ao contrário dos implantes de conexão interna. A diferença encontrada entre os modelos, quando da variação do sentido da carga, ocorreu devido ao fato de na carga oblíqua haver um maior número de franjas, e essas se concentram não só na região apical mas também do lado oposto à aplicação da carga, na região cervical. Concluiu-se que os implantes de conexão interna apresentaram a situação biomecânica mais favorável e os implantes de corpo-único apresentaram a maior concentração de tensões... (AU)

The aim of this study was to compare, by means of aphotoelastic analysis, the stresses generatedin the periimplantar regionof different implant/abutment connections. 4 modelswere fabricatedinphotoelastic resinwithsingle dental implantandstandardheight crowns. Mod 1: External Hexagon; Mod 2: Internal Hexagon; Mod 3: Morse-Taper and Mod4: One-Piece. It were applieda 100N axial and oblique (45°) loading by means of a universal testing machine. The loadwas appliedat standardized points on the occlusal surface. The results were recordedphotographicallyusinga digital camera andanalyzed qualitativelywiththeaid of the AdobePhotoshop software. Both inaxial and in the oblique loading, it was observed that one-piece implantshowed the highest number of fringes, apart from the internal connection implants. The differencebetween the models,whenthedirection of the load was changed, occurred duetotheoblique loading that caused greaternumber of fringes concentrated not onlyin the apical region, but also in the opposite side of the load application in the cervical region. It was concluded thattheinternal connection implants presented themost favorablebiomechanical situationand the one-piece implant presented the higheststress concentration... (AU)

Effect of the Parafunctional Occlusal Loading and Crown Height on Stress Distribution

The aim of this study was to assess, by the three-dimensional finite element method, the influence of crown-to-implant ratio and parafunctional occlusal loading on stress distribution in single external hexagon implant-supported prosthesis. Computer-aided design software was used to confection three models. Each model was composed of a block bone and an external hexagon implant (5x10.0 mm) with screw-retained implant prostheses, varying the height crown: 10, 12.5 and 15 mm. Finite element analysis software was used to generate the finite element mesh and to establish the loading and boundary conditions. Normal (200 N axial and 100 N oblique load) and parafunctional forces (1,000 N axial and 500 N oblique load) were applied. The results were visualized by von Mises and maximum principal stress. In comparison with the normal occlusal force, the parafunctional occlusal force induced an increase in stress concentration and magnitude on implant (platform and first threads) and screw (neck). The cortical bone showed the highest tensile stress under parafunctional force (oblique load). The stress concentration increased as the crown height increased. It was concluded that: increasing the C/I increased stress concentration in both implant components and cortical bone; parafunctional loading increased between 4-5 times the value of stresses in bone tissue compared with functional loading; the type of loading variation factor is more influential than the crown-to-implant factor.

O objetivo deste estudo foi avaliar, através do método dos elementos finitos tridimensionais, a influência do carregamento oclusal parafuncional e da altura da coroa na distribuição das tensões em próteses unitárias implantossuportadas de hexágono externo. Foram confeccionados três modelos com o auxílio de programas de desenho assistido. Cada modelo foi composto por um bloco ósseo da região molar mandibular, por um implante de tipo hexágono externo (5x10,0 mm) e por coroa com diferentes alturas: 10, 12,5 e 15 mm. Os modelos foram exportados para o programa de elementos finitos NEiNastran 9.0, para geração das malhas e estabelecer as condições de contorno. Aplicou-se uma carga funcional (200 N axial e 100 N oblíqua), bem como uma carga parafuncional (1.000 N axial e 500 N oblíqua). Os resultados foram visualizados por meio de mapas de Tensão de von Mises e mapas de Tensão Máxima Principal. O carregamento parafuncional induziu um aumento da área de distribuição e da magnitude das tensões no implante (plataforma e primeiras roscas) e parafuso (pescoço) em comparação com o carregamento funcional. A cortical óssea apresentou maiores áreas de tensão por tração sob carregamento parafuncional oblíquo. A concentração de tensões aumentou à medida que aumentou a altura da coroa. O aumento da altura da coroa induziu um aumento na concentração de tensões, tanto nos componentes do implante, quanto na cortical óssea; o carregamento parafuncional induziu um aumento entre 4-5 vezes da magnitude das tensões no tecido ósseo; o tipo de carregamento apresenta-se como um fator de variação mais influente do que a proporção coroa/implante.

