Electroencephalographic Response in Juvenile Tambaqui, Colossoma macropomum, Exposed to Short-Term Anaesthetic Baths with Geraniol and Citronellol.

The aim of this study was to evaluate the level of neuronal depression in juvenile tambaqui, Colossoma macropomum, exposed to geraniol (GRL) and citronellol (CTL) in immersion baths. A total of 36 juveniles weighing 35.2 ± 9.4 g were used, organised into six experimental groups: I-control (clean water); II-ethanol (water containing the highest volume of ethanol used in the anaesthetic pre-dilution); III-GRL induction (70 µL·L-1); IV-CTL induction (90 µL·L-1); V-GRL recovery; VI-CTL recovery. Electroencephalographic (EEG) recordings were performed for 300 s in each group. EEG tracings of the control and ethanol groups showed regular and similar activity. Upon exposure to the anaesthetics, irregularities were observed in the tracings showing neuronal excitability and increased amplitudes, mainly in the case of CTL. Overall, GRL-exposed fish showed depression of the central nervous system with low and regular tracings throughout induction, presenting a gradual recovery and stable tracings, which were consistent with an adequate general anaesthetic effect. On the other hand, fish exposed to CTL showed altered EEG activity during induction, that could be considered incompatible with an appropriate anaesthetic effect and smooth recovery, presenting high and irregular EEG tracing amplitudes.

Cardiac response in tambaqui Colossoma macropomum anaesthetised with Piper divaricatum essential oil.

The aim of this study was to evaluate the electrocardiographic responses of Colossoma macropomum exposed to short-term baths using the essential oil of Piper divaricatum (EOPD) as an anaesthetic-like agent in different doses (40, 60, and 80 µL L-1). Cardiac responses throughout and after exposure to EOPD were monitored and evaluated through mean heart rate (HR), duration and amplitude of the QRS complex (ventricular depolarization), and Q-T (ventricular contraction) and R-R (time between two successive QRS complexes) wave intervals. Across all doses, there was a marked depression of the HR, mainly at 80 µL L-1 EOPD. Mean amplitudes recorded for the QRS complex and Q-T interval at 40 µL L-1 EOPD were indistinguishable from the control, which could reinforce this concentration as sufficient and safe to promote fast anaesthesia without affecting cardiac function. Recovery from bradycardia, duration of the R-R interval, and QRS complex were similar at 60 and 80 µL L-1 EOPD; however, the Q-T interval at 80 µL L-1 EOPD revealed a more pronounced cardiac depression in relation to the controls and fish exposed to 60 µL L-1 EOPD. Thus, we conclude that 40 µL L-1 EOPD should suffice to induce fast, deep, and safe anaesthesia in tambaqui juveniles, whereas the concentration of 80 µL L-1 led to a greater depression of the cardiac function, albeit showing effect reversibility.

Eugenol induces body immobilization yet evoking an increased neuronal excitability in fish during short-term baths.

Several studies have suggested eugenol as a suitable anaesthetic for fish. However, it has also been regarded as a toxic and aversive substance to several aquatic organisms, including fish. This study sought to assess the eugenol-induced behavioural alterations and its seizurogenic potential to fish. Moreover, a distinctive methodology for an in vivo evaluation of the brain activity was also presented. Prior to the evaluation of eugenol-induced responses, fish were exposed to pentylenetetrazole (PTZ), to characterize any seizure-like patterns. Antagonizing responses to PTZ were assessed in fish receiving diazepam (BDZ) and subsequently exposed to PTZ. Tambaqui fish juveniles, Colossoma macropomum (15.8 ± 2.8 g) were used as models and assayed as follows: (i) fish exposed to PTZ (15 mM) and (ii) fish receiving a dose of BDZ (10 mg Kg-1) and later exposed to PTZ (15 mM) (BDZ-PTZ group). Thereafter, fish were evaluated throughout (iii) eugenol exposure at 65 µL L-1 (ethanolic solution) and recovery. Control fish and a vehicle control group (ethanol at 585 µL L-1) were also established. PTZ baths elicited body immobilization preceded by hyperactivity in a stereotyped seizure-like behaviour with increased EEG wave amplitude and frequency. PTZ effects in the brain were attenuated by a pre-administration of BDZ. Upon eugenol exposure, tambaqui had an intense neuronal excitability, showing a clonus-like seizure behaviour, also corroborated by the EEG patterns, which were consistent with a seizure-like response. Responses of eugenol-exposed fish resembled those of the PZT-exposed animals, with epileptiform discharges. EMG was in line with the EEG modulation, showing increased tracing oscillations and higher mean amplitudes in PTZ-exposed fish whereas in BDZ-PTZ group muscle contraction was less frequent and powerful. Fish exposed to eugenol showed initially some muscle activity followed by a loss of muscle tonus over time. In summary, our results showed that upon eugenol exposure, although a time-dependent body immobilization was attained, fish presented an intense neuronal excitability comparable to that evoked by PTZ. Eugenol failed to promote depression of the CNS and therefore may be not suitable to be used for general anaesthesia of C. macropomum. As eugenol could be implicated in seizurogenesis and be potentially toxic to the fish brain, protocols suggesting the broad use of eugenol for short-term anaesthesia or euthanasia of fish should be carefully revised, as it raises important concerns in terms of ethics and fish welfare.

