Fleck-like lesions in CEP290-associated leber congenital amaurosis: a case series.

PURPOSE: To provide a detailed ophthalmic phenotype of a small cohort of patients with Leber Congenital Amaurosis (LCA) caused by mutations in CEP290 (CEP290-LCA) with a focus on elucidating the origin of yellow-white lesions observed in 30% of patients with this condition. METHODS: This is a retrospective review of records of five patients with CEP290-LCA. Patients had comprehensive ophthalmic evaluations. Visual function was assessed with full-field electroretinograms (ffERGs) and full-field sensitivity testing (FST). Multimodal imaging was performed with spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) with short- (SW) and near-infrared (NIR) excitation wavelengths. RESULTS: All patients showed relative structural preservation of the foveal and near midperipheral retina separated by a pericentral area of photoreceptor loss. Yellow-white, fleck-like lesions in an annular distribution around the near midperiphery co-localized with hyperreflective lesions on SD-OCT. The lesions located between the inner segment ellipsoid signal and the apical retinal pigment epithelium (RPE). The inner retina was normal. Longitudinal observations in one of the patients indicates the abnormalities may represent an intermediate stage in the degenerative process between the near normal appearing retina previously documented in young CEP290-LCA patients and the pigmentary retinopathy observed along the same region in older individuals. CONCLUSIONS: We speculate that fleck-like lesions in CEP290-LCA correspond to malformed, rudimentary or degenerated, including shed, photoreceptor outer segments. The topography and possible origin of the abnormalities may inform the planning of evolving genetic therapies for this disease.

A novel nepovirus causing a chlorotic fleck disease on common bean (Phaseolus vulgaris L.).

Two common bean leaf samples from Ethiopia that had shown chlorotic fleck and veinal mosaic symptoms but tested ELISA-negative for known viruses were mechanically transmitted to herbaceous hosts to obtain virus isolates ET-773/4 and ET-779. Virus purification from Chenopodium quinoa systemically infected with ET-773/4 yielded icosahedral particles measuring ~ 30 nm in diameter and containing a single capsid protein of ~ 58 kDa, suggesting a nepovirus infection. Analysis of nucleotide sequences generated from RNA1 and RNA2 of the isolates indicated that they represent a distinct virus species in the genus Nepovirus. Surprisingly, the most closely related sequence in the GenBank database was that of Hobart nepovirus 3, an incompletely described metagenomic sequence obtained from honey bees in Tasmania. This new nepovirus from Ethiopia is provisionally named "bean chlorotic fleck virus".

Evaluation of Tensile Bond Strength of Metallic Prefabricated Posts Cemented with Different Luting Agents

Abstract Objective: To assess the tensile bond strength of prefabricated metal posts cemented with different luting agents. Material and Methods: Fifty single-rooted endodontically treated human teeth had their crowns cut, mounted into acrylic-resin blocks and then an 8mm depth post space were prepared. Prefabricated cylindrical metal posts were cemented using different luting agents: a zinc phosphate cement (SS White), a conventional glass ionomer cement (Vidrion C), two resin-modified glass ionomer cements (Vitremer and RelyX Luting 2) and a resin cement (RelyX ARC). Samples were stored in distilled water for seven days and then submitted to a tensile bond strength test until complete dislocation of the post. One-way analysis of variance and Tukey test for pairwise multiple comparisons were used to evaluate differences between luting agents. Results: Tensile bond strength was 563.88±203.41 N for zinc phosphate cement, 336.86 ± 137.64 N for Vidrion C, 515.24 ± 239.48 N for Vitremer, 828.47±433.99 N for RelyX Luting 2 and 1262.51 ± 356.29 for RelyX ARC. The Relyx ARC presented the highest tensile bond strength regard the luting agent tested (p< 0.05). Conclusion: RelyX ARC presented the higher tensile bond strength compared to the other luting agents evaluated.

