Effects of Different Polishing Protocols on Lithium Disilicate Ceramics.

The aim of this study was to evaluate the effect of different polishing protocols on surface roughness and morphology of lithium disilicate ceramics (IPS e.max CAD). Fifty ceramic bars (2.0x3.0x2.5 mm) were produced and randomly divided into five groups (n=10), according to surface treatments: C: Control; Cer: Ceramaster (60 s); CW: cloth wheel with large-grit diamond (30 s) + cloth wheel with fine-grit diamond paste (30 s); E: grey Exa-Cerapol (20 s) + pink Exa-Cerapol (20 s) + Cerapol Super (20 s); F: Felt wheel with large-grit diamond paste (30 s) + Felt wheel with fine-grit diamond paste (30 s). The samples were evaluated quantitatively for surface roughness (Ra) and qualitatively by SEM, at different moments: initial (prior to roughening), after roughening and after polishing procedures. Ra means were submitted to two-way ANOVA and Tukey test (p<0.05). After the different polishing protocols, no statistically significant differences were observed between the Cer and E groups (p=0.6347), E and CW groups (p=0.1366), and CW and FW groups (p=0.5433). Comparing different stages in the same group, it was possible to observe that CW (p<0.0001) and FW groups (p<0.0001) showed significant differences. SEM analysis revealed that both Cer and E groups exhibited a surface morphological pattern similar to that of control group. All polishing systems were effective in reducing the surface roughness of the studied ceramic type.

Effects of Different Polishing Protocols on Lithium Disilicate Ceramics

Abstract: The aim of this study was to evaluate the effect of different polishing protocols on surface roughness and morphology of lithium disilicate ceramics (IPS e.max CAD). Fifty ceramic bars (2.0x3.0x2.5 mm) were produced and randomly divided into five groups (n=10), according to surface treatments: C: Control; Cer: Ceramaster (60 s); CW: cloth wheel with large-grit diamond (30 s) + cloth wheel with fine-grit diamond paste (30 s); E: grey Exa-Cerapol (20 s) + pink Exa-Cerapol (20 s) + Cerapol Super (20 s); F: Felt wheel with large-grit diamond paste (30 s) + Felt wheel with fine-grit diamond paste (30 s). The samples were evaluated quantitatively for surface roughness (Ra) and qualitatively by SEM, at different moments: initial (prior to roughening), after roughening and after polishing procedures. Ra means were submitted to two-way ANOVA and Tukey test (p<0.05). After the different polishing protocols, no statistically significant differences were observed between the Cer and E groups (p=0.6347), E and CW groups (p=0.1366), and CW and FW groups (p=0.5433). Comparing different stages in the same group, it was possible to observe that CW (p<0.0001) and FW groups (p<0.0001) showed significant differences. SEM analysis revealed that both Cer and E groups exhibited a surface morphological pattern similar to that of control group. All polishing systems were effective in reducing the surface roughness of the studied ceramic type.

Resumo: O objetivo deste estudo foi avaliar o efeito de diferentes protocolos de polimento sobre a rugosidade e morfologia superficial de uma cerâmica à base de dissilicato de lítio (IPS e.max CAD). Foram confeccionadas 50 barras cerâmicas (2,0x3,0x2,5 mm), separadas aleatoriamente em cinco grupos (n=10), conforme os tratamentos de superfície: C: Controle; BC: Borracha Ceramaster (60 s); RP: Roda de pano impregnado granulação grossa (30 s) + Roda de pano impregnado granulação fina (30 s); BE: Borracha Exa-Cerapol cinza (20 s) + Borracha Exa-Cerapol rosa (20 s) + Borracha Cerapol Super (20 s); RF: Roda de feltro com pasta diamantada grossa (30 s) + roda de feltro com pasta diamantada fina (30 s). As amostras foram avaliadas quantitativamente quanto à rugosidade superficial (Ra) e qualitativamente em MEV, em diferentes momentos: inicialmente (antes da asperização), após asperização e após os polimentos. As médias de Ra foram submetidas aos testes estatísticos ANOVA (two-way) e Tukey (p<0,05). Após os diferentes protocolos de polimento, não foi possível observar diferenças significativas entre os grupos BC e BE (p=0,6347), entre BE e RP (p=0,1366) e RP e RF (p=0,5433). Comparando as diferentes etapas de um mesmo grupo foi possível observar que os grupos RP (p<0,0001) e RF (p<0,0001) apresentaram diferenças significativas. Em MEV, os grupos BC e BE apresentam um padrão morfológico superficial semelhante ao grupo controle. Todos os sistemas de polimento foram efetivos na redução da rugosidade de superfície para o mesmo padrão de cerâmica.