Behavioural, electrocorticographic, and electromyographic alterations induced by Nerium oleander ethanolic extract: Anticonvulsant therapeutics assessment.

Nerium oleander Linn. is an Apocynaceae shrub which is among the most toxic ornamental plants. Although seizures are one of the symptoms associated with N. Oleander poisoning in humans, only a few studies are available on the behavioural and electrophysiological alterations caused by this plant poisoning. This study aimed at providing a thorough description of the electroencephalographic (EEG) and electromyographic (EMG) profiles throughout the experimental poisoning of Wistar rats (200-250 g) using ethanolic extract of N. oleander (EENO). Further, seizure control was assessed using different anticonvulsants. Male Wistar rat's behaviour was assessed upon EENO (150 mg/kg) administration and the animals were evaluated for muscle and neural activities through EMG and EEG recordings, respectively. The behavioural test showed two distinct phases of CNS activity: Phase I - myorelaxation and depression, and Phase II - excitability (agitated behaviour and seizures). Such phases were consistent with the EEG and EMG tracing patterns attained. Within the first 400 s of the recordings, during Phase I, the EMG showed no tracing amplitude variation. Later, the tracing pattern was changed and an intensification of the muscle contraction power in higher frequencies was observed during Phase II. The EEG showed initially a slight flattening in the tracings with a reduction in the intensity of the signal as per spectrogram of frequency attained. Thereafter, during Phase II, much higher amplitude tracings could be noted with an intensification of the signal, compatible with seizures. Seizure control was evaluated using four agents: phenytoin, phenobarbital, diazepam and scopolamine (at 10 mg/kg in all cases). While scopolamine was not effective in the seizure control, diazepam was the most efficient drug for the attenuation of the poisoning. Our results indicate the possibility of including phenytoin, phenobarbital and diazepam, mainly the latter, in the poisoning therapeutic protocol, including for those individuals who could be more susceptible to the poisoning by Nerium oleander as in the case of epileptic patients.

Cunaniol-elicited seizures: Behavior characterization and electroencephalographic analyses.

This study aimed at describing the characteristics and properties of seizures induced by cunaniol, a polyacetylenic alcohol isolated from the Clibadium genus, which is ubiquitous in the Amazon biodiversity and its potential use as a convulsant model. Wistar rat behavior was assessed upon cunaniol administration and animals were evaluated for neural activity through electroencephalographic records whereby epidural electrodes were positioned over the motor cortex under cunaniol-elicited seizures and seizure's control using three anticonvulsant agents, namely phenytoin, phenobarbital and diazepam. Cunaniol-induced seizures displayed a cyclic development of electrocorticographic seizures, presenting interictal-like spike and ictal period, which correlates to the behavioral observations and is in line with acute seizures induced by pentylenetetrazole. Cunaniol-elicited seizures were intractable by phenytoin treatment and controlled under the GABAergic activities of phenobarbital and diazepam. The results indicate that the cunaniol-induced changes show characteristics of seizure activity, making this plant compound a suitable animal convulsant model for seizure-related studies that could be used to assist in the development of novel anticonvulsant agents.

