Color stability of nonpigmented and pigmented maxillofacial silicone elastomer exposed to 3 different environments.

STATEMENT OF PROBLEM: The color degradation of maxillofacial prostheses in clinical service requires their frequent renewal. How different materials compare is unclear. PURPOSE: The purpose of this in vitro study was to investigate the color stability of a nonpigmented and pigmented maxillofacial silicone when stored in darkness and exposed to accelerated aging in a weathering chamber and natural outdoor weathering. MATERIAL AND METHODS: M511 elastomer was colored with Spectromatch Pro colorants, stored in darkness, and exposed to accelerated aging and natural outdoor weathering for 1500 hours. Test groups included nonpigmented specimens (n=18), individually pigmented specimens (n=90), and Caucasian skin tone-colored specimens (n=18). The CIELab values of the test specimens were measured using the CM-2600d spectrophotometer (Konica Minolta Sensing) at base line (0 hours) and then every 100 hours up to 1500 hours of aging. Color changes (ΔE) were calculated based on the recorded CIELab values. All data were analyzed by using linear mixed models and the Sídák multiple comparison of means test (α=.05). RESULTS: A significant effect of time was found on the ΔE of all test specimens in all environments (P=.001). All pigmented M511 specimens demonstrated good color stability with maximum ΔE below the acceptability threshold of 2 ΔE when stored in darkness and exposed to outdoor weathering. However, nonpigmented specimens crossed this acceptability threshold when exposed to outdoor weathering with maximum ΔE values of 3.65. The greatest color changes were observed for all specimens when exposed to accelerated aging and most exceeded the acceptability threshold. Nonpigmented (ΔE, 4.86) and Indian yellow (ΔE, 5.20) demonstrated the highest color changes after 1500 hours. CONCLUSIONS: All environments resulted in visible color changes of nonpigmented and pigmented M511 elastomer. The lowest ΔE values were observed for specimens stored in darkness and the greatest for specimens exposed to accelerated aging. The organic pigment Logwood maroon demonstrated the best color stability with maximum ΔE values below the perceptibility threshold (PT) of 1 ΔE.

Surgical spacer placement prior carbon ion radiotherapy (CIRT): an effective feasible strategy to improve the treatment for sacral chordoma.

BACKGROUND: Sacral chordoma (SC) is a neoplasm arising from residual notochordal cells degeneration. SC is difficult to manage mainly because of anatomic location and tendency to extensive spread. Carbon ion radiotherapy (CIRT) is highly precise to selectively deliver high biological effective dose to the tumor target sparing the anatomical structure on its path even if when SC is contiguous to the intestine, and a surgical spacer might be an advantageous tool to create a distance around the target volume allowing radical curative dose delivery with a safe dose gradient to the surrounding organs. This paper describes a double approach-open and hand-assisted laparoscopic-for a silicon spacer placement in patients affected by sacral chordoma undergoing carbon ion radiotherapy. METHODS: Six consecutive patients have been enrolled for surgical spacer placement-open (three) or hand-assisted (three)-prior carbon ion radiotherapy treatment in order to increase efficacy of carbon ion radiotherapy minimizing its side effects. RESULTS: Results showed that silicon spacer placement for SC treatment is feasible both via laparoscopic and laparotomic approach. CONCLUSIONS: Its use might improve CIRT safety and thus efficacy for SC treatment.

Effect of light aging on silicone-resin bond strength in maxillofacial prostheses.

PURPOSE: The aim of this study was to investigate the effect of accelerated light aging on bond strength of a silicone elastomer to three types of denture resin. MATERIALS AND METHODS: A total of 60 single lap joint specimens were fabricated with auto-, heat-, and photopolymerized (n = 20) resins. An addition-type silicone elastomer (Episil-E) was bonded to resins treated with the same primer (A330-G). Thirty specimens served as controls and were tested after 24 hours, and the remaining were aged under accelerated exposure to daylight for 546 hours (irradiance 765 W/m(2) ). Lap shear joint tests were performed to evaluate bond strength at 50 mm/min crosshead speed. Two-way ANOVA and Tukey's test were carried out to detect statistical significance (p < 0.05). RESULTS: ANOVA showed that the main effect of light aging was the most important factor determining the shear bond strength. The mean bond strength values ranged from 0.096 to 0.136 MPa. The highest values were recorded for auto- (0.131 MPa) and photopolymerized (0.136 MPa) resins after aging. CONCLUSIONS: Accelerated light aging for 546 hours affects the bond strength of an addition-type silicone elastomer to three different denture resins. The bond strength significantly increased after aging for photo- and autopolymerized resins. All the bonds failed adhesively.

