Effect of ethylene oxide unit number in bis-EMA on the physical properties of additive-manufactured occlusal splint material.

PURPOSE: To investigate the effects of the number of ethylene oxide units in bis-EMA on the physical properties of additively manufactured occlusal splints. METHODS: Seven experimental materials containing bis-EMAs with three and 10 ethylene oxide units (BE3 and BE10, respectively) were prepared at different BE10 content rates (BE10-0%, -20%, -30%, -40%, -50%, -60%, and -80%). Half the specimens of each material were aged in boiling water. Flexural strength (FS), flexural modulus (FM), fracture toughness (FT), microwear depth (MD), degree of conversion (DC), water sorption (WSP), water solubility (WSL), color difference between non-aged and aged series (ΔE), and translucency (TP) were evaluated. All the evaluated properties other than FS and MD were analyzed by 1-way ANOVA and Tukey's post hoc analysis, while FS and MD were analyzed by Kruskal-Wallis's test and Bonferroni correction (α=0.05). RESULTS: BE10-80% revealed the lowest FS (P < 0.01 for BE10-0%, -20%, and -30%) and FM (P < 0.01, for all), while revealing the highest DC, WSP, WSL (P < 0.01 for all) and TP (P < 0.01 for all other than BE10-60%). BE10-50% showed the highest FT (P < 0.01 for all). BE10-50%, -60%, and -80% revealed significantly lower ΔE than others (P < 0.01) and lower MD than BE10-0% (P < 0.05). Regardless of the BE10 content, FS, FM, and FT decreased with aging. CONCLUSIONS: The number of ethylene oxide units affects the physical properties of additively manufactured occlusal splints. The higher number of ethylene oxide units in bis-EMA enhanced the microwear resistance, DC, WSP, WSL, color stability, and translucency, whereas it deteriorated the FS and FM.

Effect of Surface Polishing on Physical Properties of an Occlusal Splint Material for Additive Manufacturing under Protection Gas Post-Curing Condition.

The aim of this study was to evaluate the effect of surface polishing as well as the post-curing atmospheres (air and nitrogen gas) on the physical properties of an occlusal splint material for additive manufacturing. Flexural strength, flexural modulus, Vickers hardness number (VHN), degree of carbon double bond conversion (DC), water sorption (WSP), and water solubility (WSL) were evaluated. Surface polishing significantly affected the evaluated properties. Regardless of the post-curing atmosphere, flexural strength, flexural modulus, VHN, and DC showed significantly higher values for the polished specimens when compared with the unpolished ones, while WSP and WSL were significantly lower for the polished specimens. Unpolished specimens post-cured at nitrogen gas showed significantly higher VHN and DC values. However, the effect of the post-curing at a nitrogen gas atmosphere was non-significant in polished specimens. The current results suggested that surface polishing plays a role in the physical properties of the evaluated occlusal splint material and can enhance all the evaluated properties regardless of the post-curing atmosphere. Meanwhile, the post-curing at a nitrogen gas atmosphere can enhance the VHN and DC but its effect is confined only to the surface layers, which can be removed during surface polishing.

Effect of 3D Printer Type and Use of Protection Gas during Post-Curing on Some Physical Properties of Soft Occlusal Splint Material.

Despite the fact that three-dimensional (3D) printing is frequently used in the manufacturing of occlusal splints, the effects of the 3D printer type and post-curing methods are still unclear. The aim of this study was to investigate the effect of the printer type (digital light processing: DLP; and liquid crystal display: LCD) as well as the post-curing method with two different atmospheric conditions (air and nitrogen gas (N2)) on the mechanical and surface properties of 3D-printed soft-type occlusal splint material. The evaluated properties were flexural strength, flexural modulus, Vickers hardness (VHN), fracture toughness, degree of double bond conversion (DC%), water sorption, water solubility, and 3D microlayer structure. The printer type significantly affected all the evaluated properties. Flexural strength, flexural modulus, and fracture toughness were significantly higher when specimens were printed by a DLP printer, while VHN and DC% were significantly higher, and a smoother surface was noticeably obtained when printed by an LCD printer. The post-curing at an N2 atmosphere significantly enhanced all of the evaluated properties except water sorption, 3D microlayer structure, and fracture toughness. The current results suggested that the printer type and the post-curing methods would have an impact on the mechanical and surface properties of the evaluated material.

