Physicochemical properties, cytotoxicity and bioactivity of a ready-to-use bioceramic repair material

Abstract The aim of this study was to evaluate the physicochemical properties, cytotoxicity and bioactivity of a ready-to-use bioceramic material, Bio-C Repair (Angelus), in comparison with White MTA (Angelus) and Biodentine (Septodont). The physicochemical properties of setting time, radiopacity, pH, solubility, dimensional and volumetric changes were evaluated. Biocompatibility and bioactivity were assessed in Saos-2 osteoblast cell cultures by the MTT assay 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Neutral Red (NR), Alizarin Red (ARS), and cell migration tests. Statistical analysis was performed by ANOVA, Tukey or Bonferroni tests (α = 0.05). Bio-C Repair had the longest setting time (p < 0.05), but radiopacity and solubility were accordance with the ISO 6876/2012 standards, besides linear expansion. Bio-C Repair and MTA had similar volumetric change (p > 0.05); lower than Biodentine (p < 0.05). All the materials evaluated had an alkaline pH. Bio-C Repair was cytocompatible and promoted mineralized nodule deposition in 21 days and cell migration in 3 days. In conclusion, Bio-C Repair had adequate radiopacity above 3mm Al, solubility less than 3%, dimensional expansion, and low volumetric change. In addition, Bio-C Repair promoted an alkaline pH and presented bioactivity and biocompatibility similar to MTA and Biodentine, showing potential for use as a repair material.

Resumo O objetivo deste estudo foi avaliar as propriedades físico-químicas, citotoxicidade e bioatividade de um novo material biocerâmico pronto para uso, Bio-C Repair (Angelus), em comparação com MTA Branco (Angelus) e Biodentine (Septodont). Foram avaliadas as propriedades físico-químicas de tempo de presa, radiopacidade, pH, solubilidade, alterações dimensionais e volumétricas. A biocompatibilidade, bioatividade e capacidade de reparo foram avaliadas em culturas de células de osteoblastos Saos-2 pelo ensaio MTT brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio), vermelho neutro (NR), vermelho de alizarina ( ARS) e testes de migração celular. A análise estatística foi realizada pelos testes ANOVA, Tukey ou Bonferroni (α = 0,05). Bio-C Repair apresentou o maior tempo de presa (p < 0,05), mas radiopacidade e solubilidade de acordo com as normas ISO 6876/2012, além de expansão linear. Bio-C Repair e MTA tiveram variação volumétrica semelhante (p > 0,05), menor que Biodentine (p < 0,05). Todos os materiais avaliados apresentaram pH alcalino. Bio-C Repair foi citocompatível, além de promover deposição de nódulos mineralizados em 21 dias e migração celular em 3 dias. Em conclusão, o Bio-C Repair apresentou radiopacidade adequada acima de 3mmAl, solubilidade menor que 3%, expansão dimensional e baixa perda volumétrica.. Além disso, o Bio-C Repair promoveu um pH alcalino e apresentou bioatividade e biocompatibilidade semelhantes ao MTA e Biodentine, mostrando potencial para uso como material reparador

Effect of techniques, trays and materials on accuracy of impressions clinically made / Efeito de técnicas, moldeiras e materiais na exatidão de moldagens odontológicas

Abstract Introduction Making accurate and dimensionally stable impressions to duplicate oral conditions and tooth morphology is an essential step of prosthetic dentistry for fabricating well-fitted indirect restorations and, consequently, ensure the longevity and success of the treatment. Several authors describe pros and cons of different impression techniques, although there is no unanimity among them about the best one. Objective This study evaluated casts' accuracy made by different impression techniques, trays and materials. Material and method 10 patients were selected and 20 impressions from teeth #13 to #16 were performed using single-step (SS) and two-step techniques, made with metal stock and customized acrylic resin partial trays, vinyl polysiloxane and condensation silicone rubbers. Type IV gypsum was used to pour the casts. Three photographs of each patient (baseline), as their respective gypsum casts, were taken, measured in their interested buccal surface area. Comparisons of area values among experimental groups and baseline were performed. Data showed adherence to normal curve, being submitted to 3-way ANOVA/Bonferroni test (α=.05). Result Technique produced significant differences (P=0.02). SS technique was more accurate than BUR one (P=0.003; 95=1.22 to 5.98), but both resulted in similar casts to PVC, MOV and NR techniques, which were similar to each other (P>0.05). Conclusion SS technique showed the closest absolute values to baseline.