The effect of accelerated ageing on colour stability of visible light-cured (VLC) chairside denture liners.

OBJECTIVE: The purpose of this study was to assess the colour stability of seven visible light-cured (VLC) hard and soft denture liners by an in vitro accelerated ageing test and compare them with two autopolymerised hard and soft liners. MATERIALS AND METHODS: Ten specimens of each material were fabricated. The initial colour was measured with a tri-stimulus colorimeter. One set of five specimens was placed in distilled water at 37°C in the dark for 15 days, while the remaining were subjected to UV/visible light-accelerated ageing initially for 24 h and then for 144 h. Colour change (ΔΕ) was calculated. Data were statistically analysed by anova, Tukey and t-tests at α = 0.05. RESULTS: All the liners showed clinically acceptable colour change (ΔΕ ≤ 6.8) in distilled water. The colour changes after ageing for Triad DuaLine, Lightdon U, Ufi Gel H and Light Liner Hard were clinically unacceptable (ΔΕ ≥ 6.8), whereas LightLiner Soft, Astron LC Soft, Triad Resiline and Flexacryl Soft presented slighter and clinically acceptable colour change (ΔΕ ≤ 6.8). CONCLUSION: Accelerated ageing affected significantly the colour stability of all denture liners tested except Astron LC Soft. Soft VLC denture liners were more colour-stable than hard VLC liners.

Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation.

BACKGROUND: This study evaluated the effect of disinfection by immersion and microwave irradiation on the roughness of one denture base resin (Lucitone-L) and five relining materials, three hard (Tokuyama Rebase II-TR, New Truliner-NT, Ufigel Hard-UH) and two resilient (Trusoft-T, Sofreliner-S). METHODS: Fifty specimens were made and divided into groups: CL2 specimens were brushed with 4% chlorhexidine (1 min), immersed in the same solution (10 min) and immersed in water (3 min); MW2 specimens were immersed in water and microwave irradiated (650W; 6 min); CL2 and MW2 specimens were disinfected twice; CL7 and MW7 specimens were submitted to seven cycles using chlorhexidine or microwave irradiation, respectively; W specimens were not disinfected and remained in water (37°C; 7 days). RESULTS: Results were statistically analysed (p = 0.05) and revealed that, at baseline, the highest mean value was observed for T (p < 0.001). Material NT showed increase in roughness after the first (p = 0.003), second (p = 0.001), seventh (p = 0.000) cycles of microwave disinfection and after 7 days of immersion in water (p = 0.033). CONCLUSIONS: Resilient liner S presented significant increase in roughness after the second cycle of disinfection with chlorhexidine (p = 0.003). Material T exhibited significantly decreased roughness in group W (p = 0.010), while microwaving produced severe alterations on its surface.

Effect of different surface treatments on tensile bond strength of silicone-based soft denture liner.

Failure of the bond between the acrylic resin and resilient liner material is commonly encountered in clinical practice. The purpose of this study was to investigate the effect of different surface treatments (sandblasting, Er:YAG, Nd:YAG, and KTP lasers) on tensile bond strength of silicone-based soft denture liner. Polymethyl methacrylate test specimens were fabricated and each received one of eight surface treatments: untreated (control), sandblasted, Er:YAG laser irradiated, sandblasted + Er:YAG laser irradiated, Nd:YAG laser irradiated, sandblasted + Nd:YAG laser irradiated, KTP laser irradiated, and sandblasted + KTP laser irradiated. The resilient liner specimens (n = 15) were processed between two polymethyl methacrylate (PMMA) blocks. Bonding strength of the liners to PMMA were compared by tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. Kruskal-Wallis and Wilcoxon tests were used to analyze the data (α = 0.05). Altering the polymethyl methacrylate surface by Er:YAG laser significantly increased the bond strengths in polymethyl methacrylate/silicone specimens, however, sandblasting before applying a lining material had a weakening effect on the bond. In addition, Nd:YAG and KTP lasers were found to be ineffective for increasing the strength of the bond.

Influence of pigments and opacifiers on color stability of an artificially aged facial silicone.

