Fracture strength and failure load of CAD/CAM fabricated endocrowns performed with different designs

Aim: Endocrown restorations are commonly used to rehabilitate endodontically treated posterior teeth and their use is well-founded in these cases. However, to date, there is little scientific evidence of their behavior in anterior teeth. The aim of this in vitro study was to evaluate the compressive strength of upper central incisors teeth, restored with glass-ceramic total crowns by the conventional anatomical core technique, and compare them to teeth restored with endocrowns with and without the presence of ferrule. Methods: Thirty teeth were randomly distributed into three groups: GE2 - endocrown group with 2 mm ferrule, GE0 - endocrown group without a ferrule, and GC - conventional crown with intraradicular post group. Crowns were cemented and teeth submitted to the 45o compression test until the fracture happened. Fractured specimens were analyzed to determine the fracture pattern. Descriptive analysis of the variables was performed and one-way analysis of variance was utilized to analyze the data for significant differences at p < 0.05. Results: The results of the control group (284.5 ± 201.05N) showed the highest fracture resistance value, followed by the 2mm group (274.54 ± 199.43N) and by the 0mm group (263.81 ± 80.05N). There was no statistically significant difference between all the groups (p = 0.964). Conclusions: The absence of a cervical enamel necklace favored a debonding of the pieces and endodontically treated anterior teeth could be restored with endocrown, which could be considered a conservative and viable treatment option

Clustering profiles of demographic and clinical characteristics and the oral health impact of individuals with temporomandibular disorders.

OBJECTIVE: To identify profiles of demographic, clinical, and oral health impact characteristics of individuals with temporomandibular disorder (TMD). METHODS: Four hundred ninety-six TMD patients (260 females) and 30 young controls were included. Sociodemographic, clinical, and Oral Health Impact Profile (OHIP-14) data were gathered and analyzed by Cluster, ANOVA, and regression analyses. RESULTS: Three clusters were identified: "Pain and depression symptoms" with participants with higher pain, depression, and OHIP-14 scores (59% females); "Chronic diseases" included older participants with current chronic diseases and medical treatment; "Healthier individuals" included younger individuals with lower chronic diseases, pain, and depression frequencies, whose OHIP-14 scores did not differ from controls (p = 0.079). OHIP-14 scores were predicted by age, pain, and depression. CONCLUSION: Distinct profiles of individuals with TMD were identified, emphasizing the complex interactions between coping ability, general health, and psychosocial aspects that must be monitored.

Number of dental abutments influencing the biomechanical behavior of tooth‒implant-supported fixed partial dentures: A finite element analysis.

Background. Local or systemic issues might prevent installing a sufficient number of dental implants for fixed prosthetic rehabilitation. Splinting dental implants and natural teeth in fixed dentures could overcome such limitations. Therefore, this study aimed to evaluate the influence of the number of dental abutments in the biomechanics of tooth‒implant-supported fixed partial dentures (FPDs). The null hypothesis was that increasing the number of abutment teeth would not decrease the stress over the abutments and surrounding bone. Methods. Left mandibular lateral incisor, canine, premolars, and molars were reconstructed through computed tomography and edited using image processing software to represent a cemented fixed metal‒ceramic partial denture. Three models were set to reduce the number of abutment teeth: 1) lateral incisor, canine, and first premolar; 2) canine and first premolar; 3) the first premolar. The second premolar and first molar were set as pontics, and the second molar was set as an implant abutment in all the models. Finite element analyses were performed under physiologic masticatory forces with axial and oblique loading vectors. Results. After simulation of axial loads, the stress peaks on the bone around the implant, the bone around the first premolar, and prosthetic structures did not exhibit significant changes when the number of abutment teeth decreased. However, under oblique loads, decreasing the number of abutment teeth increased stress peaks on the surrounding bone and denture. Conclusion. Increasing the number of dental abutments in tooth‒implant-supported cemented FPD models decreased stresses on its constituents, favoring the prosthetic biomechanics.

Fracture Resistance of CAD/CAM Lithium Disilicate of Endodontically Treated Mandibular Damaged Molars Based on Different Preparation Designs.

