Mechanical Behavior of One-Piece and Two-Piece Tapered Prosthetic Abutments with 11.5 and 16 Degrees.

The objective of this study is to examine the mechanical behavior of two-piece abutments (Morse taper with 16° internal angulation and Morse taper with 11.5° internal angulation) before and after cyclic fatigue testing, following ISO 14801:2016 guidelines. The specimens were divided into three groups: a modified Morse taper with a taper angle of 16° (GM group), a conventional Morse taper (taper angle of 11.5° deg) with a two-piece (CMt group), and one-piece abutments (CMo group). Each experimental group was formed by ten implants and ten abutments (n = 10) for a total of 30 specimens (n = 30). The abutments were tightened and loosened, and a fatigue test was applied with 15 Hz and 5 × 106 cycles. Subsequently, the abutments were loosened, and a pull-out test was performed on the CMt group. Finite element analysis (FEA) was conducted on stress concentration regions. The statistical analysis of the loosening test was performed using two-way ANOVA and Tukey's tests (p < 0.05) to compare screw loosening within each group and between the groups with and without mechanical fatigue. Significant differences were found among the three groups in the loosening test when analyzing the values with and without fatigue (p < 0.001) within each group. When the groups were compared with each other, there was also a significant difference between them (p < 0.001), except between groups GM and CMt without fatigue (p = 0.840). In the pull-out test of the CMt group, the sample exhibited frictional locking only after fatigue (mean = 94.2 N). The FEA demonstrated a varied stress distribution in all groups. The stress was found to be more concentrated in the upper third and middle third regions of the implant, as well as in the opposite region of the load application for all three groups. Although the CMo group showed lower rates of loosening, it displayed a poorer stress distribution in comparison to the GM and CMt groups. On the other hand, the CMt group exhibited a satisfactory frictional lock after undergoing the fatigue tests.

Immediate prosthetic rehabilitation of lower molars with hybrid internal tapered implants: report of two cases / Reabilitação protética imediata de molares inferiores com implantes cônicos internos híbridos: relato de dois casos

ABSTRACT The immediate rehabilitation of the posterior region of the mandible with dental implants, expands the set of possible actions for the dental surgeon, in the face of tooth loss. The purpose of this study is to describe two cases of single rehabilitation of mandibular molars with hybrid internal tapered implants indicated for immediate loading in post-extraction socket, associated with the maintenance of the prosthetic and peri-implant space. Implants with macrogeometry and surface treatment (Hydrophilic) were used to optimize primary stability, as well as the type of internal connection and prosthetic abutments that allows better accommodation and healing of adjacent tissues, and protection of the bone graft. Different methodologies of surgical guides did not influence the final result. The predictability of associating techniques and components can be observed in the 2-year follow-up. The initial planning combined with the new technologies enable to achieve stable and functional final restorations.

RESUMO A reabilitação imediata da região posterior da mandíbula com implantes dentários, amplia o conjunto de ações possíveis ao cirurgião dentista, frente as perdas dentárias. O intuito desse estudo é descrever dois casos de reabilitação unitária de molares inferiores com implantes cônicos internos híbridos indicados para carregamento imediato em alvéolos pós-extração, associado a manutenção do espaço protético e peri-implantar. Foram utilizados implantes com macrogeometria e tratamento de superfície que otimizassem a estabilidade primária (Hidrofílicos), bem como o tipo de conexão interna e abutments protéticos que permitisse melhor acomodação e cicatrização dos tecidos adjacentes, e proteção do enxerto ósseo. Diferentes metodologias de guias cirúrgicos não influenciaram o resultado final. A previsibilidade da associação de técnicas e componentes pode ser observada no follow-up de 2 anos. O planejamento inicial aliado às novas tecnologias permite restaurações finais estáveis e funcionais.

