Levantamento do assoalho do seio maxilar – aspectos clínicos e de imagem / Maxillary sinus floor lifting – clinical and imaging aspects

Este artigo demonstra os recursos de imagens que contribuem para um diagnóstico e planejamento eficazes na execução previsível do procedimento cirúrgico de levantamento de assoalho de seio maxilar (ESM), um problema comumente encontrado na reabilitação posterior de maxila, limitando a instalação de implantes de comprimento médio (10 mm). Os procedimentos de elevação do assoalho do seio maxilar (ESM) são uma opção para a resolução desse problema. Atualmente, duas principais técnicas são utilizadas para ESM: a técnica atraumática, com a utilização de osteótomos e instalação simultânea de implantes; e a técnica de janela lateral, com ou sem instalação simultânea de implantes. A decisão da técnica a ser realizada é baseada na avaliação da quantidade óssea e na possibilidade de estabilidade primária dos implantes. Esse passo é realizado com o auxílio de exames de imagens bi e tridimensionais. Nos casos em que é necessária a utilização de enxertos, o osso autógeno é considerado o padrão-ouro. No entanto, a literatura também apresenta casos de sucesso utilizando substitutos ósseos e combinações com osso autógeno. Apesar da técnica já estar bem desenvolvida, algumas complicações podem ocorrer em procedimentos de ESM, como a perfuração da membrana sinusal, hemorragias, estabilidade primária do implante insuficiente, deslocamento do enxerto dentro do seio maxilar e exposição ou lesões de nervos...

This article highlights the imaging resources contributing to effective diagnosis and planning for elevation of the maxillary sinus floor (ESM), a common issue at the posterior region which prevents implant placement of 10 mm in length. ESM procedures can overcome this situation. Nowadays, two main techniques are available for ESM: the atraumatic technique, with the use of osteotomes and immediate implant placement, and the lateral window technique, with/without implant placement. Decisions are based on available bone quantity and primary implant stability. Also, bi- and three-dimensional imaging techniques are valuable tool in this process. When necessary, the autogenous bone is still the gold standard. However, there are reports of success with bone substitutes and combinations with autogenous material. Although well-developed, some complications occur with ESM procedures, as well as membrane perforation, hemorrhage, lack of primary implant stability, and graft displacement inside the maxillary sinus, exposure, and nerve damage...

Effect of fluoride solutions on color and surface roughness of dental composites / Efeito de soluções fluoretadas sobre a cor e rugosidade de superfície de compósitos odontológicos

Objective: The aim of this study was to assess the ac-tion of fluoride solutions on color stability (?E) and sur-face roughness (Ra) of composites (HeliomolarTM, 4 Sea-sonsTM, Tetric N-CeramTM, SR AdoroTM). Materials and method: A Teflon matrix (12x2 mm) was used to fabri-cate 24 test specimens for each composite. The samples were separated into 4 groups (n=6), according to the immersion solution: distilled water (control), acidulated phosphate fluoride (1.23%), neutral sodium fluoride gel (2%), and solution of sodium fluoride (0.05%). Color (Spectrophotometer PCB 6807) and roughness (Surf-corder SE 1700) readings were performed before and after immersion into the solutions. Results: Composites presented color alteration within clinically acceptable limits (?E<3.3), increasing according to the periods of immersion. Regarding roughness, it was observed that Ra values were lower than the critical limit to promote increase in dental biofilm retention (Ra>0.2 µm). Con-clusions: Color and surface roughness alteration of the different composites was clinically acceptable after im-mersion in all fluoride solutions and in all periods.

Effect of artificial accelerated aging on the optical properties and monomeric conversion of composites used after expiration date.