The aim of this study was to evaluate the fracture resistance of 2 different types of all-ceramic crown using immediate dentin sealing (IDS), obtained using a CAD/CAM system on molars with different preparations. Forty extracted lower molars were endodontically treated and divided into four groups (n = 10) according to the dental preparation. Group 1 (SP0) was prepared without filling the pulp chamber and crown-root junction was located at the cementoenamel junction (CEJ). Group 2 (SP1) was prepared without filling the pulp chamber and crown-root junction was located 1-mm above the CEJ. Groups 3 and 4 contained a flat preparation surface with no axial wall height. Group 3 (CP0) was made IDS with complete filling of the pulp chamber with composite resin and crown-root junction was located at the CEJ. Group 4 (CP1) was prepared with complete filling of the pulp chamber and crown-root junction was located 1-mm above the CEJ. All groups were restored with CAD/CAM lithium disilicate ceramic crowns. Specimens were subjected to the fracture test and statistically analyzed using analysis of variance (ANOVA). Fracture mode was determined using a stereoscopic microscope, classified as repairable or nonrepairable, and analyzed using Fischer's exact test. Results indicated that there were no significant differences between the groups in terms of fracture resistance or fracture pattern (p >0.05). Fracture resistance was the lowest in the SP0 group, followed by the SP1 group (1634.38 N) of CP0 (1821.50 N), and it was the highest in the CP1 group. There was a predominance of nonrepairable fractures and there were no significant differences in the fracture resistance and fracture mode of CAD/CAM lithium disilicate molar all-ceramic crowns. Endodontically treated molars teeth might be restored with endocrowns or all-ceramic crowns on flat preparation; however tooth fracture failures that affect reliability of these types of restorations should be considered.

Effects of the combination of Er: YAG laser and sandblasting on the shear bond strength between zirconia and resin cement

Aim: This study was conducted to determine the bond strength between zirconia ceramic and resin luting cement according to the type of surface treatment applied. Methods: Sixty zirconia cylinders measuring 4 x 4 mm were manufactured and distributed into five experimental groups and a control group (n = 10): G1 - sandblasting with 110 µm aluminum oxide; G2 - sandblasting with 30 µm Rocatec Soft®; G3 - Er:YAG laser irradiation at 400 mJ; G4 - Er:YAG laser combined with sandblasting with aluminum oxide; G5 - Er:YAG laser combined with sandblasting with Rocatec Soft®; G6 - no treatment (Control). The zirconia cylinders were bonded in the center of composite resin cylinders (6 mm diameter) using RelyX Ultimate® cement. Shear strength was measured after thermocycling (6000 cycles and 5-55° C). Data were analyzed using one-way ANOVA and Tukey's post-hoc with a 5% significance level. Results: Group 4 had a significantly higher shear strength than all the other groups, except Group 1. Group 3 had a significantly lower shear strength compared with Groups 1 and 4. Conclusion: Sandblasting with 110µm aluminum oxide particles after laser irradiation may be an effective zirconia surface treatment. The use of Er: YAG laser alone is not effective at increasing the bond between resin cement and zirconia

Influence of Nd:YAG laser on the penetration of a bioceramic root canal sealer into dentinal tubules: A confocal analysis.

OBJECTIVE: The aim of this in vitro study, is to evaluate the penetration of a bioceramic root canal sealer into dentinal tubules at 3 mm and 5 mm from the apex after Nd:YAG laser irradiation. METHODS: Forty freshly extracted human mandibular premolars were prepared using Reciproc® and irrigated with 17% ethylenediaminetetraacetic acid (EDTA). Teeth were divided into 4 groups: group 1, obturated with control sealer (AH Plus®); group 2, obturated with bioceramic sealer (Endosequence BC Sealer®); group 3, Nd:YAG laser + control sealer (AH Plus®); and group 4, Nd:YAG laser + bioceramic sealer (Endosequence BC Sealer®). The samples were transversely sectioned 3 mm and 5 mm from the apex and examined using confocal laser scanning microscopy. Two parameters were measured: 1) sealer penetration into dentinal tubules of the root canal and 2) sealer penetration into the perimeter of the root canal walls. RESULTS: Penetration analysis showed that bioceramic sealer had a higher penetration at depths of 3 and 5 mm than that of the control sealer, regardless of laser use (p <0.05). Perimeter analysis showed that there was no difference between both sealers at a depth of 3 mm (p <0.05), regardless of laser use. At a depth of 5 mm, bioceramic sealer and laser showed a greater perimeter of penetration (p <0.05) than the control sealer. CONCLUSION: The use of Nd:YAG laser did not compromise the penetration of bioceramic sealer into dentinal tubules of root canals at 3 mm and 5 mm from the apex.

Influence of temporomandibular joint dysfunction on the development of the masseter muscle standard thickness / Influência da disfunção temporomandibular no padrão de desenvolvimento da espessura do músculo masseter

Objective: To evaluate the occurrence of alterations in the thickness of Masseter, through non-invasive technique of image ultrasonography, in subjects with temporomandibular joint disorder. Methods: The thickness of Masseter muscle was measured by bilateral, transverse sections, in real time, through image ultrasonography, in thirty-five volunteers, from 19 to 45 years, who were classified in two groups: Group A - symptomatic patients (21 volunteers - 10 men and 11 women), and Group B - asymptomatic patients (14 volunteers - 7 of each gender). Results: The results were submitted to the test t of Student for independent samples (p? 0.05). The masculine Masseter measured were shown to be bigger than the feminine ones in both the groups. Among the participants of the Groups A and B, the width and length of the Masseter muscles, left and right, are, on average, 23% and 12%, respectively, bigger in men. However, no differences were found in the thickness of this muscle between the subjects with or without temporomandibular disorders.Conclusion: The measurement of the Masseter muscle thickness, by Ultrasonography images, is not conclusive for temporomandibular disorders (TMD).