Resumo Introdução Realizar moldagens precisas e dimensionalmente estáveis que dupliquem a condição oral é um passo essencial para a confecção de restaurações indiretas de qualidade, garantindo seu sucesso e longevidade. Diversos estudos tem demonstrado os prós e contras de diferentes técnicas de moldagem, mas nenhum consenso da melhor técnica ainda foi descrito. Objetivo Este estudo avaliou a exatidão de modelos de gesso confeccionados por diferentes técnicas de moldagem, moldeiras e materiais. Material e método 10 pacientes foram selecionados e 20 moldes dos dentes #13 até #16 foram realizados utilizando técnicas simultânea (SS) e de dois passos, realizados com moldeiras parciais metálicas e individuais de resina acrílica, silicones de adição e condensação. Gesso tipo IV foi usados para os vazamentos. Três fotografias de cada paciente (baseline), assim como dos seus respectivos modelos de gesso foram realizadas e sua área foi então mensurada, na porção vestibular. Comparações de valores de área entre os grupos experimentais e o baseline foram performadas. Os dados mostraram aderência a curva normal, sendo submetidos ao teste 3-way ANOVA/Bonferroni (α=.05). Resultado As técnicas produziram diferenças significativas (P=0.02).Técnica simultânea foi mais precisa que a BUR (P=0.0003; 95=1,22 a 5.98), mas ambas resultaram em modelos similares àqueles feitos por meio das técnicas de PVC, MOV e sem NR, que foram similares entre si (P>0.05). Conclusão Técnica simultânea demonstrou valores absolutos similares àqueles demonstrados pelo baseline.

Comparison of impression techniques and double pouring by dental cast's accuracy. Preliminary clinical-lab trial

Aim: This study compared impression techniques and double pouring by means of cast's accuracy. Methods: For each patient (n=10), impressions from right maxillary canine to first molar were made with acrylic resin trays and vinyl-polysiloxane using one single-step, and four two-steps techniques: relief with poly(vinyl chloride) film; tungsten-carbide bur/scalpel blade; small movements of the tray; non-relief. Total visible buccal surface area of crowns was measured three times using photographs from patients (Baseline) and casts. Mean area values (mm2) between Baseline and casts differences were analyzed by two-way repeated-measures ANOVA (α=.05; 1-ß=85%). Results: No significant differences were observed for Impression Techniques (P=.525), Double Pouring (P=.281), and their interaction (P=.809). Conclusion: All impression techniques and double pouring produced casts with similar accuracy

Mandibular Reconstruction by Osteogenic Distraction Due to Two Different Injuries.

Varied factors, whether intrinsic or extrinsic, may lead to a decrease in the bone volume of the jaws. Trauma and pathology can be listed as examples of such factors. The aim of this study is to present the osteogenic distraction technique as alternative to augmentation of low mandibular bone volume caused by different etiologies. The first case reports a mandibular marginal resection of ameloblastoma and the second one reports a male patient presenting mandibular fracture sequelae. Both cases were treated according to the osteogenic distraction technique. Several factors have influence on the decision of treatment management of these conditions. Although autogenous bonegraft is considered criterion standard for alveolar reconstruction, its high rates of resorption and the morbidity associated to donor sites lead surgeons to seek for other surgical alternatives such as osteogenic distraction. Therefore, it also aims to expose the advantages and benefits of this technique as well as the satisfactory results achieved.

Deformation of nickel-titanium closed coil springs: an in vitro study.

OBJECTIVE: The aim of this paper was to determine the amount of deformation in four commercial brands of nickel-titanium closed springs. METHODS: A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, at 37 °C. Deactivation data were plotted and deformation was found graphically. The values were compared by analysis of variance and Tukey's post-hoc test. RESULTS: Springs manufactured by Morelli had the same amount of deformation when they were activated up to 700% of Y activation; springs by Orthometric had the same amount of deformation up to 600-700% of Y; springs by Ormco had the same amount of deformation up to 700-800% of Y; and finally, the majority of springs by GAC had similar deformation up to 800%-1000% of activation. All springs tested could be activated up to 700% without rupture. CONCLUSIONS: Most subgroups were similarly deformed up to 700% of activation, without rupture of springs. Subgroups 4B, 4C, 4D and 4E showed the same amount of deformation up to 1000% of activation without any rupture at all.

Deformation of nickel-titanium closed coil springs: an in vitro study

ABSTRACT Objective: The aim of this paper was to determine the amount of deformation in four commercial brands of nickel-titanium closed springs. Methods: A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, at 37 °C. Deactivation data were plotted and deformation was found graphically. The values were compared by analysis of variance and Tukey's post-hoc test. Results: Springs manufactured by Morelli had the same amount of deformation when they were activated up to 700% of Y activation; springs by Orthometric had the same amount of deformation up to 600-700% of Y; springs by Ormco had the same amount of deformation up to 700-800% of Y; and finally, the majority of springs by GAC had similar deformation up to 800%-1000% of activation. All springs tested could be activated up to 700% without rupture. Conclusions: Most subgroups were similarly deformed up to 700% of activation, without rupture of springs. Subgroups 4B, 4C, 4D and 4E showed the same amount of deformation up to 1000% of activation without any rupture at all.