Clove oil induces anaesthesia and blunts muscle contraction power in three Amazon fish species.

Clove oil is used as an anaesthetic for many species of fish worldwide; however, relatively few studies have assessed its effectiveness on Amazon fish species and no compelling evidence has ever been reported on the relaxant properties of this oil for skeletal muscle of fish. Thus, the objective of this study was to evaluate the latencies to deep anaesthesia and recovery, along with the myorelaxant effect of clove oil on three Amazon fish species: cardinal tetra, Paracheirodon axelrodi, banded cichlid, Heros severus and angelfish, Pterophyllum scalare, submitted to short-term anaesthetic baths. Fish were assayed in three groups of 60 fish each and individually anaesthetized in a completely randomized design with six clove oil concentrations using 10 fish/species/concentration. Electromyographic recordings from dorsal muscle were performed during stages of induction and recovery in which nine fish/species/stage were used. Deep anaesthesia was attained for all concentrations tested, and no mortalities were observed throughout the experiments and after a 48-h observation period. Concentration of 90 µL L-1 and above promoted fast deep anaesthesia (< 3 min) and calm recovery in angelfish and cardinal tetra, whereas the concentration of 60 µL L-1 sufficed to quickly anaesthetize banded cichlid. Times to full recovery were not significantly contrasting among species and occurred within appropriate time threshold (< 5 min). Clove oil exerted a conspicuous depression of muscle contraction power, and therefore can be effectively used as a muscle relaxant agent for P. scalare, P. axelrodi, H. severus and potentially, for other fish species.

Osseointegrated implants placed at supracrestal level may harbour higher counts of A. gerencseriae and S. constellatus - a randomized, controlled pilot study.

PURPOSE: This study aimed at evaluating the bacterial colonization in dental implants inserted in the crestal or supracrestal position and correlated it to radiographic bone measurements. METHODS: Thirty-five implants with regular platform in nine patients (mean age 62.4±11.2 years) were inserted either at the bone crest level (control group) or at a suprecrestal level (test group). Radiographic examination was performed at baseline (implant installation) and after 6 months. Clinical and microbiological data were collected after 6 months. Digital radiography was used to assess bone remodeling (marginal bone loss and optical alveolar density). Bacterial profile was analyzed by checkerboard DNA-DNA hybridization, including a panel of 40 bacterial species. RESULTS: After 6 months, there were significantly higher counts of Actinomyces gerencseriae (p=0.009) and Streptococcus constellatus (p=0.05) in the test group. No significant differences between test and control groups were observed for marginal bone loss (p=0.725) and optical alveolar density (p=0.975). Probing depth was similar in both groups. CONCLUSION: Significantly higher counts of A. gerencseriae and S. constellatus were found in implants placed at the supracrestal level compared to the ones placed at the bone level. No relation was found between the installation level of dental implants and peri-implant bone remodeling.

Planning and treatment in oral rehabilitation with implant-supported prostheses using cephalometric analysis / Planejamento e tratamento em reabilitação oral com próteses sobre implantes usando análise cefalométrica

There are growing prosthetic and esthetic demands for Oral Rehabilitations on osseointegratable implants, requiring precise prosthetic-surgical planning. In edentulous patients planning may be done using cephalometric analysis to determine the position of the teeth in the dental prosthesis, and consequently, those of the implants. In this clinical case, the planning and treatment of an oral implant-supported rehabilitation is described, using cephalometry to optimize prosthetic success and patient comfort. The patient presented complete mandibular and partial maxillary edentulism, with unsatisfactory esthetics and function of the anterior teeth, with accentuated vestibular inclination. In order to determine the correct position of maxillary teeth it was necessary to use a Steiner cephalometric tracing to position the maxillary central incisor in the diagnostic wax-up. Therefore, the maxillary anterior teeth were extracted, osseointegratable implants were placed (Neodent(r), Curitiba, Brazil), and an immediate temporary fixed denture was inserted. After 30 days, surgery was performed for the placement of 4 osseointegratable implants (Neodent(r), Curitiba, Brazil) in the inter-mentonian region, on which a complete, temporary, implant-supported denture was placed. After the period of osseointegration, the definitive implant-supported dental prosthesis were fabricated.