Management of bruxism associated with temporomandibular disorder: case report / Manejo do Bruxismo associado a Disfunção Temporomandibular: relato de caso

ABSTRACT Studies have found the association between episodes of bruxism and the presence of signs and symptoms of temporomandibular disorder (TMD). The aim of the present study was to report the diagnosis and palliative therapy of bruxism associated with TMD. Patient, 23 years old, male gender, presented at dental clinic, complaining of pain in the temporomandibular joint on the left side and alteration of the form of the anterior teeth. During the anamnesis it was documented that this symptom was recurrent and reported the habit of grinding teeth. The clinical examination observed discrepancy between the centric relation and the maximum habitual intercuspation, unsatisfactory protrusive guide, presence of wear facets, clicking and mandibular deviation during mouth opening. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC / TMD) questionnaire was applied to diagnose TMD. By means of specific algorithms this disorder was classified as myofascial pain, disc displacement with reduction and osteoarthritis, all affecting the left side. Thus, it was proposed the assembly of the models in semi-adjustable articulator for occlusal mapping and waxing diagnosis, then the occlusal adjustment by selective wear and material addition was executed. After this procedure, the occlusal splint was installed as a palliative therapy for bruxism. This case report suggests that the dental approach by means of occlusal adjustment and occlusal splint, in a patient diagnosed with bruxism and temporomandibular disorder, reduces the signs and symptoms that affect the components of the Stomatognathic System.

RESUMO Estudos tem encontrado a associação entre os episódios de bruxismo e a presença dos sinais e sintomas de disfunção temporomandibular (DTM). O objetivo do presente trabalho foi relatar o diagnóstico e terapia paliativa do bruxismo associado à DTM. Paciente, 23 anos, gênero masculino, apresentou-se à clínica odontológica, queixando-se de dor na articulação temporomandibular do lado esquerdo e alteração da forma dos dentes anteriores. Durante a anamnese foi documentado que esse sintoma era recorrente e relatado o hábito de ranger os elementos dentais. No exame clínico observou-se discrepância entre relação cêntrica e máxima intercuspidação habitual, guia protrusiva insatisfatória, presença de facetas de desgaste, estalido e desvio mandibular durante o movimento de abertura bucal. O questionário Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) foi aplicado para diagnosticar a DTM. Por meio de algoritmos específicos essa desordem foi classificada como dor miofascial, deslocamento de disco com redução e osteoartrite, todos acometendo o lado esquerdo. Desta forma, foi proposto a montagem dos modelos em articulador semi-ajustável para mapeamento oclusal e enceramento diagnóstico. Em seguida o ajuste oclusal por desgaste seletivo e acréscimo de material foi executado. Finalizado esse procedimento, a placa estabilizadora da oclusão foi instalada como terapia paliativa para o bruxismo. Esse relato de caso sugere que a abordagem odontológica por meio do ajuste oclusal e placa oclusal, em paciente diagnosticado com bruxismo e disfunção temporomandibular, reduz os sinais e sintomas que afetam os componentes do Aparelho Estomatognático.

Effects of fractionation and ionizing radiation dose on the chemical composition and microhardness of enamel.

OBJECTIVE: To evaluate the chemical and mechanical properties of enamel submitted to different in vitro radiation protocols. DESIGN: Third molars were divided into seven groups (n = 8): non-irradiated (NI); a single dose of 30 Gy (SD30), 50 Gy (SD50), or 70 Gy (SD70) of radiation; or fractional radiation doses of up to 30 Gy (FD30), 50 Gy (FD50), or 70 Gy (FD70). Hemisections were analysed by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS) and Knoop microhardness (KHN) test. One-way ANOVA followed by Bonferroni's post-hoc test compared the test groups with the NI. Two-way ANOVA was performed for the fractionation and radiation dose, followed by Bonferroni's test (α = 0.05). RESULTS: FTIR revealed differences for the amide I band between the NI and FD50 and NI and FD70 groups (p < 0.001). For the organic matrix/mineral ratio, the FD70 group presented a lower ratio compared to NI (p = 0.009). Excluding the NI group, there were differences between the FD30 and FD50 (p = 0.045) and the FD30 and FD70 groups (p < 0.001). For EDS, there were differences for Ca (p = 0.011) and Ca/P (p < 0.001), with the FD70 group presenting lower values compared to NI (p = 0.015; p < 0.001). For KHN, the FD70 group presented lower values than the NI (p = 0.002). Two-way ANOVA showed difference for the dose (p < 0.001), with the 70 Gy group presenting a lower KHN value within the fractionated groups. CONCLUSION: Fractional doses 70 Gy irradiation caused chemical and mechanical changes to enamel. Radiation applied in single or fractional doses produced different effects to enamel.

Head and neck cancer therapy-related oral manifestation management in the COVID-19 pandemic: a critical review.

