Behavior Of Gingival Fibroblasts Research Articles

Photothermal modulation of gingival fibroblasts via polydopamine-coated zirconia: A novel approach for promoting peri-implant soft tissue integration

Achieving robust soft tissue integration around dental implants is crucial for long-term clinical success, as it forms a protective biological seal against bacterial invasion. However, the soft tissue attachment to implants is relatively deficient compared to natural teeth, particularly in the connective tissue region lacking sufficient gingival fibroblasts and collagen fiber alignment. This study proposed an innovative strategy to enhance peri‑implant soft tissue integration by modulating gingival fibroblast behavior via photothermal conversion. Zirconia surfaces were coated with polydopamine (PDA), a melanin-like polymer exhibiting near-infrared (NIR) absorption for photothermal conversion. Under NIR irradiation, the PDA coating enabled mild hyperthermia (42–43 °C) on the zirconia surface. Remarkably, this mild photothermal stimulation significantly promoted human gingival fibroblast proliferation, adhesion, and collagen production compared to unmodified zirconia in vitro. By utilizing the photothermal properties of PDA coatings to modulate cellular behaviors beneficial for connective tissue formation, this approach provides a promising avenue to achieve improved soft tissue integration and long-term stability of dental implants. The findings highlight the innovative potential of combining biomaterial surface engineering with photothermal therapy for applications in implant dentistry.

Effect of ascorbic acid on cellular respiration with mitochondrial reductase in gingival fibroblast.

Vitamin C or L-ascorbic acid has diverse functions in the body, especially healing promotion in tissue injury via participating in the hydroxylation reactions required for collagen formation. Systemic administration of vitamin C plays an important role on gingival fibroblast proliferation and functions. Whether local or rinsing administration of vitamin C alters gingival fibroblast wound healing behavior remains unclear. Therefore, it is of interest to investigate the effect of vitamin C on gingival fibroblast behavior utilizing cell culture. Primary human gingival fibroblasts isolated from gingival tissue were rinsed with medium containing various concentrations of vitamin C. Cell migration, cell viability was assessed using MTT assay. The viability assay showed >95% live cells, and no significant (P > 0.05) difference in these values was observed at different concentrations at 24 hrs. The levels of cell proliferation were not significantly different among the control and experimental groups in 24 hrs experimental time-points (p > 0.05). Vitamin C is nontoxic and can be used for further experiments to validate for clinical application. This was further confirmed with morphological examination after 24hrs incubation on control and experimental group drugs observed under the phase contrast microscope.

Novel Dextran Coated Cerium Doped Hydroxyapatite Thin Films.

Dextran coated cerium doped hydroxyapatite (Ca10-xCex(PO4)6(OH)2), with x = 0.05 (5CeHAp-D) and x = 0.1 (10CeHAp-D) were deposited on Si substrates by radio frequency magnetron sputtering technique for the first time. The morphology, composition, and structure of the resulting coatings were examined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), atomic force microscopy (AFM), metallographic microscopy (MM), Fourier transform infrared spectroscopy (FTIR), and glow discharge optical emission spectroscopy (GDOES), respectively. The obtained information on the surface morphologies, composition and structure was discussed. The surface morphologies of the CeHAp-D composite thin films are smooth with no granular structures. The constituent elements of the CeHAp-D target were identified. The results of the FTIR measurements highlighted the presence of peaks related to the presence of ν1, ν3, and ν4 vibration modes of (PO43−) groups from the hydroxyapatite (HAp) structure, together with those specific to the dextran structure. The biocompatibility assessment of 5CeHAp-D and 10CeHAp-D composite coatings was also discussed. The human cells maintained their specific elongated morphology after 24 h of incubation, which confirmed that the behavior of gingival fibroblasts and their proliferative capacity were not disturbed in the presence of 5CeHAp-D and 10CeHAp-D composite coatings. The 5CeHAp-D and 10CeHAp-D coatings’ surfaces were harmless to the human gingival fibroblasts, proving good biocompatibility.

Nanostructured Zirconia Surfaces Regulate Human Gingival Fibroblasts Behavior Through Differential Modulation of Macrophage Polarization.

Zirconia exhibits excellent biocompatibility and is widely used as dental implant materials in prosthodontics. Over the past years, research and development of dental implant biomaterials has focused on osseointegration, but few reports exist regarding the role of the immune environment on cellular responses to these materials. The present study investigates the effect of different nanostructured zirconia surface topographies on macrophage phenotypes and their influence on gingival fibroblast behavior. Three different nanostructured zirconia surfaces are characterized using scanning electron microscopy, atomic force microscopy, and water contact angle. Blank-machined zirconia (BMZ) surfaces were superior to RAW264.7 cell proliferation and adhesion. RAW264.7 seeded on all nanostructured zirconia surfaces polarized toward both inflammatory M1 and anti-inflammatory M2 macrophages with more M2 macrophage phenotype on BMZ surfaces. Meanwhile, conditioned media (CM) from RAW264.7 culture on three nanostructured zirconia surfaces inhibited cell apoptosis to human gingival fibroblasts (HGFs) but promoted HGF proliferation and secretion. Under modulation of RAW264.7 culture, HGFs cultured on BMZ surfaces significantly secreted more extracellular matrix with a higher expression of collagen-I (COL-I), vinculin (VCL), and fibronectin (FN) than those coated on self-glazed zirconia (CSGZ) and self-glazed zirconia (SGZ) surfaces. After being coated with a nano zirconia film, CSGZ surfaces showed certain changes in cell proliferation, adhesion, and protein production compared with SGZ surfaces. These findings will provide an overview of manipulating surface topography to modulate macrophage phenotypes in order to create an effective macrophage immune response and reinforce soft tissue integration.

