Analyzing the safety of the parasiticide fungus Mucor circinelloides: first insights on its virulence profile and interactions with the avian gut microbial community.

Parasiticide fungi are considered an accurate, sustainable, and safe solution for the biocontrol of animal gastrointestinal (GI) parasites. This research provides an initial characterization of the virulence of the native parasiticide fungus Mucor circinelloides (FMV-FR1) and an assessment of its impact on birds' gut microbes. The genome of this fungus was sequenced to identify the genes coding for virulence factors. Also, this fungus was checked for the phenotypic expression of proteinase, lecithinase, DNase, gelatinase, hemolysin, and biofilm production. Finally, an in vivo trial was developed based on feeding M. circinelloides spores to laying hens and peacocks three times a week. Bird feces were collected for 3 months, with total genomic DNA being extracted and subjected to long-read 16S and 25S-28S sequencing. Genes coding for an iron permease (FTR1), iron receptors (FOB1 and FOB2), ADP-ribosylation factors (ARFs) (ARF2 and ARF6), and a GTPase (CDC42) were identified in this M. circinelloides genome. Also, this fungus was positive only for lecithinase activity. The field trial revealed a fecal microbiome dominated by Firmicutes and Proteobacteria in laying hens, and Firmicutes and Bacteroidetes in peacocks, whereas the fecal mycobiome of both bird species was mainly composed of Ascomycetes and Basidiomycetes fungi. Bacterial and fungal alpha-diversities did not differ between sampling time points after M. circinelloides administrations (P = 0.62 and P = 0.15, respectively). Although findings from this research suggest the lack of virulence of this M. circinelloides parasiticide isolate, more complementary in vitro and in vivo research is needed to conclude about the safety of its administration to birds, aiming at controlling their GI parasites.IMPORTANCEA previous study revealed that the native Mucor circinelloides isolate (FMV-FR1) can develop parasiticide activity toward coccidia oocysts, one of the most pathogenic GI parasites in birds. However, ensuring its safety for birds is of utmost importance, namely by studying its virulence profile and potential effect on commensal gut microbes. This initial study revealed that although this M. circinelloides isolate had genes coding for four types of virulence factors-iron permease, iron receptors, ADP-ribosylation factors, and GTPase-and only expressed phenotypically the enzyme lecithinase, the administration of its spores to laying hens and peacocks did not interfere with the abundances and diversities of their gut commensal bacteria and fungi. Although overall results suggest the lack of virulence of this M. circinelloides isolate, more complementary research is needed to conclude about the safety of its administration to birds in the scope of parasite biocontrol programs.

Arachnid Fauna (Araneae and Opiliones) from the Castro Verde Special Protection Area, southern Portugal.

Background: With the increasing recognition of the significance of arachnid conservation, it is crucial to allocate greater efforts towards implementing targeted monitoring programmes. Despite recent studies, our understanding of arachnid populations in Portugal remains limited. This study serves as the initial inventory of arachnids (Araneae and Opiliones) within the Castro Verde Special Protection Area (SPA) located in Beja, southern Portugal. The surveys were conducted during the spring of 2012 across 80 open grasslands that were grazed by cattle and sheep. New information: A total of 71 species of Araneae and two species of Opiliones have been identified. Notably, three spider species, namely Argennasubnigra, Civizelotesibericus and Walckenaeriacucullata, are documented for the first time in Portugal. Additionally, two harvestmen species (Dasylobusibericus and Homalenotusbuchneri) and 14 spider species (Cheiracanthiumpennatum, Haplodrassusrhodanicus, Marinarozelotesminutus, Tapinocybaalgirica, Agraecinalineata, Tibellusmacellus, Talaverapetrensis, Tetragnathaintermedia, Dipoenaumbratilis, Enoplognathadiversa, Neottiurauncinata, Ruborridionmusivum, Theridionpinastri and Xysticusgrallator) are recorded for the first time in the Beja District. The occurrence of each documented species within the SPA, including family and species details, is presented, underscoring the significance of the Castro Verde SPA for arachnid conservation. These findings contribute novel insights into the biodiversity of the Castro Verde SPA, emphasising the necessity of incorporating this area into arachnid diversity conservation efforts.

