Susceptibility of fluorotic enamel to dental erosion-abrasion

Abstract Dental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.

Effect of different mechanical surface treatments on flexural strength of repaired denture base / Efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la dentadura reparada

Aim: To assess the effect of different mechanical surface treatments on flexural strength of repaired denture base. Material and Methods: Sixty bar-shaped specimens of heat-polymerized acrylic resin were fabricated, and divided into six groups (n=10). All specimens, except the positive control group (group PC), were sectioned into halves to create a 1-mm clearance. A negative control group with no surface treatment (group NC) was also considered. Other groups underwent different surface treatments: group Laser; treated with erbium: yttrium-aluminum-garnet (Er:YAG) laser, group APA; airborne-particle abrasion (APA), group APA plus Laser; a combination of laser and APA, and group Bur; bur grinding. After measuring surface roughness (Ra) with a profilometer, all sectioned specimens were repaired by auto-polymerizing acrylic resin, and thermocycled afterward. Three-point bending test was performed by a universal testing machine. Data were statistically analyzed (α=0.05). Results: The mean surface roughness of all experimental groups were significantly higher than that of group NC (p<0.05). The mean flexural strength of all groups was significantly lower than that of group PC (p<0.05). Group B had significantly higher flexural strength than the other surface-treated groups (p<0.05). Group Laser had significantly higher flexural strength than groups APA (p=0.043) and APA plus Laser (p=0.023). No significant difference was found between groups APA and APA plus Laser (p=0.684). Conclusion: All surface treatments increased the surface roughness and flexural strength compared with the untreated group. The highest flexural strength was observed in specimens treated by bur grinding and then laser, however, it was still significantly lower than intact specimens.

Objetivo: Evaluar el efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la prótesis reparada. Material y Métodos: Se fabricaron sesenta especímenes en forma de barra de resina acrílica termo-polimerizada y se dividieron en seis grupos (n=10). Todas las muestras, excepto el grupo de control positivo (grupo PC), se seccionaron en mitades para crear un espacio libre de 1 mm. También se consideró un grupo de control negativo sin tratamiento superficial (grupo NC). Otros grupos se sometieron a diferentes tratamientos superficiales: grupo Láser; tratados con láser de erbio: itrio-aluminio-granate (Er:YAG), grupo APA; abrasión por partículas en el aire (APA), grupo APA más láser; una combinación de láser y APA, y grupo Bur; molienda de fresas. Después de medir la rugosidad de la superficie (Ra) con un perfilómetro, todas las muestras seccionadas se repararon con resina acrílica de autopolimerización y se sometieron a termociclado. La prueba de flexión de tres puntos se realizó con una máquina de prueba universal. Los datos se analizaron estadísticamente (α=0,05). Resultados: La rugosidad superficial media de todos los grupos experimentales fue significativamente mayor que la del grupo NC (p<0,05). La resistencia media a la flexión de todos los grupos fue significativamente menor que la del grupo PC (p<0,05). El grupo B tenía una resistencia a la flexión significativamente mayor que los otros grupos tratados en la superficie (p<0,05). El grupo Láser tuvo una resistencia a la flexión significativamente mayor que los grupos APA (p=0,043) y APA más Láser (p=0,023). No se encontró diferencia significativa entre los grupos APA y APA más Láser (p=0,684). Conclusión: Todos los tratamientos superficiales aumentan la rugosidad de la superficie y la resistencia a la flexión en comparación con el grupo sin tratar. La resistencia a la flexión más alta se observó en las muestras tratadas con fresado y luego con láser; sin embargo, aún era significativamente más baja que las muestras intactas.

Surface treatment and adhesion approaches on polymer-infiltrated ceramic network: influence on the bond strength to resin cement

Aim: To evaluate the effect of different surface treatments and adhesive approaches on the microshear bond strength of resin cement to a polymer-infiltrated ceramic network (PICN). Methods: PICN blocks were randomly assigned into 9 groups (n=10): CTRL: no treatment; HF: 5% hydrofluoric acid etching; HF-S: HF + silane; HF-S-A: HF-S + adhesive (Adper Single Bond 2); HF-UA: HF + universal adhesive (Single Bond Universal); SB: sandblasting with 50 µm Al2O3 particles; SB-S: SB + silane; SB-S-A: SB-S + adhesive; SB-UA: SB + universal adhesive. Resin cement microcylinders (Ø = 0.96 mm; height = 1 mm) (RelyX Ultimate) were built upon the PICN surface after roughness and contact angle measurements. Next, microshear bonding tests (µSBS) were performed (0.5 mm/min) after water storage (37ºC, 90 days) and thermocycling (12,000 cycles; 5ºC-55ºC). Failure modes were observed under stereomicroscope. Bond strength data were analyzed by two-way ANOVA/Tukey's test and t-tests. Kruskal-Wallis/Dunn's tests were conducted for roughness and contact angle data (α = 0.05). Results: A rougher surface and lower contact angles were observed for Sandblasting. HF-S (18.54 ± 2.03 MPa), SB-S (19.00 ± 1.66 MPa) and SB-UA (18.07 ± 2.36 MPa) provided the highest bond strength values, followed by the other treated groups. The CTRL group resulted in lower bond strength (7.18 ± 2.34 MPa). Conclusion: Hydrofluoric acid etching followed by silane application and sandblasting followed by silane or universal adhesive are useful clinical steps to enhance bonding to PICN. Adhesive applications after HF etching have no advantages in bonding to PICN