With the onset of the new coronavirus disease (COVID-19) pandemic, the dental treatment of patients at risk of infection has become quite challenging. In view of this, patients with head and neck cancer may present with oral complications due to anticancer therapy, making dental assistance necessary. Thus, the objective of the study was to review the literature and critically discuss important concerns about the treatment of patients with head and neck cancer during the COVID-19 pandemic. Because dental professionals are in close contact with the main viral transmission routes, this study presents recommendations for management and protection during clinical dental care. The main characteristics and transmission routes of COVID-19 are also discussed. Dental professionals should control pain and the side effects of antineoplastic treatment and use preventive measures for infection control. During this pandemic, patients with head and neck cancer should not undergo elective procedures, even if they do not have symptoms or a history of COVID-19; therefore, in asymptomatic or painless cases, only preventive actions are recommended. In symptomatic or painful cases, precautions for safe interventional treatments must be implemented by following the hygiene measures recommended by health agencies and using personal protective equipment. During health crises, new protocols emerge for cancer treatment, and professionals must act with greater attention toward biosafety and updated knowledge. It is important to offer adequate individualized treatment based on the recommendations of preventative and interventional treatments so that patients can face this difficult period with optimized quality of life.

Changes in mandibular and articular dynamics associated with surgical versus nonsurgical treatment of mandibular condylar fractures: a systematic review with meta-analysis.

OBJECTIVE: The aim of this study was to evaluate the mandibular and articular dynamics and the presence of complications associated with surgical or nonsurgical treatments of condylar fractures. STUDY DESIGN: Clinical trials that compared open reduction internal fixation and maxillomandibular fixation in patients with condylar fractures were included. We performed an electronic search of PubMed, Scopus, Cochrane Library, Web of Science, and LILACS (Latin American and Caribbean Health Sciences) databases starting from February 2017 and updated in January 2019 and found 467 articles. We evaluated methodologic quality by using the criteria from Cochrane's Collaboration Tool. RESULTS: After independent screening of abstracts, we assessed the full texts of 88 articles; 9 studies were included for qualitative synthesis; but only 8 were included for the meta-analysis. Four studies were considered to have high risk of bias, and 5 were considered to have low risk. The risk ratio (RR = 0.20; 95% confidence interval [CI] 0.13-0.32) was observed for complications. The quality of evidence, using GRADE software, was considered low for maximum mouth opening and protrusive movement and moderate for lateral excursion movement and complications. CONCLUSIONS: This review suggested that open reduction internal fixation and maxillomandibular fixation are effective. However, surgical treatment presented higher objective parameters. Nonsurgical treatment presented a high index of complications, such as malocclusion, pain and deviation.

Head and neck cancer therapy-related oral manifestation management in the COVID-19 pandemic: a critical review

Abstract With the onset of the new coronavirus disease (COVID-19) pandemic, the dental treatment of patients at risk of infection has become quite challenging. In view of this, patients with head and neck cancer may present with oral complications due to anticancer therapy, making dental assistance necessary. Thus, the objective of the study was to review the literature and critically discuss important concerns about the treatment of patients with head and neck cancer during the COVID-19 pandemic. Because dental professionals are in close contact with the main viral transmission routes, this study presents recommendations for management and protection during clinical dental care. The main characteristics and transmission routes of COVID-19 are also discussed. Dental professionals should control pain and the side effects of antineoplastic treatment and use preventive measures for infection control. During this pandemic, patients with head and neck cancer should not undergo elective procedures, even if they do not have symptoms or a history of COVID-19; therefore, in asymptomatic or painless cases, only preventive actions are recommended. In symptomatic or painful cases, precautions for safe interventional treatments must be implemented by following the hygiene measures recommended by health agencies and using personal protective equipment. During health crises, new protocols emerge for cancer treatment, and professionals must act with greater attention toward biosafety and updated knowledge. It is important to offer adequate individualized treatment based on the recommendations of preventative and interventional treatments so that patients can face this difficult period with optimized quality of life.

Impact of Implant Number on Mandibular Implant-Supported Profile Prostheses: A Systematic Review.

