Exposure to the herbicide Tebuthiuron affects behavior, enzymatic activity, morphology and physiology of the midgut of the stingless bee Partamona helleri.

Partamona helleri is an important pollinator in the Neotropics. However, this bee faces an increased risk of pesticide exposure, potentially affecting both individual bees and entire colonies. Thus, this study aimed to evaluate the effects of the herbicide tebuthiuron on behavior, antioxidant activity, midgut morphology, and signaling pathways related to cell death, cell proliferation and differentiation in P. helleri workers. tebuthiuron significantly reduced locomotor activity and induced morphological changes in the midgut. The activity of the detoxification enzymes superoxide dismutase and glutathione S-transferase increased after exposure, indicating a detoxification mechanism. Furthermore, the herbicide led to alterations in the number of positive cells for signaling-pathway proteins in the midgut of bees, suggesting induction of apoptotic cell death and disruption of midgut epithelial regeneration. Therefore, tebuthiuron may negatively impact the behavior, antioxidant activity, morphology, and physiology of P. helleri workers, potentially posing a threat to the survival of this non-target organism.

Effect of artificial eccentric occlusal interferences on masticatory performance: A randomised double-blind clinical trial.

BACKGROUND: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. OBJECTIVE: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. METHODS: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests. RESULTS: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944). CONCLUSION: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. CLINICAL TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (RBR-8g5zfg8).

COVID-19 hospitalized patients and oral changes: a case-control study.

OBJECTIVES: To investigate the association between hospitalization for COVID-19 and oral changes, and to evaluate whether oral changes can indicate a higher risk of disease progression to death. MATERIALS AND METHODS: This case-control study analyzed patients hospitalized (university hospital), including those in intensive care unit and clinical wards. The study group comprised 69 COVID-19 positive patients (PCR-test), while the control group included 43 COVID-19 negative patients. A dentist performed oral evaluations, and salivary samples were collected for calcium, phosphatase, and pH analysis. Sociodemographic data, hospitalization information, and hematological test results were collected from electronic-medical records. The presence of oral changes was assessed using chi-square tests, and the predicted risk of death was analyzed using binary logistic regression. RESULTS: COVID-19 positive patients had a significantly higher prevalence of oral changes compared to COVID-19 negative patients. The presence of any oral changes in COVID-19 positive patients indicated a 13-fold higher risk of mortality. "Bleeding ulcers," "pressure ulcers," and "angular cheilitis" were significantly associated with hospitalization for COVID-19. CONCLUSION: There may be an association between hospitalization for COVID-19 and the development of oral changes, including bleeding ulcers, pressure ulcers. and angular cheilitis. These oral changes may serve as potential indicator for disease progression an increased risk of death. CLINICAL RELEVANCE: COVID-19 hospitalized patients have a higher prevalence of oral changes, which indicate an increased risk of mortality. Oral medicine staff should be included in multidisciplinary teams to detect and treat these oral changes promptly.

Toxicological assessment of agrochemicals on bees using machine learning tools.

Machine learning (ML) is a branch of artificial intelligence (AI) that enables the analysis of complex multivariate data. ML has significant potential in risk assessments of non-target insects for modeling the multiple factors affecting insect health, including the adverse effects of agrochemicals. Here, the potential of ML for risk assessments of glyphosate (herbicide; formulation) and imidacloprid (insecticide, neonicotinoid; formulation) on the stingless bee Melipona quadrifasciata was explored. The collective behavior of forager bees was analyzed after in vitro exposure to agrochemicals. ML algorithms were applied to identify the agrochemicals that the bees have been exposed to based on multivariate behavioral features. Changes in the in situ detection of different proteins in the midgut were also studied. Imidacloprid exposure leads to the greatest changes in behavior. The ML algorithms achieved a higher accuracy (up to 91%) in identifying agrochemical contamination. The two agrochemicals altered the detection of cells positive for different proteins, which can be detrimental to midgut physiology. This study provides a holistic assessment of the sublethal effects of glyphosate and imidacloprid on a key pollinator. The procedures used here can be applied in future studies to monitor and predict multiple environmental factors affecting insect health in the field.