Effect of Nitrogen Gas Post-Curing and Printer Type on the Mechanical Properties of 3D-Printed Hard Occlusal Splint Material.

Although three-dimensional (3D) printing is clinically convenient to fabricate occlusal splints, it is still unclear how the post-curing method and the printer type can affect 3D-printed splints. This study aimed to evaluate the effect of stroboscopic post-curing at a nitrogen gas (N2) atmosphere versus post-curing in an air atmosphere, as well as the printer type (liquid crystal display (LCD) and digital light processing (DLP)) on the mechanical properties of a 3D-printed hard-type occlusal splint material. Flexural strength, flexural modulus, Vickers hardness number (VHN), fracture toughness, degree of double bond conversion (DC), 3D microlayer structure, water sorption, and water solubility were evaluated. The post-curing method significantly affected all evaluated properties except fracture toughness and 3D microlayer structure, while the printer type significantly affected all evaluated properties except flexural strength and flexural modulus. VHN and DC were significantly higher, and the smoother surface was noticeably obtained when printed by LCD printer and post-cured at an N2 atmosphere. The current results suggested that the post-curing method and the printer type would play a role in the mechanical properties of the evaluated material and that the combination of post-curing at an N2 atmosphere and LCD printer could enhance its mechanical properties and surface smoothness.

Quasi-static loading of glass fiber-reinforced composite cervical fusion cage.

OBJECTIVES: Anterior decompression and fusion in cervical spine has become one of the most common procedures in neurosurgery. In the surgery, cervical cage implants made of different biomaterials are used. Our purpose was to create a cervical cage made of glass fiber-reinforced composite (FRC) filled with bioactive glass particles and to characterize its behavior in quasi-static compression/shear stress loading conditions. MATERIALS AND METHODS: FRC cages (n = 6) were manufactured with 2, 4, 6, 8 and 10 layers of glass fiber laminates and thermoset dimethacrylate resin matrix resulting in wall thickness from 0.70 to 2.1 mm. Control cage was a commercial PEEK cage (CeSpaceXP) implant with asymmetrical wall thickness of up 4.0 mm. Interior of the cage was filled with glass particles of the size 500-1250 µm simulating the bioactive glass which are used in FRC cranial implants. The FRC cages were quasi-statically loaded (compressive/shear stress) at a constant speed of 1 mm/min in the air. RESULTS: The average yield strength force (YF) of the control PEEK cage was 3483.6 N (±134.3 N). The average YFs for tested FRC cage with 2, 4, 6, 8 and 10 layers of FRC fabric varied from 1336.5 N (±403.8 N) to 7675.0 N (±670.0 N), respectively. The average ultimate forces (UF) for tested FRC cages varied from 1535.8 N (±406.2 N) to 9975.0 N (±1492.4 N). With six layers of FRC fabric, YF of the FRC cage was comparable to the PEEK implants. CONCLUSIONS: In this study, it was demonstrated that it is possible to manufacture a cervical interbody fusion device made of FRC and filled with bioactive glass with proper load bearing capacities. Because of physical properties of FRC-bioactive glass, the FRC cage might have some advances compared to the state-of-the-art cages, like faster bony union and smaller rate of subsidence, which will be studied in the future.

Structural and elemental characterization of glass and ceramic particles for bone surgery.