PURPOSE: To assess studies on edentulous patients rehabilitated using mandibular implant-supported profile prostheses and analyze the impact of different numbers of implants used on the implant survival rate, peri-implant bone loss, and prosthesis survival rate. MATERIALS AND METHODS: This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement and was registered on PROSPERO. The PubMed/MEDLINE database was searched for articles published before July 18, 2016. The study attempted to answer the following PICO question: In edentulous patients, do full-arch fixed prostheses supported by three implants have a satisfactory implant survival rate, marginal bone loss, and prosthesis survival rate compared with those supported by different numbers of implants? Evidence levels of each study were evaluated using the Oxford Centre for Evidence-Based Medicine (OCEBM); methodologic quality was evaluated using the Methodological Index for Nonrandomized Studies (MINORS) scale and Cochrane Risk of Bias Tool. Descriptive statistics were performed when applicable. Implant survival curves were constructed using the Kaplan-Meier method, and marginal bone loss was analyzed using the Kruskal-Wallis, Dunn's, and Mann-Whitney tests. RESULTS: This analysis included 21 published studies of 4,712 implants and 1,245 mandibular implant-supported profile prostheses in 1,245 patients. The patients were grouped by the number of implants used: group 1 (three implants) had an implant survival rate of 90%; group 2 (four implants) had a rate of 95%; and group 3 (five implants) had the lowest rate, 74%. Groups 1 and 3 had the lowest first-year bone losses (median: 0.73 and 0.70 mm, respectively), and were significantly different from group 2 (median: 1.31 mm; P < .001). CONCLUSION: Despite the limitations in the studies with low levels of evidence and the methodology of MeSH term research, it was concluded that the implant survival rate and first-year bone loss of full-arch fixed prostheses supported by three implants were satisfactory. However, the prosthesis survival rate was inferior to that of other groups, which suggests a longer follow-up of these rehabilitations.

Effect of Occlusal Splints on the Stress Distribution on the Temporomandibular Joint Disc

Abstract Conservative approach, including occlusal splint therapy, is the first option to treat temporomandibular disorders (TMD), because of its reversibility. The present study analyzed the effect of the articular disc position and occlusal splints use on the stress distribution on this disc. A two-dimensional (2D) finite element (FE) model of the temporomandibular joint with the articular disc at its physiologic position was constructed based on cone-beam computed tomography. Three other FE models were created changing the disc position, according to occlusal splint use and anterior disc displacement condition. Structural stress distribution analysis was performed using Marc-Mentat package. The equivalent von Mises stress was used to compare the study factor. Higher stress concentration was observed on the intermediate to anterior zone of the disc, with maximum values over 2MPa. No relevant difference was verified on the stress distribution and magnitude comparing disc positions and occlusal splint use. However, there was stress reduction arising from the use of the occlusal splints in cases of anterior disc displacement. In conclusion, based on the generated FE models and established boundary conditions, the stress increased at the intermediate zone of the TMJ disc during physiological mandible closure. The stress magnitude was similar in all tested situations

Resumo Abordagens conservadoras, incluindo o uso de placas oclusais, são as primeiras opções de tratamento para disfunção temporomandibular (DTM), devido à sua reversibilidade. O presente estudo analisou o efeito da posição do disco articular e do uso de placa oclusal na distribuição de tensões no disco. Um modelo bidimensional (2D) de articulação temporomandibular (ATM) em posição fisiológica, foi desenvolvido para análise pelo método de elementos finitos, baseado em imagens de tomografia computadorizada do tipo cone-beam. Três outros modelos foram criados alterando a posição do disco de acordo com o uso de placa oclusal e condição de deslocamento anterior do disco. Uma análise estrutural da distribuição de tensões foi realizada no software Marc-Mentat, e equivalente Von Mises foi usado para comparar os fatores em estudo. Maior concentração de tensão foi observada na zona intermediária para a zona anterior do disco, atingindo valores máximos acima de 2 MPa. Nenhuma diferença relevante foi verificada na localização e magnitude das tensões quando comparadas as posições do disco e uso de placa oclusal. No entanto, houve pequena redução das tensões decorrente do uso de placa oclusal em caso de deslocamento anterior do disco. Conclui-se que mediante os modelos criados e condições de contorno estabelecidas, as tensões na zona intermediária do disco aumentam durante o fechamento mandibular fisiológico. A magnitude das tensões foi semelhante em todas as situações testadas

Degree of conversion and bond strength of resin-cements to feldspathic ceramic using different curing modes