This study sought to evaluate how artificial accelerated aging (AAA) affected color stability (ΔE), opacity (ΔOP), and degree of conversion (DOC) for 3 composite materials (Tetric Ceram, Tetric Ceram HB, and Tetric Flow) used both 180 days before and 180 days after their expiration dates. To evaluate the materials' optical properties, 10 specimens of each composite-5 prior to expiration and 5 after the materials' expiration date-were made in a teflon matrix. After polishing, the specimens were submitted to initial color and opacity readings and submitted to AAA for 384 hours; at that point, new readings were taken to determine ΔE and ΔOP. To evaluate monomeric conversion evaluation, 6 specimens from each composite and expiration date-3 prior to AAA and 3 after-were submitted to DOC analysis. Results of the 2-way ANOVA and Bonferroni's tests (P < 0.05) demonstrated that all composites had ΔE values above the clinically acceptable level (ΔE ≥ 3.3). When expiration dates were compared, only Tetric Flow showed a statistically significant difference (P < 0.05). Regardless of the expiration date, ΔOP values for all composites increased after AAA, but not significantly (P > 0.05). The expired Tetric Flow had the highest DOC values (71.42% ± 4.21) before AAA, significantly different than that of the other composites (P > 0.05). It was concluded that both expiration date and AAA affected the properties of the composites tested.

Color stability of experimental composites containing different photoinitiators.

OBJECTIVES: To evaluate the color stability (ΔE) of experimental composites containing different photoinitiators when submitted to accelerated artificial ageing (AAA). MATERIAL AND METHODS: Thirty test specimens were made in a Teflon matrix (8mm×2mm), using an experimental composite (n=10) with the same monomer composition and particle size, but varying photoinitiator used: Group CQ (0.4% Camphorquinone), Group PPD (0.4% 1-Phenyl-1,2 Propanodione) and Group CQ+PPD (0.2% CQ+0.2% PPD). The samples were light activated (QTH - Ultralux - Dabi Atlante - 40s) and polished before performing the initial color readouts (EasyShade - Vita). Next, they were submitted to AAA for 300h, after which final color readouts were made. RESULTS: The results (1-way ANOVA - Tukey - p<0.05) demonstrated that all the groups presented color alteration above the clinically acceptable level (ΔE≥3.3), however, with no statistically significant difference among them (p>0.05). Analysis of Δb demonstrated increase in the values of this coordinate, indicating yellowing in all groups. CONCLUSIONS: It was concluded that the type of photoinitiator, which presented a tendency towards yellowing, did not interfere in the color stability of composites submitted to AAA. CLINICAL SIGNIFICANCE: Alternative photoinitiators have been extensively studied since Camphorquinone presents a yellowish color, which compromises the aesthetic performance of composites, especially the lighter-shade ones.

Color stability, opacity and degree of conversion of pre-heated composites.

OBJECTIVES: To assess color stability and opacity associated with the degree of conversion of a pre-heated nanohybrid composite (Tetric N-Ceram, Ivoclar/Vivadent, Schaan, Liechtenstein). METHODS: Twenty-seven specimens were prepared (n=9) using a Teflon matrix following storage of compules containing the composite at temperatures of 8°C, 25°C or 60°C. After photoactivation and polishing, baseline readings of six specimens were taken regarding their color and opacity (Spectrophotometer PCB 6807, Byk Gardner, Geretsried, Germany). Then, the specimens were submitted to artificial ageing for 384 h (C-UV, Adexim Comexim, São Paulo, SP, Brazil), after which the final readings were taken. Three specimens for each temperature were submitted to analysis of degree of conversion (Nicolet 380, Thermo Scientific, Waltham, MA, USA). The results were analysed by 1-way ANOVA/Tukey (p<0.05). RESULTS: There was no significant difference in color stability and opacity variation amongst the temperatures evaluated. The composite pre-heated at 60°C had a higher degree of conversion (65.13%), with statistically significant difference compared to the other temperatures (p<0.05). CONCLUSIONS: Composite pre-heating does not promote changes in the optical properties, despite the increase in the degree of conversion.

Effect of staining solutions and repolishing on color stability of direct composites.

OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick) were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE) and high-density hybrid (Surefil; Dentsply) composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE). Color of the specimens was measured according to the CIE L*a*b* system in a reflection spectrophotometer (PCB 6807; BYK Gardner). After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control), G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE) between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically significant difference (ANOVA, Tukey's test; p>0.05) among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3) than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3), but remained significantly higher than those of the other groups. CONCLUSIONS: No significant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable ΔE values.