Objetivo: Avaliar a ocorrência de alterações na espessura do músculo Masseter, por técnica não invasiva de ultrassonografia de imagem, em portadores de disfunção temporomandibular. Métodos: A espessura do músculo Masseter foi mensurada em cortes transversais, bilaterais e, em tempo real, por meio da técnica ultrassonográfica de imagem, em trinta e cinco voluntários, com idades entre dezenove e quarenta anos, que foram classificados em dois grupos: Grupo A - portadores de disfunção temporomandibular sintomáticos (21 voluntários, sendo 10 homens e 11 mulheres), e Grupo B - assintomático (14 voluntários, sendo 7 de cada sexo). Resultados: Os resultados obtidos foram submetidos ao teste t de Student para amostras independentes (p? 0,05). Os Masseteres masculinos mensurados apresentaram-se maiores que os femininos em ambos os grupos. Nos participantes dos Grupos A e B a largura e o comprimento dos músculos Masseteres, esquerdo e direito, são em média 23% e 12%, respectivamente, maiores no sexo masculino. Entretanto não foram encontradas diferenças na espessura desse músculo entre os indivíduos portadores e não portadores de disfunção temporomandibular.Conclusão: A mensuração da espessura do músculo Masseter, por imagens ultrassonográficas, é inconclusiva para o diagnóstico da disfunção temporomandibular.

Avaliação pelo MEF da distribuição das tensões no implante, componentes protéticos e coroa, em conexões com hexágono externo, interno e Cone Morse / Evaluation using FEM on the stressdistribution on the implant, prostheticcomponents and crown, with Cone Morse, external and internal hexagon connections

Objetivo: comparar a distribuição de tensões em sistemas de implantes com diferentes tipos de conexões (hexágono externo, hexágono interno e Cone Morse), pelo Método de Elementos Finitos Bidimensional. Métodos: uma força de 100N foi aplicada na cúspide vestibular de um segundo pré-molar inferior, no sentido axial, e, posteriormente, com inclinação de 45o em cada sistema. As análises foram realizadas pelos critérios das tensões de von Mises. Resultados: os resultados apontaram que, em todos os três sistemas, a maior concentração de tensões deu-se na região do pescoço do implante em contato com o osso cortical, com exceção do sistema Cone Morse, onde a tensão se concentrou na porção interna do implante em contato com o pilar. Também foi observado que cargas inclinadas sempre geraram valores superiores aos obtidos com as cargas axiais. Conclusão: pode-se concluir, então, que os parafusos dos pilares são a porção mais frágil dos sistemas. Nos implantes, os sistemas com conexão interna têm distribuição mais uniforme das tensões que o de conexão externa.

Objective: The aim of this study was to compare the stress distribution between implant systems with differenttypes of connections, i.e., external hexagon, internal hexagon and morse taper, by applying the Two-DimensionalFinite Element Method. Methods: A 100-N load was applied to the buccal cusp of an inferior second premolar inthe axial direction and thereafter at an inclination of 45o on each system. Analysis was performed by means ofthe von Mises stresses criteria. Results: The results showed that in, all systems, the highest stress concentrationoccurred in the neck of the implant in contact with the cortical bone, except for the morse taper models, where thestress was concentrated in the inner portion of the implant in contact with the abutment. It also became apparentthat oblique forces resulted in higher stress values than those obtained with axial loads. Conclusion: It could beconcluded that abutment screws are the most fragile portion of the systems. Internal connection implant systemsexhibited a more uniform distribution of stresses than external connection implant systems.

Análise comparativa pelo método dos elementos finitos da distribuição de tensões em pilares de próteses fixas implantossuportadas por implantes distais retos e inclinados / Comparative finite element analysis of stress distribution on abutments of fixed dentures supported by vertical and tilted posterior implants

Introdução: o conceito all-on-four preconiza a inclinação dos implantes distais com o objetivo de reduzir o cantiléver distal. Objetivo: avaliar a biomecânica através da análise com elementos finitos tridimensionais, a inclinação dos implantes distais e a utilização de componentes protéticos angulados e retos no tratamento de mandíbulas edêntulas. Métodos: quatro modelos tridimensionais de mandíbula foram criados simulando tecido ósseo cortical e medular. Foram instalados nos modelos quatro implantes paralelos com componentes protéticos retos, dois implantes retos com os dois implantes distais inclinados em 17 ou 30° com componentes protéticos retos ou angulados. Todos os modelos foram carregados axialmente ou obliquamente bilateral, ou unilateralmente em toda a extensão da prótese. Resultados: o uso de implantes retos e os componentes angulados apresentaram maiores concentrações de tensões. A inclinação distal dos implantes favoreceu a distribuição de tensões. Conclusão: o conceito all-on-four com o uso de componentes protéticos retos favorece a biomecânica de reabilitações totais implantossuportadas.

