Volume 34, Issue 3 - Special issue: Biomaterials for dental technologies / Issue editor: Shih-Jung Liu

The aim of the study was to investigate the efficacy of the addition of funoran to xylitol chewing gum in dental plaque. In a double-blinded randomized controlled clinical trial, 36 health adults (21–30 years old), who volunteered after informed consent, with >10 5 colony-forming units/ml mutans streptococci (MS) at baseline, were assigned randomly into one of three parallel study groups: xylitol+funoran gum (group A), sucrose gum group (group B), and control group (no gum have been provided; group C). The pH value, flash weight, and MS of dental plaque were recorded at baseline and after 2 weeks of treatment. A statistically significant reduction (p<0.05) of salivary MS was displayed in group A after the intervention when compared with baseline. The weight of plaque was reduced after 2 weeks of treatment (p=0.032) in group A. There was no significance in plaque pH value before and after the treatment in any group. Daily funoran-containing xylitol chewing gum application significantly reduced the dental plaque volume and caries pathogen counts in the oral cavity, suggesting that the use of funoran-containing xylitol chewing gum may be a useful adjunct for caries control.

The traditional orthodontic power chain, usually made of polymer materials, exists some drawbacks, such as the reduction of elasticity due to swell after absorbing water and surface discoloration resulting from the patient’s diet, food, or beverage colors leading to poor appearance. The main purpose of this study was to develop surface modification on orthodontic power chain and to realize the properties change for improvement of its shortcomings. In this study, a template was produced by pure aluminum piece with anodized production (concave) through the nanoimprinting process fabricating nanostructures (convex) on the surface of power chain, resulting in surface modification of power chain. The different nanoimprinting process parameters (e.g., imprinting temperature, imprinting pressure, imprinting time, and demolding temperature) were used to produce nanostructures on the surface of power chain. The results of this study show that the contact angle of the power chain became larger after nanoimprinting surface treatment. The hydrophilic properties of power chain have been turned into hydrophobic properties. Unmodified power chain before water absorption is about 4%, while a modified water absorbance is about 2%–4%.

The naturally occurring isoprene rubber component of gutta-percha has been used in dental root canal filling treatments for almost a hundred years owing to its stability and plasticity as a root canal filling material. The traditional warm gutta-percha vertical compaction technique is the major technique for warm gutta-percha root canal obturation. However, the relation between compaction force and temperature change in this technique is still unclear. The purposes of this study were to determine the ideal gutta-percha molding temperature for compaction and to evaluate single and double heating and compaction in the warm vertical compaction procedures using infrared thermography. Gutta-percha was placed in a digital dry bath incubator at temperatures ranging from 25°C to 62°C in order to analyze compaction forces using an Instron universal testing machine. Both single and double heating and compaction procedures were examined using an infrared thermograph model to monitor temperature change when performing the warm gutta-percha vertical compaction procedure. Our results demonstrate that 44–58°C is the ideal temperature to soften gutta-percha for excellent compaction. Heating and compacting gutta-percha twice at 3 mm from the apex can mold the gutta-percha completely.

The aim of this study was to compare different bone grafting materials and their contribution to socket preservation. In six beagle dogs, bilateral mandibular second, third, and fourth premolars were hemisectioned and extracted. The following four treatment modalities were randomly allocated: (1) empty control site, (2) collagen plug, (3) Bio Oss-collagen, (4) HA/β-TCP-collagen. After 2 and 4 weeks, the animals were sacrificed, and decalcified sections were obtained for histological analysis. New bone formation was homogeneous, progressive, and centripetal in all materials. Remodeling as well as the calcification of the newly formed bone was observed. In addition, well-connected trabeculae surrounding the degraded materials were observed. Nearly mature bone, which demonstrated less cellular, more mineralized, and structurally more organized into lamellar bone was noted in HA/β-TCP-collagen composite. In this study, Bio Oss-collagen and HA/β-TCP-collagen produced a newly biomimetic composite biomaterial and could prove to be a superior bone substitute material, both structurally and functionally, which could be used in the repair of bone defects collagen composite.