OBJECTIVE: Clinically used bioceramics have been characterized previously with different kinds of methods and comparison of results have proven to be difficult due to varieties of the material properties of interest. Therefore, in this study we compared clinically commonly used bioceramics of hydroxyapatite and carbonate apatite, two bioactive glasses 45S5 and S53P4, and alumina with respect of properties which according to the present knowledge are significant for bone biology. METHODS: Physicochemical properties of the materials were characterized by various methods. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) was used to analyze the material vibrational features. X-ray Power Diffraction (XRD) was used to characterize the material crystal structure and scanning electron microscopy-energy-dispersive x-ray analysis (SEM-EDXA) was used to evaluate the morphology and size of the materials and to calculate their oxide content. The dissolution behavior of the materials, ion release and pH changes in Tris buffer in a continuous flow-through reaction for 24-hours were determined. The change of the surface of the bioactive glasses by interfacial reaction during the Tris immersion was examined and the thickness of the surface reaction layer of the materials was studied. RESULTS: SEM examination showed that the particle morphology of BG 45S5, BG S53P4 and alumina particle's surface was smooth. The surface of HAP was porous, but also CAP showed some surface porosity. An increase in the pH of the immersion solution was observed especially for BG 45S5 and BG S53P4. HAP, CAP and alumina caused only a minor increase in pH. BGs 45S5 and S53P4 showed a rapid initial release of sodium and calcium ions, followed by the release of silicon species. Minor release of sodium ions was registered for HAP, CAP and alumina. Calcium ion release was low but constant over the experimental time while only a minor initial dissolution was measured for HAP. SIGNIFICANCE: The in vitro study showed differences in the materials' properties, which are considered to be important for biological suitability and in clinical applications, such as materials tomography, ion release and pH changes.

The Viability and Growth of HaCaT Cells After Exposure to Bioactive Glass S53P4-Containing Cell Culture Media.

HYPOTHESIS: Bioactive glass (BG) S53P4 reduces the viability of epidermal keratinocyte-derived immortalized cell line, HaCaT in sufficient concentrations in vitro. BACKGROUND: Although used in mastoid obliteration surgery, there is no data available on whether BG S53P4 granules have an inhibitory or excitatory effect on keratinocytes, found in normal skin and ear cholesteatoma in vivo. METHODS: HaCaT cell cultures were incubated with a direct BG S53P4 granule contact. Microscopic evaluation of the cultures was performed and interleukin-6 (IL-6) and -8 (IL-8) concentrations were measured from the medium samples. In addition, BG granules were incubated in two cell culture media for 6 days and the pure media were used in confluent HaCaT cultures preceding cell viability assay. Finally, a scratch assay test was performed to reveal the possible BG effect on HaCaT cultures. RESULTS: Eight to ten cell thick layers of dead HaCaT cells were noticed after a 2-day BG granule contact. With a BG concentration of 2.5%, IL-6 and IL-8 concentrations were smaller compared with the control group without BG after 2 days' incubation. Overall, HaCaT cell viability decreased when BG was incubated in keratinocyte growth medium, but did not change in Dulbecco's modified Eagle's medium. In a scratch assay test, cell regrowth in the scratch area was notable in cultures without BG. CONCLUSIONS: BG S53P4 seems to have an inhibitory effect on HaCaT cell growth. Although further studies are needed, this observation seems advantageous for cholesteatoma treatment.

Physicochemical properties of dimethacrylate resin composites with comonomer of Hexa/Tri-ethylene glycol bis(carbamate-isoproply-α-methylstyrene).