O uso de drogas anticoagulantes e antiplaquet rias orais em pacientes cir£rgico-ambulatoriais – revisÆo de literatura / The use of anticoagulants and oral antiplatelet drugs in outpatient surgical patients – literature review

Os anticoagulantes orais (AOC) e antiagregantes plaquet rios sÆo drogas utilizadas para a preven‡Æo de fen“menos tromboemb¢licos, como tromboembolismo pulmonar em pacientes com fibrila‡Æo atrial e/ou v lvulas card¡acas, trombose e embolismo pulmonar. Para pacientes submetidos a procedimentos cir£rgico-odontol¢gico eram solicitados a interromperem o uso dos anticoagulantes at‚ que o valor do INR se mantivesse ≤que 2.0, de modo a evitar hemorragias no trans e p¢s-operat¢rio. No entanto, a interrup‡Æo do AOC pode causar a forma‡Æo de um co gulo, levando a obstru‡Æo das vias sangu¡neas. Sendo assim, tornava-se duvidosa a interrup‡Æo do medicamento para a realiza‡Æo de cirurgias odontol¢gicas, em que medidas hemost ticas locais seriam suficientes para promover hemostasia. Deste modo, o objetivo da revisÆo foi avaliar o risco de hemorragia em pacientes usu rios de AOC que sÆo submetidos a procedimentos cir£rgicos, por meio de um levantamento bibliogr fico realizado em estudos cl¡nicos relevantes publicados entre 1990 e 2012, pela base Medline/PubMed. Nesta revisÆo de literatura concluiu- se que o benef¡cio da preven‡Æo de tromboembolismo supera o risco de hemorragia, assim sendo, recomenda-se manter a dose da terapia com anticoagulantes inalterada para pacientes submetidos … cirurgia oral menor e Implantodontia, utilizando n¡veis de INR adequado, com aux¡lio de hemost tico locais. Al‚m disto, uma t‚cnica cir£rgica apurada deve ser realizada nestes pacientes. Com rela‡Æo … cirurgia oral mais invasiva com risco de hemorragia, pode ser necess rio o tratamento em conjunto com a equipe m‚dica.

The oral anticoagulants (AOC) and platelet antiagregants are drugs used for the prevention of thromboembolic phenomena, such as pulmonary embolism in patients with atrial fribrilation heart valves, thrombosis and pulmonary embolism. For patients who are undergoing surgical procedures-dentistry were asked to discontinue the use of anticoagulants until the value of the INR remained≤2.0, that in order to avoid trans and hemorrhages in the postoperative period. However, the AOC can cause the formation of a clot, leading to obstruction of blood pathways. Thus, it became doubtful the medicine for surgery, in which local hemostatic measures would be sufficient to promote hemostasis. Thus, the objective of the review was to evaluate the risk of bleeding in patients AOC users that are subjected to surgical procedures, through a bibliographical survey carried out in relevant clinical studies published between 1990 and 2012, by the MedlinePubMed data. In this review of literature was concluded that the benefit of thromboembolism prevention overcomes the risk hemorrhage, therefore, it is recommended to keep the dose of anticoagulant therapy unchanged for patients undergoing oral surgery and implant dentistry, using appropriate INR levels with the assistance of local hemostatic. In addition, a refined surgical technique should be performed in these patients. With respect to the most invasive oral surgery, with a risk of bleeding, treatment may be necessary in conjunction with the medical staff.