The genome sequence of the cave orb-weaver, Meta bourneti (Simon, 1922).

We present a genome assembly from an individual male Meta bourneti (the cave orb-weaver; Arthropoda; Arachnida; Araneae; Tetragnathidae). The genome sequence is 1,383 megabases in span. Most of the assembly is scaffolded into 13 chromosomal pseudomolecules, including half coverage of two X sex chromosomes. The mitochondrial genome has also been assembled and is 15.8 kilobases long.

Algoneurodystrophy in a Patient with Major Depressive Disorder.

Introduction. Not infrequently, in patients with a psychiatric illness who have concomitant physical symptoms, these symptoms are often wrongly attributed to a psychiatric illness. Consequently, there is a delay in establishing the correct diagnosis, which may have an impact on the prognosis of the disease. The authors aim to present a case report of a patient with a diagnosis of major depressive disorder and conversion disorder that was later correctly diagnosed with algoneurodystrophy. The authors intend to draw attention to the importance of a careful medical history and this entity. Case Presentation. A patient went to the emergency department multiple times with complaints of decreased strength and pain in the right upper limb, concomitantly with depressive symptoms. The patient was first diagnosed with conversion disorder and major depressive disorder. After the worsening of the clinical condition with the appearance of neuropathic pain and the exclusion of other organic pathologies, the probable diagnosis of algoneurodystrophy was made. At that time, the patient started treatment and a favorable clinical evolution was observed. Discussion. The clinical case highlights the importance of conducting a careful medical history in a patient with a psychiatric illness, so as not to mistakenly exclude the presence of an organic disease. The absence or delay in making a correct diagnosis can have adverse consequences in terms of the prognosis of the disease.

Species conservation profiles of tarantula spiders (Araneae, Theraphosidae) listed on CITES.

BACKGROUND: CITES is an international agreement between governments to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Regarding spiders, all species listed in CITES are tarantulas. They are included in Appendix II, meaning that they are species that are not necessarily now threatened with extinction but that they may become so unless trade is closely controlled.Many tarantulas are legally and illegally traded in the pet market and they are one of the most traded invertebrate groups. Originally, the CITES list published in 1995 included all the current species of the genus Brachypelma Simon, 1891 plus Aphonopelma pallidum (F. O. Pickard-Cambridge, 1897) and the so-called Aphonopelma albiceps (Pocock, 1903). After that, some taxonomic changes were done, as well as descriptions of new species in the genus Brachypelma. The objective of this paper is to assess the 21 taxonomically valid spider species listed on CITES according to the IUCN criteria, study the general patterns and trends and advise on possible future conservation actions critical for the survival of endangered species. NEW INFORMATION: Amongst all 21 species assessed, 16 had sufficient data on their distribution, ecology and threats to properly understand their current status and suggest possible conservation measures. A decline in the area of occupancy (AOO) and extent of occurrence (EOO) was inferred to almost all species, caused mostly by human activities (urbanisation, roads, agricultural and touristic activities), which often lead to the complete loss of subpopulations across their range. Hurricanes and frequent rising water, which are increasing in frequency due to climate change, can cause decline in habitat quality and consequent change in EOO and AOO of some species and should also be considered when planning conservation actions. Severe fragmentation was detected in 13 species and is therefore one of the most relevant threats to the most endangered Brachypelma species and should be made a priority aspect to deal with when proposing conservation actions for the group. Regarding the loss of individuals in wild populations, the main cause seems to be the overharvesting to meet the illegal trade.The most important conservation actions identified across species include preserving their natural habitat through protected areas, establishing management plans for both the species and their habitats and undertaking systematic monitoring to provide information about population recovery and species re-introduction programmes. In general, we propose to prioritise and support research on the population trends and distribution, as well as on the impact of land use and habitat degradation. Special attention regarding conservation actions and research plans has to be given to the central Pacific coastal area of Mexico, particularly around Guerrero State where five species of Brachypelma occur. Critically, for some of the most endangered species, such as B. baumgarteni and B. hamorii, there is no official protected area in their range of occurrence. It would therefore be highly recommended to establish at least one conservation unit which focuses on protecting each of these species in situ. In some cases, basic taxonomic research is needed before development of any appropriate conservation action can be proposed.