Abstract Resin cements have led to great advances in dental ceramic restoration techniques because of their ability to bond to both dental structures and restorative materials. Objective The aim of this study was to assess the performance of resin cements when different curing modes are used, by evaluating the degree of conversion and bond strength to a ceramic substrate. Material and Methods Three resin cements were evaluated, two dual-cured (Variolink II and RelyX ARC) and one light-cured (Variolink Veneer). The dual-cured resin cements were tested by using the dual activation mode (base and catalyst) and light-activation mode (base paste only). For degree of conversion (DC) (n=5), a 1.0 mm thick feldspathic ceramic disc was placed over the resin cement specimens and the set was light activated with a QTH unit. After 24 h storage, the DC was measured with Fourier transform infrared spectroscopy (FTIR). For microshear bond strength testing, five feldspathic ceramic discs were submitted to surface treatment, and three cylindrical resin cement specimens were bonded to each ceramic surface according to the experimental groups. After 24 h, microshear bond testing was performed at 0.5 mm/min crosshead speed until the failure. Data were submitted to one-way ANOVA followed by Tukey test (p<0.05). Scanning electron microscopy (SEM) was used for classifying the failure modes. Results Higher DC and bond strength values were shown by the resin cements cured by using the dual activation mode. The Variolink II group presented higher DC and bond strength values when using light-activation only when compared with the Variolink Veneer group. Conclusion The base paste of dual-cured resin cements in light-activation mode can be used for bonding translucent ceramic restorations of up to or less than 1.0 mm thick.

Effect of Occlusal Splints on the Stress Distribution on the Temporomandibular Joint Disc.

Conservative approach, including occlusal splint therapy, is the first option to treat temporomandibular disorders (TMD), because of its reversibility. The present study analyzed the effect of the articular disc position and occlusal splints use on the stress distribution on this disc. A two-dimensional (2D) finite element (FE) model of the temporomandibular joint with the articular disc at its physiologic position was constructed based on cone-beam computed tomography. Three other FE models were created changing the disc position, according to occlusal splint use and anterior disc displacement condition. Structural stress distribution analysis was performed using Marc-Mentat package. The equivalent von Mises stress was used to compare the study factor. Higher stress concentration was observed on the intermediate to anterior zone of the disc, with maximum values over 2MPa. No relevant difference was verified on the stress distribution and magnitude comparing disc positions and occlusal splint use. However, there was stress reduction arising from the use of the occlusal splints in cases of anterior disc displacement. In conclusion, based on the generated FE models and established boundary conditions, the stress increased at the intermediate zone of the TMJ disc during physiological mandible closure. The stress magnitude was similar in all tested situations.

Predictors of success for mandibular repositioning appliance in obstructive sleep apnea syndrome

Abstract The characteristics of non-obese patients with mild to moderate Obstructive Sleep Apnea Syndrome (OSAS) who will present with a good response to Mandibular Repositioning Appliance (MRA) treatment have not yet been well established in the literature. The aim of this study is to assess whether polysomnographic (PSG), demographic, anthropometric, cephalometric, and otorhinolaryngological parameters predict MRA success in the treatment of OSAS. Forty (40) males with mild and moderate OSAS were assessed pretreatment and 2-months post-treatment after wearing an MRA. Demographic, anthropometric, otorhinolaryngological (ENT), cephalometric, and polysomnographic parameters, including continuous positive airway pressure (CPAP) titrated pressure, dental models, Epworth Sleepiness Scale, quality of life (Short Form SF-36), and mood state (Profile of Mood States – POMS), were assessed. The responders exhibited fewer oropharyngeal alterations, increased upper pharyngeal space, reduced lower airway space, and increased mandibular intercanine width, and they had milder disease. Nevertheless, no predictive factors of MRA success could be found. MRA was more successful among men with a more pervious airway, a larger interdental width and milder OSAS. However, a combined [1] functional and structural assessment is needed to successfully predict the [2] effectiveness of MRA treatment of OSA.

Associação de cerâmicas na reabilitação estética do sorriso ­ utilização de cerâmica reforçada por dissilicato de lítio e cerâmica feldspática / Ceramics association in smile aesthetic rehabilitation ­ the use of ceramics reinforced by disilicate lithium and feldspar ceramic