Cytotoxicity, Morphology and Chemical Composition of Two Luting Cements: An in Vitro Study

Abstract Objective: To assess the cytotoxicity, surface morphology, elemental compositions and chemical characterization of two commonly used luting cement. Material and Methods: The two luting types of cement used were Elite Cement® and Hy-Bond Resiglass®. Freshly mixed (n=6) and set form (n=6) of each cement was placed in medium to obtain extracts. The extract from each sample was exposed to L929 mouse fibroblasts (1x104cells/well). Alamar Blue Assay assessed cell viability. Surface morphology and elemental composition were evaluated using scanning electron microscopy and energy dispersive spectroscopy. The chemical characterization was performed by Fourier Transform Infrared Spectroscopy. One-way ANOVA and post-hoc Tukey analysis were conducted to assess results. Results: Hy-Bond Resiglass® was the more cytotoxic of the two types of cement in both freshly mixed (68.10 +5.16; p<0.05) and set state (87.58 +4.86; p<0.05), compared to Elite Cement® both freshly mixed (77.01 +5.45; p<0.05) and set state (89.39 +5.66; p<0.05). Scanning electron microscopy revealed a more irregular and porous structure in Hy-Bond Resiglass® compared to Elite Cement®. Similarly, intense peaks of aluminium, tungsten and fluorine were observed in energy dispersive spectroscopy in Hy-Bond Resiglass. Conclusion: All these three elements (aluminium, tungsten and fluorine) have cytotoxic potential. The Fourier transform infrared spectroscopy revealed the presence of hydroxyethyl methacrylate in Hy-Bond Resiglass®, which has a cytotoxic potential.

Fracture resistance of metal-ceramic crown copings cemented to two types of intra-radicular posts / Resistência à fratura de copings de coroa metalocerâmica cimentados sobre dois tipos de retentores intrarradiculares

Introduction: Endodontically treated teeth are more susceptible to root fracture than vital teeth. In order to reduce the risk of fracture, the use of intra-radicular posts and crowns is indicated. However, their own fracture resistance remains unclear. Objective: To analyze the behavior of metal-ceramic crown copings cemented to two types of intra-radicular posts under tensile stress. Material and method: Sixteen metal-ceramic crown copings cemented with zinc phosphate cement to cast metal posts and cores (group 1, n = 8) or with self-adhesive resin cement to glass-fiber posts rebased with composite resin (group 2, n = 8) were subjected to tensile testing after endodontic treatment and standardized preparation. Failure occurred when the crown coping and/or post-core assembly fractured and/or detached. Result: In group 1, after the application of a mean tensile load of 46.83 N, 7 crown copings and metal cores separated as a whole, while in 1 specimen the coping detached from the metal core. In group 2, a mean tensile load of 127.68 N resulted in glass-fiber post fracture, and in 1 case the entire crown-post-core assembly was detached. Tensile strength differed significantly between the two groups (p = 0.0085). Conclusion: Our findings suggest that metal-ceramic crown copings cemented with self-adhesive resin cement show strong adhesion to composite resin cores associated with glass-fiber posts, thus providing a safe alternative to the use of cast metal posts and cores.

Introdução: Os dentes tratados endodonticamente são mais suscetíveis à fratura radicular do que os dentes vitais. Para reduzir o risco de fratura, indica-se o uso de coroas e retentores intrarradiculares. No entanto, ainda não está clara a resistência dessas estruturas a fraturas. Objetivo: Analisar o comportamento de copings de coroa metalocerâmica cimentados com dois tipos de retentores intrarradiculares sob tensão de tração. Material e método: Dezesseis copings de coroa metalocerâmica cimentados com cimento de fosfato de zinco para núcleos e pinos de metal fundido (grupo 1, n= 8) ou com cimento resinoso autoadesivo para núcleos de resina composta com pinos de fibra de vidro (grupo 2, n= 8) foram submetidos a testes de tração após tratamento endodôntico e preparo padronizado. Houve falha quando o coping da coroa e/ou a estrutura pino-núcleo se quebrou e/ou se soltou. Resultado: No grupo 1, após a aplicação de uma carga de tração média de 46,83 N, 7 copings e núcleos metálicos se separaram completamente, enquanto em 1 espécime o coping se soltou do núcleo metálico. No grupo 2, uma carga de tração média de 127,68 N resultou em fratura do pino de fibra de vidro, e em 1 caso toda a estrutura coroa-pino-núcleo se soltou. A resistência à tração foi significativamente diferente entre os dois grupos ( P= 0,0085). Conclusão: Nossos achados sugerem que copings de coroa metalocerâmica cimentados com cimento resinoso autoadesivo apresentam forte adesão aos núcleos de resina composta associados aos pinos de fibra de vidro, proporcionando uma alternativa segura ao uso de retentores de metal fundido.

