Ketac Molar Easymix Research Articles

In Situ Surface Biodegradation of Restorative Materials

SUMMARY This study aimed to evaluate the surface characteristics of restorative materials (roughness, hardness, chemical changes by energy-dispersive spectroscopy [EDX], and scanning electron microscopy [SEM]) submitted to in situ biodegradation. Fifteen discs of each material (IPS e.max [EM], Filtek Supreme [FS], Vitremer [VI], Ketac Molar Easymix [KM], and Amalgam GS-80 [AM]) were fabricated in a metallic mold (4.0 mm × 1.5 mm). Roughness, hardness, SEM, and EDX were then evaluated. Fifteen healthy volunteers used a palatal device containing one disc of each restorative material for seven days. After the biodegradation, the roughness, hardness, SEM, and EDX were once again evaluated. Data obtained from the roughness and hardness evaluations were submitted to Kolmogorov-Smirnov and Tukey-Kramer tests (p<0.05). All esthetic restorative materials showed a significant increase in the roughness after biodegradation. Before biodegradation, significant differences in the hardness among the materials were seen: EM>AM>FS>KM>VI. After biodegradation, the hardness was significantly altered among the materials studied: EM>AM>FS=KM>VI, along with a significant increase in the hardness for AM, KM, and VI. SEM images indicated degradation on the surface of all materials, showing porosities, cracks, and roughness. Furthermore, after biodegradation, FS showed the presence of Cl, K, and Ca on the surface, while F was not present on the VI and KM surfaces. EM and AM did not have alterations in their chemical composition after biodegradation. It was concluded that the dental biofilm accumulation in situ on different restorative materials is a material-dependent parameter. Overall, all materials changed after biodegradation: esthetic restorative materials showed increased roughness, confirmed by SEM, and the ionomer materials and silver amalgam showed a significantly higher hardness. Finally, the initial chemical composition of the composite resin and ionomer materials evaluated was significantly altered by the action of the biofilm in situ.

Effect of polishing on the microleakage of three different restorative materials: an in vitro study.

The purpose of this in vitro study was to investigate the effect of polishing systems on the microleakage of three different restorative materials (Ketac Molar Easymix, Ketac N100 and Filtek P90). Class V cavities were prepared at the cemento-enamel junction of 60 freshly extracted premolars. The prepared teeth were randomly divided into three groups and restored with the three materials. The restored teeth were stored in distilled water at 37°C for 1 week. The restored teeth were then divided into two subgroups (polished and not polished) of 10. Finishing and polishing of the polished group was done using the Sof-Lex polishing system. Furthermore, all the restorations were subjected to dye penetration testing. Results showed that maximum microleakage was observed for the not polished group of Filtek P90 and least levels of microleakage were seen for the polished group of Ketac Molar Easymix. There was a significant difference seen when Ketac Molar Easymix was compared with Ketac N100 and Filtek P90 in terms of the extent of microleakage exhibited on polishing of the three materials; with the former exhibiting the least microleakage scores.

Addition of chlorhexidine gluconate to a glass ionomer cement: a study on mechanical, physical and antibacterial properties.

The objective of this work was to determine the effect of different concentrations of chlorhexidine digluconate (CHX) on setting time, surface hardness, maximum tensile bond strength and antibacterial activity of a glass ionomer cement (GIC). The material used as control was Ketac Molar Easymix GIC. CHX was incorporated into the GIC during its manipulation at concentrations of 0.5, 1.0 and 2.0%. Antimicrobial activity against S. mutans and L. acidophilus was evaluated by means of agar diffusion test. Tensile bond strength data were analyzed statistically using Analysis of variance and Tukey's test. Setting time, Vickers hardness and agar diffusion test were analyzed using Kruskal-Wallis and Mann-Whitney tests at a significance level of 5%. It was observed that adding CHX at concentrations of 1% and 2% increased significantly the setting time of the material (p=0.012 and p=0.003, respectively). There was no significant difference between control and 0.5% CHX groups regarding the setting time. Addition of 2% CHX decreased significantly the surface hardness in relation to the control group (p=0.009), followed by the 1% CHX group (p=0.009). The tensile bond strength of the material also decreased significantly after adding CHX at a concentration of 2% (p=0.001). Addition of CHX promoted formation of an inhibition halo in both bacterial strains for all concentrations. The results showed that the best option for clinical use of GIC with CHX is at 0.5% concentration, since antibacterial activity increased and the physical-mechanical properties remained unchanged.