RESUMO Objetivo: o objetivo desse trabalho foi determinar a deformação em molas fechadas de níquel-titânio de quatro marcas comerciais. Métodos: cento e trinta molas foram divididas em treze subgrupos, de acordo com suas características e fabricantes (Morelli, Orthometric, Ormco e GAC), com ativação entre 100% e 1.000% do comprimento efetivo de níquel-titânio presente na mola (Y), a 37 °C. Dados de desativação foram coletados e a deformação foi obtida de forma gráfica. Os valores foram comparados por meio de análise de variância e teste post-hoc de Tukey. Resultados: as molas da Morelli apresentaram a mesma quantidade de deformação considerando-se 700% de ativação de Y; as molas da Orthometric tiveram a mesma quantidade de deformação até 600-700% de Y; as molas da Ormco tiveram a mesma quantidade de deformação até 700-800% de Y; e, por fim, a maioria das molas da GAC apresentou deformação semelhante até 800-1.000% de ativação. Todas as molas testadas puderam ser ativadas até 700% sem ruptura. Conclusões: a maioria dos subgrupos se deformou de maneira semelhante até 700% de ativação, sem ruptura das molas. Os subgrupos 4B, 4C, 4D e 4E demonstraram a mesma quantidade de deformação até 1.000% de ativação, sem nenhuma ruptura.

Evaluation of Three Different Osteosynthesis Methods for Mandibular Angle Fractures: Vertical Load Test.

The aim of this study was to evaluate the mechanical behavior of different rigid fixation methods in mandible angle fractures. Three different plates were tested: one 4-hole grid miniplate, one 8-hole curved grid miniplate, and one 4-hole straight miniplate.For the loading tests, 30 polyurethane hemimandibles sectioned at the angle area to simulate a simple angle fracture were used: 10 hemimandibles for each group. The mechanical evaluation revealed that the straight plate positioned at the tension zone presented the best results in supporting vertical loading in the predefined displacement moments of 1, 3, and 5 mm. Regarding the grid plates, there was no statistically significant difference between the smaller and the larger plate.According to this sample, the straight plate positioned in the tension zone presented better results than the other 2 different grid plates positioned at the neutral zone.

Effect of Grinding and Resintering on the Fatigue Limit and Surface Characterization of a Y-TZP Ceramic

Abstract This study evaluated the effect of grinding protocols and resintering on flexural fatigue limit and surface characterization of LavaTM Y-TZP. Bar-shaped specimens (20×4.0×1.2 mm, n=40; 20×4.0×1.5 mm, n=80) were obtained. Half of the thinner specimens (1.2 mm) constituted the as-sintered group (AS), while the thicker ones (1.5 mm) were ground with diamond burs under irrigation (WG) or not (G). The other half of thinner and half of ground specimens were resintered (1000 ºC, 30 min), forming the groups ASR, WGR and GR. Fatigue limit (500,000 cycles, 10 Hz) was evaluated by staircase method in a 4-point flexural fixture. Data were analyzed by 2-way ANOVA and Tukey's test (α=0.05). Surface topography (n=3) and fracture area (n=3) were evaluated by SEM. X-ray diffraction data (n=1) was analyzed by Rietveld refinement. ANOVA revealed significant differences (p<0.001) for the grinding protocol, resintering and their interaction. Grinding increased the fatigue limit of non-resintered groups. There was no significant difference among the resintered groups. Resintering significantly increased the fatigue limit of the AS group only. Both protocols created evident grooves on zirconia surface. The failures initiated at the tensile side of all specimens. The percentages (wt%) of monoclinic phase were AS (8.6), ASR (1.2), G (1.8), GR (0.0), WG (8.2), WGR (0.0) before, and AS (7.4), ASR (6.5), G (3.2), GR (0.2), WG (4.6), WGR (1.1) after cyclic loading. Grinding increased the fatigue limit of non-resintered Y-TZP and formed evident grooves on its surface. Resintering provided significant increase in the fatigue limit of as-sintered specimens. In general, grinding and resintering decreased or zeroed the monoclinic phase.