Effect of 830 nm Diode Laser Irradiation of Root Canal on Bond Strength of Metal and Fiber Post.

OBJECTIVE AND BACKGROUND: The correct selections of the cementing agent, the endodontic post material and placement protocol are critical to provide an increased longevity of the teeth that went through endodontic treatment. The irradiation with diode laser before post cementation, can promote an antimicrobial effect. However, there is a lack of information about the effect of 830 nm diode laser on the post bond strength. This study analyzed the effect of dentin root canal irradiation with high-intensity diode laser, at 830 nm, operating in continuous or pulsed mode, on the retention of metal or fiber posts, cemented with self-etching resinous composite (Panavia F) and zinc phosphate cement (ZnPO4). MATERIALS AND METHODS: Human roots were irradiated with diode laser (continuous and pulsed mode). The fiber posts were luted with Panavia F and the metal posts with Panavia F or ZnPO4 cement. Specimens were sectioned into three sections (cervical, middle, and apical). The bond strength was measured by a push-out mechanical analysis. For the statistical analysis, a three-way ANOVA test was applied following a Tukey's pairwise comparison with a significance level of p = 0.05. RESULTS: The irradiated groups presented higher bond strength compared with nonirradiated group (p < 0.05), and the cervical and middle thirds presented higher on bond strength than the apical. The association of metal post and Panavia F presented higher bond strength when irradiated on continuous mode (p < 0.05). Fiber post and Panavia F presented higher bond strength associated to pulsed mode. The mode seems not to make a significant difference. CONCLUSIONS: These results corroborate the importance of the post bond to dentin and root canal debris removal to increase the tooth longevity. It was shown that the dentin to post bond strength were enhanced by the diode laser irradiation either on continuous or pulsed modes.

Influência do agente cimentante e desajuste interno na adaptação marginal de coroas em resina nanocerâmica / Influence of the cement agent and internal mismatch in the marginal adaptation of nanoceramic resins crowns

A adaptação marginal é um dos requisitos fundamentais para a longevidade e o sucesso das restaurações. O objetivo desse estudo foi avaliar a influência do desajuste interno associado à diferentes agentes cimentantes na desadaptação marginal de coroas em resina nanocerâmica (Lava Ultimate 3M ESPE) confeccionadas pelo sistema CAD-CAM. A partir do escaneamento de um preparo de coroa total em um pré-molar, foram obtidos 36 modelos em metal. Esses foram divididos em seis grupos de acordo com o desajuste interno (70 µm ou 100 µm) e o cimento (Fosfato de zinco- SS White, Cimento de ionômero de vidro- Ketac Cem 3M/ESPE e Cimento resinoso- Relyx Ultimate 3M/ESPE). Após escaneamento de todos os modelos as coroas foram confeccionadas a partir da fresagem de blocos de resina nanocerâmica (Lava Ultimate 3M/ESPE). Com auxílio de microscópio óptico comparador (40X) foram medidas as desadaptações marginais prévia e posteriormente à cimentação, sendo considerados 8 pontos ao longo do término em todas as faces do corpo de prova. Os valores obtidos após serem submetidos aos testes two-way anova e teste t, demonstraram que as coroas confeccionadas com desajuste interno de 70 µm apresentam desadaptação marginal inferior estatisticamente significante às coroas com desajuste interno de 100 µm. Para o desajuste interno de 70 µm o grupo do cimento fosfato de zinco apresentou o menor gap marginal, sendo que este valor não foi estatisticamente diferente em relação ao grupo do Ketac Cem. Ainda com esse desajuste, o grupo do Ketac Cem não apresentou diferença estatística significante em relação ao grupo do Relyx Ultimate, no entanto esse último promoveu "gap" marginal estatisticamente maior em relação ao grupo do cimento fosfato de zinco. Para o desajuste interno de 100 µm não houve diferença estatisticamente significante no "gap" marginal entre os três cimentos avaliados. O presente estudo demonstrou através da metodologia utilizada, que a menor desadaptação marginal observada nas restaurações de Lava Ultimate, foi proveniente do desajuste interno de 70 µm. Neste grupo os cimentos de fosfato de zinco e de ionômero de vidro demonstraram melhor comportamento comparado ao cimento resinoso, embora o cimento de ionômero de vidro numericamente, mas não estatisticamente tenha apresentado resultado inferior ao do fosfato de zinco