Effectiveness of 980-mm diode and 1064-nm extra-long-pulse neodymium-doped yttrium aluminum garnet lasers in implant disinfection.

OBJECTIVE: To evaluate the potential of 980-nm gallium aluminum arsenide (GaAlAs) and 1064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers to reduce bacteria after irradiation of implant surfaces contaminated with Enterococcus faecalis and Porphyromonas gingivalis and on irradiated implant surface morphology. BACKGROUND: Despite the frequency of implant success, some implant loss is related to peri-implantitis because of difficulty in eliminating the biofilm. METHODS: Implants (3.75 x 13 mm) with machined surfaces, surfaces sand blasted with titanium oxide (TiO(2)), and sand-blasted and acid-etched surfaces were exposed to P. gingivalis and E. faecalis cultures and irradiated with 980-nm GaAlAs or 1064-nm Nd:YAG lasers. After laser treatments, the number of remaining colony-forming units and implant surface morphology were analyzed using scanning electron microscopy (SEM). RESULTS: The Nd:YAG laser was able to promote a total contamination reduction on all implants irradiated. The results with the GaAlAs laser showed 100% bacteria reduction on the implants irradiated with 3 W. Irradiation with 2.5 W and 3 W achieved 100% of bacteria reduction on P. gingivalis-contaminated implants. Decontamination was not complete for the sand-blasted TiO(2) (78.6%) and acid-etched surfaces (49.4%) contaminated with E. faecalis and irradiated with 2.5 W. SEM showed no implant surface changes. CONCLUSION: The wavelengths used in this research provided bacteria reduction without damaging implant surfaces. New clinical research should be encouraged for the use of this technology in the treatment of peri-implantitis.

Disinfection of irreversible hydrocolloid impressions with sodium hypochlorite steam: assessment of antimicrobial efficacy / Desinfecção de moldes de hidrocolóide irreversível com vapor de hipoclorito de sódio: avaliação da eficácia antimicrobiana

Purpose: To evaluate the antimicrobial effectiveness of 2.5% and 5.25% sodium hypochlorite steam to disinfect an irreversible hydrocolloid impressions in Humidifier and Nebulizer Boxes. Methods: The study used a total of 80 quadrant impressions of patients, divided into 4 experimental groups of 20 samples each, with respective controls. The impressions were placed in an atmosphere of sodium hypochlorite with 100% relative humidity for 10 min. After disinfection, each impression was immersed in saline solution that was ultrasonically vibrated. Microbiological analysis of the solution was carried out by counting colonies grown in BHI-agar culture medium after 24 hours in an incubator at 37ºC. The data were analyzed using Wilcoxon's t test. Results: In all groups, it was found that the mean number of colonies in control groups was higher then in the experimental groups (P<0.0001). There was a significant difference between using the Nebulizer Box and the Humidifier Box when 2.5% sodium hypochlorite was used. At a concentration of 5.25% there was no statistical difference between the mean numbers of colonies for the two methods (P>0.01). Conclusion: Sodium hypochlorite at 5.25% can be used for disinfection in the Humidifier Box and Nebulizer Box methods. However, at a 2.5% concentration it is only effective in the Nebulizer box method.

Objetivo: avaliar a eficácia antimicrobiana do vapor de hipoclorito de sódio 2,5% e 5,25% na desinfecção de moldes de hidrocolóide irreversível em Caixa Umidificadora e Caixa Nebulizadora. Metodologia: Utilizaram-se 80 moldes de hemiarcos de pacientes, distribuídos em 4 grupos experimentais de 20 amostras cada, com respectivos controles. Os moldes permaneceram 10 min em atmosfera de hipoclorito de sódio com 100% de umidade relativa. Após desinfecção, cada molde foi imerso em soro fisiológico sob vibração ultrassônica e a análise microbiológica dessa solução foi realizada pela contagem de colônias que cresceram em meio de cultura BHI-ágar após 24h em estufa incubadora a 37ºC. Os dados foram analisados pelo teste t de Wilcoxon. Resultados: Em todos os grupos observou-se maior número médio de colônias dos grupos controles em relação aos experimentais (P<0,0001). Para 2,5% de hipoclorito de sódio houve diferença estatística significativa entre Caixa Nebulizadora e Caixa Umidificadora. A concentração 5,25% não demonstrou diferença estatística entre os números médios de colônias nos dois métodos utilizados (P>0,01). Conclusão: Hipoclorito de sódio 5,25% poderá ser utilizado para desinfecção nos métodos Caixa Umidificadora e Caixa Nebulizadora, no entanto, a concentração 2,5%, só será eficaz quando utilizada no método Caixa Nebulizadora.