New photocurable "Phene" like monomers Hexaethylene glycol bis(carbamate-isoproply-α-methylstyrene) (HE-Phene) and Triethylene glycol bis(carbamate-isoproply-α-methylstyrene) (TE-Phene) were synthesized and incorporated into Bis-GMA/TEGDMA with the aim of reducing polymerization shrinkage without detriment to the physical and handling properties of the resin composites. Phene like monomers (HE/TE-Phene) were synthesized through a one-step reaction route, and their structures were confirmed by FT-IR and 1H-NMR spectra. HE/TE-Phene were incorporated into Bis-GMA/TEGDMA (50/50,wt/wt) with a series of mass fraction (from 0 wt.% to 40 wt.%). Experimental resin composites were prepared by mixing 29 wt.% of resin matrix to 71 wt.% of particulate-fillers. Degree of conversion (DC) was determined by FT-IR analysis. The volumetric shrinkage (VS) was calculated as a buoyancy change in distilled water by means of the Archimedes principle. Polymerization shrinkage-stress (SS) was measured using the tensilometer technique. The flexural strength (FS), modulus (FM), and fracture toughness (FT) were measured using a three-point bending setup. Viscosity was analyzed with a rotating disk rheometer. Water sorption and solubility were also measured. ANOVA analysis showed that DC (after 40 s), VS, and SS were in a trend of decreasing with the increasing of HE/TE-Phene concentration. In general, the experimental resin composites had comparable FT, FS and FM (p > 0.05) when the mass fraction of HE/TE-Phene in resin matrix was not more than 30 wt.%. The overall tested properties prove that including HE/TE-Phene up to 30 wt.% into Bis-GMA/TEGDMA resin could be potentially useful in the formulation of low-shrinkage resin composites.

Scattering of therapeutic radiation in the presence of craniofacial bone reconstruction materials.

PURPOSE: Radiation scattering from bone reconstruction materials can cause problems from prolonged healing to osteoradionecrosis. Glass fiber reinforced composite (FRC) has been introduced for bone reconstruction in craniofacial surgery but the effects during radiotherapy have not been previously studied. The purpose of this study was to compare the attenuation and back scatter caused by different reconstruction materials during radiotherapy, especially FRC with bioactive glass (BG) and titanium. METHODS: The effect of five different bone reconstruction materials on the surrounding tissue during radiotherapy was measured. The materials tested were titanium, glass FRC with and without BG, polyether ether ketone (PEEK) and bone. The samples were irradiated with 6 MV and 10 MV photon beams. Measurements of backscattering and dose changes behind the sample were made with radiochromic film and diamond detector dosimetry. RESULTS: An 18% dose enhancement was measured with a radiochromic film on the entrance side of irradiation for titanium with 6 MV energy while PEEK and FRC caused an enhancement of 10% and 4%, respectively. FRC-BG did not cause any measurable enhancement. The change in dose immediately behind the sample was also greatest with titanium (15% reduction) compared with the other materials (0-1% enhancement). The trend is similar with diamond detector measurements, titanium caused a dose enhancement of up to 4% with a 1 mm sample and a reduction of 8.5% with 6 MV energy whereas FRC, FRC-BG, PEEK or bone only caused a maximum dose reduction of 2.2%. CONCLUSIONS: Glass fiber reinforced composite causes less interaction with radiation than titanium during radiotherapy and could provide a better healing environment after bone reconstruction.

Characterization of osteogenic cells grown over modified graphene-oxide-biostable polymers.

Graphene is an excellent filler for the development of reinforced composites. This study evaluated bone cement composites of graphene oxide (GO) and poly(methyl methacrylate) (PMMA) based on the proliferation of human bone marrow mesenchymal stem cells (hBMSCs), and the anabolic and catabolic effects of the incorporation of GO on osteoblast cells at a genetic level. Surface wettability and roughness were also evaluated at different GO concentrations (GO1: 0.024 wt% and GO2: 0.048 wt%) in the polymer matrix. Fabricated specimens were tested to (a) observe cell proliferation and (b) identify the effectiveness of GO on the expression of bone morphogenic proteins. Early osteogenesis was observed based on the activity of alkaline phosphatase and the genetic expression of the run-related transcription factor 2. Moreover, bone strengthening was determined by examining the collagen type 1 alpha-1 gene. The surface roughness of the substrate material increased following the addition of GO fillers to the resin matrix. It was found that over a period of ten days, the proliferation of hBMSCs on GO2 was significantly higher compared to the control and GO1. Additionally, quantitative colorimetric mineralization of the extracellular matrix revealed greater calcium phosphate deposition by osteoblasts in GO2. Furthermore, alizarin red staining analysis at day 14 identified the presence of mineralization in the form of dark pigmentation in the central region of GO2. The modified GO-PMMA composite seems to be promising as a bone cement type for the enhancement of the biological activity of bone tissue.