Effects of sub-lethal doses of nisin on the virulence of Salmonella enterica in Galleria mellonella larvae.

Salmonella enterica is a pathogen that induces self-limiting gastroenteritis and is of worldwide concern. Nisin, an antimicrobial peptide, has emerged as an alternative for the control of microbial growth but its effect on the virulence of pathogenic bacteria is not yet well-explored. This work aimed to evaluate the virulence of S. enterica in the presence of sub-inhibitory nisin using the experimental model Galleria mellonella. Sub-inhibitory concentrations of nisin of 11.72 and 46.88 µM did not affect the cellular viability of S. enterica but promoted changes in gene expression within 1 h of treatment, with increases of up to 3-fold of pagC, 1.8-fold of invA and 2.3-fold of invF. Larvae of G. mellonella inoculated with S. enterica combined with nisin at 46.88 µM presented mortality, and TL50 noticeably increased to 50% and 80% at 24 and 48 h post-infection, respectively. Defence responses, such as melanisation, nodulation, pseudopodia, immune response, and expression of defence proteins of the larvae G. mellonella were enhanced when the treatments with S. enterica were combined with 11.72 or 46.88 µM nisin. These results show an increase in virulence of S. enterica by sub-MIC concentration of nisin that needs to be explored.

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress.

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Impact of mother-infant interaction on development during the first year of life: A systematic review.

The objectives of this project were to systematically review the impact of mother-infant interaction on the development of infants 12 months or younger and determine factors that mediate this relationship and early development. We systematically reviewed the literature and identified 21 papers which fulfilled inclusion and exclusion criteria. The majority of the studies found significant association between mother-infant interaction and language, cognition, motor, and social development during the first year of life. Only seven studies assessed motor development and four studies found significant relationship between motor development and mother-infant interaction. Prematurity, infant age, multiples births, maternal anxiety, maternal opioid exposure, history of foster care, and criminal record were the only factors found to mediate the relationship between mother-infant interaction and social, cognitive, and language development. The quality of the interactions between a mother and infant can both positively and negatively influence cognitive, language, and social outcomes during the first year of life. Additional research is needed to determine the influence of mother-infant interaction on motor development. Future research is needed on the efficacy of interventions designed to alter mother-infant interaction with the ultimate goal of achieving positive developmental outcomes during the first year of life.

Biological and molecular characterization of a bacteriophage infecting Xanthomonas campestris pv. campestris, isolated from brassica fields.

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot of crucifers. Here, we report a virus that infects Xcc isolated from brassica fields in Brazil. Morphological, molecular and phylogenetic analysis indicated that the isolated virus is a new member of the genus Pbunavirus, family Myoviridae, and we propose the name "Xanthomonas virus XC 2" for this virus. The isolated virus has a narrow host range, infecting only Xcc isolates, and it did not infect unrelated bacteria. These results indicate that the isolated bacteriophage is highly specific for Xcc and may be a potential agent for biological control.

Effects of virtual reality in body oscillation and motor performance of children with cerebral palsy: A preliminary randomized controlled clinical trial.

BACKGROUND AND PURPOSE: Virtual reality is an adjuvant technique to rehabilitation of children with cerebral palsy (CP). It has been gaining prominence in this field because of its accessibility and great levels of motivation it promotes in treatment. However, there is a lack of studies addressing the effects of virtual reality-based therapy on activity levels regarding postural stability, especially considering the level of evidence presented by studies addressing this issue. Therefore, we aim to evaluate the effects of intervention in body sway and gross motor function of children with CP using an active video game. MATERIALS AND METHODS: In this blind randomized controlled trial, fifteen children with CP, Gross Motor Function Classification System (GMFCS) I-II, regularly attending conventional physical therapy programs, were randomly assigned to an intervention (IG:n = 7) or to a control group (CG:n = 8). In both groups, children remained attending conventional therapy. In addition, IG underwent intervention using an active video game twice a week for 45 min and eight weeks. Standing body sway was assessed using a force plate, and Gross Motor Function Measure (GMFM) dimensions D (Standing) and E (Walking, Running and Jumping) were tested. RESULTS: Following the virtual reality-based intervention, the IG only showed significant improvements in the GMFM dimensions D (p = 0.021) and E (p = 0.008). Improvements were clinically significant (D = 10.8%; E = 14.0%). For the CG, no variable analyzed showed differences after eight weeks. CONCLUSIONS: Intervention using an active video game is a promising tool that can improve the gross motor function of children with CP, GMFCS I-II.