PURPOSE: The aim of this study was to evaluate the influence of two pigments (ceramic powder and oil paint) and one opacifier (barium sulfate) on the color stability of MDX4-4210 facial silicone submitted to accelerated aging. MATERIALS AND METHODS: Sixty specimens of silicone were fabricated and divided into six groups--colorless (G1), colorless with opacifier (G2), ceramic (G3), ceramic with opacifier (G4), oil (G5), oil with opacifier (G6). All replicas were submitted to accelerated aging for 1008 hours. The evaluations of chromatic alteration through visual analysis and reflection spectrophotometry were carried out initially and after 252, 504, and 1008 hours of aging. The results were submitted to ANOVA and Tukey's test at 5% level of significance. RESULTS: All groups exhibited chromatic alteration (ΔE > 0); however, this color alteration was not perceptible through visual analysis of the color. The pigmented groups with opacifier presented the lowest ΔE values, with a statistical difference from the other groups. For the groups without opacifier, the group pigmented with oil paint exhibited the lowest ΔE values in the different aging periods, with a statistical difference. Accelerated aging generated significant chromatic alterations in all groups after 252 hours, except for the colorless and oil groups, both with opacifier (G2 and G6). CONCLUSIONS: The opacifier protects facial silicones against color degradation, and oil paint is a stable pigment even without addition of opacifier.

Dynamic mechanical properties of a maxillofacial silicone elastomer incorporating a ZnO additive: the effect of artificial aging.

The main objective of the current study was to investigate the dynamic mechanical properties of a room-temperature vulcanizing silicone incorporating different fractions of zinc oxide (ZnO) after indoor and outdoor photoaging. Forty-eight samples were produced by adding different amounts of ZnO into a commercial maxillofacial silicone (EPISIL-E). The samples were divided into 4 groups containing 0.0, 0.2, 0.5, and 1 wt% ZnO additive, respectively. Samples were exposed to sunlight (subgroup 2), ultraviolet (subgroup 3), and fluorescence (subgroup 4) aging, whereas nonaged samples comprised the control subgroup (subgroup 1). Dynamic mechanical analysis was used to determine the storage modulus (E'), loss modulus (E″), and damping capacity (tanδ). General linear statistic model was conducted to evaluate the effects of aging, testing frequency, and composition on the dynamic mechanical properties of the silicone with the ZnO additive. Post hoc analysis was performed using Tukey test. Statistical analysis revealed a significant impact of composition on tanδ (P < 0.05). Aging influenced E' and E″ (P < 0.01). The combination of aging and composition had a significant effect on all dynamic properties (P < 0.01).

Glass transition temperature of hard chairside reline materials after post-polymerisation treatments.

OBJECTIVE: This study evaluated the effect of post-polymerisation treatments on the glass transition temperature (T(g)) of five hard chairside reline materials (Duraliner II-D, Kooliner-K, New Truliner-N, Ufi Gel hard-U and Tokuso Rebase Fast-T). MATERIALS AND METHODS: Specimens (10 x 10 x 1 mm) were made following the manufacturers' instructions and divided into three groups (n = 5). Control group specimens were left untreated. Specimens from the microwave group were irradiated with pre-determined power/time combinations, and specimens from the water-bath group were immersed in hot water at 55 degrees C for 10 min. Glass transition ( degrees C) was performed by differential scanning calorimetry. Data were analysed using anova, followed by post hoc Tukey's test (alpha = 0.05). RESULTS: Both post-polymerisation treatments promoted a significant (p < 0.05) increase in the T(g) of reline material K. Materials K, D and N showed the lowest T(g) (p < 0.05). No significant difference between T and U specimens was observed. CONCLUSION: Post-polymerisation treatments improved the glass transition of material Kooliner, with the effect being more pronounced for microwave irradiation.

Effects of accelerated artificial daylight aging on bending strength and bonding of glass fibers in fiber-embedded maxillofacial silicone prostheses.