Resumo Este estudo avaliou o efeito de protocolos de desgaste e ressinterização no limite de fadiga flexural e na caracterização da superfície da zircônia LavaTM. Corpos-de-prova em forma de barra (20×4,0×1,2 mm, n=40; 20×4,0×1,5 mm, n=80) foram obtidos. Metade das barras com menor altura (1,2 mm) constituiu o grupo controle (AS), enquanto as de maior altura (1,5 mm) foram desgastadas com fresas diamantadas com (WG) ou sem (G) irrigação. A outra metade dos corpos-de-prova de menor altura e metade dos desgastados foram ressinterizadas (1000 °C, 30 min), obtendo-se os grupos ASR, WGR e GR. O limite de fadiga (500.000 ciclos, 10 Hz) foi avaliado pelo método de escada em dispositivo de flexão em 4 pontos. Os dados foram analisados pelos testes ANOVA a dois fatores e Tukey (α=0,05). A topografia de superfície (n=3) e área de fratura (n=3) foram avaliadas por MEV. Os dados de difração de raios-X (n=1) foram analisados pelo refinamento de Rietveld. ANOVA revelou diferenças significantes (p<0,001) para desgaste, ressinterização e interação entre os fatores. O desgaste aumentou o limite de fadiga para os grupos não ressinterizados. Não houve diferença significante entre os grupos ressinterizados. A ressinterização aumentou o limite de fadiga somente para o grupo AS. Ambos os protocolos criaram riscos evidentes na superfície da zircônia. As falhas iniciaram sempre no lado de tração. A porcentagem de fase monoclínica foi: AS (8.6), ASR (1.2), G (1.8), GR (0.0), WG (8.2), WGR (0.0) antes e AS (7.4), ASR (6.5), G (3.2), GR (0.2), WG (4.6), WGR (1.1) após a ciclagem. O desgaste aumentou o limite de fadiga da zircônia não ressinterizada e formou ranhuras evidentes na sua superfície. A ressinterização promoveu aumento significativo no limite de fadiga somente para o grupo controle. Em geral, o desgaste e a ressinterização diminuíram ou anularam o conteúdo de fase monoclínica.

Influence of Sealing of the Screw Access Hole on the Fracture Resistance of Implant-Supported Restorations

Abstract The purpose of this study was to assess the influence of sealing of the screw access hole (SAH) on the fracture resistance of metal-ceramic implant-supported restorations. UCLA abutments were used to make 30 implant-retained mandibular molar restorations and divide equally into three groups: Group SRS: screw-retained restorations with SAH sealed; Group SRNS: screw-retained restorations with SAH not sealed; Group CR: cement-retained restorations. The following protocol was adopted to restore the SAH: the ceramic surface of the SAH was air-abraded with aluminum oxide; etched with 10% hydrofluoric acid; a silane coupling agent and a bonding agent were applied; cotton pellets were used as filling material and P-60 resin composite as restoring material. The cement-retained restorations were cemented with Rely-X U100. A metal rod with a spherical tip of 6.0 mm diameter was used to apply a vertical static load, simultaneously on the buccal and lingual incline cusps, at a crosshead speed of 0.5 mm/min until the fracture of the specimens. Data were analyzed using one-way ANOVA and Dunnet test (p<0.05) for multiples comparisons. The mode of failure was evaluated by a scanning electron microscopy (SEM). No significant difference between screw-retained restorations was found. The highest mean fracture resistance values were observed with CR group. Therefore, it was shown that SAH sealing did not influence the fracture resistance of the screw-retained restorations.

Resumo O objetivo deste estudo foi avaliar a influência do selamento do orifício de acesso ao parafuso (OAP) na resistência à fratura de coroas metalocerâmicas implantossuportadas aparafusadas. Pilares UCLA foram utilizados para fazer 30 molares inferiores implantossuportados e divididos igualmente em três grupos: Grupo AS: coroas aparafusadas com o OAP selado; Grupo ANS: coroas aparafusadas com o OAP não selado; Grupo CC: coroas cimentadas. O seguinte protocolo foi utilizado para selar o OAP: a superfície de cerâmica do OAP foi jateada com óxido de alumínio; condicionada com ácido fluorídrico a 10%; um agente silano e um adesivo dentinário foram aplicados; bolinhas de algodão foram utilizadas como material de preenchimento e a resina composta P-60 como material de restauração. As coroas cimentadas foram cimentadas com Rely-X U100. Uma haste de metal com uma ponta esférica de 6.0 mm de diâmetro foi usada para aplicar uma carga estática vertical, simultaneamente nas vertentes triturantes das cúspides linguais e vestibulares, com 0,5 mm/min velocidade do atuador até a fratura das coroas. Os dados foram analisados através de ANOVA um fator e teste de Dunnett (p<0,05) para as comparações múltiplas. O modo de falha foi avaliado por um microscópio eletrônico de varredura (MEV). Não houve diferença significativa entre restaurações aparafusadas. Os maiores valores médios de resistência à fratura foram observados com o Grupo CC. Portanto, observou-se que o selamento do OAP não influenciou a resistência à fratura das coroas aparafusadas.

Sistema Cone Morse e utilização de pilares com plataforma switching / Morse Taper System and platform switching abutment application

Os implantes cone morse associados a pilares com plataforma switching têm proporcionado resultados promissores com relação à estabilidade dos tecidos peri-implantares. Isso se deve ao perfil cônico do componente protético, à íntima adaptação na interface implante/pilar e ao menor acúmulo de biofilme bacteriano. Para isso, deve-se levar em consideração o posicionamento infraósseo do implante. Essa configuração implante/pilar possui resistência à fratura superior em relação aos sistemas convencionais e, além disso, devido à manutenção da crista óssea e da diversidade de pilares e componentes protéticos, possibilita reabilitações orais estéticas e biocompatíveis.