A Large Calvarial Bone Defect in a Child: Osseointegration of an Implant.

BACKGROUND: This original report describes the outcome of a cranioplasty at long-term follow-up. A large calvarial bone defect of a child was reconstructed with a bioactive and biostable nonmetallic implant. CASE DESCRIPTION: In a child with infantile fibrosarcoma of occipital bone, the malignancy was removed at 2.5 years of age, and the defect site was reconstructed with an onlay glass fiber-reinforced composite-bioactive glass implant. The follow-up examination at 5 years 7 months showed no signs of tumor recurrence. During the follow-up period, the contour of the reconstructed area followed skull anatomic development. Computed tomography demonstrated considerably large areas (approximately 70% of the total area) of bone ongrowth to the peridural surface of the implant. CONCLUSIONS: In the future, a synthetic cranioplasty material that is able to integrate with cranial bone may be considered superior to cryopreserved bone grafts in younger age groups.

Patient specific glass fiber reinforced composite versus titanium plate: A comparative biomechanical analysis under cyclic dynamic loading.

OBJECTIVES: Free flap fixation with patient specific titanium (TI) plates is commonly performed after oncologic mandible resection, but plate exposure, osseous nonunion and imaging artefacts are associated complications. The aim of this study was to analyze interfragmentary movements and fatigue behaviour of patient specific titanium plates in comparison to a novel glass fiber reinforced composite (GFRC) plate in vitro. METHODS: Two polyurethane fibula segments were fixed to a corresponding mandible (Synbone AG, Malans, CH) with a patient specific 2.0 mm titanium plate (DePuy Synthes, Umkirch, Germany and Materialise, Leuven, Belgium) or one of two patient specific GFRC plates with different glass fiber orientation. Plate fixation to the fibula segments was performed with monocortical non-locking screws in all groups. Plate fixation to the mandible was performed with bicortical locking screws in the titanium group and with bicortical non-locking screws in the GFRC groups. Mastication was simulated via cyclic dynamic loading on the left side at a rate of 1 Hz with increasing peak loading (+0.15 N/cycle, Bionix, MTS, Eden Prairie, USA). A three-dimensional optical measuring system (PONTOS 5 M, GOM, Braunschweig, Germany) was used to determine interfragmentary movements between mandible and fibula segments. RESULTS: Mean plate stiffness of GFRC plates was 431 ±â€¯64 N/mm and 453 ±â€¯70 N/mm versus 560 ±â€¯112 N/mm in the titanium group. No significant differences were found for the number of loading cycles until a vertical displacement of 1.0 mm (p = 0.637) and for vertical displacement over time (p = 0.490). Interosteotomy gap movement differed significantly between titanium and GFRC plates in the right distal (p = 0.001), intermediate (p = 0.006) and left distal gap (p = 0.025). CONCLUSIONS: CAD/CAM titanium plates with locking screws provide increased stiffness and reduced interosteotomy movements in comparison to CAD/CAM glass fiber reinforced composite plates with non-locking titanium screws. Future studies should evaluate the influence of mechanobiologically optimized fixation systems on bone healing in free flap surgery.

The effect of smear layer removal on E. faecalis leakage and bond strength of four resin-based root canal sealers.