The marginal adaptation is one of the basic requirements for the longevity and success of restorations. The aim of this study was to evaluate the influence of the internal imbalances associated with different luting agents on marginal leakage of crowns Nanoceramic resin ( Lava Ultimate 3M ESPE) made by CAD-CAM system. From the scanning of a full crown preparation in a pre molar were obtained 36 metal models. These were divided into six groups according to the internal imbalances ( 70 or 100 micrometres) and cement (SS White Zinc phosphate, glass ionomer cemet Ketac Cem 3M/ Espe and resinous cement Relyx Ultimate 3M / Espe). After scanning all models crowns were made from milling Nanoceramic resin blocks (Lava Ultimate 3M / Espe). With the aid of optical comparator microscope (40X) were measured prior marginal mismatches and after the cementation, being considered 8 points along the end in all specimen faces. The values were submitted to ANOVA two-way test and t test. Results showded that crowns made with internal imbalances of 70 uM show statistically significant lower marginal leakage to the crows with internal imbalances of 100 micrometres. For the internal imbalances 70 uM zinc phosphate cement group showed the lowest "gap" marginal, and this figure does not show a statistically significant difference compared to Ketac Cem gropu. Even with this misfit, Ketac Cem group showed no statistically significant difference in relation to Relyx Ultimate group, though the latter showed a statistically significant difference compared to zinc phosphate cement group. For the internal imbalances of 100 micrometres there was no statistically significant difference in the "gap" marginal among the three cements. This study demostrated through the methodology used, the lower marginal leakage oberved in Lava Ultimate restorations, was from the inner misfit 70 micrometers...

Retrievability of implant-supported crowns when using three different cements: a controlled clinical trial.

PURPOSE: The purpose of this study was to analyze the removal of implant-supported crowns retained by three different cements using an air-accelerated crown remover and to evaluate the patients' response to the procedure. MATERIALS AND METHODS: This controlled clinical trial was conducted with 21 patients (10 women, 11 men; mean age: 51 ± 10.2 years) who had received a total of 74 implants (all placed in the posterior zone of the mandible). Four months after implant surgery, the crowns were cemented on standard titanium abutments of different heights. Three different cements (two temporary: Harvard TEMP and Improv; and one definitive: Durelon) were used and randomly assigned to the patients. Eight months later, one blinded investigator removed all crowns. The number of activations of the instrument (CORONAflex, KaVo) required for crown removal was recorded. The patients completed a questionnaire retrospectively to determine the impact of the procedure and to gauge their subjective perception. A linear regression model and descriptive statistics were used for data analysis. RESULTS: All crowns could be retrieved without any technical complications or damage. Both abutment height (P = .019) and cement type (P = .004) had a significant effect on the number of activations, but the type of cement was more important. An increased total number of activations had no or only a weak correlation to the patients' perception of concussion, noise, pain, and unwillingness to use the device. CONCLUSIONS: Cemented implant crowns can be removed, and the application of an air-accelerated device is a practicable method. A type of cement with appropriate retention force has to be selected. The impact on the patients' subjective perception should be taken into account.