Morse taper implants associated with platform switching abutments have provided promising results with respect to the stability of peri-implant tissues. This is due to the conical profile of the abutment, the intimate adaptation at the implant/abutment interface, and to the lower accumulation of bacterial biofilm. For this, it has been proposed the insertion of the implants below the crestal bone level. This implant/ abutment configuration presents higher fracture strength compared to the conventional systems and, in addition, because of the maintenance of crestal bone and the diversity of abutments and prosthetic components, provides aesthetic and biocompatible oral rehabilitations.

Fracture Resistance of Simulated Immature Teeth after Different Intra-radicular Treatments

The aim of this study was to evaluate the fracture resistance of simulated immature teeth after different intra-radicular treatments. Crowns and roots of bovine incisors were cut transversally and removed to simulate immature teeth. Root canal preparation and flaring were performed using a bur in crown-apex and apex-crown direction. The samples were distributed into 5 groups (n=10): Positive control (PoC) - no root canal flaring or filling; Negative control (NeC) - teeth were sectioned and their root canals were flared; Direct anatomical glass fiber post (RaP) - #2 Reforpost main glass fiber post relined with composite resin; Double tapered conical glass fiber posts (ExP) - #3 Exacto glass fiber post; and #2 Reforpost main glass fiber + Reforpin accessory glass fiber posts (RrP). In RaP, ExP and RrP, 4.0-mm apical plugs were done with MTA Angelus. The specimens were embedded in polystyrene resin inside cylinders and the periodontal ligament was simulated with a polyether-based impression material. The specimens were submitted to compressive fracture strength test (0.5 mm/min at 135° relative to the long axis of the tooth) in a servo-hydraulic mechanical testing machine MTS 810. Data were subjected to one-way ANOVA and Dunnett's C or Tukey's tests (α=0.05). The control groups (PoC and NeC) showed lower fracture strength than the experimental groups. NeC presented the lowest resistance and ExP presented the highest resistance among the experimental groups. The flaring procedures produced a detrimental effect on the fracture resistance of the bovine teeth. Glass fiber intra-radicular posts increased significantly the fracture resistance of simulated immature teeth.

O objetivo deste estudo foi avaliar a resistência à fratura de dentes com rizogênese incompleta simulada após diferentes tratamentos intra-radiculares. A rizogênese incompleta foi simulada pelo seccionamento das coroas e raízes de incisivos bovinos. O preparo e alargamento do canal radicular foram realizados utilizando uma broca no sentido coroa-ápice e ápice-coroa. As amostras foram distribuídas (n=10) em cinco grupos: controle positivo (PoC) - sem preparo do canal radicular e sem obturação; controle negativo (NeC) - os dentes foram seccionados e os canais radiculares foram preparados; pino anatômico direto Reforpost #2 (RaP) - pino de fibra de vidro principal + resina composta; pino de fibra de vidro com dupla conicidade (ExP) - pino de fibra de vidro Exacto #3; e pino de fibra de vidro Reforpost #2 + pinos de fibra de vidro acessórios Reforpin (RrP). Nos grupos RaP, ExP e RrP foram realizados plugs apicais de MTA Angelus com 4,0 mm. As amostras foram incluídas em cilindros com resina de poliestireno e o ligamento periodontal foi simulado com material de moldagem à base de poliéter. As amostras foram submetidas ao teste de resistência à fratura, por meio de força compressiva (0,5 mm/min a 135º em relação ao longo eixo do dente) em uma máquina de ensaios mecânicos MTS 810. Os dados foram submetidos à ANOVA a um critério e aos testes para comparações múltiplas Dunnett C ou Tukey HSD (α=0,05). Os grupos controle (PoC e NeC) apresentaram resistência à fratura inferior aos grupos experimentais, sendo o menor valor médio produzido por NeC. ExP produziu os maiores valores de resistência à fratura entre os grupos experimentais. Os procedimentos de preparo e alargamento produziram efeitos prejudiciais na resistência à fratura de dentes bovinos. A utilização de pinos de fibra de vidro intra-radiculares aumentou significativamente a resistência à fratura de dentes com rizogênese incompleta simulada.

Periapical repair following endodontic surgery: two- and three-dimensional imaging evaluation methods.