Reabilitações orais sobre implantes osteointegráveis enfrentam crescentes exigências protéticas e estéticas, necessitando de um planejamento protético-cirúrgico preciso. O planejamento em pacientes edêntulos pode ser realizado usando análise cefalométrica para determinar o posicionamento dos dentes na prótese e conseqüentemente dos implantes. Esse caso clínico descreve o planejamento e tratamento de uma reabilitação oral sobre implantes usando análise cefalométrica para otimizar o sucesso protético assim como o conforto do paciente. Paciente apresentando edentulismo total mandibular e parcial maxilar com elementos anteriores insatisfatórios estética e funcionalmente, com inclinação vestibular acentuada. Para a determinação do correto posicionamento dos elementos superiores foi necessário a utilização de traçado cefalométrico de Steiner para o posicionamento do incisivo central superior no enceramento diagnóstico. Dessa forma, foi realizado exodontia dos elementos anteriores superiores, instalação de implantes osteointegraveis (Neodent(r), Curitiba, Brasil) e instalação de prótese fixa provisória imediata. Após 30 dias, foi realizada cirurgia para instalação de 4 implantes osteointegráveis (Neodent(r), Curitiba, Brasil) na região intermentoniana, sobre os quais foi instalada uma prótese total implanto-suportada inferior provisória. Após período de osteointegração, as próteses sobre implantes definitivas foram confeccionadas.

Torque removal evaluation of prosthetic screws after tightening and loosening cycles: an in vitro study.

OBJECTIVES: The aim of this study was to evaluate the variation in removal torque of implant prosthetic abutment screws after successive tightening and loosening cycles, in addition to evaluating the influence of the hexagon at the abutment base on screw removal torque. MATERIAL AND METHODS: Twenty hexagonal abutments were tightened to 20 regular external hex implants with a titanium alloy screw, with an insertion torque of 32 N cm, measured with a digital torque gauge. The implant/abutment/screw assemblies were divided into two groups: (1) abutments without hexagon at the base and (2) abutments with a hexagon at the base. Each assembly received a provisional restoration and was submitted to mechanical loading cycles. After this, the screws were removed and the removal torque was measured. This sequence was repeated 10 times, then the screw was replaced by a new one, and another cycle was performed. Linear regression analysis was performed. RESULTS: Removal torque values tended to decrease as the number of insertion/removal cycles increased, for both groups. Comparisons of the slopes and the intercepts between groups showed no statistical difference. There was no significant difference between the mean values of last five cycles and the 11th cycle. Within the limitations of this in vitro study, it was concluded that (1) repeated insertion/removal cycles promoted gradual reduction in removal torque of screws, (2) replacing the screw with a new one after 10 cycles did not increase resistance to loosening, and (3) removal of the hexagon from the abutment base had no effect on the removal torque of the screws.

Dimensional changes in gypsum fragments bonded with cyanoacrylate.

PURPOSE: Accidental fractures may occur during manipulation and transportation of plaster casts. In clinical practice, plaster fragments may be bonded without harming the accuracy of the final denture, provided that the bonding agent does not cause dimensional alterations. Cyanoacrylate could be a good material because of its ease of use, quick set, wide availability, and low cost. The aim of this study was to assess the dimensional alteration of Type IV plaster fragments bonded with a cyanoacrylate-based adhesive. MATERIALS AND METHODS: Ten hexagonal regular prisms were made of Type IV plaster, with two reference marks on one of the faces. The distance between the marks was measured under a comparison microscope. After this, the prisms were fractured so that the fracture line would be between the two reference marks, bonded with a cyanoacrylate-based universal adhesive and measured again. RESULTS: The mean difference between the measurements performed before and after fracture and bonding of the fragments was 0.0194 mm. At a level of significance of 0.05, there was no statistically significant difference between the measurements before and after fracture and bonding of the dies (p = 0.1582). CONCLUSION: It may be concluded that bonding of Type IV plaster fragments with a cyanoacrylate-based adhesive did not cause significant dimensional alterations.