Capacidad de sellado de tres agentes cementantes para restauraciones coronarias indirectas / Sealing ability of three luting agents used for cementation of indirect coronal restorations

Objetivo: comparar ex vivo, por medio de un modelo de filtración bacteriana, la capacidad de sellado de un ionómero vítreo modificado con resinas, de un ionómero vítreo convencional y de un cemento de fosfato de cinc, utilizados para la cementación de coronas coladas (AU). Materiales y métodos: un total de 30 premolares humanos sanos, extraídos, fueron preparados de forma estandarizada para recibir una corona metálica con terminación en chamfer sobre dentina. Se realizaron impresiones, se vaciaron en densita tipo IV, se enceraron y se colaron en aleación de oro tipo III. Luego fueron separadas al azar en tres grupos de 10 (n=10) especímenes cada uno. Las coronas del grupo 1 fueron cementadas con Rely-X Luting Plus (3M/ESPE); y las del grupo 2, con Ketac-Cem (3m/ESPE); y las del grupo 3 (control), con el cemento de fosfato de cinc Harvard Cement (Harvard Debtal International GmbH, Hoppengarten, Alemania). Todos los especímenes fueron termociclados. Posteriormente, la superficie metálica oclusal fue reducida 1 mm hasta exponer la dentina, y las muestras se esterilizaron en autoclave. El proceso de filtración se realizó por medio de un sistema de doble cámara con medio de cultivo. El medio de la cámara superior se inoculó con E. faecalis y el sistema fue incubado durante 60 días. En la cámara inferior, la filtración bacteriana se controló diariamente. Los datos registrados fueron analizados por medio de las pruebas de Kaplan-Meyer y de Fischer, con un nivel de significación de P<0,05. Resultados: el tiempo de supervivencia para Rely-X Luting Plus no pudo ser estimado, ya que fue superior a los 60 días, tiempo máximo de duración de la experiencia. Para Ketac-Cem fue de 60 días, con un intervalo de confianza (95 por ciento) de 29,6-90,4. Y para Harvard Cement fue de 40 días, con un intervalo de confianza de 32,6-47,4. Las diferencias entre los grupos fueron estadísticamente significativas. Conclusión: Rely-X Plus demostró una capacidad de sellado superior.

In vitro comparisons of casting retention on implant abutments among commercially available and experimental castor oil-containing dental luting agents.

STATEMENT OF PROBLEM: Although cement-retained implant prostheses are widely used, the quantification of optimal retention remains controversial, and new dental luting agents should be evaluated. PURPOSE: The purpose of this study was to compare, in vitro, the casting retention on implant abutments after cementation with 3 commercially available luting agents and an experimental luting agent (castor oil polyurethane, COP) with variable weight percentages (wt%) of calcium carbonate (CaCO3). MATERIAL AND METHODS: Seventy-two palladium-silver cast copings were fabricated and divided into 6 groups: Temp Bond interim cement (TB); zinc phosphate cement (ZP); Rely X ARC resin cement (RX); pure COP (COP); COP + 10% wt% CaCO3 filler (COP 10); and COP + 50% wt% CaCO3 filler (COP 50). After cementation, the specimens were stored in distilled water at 37°C for 24 hours and subjected to removal force tests in a universal testing machine (5 kN; 0.5 mm/min). Statistical analyses were performed with the Kruskal-Wallis and Student-Newman-Keuls tests (α=.05). RESULTS: The median values of casting retention (N) were as follows: TB=57.20 ±10.4; ZP=343.56 ±50.3; RX=40.07 ±9.7; COP=258.98 ±41.4; COP 10=466.57 ±79.3; and COP 50=209.63 ±31.4. The Kruskal-Wallis test showed significant differences among the groups (P<.01). TB and RX had the lowest mean retention values; COP, COP 10, and COP 50 were equal to ZP, and COP 10 had the highest retention. CONCLUSIONS: The casting retention on implant-abutments provided by COP was similar to that of copings cemented with zinc phosphate and may be influenced by the addition of calcium carbonate.

Treatment of congenitally missing maxillary lateral incisors: an interdisciplinary approach.

Dentists have several treatment options when restoring patients with congenitally missing maxillary lateral incisors. Endosseous implant therapy combined with orthodontics can achieve predictable outcomes while meeting patient expectations. This case report exhibits an interdisciplinary approach involving orthodontics, implant surgery, and prosthodontics to resolve this common dental concern.

A 5-year prospective radiographic evaluation of marginal bone levels adjacent to parallel-screw cylinder machined-neck implants and rough-surfaced microthreaded implants using digitized panoramic radiographs.