Rinsing with L-Ascorbic Acid Exhibits Concentration-Dependent Effects on Human Gingival Fibroblast In Vitro Wound Healing Behavior.

Vitamin C or L-ascorbic acid has diverse functions in the body, especially healing promotion in tissue injury via participating in the hydroxylation reactions required for collagen formation. Systemic administration of vitamin C plays an important role on gingival fibroblast proliferation and functions. Whether local or rinsing administration of vitamin C alters gingival fibroblast wound healing behavior remains unclear. The aim of this study was to investigate the rinsing effect of vitamin C on gingival fibroblast behavior utilizing an in vitro wound healing model. Primary human gingival fibroblasts isolated from gingival tissue were rinsed with medium containing various concentrations of vitamin C. The rinsing effect of vitamin C on in vitro wound healing was assessed using a scratch test assay. Cell migration, cell viability, and extracellular matrix gene expression were analyzed by transwell migration assay, MTT assay, and real-time RT-PCR, respectively. We found that rinsing with 10 or 20 µg/ml vitamin C significantly increased fibroblast migration (p ≤ 0.05). However, no significant effect was found in the cell viability or in vitro wound healing assays. In contrast, rinsing with 50 µg/ml vitamin C significantly delayed wound closure (p ≤ 0.05). Real-time PCR demonstrated that 50 µg/ml vitamin C significantly increased fibroblast expression of COL1, FN, IL-6, and bFGF. The data demonstrate that rinsing with vitamin C (10/20 µg/ml) accelerates fibroblast migration. However, 50 µg/ml of vitamin C increases the expression of COL1, FN, IL-6, and bFGF, which are related to fibroblast wound healing activity. Prescribing vitamin C with the appropriate duration and drug administration method should be determined to maximize its benefit.

In vitro observation of macrophage polarization and gingival fibroblast behavior on three-dimensional xenogeneic collagen matrixes.

Collagen biomaterials are widely used for soft tissue augmentation. Cross-linking techniques for collagen matrix (CM) achieve mechanical and volumetric stability; nevertheless, cross-linking may compromise biocompatibility. The aim of the present study was to investigate two different three-dimensional (3D) porcine-derived CMs, noncross-linked (ncl)_CM and cross-linked (cl)_CM, for their effects on macrophages (Mφ) and gingival fibroblasts. The effects of the CMs on the cell viability, proliferation, and polarization of Mφ derived from human monocyte THP-1 cells were assessed. The effects of paracrine factors from Mφ cultured on the CMs were further studied in human gingival fibroblasts (HGF-1 cells). The spongy layer of ncl_CM was partially resorbed after 1 day of culture. cl_CM maintained increased numbers of viable cells when compared with ncl_CM on day 3 for both THP-1 and HGF-1 cells. Higher mRNA levels of M1 markers, including IL-1 and IL-6, were found in Mφ cultured on cl_CM, while no significant differences were observed in M2 marker expression levels, including Arg1 and CD206, for cells cultured on both CMs when compared with those of the control. Furthermore, the conditioned medium collected from Mφ cultured on both CMs decreased cell viability. Nevertheless, neither of the CM-conditioned media influenced the mRNA levels of TGF-β, COL1a2, and PDGF-A in HGF-1 cells when compared with the control media. A comparison showed that cl_CM tended to result in more viable cells than ncl_CM, while cl_CM polarized Mφ toward an M1 phenotype, which was confirmed by the observation of increased mRNA levels of pro-inflammatory cytokines.

Effects of different implant materials and surface microgrooves on the biological behavior of gingival fibroblasts