A demanda de pacientes que buscam por tratamentos estéticos dos dentes anteriores está em constante crescimento. A busca incessante pelo desenvolvimento de novos materiais e técnicas odontológicas, visando procedimentos mais conservadores do elemento dental e resultado mais previsível, com excelentes propriedades estéticas e funcionais, tem levado as restaurações dos dentes anteriores a um novo patamar. As cerâmicas têm sido muito estudadas e, com isso, melhoras significativas nas suas propriedades mecânicas e estéticas foram obtidas. Associado a isso, o aperfeiçoamento de técnicas adesivas tornou possível a confecção de peças cerâmicas menos espessas, sem a necessidade de grandes desgastes da estrutura dentária. O aprimoramento do diagnóstico e o planejamento reverso possibilitaram resultados bastante previsíveis. Nesse contexto, o relato de caso apresentado neste artigo descreve a sequência clínica de reabilitação estética dos dentes 11, 12, 21 e 22 empregando facetas indiretas de cerâmica reforçadas por dissilicato de lítio associadas à aplicação de cerâmica feldspática, buscando a reprodução das características naturais dos dentes. O conhecimento da técnica operatória, dos materiais restauradores e a qualidade do trabalho protético são fundamentais para se obter um resultado estético e funcional de excelência (AU).

The number of patients seeking for aesthetic treatments of the anterior teeth is constantly growing. The incessant search for the development of new dental materials and techniques, aiming more conservative procedures of the dental element and more predictable results with excellent aesthetic and functional properties, has led the restoration of anterior teeth to a new level. Ceramics have been studied and thus significant improvements in their mechanical and aesthetic properties were obtained. Associated with this, the improvement of adhesive techniques has made possible the production of thinner ceramic parts without the need of large wear of the tooth structure. Improved diagnosis and reverse planning allowed fairly predictable results. In this context, the case report presented in this article describes the clinical sequence of aesthetic restoration of teeth 11, 12, 21 and 22 employing indirect pottery facets reinforced by lithium disilicate associated with application of feldspar ceramic seeking reproduction of the natural characteristics of teeth. The Knowledge of surgical techniques, restorative materials and the quality of prosthetic work are fundamental to get aesthetic and functional results of excellence (AU).

Congenital oral synechia and ankyloblepharon filiforme adnatum: Case report and literature review.

INTRODUCTION: Congenital intraoral synechias are adhesions of intraoral structures involving soft tissue. These conditions and another anomaly called ankyloblepharon filiforme adnatum, which is partial fusion of the eyelid margins by bands of tissue, are rarely reported in the literature. The association of both anomalies of the craniomaxillofacial region is an even more unusual finding. PURPOSE: This article adds more information to the literature by reporting a case of a neonate with a rare association of bilateral synechia between the jaws, fusion of buccal mucosa to the ridges and between the tongue and palate, and ankyloblepharon filiforme adnatum in both eyes, without any other facial or systemic malformation. METHODS: A literature review of similar cases published in PUBMED/MEDLINE was conducted followed by a discussion and comparison to the new case. CONCLUSION: The rare association of these congenital defects, without the presence of syndromic symptoms, could be diagnosed and treated easily with good prognostic evolution.

Bisphosphonate treatment and dental implants: A systematic review

BACKGROUND: To analyze articles that studied patients submitted to diphosphonates therapy and who received dental implants before, during or after bisphosphonate (BP) treatment, compared to healthy patients, analyzing the increase of failure and loss of implants or bisphosphonate related osteonecrosis of the jaw (BRONJ) incidence. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in 'PICO' format was: In patients under bisphosphonate therapy, do dental implants placement, compared to healthy patients, increase the failure and loss of implants or bisphosphonate related osteonecrosis of the jaw incidence? PubMed/MEDLINE was searched for articles published up until April 15, 2015 using a combination of MeSH terms and their Entry terms. RESULTS: The search resulted in 375 articles. After selection according to the eligibility criteria, 15 studies fulfilled were included (eight retrospective, one prospective and six case series), with a total of 1339 patients analyzed, 3748 implants placed, 152 loss of implants and 78 cases of BRONJ. CONCLUSIONS: Due to the lack of randomized clinical trials looking at this theme, further studies with longer follow-up are needed to elucidate the remaining questions. Thus, it is wise to be careful when planning dental implant surgery in patients undergoing bisphosphonate therapy because of the risk of developing BRONJ as well as occurring failure of implant. Moreover, complete systemic condition of the patient must be also taking into considering when such procedures are performed

Influence of Connection Types and Implant Number on the Biomechanical Behavior of Mandibular Full-Arch Rehabilitation.