Retention strength of ball-attachment titanium post for removable partial denture or overdenture

Aim: To evaluate the retention of an endodontic titanium postwith a spherical head for removable partial denture or overdentureattachment according to surface treatment type. Methods: Sixtyhealthy single-rooted teeth, sectioned at the enamel/cementumjunction, were treated endodontically and steadily fixed in theembedding acrylic resin. The titanium posts were subdivided intofour groups: control, no surface treatment (Ctrl); posts with macroretentivegrooves (MR); air abrasion of the post surface (AB); andposts with macro-retentive grooves and air abrasion of the postsurface (MR+AB). The posts were luted in the root canal usingself-adhesive dual resin cement. Pull-out testing was performedusing a universal testing machine until complete detachment wasachieved. After pull-out testing, the metallic posts were examinedunder an optical microscope and the failures were classifiedbased on the cement distribution pattern on the extracted posts:0, no cement left on the post (cement/post failure); 1, postsurface partially covered by adhered cement (post/cement anddentin/cement mixed failure); 2, post surface completely coveredby cement (dentin/cement failure). The retention data wereanalyzed by one-way ANOVA, Bonferroni­Dunn test (p<0.05)and Weibull analysis. Results: AB showed the highest retentionvalue (485.37±68.36), followed by MR+AB (355.80±118.47), MR(224.63±42.54) and Ctrl (113.12 ± 51.32). AB and MR showedthe highest Weibull moduli. Conclusions: The data indicatedthat air abrasion alone could significantly increase the retentionof titanium posts/attachments for use with overdentures orremovable partial denture

Lesões cervicais não cariosas: considerações etiológicas, clínicas e terapêuticas / Lesiones cervicales no cariosas: consideraciones etiológicas, clínicas y terapéuticas / Non-carious cervical injuries: etiological, clinical and therapeutic considerations

RESUMO Introdução: As lesões cervicais não cariosas são lesões dentárias, que apresentam etiologia multifatorial, sem o envolvimento de bactérias. Objetivo: Descrever as características clínicas, etiologia e tratamento das lesões cervicais não-cariosas. Métodos: Realizou-se uma revisão bibliográfica de estudos publicados nos últimos 5 anos (2014-2018) por meio da busca nas bases de dados: PubMED/Medline, Lilacs, Science Direct, SciELO (Scientific Eletronic Library) e Google Acadêmico. Para a pesquisa foram utilizados os seguintes descritores: "lesões cervicais não cariosas (non-carious cervical lesions)", "abrasão dentária (dental abrasion)", "erosão dentária (dental erosion)", "abfração dentária (dental abfraction)" e "atrição dentária (dental atrittion). Após criteriosa filtragem, foram selecionados 26 artigos e 2 livros para inclusão no estudo. Análise e integração das informações: As lesões cervicais não cariosas comumente classificadas em: abrasão, abfração, erosão e atrição. Essas lesões podem apresentar diversas formas, apesar de serem incluídas em uma classe genérica de denominação. São lesões que causam a perda gradativa dos tecidos mineralizados dentários, podendo trazer inúmeras consequências ao dente acometido. Conclusão: Para um correto diagnóstico e decisão de tratamento, essas lesões devem ser vistas sob seu aspecto etiológico multifatorial. Diversas possibilidades terapêuticas podem ser utilizadas no tratamento dessas lesões sendo necessário que o clínico conheça os principais fatores etiológicos e características clínicas que as diferenciem(AU)

