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Polymer fibers are used for a wide range of materials in contact with the human body. Since bacterial contamination may cause diseases, it is desirable to provide fibers with antimicrobial properties. This work investigates the ability of siIver-tricalcium phosphate nanoparticles (Ag/TCP) to build a reactive system when incorporated in polyamide fibers. In the presence of bacteria, the TCP carrier particles are biodegraded and trigger the release of silver. For this work, Ag/TCP nanoparticles (1.3 wt% silver) were produced by flame spray synthesis and subsequently processed with polyamide 6 to fibers (125-µm thick, containing 260 ppm silver) with the aid of extrusion and melt-spinning for subsequent antibacterial testing. The fibers were contaminated with the clinically relevant strains Escherichia coli or Streptococcus sanguinis, respectively. The reactive fibers demonstrated significantly reduced plate count within 24 h (the number of colony forming units was reduced by 99.999% with E. coli and 99.6% with S. sanguinis compared with pure PA6 reference fibers). These reactive properties of easily integrated antibacterial silver suggest an implementation of intelligent fibers to a wide range of applications. POLYM. ENG. SCI., 51:71-77, 2011. [C]2010 Society of Plastics Engineers, INTRODUCTION Synthetic fibers - industrial and commercial - are omnipresent. In 2002, the global production of manufactured fibers was 36 million metric tons: Fiberglass pads build modern cars, polyesters form [...]

Treatment of bone defects generally requires a fixation device. Biodegradable implants can often prevent second operations in contrast to metallic implants that are surgically removed after healing. In this study, we investigate the preparation of a bone fixation device with additional bioactivity by adding nanoparticulate amorphous tricalcium phosphate (ATCP) to improve bonding to bone. Medically approved poly(lactide-co-glycolide) (PLGA) and spherical (ATCP) nanopar-ticles were blended directly or through a two-step approach, where ATCP was first dispersed in PLGA by solvent casting, extruded and hot pressed producing blocks and bone screws. The latter route yielded good particle dispersion while blending alone led to inhomo-geneous mixtures. Samples were immersed in simulated body fluid and showed rapid formation of surface hydroxy apatite layers (examined by X-ray diffraction and scanning electron microscopy) already after 3 days, thus confirming very high bioactivity. Polymer degradation during processing and upon simulated implantation conditions was followed by gel permeation chromatography. The elevated temperature during extrusion was the strongest single factor contributing to PLGA degradation. Screws could be machined out of extruded cylinders and demonstrated the ability to process PLGA/ATCP 90/10 composites with regular workshop tools. These properties suggest the use of such composites as improved, bioactive, and degrad-able bone fixation systems particularly in oral and maxillofacial surgery. POLYM. ENG. SCI., 50:952-960, 2010. [C] 2009 Society of Plastics Engineers, INTRODUCTION Biomedical composites are used in temporal or permanent implant materials and they have gained significant clinical interest due to their ability to integrate into the body (l-3). The advantage [...]

Purpose: To determine the influence of the relative enamel abrasivity (REA) of fluoridated toothpaste on the uptake of KOH-soluble and structurally bound fluoride into enamel. Materials and Methods: Bovine enamel samples were randomly allocated to 6 groups (n = 36 per group). Groups A to C were treated with sodium fluoride (NaF) toothpastes and groups D to F with amine fluoride (AmF) toothpastes (1500 ppm F each). The REA in groups A and D was 2, in groups B and E it was 6 and in groups C and F it was 9. Twice a day, 18 samples of each group were immersed for 2 min in a slurry (toothpaste:artificial saliva = 1:3), while the remaining samples were brushed with the respective slurry (2.5 N force; 60 strokes/min; 2 min). All samples were stored at 37°C and 100% humidity. After five days, the amount of KOH-soluble and structurally bound fluoride was determined and statistically compared by Scheffe's post-hoc tests. Results: REA value and mode of application (immersion or brushing) had no significant influence on the amount of either kind of fluoride from NaF toothpastes. Only for the NaF toothpaste with REA 6 was the amount of KOH-soluble fluoride significantly higher after brushing. With AmF toothpastes, KOH-soluble and structurally bound fluoride concentrations were significantly higher when the samples were brushed. Furthermore, in the REA-2 group, the amounts of KOH-soluble fluoride (brushed or immersed) and structurally bound fluoride (brushed) were significantly higher than in the other groups. Conclusion: The REA dependency of KOH-soluble and structurally bound fluoride was found only for the AmF toothpastes. Using AmF toothpaste, the mode of application influenced the uptake of KOH-soluble and structurally bound fluoride into enamel. [ABSTRACT FROM AUTHOR]