Avaliação in vitro do efeito das tinturas de Camellia sinensis e de Aloe arborescens na remineralização de lesão de cárie artificial em esmalte dentário humano / In vitro remineralizing effect of Camellia sinensis and Aloe arborescens tinctures in subsurface carious lesions developed in human dental enamel

O estudo avaliou a efetividade das tinturas de Camellia sinensis e deAloe arborescens na remineralização de lesão artificial de cáriesubsuperficial no esmalte dentário humano. Noventa espécimes demolares permanentes hígidos foram distribuídos em 6 grupos (n=15):GH=esmalte hígido e saliva artificial, GS=esmalte cariado e salivaartificial, GA=esmalte cariado e água deionizada, GF=esmalte cariado esolução aquosa de fluoreto de sódio 0,05%, GC=esmalte cariado e tinturade C. sinensis e GB=esmalte cariado e tintura de A. arborescens. Amicrodureza superficial foi mensurada nos espécimes quando hígidos(KHN1), após a formação da lesão de cárie (KHN2) e após ostratamentos (KHN3). A microdureza em secção transversa (KHND) foimensurada para avaliação da profundidade da lesão. Um espécime decada grupo foi submetido: ao EDS, para avaliar a razão Ca/P do esmalte;ao MEV, para verificar alterações topográficas na superfície e à MLPpara comprovar histologicamente a formação da lesão de cárie. Aporcentagem do volume de conteúdo mineral foi realizada com asmédias KHN3 e KHND. As médias dos valores de microdureza foramsubmetidas aos testes estatísticos ANOVA, Tukey comparaçõesmúltiplas, Dunnettt comparações múltiplas e t pareado (p<0,05). Houveaumento nos valores de microdureza superficial e em secção transversaapós os tratamentos, assim como do conteúdo mineral, com exceção deGA. Concluiu-se que os tratamentos foram efetivos na remineralizaçãoda lesão de cárie tanto na microdureza superficial quanto em secçãotransversa, quando comparados a GA. Todos os tratamentos diminuírama profundidade da lesão, com destaque para a solução de NaF, seguidopela tintura de C. sinensis, saliva e tintura de A. arborescens.

This in vitro study evaluated the effectiveness of Camellia sinensis andAloe arborescens tinctures in the remineralization of subsurface cariouslesions artificially developed in human dental enamel. Ninety specimensfrom sound permanent molars were distributed into 6 groups (n=15):GH=sound enamel and artificial saliva, GS=decayed enamel andartificial saliva, GA=decayed enamel and deionized water, GF=decayedenamel and 0.05% sodium fluoride aqueous solution, GC=decayedenamel and C. sinensis tincture and GB=decayed enamel and A.arborescens tincture. Surface microhardness essay was performed onsound specimens (KHN1), after the caries lesion development (KHN2)and after treatment (KHN3). Cross-sectional microhardness essay(KHND) was performed to measure the lesion depth. One specimen ofeach group was submitted to: EDS to assess the enamel Ca/P ratio; SEMto verify topographical changes on the enamel surface and to the MLP toreveal the histological aspects of carious lesions. The volume percent ofmineral content was performed with the KHN3 and KHND averages. Themicrohardness averages were submitted to the following statisticalanalyzes: ANOVA, Tukey multiple comparisons, Dunnettt multiplecomparisons and paired t test (p<0.05). There was an increase in thesurface and cross-sectional microhardness values after treatments, as well as in the mineral content, except for GA. It was concluded that thetreatments were effective in remineralization of dental caries on thesurface and on the cross-sectional microhardness essays, whencompared to GA. All treatments reduced the depth of the lesion,especially the NaF solution, followed by C. sinensis, saliva and A.arborescens.