BACKGROUND: The aim of the study was to assess bacterial sealability and bonding ability of methacrylate-based Resilon (RS, SybronEndo), Endo Rez (ER, Ultradent Products Inc), and epoxy-based AH Plus (AH, Dentsply/DeTrey), MTA Fill Apex (MTAF, Angelus Soluções Odontológicas) root canal sealers, and the effect of the smear layer removal on the sealability. METHODS: One hundred thirty root segments were instrumented up to apical size #60 and rinsed with 2.5% NaOCl. Half of the roots were rinsed with 5ml 17% EDTA to remove the smear layer. All the roots were filled with AH, ER, MTAF sealers and gutta-percha, or RS with Resilon cones. After storage at 37°C for 7 days the samples were mounted into bacterial leakage assay for 50 days. Another 100 roots were instrumented and rinsed as described above, split longitudinally, cut into the cervical, middle and apical parts. The sealers were injected through the plastic mould on the dentin surface. After 7 days of incubation at 37°C, bond strength was tested using a notched-edge test fixture (Crosshead, Ultradent Products Inc.) and a universal testing machine (Lloyd Instruments). RESULTS: AH revealed the longest mean time for bacterial resistance by 29.4 and 36.8 days (with and without smear layer, respectively) followed by RS (15.1 and 24.7 days, respectively). The difference between materials was significant (p<0.001). Bond strength values ranged from 0.2± 0.1 to 3.5± 0.7 MPa and increased from the apical to the cervical third. In the apical third, AH showed the highest mean (SD) bond values 1.4 (0.4) MPa and 1.7 (0.6) MPa (with and without smear, respectively, followed by RS, 0.5 (0.1) MPa and 0.8 (0.1) MPa, respectively. The difference between materials was significant (p=0.001). CONCLUSION: The effect of the smear layer removal on the sealability was material-dependent.

Flexural and torsional properties of a glass fiber-reinforced composite diaphyseal bone model with multidirectional fiber orientation.

Although widely used, metallic implants have certain drawbacks in reconstructive bone surgery. Their high stiffness in respect to cortical bone can lead to complications which include periprosthetic fractures and aseptic loosening. In contrast to metallic alloys, fiber-reinforced composites (FRC) composed of a thermoset polymer matrix reinforced with continuous E-glass fibers have elastic properties matching those of bone. We investigated the mechanical properties of straight FRC tubes and FRC bone models representing the diaphysis of rabbit femur prepared from glass fiber/bisphenol A glycidyl methacrylate (BisGMA) - triethylene glycol dimethacrylate (TEGDMA) composite in three-point bending and torsion. Three groups of straight FRC tubes with different fiber orientations were mechanically tested to determine the best design for the FRC bone model. Tube 1 consisted most axially oriented unidirectional fiber roving and fewest bidirectional fiber sleevings. Fiber composition of tube 3 was the opposite. Tube 2 had moderate composition of both fiber types. Tube 2 resisted highest stresses in the mechanical tests and its fiber composition was selected for the FRC bone model. FRC bone model specimens were then prepared and the mechanical properties were compared with those of cadaver rabbit femora. In three-point bending, FRC bone models resisted 39-54% higher maximum load than rabbit femora with similar flexural stiffness. In torsion, FRC bone models resisted 31% higher maximum torque (p < 0.001) and were 38% more rigid (p = 0.001) than rabbit femora. Glass fiber-reinforced composites have good biocompatibility and from a biomechanical perspective, they could be used even in reconstruction of segmental diaphyseal defects. Development of an implant applicable for clinical use requires further studies.

Predictors of primary autograft cranioplasty survival and resorption after craniectomy.