Disinfection of irreversible hydrocolloid impressions with sodium hypochlorite steam: assessment of surface roughness and dimensions of gypsum models / Desinfecção de moldes de hidrocolóide irreversível com vapor de hipoclorito de sódio: avaliação dimensional e rugosidade superficial dos modelos de gesso

Purpose: To evaluate the surface roughness and dimensional stability of types III and IV gypsum models, obtained from irreversible hydrocolloid impressions after disinfection with 5.25% sodium hypochlorite steam.Methods: The impressions to obtain type III and type IV gypsum models were divided into 3 groups: Group 1 (disinfection with 5.25% sodium hypochlorite steam for 10 minutes);Group 2 (simulated disinfection with distilled water steam) and Group 3 (no treatment). To measure the dimensional changes with a digital caliper, 36 models (18 for each type of gypsum) were cast according to a stainless steel master model with four pillars. For the surface roughness measurement, 36 gypsum models were cast from the impressions of the polished stainless steel platform. The data were analyzed using ANOVA and Tukey’s test (α=1%).Results: There was no statistically significant difference in linear dimensions or surface roughness when the different disinfection treatments were compared (Groups 1, 2 and 3), for all types of gypsum. Conclusion: The disinfection treatments with sodium hypochlorite steam and distilled water steam for irreversible hydrocolloid impressions did not significantly affect the dimensional stability and surface roughness of the types III and IV gypsum dental models.

Proposição: Avaliar o comportamento dimensional e rugosidade superficial de modelos de gesso tipos III e IV, obtidos em moldes de hidrocolóide irreversível desinfetados com vapor de hipoclorito de sódio 5,25%. Metodologia: Os moldes para obtenção dos modelos de gesso tipo III e tipo IV foram designados: Grupo 1 (desinfecção com vapor de hipoclorito de sódio 5,25% por 10 minutos); Grupo 2 (simulação de desinfecção com vapor de água destilada) e Grupo 3 (sem tratamento). Para medição das alterações dimensionais, moldou-se modelo mestre de aço inox com quatro pilares e confeccionou-se 36 modelos (18 para cada tipo de gesso) e as distâncias foram mensuradas com paquímetro digital. Para leitura da rugosidade, confeccionaram-se 36 modelos a partir de moldes de plataforma de aço inox polida e avaliou-se a superfície dos gessos com rugosímetro. Os dados foram submetidos à análise de variância e teste de Tukey (α=1%). Resultados: Na medição das dimensões lineares entre pilares e leitura da rugosidade superficial, não houve diferença estatística significativa, quando comparados os tipos de tratamento (Grupos 1, 2 e 3) em nenhum dos tipos de gesso. Conclusão: Os tratamentos dos moldes de hidrocolóide irreversível com vapor de hipoclorito de sódio e água destilada não afetaram significantemente a estabilidade dimensional e a rugosidade superficial dos modelos de gesso tipo III e tipo IV.

Clinical and histopathological analysis of intramucosal zirconia inserts used for improving maxillary denture retention.

Intramucosal inserts made of zirconia ceramic have been used for the rehabilitation of edentulous patients. This study aimed to follow up on patients with complete dentures having intramucosal zirconia inserts and to perform a histological analysis of biopsies of the epithelium surrounding the inserts. Twelve 31-66-year-old subjects of both genders received complete denture treatment having the intramucosal inserts in place. Detailed clinical, prosthetic and surgical procedures were described. Clinical exams were done on postoperative days 3, 7, 15, 120 and 360. One year after denture placement, the subjects received local anesthesia and the tissues surrounding the insertion sites in the alveolar ridge were removed using a scalpel blade. Biopsies were fixed for up to 48 h in 10% phosphate-buffered formaldehyde and 5-microm-thick sections were cut and stained with hematoxylin and eosin and Gomori Trichrome. Immunohistochemistry was used to identify endothelium (anti-CD3) and T lymphocytes (anti-CD31). Removing and reinserting the denture was painful until day 15, but all patients reported a marked increase in the retention and stability of the complete denture with little or no discomfort after 30 days. The histopathological analysis showed that zirconia inserts were well tolerated by the oral mucosa, with the presence of collagen fibers in the tissue around the insert, with mild inflammatory response and allowing reepithelialization, expressed by parakeratosis, epithelial hyperplasia and presenting granular layer. In conclusion, intramucosal zirconia inserts did not affect the health of oral mucosa and provide adequate retention and stability of the complete denture and comfort to the patients.