Colour stability, opacity and cross-link density of composites submitted to accelerated artificial aging.

The study evaluated the influence of accelerated artificial aging on colour stability, opacity and cross-link density of resin-based composites (RBCs). Seven specimens were obtained of five RBCs (Heliomolar, 4 Seasons, Tetric Evo Ceram, SR Adoro), which were submitted to colour stability and opacity analysis and cross-link density evaluation. All tests were performed before and after aging. After statistical analysis (one-way ANOVA; Tukey; p<0.05), it was observed that QuiXfil and SR Adoro presented colour alteration values above those that are clinically acceptable (deltaE=5.77 and 4.34 respectively) and the variation in opacity was lowest for SR Adoro. There was an increase in the cross-link density of all studied materials after aging.

Influence of artificial accelerated aging on dimensional stability of acrylic resins submitted to different storage protocols.

PURPOSE: The aim of this study was to evaluate the influence of artificial accelerated aging on dimensional stability of two types of acrylic resins (thermally and chemically activated) submitted to different protocols of storage. MATERIALS AND METHODS: One hundred specimens were made using a Teflon matrix (1.5 cm x 0.5 mm) with four imprint marks, following the lost-wax casting method. The specimens were divided into ten groups, according to the type of acrylic resin, aging procedure, and storage protocol (30 days). GI: acrylic resins thermally activated, aging, storage in artificial saliva for 16 hours, distilled water for 8 hours; GII: thermal, aging, artificial saliva for 16 hours, dry for 8 hours; GIII: thermal, no aging, artificial saliva for 16 hours, distilled water for 8 hours, GIV: thermal, no aging, artificial saliva for 16 hours, dry for 8 hours; GV: acrylic resins chemically activated, aging, artificial saliva for 16 hours, distilled water for 8 hours; GVI: chemical, aging, artificial saliva for 16 hours, dry for 8 hours; GVII: chemical, no aging, artificial saliva for 16 hours, distilled water for 8 hours; GVIII: chemical, no aging, artificial saliva for 16 hours, dry for 8 hours GIX: thermal, dry for 24 hours; and GX: chemical, dry for 24 hours. All specimens were photographed before and after treatment, and the images were evaluated by software (UTHSCSA - Image Tool) that made distance measurements between the marks in the specimens (mm), calculating the dimensional stability. Data were submitted to statistical analysis (two-way ANOVA, Tukey test, p= 0.05). RESULTS: Statistical analysis showed that the specimens submitted to storage in water presented the largest distance between both axes (major and minor), statistically different (p < 0.05) from control groups. CONCLUSIONS: All acrylic resins presented dimensional changes, and the artificial accelerated aging and storage period influenced these alterations.

Effect of staining solutions and repolishing on color stability of direct composites

OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick) were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE) and high-density hybrid (Surefil; Dentsply) composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE). Color of the specimens was measured according to the CIE L*a*b* system in a refection spectrophotometer (PCB 6807; BYK Gardner). After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control), G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE) between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically signifcant difference (ANOVA, Tukey's test; p>0.05) among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3) than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3), but remained signifcantly higher than those of the other groups. CONCLUSIONS: No signifcant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable ΔE values.

Análise das propriedades físico-mecânicas e biológicas dos cimentos resinosos / Analysis of the physical-mechanical and biological properties of the resinous cements

A procura cada vez maior por tratamentos restauradores estéticos e a eficiência de união entre o dente e o material restaurador proporcionam o desenvolvimento de inúmeras marcas comerciais de cimentos resinosos. O objetivo deste estudo foi realizar uma análise crítica sobre as propriedades físico-mecânicas e biológicas de diversos sistemas de cimentos resinosos, comparando-os entre si e também com os outros sistemas de cimentos não-resinosos; com intuito de auxiliar os profissionais da Odontologia na correta seleção e indicação desses cimentos, o que poderá contribuir para um maior sucesso do tratamento protético.