Avaliação in vitro do efeito das tinturas de Camellia sinensis e de Aloe arborescens na remineralização de lesão de cárie artificial em esmalte dentário humano / In vitro remineralizing effect of Camellia sinensis and Aloe arborescens tinctures in subsurface carious lesions developed in human dental enamel

O estudo avaliou a efetividade das tinturas de Camellia sinensis e deAloe arborescens na remineralização de lesão artificial de cáriesubsuperficial no esmalte dentário humano. Noventa espécimes demolares permanentes hígidos foram distribuídos em 6 grupos (n=15):GH=esmalte hígido e saliva artificial, GS=esmalte cariado e salivaartificial, GA=esmalte cariado e água deionizada, GF=esmalte cariado esolução aquosa de fluoreto de sódio 0,05%, GC=esmalte cariado e tinturade C. sinensis e GB=esmalte cariado e tintura de A. arborescens. Amicrodureza superficial foi mensurada nos espécimes quando hígidos(KHN1), após a formação da lesão de cárie (KHN2) e após ostratamentos (KHN3). A microdureza em secção transversa (KHND) foimensurada para avaliação da profundidade da lesão. Um espécime decada grupo foi submetido: ao EDS, para avaliar a razão Ca/P do esmalte;ao MEV, para verificar alterações topográficas na superfície e à MLPpara comprovar histologicamente a formação da lesão de cárie. Aporcentagem do volume de conteúdo mineral foi realizada com asmédias KHN3 e KHND. As médias dos valores de microdureza foramsubmetidas aos testes estatísticos ANOVA, Tukey comparaçõesmúltiplas, Dunnettt comparações múltiplas e t pareado (p<0,05). Houveaumento nos valores de microdureza superficial e em secção transversaapós os tratamentos, assim como do conteúdo mineral, com exceção deGA. Concluiu-se que os tratamentos foram efetivos na remineralizaçãoda lesão de cárie tanto na microdureza superficial quanto em secçãotransversa, quando comparados a GA. Todos os tratamentos diminuírama profundidade da lesão, com destaque para a solução de NaF, seguidopela tintura de C. sinensis, saliva e tintura de A. arborescens

This in vitro study evaluated the effectiveness of Camellia sinensis andAloe arborescens tinctures in the remineralization of subsurface cariouslesions artificially developed in human dental enamel. Ninety specimensfrom sound permanent molars were distributed into 6 groups (n=15):GH=sound enamel and artificial saliva, GS=decayed enamel andartificial saliva, GA=decayed enamel and deionized water, GF=decayedenamel and 0.05% sodium fluoride aqueous solution, GC=decayedenamel and C. sinensis tincture and GB=decayed enamel and A.arborescens tincture. Surface microhardness essay was performed onsound specimens (KHN1), after the caries lesion development (KHN2)and after treatment (KHN3). Cross-sectional microhardness essay(KHND) was performed to measure the lesion depth. One specimen ofeach group was submitted to: EDS to assess the enamel Ca/P ratio; SEMto verify topographical changes on the enamel surface and to the MLP toreveal the histological aspects of carious lesions. The volume percent ofmineral content was performed with the KHN3 and KHND averages. Themicrohardness averages were submitted to the following statisticalanalyzes: ANOVA, Tukey multiple comparisons, Dunnettt multiplecomparisons and paired t test (p<0.05). There was an increase in thesurface and cross-sectional microhardness values after treatments, as well as in the mineral content, except for GA. It was concluded that thetreatments were effective in remineralization of dental caries on thesurface and on the cross-sectional microhardness essays, whencompared to GA. All treatments reduced the depth of the lesion,especially the NaF solution, followed by C. sinensis, saliva and A.arborescens

Polishing for glass ceramics: which protocol?