Modelos de prótese parcial removível e comunicação entrecirurgiões-dentistas e técnicos nos laboratórios na cidade de Teresina, Piauí / Removable partial denture models and comunication among dentists andlaboratory technicians in the city of de Teresina, Piauí, Brazil

Objetivo: Avaliar a qualidade dos modelos para a confecção de próteses parciais removíveis. Métodos: Foram analisados 140 modelos em cinco laboratórios de prótese dentária da cidade de Teresina, Piauí, registrados no Conselho Regional de Odontologia. Uma ficha foi aplicada, com 14 questões fechadas e os dados coletados foram submetidos à análise estatística utilizando-se o programa SPSS. Os modelos foram analisados à luz natural ou artificial e fotografados para fins de registro e ilustração. Resultados: Os resultados demonstraram que em 100% dos casos o material de moldagem utilizado foi o alginato, sendo 96,43% dos modelos vazados pelo cirurgião-dentista. Destes, 64,47% foram vazados em gesso pedra e 36,43% em gesso especial. De acordo com critérios como qualidade de superfície, reprodução de detalhes, presença de bolhas e/ou nódulos, reprodução adequada da área edentada, 78,57% dos modelos foram considerados inadequados. Os modelos foram, na sua maioria (96,43%), montados em articulador pelo técnico de prótese dentária, sendo que apenas um cirurgião-dentista encaminhou o registro para montagem dos modelos. O articulador tipo charneira foi utilizado em 97,14% das montagens. Em 94,29% dos casos o planejamento e desenho não foram executados pelo cirurgião-dentista e em 87,86% dos casos nenhuma evidência de preparo de boca foi encontrada. A comunicação entre o cirurgião-dentista e o técnico de prótese dentária foi, na sua maioria, feita por telefone, em 80% dos casos. Conclusão: Deste modo, constatou-se que a prótese parcial removível continua sendo negligenciada em relação à sua confecção clínica e laboratorial, através de uma transferência excessiva de responsabilidades do cirurgião-dentista ao técnico de prótese dentária e de uma comunicação ineficaz entre ambos.

Objective: To evaluate the quality of models for making removable partial dentures. Methods: In this Study, 140 models were analysed in 05 dental prosthesis laboratories in the city of Teresina, Piauí, Brazil, registered with the Conselho Regional de Odontologia. A form containing 14 closed questions was applied, and the data collected were submitted to statistical analysis using the SPSS program. The models were analysed under natural or artificial light and photographed for record and illustration purposes. Results: The results showed that in 100% of the cases the molding material used was alginate, and 93.43% of the models were poured by the dentist. Of these, 64.47% were poured in stone plaster and 36.43% in special plaster. According to criteria such as surface quality, reproduction of details, presence of bubbles and/or nodules, adequate reproduction of the edentulous area, 78.57% of the models were considered inadequate. The majority of the models (96.43%), were mounted in an articulator by the Dental Laboratory Technician, but only 1 dentist sent the record for mounting the models. The hinge type articulator was used in 97.14% of the mountings. In 94.29% of the cases, the planning and design were not executed by the dentist and in 87.86% of the cases no evidence of mouth preparation was found. In 80% of the cases, communication between the dentist and the Dental Laboratory Technician was done by telephone. Conclusion: Thus it was verified that the removable partial denture continues to be neglected as regards its clinical and laboratorial fabrication, through an excessive transfer of responsibilities from the dentist to the Dental Laboratory Technician and an inefficient communication between the two.

Clinical and histopathological analysis of intramucosal zirconia inserts used for improving maxillary denture retention

Intramucosal inserts made of zirconia ceramic have been used for the rehabilitation of edentulous patients. This study aimed to follow up on patients with complete dentures having intramucosal zirconia inserts and to perform a histological analysis of biopsies of the epithelium surrounding the inserts. Twelve 31-66-year-old subjects of both genders received complete denture treatment having the intramucosal inserts in place. Detailed clinical, prosthetic and surgical procedures were described. Clinical exams were done on postoperative days 3, 7, 15, 120 and 360. One year after denture placement, the subjects received local anesthesia and the tissues surrounding the insertion sites in the alveolar ridge were removed using a scalpel blade. Biopsies were fixed for up to 48 h in 10 percent phosphate-buffered formaldehyde and 5-µm-thick sections were cut and stained with hematoxylin and eosin and Gomori Trichrome. Immunohistochemistry was used to identify endothelium (anti-CD3) and T lymphocytes (anti-CD31). Removing and reinserting the denture was painful until day 15, but all patients reported a marked increase in the retention and stability of the complete denture with little or no discomfort after 30 days. The histopathological analysis showed that zirconia inserts were well tolerated by the oral mucosa, with the presence of collagen fibers in the tissue around the insert, with mild inflammatory response and allowing reepithelialization, expressed by parakeratosis, epithelial hyperplasia and presenting granular layer. In conclusion, intramucosal zirconia inserts did not affect the health of oral mucosa and provide adequate retention and stability of the complete denture and comfort to the patients.