RESUMEN Introducción: Las lesiones cervicales no cariosas son lesiones dentales, que presentan etiología multifactorial, sin la participación de bacterias. Objetivo: Describir las características clínicas, etiología y tratamiento de las lesiones cervicales no cariosas. Métodos: Se realizó una revisión bibliográfica de estudios publicados en los últimos 5 años (2014-2018) a través de la búsqueda en las bases de datos: PubMED / Medline, Lilacs, Science Direct, SciELO (Scientific Eletronic Library) y Google Académico. Para la investigación se utilizaron los siguientes descriptores: "lesiones cervicales no cariosas", "abrasión dental", "erosión dental", "abfracción dental" y " " atrición dental. Después de un cuidadoso filtrado, se seleccionaron 26 artículos y 2 libros para su inclusión en el estudio. Análisis e integración de las informaciones: Las lesiones cervicales no cariosas comúnmente clasificadas en: abrasión, abfración, erosión y atrición. Estas lesiones pueden presentar diversas formas, aunque se incluyen en una clase genérica de denominación. Son lesiones que causan la pérdida gradual de los tejidos mineralizados dentales, pudiendo traer innumerables consecuencias al diente acometido. Conclusiones: Para un correcto diagnóstico y decisión de tratamiento, estas lesiones deben ser vistas bajo su aspecto etiológico multifactorial. Diversas posibilidades terapéuticas pueden ser utilizadas en el tratamiento de esas lesiones, por lo que resulta necesario que el clínico conozca los principales factores etiológicos y características clínicas que las diferencien(AU)

ABSTRACT Introduction: Non-carious cervical lesions are dental lesions of a multifactorial etiology, without the involvement of bacteria. Objective: Describe the clinical characteristics, etiology and treatment of non-carious cervical lesions Methods: A bibliographic review was conducted of studies published in the last five years (2014-2018) by searching the databases PubMED / Medline, Lilacs, Science Direct, SciELO (Scientific Electronic Library) and Google Scholar. The following descriptors were used: "non-carious cervical lesions", "dental abrasion", "dental erosion", "dental abfraction" and "dental attrition. After careful filtering, 26 articles and two books were selected for inclusion in the study. Data analysis and integration: Non-carious cervical lesions are commonly classified as abrasion, abfraction, erosion and attrition. These lesions may present various forms, but they are all grouped in a single generic class. They are lesions that cause the gradual loss of mineralized dental tissue, which may bring countless consequences to the affected tooth. Conclusions: For a correct diagnosis and treatment decision, these lesions must be seen under their multifactorial etiological aspect. Various therapeutic possibilities may be used in the treatment of these lesions, and it is necessary for the clinician to know the main etiological factors and clinical characteristics that differentiate them(AU)

Influence of sandblasting distance on enamel and ceramic structure bond strength / Influência do jateamento na estrutura cerâmica e esmalte, alterando a distância na resistência de união

Objetive: The purpose of this study was to evaluate the influence of sandblasting distance on ceramic and enamelbond strength. Material & Methods: Sixtythird molars were selected, enamel surfaces were ground flat with wet 600 - 2000 grit aluminum oxide abrasive papers and polished with three, one, and one-fourth micrometer-grit diamond pastes. On hundred and twentylithium disilicate-based core ceramic discs (2 mm diameter; 1 mm thickness) were also obtained and further divided into 7 groups [Group C, no sandblasting, Group SB-E(5-10) enamel sandblasting - 5 and 10 mm of distance, Group SBC(5-10) ceramic sandblasting 5 mm and 10 mm of distance, Group SB-EC(5-10) enamel and ceramic sandblasting 5 mm and 10 mm of distance]. After treatments,shear and Atomic Force Microscopy (AFM) tests were performed.Data were analyzed by Statistic Tests of normality, one-way ANOVA and Tukey post-test (α: 0.05). Results: Group C presented the highestbond strength values(59.2 ±12.5), while group SB-E 5 mm showed the lowest values (21.7 ± 08.8) (p < 0.005). Conclusion: The use of sandblasting treatment of enamel surface at 5mm distance decreases the bonding strength to shear.

Objetivo: o objetivo do estudo foi avaliar influência do jateamento na estrutura cerâmica e esmalte sob resistência de união, mudando a distância. Materiais e Métodos: 60 terceiros molares, foram selecionados, superfícies de esmalte foram planificadas com lixa com grão 600 - 2000 lixas e polido com pastas de diamante de um grão -micrômetro. Obtidos 120 discos cerâmica em dissilicato de lítio de (2 mm de diâmetro e 1 mm de espessura), dividido em sete grupos [Grupo C, não jateamento, Grupo SB-E (5-10) esmalte jateamento 5 e 10 mm, Grupo SB -C (5-10) de jacto de areia cerâmica 5 mm e 10 mm, Grupo SB-CE (5-10) e esmalte cerâmico areação 5 milímetros e 10 mm], depois foi realizado o microcisalhamento e a microscopia de forca atômica (AFM), estatística como Teste de Normalidade , após análise de variância one-way e teste de Tukey (α: 0,05). Resultados: A força do grupo C apresentou maiores valores de resistência de união (59,2 ± 12,5), o grupo SB-E 5 mm (21,7 ± 08,8) (p < 0,005), o grupo SB-E10 (53,6 ± 14,3). Conclusão: o uso de jateamento tratamento da superfície do esmalte de 5 mm, de 20 s diminui a força de ligação de microcisalhamento.