O tratamento da apneia obstrutiva do sono e a utilização de implantes osseointegráveis - revisão de literatura / The treatment of obstructive sleep apnea and dental implants use - literature review

A síndrome da apneia obstrutiva atinge milhões de pessoas ao redor do mundo. Os aparelhos reposicionadores da mandíbula têm sido indicados nos casos de grau leve/moderado da síndrome, entretanto, nos pacientes edêntulos a sua utilização é deficiente, pois não há retenção. Assim, o objetivo deste estudo foi realizar uma revisão sob a utilização deste método de tratamento quando utilizado simultaneamente aos implantes osseointegráveis. Realizou-se uma revisão nas bases de dados Medline/PubMed, ISI, Cochrane, Dentistry Oral Science, Clinical Trials, Controlled Trials e Bireme-Bvs sobre o tema dental implant / sleep apnea syndrome, e localizou-se 22 artigos. Após avaliação sob os critérios de inclusão, selecionou-se 2 estudos e complementou-se a revisão com uma análise de estudos randomizados e controlados nas sete bases anteriores com os unitermos: sleep apnea syndrome and appliance oral and randomized controlled Trial, e 37 artigos foram localizados que, após os critérios de inclusão, selecionou-se 17. Os estudos abordando a utilização de implantes osseointegráveis como meio coadjuvante na estabilização de aparelhos reposicionadores da mandíbula são escassos, e são do tipo caso clínico que apontam efetividade na técnica. Os estudos analisando o efeito desses aparelhos em pacientes dentados indicam melhoria nos níveis de apneia e ronco. A utilização de aparelhos reposicionadores mandibulares em pacientes dentados é uma técnica efetiva em pacientes com síndrome da apneia obstrutiva leve/moderada. São necessários estudos com controle e randomizados para analisar a utilização de aparelhos de reposição mandibular com auxílio de implantes osseointegráveis nesta década.

The obstructive sleep apnea syndrome affects millions of people around the world. The mandibular repositioning devices have been indicated in cases of mild/moderate syndrome; however in edentulous patients its use is deficient since there is no retention. Therefore the objective of this study was to conduct a review on the use of this treatment method combined to osseointegrated implants. A search on the theme: Dental implant and sleep apnea syndromewas performed in the Medline/PubMed, ISI, Cochrane, Dentistry Oral Science, Clinical Trials, Controlled Trials, and Bireme-BvS, databases, and 22 articles were found. After an evaluation 2 studies were selected and the review was complemented with an analysis of randomized controlled trials in the previous seven bases using the key-words: Sleep apnea syndrome, Oral appliance and Randomized controlled trial. The search returned 37 articles, and after they were submitted to inclusion criteria 17 studies were selected. There are a small number of studies presenting the use of dental implants as a mean to assist the stabilization of the mandibular repositioning appliances; those that are available are case reports that focusing on the effectiveness of the technique. Studies examining the effect these appliances in dentate patients indicate improvement in the levels of apnea and snoring. The use of mandibular repositioning appliances in dentate patients is an effective technique in treatment of patients with obstructive sleep apnea syndrome mild/moderate. Randomized controlled trials are required in order to enable an analysis of the use of mandibular repositioning devices with the aid of dental implants

Comportamento biomecânico dos sistemas de retenção de overdentures / Biomechanical behavior of attachment systems for overdentures

Objetivo: deste trabalho foi comparar as tensões transmitidas ao osso peri-implantar em diferentes sistemas de retenções de overdentures mandibulares e maxilares retidas por implantes. Material e métodos: a busca dos trabalhos publicados foi realizada na base de dados PubMed/Medline, entre janeiro de 2002 e agosto de 2014. A seleção dos estudos relevantes foi realizada de acordo com os critérios de inclusão e exclusão. Os dados foram extraídos por dois revisores independentes. Resultados: um total de 140 artigos foi encontrado, sendo que, após a aplicação dos critérios de inclusão e exclusão, foram selecionados 21 artigos. Oito estudos utilizaram extensiometria, cinco avaliaram as tensões por meio da fotoelasticidade e sete realizaram elementos finitos. Apenas um estudo in vivo foi selecionado. O sistema de retenção mais comumente avaliado foi o O-ring (18/21). O sistema O-ring individualizado distribuiu melhor as forças para o tecido ósseo peri-implantar, quando comparado com o sistema barra-clipe. Conclusão: o presente estudo não encontrou evidências suficientes a respeito do melhor mecanismo de retenção de overdentures. As metodologias testadas nos estudos selecionados devem ser validadas por outras análises complementares e utilizadas como guia para a realização de estudos clínicos futuros.