Regeneração óssea em Odontologia com a utilização do substituto ósseo composto xenogênico Gen Mix / Bone regeneration in Dentistry with use of composed bone substitute Gen Mix

O presente estudo avaliou quatro casos clínicos onde um xenoenxerto bovino composto osteossubstituto foi usado para regeneração da perda óssea. Três casos de alvéolos dentais pós-extração atraumática e um caso de procedimento de elevação de seio maxilar usando técnica de reposição lateral, objetivando a colocação de implante, foram tratados com xenoenxerto composto. Quatro a oito meses, previamente à colocação de implante, as áreas enxertadas foram reoperadas e biópsias ósseas removidas por brocas trefinas. Após seis meses da colocação dos implantes, os elementos protéticos estiveram em função e mostrando sucesso clínico. A análise histológica das biópsias mostrou ausência de infiltrado inflamatório e presença de tecido ósseo neoformado fora e dentro de poros e fendas do biomaterial. O xenoenxerto foi biocompatível e permitiu a aposição de novo osso, indicando seu uso antes da colocação de implantes osseointegrados.

The present study evaluated four clinical cases where a xenograft bovine compound bone substitute was used for regeneration of bone loss. Three cases of dental sockets after non-traumatic tooth extractions and one case of maxillary sinus augmentation procedure using the lateral approach technique, aiming further implant placement, were treated with xenograft compound. Four to eight months before implant placement, the grafted areas were reopened and bone biopsies carried out by trephine burs. Six months after implant placement, the prosthetic elements were in function showing clinical success. Histological analysis of biopsies showed absence of inflammatory infiltrate and the presence of new bone tissue over and inside pores and grooves of the biomaterial as well. The xenograft was biocompatible and allowed the apposition of new bone, supporting its use before dental implant placement.

Estudo in vitro do laser de diodo 980nm na desinfecção de implantes / In vitro study of 980nm diode laser in dental implant disinfection

Objetivos: Avaliar o potencial de redução bacteriana do laser de diodo 980nm em três diferentes tipos de superfícies de implantes dentários contaminados com Enterococcus faecalis e Porphyromonas gingivalis, bem como estudar por microscopia eletrônica de varredura possíveis alterações na superfície dos implantes irradiados. Métodos: Foram utilizados 72 implantes com diferentes tratamentos de superfície (usinado; jateados com óxido de titânio; e ataque ácido). Os implantes foram contaminados com duas cepas bacterianas, Enterococcus faecalis e Porphyromonas gingivalis, e, posteriormente, irradiados pelo laser de diodo 980nm, nas potências de 2,5 e 3,0W. Após os tratamentos a laser, o número de unidades formadoras de colônias foi analisado e o grupo controle, não contaminado, mas irradiado pelo laser, foi submetido à microscopia eletrônica de varredura, para a avaliação de possíveis alterações na superfície dos implantes. Resultados: Os resultados mostraram que houve 100% de redução bacteriana nos implantes irradiados com 3,0W, e redução bacteriana total dos implantes contaminados com Porphyromonas gingivalis, mesmo quando irradiados com 2,5W. A redução bacteriana só não foi total para os implantes contaminados com Enterococcus faecalis irradiados com potência de 2,5W e com superfície jateada com TiO2 (78,6%), e com superfície com ataque ácido (49,4%). A análise em microscopia eletrônica de varredura mostrou que, com os parâmetros energéticos utilizados nesta pesquisa, não houve alteração da superfície dos implantes. Conclusão: O laser de diodo 980nm foi efetivo na descontaminação do Enterococcus faecalis e Porphyromonas gingivalis sem promover a alteração na superfície dos implantes.

Objective: To evaluate the potential of 980nm diode laser to reduce bacteria after irradiation of three different dental implant surfaces contaminated with Enterococcus faecalis and Porphyromonas gingivalis, as well as the possible changes in the irradiated implant surfaces. Methods: Seventy two implants with machined surfaces, airborne particle abraded with titanium oxide and acid-etched surfaces were exposed to Enterococcus faecalis and Porphyromonas gingivalis cultures and irradiated with 980nm diode laser with power of 2.5 and 3,0W. After laser treatments, the number of remaining colony-forming units was studied and implant surface morphology was analyzed by scanning electron microscopy. Results: The results showed 100% reduction of the bacteria on the implants irradiated with 3.0W. Moreover, 100% reduction of bacteria was also achieved on the implant surfaces contaminated with Porphyromonas gingivalis when irradiated with 2.5W and 3.0W. Bacteria reduction was not complete for the implants contaminated with Enterococcus faecalis, irradiated with 2.5W and surfaces treated with TiO2 airborne particle abrasion (78.6%) and acid etching (49.4%).The scanning electron microscopy analysis showed that at the power settings used, no implant surface changes were found. Conclusion: The 980nm diode laser was effective in decontaminating the Enterococcus faecalis and Porphyromonas gingivalis without promoting surface alteration in the implants.

