Evaluation of physical-mechanical properties, antibacterial effect, and cytotoxicity of temporary restorative materials.

The objective of this study was to compare selective physical-mechanical properties, antibacterial effects and cytotoxicity of seven temporary restorative materials (TRM): five resin-based materials [Bioplic (B), Fill Magic Tempo (FM), Fermit inlay (F), Luxatemp LC (L) and Revotek LC (R)], and zinc oxide-eugenol cement (IRM) and glass ionomer cement (GIC) as the controls. Material and methods The physical-mechanical properties were evaluated by determining microleakage (ML), ultimate tensile strength (UTS) and Shore D hardness (SDH). In addition, the polymerization rate (Pr-1), depth of cure (DC), water sorption and solubility (WS/SL) were evaluated. The antimicrobial effects of the materials were assessed by biofilm accumulation of Streptococcus mutans (BT) and the direct contact test (DCT) by exposure to Enterococcus faecalis for 1 and 24 h, and cytotoxicity by MTT assay. The data were analyzed by ANOVA or Kruskall-Wallis tests, and a complementary post-hoc method (p<0.05). Results Group B, followed by FM and GIC had significantly lower percentages of microleakage in comparison with the other groups; Groups FM and L showed the highest WS, while Groups R and FM showed the significantly lowest SL values (p<0.05). Group R showed the statistically highest UTS mean and the lowest DC mean among all groups. Group F showed the lowest S. mutans biofilm accumulation (p=0.023). Only the Group L showed continued effect against E. faecalis after 1 h and 24 h in DCT. The L showed statistically lower viability cell when compared to the other groups. Conclusions These findings suggest the antibacterial effect of the temporary materials Fill Magic and Bioplic against S. mutans, while Luxatemp showed in vitro inhibition of S. mutans biofilm accumulation and E. faecalis growth. Regarding the cell viability test, Luxatemp was the most cytotoxic and Fill Magic was shown to be the least cytotoxic.

Evaluation of physical-mechanical properties, antibacterial effect, and cytotoxicity of temporary restorative materials

Abstract The objective of this study was to compare selective physical-mechanical properties, antibacterial effects and cytotoxicity of seven temporary restorative materials (TRM): five resin-based materials [Bioplic (B), Fill Magic Tempo (FM), Fermit inlay (F), Luxatemp LC (L) and Revotek LC (R)], and zinc oxide-eugenol cement (IRM) and glass ionomer cement (GIC) as the controls. Material and methods The physical-mechanical properties were evaluated by determining microleakage (ML), ultimate tensile strength (UTS) and Shore D hardness (SDH). In addition, the polymerization rate (Pr-1), depth of cure (DC), water sorption and solubility (WS/SL) were evaluated. The antimicrobial effects of the materials were assessed by biofilm accumulation of Streptococcus mutans (BT) and the direct contact test (DCT) by exposure to Enterococcus faecalis for 1 and 24 h, and cytotoxicity by MTT assay. The data were analyzed by ANOVA or Kruskall-Wallis tests, and a complementary post-hoc method (p<0.05). Results Group B, followed by FM and GIC had significantly lower percentages of microleakage in comparison with the other groups; Groups FM and L showed the highest WS, while Groups R and FM showed the significantly lowest SL values (p<0.05). Group R showed the statistically highest UTS mean and the lowest DC mean among all groups. Group F showed the lowest S. mutans biofilm accumulation (p=0.023). Only the Group L showed continued effect against E. faecalis after 1 h and 24 h in DCT. The L showed statistically lower viability cell when compared to the other groups. Conclusions These findings suggest the antibacterial effect of the temporary materials Fill Magic and Bioplic against S. mutans, while Luxatemp showed in vitro inhibition of S. mutans biofilm accumulation and E. faecalis growth. Regarding the cell viability test, Luxatemp was the most cytotoxic and Fill Magic was shown to be the least cytotoxic.

In vitro evaluation of the minimum bactericidal concentrations of different root-end filling materials.

AIM: The aim of this study was to evaluate the minimum bactericidal concentrations (MBC) of root-end filling materials ProRoot MTA, MTA Angelus and IRM. MATERIALS AND METHODS: Macrodilution broth method was used. Microorganisms used were: Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212) and Streptococcus mutans. Serial two-fold dilutions of root-end filling samples were prepared in macrodilution tubes with concentrations ranging from 1/2 to 1/512. The samples dilutions were incubated for 24 hours. After incubation, 0.1 ml of diluted culture was inoculated onto the surface of supplemented sheep blood agar (Merck, Germany) and all plates were incubated at 37°C in aerobic condition for 24 hours. The MBC was defined as the lowest concentration of root-end filling samples where no growth was recorded. RESULTS: MBC of both mineral trioxide aggregate (MTA) products against S. aureus were recorded as 15.62 mg/ml and for IRM 31.25 mg/ml MBC for both MTA groups against E. faecalis were recorded as 31.25 mg/ml and for IRM 62.5 mg/ml. MBC of all root-end filling samples against S. mutans were recorded as 62.5 mg/ml. CONCLUSION: All tested root-end filling materials showed acceptable MBC against S. aureus and E. faecalis. CLINICAL SIGNIFICANCE: All tested materials can be used safely for filling of a root-end cavity.