PURPOSE: To evaluate the influence of different implant numbers and connection types on the biomechanical behavior of mandibular full-arch implant-supported rehabilitation. MATERIALS AND METHODS: Computed tomography-based finite element models comprising a totally edentulous mandible and 3.8 × 13-mmdiameter implants, abutments, abutment screws, bar retaining screw, and bar were constructed. Different implant numbers (three, four, and five implants) and loading conditions (symmetrical/balanced, unilateral, and posterior with diverse loading magnitudes) were simulated for both external hex and Morse-taper connections. The peak equivalent strain (EQV strain) in the bone and the peak of von Mises stress (EQV stress) in the abutment screw and bar retaining screw were evaluated. RESULTS: Lower strain values were observed for a symmetrical loading distribution. Considering the same loading conditions, significantly higher bone strain levels were observed for external hex, compared with the Morse-taper connection. The number of implants had no significant influence on strain levels in bone, irrespective of the connection types. Compared with the external hex connection, the Morse-taper connection type presented significantly lower EQV stress values in abutment screws, but significantly higher stress in the bar retaining screw. Increasing the number of implants significantly reduced the EQV stress in the abutment screw and bar retaining screw. CONCLUSION: The Morse-taper connection type significantly decreased the strain levels in peri-implant bone, while increasing the stress in bar retaining screws. A smaller number of implants in an inferior full-arch rehabilitation slightly increased the stress in the abutment and bar retaining screws. Balanced adjustments of the loading improve the biomechanics of a mandibular full-arch rehabilitation.

Manipulação gengival para harmonia gengivo-dental em reabilitação unitária anterior com implante û relato de caso / Gingival management for gingival and dental harmony in anterior single rehabilitation with implant û case report

A harmonia gengivo-dental define estética nas reabilitações do arco superior. Em situações, nas quais ocorre perda óssea alveolar no sentido vestíbulo-lingual e ápico-coronal, é necessária associação de técnicas reconstrutivas, visando recuperar volume tecidual. Paciente do gênero masculino, 32 anos, perdeu elemento 11 devido à reabsorção radicular após trauma na região anterior. Foi feita extração dentária, seguida por enxerto ósseo em bloco, instalação de implante e restauração adesiva com dente de estoque. Após o período de osseointegração foi realizado enxerto conjuntivo subepitelial tanto para ganho no sentido vestíbulo-lingual, como ápico-coronal. Imediatamente após o enxerto, iniciou-se o condicionamento gengival com a própria prótese adesiva com pôntico em formato convexo. Em seguida, foi feita a reabertura do implante, instalação de intermediário e confecção de provisório, preservando a arquitetura gengival conseguida. O procedimento provou ser eficiente, garantindo margem gengival e volume de tecido muito próximos do dente adjacente e satisfazendo a expectativa estética do paciente.

The aesthetics of maxillary restorations is defined by the harmony between gingiva and teeth. gingival-dental harmony defines the aesthetics in the upper arch rehabilitation. In cases of alveolar bone loss in buccolingual and apical-coronal direction an association of techniques is required to recover the tissues volume. Male patient, 32 years old, lost element 11 due to radicular resorption, after trauma in the anterior region. Tooth extraction, block bone graft, implant installation and adhesive restoration with a stock tooth were performed. After osseointegration period, a subepithelial connective tissue graft was made to have gain in both directions, buccolingual and apical-coronal. Immediately after the graft, gingival conditioning started with the same adhesive prosthesis with convex shape pint. Then implant was reopened, abutment was installed and the preparation of provisional was executed, preserving the achieved gingival architecture. The procedure proved to be efficient, ensuring gingival margin and tissue volume very close to the adjacent tooth and satisfying the aesthetic expectations of the patient.

Correlation between the Mechanical Properties and Structural Characteristics of Different Fiber Posts Systems.