Genomic and biological characterization of a new member of the genus Phikmvvirus infecting phytopathogenic Ralstonia bacteria.

Bacterial wilt caused by Ralstonia spp., soil-borne Gram-negative bacteria, is considered one of the most important plant diseases in tropical and subtropical regions of the world. A large number of bacteriophages capable of lysing or physiologically reprogramming cells of Ralstonia spp. have been reported in Asia. Despite the potential use of these organisms in the management of bacterial wilt, information on viruses that infect Ralstonia spp. is nonexistent in the Americas. We isolated a virus that infects Ralstonia spp. from a soil sample in the state of Minas Gerais, Brazil. Microscopy and genomic and phylogenetic analysis allowed us to classify the virus as a member of the family Podoviridae, genus Phikmvvirus. In spite of its relationship to Ralstonia virus RSB3, an Asian isolate, genomic and biological characteristics showed that the virus isolated in Brazil, tentatively named "Ralstonia virus phiAP1" (phiAP1), belongs to a new species. phiAP1 has EPS depolymerase activity and contains two putative virion-associated peptidoglycan hydrolases (VAPGHs), which reveals a robust mechanism of pathogenesis. Furthermore, phiAP1 specifically infects Ralstonia solanacearum, R. pseudosolanacearum and R. syzygii, causing cell lysis, but it was not able to infect thirteen other bacteria that were tested. Together, these characteristics highlight the biotechnological potential of this virus for the management of bacterial wilt.

Energy recovery in high rate algal pond used for domestic wastewater treatment.

High rate algal pond (HRAP) was evaluated according to its energy potential and productivity by two rates, net energy ratio (NER) and specific biomass productivity. All energy inputs were calculated according to one HRAP with pre-ultraviolet disinfection treating anaerobic domestic sewage. The outputs were calculated for two energetic pathways: lipid and biogas production for the raw biomass (RB) and biomass after lipid extraction. The non-polar lipid content in dry biomass was 7.6%, reaching a daily lipid productivity of 0.2 g/m2·day and the biogas production potential was 0.20 m3/kg solids. For the biomass after lipid extraction, the biogas production reached 2.6 m3/kg solids. NER values of 10-3 for the RB were similar for lipids and biogas routes. The specific biomass productivity was 0.7 mg/kJ. For the residual biomass, after lipid extraction, NER value was 10-2 for the integrated route (lipids + biogas) and the specific biomass productivity of the extracted biomass was 0.4 mg/kJ. The best energetic pathway was to integrate both lipids and biogas route.

An Experimental Thermally Deposited Coating for Improved Bonding to Glass-fiber Posts.