Polylactic acid (PLA)-based composite has been widely used in tissue engineering. To modify the material’s properties, inorganic substances have been used to form nanoparticle-PLA composites. The aim of this study is to develop a novel magnetic biodegradable composite. Nanoscale magnetite (Fe 3 O 4 ) was incorporated into a poly-L-lactide (PLLA) matrix with proportions of 0%, 5%, 10%, and 15% (w/w). Injection molding was carried out to produce the nano-magnetite-PLLA composite samples. X-ray diffraction (XRD), differential scanning calorimetry (DSC), superconducting quantum device (SQUID), and three-point bending were performed to test the physical properties of the magnetite-PLLA composite. The results showed that the magnetite-PLLA composite exhibited typical ferromagnetic hysteresis loops. The addition of nanoscale magnetite significantly increased the magnetic flux density of the PLLA composite. These results suggest that the magnetite-PLLA composite has the potential to be used for future applications in tissue engineering.

Guided tissue regeneration (GTR) in the management of the periodontal furcation invasion is effective. Recent studies showed significant clinical improvement with different materials. The purpose of this study is to provide clinical evaluations of the bone repair potential of GTR combined with a novel porcine collagen membrane in the treatment of human molar Class II furcations. Fifty-one patients, 33 males and 18 females, with no systemic disease and a mean age of 49.1 years, participated in this study after phase I periodontal therapy. Probing depth, attachment loss and radiographic examination were recorded and analyzed before and after GTR therapy with collagen membrane. In the soft tissue measurement, the periodontal pocket (PD) depth was 5.283±0.283 mm before the surgery and improved to 2.631±0.147 mm at 9 months after surgery (p<0.05). Attachment loss also showed similar results. The attachment level was 5.547±0.3 mm before the surgery, and 2.911±0.188 mm at 9 months after surgery (p<0.05). According to the measurements the attachment gain was 2.636±0.168 mm after GTR surgery with porcine collagen membrane. According to this study, the porcine collagen membrane can perform with exceptional results in attachment level gain for the Class II periodontal furcation involvement.

The aim of this study was to develop an electrospun poly- l -lactide (PLLA) nanofibrous membrane incorporating oleic acid-coated Fe 3 O 4 . The Fe 3 O 4 nanoparticles were prepared using the chemical co-precipitation method, and particle diameters were analyzed using transmission electron microscopy. After mixing the oleic acid-coated Fe 3 O 4 nanoparticles and PLLA, a membrane with nanofibers was manufactured using the electrospinning technique. Our results showed that Fe 3 O 4 nanoparticle diameters fabricated in this study were concentrated at 2–8 nm (84.2%). After magnetizing, there exists an approximately linear relationship between magnetic flux density and membrane thickness (R 2 =0.7, p<0.05). NIH-3T3 fibroblast cells cultured on the magnetized Fe 3 O 4 /PLLA nanomembranes exhibited a more spreading and attached phenotype. These results can serve as a reference for future advanced studies.

In the present study, a nanoporous, biocompatible titanium dioxide (TiO 2 ) film was formed on the surface of titanium, using oxygen plasma immersion ion implantation (OPIII), and the influence of this film on the bio-functionalization, including the proliferation and differentiation properties of MG-63 osteoblast-like cells, was analyzed and investigated. The OPIII-treated surface was characterized by X-ray photoelectron, which showed that a TiO x layer was formed on Ti substrates. This TiO x surface exhibited nanoscale surface roughness in the form of nanoporous structures. The results also revealed that MG-63 cells expressed increased proliferation on the OPIII-treated surface as compared with the untreated Ti substrate. The Ti specimens treated with plasma energy of 1 kW revealed better expression of alkaline phosphatase (ALP) activity and showed higher average surface roughness than untreated specimens. Thus, it can be concluded that bioactivity of Ti implants can potentially be improved by OPIII.