Objective: to the purpose of this study was to compare the stress distribution in the peri-implant hard tissue on different attachment systems for mandibular or maxillary implant-retained overdentures. Material and methods: the search for published studies was performed on PubMed/Medline database covering the period of January 2000 to April 2014. The selection of the eligible studies was performed according to including and excluding criteria. Results: a total of 140 studies were screened and according to the search strategy, 21 studies were selected for this review. Eight studies perfomed strain-gauge analysis, 5 evaluated the stress distribution though photoelastic test and 7 performed tridimensional fi nite element analysis. Only one study in vivo was included. Non-splinted O-rings showed better stress distribution than other bar-clip attachment systems. Conclusions: the present study did not fi nd suffi cient evidences regarding the most indicated attachment system for overdentures with better stress distribution for the peri-implant hard tissue. The methodologies analyzed should be complemented with other tests and used as a tool for further clinical studies.

Reações alérgicas aos implantes osseointegráveis de titânio / Allergic reactions to titanium dental implants: a literature review

Os implantes de titânio vêm sendo rotineiramente utilizados na clínica, aumentando proporcionalmente os casos de reações alérgicas a este material. Objetivos: alertar os cirurgiões-dentistas e especialistas sobre este fenômeno a partir da revisão da literatura. Material e métodos: foram incluídos trabalhos na língua inglesa publicados de janeiro de 1990 a maio de 2013, usando-se as palavras-chave “implantes dentários”, “titânio” e “alergia”, envolvendo casos clínicos e estudos experimentais/clínicos relacionados estritamente aos implantes dentários de titânio. Artigos escritos em outras línguas e textos como cartas ao editor foram excluídos. Resultados: dos 22 artigos recuperados, apenas sete foram considerados, sendo 4 casos clínicos e 3 de estudos experimentais. Nos casos clínicos, as lesões encontradas foram: edema, lesão eritematosa, queilite exfoliativa, eczema facial e bucal. Nos estudos experimentais, urticária e dermatite foram encontradas. O menor tempo de manifestação da sintomatologia variou entre uma semana e seis meses. O teste de Patch não foi realizado em dois trabalhos clínicos. Apenas um estudo verificou histologicamente a ausência de reação alérgica. Conclusão: dentro dos limites da literatura disponível, a alergia ao titânio é extremamente rara e parece estar relacionada ao gênero feminino. Mais estudos experimentais controlados são necessários para responder esta questão.

Titanium dental implants have been common practice in the dental office, which can increases the number of allergic reactions to this material. Objectives: to alert dental surgeons and specialists of this possible phenomenon through a literature review. Material and methods: an electronic search at PubMed was performed with the keywords “dental implants”, “titanium”, and “allergy” from January 1990 to May 2013. Only articles published in the English language were included. Letters to editor were excluded. Results: from the 22 initially retrieved articles, only 7 were included, being 4 clinical case reports and 3 experimental studies. For clinical cases, the reactions included edema, erythema, exfoliative cheilitis, and eczema. Regarding experimental studies, skin rash and dermatitis were reported. A patch test was not used in two clinical reports. Only one study used histological analysis to attest the lack of allergic reactions. Conclusion: within the limits of the available literature, allergic reactions to titanium dental implants are extremely rare and seem to be related to the female gender. More controlled clinical studies are necessary to elucidate this question.