PURPOSE: To determine whether an experimental thermally deposited siloxane-methacrylate coating for use in industrial scale applications would improve the bond strength of resin-based materials to glass fiber posts (GFPs) without affecting their mechanical properties. MATERIALS AND METHODS: An experimental 5% (w/v) solution of methacryloxypropyltrimethoxysilane was prepared. Two types of GFPs (Exacto, Angelus; White Post DC, FGM) were divided into the following groups: S: silane; SA: silane and adhesive; HS: 35% H2O2 and silane; HSA: 35% H2O2, silane and adhesive; Exp: siloxane-methacrylate coating (Si-O) via post immersion in experimental solution followed by heating; Exp-S: silane after Si-O treatment; Exp-A: adhesive after Si-O treatment; and Exp-SA: silane and adhesive after Si-O treatment. The posts were positioned in a mold to allow insertion of a dual-curing resin core, serially sectioned into beams, and subjected to microtensile bond strength (µTSB) testing. The three-point bending test and SEM/EDX analysis were used to assess the mechanical and surface properties of untreated GFPs that were etched with H2O2 or treated with Si-O. RESULTS: Surface treatments affected the µTSB only for the Exacto GFPs. The highest µTBS (MPa) was observed in Exp-S and Exp-SA groups, whereas H2O2 etching resulted in intermediate values. The mechanical properties were not affected by surface treatments. Exacto GFPs had significantly higher flexural strength (σf) and flexural modulus (Ef) than did the White Post DC GFPs, but the latter were significantly stiffer (S) than Exacto, regardless of the surface treatment tested. H2O2 promoted morphological changes in post surfaces. The experimental treatment promoted deposition of Si onto the post surface, improving bond strengths of Exacto posts. CONCLUSION: The proposed novel coating technique is a viable procedure for fiber post manufacturers to improve the µTSB of resin-based materials.

Minimally invasive approach in esthetic dentistry: composite resin versus ceramics veneers / Abordagem minimamente invasiva em odontologia estética: resina composta versus facetas cerâmicas

Unsatisfactory anatomical shape of anterior tooth promotes disharmony in the smile esthetics. The conservative dental esthetic reestablishment treatments has been improved and evaluated with the development of adhesive materials. The adhesive dentistry allowed minimally invasive preparation through direct treatments with composite resin and indirect ceramic laminates veneers. These two treatments methods present advantages and disadvantages. The aim of this manuscript is to describe two clinical reports and compare alternatives to rehabilitate the smile esthetic appearance by direct and indirect minimally invasive treatments. In the first case, a 24-years-old patient, female, complained of unsatisfactory anterior maxillary size and incisal wear. After the functional and esthetic planning, nanoparticle composite resin by free hand technique was indicated to rehabilitation. In the second case, a 24-years-old patient, male, reported dissatisfied with his anterior central incisive shape. On clinical examination, maxillary anterior conoid teeth were verified. Based on this evaluation, a conservative treatment using minimally invasive ceramic veneers in maxillary central and lateral incisor and ceramic fragments on canine was planed to the smile rehabilitation. It can be concluded that conservative treatment using direct composite resin restorations and minimum thickness ceramic veneers laminate, even with their specific limitations and advantages, provide satisfactory esthetic and functional treatment results, preserving the dental structure.

Dentes com formato anatômico insatisfatório podem causar desarmonia na estética do sorriso. Os tratamentos para restabelecer a estética do sorriso vêm evoluindo concomitantemente com o desenvolvimento dos materiais dentários. A odontologia estética permite um preparo minimamente invasivo através de resinas compostas e laminados cerâmicos. Estes dois métodos de tratamento apresentam algumas vantagens e desvantagens. O objetivo deste artigo é descrever dois relatos de casos clínicos e comparar alternativas para a reabilitação da estética do sorriso pelos tratamentos minimamente invasivos diretos e indiretos. No primeiro caso, paciente de 24 anos do gênero feminino, estava descontente com o tamanho e com o desgaste incisal dos dentes maxilares anteriores. Após o planejamento funcional e estético foi indicado restauração direta com uma resina nanopartículada pela técnica da mão livre. No segundo caso, paciente de 24 anos do gênero masculino relatou insatisfação com a forma dos incisivos centrais superiores. No exame clínico foi observado incisivos conoídes. Baseado no exame clínico foi planejado um tratamento conservador com laminados cerâmicos nos incisivos centrais e laterais, e fragmentos cerâmicos nos caninos. Pode-se concluir que os tratamentos conservadores utilizando resina composta e laminados cerâmicos, mesmo com suas limitações, promove uma estética satisfatória e resultados funcionais preservando a estrutura dental.