Avaliação da precisão de modelos obtidos a partir de diferentes transferentes para implantes HE / Evaluation the accuracy of models obtained through different transfers for implants HE

Objetivo: Avaliar, in vitro, a precisão dos modelos obtidos a partir de transferentes cônicos dos sistemas Nobel Biocare (TB), Conexão (TC), Neodent (TN) e Dentoflex (TD) sobre implantes de hexágono externo (HE) das respectivas marcas (comparação intra-sistemas) e em combinações entre eles (comparação intersistemas). MATERIAIS E MÉTODOS: Sobre uma matriz de aço inox na qual foi instalado um implante de cada sistema citado anteriormente, foram realizadas moldagens utilizando silicone de adição, distribuídas da seguinte forma: Grupo A: TB sobre implante Nobel Biocare (IB), TC sobre implante Conexão (IC), TN sobre implante Neodi:mt (IN) e TD sobre implante Dentoflex (ID); Grupo B: TC sobre IB, TN sobre IC, TD sobre IN e TB sobre ID; Grupo C: TN sobre IB, TD sobre IC, TB sobre IN e TC sobre ID e no Grupo D: TD sobre IB, TB sobre IC, TC sobre IN e TN sobre ID. Os modelos obtidos foram analisados em um projetor de perfil e foram avaliadas as alterações na distância horizontal e na rotação de cada análogo em relação aos implantes instalados no modelo matriz. RESULTADOS: Os resultados intersistemas variaram na distância horizontal entre 0,74% (TB/IB) a 2,28% (TD/ID) e na rotação entre 01°04' (TB/IB) a 09°54' (TD/ID), enquanto que, na comparação intra-sistemas, as alterações na distância horizontal foram de 0,55% (TB/IC) a 2,49% (TC/ID) e na rotação de 01°33' (TB/IN) a 05°54' (TC/ID). CONCLUSÃO: Todos os modelos obtidos nas combinações apresentaram diferenças significativas (p = 0.0048) com os implantes instalados no modelo matriz utilizando o teste ANOVA.

Objective: evaluate the precision of the impression carried through with conical transfers of system Nobel Biocare (TB), Conexão (TC), Neodent (TN) and Dentoflex (TD) on implantations of external hexagon of the respective system and in combinations between them. A matrix model was constructed and on same, installed an implantation of each cited system previously. Metallic tray also was confectioned and the material of choice for all the impressions was the silicone of polymerization for addition. The impressions had been divided in four distributed groups of the following form: Group A: TB on Nobel Biocare implant (IB), TC on Conexão implant (IC), TN on Neodent implant (IN) and TD on Dentoflex implant (ID); Group B: TC on IB, TN on IC, TD on IN and TB on ID; Group C: TN on IB, TD on IC, TB on IN and TC on ID and in Group D: TD on IB, TB on IC, TC on IN and TN on ID. The models had been analyzed in a Projector of Profile where they had been verified in the horizontal distance and the rotation of each analogue in relation to implants installed in the matrix model. Results: inter-systems in horizontal distance ranged between 0,74% (TB/IB) to 2.28% (TD/ID) and the rotation between 01°04' (TB/IB) to 09°54' (TD/ID) while in comparison intra-system changes in horizontal distance was 0.55% (TB/IC) to 2,49% (TC/ID) and the rotation of 01°33 (TB/IN) to 05°54'(TC/ID). Conclusion: All models obtained in combinations showed significant differences (p = 0.0048) using ANOVA test.

Effect of roughness of zirconia and titanium on fibroblast adhesion.

The aim of this study was to investigate the adhesion (4 and 24 h) and the morphology of fibroblast Balb/c 3T3 seeded onto polystyrene, partially stabilized (ZrO(2)Y(2)O(3)), stabilized zirconia ceramic (3YTZP), and pure titanium (Ti, grade 2). Initial cell adhesion (4 h) was greater (P < 0.05, analysis of variance and Tukey's Multiple Comparisons Test) onto ZrO(2)Y(2)O(3) and polystyrene than in Ti and 3YTZ. After 24 h, the number of adhered cells was similar between the biomaterials tested, but smaller than onto polystyrene (P < 0.05). Cells were more spread onto glass surface after 4 h, but after 24 h, the morphology and density of the cells were similar in all groups (SEM). Profilometry showed distinct Ra values for each material: glass coverslips and ZrO(2)Y(2)O(3) (0.09 microm), Ti (0.88 microm), and 3YTZP (30.93 microm). It was concluded that ZrO(2)Y(2)O(3) promoted the best initial adhesion, thus indicating that surfaces with Ra values smaller than 0.1 microm could be more favorable to initial adhesion.

Desinfecção de moldes, modelos e trabalhos protéticos em laboratórios de prótese dentária / Desinfection of molds, stone casts and prosthetic works in dental laboratories

Esta pesquisa teve o objetivo de avaliar como a desinfecção de moldes, modelos e trabalhos é realizada em laboratórios de prótese dentária. Para isso, um questionário foi formulado contendo 6 perguntas objetivas sobre desinfecção e biossegurança. Foram selecionados aleatoriamente 12 laboratórios especializados em prótese dentária da cidade de São Paulo. Os técnicos responsáveis pelo laboratório responderam ao questionário. A conclusão que se pôde chegar foi que os técnicos de laboratório ainda não estão conscientizados sobre os procedimenos relacionados à biossegurança