Species conservation profiles of spiders (Araneae) endemic to mainland Portugal.

BACKGROUND: The Iberian Peninsula is a diverse region that contains several different bioclimatic areas within one confined space, leading to high biodiversity. Portugal distinguishes itself in this regard by having a high count of spider species (829) and a remarkable number of endemic spider species (42) for its size (approximately 88,890 km2). However, only one non-endemic species (Macrothele calpeiana) is currently protected by the Natura 2000 network and no endemic spider species (aside from Anapistula ataecina) has been assessed according to the IUCN Red List criteria. The objective of this paper is to assess all non-assessed endemic species (41) as well as M. calpeiana. NEW INFORMATION: The 43 assessed species belong to 15 families, the richest being Zodariidae, Dysderidae, Linyphiidae and Gnaphosidae. In general and despite the lack of information on more than half the species, general patterns and trends could be found.Only 18 species (including M. calpeiana and A. ataecina) had enough data to allow their EOO (extent of occurrence) and AOO (area of occurrence) to be quantified. Of these, we modelled the distribution of 14 epigean species, eight of which were found to be widespread. The remaining six fulfilled at least one of the criteria for threatened species. Four species are troglobiont, all of which meet the EOO and AOO thresholds for threatened species. The remaining 25 Portuguese endemics had no reliable information on their range. Only nine species out of the 43 are estimated to be in decline and 11 are stable, with the majority of species having no information on trends (23 species).Forest areas, sand dunes, shrublands and caves host the majority of species. As such, the threats to Portuguese endemics reflect the diversity of habitats they occupy. Urbanisation and climate change seem to be the most important threats to these species, although other factors are also important and represented across the data.A considerable proportion of the currently known Portuguese endemic species can be found in national protected areas, with higher prominence to the Serras de Aire e Candeeiros, Douro Internacional, Vale do Guadiana, Sudoeste Alentejano e Costa Vicentina and Arrábida Natural Parks. These correspond mostly to areas that have been particularly well sampled during the last two decades.

Globally distributed occurrences utilised in 200 spider species conservation profiles (Arachnida, Araneae).

BACKGROUND: Data on 200 species of spiders were collected to assess the global threat status of the group worldwide. To supplement existing digital occurrence records from GBIF, a dataset of new occurrence records was compiled for all species using published literature or online sources, from which geographic coordinates were extracted or interpreted from locality description data. NEW INFORMATION: A total of 5,104 occurrence records were obtained, of which 2,378 were from literature or online sources other than GBIF. Of these, 2,308 had coordinate data. Reporting years ranged from 1834 to 2017. Most records were from North America and Europe, with Brazil, China, India and Australia also well represented.

Species conservation profiles of a random sample of world spiders IV: Scytodidae to Zoropsidae.

BACKGROUND: The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). The current contribution is the final in four papers that will constitute the baseline of a future spider SRLI encompassing 200 species distributed across the world. NEW INFORMATION: A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognised species names for the group. The selected species were classified taxonomically at the family level and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 50 species belonging to the families alphabetically arranged between Scytodidae and Zoropsidae, which encompassed Scytodidae, Selenopidae, Sicariidae, Sparassidae, Tetrablemmidae, Tetragnathidae, Theraphosidae, Theridiidae, Theridiosomatidae, Thomisidae, Trochanteriidae, Zodariidae and Zoropsidae.

Species conservation profiles of a random sample of world spiders III: Oecobiidae to Salticidae.

BACKGROUND: The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). The current contribution is the third in four papers that will constitute the baseline of a future spider SRLI encompassing 200 species distributed across the world. NEW INFORMATION: A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognized species names for the group. The 200 selected species where divided taxonomically at the family level, and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 58 species belonging to the famillies alphabetically arranged between Oecobiidae and Salticidae, which encompassed Oecobiidae, Oonopidae, Orsolobidae, Oxyopidae, Palpimanidae, Philodromidae, Pholcidae, Pisauridae, Prodidomidae and Salticidae.

Species conservation profiles of a random sample of world spiders II: Gnaphosidae to Nemesiidae.