PURPOSE: The execution of adjustments on ceramic restorations is sometimes necessary for either correction of occlusion and/or inadequate contours or esthetical improvements. Clinically, the surfaces undergo weariness through fine grinding diamond burs which remove the superficial glazing layer. Several materials for ceramic polishing have been used in an attempt to reach a satisfactory surface smoothness. The aim of this study was to perform a literature review on different polishing protocols of several dental ceramics. STUDY SELECTION: This is a literature review performed through scientific articles published between 2004 and 2012, indexed in MEDLINE, PubMed and Scielo databases. The study selected and analyzed a total of 20 relevant articles that evaluated different types of ceramics, polishing treatment and surface roughness. RESULTS: After an extensive literature review, this study observed: 1 - after the rupture of the glazing layer due to the adjustments of the restorations, the best choice for the polishing of the surface will depend on the type of ceramics used; 2 - glazing procedure provide excellent results regarding to the superficial smoothness; however, if reglazing is impossible, either abrasive rubber cups/points or sandpaper discs followed by the use of diamond polishing pastes results in a satisfactory superficial smoothness; 3 - clinical studies that take into account the behavior of the protocols polishing are scarce and should be encouraged; 4 - the large number of variables influence the final outcome of polishing should be considered. CONCLUSIONS: The necessity in standardization of methodologies to enable a comparison among researches.

Orthodontic extrusion and implant site development: two case reports / Extrusão ortodôntica pré-implante: relato de dois casos clínicos

The aim of this study was to report two cases of orthodontic extrusion performed prior to dental implant placement. The first one reports the case of a 57 year-old-female who presented internal root resorption in the left central incisor, and orthodontic extrusion of this element was indicated. The treatment lasted 24 weeks. At the end of this period, the dental implant was placed. The second clinical event refers to a patient of 66 years of age who had vertical fracture in the left central incisor. In this case, the orthodontic extrusion was conducted in 12 weeks. At the end of this period, the dental implant was placed and also the temporary crown, but without occlusal contact. Both cases reported consisted of the involvement of the left central incisor in the aesthetic area and low bone density. The cases reported demonstrated that orthodontic extrusion is a viable alternative to the aesthetic and functional reconstruction with prosthesis over dental implants...

A extrusão ortodôntica é um procedimento clínico utilizado no decorrer dos anos com a finalidade, dentre outras, de preservação e ganho de tecido ósseo para permitir a restauração estética e funcional. Assim, este trabalho teve por objetivo relatar dois casos de extrusão ortodôntica realizada previamente à colocação do implante dentário. O primeiro deles relata o caso de uma paciente de 57 anos de idade que apresentou reabsorção interna no incisivo central esquerdo sendo indicada a sua extrusão ortodôntica. O tratamento durou 24 semanas. Ao final deste período foi colocado o implante no local. O segundo caso clínico refere-se a um paciente de 66 anos de idade que apresentou fratura vertical no incisivo central esquerdo. Optou-se por realizar extrusão ortodôntica, por um período de 12 semanas. Finalizado este período, foi realizada a colocação de implante e provisório sem contato oclusal. Observou-se nestes relatos que ambos os casos apresentados consistiram no comprometimento do incisivo central esquerdo, em área estética e de pouca densidade óssea. Esses dois casos demonstraram a extrusão ortodôntica como uma alternativa viável para a reconstrução estética e funcional com prótese sobre implante...

Disinfection protocols to prevent cross-contamination between dental offices and prosthetic laboratories.

Control of cross-contamination between dental offices and prosthetic laboratories is of utmost importance to maintain the health of patients and dental office staff. The purpose of this study was to evaluate disinfection protocols, considering antimicrobial effectiveness and damage to the structures of prostheses. Solutions of 1% sodium hypochlorite, 2% chlorhexidine digluconate, 50% vinegar and sodium perborate were evaluated. Specimens were contaminated in vitro with standardized suspensions of Candida albicans, Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Bacillus subtilis spores. Disinfection by immersion for 10 min was performed. Final counts of microorganisms were obtained using the plating method. Results were statistically compared by Kruskal-Wallis ANOVA and Dunn's test. The surface roughness of 40 specimens was analyzed before and after 10 disinfection cycles, and results were compared statistically using Student's t test. The solution of 50% vinegar was as effective as 1% sodium hypochlorite and 2% chlorhexidine against C. albicans, E. coli and S. mutans. The sodium perborate solution showed the lowest antimicrobial effectiveness. Superficial roughness increased after cycles in 1% sodium hypochlorite (p=0.02). Solutions of 1% sodium hypochlorite, 2% chlorhexidine and 50% vinegar were effective for the disinfection of heat-polymerized acrylic specimens. Sodium hypochlorite increased the superficial roughness.