Effectiveness of high speed instrument and air abrasion on different dental substrates

The aim of this study was to compare the effectiveness of high speed (HS) and air abrasion (AA) instruments on groups of teeth (deciduous, permanent, bovine), in terms of preparation time, topography and presence of smear layer. Each group consisted of 5 teeth that had their buccal/lingual surfaces prepared by using either HS or AA. All procedures were standardized and timed. The teeth were then sectioned and prepared for evaluation of both the topography and the presence of smear layer by scanning electron microscopy. As regards preparation time, HS yielded preparations 1.5 times quicker than AA did on the three types of dental substrates (Wilcoxon test, p < 0.05). In both techniques (Kruskal-Wallis Test, p < 0.05) the preparation time was influenced by the dental substrate, particularly in deciduous teeth (Mann-Whitney test with Bonferoni's correction, p < 0.017), which required a longer preparation time. In the descriptive analysis of the topography, no difference was found between the substrates. Nonetheless, the different instruments used determined distinctive topographies. Both techniques produced a smear layer (÷2 McNemar, p > 0.05) in all substrates, but with different formations. In conclusion, the HS instrument was found to be more rapid than the AA. No difference was found between the three dental substrates as regards both the topography and the presence of smear layer. The differences found in the present study were only in relation to the effects of each instrument used.

Micro-morphological changes prior to adhesive bonding: high-alumina and glassy-matrix ceramics

The aim of this study was to qualitatively demonstrate surface micro-morphological changes after the employment of different surface conditioning methods on high-alumina and glassy-matrix dental ceramics. Three disc-shaped high-alumina specimens (In-Ceram Alumina, INC) and 4 glassy-matrix ceramic specimens (Vitadur Alpha, V) (diameter: 5 mm and height: 5 mm) were manufactured. INC specimens were submitted to 3 different surface conditioning methods: INC1 - Polishing with silicon carbide papers (SiC); INC2 - Chairside air-borne particle abrasion (50 µm Al2O3); INC3 - Chairside silica coating (CoJet; 30 µm SiOx). Vitadur Alpha (V) specimens were subjected to 4 different surface conditioning methods: V1 - Polishing with SiC papers; V2 - HF acid etching; V3 - Chairside air-borne particle abrasion (50 µm Al2O3); V4 - Chairside silica coating (30 µm SiOx). Following completion of the surface conditioning methods, the specimens were analyzed using SEM. After polishing with SiC, the surfaces of V specimens remained relatively smooth while those of INC exhibited topographic irregularities. Chairside air-abrasion with either aluminum oxide or silica particles produced retentive patterns on both INC and V specimens, with smoother patterns observed after silica coating. V specimens etched with HF presented a highly porous surface. Chairside tribochemical silica coating resulted in smoother surfaces with particles embedded on the surface even after air-blasting. Surface conditioning using air-borne particle abrasion with either 50 µm alumina or 30 µm silica particles exhibited qualitatively comparable rough surfaces for both INC and V. HF acid gel created the most micro-retentive surface for the glassy-matrix ceramic tested.

Controle da deposição de partículas de óxido de alumínio emitidas pelo sistema de abrasão a ar em consultório odontológico / Deposition control of aluminum oxide particles emitted by air-abrasion system indental office

Nesse estudo, avaliou-se a deposição de partículas de óxido de alumínio no campo operatório do cirurgião-dentista durante o emprego de um aparelho de abrasão a ar e sucção odontológica convencional parasucção do pó gerado. Um dispositivo metálico, simulando as posições de trabalho do cirurgião-dentista,possibilitou a captação das partículas durante o abrasionamento de dentes artificiais. Sugadores de salivaconvencional e modificado por funil foram empregados no sistema de sucção convencional da equipe odontológicacom a finalidade de captar o pó de óxido de alumínio. Os resultados foram expressos por meio deanálise estatística gráfica em função da quantidade em massa de partículas de óxido de alumínio obtida emfunção da distância e posição de trabalho do operador ao centro da boca de um manequim. A maior deposiçãode partículas ocorreu a 20 cm de distância do operador em relação ao centro da boca e na posição detrabalho 9h, quando se empregou o sugador de saliva convencional.

In this study the aluminum oxide particle deposition was evaluated in the operatory position of the dentistduring an air abrasion system application with conventional dental suction (CDS) for the aspiration of thedust. A metallic device, simulating the operatory position of the dentist was used to particles deposition duringthe abrasion of an artificial tooth. A conventional saliva ejector and a modified ejector by funnel-shapedattachment were used in conventional dental suction (CDS) to dust suction. The results were expressed inaluminum oxide particles mass in relation to the operatory position and distance from operator to the centerof the mouth. Statistical graphical analysis showed that the greatest particle deposition occurred at 20cm ofdistance from the operator to the center of the mouth, in the 9 o'clock operator position when the conventionalsaliva ejector was used.