Bulk and surface properties related to composite filler size

There are few studies that fully characterize the effect of the filler size on the surface, optical and mechanical properties of resin composites. AIM: To determine the influence of the filler size content on surface, optical and mechanical properties before and after accelerated aging. METHODS: Seven resin composites were investigated: Filtek Supreme® (3M/ESPE), Estelite Σ Quick® (Tokuyama), Evolu-X® (Dentsply), Esthet-X HD® (Dentsply), Opallis® (FGM), Herculite XRV Ultra® (Kerr) and Filtek Z250® (3M/ESPE). Elastic modulus (EM) and flexural strength (FS) were determined by three-point bending of specimens immersed or not in absolute ethanol for seven days. Roughness (Ra) and gloss (G.U.) analyses were determined before and after ethanol storage for seven days and CIELAB color change (ΔE*) was obtained with a spectrophotometer. Results were analyzed by two-way ANOVA (general linear model) for EM and FS, with repeated measures for roughness and gloss, and one-way ANOVA for ΔE*. All comparisons were performed by Tukey's test (5%). Pearsons' correlation test was performed to determine the correlation between EM, FS, roughness, gloss, and ΔE* with the mean filler sizes. RESULTS: Mechanical properties decreased for all materials when submitted to immersion in ethanol. Increasing filler size gradually increased EM, FS and roughness values; gloss values decreased and didn't significantly affects ΔE*. Nanofiller composites presented higher gloss values than the others. CONCLUSIONS: It was possible to determine that the average filler size is a good predictor just for FS and gloss retention.

Do new matrix formulations improve resin composite resistance to degradation processes?

The aim of this study was to determine the degradation resistance of three new formulations-silorane-, Ormocer- and dimer-acid-based materials-and compare them to the traditional dimethacrylate-based materials. One silorane- (Filtek P90, P90), one Ormocer- (Ceram-X, CX), one dimer-acid- (N'Durance, ND) and two dimethacrylate-based (Filtek P60, P60; Tetric Ceram, TC) materials were investigated. Water sorption (Wsp) and solubility (Wsl) were determined after the materials were immersed in water for 28 days. Knoop hardness (KH) was determined before and after 24 h immersion in pure ethanol. The flexural-strength (FS) was determined by the bending test after one-week storage in a dry environment or after one-week immersion in pure ethanol. Data were submitted to analysis of variance (ANOVA) and Tukey's test (95%). The three new formulations showed lower Wsp than the dimethacrylate-based formulation. CX (0.50 ± 0.17%) and ND (0.72 ± 0.19%) exhibited the lowest Wsp, whereas P90 (0.02 ± 0.03%) and P60 (0.04 ± 0.03%) showed the lowest Wsl. All resins showed reduced Knoop hardness number (KHN) after ethanol immersion. P60 presented the lowest decrease in KH value (19 ± 5%). TC (48 ± 3%) and P90 (39 ± 9%) showed the highest KHN decrease after ethanol storage. The FS of CX, ND and TC were affected by ethanol storage. The new formulations did not improve the degradation resistance, as compared with the traditional methacrylate-based materials.

Oronasal complications in patients after transsphenoidal hypophyseal surgery / Complicações oronasais em pacientes pós-abordagem hipofisária via transesfenoidal

Transsphenoidal surgery is the most commonly used surgical procedure to handle the hypophyseal region, sometimes associated with oronasal complications. MATERIAL AND METHODS/AIM: To evaluate prospectively (specific questionnaire, clinical evaluation) undiagnosed chronic oronasal complications in patients submitted to conventional transsphenoidal adenomectomy surgery, operated at different neurosurgery services more than 6 months ago. RESULTS: 49 patients were evaluated, 37/45 presented macroadenoma. 28,5 percent were submitted to more than one intervention, 2/5 transsphenoidally. Transsphenoidal approach 92.8 percent through sublabial route. No patient had spontaneous complaint. With the specific questionnaire 63.2 percent presented complaints. One patient presented an oronasal fistula, 1 stenosis of the nasal valve area with external nasal deformity. Rhinoscopy detected alterations in 77.5 percent, nasal endoscopy in 87.7 percent. Septal perforation was present in 10/12 patients with scabs and 2 with purulent secretion. All 4 patients submitted to 2 transsphenoidal approaches presented septal perforation and nasal synechiae. In the endonasal, synechiae (2), alteration in medium meatus (1) and stenosis of the nasal valve area (1) were observed. Only two patients presented normal evaluation. CONCLUSION: A high incidence of nasal complications after conventional transsphenoidal surgery observed through examination and not reported spontaneously point to the need of otorhinolaryngological investigation complemented by nasal endoscopy in patients submitted to procedures through this route.

A cirurgia transesfenoidal é o procedimento cirúrgico mais utilizado para abordagem da região hipofisária, sendo por vezes associada a complicações oronasais. MATERIAL E MÉTODOS/OBJETIVO: Estudo prospectivo, através de questionário específico e avaliação clínica complicações oronasais crônicas não-diagnosticadas, em pacientes submetidos à cirurgia transesfenoidal convencional em diferentes serviços de neurocirurgia há mais de 6 meses. RESULTADOS: 49 pacientes, 37/45 com macroadenoma. 14/49 submetidos a mais de uma intervenção, em 2/5 por via transesfenoidal. Abordagem transesfenoidal 92,8 por cento via sublabial. Nenhum apresentava queixa espontânea. Com o questionário específico, 63,2 por cento apresentaram queixas. Um apresentava fístula oronasal, outro, estenose da área de válvula nasal com deformidade nasal externa. A rinoscopia detectou alterações em 77,5 por cento e a endoscopia nasal em 87,7 por cento. Perfuração septal presente em 10/12 pacientes com crostas e 2 com secreção purulenta. Todos 4 pacientes submetidos a 2 abordagens transesfenoidais apresentaram perfuração do septo e sinéquias nasais. Nos casos com abordagem endonasal observaram-se sinéquias2, alteração em meato médio1 e estenose em área de válvula nasal1. Apenas 2 pacientes apresentaram avaliação normal. CONCLUSÃO: Alta incidência de complicações nasais após abordagem transesfenoidal convencional, observadas (exame) e não referidas espontaneamente indicam a necessidad de investigação otorrinolaringológica complementada com endoscopia nasal sistemática nestes pacientes.