PURPOSE: The purpose of this study was to test the effect of different periods of accelerated artificial daylight aging on bond strength of glass fiber bundles embedded into maxillofacial silicone elastomer and on bending strength of the glass fiber bundles. METHODS AND MATERIALS: Forty specimens were fabricated by embedding resin-impregnated fiber bundles (1.5-mm diameter, 20-mm long) into maxillofacial silicone elastomer. Specimens were randomly allocated into four groups, and each group was subjected to different periods of accelerated daylight aging as follows (in hours); 0, 200, 400, and 600. The aging cycle included continuous exposure to quartz-filtered visible daylight (irradiance 760 W/m(2)) under an alternating weathering cycle (wet for 18 minutes, dry for 102 minutes). Pull-out tests were performed to evaluate bond strength between fiber bundles and silicone using a universal testing machine at 1 mm/min crosshead speed. Also a three-point bending test was performed to evaluate bending strength of the fiber bundles. One-way ANOVA and Bonferroni post hoc tests were carried out to detect statistical significance (p < 0.05). RESULTS: Mean (SD) values of maximum pull-out forces (in N) for groups 1 to 4 were: 13.63 (7.45), 19.67 (1.37), 13.58 (2.61), and 10.37 (2.52). Group 2 exhibited the highest pull-out force that was statistically significant when compared to the other groups. Maximum bending strengths of fiber bundles were in the range of 917.72 MPa to 1124.06 MPa. Bending strength significantly increased after 200 and 400 hours of aging only. CONCLUSIONS: After 200 hours of exposure to artificial daylight and moisture conditions, bond strength between glass fibers and heat-cured silicones is optimal, and the bending strength of the glass fiber bundles is enhanced.

Influence of microwave disinfection on the dimensional stability of denture reline polymers.

PURPOSE: The purpose of this study was to evaluate the effect of microwave disinfection (3 minutes at 650 W) on the dimensional stability of hard chairside reline resins (Kooliner, Tokuyama Rebase II, Ufi Gel hard, New Truliner) and one heat-polymerizing denture base resin (Lucitone 550). MATERIALS AND METHODS: A split mold with reference points was used to make specimens (50.0-mm diameter, 0.5-mm thick) from each material, divided into five test groups (n = 8). The distances between the points on the mold were measured (gold standard), and compared with those obtained from the specimens after polymerization (baseline readings) after one, two, three, and four cycles of disinfection by microwave irradiation. RESULTS: ANOVA and Tukey tests (alpha= 0.05) showed that Kooliner was significantly affected by all disinfection cycles (p < 0.05) when compared with baseline measurements. New Truliner resin was significantly affected by three and four cycles of microwave disinfection when compared with baseline measurements (p < 0.05). For Tokuyama Rebase II, Ufi Gel hard, and Lucitone 550, no significant dimensional changes were found. CONCLUSIONS: Microwave disinfection promoted shrinkage of Kooliner and New Truliner. The dimensional stability of Tokuyama Rebase II, Ufi Gel Hard, and Lucitone 550 was not affected by microwave disinfection.

The occurrence of porosity in reline acrylic resins. Effect of microwave disinfection.

BACKGROUND: Microwave energy has proved to be an effective method for disinfecting acrylic dentures. However, the effect of microwave heating on the porosity of autopolymerising denture reline resins has not been investigated. OBJECTIVE: The purpose of the study was to determine the effect of microwave disinfection on the porosity of autopolymerised denture reline materials (Kooliner-K, New Truliner-NT, Tokuso Rebase Fast-TR and Ufi Gel Hard-UGH) and a conventional heat-polymerised denture base resin (Lucitone 550-L). MATERIAL AND METHODS: Specimens (10 mm x 20 mm x 1 mm) were obtained from the impression surface of the palatal mucosa in a single person and divided into four groups (n = 5). The porosity was evaluated after polymerisation (C1), after two cycles of microwave disinfection (MW2), after seven cycles of microwave disinfection (MW7) and after 7 days storage in water at 37 degrees C (C2). Specimens from group MW7 were exposed to microwave disinfection daily being stored in water at 37 degrees C between exposures. All the replicas were sputter coated with gold and micrographs/digital images were taken of each replica using scanning electron microscopy at magnification x 100. The SEM micrographs were then examined using an image analyser to determine the number of pores. Comparison between materials and groups were made using Kruskal-Wallis tests. RESULTS: MW7 resulted in a significant increase in the number from the pores of material K, but decreased in number in reline material TR and UGH reline resin. The number of pores in materials NT and L remained unaffected following microwave disinfection. CONCLUSION: Differences in the porosity amongst the materials and for different experimental conditions were observed following microwave disinfection.

[Study of risk factors of laser irradiation-induced intraocular lens damage].