Ictiofauna do estuário de São Caetano de Odivelas e Vigia (Pará, Estuário Amazônico) / Ichthyofauna of the estuary of São Caetano de Odivelas and Vigia (Pará, Amazon Estuary)

Fish diversity in the Amazon Basin is recognized as one of the highest in the world. However, information on the estuarine ichthyofauna of the region is still fragmented and based on localized inventories. This study reports on an inventory carried out in the estuaries of São Caetano de Odivelas and Vigia, State of Pará, a poorly known area within the Amazon Estuary. Two research cruises of four days long each were undertaken in 2003, one in June (austral winter) and other in December (summer), with use of gill nets, traps, cast net and hook-and-line. It was collected 1,689 individuals, including 58 species from 23 families, all of them previously recorded in the Amazon Estuary. Perciformes, Siluriformes and Clupeiformes were the most diverse taxa, comprising 73.8 percent of the species. From the 58 recorded species, 24 percent are pelagic, 50 percent are demersal and the remaining have pelagic-demersal habits. Coastal-marine species predominated in the region.

A diversidade de peixes da Bacia Amazônica é reconhecida como uma das mais altas do mundo. No entanto, o conhecimento acerca da ictiofauna do estuário do Rio Amazonas é fragmentado e baseado em levantamentos localizados. O presente trabalho apresenta um inventário da ictiofauna dos estuários de São Caetano de Odivelas e Vigia, Pará, numa área ainda pouco conhecida do estuário Amazônico. Foram efetuadas duas campanhas de coleta em 2003, com duração de quatro dias cada, uma em junho (inverno) e outra em dezembro (verão), com uso de diferentes artes de pesca (redes de emalhar, currais, tarrafas e linha). Foram coletados 1.689 indivíduos pertencentes a 58 espécies distribuídas em 23 famílias, todas com ocorrência anteriormente registrada no estuário amazônico. As ordens Perciformes, Siluriformes e Clupeiformes foram os grupos mais diversificados, abrangendo 73,8 por cento das espécies. Das 58 espécies registradas, 24 por cento são pelágicas, 50 por cento são demersais e as demais têm hábitos pelágico-demersais. Espécies de hábitos costeiro-marinho predominaram na região.

A rationale method for evaluating unscrewing torque values of prosthetic screws in dental implants.

OBJECTIVES: Previous studies that evaluated the torque needed for removing dental implant screws have not considered the manner of transfer of the occlusal loads in clinical settings. Instead, the torque used for removal was applied directly to the screw, and most of them omitted the possibility that the hexagon could limit the action of the occlusal load in the loosening of the screws. The present study proposes a method for evaluating the screw removal torque in an anti-rotational device independent way, creating an unscrewing load transfer to the entire assembly, not only to the screw. MATERIAL AND METHODS: Twenty hexagonal abutments without the hexagon in their bases were fixed with a screw to 20 dental implants. They were divided into two groups: Group 1 used titanium screws and Group 2 used titanium screws covered with a solid lubricant. A torque of 32 Ncm was applied to the screw and then a custom-made wrench was used for rotating the abutment counterclockwise, to loosen the screw. A digital torque meter recorded the torque required to loosen the abutment. RESULTS: There was a significant difference between the means of Group 1 (38.62 ± 6.43 Ncm) and Group 2 (48.47 ± 5.04 Ncm), with p=0.001. CONCLUSION: This methodology was effective in comparing unscrewing torque values of the implant-abutment junction even with a limited sample size. It confirmed a previously shown significant difference between two types of screws.

A rationale method for evaluating unscrewing torque values of prosthetic screws in dental implants

OBJECTIVES: Previous studies that evaluated the torque needed for removing dental implant screws have not considered the manner of transfer of the occlusal loads in clinical settings. Instead, the torque used for removal was applied directly to the screw, and most of them omitted the possibility that the hexagon could limit the action of the occlusal load in the loosening of the screws. The present study proposes a method for evaluating the screw removal torque in an anti-rotational device independent way, creating an unscrewing load transfer to the entire assembly, not only to the screw. MATERIAL AND METHODS: Twenty hexagonal abutments without the hexagon in their bases were fixed with a screw to 20 dental implants. They were divided into two groups: Group 1 used titanium screws and Group 2 used titanium screws covered with a solid lubricant. A torque of 32 Ncm was applied to the screw and then a custom-made wrench was used for rotating the abutment counterclockwise, to loosen the screw. A digital torque meter recorded the torque required to loosen the abutment. RESULTS: There was a significant difference between the means of Group 1 (38.62±6.43 Ncm) and Group 2 (48.47±5.04 Ncm), with p=0.001. CONCLUSION: This methodology was effective in comparing unscrewing torque values of the implant-abutment junction even with a limited sample size. It confirmed a previously shown significant difference between two types of screws.