Hydroxyurea therapy in sickle cell anemia patients aids to maintain oral fungal colonization balance.

BACKGROUND: The aim of this study was to evaluate the frequency of Candida species and presence of lesions in the oral cavity of patients with sickle cell anemia (SS). METHODS: The study included 30 patients diagnosed with sickle cell anemia and taking hydroxyurea for at least 90 days (SS/HU+); and 39 patients with sickle cell anemia and without hydroxyurea therapy (SS/HU-). Two control groups were constituted by healthy individuals matched to the test groups in age, gender, and oral conditions (C/HU+ for SS/HU+ and C/HU- for SS/HU-). Oral clinical examination and anamnesis were performed. Yeasts were collected by oral rinses and identified by API system. Antifungal susceptibility evaluation was performed according to the CLSI methodology. Data obtained for microorganisms counts were compared by Student's t test (SS/HU+ vs. C/HU+ and SS/HU- vs. C/HU-) using MINITAB for Windows 1.4. Significance level was set at 5%. RESULTS: No oral candidosis lesions were detected. Significant differences in yeasts counts were observed between SS/HU- group and the respective control, but there were no differences between SS/HU+ and C/HU+. Candida albicans was the most prevalent species in all groups. Candida famata was observed both in SS and control groups. Candida dubliniensis, Candida glabrata, Candida krusei, Candida tropicalis, Candida pelliculosa, and Candida parapsilosis were observed only in SS groups. Most strains were susceptible to all antifungal agents. CONCLUSION: Hydroxyurea therapy seems to decrease candidal counts and resistance rate in sickle cell anemia patients. However, further studies should be conducted in the future to confirm this finding. Hydroxyurea therapy in sickle cell anemia patients maintains fungal species balance in oral cavity.

Fracture resistance of bovine incisors restored with different glass fiber posts: effect of the diameter of fiber post.

AIM: Compare the effect of three post designs on the fracture resistance and failure modes of composite core - fiber post - crownless tooth sets. MATERIALS AND METHODS: Ninety bovine incisors were selected and divided into nine groups of 10 specimens. The teeth were assigned to three groups based on the post design: Cylindrical, tapered, and double-tapered. Each group was subdivided into three subgroups in accordance with the diameter of the post: Small (No.1), medium (No.2), and large (No.3). The Panavia F system was used for post cementation. The specimens were mounted in acrylic resin blocks with a layer of silicone rubber covering the roots. A universal testing machine compressively loaded the specimens from the palatal side at a crosshead speed of 1 mm/min and at an angle of 135Ί to the long axis of the teeth, until failure occurred. The failure mode was determined by a stereomicroscope inspection of all the specimens. Data were analyzed by one-way ANOVA and the Tukey test (P < 0.05). RESULTS: The fracture resistance was affected by the type of post (P < 0.0001). A narrower diameter for all of the post systems allowed for higher resistance. The main failure mode in the large cylindrical group was catastrophic fractures, while the main failures in the other eight groups were favorable. CONCLUSION: Narrower diameter posts showed higher fracture resistance. The dominant failure pattern was repairable fracture, except for those with large cylindrical groups.

Effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones.

The aim of this study was to evaluate the effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones contaminated in vitro with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Candida albicans and Bacillus subtilus (in spore form). Two hundred and twenty-five gutta-percha cones were contaminated with standardized suspensions of each microorganism and incubated at 37°C for 24 h. The cones were divided into 10 experimental groups (n = 15), according to the microorganism tested and disinfection testing times. The disinfection procedure consisted of immersing each cone in a plastic tube containing the substance. The specimens remained in contact with the substance for 1 or 2.5 minutes. Afterwards, each cone was transferred to a 10% sodium thiosulphate solution (Na(2)S(2)O(3)) to neutralize the disinfectant. Microbial biofilms adhering to the cones were dispersed by agitation. Aliquots of 0.1 ml of the suspensions obtained were plated on Sabouraud dextrose agar, or brain and heart infusion agar, and incubated at 37°C for 24 h. The results were expressed in colony forming units (CFU/ml) and the data were submitted to the Wilcoxon Signed Rank Test (level of significance at 0.05). A significant reduction was observed, after 1 minute of exposure, in the test solution for C. albicans (p = 0.0190), S. aureus (p = 0.0001), S. mutans (p = 0.0001), B. subtilis (p = 0.0001), and E. coli (p = 0.0001). After 2.5 minutes of exposure, 100% of the microbial inocula were eliminated. It was concluded that the 2% peracetic acid solution was effective against the biofilms of the tested microorganisms on gutta-percha cones at 1 minute of exposure.

