Faculty Bibliography

PURPOSE: The aim of this study was to investigate the cellular response of human gingival fibroblasts (HGFs) cultured on smooth or rough zirconia (Zr) or titanium (Ti) disks. MATERIALS AND METHODS: Disks fabricated from four different materials--smooth Zr (Zr-S), rough Zr (Zr-R), smooth Ti (Ti-S), and rough Ti (Ti-R)--were used, and surface roughness was analyzed by atomic force microscopy. After HGFs were cultured on these disks, cell morphology was examined by scanning electron microscopy, cell proliferation activity was evaluated by a monotetrazolium assay, and gene expression levels of various collagens and integrins were measured by real-time polymerase chain reaction. RESULTS: The Ti-R disks were the roughest, followed by Zr-R, Ti-S, and Zr-S, in that order. The cells cultured on the Zr-S and Ti-S disks appeared to be more aligned with the fine irregularities at later time points, whereas the cells cultured on the Zr-S showed the weakest spreading compared to the other surfaces after 3 hours of culture. With respect to proliferation, cells proliferated significantly faster on the Zr-S surface than on the other surfaces. Gene expression of integrin alpha2 at 3 hours and integrin alpha5 and type I collagen at 48 hours on Zr-S was significantly up-regulated compared to Ti. Conversely, the expression of integrins beta1 and beta3 and type III collagen was significantly decreased on Zr-S at 1 hour compared to the other materials. CONCLUSION: These data indicate that different surface materials and topographies may induce a distinct HGF morphology, proliferation, and gene expression.

Objectives: The purpose of the present study was to investigate the early peri-implant soft tissue healing on different titanium surface topographies. Material and methods: Titanium implants with smooth or rough surfaces were placed in the extraction site at 1 month after the maxillary first molar extractions of 15 male Sprague-Dawley rats. At 4 and 7 days after implant surgery, the peri-implant oral mucosa was randomly harvested and analyzed for collagen fiber orientation, and expression of extracellular matrix genes. Descriptive and paired t-tests were performed where appropriate (alpha=0.05). Results: The laser scanning microscopic analysis of the Sirius red stained peri-implant connective tissue revealed a parallel and uniform collagen fiber orientation along the smooth implant at both 4 and 7 days. In contrast, the collagen fibers of the comparative peri-implant tissue from rough surface implants at 7 days were not arranged in parallel orientation but in an irregular a 'cotton-ball-like.' The levels of mRNA of types III and XII collagen and transforming growth factor-beta1 significantly increased in the smooth implant group compared with the rough implant group at both 4 and 7 days or either one of days. Conclusion: The results of this study suggest that implant surface characteristics may affect early events of soft tissue healing by influencing collagen fiber orientation and expression of key genes for initial healing. To cite this article: Yamano S, Al-Sowygh ZH, Gallucci GO, Wada K, Weber H-P, Sukotjo C. Early peri-implant tissue reactions on different titanium surface topographies. Clin. Oral Impl. Res. xx, 2010; 000-000

The HIV-1 Tat peptide has been successfully used for intracellular gene delivery. Likewise, various lipid-based methods have shown increased endocytosis and can influence endosomal escape. This study combines the favorable properties of Tat peptide with that of lipid systems for DNA delivery. We combined the lipid FuGENE HD (FH) with the Tat peptide sequence modified with histidine and cysteine residues (mTat). mTat/FH transfection was evaluated by luciferase expression plasmid in five cell types. mTat/FH produced significant improvement in transfection efficiency of all cell lines when compared to FH or mTat. Treatment with chloroquine, associated with energy-dependent endocytosis, significantly increased transfection efficiency with mTat/FH while incubation at low temperature decreased it. The zeta potential of mTat/FH/DNA was significantly higher compared to FH, mTat, or their DNA combination in the presence of serum, and it was correlated with transfection efficiency. The particle size of the FH/DNA complex was significantly reduced by addition of mTat. Filipin III, an inhibitor of caveolae-mediated endocytosis, significantly inhibited mTat/FH transfection, but transfection was increased by chlorpromazine, an inhibitor of clathrin-mediated endocytosis. These findings demonstrated the feasibility of using a combination of mTat with lipids, utilizing temperature-dependent and caveolae-mediated endocytosis, as a potentially attractive non-viral gene vector

The objective of this study was to evaluate the ability of a collagen membrane (CM) as a carrier to successfully deliver platelet-derived growth factor (PDGF) and to observe the subsequent effects of the factor on preosteoblasts in vitro. MC3T3-E1 mouse preosteoblasts were cultured with a commercially available CM containing PDGF. After a two-day cell culture, cell viability was investigated by the MTT assay and cell proliferation was assessed by the crystal violet proliferation assay. Expression levels of the following osteoblastic differentiation marker genes were measured by real-time PCR: runt-related transcription factor 2 (RUNX2), osteopontin (OPN), bone sialoprotein (BSP), and osteocalcin (OCN). A cell proliferation assay was conducted, and osteoblastogenesis was determined by alkaline phosphatase (ALP) activity. A sustained release of PDGF from a CM was observed for ~3 weeks. Gene expression of all RUNX2, OPN, BSP, and OCN in CM with PDGF was significantly upregulated compared to those in CM without PDGF (all p < 0.05). Interestingly, CM without PDGF also significantly increased gene expression of RUNX2 and OPN in MC3T3-E1 cells compared to the cell control (both p < 0.05). Furthermore, it was observed that the PDGF released from CM significantly promoted ALP activity and cell proliferation with little cytotoxicity. These results suggest that a CM can be utilized for sustained delivery of PDGF. Also, released PDGF can promote MC3T3-E1 cell activities. This strategy may lead to an improvement in the current clinical treatment of bone defects in periodontal and implant therapy