This study quantitatively assessed the periapical bone repair following endodontic surgery, using planimetric evaluation based on two- (conventional and digital intraoral radiographic images - IRs) and three-dimensional (cone beam computed tomography - CBCT) evaluation. Eleven maxillary anterior teeth (of 11 patients) with periapical bone lesions and indication for surgical endodontic treatment were selected. IRs and CBCT images were acquired before the endodontic surgery, and 48 h, 4, and 8-months after the surgery. In each period of evaluation, the area (mm2) of the bone lesion was measured in the images, and the values for the three methods were compared. The area in the CBCT images was measured in the mesio-distal sections comprising the largest diameter of the lesion. Data were submitted to repeated measures 2-way ANOVA and t-tests with Bonferroni correction. There was significant difference between the periods of evaluation (p=0.002) regarding the assessed periapical bone lesion area. There was no statistically significant difference between the methods of evaluation (p=0.023). In the CBCT images the lesion areas were 10% larger than those observed in the conventional IRs (22.84 mm2) and 15% larger than those observed in the digital IRs (21.48 mm2). From the baseline (40.12 mm2) to 4 (20.06 mm2) and 8-months (9.40 mm2), reductions of 50 and 77% in the lesion area, respectively, were observed (p<0.0001). From 4 to 8-months, this value was 53%. Progressive bone repair could be seen from 48 h to 8-months following endodontic surgery based on two- (conventional and digital IRs) and three-dimensional (CBCT) evaluation. CBCT images provided results similar to those assessed by means of IRs.

Periapical Repair Following Endodontic Surgery: Two- and Three-Dimensional Imaging Evaluation Methods

This study quantitatively assessed the periapical bone repair following endodontic surgery, using planimetric evaluation based on two- (conventional and digital intraoral radiographic images - IRs) and three-dimensional (cone beam computed tomography - CBCT) evaluation. Eleven maxillary anterior teeth (of 11 patients) with periapical bone lesions and indication for surgical endodontic treatment were selected. IRs and CBCT images were acquired before the endodontic surgery, and 48 h, 4, and 8-months after the surgery. In each period of evaluation, the area (mm2) of the bone lesion was measured in the images, and the values for the three methods were compared. The area in the CBCT images was measured in the mesio-distal sections comprising the largest diameter of the lesion. Data were submitted to repeated measures 2-way ANOVA and t-tests with Bonferroni correction. There was significant difference between the periods of evaluation (p=0.002) regarding the assessed periapical bone lesion area. There was no statistically significant difference between the methods of evaluation (p=0.023). In the CBCT images the lesion areas were 10% larger than those observed in the conventional IRs (22.84 mm2) and 15% larger than those observed in the digital IRs (21.48 mm2). From the baseline (40.12 mm2) to 4 (20.06 mm2) and 8-months (9.40 mm2), reductions of 50 and 77% in the lesion area, respectively, were observed (p<0.0001). From 4 to 8-months, this value was 53%. Progressive bone repair could be seen from 48h to 8-months following endodontic surgery based on two- (conventional and digital IRs) and three-dimensional (CBCT) evaluation. CBCT images provided results similar to those assessed by means of IRs.

Este estudo avaliou quantitativamente a reparação óssea periapical após cirurgia parendodôntica, utilizando avaliação planimétrica bidimensional (imagens convencionais e digitais intraorais radiográficas-IRs) e tridimensional (CBCT). Onze dentes anteriores da maxila (de 11 pacientes) com lesões ósseas periapicais e indicação de tratamento endodôntico cirúrgico foram selecionados. IRs e imagens tomográficas foram obtidas antes da cirurgia parendodôntica, e 48 h, 4 e 8 meses após a cirurgia. Para cada período, a área (mm2) de rarefação óssea foi mensurada, e os valores para os três métodos comparados. A área nas imagens de CBCT foi mensurada nas seções mésio-distal, compreendendo o maior diâmetro da lesão. Os dados foram submetidos à análise de variância de medidas repetidas a dois critérios e teste T com correção de Bonferroni. Houve diferença significativa entre os períodos de avaliação (p=0,002) em relação à área de lesão óssea periapical mensurada. Não houve diferença significativa entre os métodos de avaliação (p=0,023). Nas imagens tomográficas as áreas das lesões foram 10% maiores do que as observados nas IRs convencionais (22,84 mm2) e 15% maior do que àquelas das digitais (21,48 mm2). A partir dos valores baseline (40,12 mm2) a 4 (20,06 mm2) e 8 meses (9,40 mm2), foram observadas reduções de 50 e 77%, respectivamente, na área das lesões (p<0,0001). De 4 a 8 meses, esse valor foi de 53%. Entre o período de 48h a oito meses após as cirurgias parendodônticas foram observadas reparações ósseas progressivas nas avaliações bidimensionais (IRs convencional e digital) e tridimensional (CBCT). A CBCT produziu resultados semelhantes aqueles avaliados por meio das IRs.