Effectiveness of 2 percent peracetic acid for the disinfection of gutta-percha cones

The aim of this study was to evaluate the effectiveness of 2 percent peracetic acid for the disinfection of gutta-percha cones contaminated in vitro with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Candida albicans and Bacillus subtilus (in spore form). Two hundred and twenty-five gutta-percha cones were contaminated with standardized suspensions of each microorganism and incubated at 37°C for 24 h. The cones were divided into 10 experimental groups (n = 15), according to the microorganism tested and disinfection testing times. The disinfection procedure consisted of immersing each cone in a plastic tube containing the substance. The specimens remained in contact with the substance for 1 or 2.5 minutes. Afterwards, each cone was transferred to a 10 percent sodium thiosulphate solution (Na2S2O3) to neutralize the disinfectant. Microbial biofilms adhering to the cones were dispersed by agitation. Aliquots of 0.1 ml of the suspensions obtained were plated on Sabouraud dextrose agar, or brain and heart infusion agar, and incubated at 37°C for 24 h. The results were expressed in colony forming units (CFU/ml) and the data were submitted to the Wilcoxon Signed Rank Test (level of significance at 0.05). A significant reduction was observed, after 1 minute of exposure, in the test solution for C. albicans (p = 0.0190), S. aureus (p = 0.0001), S. mutans (p = 0.0001), B. subtilis (p = 0.0001), and E. coli (p = 0.0001). After 2.5 minutes of exposure, 100 percent of the microbial inocula were eliminated. It was concluded that the 2 percent peracetic acid solution was effective against the biofilms of the tested microorganisms on gutta-percha cones at 1 minute of exposure.

Influência de diferentes dispositivos de microtração nos valores de resistência coesiva / Influence of different devices on microtensile strength

O objetivo deste estudo foi avaliar a influência de dispositivos de microtração sobre a resistência coesiva de blocos de resina acrílica. Vinte blocos de resina acrílica termopolimerizável (Onda-Cryl Clássico) foram confeccionados e distribuídos em 4 diferentes grupos experimentais (n=5) de acordo com o dispositivo de microtração empregado: G1: Paquímetro modificado; G2: Dispositivo de Andreatta Filho; G3: Dispositivo de Borges; G4: MT-jig. Os blocos foram seccionados em palitos de lmm2 e submetidos ao teste de microtração (EMIC DL 1000). Os dados foram avaliados pela Análise de Variância e pelo Teste de Tukey, a 5% de significância. Os menores valores de resistência mecânica foram obtidos com os dispositivos de Andreatta Filho (34,22 MPa) e de Borges (34,49 MPa), e os maiores valores com o Paquímetro modificado (49,44 MPa) e o MT-jig (48,40 MPa). Concluiu-se que os valores de resistência mecânica são influenciados pelos dispositivos de microtração utilizados e que não podem ser comparados entre si.

The aim of this study was to assess the influence of different devices on microlensile strength of acrylic resin blocks. Twenty thermo polyrnerized acrylic resin blocks (Onda-Cryl Clássico) were produced and divided into four experimental groups (n=5) according to microtensile device used: G I: Modified caliper; G2: Andreatta Filho’s device: G3: Borges' device: G4: MT-jig. Blocks were sectioned into sticks with a crosssection of I rnm2- and tested to failure in tension mode (EMIC DL 1000). The data were submitted to l-way analysis of variance (AOVA), followed by Tukey’s test (a=.05). The lowest mean microtensile strengths were obtained with Andreatta Filhos (34.22 MPa) and Borges' (34.49 MPa) devices. Paquimeter (49.44 MPa) and MT-jig (48.40 MPa) promoted the highest mean microtensile strengths, 1t was concluded that microtensile devices influence mechanical strength values.