An in vitro biocompatibility study of conventional and resin-modified glass ionomer cements.

To evaluate the biocompatibility of a glass-ionomer (GIC) and a resin-modified glass-ionomer cement (RM-GIC), cell viability was examined in a model of human gingival fibroblasts using morphological, biochemical, and ionic patterns by means of phase contrast microscopy, lactate dehydrogenase (LDH) release, and quantitative x-ray microanalysis (EPXMA). The GIC Ketac-Molar Easymix (3M ESPE) and the RM-GIC Vitrebond (3M ESPE) were compared in human gingival fibroblasts exposed to the cements for 72 h. As controls, fibroblasts cultured with DMEM culture medium (negative control) and with 1% triton × (positive control) were used. Light microscopic findings showed greater morphological alterations in cells exposed to RM-GIC than to GIC. The relative percentage of LDH released from the cells to the supernatant was significantly higher in RMGIC cultures than in the control. Quantitative x-ray microanalysis showed that cultures exposed to RM-GIC were characterized by an increase in intracellular Na and a decrease in intracellular Cl and K. These changes in ion composition were significant compared to control and GIC cultures. The three indicators of cellular biocompatibility after 72 h of exposure showed that RM-GIC led to more marked alterations than GIC in human gingival fibroblasts.

The atraumatic restorative treatment (ART) strategy in Mexico: two-years follow up of ART sealants and restorations

BackgroundThe massive use of preventive measures in Mexico has resulted in a large decline in dental caries over the past two decades. There does however remain a largely unmet need for restorative treatment. This paper describes the steps leading up to the adoption of a strategy, as part of general health policy, to use Atraumatic Restorative Treatment (ART) within the Mexican public health service as a means of addressing this. The objective was to evaluate ART restorations and sealants placed in primary and permanent teeth in schoolchildren from deprived areas over a period of 2 years.Methods18 Dentists from 13 municipalities in 6 states with the lowest human development index treated 304, 6- to 13-year-old schoolchildren with ART sealants and ART restorations (single-surfaces) on the school compounds. Ketac Molar Easymix was the filling material used. ART procedures were evaluated according to the ART assessment criteria after 1 and 2 years, by 7 calibrated evaluators. Survival rates were estimated, using the PHREG Model with frailty correction.ResultsThe 2-year cumulative survival rates of fully and partially retained ART sealants were 73.1% (primary teeth) and 48.8% (permanent teeth). The dentine carious lesion failure rates of ART sealants in primary and permanent teeth over the 2-year period were 0% and 2.5%, respectively. The 2-year cumulative survival rates of single-surface ART restorations in primary and permanent teeth were 74% and 80.9%, respectively. Secondary carious lesion development occurred in 6 restored primary teeth (2.1%) and in one restored permanent tooth (1.3%). All restorations placed in primary teeth in one state survived, whilst those in one of the 5 remaining states failed statistically significantly more than those in the other 4.ConclusionsThe ART procedures were of substantial quality and had prevented to a large extent the development of new dentine carious lesions in these children from socio-economically deprived areas.

Inorganic elemental analysis and identification of residual monomers released from different glass ionomer cements in cell culture medium

INTRODUCTION: Glass ionomer cements (GICs) release inorganic elements and organic residual monomers with the potential for deleterious effects on pulp cells. OBJECTIVE: To identify and quantify inorganic elements present in different GICs and released components from these materials in cell culture medium. MATERIAL AND METHOD: Samples of two resin-modified GICs for base/liner (Vitrebond and Fuji Lining LC), two resin-modified restorative GICs (Vitremer and Fuji II LC) and two conventional restorative GICs (Ketac Fil Plus and Ketac Molar Easymix) were prepared and analyzed by Energy-Dispersive X-Ray Fluorescence Spectrometry (EDXRF). Extracts of these materials were obtained by immersion of each sample in separate containers of DMEM for 24 h (total surface-liquid ratio = 45.7 mm²/mL). The extracts were analyzed by EDXRF and Gas Chromatography-Mass Spectrometry (GC-MS). RESULT: Higher percentages of strontium, silicon and aluminum were identified in Vitrebond, Vitremer, Fuji Lining LC, Fuji II LC, and Ketac Fil Plus, while zinc was detected only in Vitrebond. Ketac Molar Easymix presented a greater atomic composition of lanthanum, calcium, aluminum and silicon. Strontium was detected in the extracts from all materials except Ketac Molar Easymix; calcium was present in extracts from Ketac Fil Plus; zinc only in Vitrebond; and silicon in Fuji II LC extract. The analysis by GC-MS detected 2-hydroxyethyl-methacrylate (HEMA) in the extracts from all resin-modified GICs, and iodine benzene was detected only in the Vitrebond extract. CONCLUSION: Of the GICs sampled, Vitrebond released the highest number of components with cytotoxic potential.