Purpose: A low direct current can be used to disinfect dental titanium implants in simulated physiologic environments. The aim of this study was to determine whether this treatment affects implant surface structure and cytocompatibility. Materials and Methods: Titanium test disks with a sandblasted, acid-etched, large-grit (SLA) surface were placed as anodes in an electrolytic bath with physiologic saline and treated with 15 mA of current for 15 minutes. Surfaces were analyzed by light and electron microscopy and contact angle measurement. Depth profile analyses of SLA disks were run at subsurface levels from 0 to 1,000 nm. The proliferation and viability of preosteoblastic cells and human foreskin fibroblasts on implant surfaces were assessed. Alkaline phosphatase (ALP) activity was determined with and without exposure to bone morphogenetic protein-2 (BMP-2). Mineralization was determined after 4 weeks. Results: A blue discoloration was observed after treating the SLA disks, but no damage was recognized microscopically. An oxidation layer formed on the surface and the wettability of the disks increased significantly. Cell proliferation and initial maturation were not affected by the treatment. Mineralization and ALP activity of BMP-exposed cells, however, were slightly but significantly reduced on test disks. Conclusions: The current study showed that the alterations in implant color after electrochemical treatment did not reflect significant surface changes, which would preclude cell adhesion and growth or have a major impact on osteoblastic differentiation or maturation. [ABSTRACT FROM AUTHOR]

Objectives: Polyvinylpyrrolidone-iodine (PVP-iodine or povidone-iodine) enhances the treatment outcomes of initial periodontal treatment but the degree of benefit varies in the literature. A main reason might be the concentration of the dosage form and its contact time with the periodontal tissues. In this randomized pilot study the effect of repeated subgingival application of PVP-iodine during scaling and root planing (SRP) was assessed. Changes of clinical parameters and microbiotic taxa after 3 months were analyzed. Method and Materials: In a split-mouth design 12 patients with generalized, severe periodontitis were treated with SRP combined with subgingival application of either PVP-iodine or water. Test and control sides were isolated with a special rubber dam technique. Irrigations were reapplied during SRP. Periodontal probing depth (PD) and recessions were documented before treatment and after 3 months. Samples of subgingival bacteria before SRP and after 1 week, 1 month, and 3 months were analyzed. Results: Three months after SRP, changes for PD and recession in deep pockets were significantly higher in the PVP-iodine group (P = .012 and .044 respectively). The number of these pockets was reduced from 73 at baseline to 8 in the test and 19 in the control group. In both groups, bacterial taxa were reduced after 1 week. One month after SRP only taxa of Porphyromonas gingivalis in the PVP-iodine group were lower than at baseline. After 3 months, all taxa regained baseline values. Conclusion: PVP-iodine reapplied frequently during SRP might enhance pocket depth reduction in initially [ABSTRACT FROM AUTHOR]

