Biofilm behavior on sulfonated poly(ether-ether-ketone) (sPEEK).

Poly(ether-ether-ketone) (PEEK) has also shown to be very attractive for incorporating therapeutic compounds thanks to a sulfonation process which modifies the material structure resulting in a sulfonated-PEEK (sPEEK). Concerning biomedical applications, the objective of this work was to evaluate the influence of different sulfonation degree of sPEEK on the biofilm growth. PEEK samples were functionalized by using sulphuric acid (98%) and then dissolved into dimethyl-sulfoxide. A dip coating technique was used to synthesize sPEEK thin films. The sulfonation degree of the materials was analyzed by FT-IR, H NMR, TG and IEC. The surfaces were characterized by scanning electron microscopy, profilometry and contact angle analyses. Subsequently, the biofilm formation on sulfonated-PEEK based on Streptococcus mutans and Enterococcus faecalis was measured by spectrophotometry, colony forming units (CFUmL-1) and SEM. Results obtained from thermal and chemical analyses showed an intensification in sulfonation degree for sPEEK at 2 and 2.5h. The E. faecalis or S. mutans biofilm growth revealed statistically significant differences (p<0.05) between 2 and 3h sulfonation groups. A significant decrease (p<0.05) in CFUmL-1 was recorded for S. mutans or E. faecalis biofilm grown on 2.5 or 3h sPEEK. Regarding the thermal-chemical and microbiologic analyses, the sulfonation degree of sPEEK ranging from 2 up to 3h was successful capable to decrease the biofilm growth. That revealed an alternative strategy to embed anti-biofilm and therapeutic compounds into PEEK avoiding infections in biomedical applications.

Chemical, microscopic, and microbiological analysis of a functionalized poly-ether-ether-ketone-embedding antibiofilm compounds.

Poly-ether-ether-ketone (PEEK) is currently introduced as an alternative material for orthopedic implants due to its biocompatibility and low elastic modulus compared to titanium. Also, a sulphonation treatment can functionalize PEEK to embed therapeutical substances. The objective of this work was to functionalize a PEEK film to incorporate novel lactam-based antibiofilms compounds. PEEK samples were functionalized by sulphuric acid treatment and then dissolved in dimethylsulfoxide, where lactams were added to be incorporated into the polymer. A dip-coating technique was used to synthesize a thin film on a glass-based substrate. The degree of sulfonation (DS) and the incorporation of lactams into sulphonated PEEK (sPEEK) were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and scanning electron microscopy. A DS of 65% was obtained and TGA curves confirmed the presence of SO3 H and lactams in the sPEEK structure. The growth of Streptococcus mutans biofilm decreased on sPEEK surface containing lactams when compared to sPEEK free of lactams. That indicated the antibiofilm activity of those compounds was maintained after incorporation into sPEEK. Planktonic growth analysis showed no long distant effects of sPEEK containing lactams, indicating that no systemic effects should be expected upon clinical uses of medical devices produced with lactam-treated sPEEK. Results revealed that inclusion of lactams into sPEEK represents a good alternative for the production of biomaterials resistant to bacterial accumulation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3015-3020, 2016.

A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline.

This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride (CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+ 10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2 months, E. faecalis penetration was analyzed along the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan-Meier method was used to analyze survival and the Logrank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statistically significant difference among the experimental groups (p=0.102). The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.

A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline / Avaliação laboratorial da infiltração bacteriana em plugs apicais de mta expostos ao tampão fosfato-salino

O presente estudo avaliou a influência da exposição do agregado de trióxido mineral (MTA) – com e sem cloreto decálcio (CaCl2) – ao tampão fosfato-salino (PBS) sobre a microinfiltração apical. Sessenta segmentos radiculares foram divididos em 4 grupos experimentais (n=15). As cavidades apicais foram preenchidas com MTA, com ou sem CaCl2, e os canais radiculares receberam uma bolinha de algodão umedecida ou PBS, como medicação intracanal: 1) MTA/bolinha de algodão umedecida; 2) MTA/PBS; 3) MTA+10%CaCl2/ bolinha de algodão umedecida; 4) MTA+10% CaCl2/PBS. Após 2 meses, a penetração de E. faecalis ao longo dos plugs apicais foi avaliada. As amostras foram observadas semanal -mente durante 70 dias e a infiltração detectada através da turbidez do meio em contato com os segmentos radiculares. Dentes pertencentes aos grupos controle (n=2) foram mantidos completamente impermeáveis ou sem plug apical. A análise de sobrevivência e a comparação das curvas foram realizadas por meio dos testes Kaplan-Meier e Log-rank (p<0.05), respectiva -mente. Todas as amostras do grupo controle positivo apresentaram evidência de infiltração dentro de 24h, enquanto nenhuma amostra do grupo controle negativo apresentou infiltração aolongo dos 70 dias. Não houve diferença significativa entre os grupos experimentais (p=0.102). O uso do PBS como medicação intracanal pode melhorar a capacidade de selamento do MTA,mas não é capaz de impedir a infiltração bacteriana. A adição de CaCl2 ao MTA não melhora sua capacidade de selamento.

This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride(CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2months, E. faecalis penetration was analyzed a long the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan–Meier method was used to analyze survival and the Log-rank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statisticall y significant difference among the experimental groups (p=0.102).The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.