OBJECTIVECraniectomy is a common neurosurgical procedure that reduces intracranial pressure, but survival necessitates cranioplasty at a later stage, after recovery from the primary insult. Complications such as infection and resorption of the autologous bone flap are common. The risk factors for complications and subsequent bone flap removal are unclear. The aim of this multicenter, retrospective study was to evaluate the factors affecting the outcome of primary autologous cranioplasty, with special emphasis on bone flap resorption.METHODSThe authors identified all patients who underwent primary autologous cranioplasty at 3 tertiary-level university hospitals between 2002 and 2015. Patients underwent follow-up until bone flap removal, death, or December 31, 2015.RESULTSThe cohort comprised 207 patients with a mean follow-up period of 3.7 years (SD 2.7 years). The overall complication rate was 39.6% (82/207), the bone flap removal rate was 19.3% (40/207), and 11 patients (5.3%) died during the follow-up period. Smoking (OR 3.23, 95% CI 1.50-6.95; p = 0.003) and age younger than 45 years (OR 2.29, 95% CI 1.07-4.89; p = 0.032) were found to independently predict subsequent autograft removal, while age younger than 30 years was found to independently predict clinically relevant bone flap resorption (OR 4.59, 95% CI 1.15-18.34; p = 0.03). The interval between craniectomy and cranioplasty was not found to predict either bone flap removal or resorption.CONCLUSIONSIn this large, multicenter cohort of patients with autologous cranioplasty, smoking and younger age predicted complications leading to bone flap removal. Very young age predicted bone flap resorption. The authors recommend that physicians extensively inform their patients of the pronounced risks of smoking before cranioplasty.

An overview of development and status of fiber-reinforced composites as dental and medical biomaterials.

Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions.

Hydroxyapatite and bioactive glass surfaces for fiber reinforced composite implants via surface ablation by Excimer laser.

In skeletal reconstructions, composites, such as bisphenol-A-glycidyldimethacrylate resin reinforced with glass fibers, are potentially useful alternatives to metallic implants. Recently, we reported a novel method to prepare bioactive surfaces for these composites. Surface etching by Excimer laser was used to expose bioactive glass granules embedded in the resin. The purpose of this study was to analyze two types of bioactive surfaces created by this technique. The surfaces contained bioactive glass and hydroxyapatite granules. The selected processing parameters were adequate for the creation of the surfaces. However, the use of porous hydroxyapatite prevented the complete exposure the granules. In cell culture, for bioactive glass coatings, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V) while inferior cell proliferation was observed on the surfaces containing hydroxyapatite granules. Scanning electron microscopy revealed osteointegration of implants with both types of surfaces. The technique is suitable for the exposure of solid bioactive glass granules. However, the long-term performance of the surfaces needs further assessment.

Preparation and characterization of high radio-opaque E-glass fiber-reinforced composite with iodine containing methacrylate monomer.

OBJECTIVE: The purpose of this study was to prepare radio-opaque E-glass fiber-reinforced composite (EFRC) with synthesized iodine containing methacrylate monomer. METHODS: The synthesized iodine containing methacrylate monomer 2-hydroxy-3- methacryloyloxypropyl(2,3,5- triiodobenzoate) (HMTIB) was mixed with Bis-GMA and MMA in different mass ratio to prepare resin impregnating solution (RIS), and RIS without HMTIB was used as control. CQ and DMAEMA were added as photoinitiation system. E-glass fiber was thoroughly wetted by resin impregnating solution to prepare radio-opaque EFRC. Degree of double bond conversion (DC) was investigated by FT-IR analysis. Fiber volume fraction was analyzed by combustion and gravimetric analyzes. The Flexural strength (FS) and modulus (FM) of EFRC were measured using a three-point bending set up. Water sorption (WS) and solubility (SL) were measured until the mass variation of EFRC in distilled water kept stable. Radiographs were taken to determine the radiopacity of EFRC. RESULTS: The FT-IR and 1H NMR spectra of HMTIB revealed that it was the same as designed. ANOVA analysis revealed that increasing HMTIB concentration in RIS would decrease DC and increase fiber volume fraction. When compared with control EFRC, all of HMTIB containing EFRCs had higher or comparable FS and FM, no matter before or after water immersion. WS of EFRC decreased with increasing HMTIB concentration, while SL was nearly kept the same. Radiopacity of EFRC increased with increasing HMTIB concentration. SIGNIFICANCE: The synthesized monomer HMTIB could be used to prepare EFRC with high radiopacity. Moreover, HMTIB containing EFRC would also have high mechanical properties and low WS.