Reabilitação funcional e estética do sorriso û relato de caso / Functional and aesthetic rehabilitation of smile û case report

A constante busca por tratamentos odontológicos estéticos e por um sorriso bonito e harmônico é o que a maioria das pessoas almeja, o que contribui para a realização de procedimentos restauradores que possibilitem mimetização do natural para atingir as expectativas e necessidades dos pacientes. A presença de diastemas pode resultar em problemas funcionais e estéticos. Sendo assim, o presente caso clínico relata reabilitação de um extenso diastema entre os incisivos centrais superiores, após intervenção cirúrgica para remoção do freio labial e clareamento dental. Foram realizadas restaurações diretas minimamente invasivas nos dentes anteriores, com resina composta nanoparticulada. O acabamento e polimento foram realizados de forma a evidenciar anatomia e textura de superfície dos dentes. Em conclusão, o tratamento realizado utilizou materiais com comportamento biomecânico favorável, estabelecendo função, harmonia do sorriso e resultado estético satisfatório...

The constant search for dental aesthetic treatments in order to achieve a nice and harmonic smile has contributed to the development of restorative procedures enabling mimicry of natural teeth to meet expectations and needs of patients. The presence of diastemas can result in functional and aesthetic problems. Therefore, the present clinical case reports rehabilitation of a large diastema between the maxillary central incisors, after surgery for removal of labial frenum and tooth bleaching. Minimally invasive direct restorations were performed in anterior teeth with nanofilled composite resin. Finishing and polishing were done in order to demonstrate anatomy and surface texture of the teeth. In conclusion, the treatment used materials with biomechanical behavior, setting function, harmony of the smile and satisfactory aesthetic result...

Harmonização do sorriso com facetas diretas em resina composta: relato de caso / Smile harmonization with direct composite resin: a case report

Atualmente é possível ter maior previsibilidade do tratamento reabilitador com utilização de materiais com propriedades que biomimetizam os tecidos dentários perdidos. Este trabalho objetiva relatar o caso clínico de um paciente jovem insatisfeito com o aspecto de seu sorriso, o qual apresentava comprometimento do formato e da coloração dos dentes anterossuperiores. Para a reabilitação foram realizados planejamento reverso, com protocolo fotográfico, wax-up e mock-up, clareamento dental externo pela técnica de consultório e reanatomização dentária com facetas diretas em resina composta nos dentes 13 ao 23, pela técnica de estratificação. Em conclusão, esta reabilitação funcional e estética proporcionou ao paciente harmonia em seu sorriso, autoestima e satisfação com o resultado final alcançado...

Currently it is possible to have greater predictability of the rehabilitation treatment, through the use of materials with properties that resemble the lost dental tissue. This work aims to report the case of a young patient unsatisfied with the appearance of her smile, with format change and discoloration of the anterior teeth. For the rehabilitation, a reverse planning was carried out, through the use of a photographic protocol, wax-up and mock-up, external tooth bleaching and direct restorations on teeth #13 to #23, by a layering technique. In conclusion, this functional and aesthetic rehabilitation provided the patient’s smile harmony, self-esteem and satisfaction with the final result achieved...

Reabilitação estética de dente fraturado û relato de caso / Aesthetic rehabilitation of fractured tooth û case report

Traumatismo em dentes anteriores é queixa comum nos consultórios odontológicos e pode estar associado a fraturas coronárias, o que resulta em comprometimento da função e estética. As principais técnicas para reconstrução de dentes fraturados utilizam materiais restauradores adesivos diretos por possuírem propriedades físicas e mecânicas semelhantes à estrutura dentária, além de ser técnica minimamente invasiva. O presente artigo relata um caso clínico de restauração em dente anterior fraturado, utilizando resina composta nanoparticulada associada ao clareamento dental. O tratamento realizado possibilitou restabelecer função e devolver a harmonia e estética do sorriso...

Traumatic injuries in anterior teeth are a common complaint in the dental office. These traumas can result in crown fractures causing impairment of aesthetics and function. The main techniques for reconstruction of fractured teeth include the use of direct adhesive restorative materials because of their physical and mechanical properties that are similar to the tooth structure and minimally invasive technique. This article reports a clinical case of restoration in fractured anterior teeth using composite resin with dental bleaching. The result was satisfactory because they restored function and a harmonic smile...