Efeito do carregamento funcional e parafuncional em próteses unitárias implantossuportadas com diferentes plataformas protéticas: análise 3D por elementos finitos / Effect of functional and parafunctional loading on single-tooth implant-supported prostheses with different prosthetic platforms: a 3-D finite element analysis

Objetivo: analisar a influência do carregamento oclusal parafuncional e da conexão protética na distribuição das tensões no tecido ósseo, utilizando o método de elementos finitos tridimensionais. Material e métodos: cada modelo foi composto por um bloco ósseo da região molar mandibular, com um implante do tipo hexágono externo ou cone-morse (5 mm x 10 mm), e as respectivas coroas metalocerâmicas unitárias parafusadas e cimentadas (altura da coroa: 12,5 mm). A camada de cimento foi construída com 30 μm de espessura. Uma carga funcional (quatro pontos, 200 N axial, 100 N oblíqua) e uma parafuncional (dois pontos, 1.000 N axial, 500 N oblíqua) foram aplicadas, e os resultados visualizados por meio de mapas de von Mises e tensão máxima principal. Resultado: o carregamento parafuncional produziu aumento da concentração e magnitude das tensões, principalmente sob carga oblíqua. A conexão cone-morse proporcionou uma área maior de distribuição de tensões no implante, ao nível da junção implante/parafuso. O parafuso do implante cone-morse apresentou maiores tensões ao nível do pescoço, principalmente no carregamento parafuncional. No osso cortical, as tensões por tração e por compressão localizaram-se ao redor da plataforma e ao nível da primeira rosca do implante em ambos os implantes, e em maior área na conexão externa. Conclusão: 1) Em relação ao osso, o implante cone-morse apresentou a situação biomecânica mais favorável sob ambos os tipos de carregamento e de direção da carga; 2) O carregamento parafuncional induziu ao aumento na magnitude das tensões nas estruturas analisadas.

A 3-D Finite Element Study of the Influence of Crown-Implant Ratio on Stress Distribution

The purpose of this study was to assess the influence of the crown height of external hexagon implants on the displacement and distribution of stress to the implant/bone system, using the three-dimensional finite element method. The InVesalius and Rhinoceros 4.0 softwares were used to generate the bone model by computed tomography. Each model was composed of a bone block with one implant (3.75x10.0 mm) with external hexagon connections and crowns with 10 mm, 12.5 mm and 15 mm in height. A 200 N axial and a 100 N oblique (45°) load were applied. The models were solved by the NeiNastran 9.0 and Femap 10.0 softwares to obtain the results that were visualized by maps of displacement, von Mises stress (crown/implant) and maximum principal stress (bone). The crown height under axial load did not influence the stress displacement and concentration, while the oblique loading increased these factors. The highest stress was observed in the neck of the implant screw on the side opposite to the loading. This stress was also transferred to the crown/platform/bone interface. The results of this study suggest that the increase in crown height enhanced stress concentration at the implant/bone tissue and increased displacement in the bone tissue, mainly under oblique loading.

A proposta deste estudo foi avaliar a influência da altura da coroa de implantes de hexágono externo sobre o deslocamento e distribuição de tensões para o sistema implante/osso utilizando o método de elementos finitos. Os softwares InVesalius e Rhinoceros 4.0 foram usados para gerar o modelo de osso por meio de uma tomografia computadorizada. Cada modelo foi composto de um bloco ósseo com um implante (3.75 x 10.0 mm) com conexão de hexágono externo e coroas de 10 mm, 12.5mm e 15 mm em altura. Uma carga axial de 200 N e oblíqua (45°) de 100 N foram aplicadas. Os modelos foram resolvidos pelo software NeiNastram 9.0 e Femap 10.0 para obtenção dos resultados que foram visualizados por meio de mapas de deslocamento, de von Mises (coroa/implante) e tensão máxima principal (osso). A altura da coroa sob carga axial não influenciou o deslocamento e concentração de tensões, enquanto que a carga oblíqua aumentou a ação destes fatores. A maior concentração de tensões foi observada no pescoço do parafuso do implante no lado oposto à aplicação de carga. Esta tensão foi transferida para a interface coroa/plataforma/interface óssea. Os resultados deste estudo sugerem que o aumento da coroa amplia a concentração de tensões no tecido ósseo/implante, aumentando o deslocamento no tecido ósseo, principalmente sob carga oblíqua.