OBJECTIVE: The purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level over five years of functional loading. MATERIALS AND METHODS: From January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until December 2011. Marginal bone level was radiographically determined at six time points: implant placement (baseline), after the healing period, after six months, and at two years, three years, and five years follow-up. RESULTS: Median follow-up time was 5.2 years (range: 5.1-5.4). The machined-neck group had a mean crestal bone loss of 0.5 mm (0.0-2.3) after the healing period, 1.1 mm (0.0-3.0) at two years follow-up, and 1.4 mm (0.0-2.9) at five years follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (-0.4 to 2.0) after the healing period, 0.5 mm (0.0-2.1) at two years follow-up, and 0.7 mm (0.0-2.3) at five years follow-up. The two implant types showed significant differences in marginal bone levels. CONCLUSIONS: Rough-surfaced microthreaded design caused significantly less loss of crestal bone levels under long-term functional loading in the mandible when compared to machined-neck implants.

Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement

The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not well-documented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12): GA, control (without finishing); GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the core-finishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study, it was demonstrated that the core-finishing procedures and time intervals that elapsed after luting did not appear to affect the retention of cast posts-and-cores when zinc phosphate cement was used.

Comparison of different ultrasonic vibration modes for post removal

This in vitro study compared different ultrasonic vibration modes for intraradicular cast post removal. The crowns of 24 maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the canals were treated endodontically. The post holes were prepared and root canal impressions were taken with self-cured resin acrylic. After casting, the posts were cemented with zinc phosphate cement. The samples were randomly distributed into 3 groups (n=8): G1: no ultrasonic vibration (control); G2: tip of the ultrasonic device positioned perpendicularly to core surface and close to the incisal edge; and G3: tip of the ultrasonic device positioned perpendicularly to core surface at cervical region, close to the line of cementation. An Enac OE-5 ultrasound unit with an ST-09 tip was used. All samples were submitted to the tensile test using an universal testing machine at a crosshead speed of 1 mm/min. Data were subjected to one-way ANOVA and Tukey's post-hoc tests (α=0.05). Mean values of the load to dislodge the posts (MPa) were: G1 = 4.6 (± 1.4) A; G2 = 2.8 (± 0.9) B, and G3= 0.9 (± 0.3) C. Therefore, the ultrasonic vibration applied with the tip of device close to the core's cervical area showed higher ability to reduce the retention of cast post to root canal.

Este estudo in vitro comparou diferentes modos de vibração ultra-sônica na remoção de pinos intra-radiculares fundidos. As coroas de 24 caninos superiores foram removidas, as raízes foram incluídas em blocos de resina acrílica e tratadas endodonticamente. Os espaços para os pinos intra-radiculares foram preparados e depois moldados com resina acrílica autopolimerizável. Após a fundição, os pinos intra-radiculares foram cimentados com cimento de fosfato de zinco. As amostras foram distribuídas aleatoriamente em três grupos (n=8): G1: sem vibração ultra-sônica (controle), G2: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo e perto da borda incisal e G3: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo na região cervical, perto da linha de cimentação. Uma unidade de ultra-som Enac OE-5 com uma ponta ST-09 foi usada. Todas as amostras foram submetidas ao teste de tração utilizando máquina universal de ensaios a uma velocidade de 1 mm/min. Os dados foram submetidos aos testes ANOVA e Tukey post-hoc (α = 0,05). Os valores médios de carga para deslocar os pinos (MPa) foram: G1 = 4,6 (± 1,4) A; G2 = 2,8 (± 0,9), B e G3 = 0,9 (± 0,3) C. Portanto, a vibração ultra-sônica aplicada com a ponta do dispositivo perto da zona cervical do núcleo apresentou maior capacidade de reduzir a retenção de pinos metálicos fundidos no canal radicular.