BACKGROUND: The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). The current contribution is the second in four papers that will constitute the baseline of a future spider SRLI encompassing 200 species distributed across the world. NEW INFORMATION: A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognised species names for the group. The 200 selected species where divided taxonomically at the family level and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 45 species belonging to the families alphabetically arranged between Gnaphosidae and Nemesiidae, which encompassed Gnaphosidae, Idiopidae, Linyphiidae, Liocranidae, Lycosidae, Micropholcommatidae, Mysmenidae and Nemesiidae.

Species conservation profiles of a random sample of world spiders I: Agelenidae to Filistatidae.

BACKGROUND: The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). With the current contribution and the three following papers, we intend to create the first point in time of a future spider SRLI encompassing 200 species distributed across the world. NEW INFORMATION: A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognised species names for the group. The 200 selected species where divided taxonomically at the family level and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 46 species belonging to the famillies alphabetically arranged between Agelenidae and Filistatidae, which encompassed Agelenidae, Amaurobiidae, Anyphaenidae, Araneidae, Archaeidae, Barychelidae, Clubionidae, Corinnidae, Ctenidae, Ctenizidae, Cyatholipidae, Dictynidae, Dysderidae, Eresidae and Filistatidae.

O desempenho da zircônia como biomaterial de uso odontológico / Performance of zirconia as a biomaterial for dental use

As cerâmicas de zircônia apresentam ótimas propriedades como biocompatibilidade, resistência flexural e dureza, tornando-se uma possível alternativa para substituição das restaurações metalocerâmicas. Entretanto, a zircônia sofre degradação superficial quando exposta ao calor e à umidade, e a utilização de estabilizadores e o domínio do processamento são relatados para melhorar a sua resistência. O uso da zircônia na Odontologia é uma realidade, mas pesquisas ainda são necessárias para avaliar seu desempenho a longo prazo na cavidade oral. Dessa forma, o objetivo deste estudo foi, através de uma revisão bibliográfica, avaliar o desempenho da zircônia como um biomaterial de uso odontológico...

Zirconia ceramics have excellent properties, such as biocompatibility, flexural strength and, hardness, and therefore are viable alternatives to metal-ceramic restorations. However, zirconia suffers superficial degradation when exposed to heat and humidity, thus the use of stabilizers and proper process of the area are important in order to improve its resistance. The use of zirconia in Dentistry is a reality, but studies are needed to assess its performance in long periods in the oral cavity. Thus, the objective of this study was to evaluate the performance of zirconia as a biomaterial for dental use through a literature review...

Sphodromantisviridis (Forskal, 1775): New for Portugal and new records of the rare and small mantids Apteromantisaptera (Fuente, 1894) and Perlamantisallibertii Guérin-Méneville, 1843 in the country (Mantodea: Mantidae and Amorphoscelidae).

Several new records are presented on some of the least known mantis species in the Iberian Peninsula. From data collected in Portugal, their analysis has proven to represent an important advancement in the knowledge of this group of insects for the country and the Western Mediterranean area. Twenty new citations provide a better understanding on the distribution of the crepuscular species Perlamantisallibertii, the IUCN red listed Apteromantisaptera and the first Portuguese records of Sphodromantisviridis, extending their western limits of occurrence in Europe. The data thus gathered emphasizes the need to invest in biodiversity assessment for increased knowledge on species distribution and phenology but also for monitoring over time, essential to better ascertaining ecosystem services, the effects of climate change and habitat conservation.

Prótese parcial removível com attachment para reabilitação oral: relato de caso / Removable dental prosthesis with attachment for oral rehabilitation: a clinical report

Abordar os principais aspectos relacionados à reabilitação oral ao relatar um caso clínico utilizando prótese parcial removível (PPR) com attachment ball. Discussão: As próteses implanto-suportadas são consideradas um tratamento efetivo para a reabilitação de muitos pacientes desdentados parciais. No en¬tanto, limitações ósseas e/ou sistêmicas e o custo elevado dos implantes podem contraindicar essa modalidade terapêutica. Assim, a reabilitação oral com PPR torna-se uma ótima opção de tratamento. É conhecido que as PPRs a grampo não apresentam boa estética em muitas situações clínicas; porém, PPRs associadas a attachments permitem diversas possibilidades de soluções clínicas quando um diagnóstico e plano de tratamento mais elaborado podem ser executados. Conclusão: A PPR retida por attachment propicia resultado estético superior, transmissão adequada da carga mastigatória aos dentes suportes e excelente retenção...