Mechanical performance of encapsulated restorative glass-ionomer cements for use with Atraumatic Restorative Treatment (ART)

The Atraumatic Restorative Treatment (ART) approach was suggested to be a suitable method to treat enamel and dentine carious lesions in patients with disabilities. The use of a restorative glass-ionomer with optimal mechanical properties is, therefore, very important.Objective:To test the null-hypotheses that no difference in diametral tensile, compressive and flexural strengths exists between: (1) The EQUIA system and (2) The Chemfil Rock (encapsulated glass-ionomers; test materials) and the Fuji 9 Gold Label and the Ketac Molar Easymix (hand-mixed conventional glass-ionomers; control materials); (3) The EQUIA system and Chemfil Rock. Material and Methods:Specimens for testing flexural (n=240) and diametral tensile (n=80) strengths were prepared according to standardized specifications; the compressive strength (n=80) was measured using a tooth-model of a class II ART restoration. ANOVA and Tukey B tests were used to test for significant differences between dependent and independent variables. Results:The EQUIA system and Chemfil Rock had significantly higher mean scores for all the three strength variables than the Fuji 9 Gold Label and Ketac Molar Easymix (α=0.05). The EQUIA system had significant higher mean scores for diametral tensile and flexural strengths than the Chemfil Rock (α=0.05). Conclusion:The two encapsulated high-viscosity glass-ionomers had significantly higher test values for diametral tensile, flexural and compressive strengths than the commonly used hand-mixed high-viscosity glass-ionomers.

Resistência à tração diametral de cimentos de ionômero de vidro submetidos à aplicação de ondas de ultrassom

INTRODUÇÃO: O cimento de ionômero de vidro é um material odontológico que apresenta limitações de uso devido às suas propriedades mecânicas, como baixa resistência ao desgaste, microdureza, compressão e tração diametral. Com base nisso, este estudo investigou o efeito da excitação ultrassônica sobre o CIV, em diferentes tempos de aplicação, por meio da resistência à tração diametral. MATERIAL E MÉTODO: Os materiais utilizados foram o Ketac Molar Easymix (KME) e o Ketac Cem Easymix (KCE). Foram confeccionados 10 corpos de prova para cada condição estudada: grupo controle, e os grupos que receberam aplicação de ultrassom por 15s, 30s e 45s, para ambos materiais. A excitação ultrassônica foi aplicada durante a reação de presa inicial do CIV, logo após sua inserção na matriz de silicone. Os valores de resistência à tração diametral foram analisados pelo teste Shapiro Wilk e Anova (α = 0.05). RESULTADO: A aplicação de excitação ultrassônica não apresentou efeito estatisticamente significante na resistência à tração diametral dos materiais testados, independente do tempo de aplicação (p &gt; 0,05). O KME apresentou resistência estatisticamente maior que o KCE (p = 0,023). CONCLUSÃO: A utilização das ondas ultrassônicas não influenciou na resistência à tração diametral dos CIV testados independentemente do seu tempo de aplicação.

Biaxial Flexural Strength of High-Viscosity Glass-Ionomer Cements Heat-Cured with an LED Lamp during Setting

Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS) between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n = 30): without heating (Group 1), heated with LED lamp of 1400 mW/cm2 for 30 s while setting (Group 2), and heated with LED lamp of 1400 mW/cm2 for 60 s while setting (Group 3). Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α = 0.05). Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm2 during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times.