Estudo dos contatos oclusais em balanceio quanto a frequência, intensidade e método de avaliação em indivíduos jovens / Study of occlusal contacts in swing as the frequency, intensity and method of assessment in young individuals

Um fator importante no estudo da oclusão refere-se à correta detecção da presença de contatos oclusais no lado de balanceio, sua intensidade e localização. No entanto, a maioria dos estudos que se propuseram a detectar a presença de contatos em balanceio, o fizeram utilizando papel carbono em movimentos conduzidos de máxima intercuspidação até topo-a-topo. O objetivo deste estudo foi estudar a frequência de contatos oclusais detectados no lado de balanceio em 42 indivíduos jovens, com idade média de 26 anos comparando dois métodos: 1- durante o ato mastigatório, utilizando como material de registro uma mistura de verniz cavitário e pó de fosfato de zinco; 2- durante movimentos conduzidos, utilizando como material de registro papel carbono. A frequência de contatos oclusais no lado de balanceio durante o ato mastigatório e utilização de verniz, foi de 100%, sendo que 97 % dos pacientes possuíam contatos bilaterais e 3 % apresentaram apenas contatos unilaterais. A frequência de contatos oclusais no lado de balanceio para os mesmos indivíduos, porém, com a utilização de papel carbono e movimentos conduzidos foi de 76%, sendo que 64% dos pacientes possuíam contatos bilaterais, 12% apresentavam apenas contatos unilaterais e 24% dos pacientes não possuíam contatos. Com relação aos métodos empregados, a mistura de verniz cavitário e pó do fosfato de zinco mostrou um número maior estatisticamente significante de marcações comparado ao papel carbono. De acordo com a metodologia empregada, concluiu-se que o verniz se mostrou mais sensível e eficaz por detectar uma quantidade maior de contatos oclusais comparado ao papel carbono.

An important factor in the study of occlusion refers to the correct detection of the occlusal contacts in the balancing side, intensity and location. However, most studies that proposed itself on detect the presence of balancing contacts used carbon paper led movements in maximal intercuspal to topo a topo. The objective of this study was to evaluate the frequency of occlusal contacts in the balancing side in 42 young people, with a mean age of 26 years through two methods: 1 - during the masticatory act, using as registration material a mixture of cavity varnish and dust zinc phosphate, 2 - during movements performed, using as registration material carbon. And assess if the methods show similar results. The frequency of occlusal contacts on the balancing side during the masticatory act and using of varnish, was 100% and 97% of patients had bilateral contacts and 3% had presented only unilateral contacts. The frequency of occlusal contacts on the balancing side for the same individuals, however, by analyzing method with carbon and led movements was 76% and 64% of patients had bilateral contacts, 12% had only unilateral and 24 contacts % of patients had no relation to contacts. Regarding the method study, it presented statistical differences between the methods, regardless of the side studied. All differences point to a greater number of contacts on the coating method, indicating that in general this method detects more markings than the carbon method. According to the methodology, it concluded that the method was more sensitive varnish that carbon method for being able to detect more numbers occlusal contacts than carbon.

Surface roughness of orthodontic band cements with different compositions

OBJECTIVES: The present study evaluated comparatively the surface roughness of four orthodontic band cements after storage in various solutions. MATERIAL AND METHODS: Eight standardized cylinders were made from 4 materials: zinc phosphate cement (ZP), compomer (C), resin-modified glass ionomer cement (RMGIC) and resin cement (RC). Specimens were stored for 24 h in deionized water and immersed in saline (pH 7.0) or 0.1 M lactic acid solution (pH 4.0) for 15 days. Surface roughness readings were taken with a profilometer (Surfcorder SE1200) before and after the storage period. Data were analyzed by two-way ANOVA and Tukey's test (comparison among cements and storage solutions) or paired t-test (comparison before and after the storage period) at 5 percent significance level. RESULTS: The values for average surface roughness were statistically different (p<0.001) among cements at both baseline and after storage. The roughness values of cements in a decreasing order were ZP>RMGIC>C>R (p<0.001). After 15 days, immersion in lactic acid solution resulted in the highest surface roughness for all cements (p<0.05), except for the RC group (p>0.05). Compared to the current threshold (0.2 µm) related to biofilm accumulation, both RC and C remained below the threshold, even after acidic challenge by immersion in lactic acid solution. CONCLUSIONS: Storage time and immersion in lactic acid solution increased the surface roughness of the majority of the tested cements. RC presented the smoothest surface and it was not influenced by storage conditions.