The need for complete dentures in Brazil: an epidemiological approach for the next 10 years

The only two censuses on oral health (Levantamento Epidemiológico em Saúde Bucal em 1986 e Projeto em Saúde Bucal de 2003) show a tendency in the reduction of edentulous patients in Brazil. The aim of this article was to estimate the variation in rates of the need for dentures in Brazil in 2010 and 2020. The projection was obtained from a linear variation carried out between the 1986 and 2003 censuses. A formula was used to calculate the result, which showed a strong trend in the decline of the number of edentulous patients until 2020. After the result analyses, it was found that by 2020 the need for complete denture for people between 15 and 74 years old will be none. Unfortunately, the only two censuses on oral health do not give us sufficient data to show a reliable projection of edentulous patients in Brazil

Influence of application site of provisional cement on the marginal adaptation of provisional crowns.

INTRODUCTION: Marginal discrepancies may lead to cement washout and marginal leakage, damaging periodontal and pulp tissues or causing premature loss of the restoration. PURPOSE: This study evaluated the influence of application site of provisional cement on the marginal adaptation of provisional crowns. MATERIAL AND METHODS: Four different application sites of provisional cement (Temp Bond NE, Kerr Corporation) were used for cementation of provisional crowns on phantom teeth prepared for full crown restorations, performing 4 experimental groups (n=10): cement applied to all internal surfaces of the crown (CAO); cement applied to all internal surfaces of the crown, except for the occlusal surface (CA); cement applied to the cervical crown margin (CM); and cement applied to the cervical tooth margin (TM). A comparison microscope (Mitutoyo America Corporation) was used to measure the distances between the internal tangents of two circular marks, one made on the provisional crown and one made apical to the tooth preparation margin, in areas corresponding to buccal, lingual, mesial and distal surfaces. Marginal adaptation was determined before and after cementation, with 0.0001-mm accuracy. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. RESULTS: Mean values of marginal opening obtained for each group were: CAO: 145 microm; CA: 67 microm; CM: 46 microm; TM: 34 microm. CA, CM and TM presented significantly lower marginal openings than CAO (p<0.05). CONCLUSION: complete filling of the crown with provisional cement, including the occlusal surface, provided greater marginal discrepancies when compared to the other methods evaluated.

Influence of application site of provisional cement on the marginal adaptation of provisional crowns

Introduction: Marginal discrepancies may lead to cement washout and marginal leakage, damaging periodontal and pulp tissues or causing premature loss of the restoration. Purpose: This study evaluated the influence of application site of provisional cement on the marginal adaptation of provisional crowns. Material and Methods: Four different application sites of provisional cement (Temp Bond NE, Kerr Corporation) were used for cementation of provisional crowns on phantom teeth prepared for full crown restorations, performing 4 experimental groups (n=10): cement applied to all internal surfaces of the crown (CAO); cement applied to all internal surfaces of the crown, except for the occlusal surface (CA); cement applied to the cervical crown margin (CM); and cement applied to the cervical tooth margin (TM). A comparison microscope (Mitutoyo America Corporation) was used to measure the distances between the internal tangents of two circular marks, one made on the provisional crown and one made apical to the tooth preparation margin, in areas corresponding to buccal, lingual, mesial and distal surfaces. Marginal adaptation was determined before and after cementation, with 0.0001-mm accuracy. Data were analyzed statistically by ANOVA and Tukey’s test at 5% significance level. Results: Mean values of marginal opening obtained for each group were: CAO: 145 µm; CA: 67 µm; CM: 46 µm; TM: 34 µm. CA, CM and TM presented significantly lower marginal openings than CAO (p<0.05). Conclusion: complete filling of the crown with provisional cement, including the occlusal surface, provided grater marginal discrepancies when compared to the other methods evaluated.