To discuss the main aspects related to oral rehabilitation through the report of a clinical case using removable dental prosthesis (RDP) with ball attachment. Discussion: The implant-supported fixed restorations are considered an effective treatment for the rehabilitation of many partially edentulous patients. However, bone and/or systemic limitations and the high cost of implants may contraindicate this therapeutic modality. Thus, the oral rehabilitation using RDP becomes a great treatment option. It is known that RDP retained to a clip do not present a good esthetic in several clinical conditions; however, the RDP with attachments allows several possibilities for clinical solutions when a diagnosis and a more elaborated treatment plan can be performed. Conclusion: The RDP with attachment provides better aesthetical result, adequate transmission of masticatory load to support teeth and an excellent retention...

Uma revisão do conceito all-on-four / All-on-four concept: a literature review

Grandes avanços na história da Implantodontia vêm sendo documentados, porém, existem ainda algumas limitações no tratamento reabilitador com implantes dentários, o que desafia os profissionais a buscarem novas opções de tratamento. Pacientes que apresentam atrofia maxilar necessitam de procedimentos mais complexos, como enxertos ósseos extensos. Uma proposta de tratamento mais simplificada, com menor morbidade e menor tempo de tratamento, foi desenvolvida (Sistema all-on-four). Essa proposta de tratamento se baseia na redução do número de implantes compensada por um maior espaçamento entre eles, além da utilização dos implantes distais inclinados unidos por uma estrutura rígida que favorece a biomecânica e diminui a extensão do cantiléver.

Important progresses in the history of implants have been documented, but there are still some limitations in treatment rehabilitation with dental implants, challenging professionals to search for new treatment alternatives. Patients, with maxillary atrophy demand more complex procedures such as extensive bone grafts. A basic proposal for a treatment with lower morbidity and short-term duration has been developed (The All-on-Four Concept). This is based on reducing the number of implants compensated by an enlarged space between them, besides the use of tilted distal implants connected through a rigid structure that favors biomechanics and reduces cantilever extension.

Loss of interest, depressed mood and impact on the quality of life: cross-sectional survey.

BACKGROUND: Depressive symptoms and chronic disease have adverse effects on patients' health-related quality of life (H-RQOL). However, little is known about this effect on H-RQOL when only the two core depressive symptoms - loss of interest and depressed mood - are considered. The objective of this study is to investigate H-RQOL in the presence of loss of interest and depressed mood at a general medical outpatient unit. METHODS: We evaluated 553 patients at their first attendance at a general medical outpatient unit of a teaching hospital. H-RQOL was assessed with the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). Depressed mood and loss of interest were assessed by the Primary Care Evaluation of Mental Disorders (PRIME-MD)-Patient Questionnaire. A physician performed the diagnosis of chronic diseases by clinical judgment and classified them in 13 possible pre-defined categories. We used multiple linear regression to investigate associations between each domain of H-RQOL and our two core depression symptoms. The presence of chronic diseases and demographic variables were included in the models as covariates. RESULTS: Among the 553 patients, 70.5% were women with a mean age of 41.0 years (range 18-85, SD ± 15.4). Loss of interest was reported by 54.6%, and depressed mood by 59.7% of the patients. At least one chronic disease was diagnosed in 59.5% of patients; cardiovascular disease was the most prevalent, affecting 20.6% of our patients. Loss of interest and depressed mood was significantly associated with decreased scores in all domains of H-RQOL after adjustment for possible confounders. The presence of any chronic disease was associated with a decrease in the domain of vitality. The analysis of each individual chronic disease category revealed that no category was associated with a decrease in more than one domain of H-RQOL. CONCLUSION: Loss of interest and depressed mood were associated with significant decreases in H-RQOL. We recommend these simple tests for screening in general practice.

Arachnids secrete a fluid over their adhesive pads.