The rate of distant damages to intraocular lens (IOL) was studied in relation to its material and manufacture procedure (punching or turning), and its posterior lens capsular position in 120 patients (125 eyes) who had undergone laser secondary cataract discussion. The resistance of lenses made from silicone, polymethylmethacrylate (PMMA), and acryl to YAG laser irradiation (1.076 microm) was studied in an experiment. The findings suggest that the risk for distant IOL damaged in YAG-capsulotomy is higher in PMMA lenses made by punching and silicone IOL. Artificial acryl lenses show a high resistance to YAG laser irradiation. The nature and depth of IOL damages are not entirely determined by the physical properties of a lens material and they are also associated with the distance of a lens and an irradiated structure. If there are specific posterior capsular changes as jelly-like thickening and if convex-designed lenses are implanted, then there is no safe distance between the capsule and IOL, which permanently leads to its damage by YAG-laser irradiation.

The effect of post-mastectomy radiation therapy on breast implants: Unveiling biomaterial alterations with potential implications on capsular contracture.

Post-mastectomy breast reconstruction with expanders and implants is recognized as an integral part of breast cancer treatment. Its main complication is represented by capsular contracture, which leads to poor expansion, breast deformation, and pain, often requiring additional surgery. In such a scenario, the debate continues as to whether the second stage of breast reconstruction should be performed before or after post-mastectomy radiation therapy, in light of potential alterations induced by irradiation to silicone biomaterial. This work provides a novel, multi-technique approach to unveil the role of radiotherapy in biomaterial alterations, with potential involvement in capsular contracture. Following irradiation, implant shells underwent mechanical, chemical, and microstructural evaluation by means of tensile testing, Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy (ATR/FTIR), Scanning Electron Microscopy (SEM), high resolution stylus profilometry, and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Our findings are consistent with radiation-induced modifications of silicone that, although not detectable at the microscale, can be evidenced by more sophisticated nanoscale surface analyses. In light of these results, biomaterial irradiation cannot be ruled out as one of the possible co-factors underlying capsular contracture.

Accelerated hydrolytic and ultraviolet aging studies on SI-18NB and SI-20NB silicone lenses.

This report describes the results of in vitro accelerated hydrolytic and ultraviolet aging studies performed on SI-18NB and SI-20NB silicone intraocular lenses. The hydrolytic aging study simulated the effects of 20 years in vivo. The ultraviolet aging study simulated the effects of 17 years in vivo. No significant changes in the focal length and resolution of the lenses were observed. Examination of the lens surfaces using scanning electron microscopy revealed no changes in surface morphology.

Effect of neodymium:YAG laser photodisruption on intraocular lenses in vitro.

Poly(methyl methacrylate) (PMMA) based intraocular lenses (IOLs) such as injection-molded PMMA and lathe-cut PMMA IOLs and soft IOLs such as silicone and poly(hydroxyethyl methacrylate)(polyHEMA) IOLs were tested for vulnerability to Nd:YAG laser photodisruption. The laser beam was focused on the posterior surface and inside of the IOLs in balanced salt solution. Cracks and central defects with radiating fractures were observed in PMMA IOLs; blistered lesions and localized pits were observed in silicone and polyHEMA IOLs, respectively. A molten edge surrounding the large hole, which was an indication of the thermal effect of the laser, was observed in the injection-molded PMMA while only a minute lesion was found in the polyHEMA IOL which contained 38% water. The size of the superficial damage of the IOL increased as the power of laser irradiation increased and PMMA IOLs showed greater damage than soft IOLs (P < .05).

Accelerated ultraviolet aging of intraocular lens optic materials: a 50 year simulation.

PURPOSE: To introduce an updated accelerated photoaging model for application to intraocular lens (IOL) materials and to apply this model to determine the photostability of AMO PhacoFlex model SI-18NGB and PhacoFlex II model SI-20NGB silicone IOL materials over a simulated 50 years of exposure. SETTING: Research laboratory, AMO Surgical Products, Irvine, California, USA. METHODS: Previous photoaging models and aging parameters, including intraocular exposure intensity, daily exposure duration, and acceleration exponent were critically reviewed and analyzed, and an updated model was introduced. The test specimens were continuously irradiated with ultraviolet (UV) light in a Suntest UV chamber at an intensity of 8 mw/cm2 for 86 days to simulate 50 years of in vivo exposure. The silicone lenses were evaluated for focal length, resolution, and surface integrity, while regular slabs were tested for tensile strength, elongation, hardness, contact angle, and percentage light transmission. The UV-absorption capacity was monitored using ultrathin slabs (0.127 mm). Six replicate samples were used for each determination, and a two-sided t-test with significance set at P < .05 was used to evaluate the difference before and after aging. RESULTS: No significant difference in optical, physical, and surface properties of the lenses and lens materials was found. No change in UV-absorption capacity was observed after a simulated 50 years of accelerated photoaging. CONCLUSION: The AMO PhacoFlex SI-18NGB and PhacoFlex II SI-30NGB silicone lens materials resisted UV light degradation over 50 years of simulated exposure.