Surface roughness and hardness of yttria stabilized zirconia (Y-TZP) after 10 years of simulated brushing / Avaliação da rugosidade e dureza da zircônia Y-TZP após simulação de 10 anos de escovação

Introduction: The Y-TZP zirconia used for prosthetic infrastructure, in some clinical situations, can be exposed to the oral environment. In these situations, a polished surface without changes is extremely important. Objective: The aim of this study was to evaluate the mean roughness (Ra) and Vickers hardness of Y-TZP zirconia (LavaTM) after simulating ten years of brushing. Material and method: Thirty-six Y-TZP bar-shaped specimens (20mm X 4mm X 1.2mm) were divided into three groups: storage in distilled water (DW, n=12, control); brushing with distilled water (BDW, n=12) and brushing with distilled water and fluoride toothpaste (BFT, n=12). Brushing was performed using a brushing machine with a soft-bristled toothbrush, simulating 10 years of brushing (878.400 cycles, 100gf). The mean roughness (Ra in µm)) and Vickers hardness (VHN) of all specimens were measured twice: before and after the experimental treatment, in profilometer and microhardness tester (500gf, 30 seconds), respectively. Data were analyzed using the two-way ANOVA test (α = 0.05). Result: The interaction between groups was not significant for roughness (p = 0.701) nor for hardness (p = 0.928). The final averages for Ra (μm) were equal to: DW - 0.63; BDW - 0.64; and, BFT - 0.68. The final averages for Vickers hardness (VHN) were: DW - 1301.16; BDW - 1316.60; and, BFT - 1299.58. Conclusion: It was concluded that the brushing with distilled or fluoridated toothpaste was not able to change the roughness and hardness of Y-TZP zirconia used in this study. .

Introdução: A zircônia estabilizada por ítria (Y-TZP) utilizada para infraestruturas protéticas pode, em algumas situações clínicas, ficar exposta ao meio bucal, e nessas situações, uma superfície sem alterações e polida é extremamente importante. Objetivo: Assim, este estudo avaliou a rugosidade média (Ra) e a dureza Vickers da zircônia LavaTM após simulação de dez anos de escovação. Material e método: Foram confeccionados 36 espécimes (20mm X 4mm X 1,2mm), divididos em três grupos: armazenamento em água destilada (AD, n=12, controle), escovação com água destilada (EAD, n=12) e escovação com água destilada e dentifrício fluoretado (EDF, n=12). A escovação foi realizada em máquina de escovação simulando 10 anos (878.400 ciclos, lOOgf) com escova dental macia. A rugosidade média (Ra, em µm) e a dureza Vickers (VHN) de todos os corpos-de-prova foram mensuradas em dois momentos: antes e após o tratamento experimental, em rugosímetro e microdurômetro (500gf, 30 segundos), respectivamente. Os dados foram analisados por meio do teste two-way ANOVA (α=0,05). Resultado: A interação entre os grupos não foi significativa tanto para a rugosidade (p=0,701) quanto para a dureza (p=0,928), sendo as médias finais de Ra (µm) iguais a: AD - 0,63; EAD - 0,64 e EDF - 0,68 e as de dureza Vickers (VHN) iguais a: AD - 1301,16; EAD - 1316,60 e EDF - 1299,58. Conclusão: Concluiu-se que o procedimento de escovação com água destilada ou com dentifrício fluoretado não foi capaz de alterar a rugosidade e a dureza da zircônia Y-TZP utilizada neste estudo. .

Photoelasticity in Dentistry: a literature review

Introduction and Objective: Photoelasticity consists of an experimental technique of stress analysis. This technique is very used in most different areas including Dentistry. This literature review presents the several applications of photoelastic technique in Dentistry as well as its advantages and disadvantages. Literature review: Based on this method of analysis, it is possible the verification of the stress distribution and deformation in structures with complex geometry as maxilla and mandible. It can be used to evaluate the distribution of stress on several types of prosthesis as removable partial denture systems with different retention systems, conventional implant prosthesis, overdentures and Brånemark protocols. Moreover, photoelasticity can be used to assess the stress generated by various orthodontic movements, different orthodontic systems and different materials (orthodontic wires). In addition, it is used to analyze different defects of maxillectomy, splint types on traumatized tooth and post-core restoration methods. This technique can also be used to assess dental instruments such as evaluation of different designs of periodontal probe. Conclusion: The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible.

Resina composta indireta como alternativa funcional eestética em reabilitações protéticas / Indirect composite resin as functional and aesthetic alternative in dental prosthesis

Devido à melhoria nas propriedades das resinascompostas indiretas, principalmente quandoassociadas com fibras de reforço, esse materialtornou-se mais uma alternativa para os procedimentosreabilitadores. Um paciente, 57 anos,compareceu à Clínica de Prótese da Faculdadede Odontologia de Araraquara, queixando-seda ausência do primeiro molar superior direito.Após exame clínico, verificou-se diminuiçãono periodonto de suporte do segundo molarsuperior direito, restaurado com amálgama esegundo pré-molar superior direito reabilitadoinsatisfatoriamente. De acordo com as condiçõesclínicas e os anseios estéticos do paciente,foi confeccionada uma prótese parcial fixa de 3elementos, utilizando resina composta indiretacom fibras de reforço. O paciente demonstrouseplenamente satisfeito com o resultado estéticoe funcional obtido. O caso encontra-se emproservação há 60 meses.