Estudio de cesión de cefalosporinas incluidas en cementos oseos acrílicos / Release assay of cephalosporyns included in acrylic bone cements

El progresivo aumento de la esperanza de vida ha originado un notable incremento de las patologías degenerativas óseas que requieren implatación de prótesis. Estas intervenciones quirúrgicas conllevan en ocasiones serias complicaciones entre las que cabe destacar las infecciones bacterianas. La gentamicina es el agente antimicrobiano de elección incluido en los cementos acrílicos para la prevención de dichas osteomielitis. Sin embargo, debido a la creciente aparición de cepas bacterianas resistentes a la gentamicina, en este trabajo se propone la utilización de terapia local antibacteriana con otros antibióticos del grupo de las cefalosporinas como son la ceftazidima y la cefotaxima: En el presente estudio, se validan los métodos analíticos utilizados para la cuantificación de las cefalosporinas, que se basan en la formación de complejos coloreados tras la reacción de la ceftazidima o cefotaxima con el cloruro de paladio como reactivo y la posterior determinación espectrofotométrica UV-Vis de los mismos a las longitudes de onda de 354 y 280 nm respectivamente. Posteriormente, se ha realizado un estudio de cesión "in vitro"de estos antibióticos tras su inclusión en cementos óseos acrílicos de polimetilmetacrilato (PMMA) (AU)

[Comparative studies on the ingrowth behavior and the bone adhesion of various implant materials. An animal experiment]. / Vergleichende Untersuchungen über das Anwachsverhalten und die Knochenhaftung verschiedener Implantatwerkstoffe. Eine tierexperimentelle Untersuchung.

Each of 36 mongrel dogs received implants of the following six materials: methyl methacrylate, carbon fibre composite, aluminium oxide-ceramic, titanium alloy, pure titanium and hydroxylapatite (HA). Test rods 7 mm in diameter were used to perform a push-out test, and discs with a diameter of 25 mm and a thickness of 5 mm were used for a plane traction test. The animals got a fluorochrome labelling and were harvested 8 weeks after operation. The results of the push-out test were a stability of 3.6 N/mm2 for HA and very low values for all the other materials, while the plane tension test showed a stability of 1.6 N/mm2 for the HA discs and values that were not even measurable for all the other materials. The interface of HA and the bone could not be separated by mechanical forces; usually the bone or the ceramic material fractured beneath the interface, so that the real stability of the interface must be rated very high. Light and fluorescence microscopy revealed a close bone connection for HA and only partial connections for the other materials. HA-coated materials may have a future in orthopaedics surgery.

A study of intrusion characteristics of low viscosity cement Simplex-P and Palacos cements in a bovine cancellous bone model.

Aseptic loosening is the most common long-term complication of cemented total hip arthroplasties (THA). The functional longevity of these implants depends on the bone-cement interface. The influence of cement injection pressure, type of cement, ambient temperature, chilling of the monomer, and centrifugation of cement-on-cement intrusion depth was investigated in specimens of bovine cancellous bone. In order to validate the bovine model for comparative purposes relative to use in man, a linear relationship between human and bovine cancellous bone was first demonstrated for various porosities and cement intrusion depth. Three cements (Low Viscosity Cement [LVC], Simplex-P, and Palacos) were intruded at three different pressures (20, 40, and 60 PSI) at the same ambient temperature and relative humidity into commercially prepared plugs of bovine cancellous bone. Cement intrusion depth was proportional to injection pressure for all three cements, but was significantly different for each cement at a given pressure. At 20, 40, and 60 PSI, Palacos had a cement intrusion depth of 1.4, 2.4, and 2.8 mm respectively, while the figures for Simplex-P were 2.2, 4.2, and 5.0 mm, and for LVC were 8.0, 12.0, and 14.6 mm. Ambient temperature had an inverse relationship with cement intrusion depth for all three cements given the same experimental conditions. Chilling the monomer increased the intrusion of Simplex-P to 5.8, 8.2, and 12.7 mm at 20, 40, and 60 PSI injection pressure respectively. Simplex-P intrusion depth was not modified by cement centrifugation at any of the three injection pressures tested.(ABSTRACT TRUNCATED AT 250 WORDS)

[Adhesion of the vitreous body to cured polymers]. / Issledovanie adgezii steklovidnogo tela na otverzhdennykh polimerakh.

The adhesive activity of several polymers as regard to vitreous body (VB) was examined by drying out the vitreous body on the surface of the materials under study. 3 types of polymers were compared with glass (silicon, polyurethan, polymethylmetacrilate). According to the reduction in adhesive activity as regard to VB the substances were ranged from silicon to glass. The authors believe that the mechanism of VB adhesion to polymers is linked to the absorption of gialuronic acid on their surface, which is part of VB. The above method is suggested for the selection of polymers used in the manufacturing of intraocular lenses.

In vivo versus in vitro polymerization of acrylic bone cement: effect on material properties.

Flexural strength and molecular weight of polymethylmethacrylate bone cement were determined for cement polymerized in vivo in a canine total hip replacement and cement from the same batch polymerized in vitro. Both in vivo and in vitro samples showed a slight increase in flexural strength and modulus at 2 weeks, followed by a nearly equivalent decline at 8 weeks. In vitro and in vivo samples exhibit a comparable stress to failure, but the in vivo samples show a significantly increased strain and decreased modulus. Cement from the proximal region of the prosthesis has significantly decreased flexural strength, lower modulus, and lower molecular weight than cement from the distal region and plug, suggesting that failures in the proximal region of a prosthesis may be due to inferior physical and mechanical properties of the bone cement in that region.

Protection induced by inactivated influenza virus vaccines with polymethylmethacrylate adjuvants.

Nanocapsules from a copolymer of polymethylmethacrylate and polyacrylamide were tested for adjuvant activity in mouse protection experiments with inactivated influenza virus as antigen. Viruses were either adsorbed on the capsules after polymerization or added to the monomers and incorporated by copolymerization after X-ray initiation. Both preparations showed enhanced immunity as compared to fluid vaccine, if the adjuvant content was 1%. The adjuvant effect was comparable to that caused by the mineral adjuvant Al(OH)3. After dilution of the polymer the adjuvant effect was lost. Such synthetic polymers at suitable concentrations could serve as alternatives to mineral adjuvants.