The aim of this study was to evaluate the flexural strength and flexural modulus of different fiber-reinforcement composite (FRC) posts and determine the correlation between mechanical properties and structural characteristics. Eleven brands of fiber posts were analyzed (n=10): Exacto Cônico (Angelus), DT Light SL (VDW), RelyX Fiber Post (3M-Espe), Glassix Radiopaque (Nordim), Para Post Fiber White (Coltène), FRC Postec Plus (Ivoclar), Aestheti-Plus Post (Bisco), Superpost Cônico Estriado (Superdont), Superpost Ultrafine (Superdont), Reforpost (Angelus), and White Post DC (FGM). The posts were loaded in three-point bending test to calculate the flexural strength and flexural modulus using a mechanical testing machine (EMIC 2000 DL) at 0.5 mm/min. Data were submitted to one-way ANOVA and Scott-Knot test (p<0.05). The cross-sections of the posts were examined by scanning electron microscopy (SEM). Correlation between the mechanical properties and each of the structural variables was calculated by Pearson's correlation coefficients (p<0.05). The flexural strength values ranged from 493 to 835 MPa and were directly correlated with the fiber/matrix ratio (p=0.011). The flexural modulus ranged from 4500 to 8824 MPa and was inversely correlated with the number of fibers per mm2 of post (p<0.001). It was concluded that the structural characteristics significantly affected the properties of the FRC posts. The structural characteristic and mechanical properties of fiber glass posts are manufacture-dependent. A linear correlation between flexural strength and fiber/matrix ratio, as well as the flexural modulus and the amount of fiber was found.

Correlation between the Mechanical Properties and Structural Characteristics of Different Fiber Posts Systems

Abstract The aim of this study was to evaluate the flexural strength and flexural modulus of different fiber-reinforcement composite (FRC) posts and determine the correlation between mechanical properties and structural characteristics. Eleven brands of fiber posts were analyzed (n=10): Exacto Cônico (Angelus), DT Light SL (VDW), RelyX Fiber Post (3M-Espe), Glassix Radiopaque (Nordim), Para Post Fiber White (Coltène), FRC Postec Plus (Ivoclar), Aestheti-Plus Post (Bisco), Superpost Cônico Estriado (Superdont), Superpost Ultrafine (Superdont), Reforpost (Angelus), and White Post DC (FGM). The posts were loaded in three-point bending test to calculate the flexural strength and flexural modulus using a mechanical testing machine (EMIC 2000 DL) at 0.5 mm/min. Data were submitted to one-way ANOVA and Scott-Knot test (p<0.05). The cross-sections of the posts were examined by scanning electron microscopy (SEM). Correlation between the mechanical properties and each of the structural variables was calculated by Pearson's correlation coefficients (p<0.05). The flexural strength values ranged from 493 to 835 MPa and were directly correlated with the fiber/matrix ratio (p=0.011). The flexural modulus ranged from 4500 to 8824 MPa and was inversely correlated with the number of fibers per mm2 of post (p<0.001). It was concluded that the structural characteristics significantly affected the properties of the FRC posts. The structural characteristic and mechanical properties of fiber glass posts are manufacture-dependent. A linear correlation between flexural strength and fiber/matrix ratio, as well as the flexural modulus and the amount of fiber was found.

Resumo O objetivo deste estudo foi avaliar a resistência à flexão e módulo de flexão de diferentes pinos reforçados com fibra (PRF) e determinar a correlação entre propriedades mecânicas e características estruturais. Foram analisadas onze marcas de pinos de fibra (n=10): Exacto Cónicos (Angelus), DT Luz SL (VDW), RelyX Fiber Post (3M ESPE), Glassix Radiopaque (Nordim), Pará Publicar Fiber White (Coltène), FRC Postec Plus (Ivoclar), Aestheti-Plus Post (Bisco), Superpost Cónicos Estriado (Superdont), Superpost Ultrafino (Superdont), Reforpost (Angelus), e White Post DC (FGM). Os pinos foram avaliados por meio de ensaio de flexão de três pontos para calcular a resistência à flexão e módulo de flexão utilizando uma máquina de ensaios mecânicos (EMIC 2000 DL) a 0,5 mm/min. Os dados foram submetidos a ANOVA one-way e teste de Scott-Knot (p<0,05). As secções transversais dos pinos foram examinadas usando microscopia eletrônica de varredura (MEV). A correlação entre as propriedades mecânicas e de cada uma das variáveis estruturais foi calculada por coeficientes de correlação de Pearson (p<0,05). Os valores da resistência à flexão variaram de 493-835 MPa e foram diretamente correlacionados com a proporção de fibra/matriz (p=0,011). O módulo de flexão variou de 4500 a 8824 MPa e foi inversamente correlacionado com o número de fibras por mm2 (p<0,001). Concluiu-se que as características estruturais afetam de forma significativa as propriedades dos pinos de fibra. As características estruturais e propriedades mecânicas dos pinos de fibra de vidro são dependentes do processo de fabricação. Existe uma correlação linear entre a resistência à flexão e proporção de fibra/matriz, bem como entre o módulo de flexão e a quantidade de fibras.