Abstract Background: While many studies have focused on the hazardous effects of smoking, there is little direct evidence regarding the specific detrimental effects of the nicotine on the osseointegration of implants. Objective: To understand the effects of nicotine on gene expression and osseointegration of titanium implants in rats. Material and methods: Forty-four rats were administered with nicotine or saline for a period of 8 weeks. The femurs were then harvested and analyzed using a three-point bending test. Osseointegration level was determined using bone/implant contact ratio at 2 or 4 weeks after implants were placed. Expression levels of bone matrix-related genes were measured by quantitative real-time polymerase chain reaction. Results: The results of the three-point bending showed that there was no significant difference detected in stiffness between control and nicotine groups at 8 weeks post-saline/nicotine delivery (P=0.705). The bone/implant contact ratio in nicotine-delivered group was significantly decreased compared with those in the control group at 4 weeks (P<0.05). Also, expression levels of osteopontin, type II collagen, bone morphogenic protein-2, bone sialoprotein, and core-binding factor alpha-1 were significantly down-regulated in the nicotine-delivered group compared with the control. Conclusions: Although systemic exposure to nicotine did not affect rat bone development, bone wound healing around the implant after placement was affected. These findings suggest that nicotine might inhibit the bone matrix-related gene expressions required for wound healing and thereby diminish implant osseointegration at late stage. To cite this article: Yamano S, Berley JA, Kuo WP, Gallucci GO, Weber HP, Sukotjo C. Effects of nicotine on gene expression and osseointegration in rats. Clin. Oral Impl. Res. xx, 2010; 000-000. doi: 10.1111/j.1600-0501.2009.01955.x

This study compared six commercially available reagents (Arrest-In, ExpressFect, FuGENE HD, jetPEI, Lipofectamine 2000, and SuperFect) for gene transfection. We examined the efficiency and cytotoxicity using nine different cell lines (MC3T3-E1 mouse preosteoblasts, PT-30 human epithelial precancer cells, C3H10T1/2 mouse stem cells, MCF-7 human breast cancer cells, HeLa human cervical cancer, C2C12 mouse myoblasts, Hep G2 human hepatocellular carcinoma, 4T1 mouse mammary carcinoma, and HCT116 human colorectal carcinoma), and primary cells (HEKn human epidermal keratinocytes) with two different plasmid DNAs encoding luciferase or beta-galactosidase in the presence or absence of serum. Maximal transfection efficiency in MC3T3-E1, C3H10T1/2, HeLa, C2C12, Hep G2, and HCT116 was seen using FuGENE HD, in PT-30, 4T1, and HEKn was seen using Arrest-In, and in MCF-7 was seen using jetPEI. Determination of cytotoxicity showed that the largest amount of viable cells was found after transfection with jetPEI and ExpressFect. These results suggest that FuGENE HD is the most preferred transfection reagent for many cell lines, followed by Arrest-In and jetPEI. These results may be useful for improving nonviral gene and cell therapy applications

Abstract The purpose of this study was to determine whether high levels of plasma nicotine, delivered via subcutaneously placed mini-osmotic pumps, had an effect on bone development and osseointegration of a titanium implant in rat femurs in both the short and long term. In this study, we hypothesized that systemic nicotine may not affect bone development, but may affect osseointegration in both the short and long term. Thirty rats were assigned to 4 groups. Group 1 (n = 10) was subdivided into 2 groups, which both received nicotine during the duration of the experiment. Half of the group (n = 5) was sacrificed at 2 weeks after implant placement, and the other half (n = 5) was sacrificed at 4 weeks after implant placement. Group 2 (n = 10) was treated identically; however, this group was given saline placebo rather than nicotine. Nicotine/saline was administered via subcutaneous mini-osmotic pumps. Serum analysis was assessed biweekly and weight was assessed weekly. Implant placement consisted of mini-implant placement in the femur of the rats under general anesthesia. After sacrifice, the femurs were harvested and analyzed. Biomechanical push-in test was used to determine the degree of osseointegration by evaluating the breakpoint load. Micro-CT was performed on the femurs of the remaining 10 rats to determine the bone density and architecture. Micro-CT showed no significant difference in bone morphometric analysis. Push-in test showed significant difference in axial load force required to dislodge the implant between the nicotine-treated and control rats both at 2 and at 4 weeks after implant placement. The evidence indicates that while there was no significant difference in bone development and remodeling with exposure to systemic nicotine, there was a significant difference in bone wound healing, specifically with the osseointegration of titanium implants at both 2 and 4 weeks after implant placement. In conclusion, systemic nicotine may have a significant impact on the osseointegration of implants in the rat femur. Additional studies need to be conducted to further understand the specific way in which nicotine adversely affects wound healing on the molecular level

Abstract This clinical report describes the oral rehabilitation of a 15-year-old male patient who was involved in a snowmobile accident and suffered multiple mid-face and mandibular fractures. Consequences of the accident included avulsion of teeth numbers 5 to 10 and 21 to 26, and a significant amount of maxillary and mandibular anterior alveolar bone loss. The patient underwent open reduction and rigid fixation of the fractured left zygoma, comminuted LeFort I maxillary fracture, and left body of the mandible; closed reduction of the bilateral condylar fractures; autologous corticocancellous bone grafting to the maxilla and mandible; implant placement; and prosthesis fabrication. This multidisciplinary approach successfully restored function and esthetics