A preliminary clinical trial using flowable glass-ionomer cement as a liner in proximal-ART restorations: The operator effect

Objectives: This in vivo study was carried out to assess the influence of the operator experience on the survival rate of proximal-ART restorations using a two-layer technique to insert the glass-ionomer cement (GIC). Study Design: Forty five proximal cavities in primary molars were restored in a school setting according to the ART technique. The cavities were restored by two operators with Ketac Molar Easymix, and received a flowable layer of GIC prior to a second GIC layer with a regular consistency. The operators had different clinical experiences with ART (no experience or two years of experience), but both completed a one-week training to perform the restorations and the GIC mixing in this study. Results: After a 12-month follow-up, 74% of the restorations survived; the main reason for failure was bulk fracture or total loss of the restoration.There was no operator influence (log-rank test p=0.2) Conclusion: The results encourage future well designed controlled clinical trials using the two-layer technique for insertion of GIC in proximal-ART restorations, after training the operators. Key words:Atraumatic Restorative Treatment (ART), Glass-ionomer, proximal restorations.

Use of glass ionomer cement containing antibiotics to seal off infected dentin: a randomized clinical trial

Dental materials with antibacterial properties can prevent the harmful effects caused by oral cariogenic bacteria. This double-blind controlled clinical trial evaluated the performance of a glass ionomer cement (GIC) added with antibiotics for sealing infected dentin in atraumatic restorations of primary molars. The study enrolled 45 children (45 teeth) between 5 and 8 years of age, of both genders, divided into two groups: GC (n=22), where cavities were lined with a conventional GIC (Vidrion F) and GA (n=23), with cavities lined with Vidrion F added with 1% each of metronidazole, ciprofloxacin and cefaclor antibiotic. Both groups were restored with Ketac Molar Easymix. Molars with carious lesions on the inner half of dentin without clinical or radiographic pulp damage were selected. Patients were evaluated clinically (pain, fistulas or mobility) and radiographically (area of caries, periapical region and furcation) after 1, 3, 6 and 12 months. For statistical analysis, chi-squared or Fisher's exact tests were used with a 5% significance level. GA (82.6-95.7%) had better results than GC (12.5-36.4%) in all evaluations (p<0.05) and the difference in the success rate was 46.2-72.5% higher for GA. The use of the antibiotic-containing GIC liner on infected dentin proved satisfactory when applied in deciduous teeth.

Influences of the insertion method in glass ionomer cement porosity

The aim of this study was to evaluate the presence of porosities inside the glass ionomer cement (GIC) after different techniques of material insertion. Specimens were prepared with high-viscosity GIC Ketac Molar Easymix and divided into three groups according to the insertion method: spatula (PI), Centrix injector (CI), and low-cost syringe (LCS). The specimens were fractured and observed with scanning electronic microscopy to quantitatively evaluate porosity inside the material using Image J Software. Statistical analysis, ANOVA application, and Tukey test to significance level of 5%, revealed that there was no statistical difference between the groups. Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs.

Effect of Ultrasonic Excitation on the Microtensile Bond Strength of Glass Ionomer Cements to Dentin After Different Water Storage Times

The application of ultrasound waves on glass ionomer cement (GIC) surface can accelerate the early setting reaction and improve the mechanical properties of the material, resulting in higher resistance to masticatory forces within a short period of time and thus increasing the clinical longevity of the GIC restoration. In this study, the microtensile bond strength (μTBS) of two high-viscosity GICs (Fuji IX GP and Ketac Molar Easymix) and one resin-modified GIC (RMGIC-Vitremer) to dentin was tested after ultrasonic excitation and water storage. GIC blocks were built up on coronal dentin either receiving or not receiving a 30-s ultrasound application during the material initial setting. After storage in water for either 24 h or 30 d, beam-shaped specimens with a cross-sectional area of approximately 1.0 mm 2 were cut perpendicular to GIC/dentin interface and tested to failure. At 24 h, the ultrasonically set Ketac Molar had significantly higher ( p < 0.05) μTBS than the cement set conventionally. Chemically set Ketac Molar presented significantly higher μTBS after the longer water storage ( p < 0.05). The RMGIC presented the highest μTBS regardless of ultrasonic excitation and storage period. In conclusion, ultrasound application to Ketac Molar improved its adhesion to dentin, particularly within the first 24 h after setting. Clinically, it seems that ultrasonic excitation can contribute to prevent retention loss of restoration at early stages of GIC setting reaction.