This retrospective study aimed to radiographically assess sinus floor remodeling after using a modified osteotome technique without graft materials or membranes. After pilot drilling, residual bone was fractured and raised with the schneiderian membrane to the final implant length using osteotomes. Self-tapping implants were placed, and restorations were placed 6 months later. Twenty-four patients were available for follow-up after a mean observation period of 17.6 ± 8.4 months. The implant survival rate at that time was 100%. Bone filling around the implants was measured and compared with baseline digital radiographs. New bone formation was 86.3% ± 22.1% mesially and 89.7% ± 13.3% distally. In nine cases, digital volume tomography was used to verify regeneration. Within the limitations of this study, use of the schneiderian membrane led to considerable bone regeneration, and good clinical success was achieved despite the omission of graft materials. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of CO2 laser treatment through topically applied amine fluoride solution on demineralised enamel.Materials and Methods: Sixty extracted human molar crowns were selected and cut longitudinally into half. One half was subjected to a 10-day pH-cycling procedure to create caries-like lesions, whereas the other was left non-demineralised. The following treatments were randomly assigned (one treatment per tooth, on respective non-demineralised and demineralised matched specimens): exposure to a 1% amine fluoride solution for 15 s without irradiation (group I), irradiation for 15 s with a continuous-wave CO2 laser (group II), or laser-treatment for 15 s through the amine fluoride solution applied immediately beforehand (group III). Fluoride uptake (n = 30) and acid resistance (n = 30) were determined after treatment. Enamel surface alterations after laser irradiation were monitored using scanning electron microscopy.Results: In groups I and III, an increased fluoride uptake was detected (p < or = 0.05). Laser irradiation through topical fluoride resulted in an increased acid resistance of sound and demineralised enamel specimens in deeper layers (p < or = 0.05). In addition, less surface alterations were observed in SEM examination of specimens irradiated through the amine fluoride solution compared with counterparts treated with laser only.Conclusions: CO2 laser light application through an amine fluoride solution may be instrumental in enhancing acid resistance of sound and demineralised enamel. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate bonding penetration into different enamel substrates. Materials and Methods: Ten extracted human molars were mesiodistally sectioned. Buccal and lingual enamel surfaces were divided into four equal areas using sticky wax. The central two areas of each tooth (n = 20) were demineralized for 12 weeks using an acidic gel (pH 4.8). The lateral areas served as controls. After demineralization, ten specimens were remineralized in a saliva substitute for three weeks. An amine fluoride solution (Elmex Fluid) was applied on one half of each specimen before acid etching. After etching for 120 s, an enamel-bonding agent (Heliobond) containing 0.1% rhodamine was applied onto test and control areas, and was light cured for 60 s. Subsequently, the specimens were sectioned and tag length was determined using a confocal laser scanning microscope (CLSM). Results were statistically compared with ANOVA followed by Scheffe's and Bonferroni/Dunn post hoc tests. Results: With a mean penetration depth of 68 ± 22 μm, tags in demineralized enamel were significantly longer than in other groups (p ≤ 0.01). Penetration decreased significantly in remineralized areas or when fluoride was used (p ≤ 0.01), but was still significantly deeper than in control sites (p ≤ 0.01). Conclusion: Penetration of an unfilled resin into enamel was considerably influenced by the degree of dental hard tissue mineralization. Penetration was increased in demineralized enamel; however, remineralized enamel also allowed good penetration of the bonding agent. [ABSTRACT FROM AUTHOR]

A newly developed prophylaxis paste that contains perlite as an abrasive medium (Cleanic) was compared to conventional prophylaxis pastes with regard to relative dentin and enamel abrasion, cleaning ability, and polishing power. Rubber cups and nylon brushes were used as paste carriers. Water, flour of pumice, and the dentin polishing paste CCS 40 served as controls. The tested prophylaxis pastes, selected according to their popularity among clinicians, were CCS 250, Détartrine Z, Nupro Coarse, and Zircate. The Prophylaxis Paste Index was created to assess the clinical potential of the various prophylaxis pastes more accurately. The Index was computed for dentin as cleaning ability dended by relative dentin abrasion x surface roughness (in Ra) x 10, and for enamel as cleaning ability dended by relative enamel abrasion x surface abrasion (in Ra). On dentin and enamel, Cleanic consistently yielded low relative dentin and enamel abrasion values, a good cleaning ability, and low surface roughness scores with both rubber cups and nylon brushes. Of all tested prophylaxis pastes, Cleanic excelled in the Prophylaxis Paste Index on dentin and enamel and with both rubber cup and nylon brush applications. Therefore, a perlite-containing prophylaxis paste has broad professional therapeutic indications and may be used universally as a single paste to clean and polish both dentin and enamel. [ABSTRACT FROM AUTHOR]

An ideal prophylaxis paste should have both cleaning and polishing properties. Key elements would be abrasive particles that become less aggressive under load. The abrasive perlite, a volcanic glass with a sheet-like geometry, is claimed to have these unique properties. This study evaluated the average particle size, size distribution, and morphology of perlite in raw form, in an unused prophylaxis paste, and a used prophylaxis paste. The surface roughness induced on enamel and dentinal specimens was quantitated after paste application in either a rubber cup or a nylon brush. Flour of pumice, a standard prophylaxis paste, a polishing paste, and water were tested similarly. The luster induced by the tested pastes and controls was assessed. Perlite blunted and disintegrated under load. The perlite-containing prophylaxis paste acted as a fine or superfine prophylaxis paste, although it was ranked as medium, based on the mean particle size of its abrasive in the fresh, unused form. Perlite might provide the properties required for the abrasive material of an ideal prophylaxis paste. [ABSTRACT FROM AUTHOR]