Blood compatibility of tubular polymeric materials studied by biological surface interactions.

Tubular polymeric materials modified by radiation techniques can be used as vascular prosthesis and components of prosthetic devices. The biological interaction between these materials and blood was studied by in vitro and ex vivo methods. Silicone rubber tubes were copolymerized with acrylamide and N-vinylpyrrolidone by radiation-grafting techniques. The irradiation was performed with gamma-rays from a 60Co source at a constant dose rate (0.2 kGy/h) for various time intervals (4-15 h). To evaluate the antithrombogenicity of the grafted tubes, the surface adsorption of 125I-albumin and 125I-fibrinogen was studied. All graft copolymers show a preference for albumin, and the degree of preference appears to correlate with antithrombogenic tendency. In the ex vivo experiment with animals, tubes were implanted in the carotid artery of dogs and the blood flow in the graft copolymers was detected with an ultrasonic flow meter. The blood flow rate in the ungrafted implants decreased more rapidly (stopped completely after 15 to 210 min) compared to the flow rate in the grafted ones (decreased slowly from 38 to 35 ml/min and 70 to 60 ml/min). There was a direct relationship between both methods in the study of blood compatibility of the materials. The results suggest that the graft copolymers can be used as biomaterials for long-term use in cardiovascular systems.

The effects of radiation therapy on the tissue capsule of soft tissue implants.

A prosthesis has been developed for cosmesis after lumpectomy surgery for breast carcinoma. The device is saline filled and percutaneously adjustable in volume to permit an optimal cosmetic result after surgical wound healing. A series of 24 studies of 18 weeks' duration using the adult rabbit animal model were first used to study tissue capsule formation around textured versus smooth surface control implants and to evaluate the effects of volume adjustments on the tissue capsule. Single or multiple adjustments of implant volume had no effect on tissue capsule thickness or morphology. Because lumpectomy surgery is invariably followed by radiation therapy, a series of six studies was then conducted to determine the effects of a typical course of radiation therapy on tissue capsule formation. One week after device implantation, a 4 x 4 cm field including the implant was irradiated with 5,000 rad (200 rad/day x 5 days/week x 5 weeks). The animals were maintained for a 6 week period after radiation treatment. After sacrifice, the implants were removed, and the tissue capsules studied using conventional histologic techniques, including scanning and transmission electron microscopy. There was no statistically significant difference in tissue capsule thickness compared to nonirradiated controls. Tissue capsule morphology, however, differed markedly. Radiation therapy decreased angiogenesis, cellularity, and the inflammatory cell response to the implants. Qualitatively, radiation treatment seemingly improved rather than compromised the connective tissue response to the implants.

Biomechanical properties of nano-TiO(2) addition to a medical silicone elastomer: the effect of artificial ageing.

OBJECTIVES: The aim of this study was to evaluate the effect of TiO2 nanoparticles on the mechanical and anti-ageing properties of a medical silicone elastomer and to assess the biocompatibility of this novel combination. METHODS: TiO2 (P25, Degussa, Germany) nanoparticles were mixed with the silicone elastomer (MDX4-4210, Dow Corning, USA) at 2%, 4%, and 6% (w/w) using silicone fluid as diluent (Q7-9180, Dow Corning, USA). Blank silicone elastomer served as the control material. The physical properties and biocompatibility of the composites were examined. The tensile strength was tested for 0% and 6% (w/w) before and after artificial ageing. SEM analysis was performed. RESULTS: TiO2 nanoparticles improved the tensile strength and Shore A hardness of the silicone elastomer (P<0.05). However, a decrease in the elongation at break and tear strength was found for the 6% (w/w) composite (P<0.05). All the ageing methods had no effect on the tensile strength of the 6% (w/w) composite (P>0.05), but thermal ageing significantly decreased the tensile strength of the control group (P<0.05). Cellular viability assays indicated that the composite exhibited biocompatibility. CONCLUSIONS: We obtained a promising restorative material which yields favourable physical and anti-ageing properties and is biocompatible in our in vitro cellular studies.