A glass fiber-reinforced composite - bioactive glass cranioplasty implant: A case study of an early development stage implant removed due to a late infection.

This case study describes the properties of an early development stage bioactive glass containing fiber-reinforced composite calvarial implant with histology that has been in function for two years and three months. The patient is a 33-year old woman with a history of substance abuse, who sustained a severe traumatic brain injury later unsuccessfully treated with an autologous bone flap and a custom-made porous polyethylene implant. She was thereafter treated with developmental stage glass fiber-reinforced composite - bioactive glass implant. After two years and three months, the implant was removed due to an implant site infection. The implant was analyzed histologically, mechanically, and in terms of chemistry and dissolution of bioactive glass. Mechanical integrity of the load bearing fiber-reinforced composite part of the implant was not affected by the in vivo period. Bioactive glass particles demonstrated surface layers of hydroxyapatite like mineral and dissolution, and related increase of pH was considerably less after two and three months period than that for fresh bioactive glass. There was a difference in the histology of the tissues inside the implant areas near to the margin of the implant that absorbed blood during implant installation surgery, showed fibrous tissue with blood vessels, osteoblasts, collagenous fibers with osteoid formation, and tiny clusters of more mature hard tissue. In the center of the implant, where there was less absorbed blood, only fibrous tissue was observed. This finding is in line with the combined positron emission tomography - computed tomography examination with (18F)-fluoride marker, which demonstrated activity of the mineralizing bone by osteoblasts especially at the area near to the margin of the implant 10 months after implantation. Based on these promising reactions found in the bioactive glass containing fiber-reinforced composite implant that has been implanted for two years and three months, calvarial reconstruction with the presented material appears to be a feasible method.

Preparation of antibacterial and radio-opaque dental resin with new polymerizable quaternary ammonium monomer.

OBJECTIVE: A new polymerizable quaternary ammonium monomer (IPhene) with iodine anion was synthesized and incorporated into Bis-GMA/TEGDMA (50/50, wt/wt) to prepare antibacterial and radio-opaque dental resin. METHODS: IPhene was synthesized through a 2-steps reaction route, and its structure was confirmed by FT-IR and (1)H-NMR spectra. IPhene was incorporated into Bis-GMA/TEGDMA (50/50, wt/wt) with a series of mass fraction (from 10 wt.% to 40 wt.%). Degree of monomer conversion (DC) was determined by FT-IR analysis. Polymerization shrinkage was determined according to the variation of density before and after polymerization. The flexural strength, modulus of elasticity, and fracture energy were measured using a three-point bending set up. Radiograph was taken to evaluate the radio-opacity of the polymer. A single-species biofilm model with Streptococcus mutans (S. mutans) as the tests organism was used to evaluate the antibacterial activity of the polymer. Bis-GMA/TEGDMA resin system without IPhene was used as a control group. RESULTS: FT-IR and (1)H-NMR spectra of IPhene revealed that IPhene was the same as the designed structure. ANOVA analysis showed that when mass fraction of IPhene was more than 10 wt.%, the obtained resin formulation had lower DC, polymerization shrinkage, FS, and FM than control resin (p<0.05). Polymers with 20 wt.% and 30 wt.% IPhene had higher fracture energies than control polymer (p<0.05). IPhene containing samples had higher radio-opacity than control group (p<0.05), and radio-opacity of IPhene containing sample increased with the increasing of IPhene mass fraction (p<0.05). Only polymers with 30 wt.% and 40 wt.% of IPhene showed antibacterial activity (p<0.05). SIGNIFICANCE: IPhene could endow dental resin with both antibacterial and radio-opaque activity when IPhene reached 30 wt.% or more. Though sample with 30 wt.% of IPhene had lower FS and FM than control group, its lower volumetric shrinkage, higher fracture energy, higher radio-opacity, and antibacterial activity still made it having potential to be used in dentistry.