Evaluation of Microleakage of Various Restorative Materials: An in Vitro Study

Microleakage is the clinically detectable passage of bacteria, fluids, molecules or ions between a cavity wall and the restorative materials applied to it. The aim of this study was to evaluate and compare the microleakage of six restorative materials viz., GC Fuji II LC, Ketac Molar Easy Mix, Filtek Z350, Filtek P60, Durafill VS and Dyract Restorative. Sixty caries-free premolars were divided into six groups (n = 10) and standard Class I cavities were restored with six different materials. Observation for marginal leakage was done under Stereomicroscope at 10X and data collected was subjected to statistical analysis. Concluding from the study, the sealing ability in terms of microleakage can be summarized as: Self-cured GIC (Ketac Molar Easy Mix) < Compomer (Dyract) < Packable composite (Filtek P60) < Resin modified Glass ionomer cement (GC Fuji II LC) d” Microfilled composite (Durafill VS) < Nanocomposite (Filtek Z350).

Comparing MTA and Ketac Molar Easymix for Furcation Perforation Repair using a Volumetric Method

Aim: We compared the ability of mineral trioxide aggregate (MTA) and Ketac Molar Easymix (KM) to repair furcal perforations in extracted human molars, based on the volume of methylene blue dye penetration.&#x0D; Methodology: In total, 44 human mandibular molars were divided randomly into two (n = 20 each) experimental groups, with two teeth used as positive controls and two teeth without perforations used as negative controls. Group 1 was repaired with MTA and group 2 with Ketac Molar Easymix. The volumetric determination of dye penetration was based on the molecular characteristics of methylene blue. The standard area of a methylene blue particle is known and the surface area can be calculated. We converted the dye penetration area into a volume and performed quantitative analyses.&#x0D; Results: Volume measurement using the dye penetration method showed that KM resulted in more microleakage than MTA (p &lt; 0.05).&#x0D; Conclusions: Mineral trioxide aggregate resulted in significantly less dye leakage than Ketac Molar Easymix using a volumetric measurement method.&#x0D; &#x0D; How to cite this article: Kaya S, Ganidağlı Ayaz S, Doğan MS, Aydın H. Comparing MTA and Ketac Molar Easymix for furcation perforation repair using a volumetric method. Int Dent Res 2011;1:13-17.&#x0D;

Effect of green propolis addition to physical mechanical properties of glass ionomer cements

ObjectiveThis study investigated the mechanical properties of glass ionomer cements (GICs) combined with propolis as a natural antimicrobial substanceMaterial and MethodsTypified green propolis, as an ethanolic extract (EEP) or in the lyophilized form (powder), was incorporated to specimens of Ketac Fil Plus, ChemFlex and Ketac Molar Easymix GICs. For each test, 8 specimens of each material were prepared. For water sorption and solubility tests, specimens were subjected to dehydration, hydration and re-dehydration cycles until a constant mass was obtained for each step. Measurements were recorded using a digital balance of 10-4 g precision. For the diametral tensile strength test, specimens were tested in a universal test machine at 0.5 mm/min crosshead speed after 24 h storage in deionized water. Data were evaluated by one-way ANOVA and Tukey’s tests (p<0.05).ResultsThe addition of propolis to GIC clearly increased water sorption compared to pure material. Solubility was material-dependent and was not clearly evident. For the diametral tensile strength test, association with propolis altered negatively only Chemflex.ConclusionIt may be concluded that incorporation of propolis to GICs alters some properties in a material-dependent condition.

Radioactive Isotope Evaluation of Coronal Leakage after Endodontic Treatment in Teeth Restored with Three Different Intracoronal Restorative Materials: An in vitro Study

ABSTRACT The aim of this study was to compare and evaluate the coronal microleakage following endodontic treatment of teeth restored with three different intracoronal restorations using calcium-45 radioisotope and autoradiography. A total of 48 extracted human mandibular premolars with single canals were divided into three experimental groups of 16 specimens each. The teeth were sectioned horizontally at the cementoenamel junction and at the middle-third of the root, orifices and canals were enlarged with Gates Glidden bur and finished using K files, and obturated with gutta-percha cones using lateral condensation technique. 3 mm of gutta-percha were removed from the coronal part of the teeth to prepare a clean 3 mm deep cavity for the coronal restorative material. Group 1 consisted of teeth restored with Ketac Molar Easymix; group 2 with Miracle Mix and group 3 with Filtek Z350. The teeth were then thermocycled and tested for microleakage using calcium-45 radioisotope. The results were analyzed using Kruskal-Wallis test and Mann-Whitney test. Filtek Z350 exhibited the least leakage followed by Ketac Molar Easymix and Miracle Mix, and the microleakage among the three restorative materials was statistically significant.