In the present study, nanocrystalline diamond (NCD) nanowire films were synthesized on silicon substrates, using microwave plasma-enhanced chemical vapor deposition (PECVD) with a CH 4 /Ar/N 2 gas mixture at moderate temperatures. The influence of nitrogen concentration on the formation of NCD was investigated. The characteristics of NCD films were evaluated using scanning electron microscopy (SEM), Raman spectroscopy, optical emission spectroscopy (OES), and a contact angle meter. NCD nanowire films with 300–500 nm length were grown with the incorporation of nitrogen. Heterostructures of sp 3 -bonded diamond nanowires and sp 2 -bonded graphite were synthesized by adding small amounts of nitrogen to the CH 4 /Ar gas mixture. Surface roughness became smooth and the grain size decreased as the nitrogen was introduced into the CH 4 /Ar gas mixture. With the increase of nitrogen concentration, the sp 2 /sp 3 ratio of carbon bonds increased. The wettability of the NCD nanowire films was sensitive to the bonding structure. The hydrophobic and non-reactive properties of NCD nanowire films make them highly applicable for biomedical implants.

Chemotaxis of cancer cells is an essential component of tumor dissemination. The chemotactic response is comprised of three separate steps, including chemosensing, polarization and locomotion. We present an innovative approach on chemotaxis assay to address cancer cell chemotaxis. We applied a high-resolution optical tweezers system to manipulate epidermal growth factor (EGF)-coated beads positioned close to the filopodia, to locally stimulate HT29 cells expressing the EGF receptor (EGFR). We demonstrated that membrane protrusion at the leading edge induced by an EGF chemotaxis occurred at about 30∼40 s. In addition, the present observation revealed that the locomotion of HT29 cell depended on whether the HT29 cell sensed the presence of the chemoattractant EGF. We anticipate the proposed approach based on optical tweezers, together with the platform at single-cell level, could be applied to build a quick screening method for detection and treatment evaluation of many types of cancer during chemotaxis.

X-ray computed tomography (CT) is one of the most powerful non-invasive diagnostic techniques nowadays. The iodinated molecules used as CT contrast agents in the clinic have short circulation times in the body, which significantly restrict its applications. Furthermore, some patients are hypersensitive to iodine. So, researchers have made tremendous efforts to improve the property of iodine. Besides, cis-diammineplatinum (II) dichloride (cisplatin), a major chemo agent for cancer treatment, possess higher X-ray attenuation coefficient being a CT contrast agent. The incorporation of cisplatin with an iodinated agent could facilitate the quality of CT images and damage cancer cells simultaneously. To reduce toxicity of a contrast agent, polymer matrix, gelatin, was incorporated for avoiding contact with nontarget cells. In this study, we combined the iodine contrast agent, 1,3-N-bis (2,3-dihydroxypropyl)-5-[N-(2,3-dihydroxypropyl)acetamido]-2,4,6-triiodobenzene-1,3-dicarboxamide (iohexol), with cisplatin, and then examined them in a micro CT with different X-ray tube voltages (50 kV, 80 kV, 100 kV) to find optimal scanning conditions for imaging. As expected, iohexol combined with cisplatin enhanced X-ray attenuation and image contrast. The optimal CT image could be acquired at iohexol and cisplatin concentrations of 50 mg/ml and 3 mg/ml, respectively, under 80 kV irradiation. Finally, the iohexol-cisplatin-gelatin solution was then fabricated into nanoparticles of sizes about 240 nm, which may suitable for in vivo delivery.

Devices based on semiconducting nanowires (NWs) are functioning as highly sensitive and selective sensors for the label-free detection of biological and chemical species. This paper demonstrates a novel back-gated silicon NW field effect transistor (NWFET) for gene detection. The fabricated NWFET was employed as the biomolecule sensor for the early, real-time, and label-free screening of hepatitis B virus (HBV) X gene. The DNA fragment in HBV demonstrates the linearity from 10 fM to 1 pM, of which the detection limit is estimated to be about 3.2 fM. The obtained results also show that the NW-based sensor can distinguish the difference between the complementary and 1-base mismatch DNA. The back-gated NW FET exhibits a label-free, highly sensitive, and selective biosensor for gene detection, which also provides a possibility of multiple chemical and biological species detection with sensor array in an integrated chip.