Use of sensory information during postural control in children with cerebral palsy: systematic review.

Impairments in sensory processing in children with cerebral palsy (CP) appear to be a cause of the postural control deficits they present and may affect function and participation in daily activities. Understanding the role of sensory processing in postural control can better inform their rehabilitation. Thus, the authors aimed to systematically review the literature concerning effects of sensory information manipulation on postural control in children with CP. A tailored search strategy in relevant databases identified 11 full-text reports that fulfilled the predefined inclusion and exclusion criteria. Sensory information affects postural control in children with CP. These children are less responsive to sensory input, and therefore are less able to perform adjustments during sensory perturbation. They exhibit less postural stability in the presence of sensory conflicts. The most commonly studied sources of sensory data are visual and somatosensory information, particularly when processed under static conditions. There are no studies addressing sensory information manipulation on postural control during the performance of functional activities. Further studies addressing manipulation of new sources of sensory cues on postural control are required.

Bimanual coordination in typical and atypical infants: movement initiation, object touching and grasping.

The development of bimanual actions reflects perceptual, motor and cognitive processes, as well as the functional connectivity between brain hemispheres. We investigated the development of uni- and bimanual actions in typically-developing (TD) infants and infants with Down syndrome (DS) while they reached for objects with varying sizes. Eight TD infants and seven infants with DS (ages 4-8 months) were tested at several stages of reaching experience. Movement strategies at movement initiation, object touching and grasping were recorded. With reaching experience, typical infants increased ability to anticipate reaching strategies, and independent use of the hands according to task demands. Strategies used by infants with DS were mostly compensatory rather than anticipatory, and showed a weaker tendency for interlimb coupling at early ages. These differences may underlie functional limitations, and should be subject to early intervention.

Ultrastructure and immunofluorescence of the midgut of Bombus morio (Hymenoptera: Apidae: Bombini).

Bumblebees are widely distributed across the world and have great economic and ecological importance as pollinators in the forest as well as in agriculture. The insect midgut consists of three cell types, which play various important roles in digestion, absorption, and hormone production. The present study characterized the anterior and posterior midgut regions of the bumblebee, Bombus morio. The digestive, regenerative and endocrine cells in the midgut showed regional differences in their number, nuclear size, as well as the size of the striated border. Ultrastructurally, the digestive cells contained many mitochondria and long microvilli; however, in the anterior midgut region, these cells showed dilated basal labyrinths with a few openings for the hemocoel, whereas the labyrinths of the basal posterior region remained inverse characteristics. Thus, the characterization of the midgut of B. morio supported an ecto-endoperitrophic circulation, contributing to a better understanding of the digestive process in this bee.

Intra-radicular dentin treatments and retention of fiber posts with self-adhesive resin cements

The aim of this study was to evaluate the effect of treating intraradicular dentin with irrigating solutions on the retention of glass-fiber posts luted with self-adhesive resin cement. Bovine incisors were endodontically treated, and 9-mm-deep postholes were prepared. Before inserting the cement, the root canals were irrigated with various solutions: 11.5% polyacrylic acid for 30 s, 17% EDTA for 60 s, or 5% NaOCl for 60 s, respectively. Irrigation with distilled water was used in the control group. After all specimens had been rinsed with distilled water, the excess moisture was removed and the posts were luted using either BisCem (Bisco) or RelyX Unicem clicker (3M ESPE). Seven days after luting, the specimens were sectioned transversally into 1-mm-thick slices, which were submitted to push-out testing on a mechanical testing machine. Bond strength data (n = 6 per group) were analyzed by two-way ANOVA and Student-Newman-Keuls' test (α = 0.05). For Unicem, EDTA showed lower bond strength than the other solutions, which had similar results. For BisCem, EDTA showed higher bond strength than the other treatments, while application of NaOCl yielded higher bond strength than polyacrylic acid whereas the control group had intermediate results. In conclusion, irrigating root canals before insertion of self-adhesive resin cements, especially EDTA, might interfere with retention of the fiber posts.