Due to mechanical and aesthetic improvementproperties, continuous fiber-reinforcedcomposites have been developed to replacethe metal framework in fixed partial denturesbecoming an interesting alternative toconventional treatments. A male patient, 57years old, attended at Fixed Partial DentureClinic of Araraquara Dental School - UNESP,complaining about upper right first molar absence.After clinical examination, it was observed:upper right second molar with amalgamrestoration and periodontal bone reductionand upper right second premolar unsatisfactorytreated. Following the clinical conditionsand the patient expectations, it was decidedto use a fiber-reinforced composite resin tomake a three-element fixed bridge. The patientshowed full satisfaction with the aestheticand functional results. The case has beenfollowed up for 60 months.

Previsibilidade de implantes curtos: revisão de literatura / Predictability of short dental implants: a literature review

Introdução: Nas situações clínicas em que ocorre severa reabsorção óssea após perda de dentes, as opções de tratamento com implantes incluem a necessidade de reconstrução óssea prévia e instalação de implantes convencionais ou apenas de implantes curtos. Objetivo: Revisar não sistematicamente a literatura com o propósito de sintetizar e discutir alguns itens sobre o uso de implantes curtos, tais como aspectos biomecânicos, índices de sucesso, longevidade e planejamento cirúrgico-protético. Revisão de literatura: Buscou-se selecionar referências atuais e de impacto acerca dos implantes curtos, comparando-os aos convencionais. Diversos estudos destacam a maior importância do diâmetro dos implantes. Para a prática clínica os curtos apresentam altas taxas de sucesso e previsibilidade quando determinados aspectos biomecânicos são levados em consideração. Conclusão: A colocação de implantes curtos torna-se um tratamento viável para pacientes com altura óssea reduzida.

Introduction: In clinical situations where severe bone resorption has occurred following tooth loss, implant treatment options may comprise either a previous bone reconstruction or only the use of short implants. Objective: This non-systematic review summarizes and discusses some aspects of the use of short implants, such as: biomechanical aspects, success rate, longevity and surgical-prosthetic planning. Literature review: Current and relevant references were selected in order to compare short dental implants to conventional ones. Several studies have highlighted the great importance of wide-diameter implants. Dental short implants have shown high predictability and success rates when some biomechanical aspects are taken into consideration. Conclusion: Placement of short dental implants is a viable treatment method for patients with decreased bone height.

Associação entre implantes odontológicos e próteses parciais removíveis: revisão de literatura / Association between implants and removable partial dentures: review of the literature

Introdução: A prótese parcial removível de extremidade livre unilateral ou bilateral apresenta complexa biomecânica. Seus movimentos em diversas direções, juntamente com a forma do rebordo alveolar e a resiliência da fibromucosa, podem levar a forças danosas sobre as estruturas de suporte. A associação entre implantes e prótese parcial removível visa proporcionar melhores propriedades mecânico-biológicas ao sistema estomatognático. Objetivo: Realizar uma revisão de literatura e discussão quanto ao uso dessa alternativa de reabilitação. Revisão de literatura e conclusão: Estudos têm evidenciado que essa associação oferece maior suporte, retenção e estabilidade às próteses, limitando seu movimento de aproximação em direção aos tecidos de suporte e propiciando conforto funcional e psicológico aos pacientes.

Introduction: Unilateral or bilateral distal-extension removable partial dentures present complex biomechanics. The movements in different directions, associated with the alveolar ridge shape and soft tissue resilience can lead to damaging forces on the supporting structures. The association between implants / removable partial denture aims to provide better mechanical and biological properties to the stomatognathic system. Objective: The aim of this paper was to review the articles about the effect of implant support on distal extension removable partial dentures. Literature review and conclusion: Studies have shown that this combination provides greater support, retention and stability to the prosthesis, thus limiting their approach movement toward supporting tissues and providing functional and psychological comfort to patients.

Implantes curtos / Short implants - review

O avanço tecnológico na Implantodontia contemporânea tem facilitado o processo de reabilitação oral dos pacientes parcialmente ou totalmente edêntulos. Por outro lado, acidentes anatômicos, como a presença do seio maxilar e do canal mandibular na região posterior dos maxilares, limitam a colocação de implantes nessas regiões. Além disso, devido à ausência dentária, frequentemente, se observa a atrofia dos rebordos maxilares e mandibulares, o que limita o tecido ósseo disponível para a reabilitação dos pacientes com próteses sobreimplantes osseointegráveis. Algumas soluções vêm sendo realizadas a fim de possibilitar a reabilitação com implantes odontológicos em situações adversas, como a utilização de implantes curtos (até 10 mm) e/ou implantes de menor diâmetro (2,8; 3,3 e 3,5 mm). O objetivo deste estudo foi revisar a literatura sobre a utilização de implantes odontológicos curtos, trazendo para o clínico uma visão atual sobre o tema. Com base na literatura atual, conclui-se que os implantes odontológicos curtos apresentam taxa de sucesso clínico semelhante àquela dos implantes convencionais, sendo uma alternativa viável para os procedimentos reabilitadores em situações limítrofes.