Microleakage of adhesive and nonadhesive luting cements for stainless steel crowns.

PURPOSE: This study's purpose was to compare the ability of 5 luting cements to reduce microleakage at stainless steel crown (SSC) margins on primary molar teeth. METHODS: Standard preparations were performed on 100 extracted primary molar teeth for SSC restoration. After fitting SSCs, samples were randomly divided into 5 groups of 20 teeth each, which were cemented with nonadhesive cement consisting of polycarboxylate (PC) or zinc phosphate (ZP), or with adhesive cement consisting of glass ionomer (GIC), resin-modified glass ionomer cement (RMGIC), or RMGIC with a bonding agent (RMGIC+DBA). After aging and thermocycling, the specimens were placed in 1% methylene blue, sectioned, and evaluated under a digital microscope. The data were compared between groups with the t test, analysis of variance, and the least significant difference test. RESULTS: Microleakage with adhesive cements was significantly lower than with nonadhesive cements (P<.05). Differences between cements were statistically significant at P<.001. RMGIC+DBA showed the lowest microleakage, followed in increasing order by RMGIC, GIC, and ZP. The PC cement showed the greatest microleakage. CONCLUSIONS: Adhesive cements were more effective in reducing microleakage in stainless steel crowns than nonadhesive cements. Use of a bonding agent with a resin-modified glass ionomer cement yielded better results than using the latter alone.

Comparing the retention of cast posts cemented with three different kinds of cement / Comparação da retenção de pinos fundidos cimentados com três tipos de cimento

Objective: To check and compare the retention of cast posts cemented with three different kinds of cement. Method: Forty five 45 human permanent maxillary incisors were randomly divided into three groups of 15 teeth. Root canals were prepared for the cast posts up to 8.5mm in length. The cast post obtained randomly were cemented with the help of the three cements (Zinc Phosphate, Glass-ionomer and resin modified Glass-ionomer [hybrid] cement). After cementation, the samples were stored in a physiological solution for seven days, after which we concluded the measure of retentive strength with the help of the universal testing machine (Zwick num. 112627, Ulm-Germany). Results: The hybrid cement has the greatest means value for retention and it is 312.90 N. It is followed by the Glass-ionomer cement with 272.40 N, while the Zinc Phosphate has the least, at 312.90 N. The statistical analysis shows that there is a statistical difference in the retention strength between the Zinc Phosphate cement and the Glass-ionomer (p<0.01), between the Zinc Phosphate cement and the hybrid cement (p<0.01). Conclusion: A significant statistical discrepancy was not manifested between the Glass-ionomer cement and the hybrid cement even though the difference in retention strength for these two cements was around 40 N.

Objetivo: Verificar e comparar a retenção de pinos fundidos cimentados com três diferentes tipos de cimento. Método: Quarenta e cinco incisivos superiores permanentes humanos foram divididos aleatoriamente em três grupos de 15 dentes cada um. Os canais radiculares foram preparados para receberem pinos fundidos de até 8.5 mm de comprimento. Os pinos foram cimentados com um dos três tipos de cimentos a seguir: cimento de fosfato de zinco, cimento de ionômero de vidro e cimento de ionômero de vidro modificado por resina (híbrido). Após a cimentação, as amostras foram armazenadas em solução salina durante 7 dias e então submeti das à análise da força de retenção em máquina universal de ensaios (Zwick num. 112627, Ulm-Germany). Resultados: O cimento híbrido apresentou o maior valor médio de retenção (312.90 N), seguido do cimento de ionômero de vidro (272.40 N) e do cimento de fosfato de zinco (312.90 N). A análise estatística mostrou diferença estatisticamente significante nos valores de retenção entre o cimento de fosfato de zinco e o cimento de ionômero de vidro (p<0,01), e entre o cimento de fosfato de zinco e o cimento híbrido (p<0,01). Conclusão: Não houve discrepância significativa entre o cimento de ionômero de vidro e o cimento híbrido, embora a diferença na força de retenção entre os dois materiais tenha sido de aproximadamente 40 N.