Shear bond strengths of three glass ionomer cements to enamel and dentine

The shear bond strength of three glass ionomer cements (GIC) to enamel and dentine was evaluated. Sound permanent human molars (n=12) were grinded perpendicular to their axial axes, exposing smooth, flat enamel and dentine surfaces. The teeth were embedded in resin and conditioned with polyacrylic acid (25%; 10s). Twenty four specimens of each GIC: Fuji IX (FJ-GC), Ketac Molar Easymix (KM-3M ESPE) and Maxxion (MX-FGM) were prepared according to the Atraumatic Restorative Treatment (ART) (12 enamel and 12 dentine), in a bonding area of 4.91 mm² and immersed in water (37°C, 24h). The shear bond strength was tested in a universal testing machine. Non-parametric statistical tests (Friedman and post-hoc Wilcoxon Signed Ranks) were carried out (p=0.05). The mean (±sd) of shear bond strength (MPa), on enamel and dentine, were: KM (6.4±1.4 and 7.6±1.5), FJ (5.9±1.5 and 6.0±1.9) and MX (4.2±1.5 and 4.9±1.5), respectively. There was a statistically significant difference between the GICs in both groups: enamel (p=0.004) and dentine (p=0.002). The lowest shear bond value for enamel was with MX and the highest for dentine was KM (p<0.05). It is concluded that KM has the best adhesion to both enamel and dentine, followed by FJ and MX.

Effect of ultrasonic excitation on the porosity of glass ionomer cement: A scanning electron microscope evaluation

Ultrasonic excitation (US) was applied to glass ionomer cement (GIC) during early set time to increase the advantageous properties of this material. The aim of this in vitro study was to assess the inner porosity of GIC after US. A total of 16 specimens, for each material, were prepared from high-viscosity GIC Fuji IX GP, Ketac Molar, and Ketac Molar Easymix. Half of these specimens (n = 8) received 30 s of US during the initial cement setting. After completion of the material setting, specimens were fractured and observed by scanning electronic microscopy to quantitatively assay porosity inside the material using Image J software. Statistical data analysis revealed that US reduced the porosity for all tested materials (P ≤ 0.05). The following reductions (expressed in percentages) were achieved: Fuji IX--from 3.9% to 2.8%; Ketac Molar Easy Mix--from 4.4% to 2.6%, and Ketac Molar--from 2.4% to 1.6%. Under the tested conditions, US was an effective method for porosity reduction inside the material.

Cytotoxicity evaluation of seven different resin based restorative materials: in vitro study

A growing awareness of dental aesthetics and patient demands for tooth coloured restorations have led to an increasing number of choices for resin based dental restoratives. The aim of this study was to investigate the cytotoxicity of seven different resin based restorative materials widely used in clinical dentistry. The materials tested included two glass ionomer cements (Ionofil U and Ketac Molar Easymix), one compomer (Dyract), three resin composites (Valux Plus, Alert and Filtek P-60) and one ormocer (Admira). Specimens were fabricated in sterile, cylindrical Teflon moulds (4·4 mm diameter ×2 mm height) under aseptic conditions. For each material, 21 discs were fabricated and randomly divided into three groups. Samples were immersed in Dulbecco's modified Eagle's medium and incubated for 24 h, 48 h or 10 days at 37°C with 5%CO2 and 95% air. Fresh Dulbecco's modified Eagle's medium was used as a control. Cytotoxicity was measured using the 3-(4·5-dimethylthiazol-2-yl)-2·5-diphenyltetrazolium bromide assay. At the end of 24 h, all materials except for Alert and Filtek exhibited significant cytotoxic effects on mouse fibroblast cells. At 48 h, only the glass ionomer cements (Ionofil and Ketac Molar) showed significantly higher cytotoxicity than the control group. At the end of 10 days, none of the materials tested showed any significant difference in cytotoxicity from the control group. In conclusion, this study found five of seven resin based restorative materials tested to have significant cytotoxic effects at 24 h and two glass ionomer cements to have significant cytotoxic effects at 48 h.