BACKGROUND: Many arachnids possess adhesive pads on their feet that help them climb smooth surfaces and capture prey. Spider and gecko adhesives have converged on a branched, hairy structure, which theoretically allows them to adhere solely by dry (solid-solid) intermolecular interactions. Indeed, the consensus in the literature is that spiders and their smooth-padded relatives, the solifugids, adhere without the aid of a secretion. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the adhesive contact zone of living spiders, solifugids and mites using interference reflection microscopy, which allows the detection of thin liquid films. Like insects, all the arachnids we studied left behind hydrophobic fluid footprints on glass (mean refractive index: 1.48-1.50; contact angle: 3.7-11.2°). Fluid was not always secreted continuously, suggesting that pads can function in both wet and dry modes. We measured the attachment forces of single adhesive setae from tarantulas (Grammostola rosea) by attaching them to a bending beam with a known spring constant and filming the resulting deflection. Individual spider setae showed a lower static friction at rest (26%±2.8 SE of the peak friction) than single gecko setae (Thecadactylus rapicauda; 96%±1.7 SE). This may be explained by the fact that spider setae continued to release fluid after isolation from the animal, lubricating the contact zone. SIGNIFICANCE: This finding implies that tarsal secretions occur within all major groups of terrestrial arthropods with adhesive pads. The presence of liquid in an adhesive contact zone has important consequences for attachment performance, improving adhesion to rough surfaces and introducing rate-dependent effects. Our results leave geckos and anoles as the only known representatives of truly dry adhesive pads in nature. Engineers seeking biological inspiration for synthetic adhesives should consider whether model species with fluid secretions are appropriate to their design goals.

Revisão dos princípios fundamentais de prótese sobreimplante parafusada e cimentada / Review of fundamental principles for screwed- and cement-retained implant-supported prostheses

Os implantes osseointegráveis representam grande avanço no tratamento odontológico, proporcionando significativa melhora no restabelecimento da saúde bucal, da função e da estética. Com seu advento, novos conceitos foram incrementados às técnicas de reabilitação oral. Ao revisar esses conceitos, o presente trabalho busca avaliar as vantagens, desvantagens, indicações e contraindicações de cada modalidade de retenção sobreimplantes. A pesquisa da literatura pertinente ao tema avaliou estudos clínicos, experimentais, revisões da literatura e livros entre os anos de 1981 a 2010. Muitas vezes, a escolha do tipo de retenção baseia-se somente na preferência do profissional, porém, a seleção do sistema de retenção deve ter uma indicação precisa para cada caso. Para tanto, o protesista deve ter conhecimento sobre os princípios fundamentais de passividade e adaptação da restauração protética, estética, espaço interoclusal, saúde dos tecidos moles peri-implantares, necessidade de manutenção, reversibilidade da restauração e aspectos oclusais de cada uma das opções protéticas para adequada execução dos casos clínicos. Conclui-se que a escolha do sistema de retenção não deve ser feita de forma genérica e sim ser individualizada dentro da particularidade de cada caso. Não devemos pensar que uma retenção seja melhor ou pior quando comparamos próteses retidas por cimento versus parafuso, o que deve ser levado em consideração são vantagens, desvantagens, indicações e contraindicações de cada caso em particular.

The osseointegrated implants represent a major advance in dental treatment, providing a significant improvement in the restoration of oral health, function, and aesthetics. Since its advent, new concepts evolved in techniques for oral rehabilitation. When reviewing these concepts, this study sought to determine the advantages, disadvantages, indications, and contraindications for each type of retention. The literature research evaluated clinical studies, research, literature reviews, and books between the years of 1981 to 2010. Oftentimes, the choice of retention is based solely on the preference of professional, but selection of the system should have an indication for each case. Thus, dental clinicians must know the fundamental principles of passivity and fit of prosthetic restorations; interocclusal space; aesthetic; peri-implant soft tissue health; need for maintenance; retrievability, and occlusal aspects of each prosthetic option for proper implementation in clinical cases. We conclude that the choice of retention system should never be made by chance, but individualized within the particularity of each case. Screwed- are not superior to cement-retained prostheses and vice-versa; thus one must take into account the advantages, disadvantages, indications, and contraindications of each particular case.