Objective: To study the effect of microgroove surface modification of titanium and zirconia on the biological behavior of gingival fibroblasts in order to find suitable surface materials for the transmucosal part of the dental implant. Methods: Twenty specimens were divided into four groups: smooth titanium (Ti-S), smooth zirconia (ZC-S), microgroove titanium (Ti-MG) and microgroove zirconia (ZC-MG) (five specimens in each group). Microgroove modification of titanium and zirconia surfaces was carried out by using fine machining chip system in the last two groups. The width of groove ridge was 60 μm, the width of groove was 60 μm, the depth of groove was 10 μm. The surface morphologies (the groove width and depth) were observed by scanning electron microscope (SEM), the surface roughness, static contact angle and elemental of specimens in each group were detected by SEM, atomic force microscope (AFM), optical contact angle measuring device and energy-dispersion X-ray analysis (EDX). Morphology of human gingival fibroblast (HGF) that arranged along the groove was analyzed using laser scanning confocal microscope by immunofluorescence staining. Differences in cell proliferation were analyzed and compared using cell counting kit. Expression level of intergrin α(5), β(1) and collagen Ⅰ mRNA were compared among different groups by quantitative real-time PCR for 6 h and 3 d. Results: The surface roughness of smooth titanium group and smooth zirconia group was (63.23± 2.55) and (26.78±3.11) nm, respectively. Microgroove zirconia group showed the best hydrophilicity: the static contact angle was 51.2°±2.0°. HGF was arranged along the groove surface, and cell proliferation results showed that proliferation on microgroove zirconia was more significant than that on other groups from 6 h to 7 d (P<0.05). Intergrin α(5) mRNA has the highest expression in microgroove zirconia (P<0.05) in the early adhesion (6 h), and there was no significant difference in the surface expression of intergrin β(1) and collagen Ⅰ mRNA in the early adhesion (6 h) of each group. However, in the late adhesion (3 d), intergrin α(5), β(1) and collagenⅠ mRNA expression in microgroove surface groups were higher than those of the smooth groups (P<0.05). Conclusions: Microgroove zirconia surface has small roughness and good hydrophilicity, which can guide HGF to line up in the groove, and this is beneficial to the HGF proliferation and the expression of structural proteins and functional proteins.

Implant abutment material and surface modifications effect on human gingival fibroblast behavior

Implant abutment material and surface modifications effect on human gingival fibroblast behavior

Macrophage behavior and interplay with gingival fibroblasts cultured on six commercially available titanium, zirconium, and titanium-zirconium dental implants.

The host-material interface has been a crucial relationship dictating the successful integration of biomaterials, including dental implants. The aim of the present study was to first investigate how macrophages behaved on various dental implant surfaces and thereafter to investigate their effect on soft tissue cells. Macrophage adhesion, proliferation, and polarization towards either an M1 or M2 phenotype were investigated on six implant surfaces fabricated from pure titanium (Ti), pure zirconium (ZLA), and a titanium-zirconium (Ti-Zi) alloy of various surface topographies/chemistries. Thereafter, conditioned media (CM) collected from macrophages seeded on these various implant surfaces was cultured with murine gingival fibroblasts and investigated for their ability to promote collagen synthesis. Macrophages attached and proliferated in similar levels on all implant surfaces; however, the modSLA hydrophilic surfaces tended to decrease the pro-inflammatory response by lowering the gene expression of TNF-alpha, IL-1, and IL-6 and promoting tissue resolution through the expression of an M2-macrophage cytokine IL-10. Thereafter, CM from macrophages were seeded with gingival fibroblasts on each implant surface. In general, CM from macrophages significantly promoted gingival fibroblast cell attachment on all implant surfaces at either 4 or 8h and, most notably, significantly promoted fibronectin and TGF-beta gene expression on both Ti and Ti-Zi hydrophilic surfaces. The present study found that implant surface topography and chemistry substantially impacted macrophage behavior. Most notably, modifications via hydrophilicity to both the pure Ti and Ti-Zi were shown to favor the secretion of macrophage pro-resolution markers and favored subsequent gingival fibroblast cell behavior when cultured with CM, whereas surface composition (Ti vs ZLA vs Ti-Zi) had little effect on macrophage polarization or gingival fibroblast behavior. This finding suggests that surface hydrophilicity would improve the soft tissue integration of dental implants, irrespective of material composition.

Dopamine self-polymerized along with hydroxyapatite onto the preactivated titanium percutaneous implants surface to promote human gingival fibroblast behavior and antimicrobial activity for biological sealing.

The clinical success of dental implants requires not only the optimum osseointegration but also the integration of implant surface with soft tissues to form biological sealing. In this study, alkali-heat treatment was applied to modify the pure titanium surface constructing a unique micro-and nano-structure. Then, poly(dopamine), along and with the additional incorporation of hydroxyapatite and carboxymethyl chitosan have been successfully infiltrated into the preactivated Ti surface during dopamine self-polymerization proceeding. Here, the effects of poly(dopamine)-modified surface coating on the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens have been systematically studied, which was critical for the early peri-implant soft tissue integration. The results showed that the poly(dopamine)-modified alkali-heat-titanium surface was a superior substrate for human gingival fibroblast adhesion, spread and proliferation. Moreover, further enhancements on cytoskeleton organization, collagen secretion and fibronectin adsorption were generally observed through the additional incorporation of hydroxyapatite. The addition of carboxymethyl chitosan exerted a positive modulation effect on antibacterial activity. Overall, our study demonstrated that combined superior soft tissue integration and antibacterial activity can be achieved by using poly(dopamine)-modified titanium implant, which has great potential in the optimal design of dental implant.

The role of macrophage polarization on fibroblast behavior-an in vitro investigation on titanium surfaces.

This study investigated the effect of smooth and rough titanium surface topographies on macrophage polarization and their influence on gingival fibroblast behavior cultured on titanium surfaces. RAW 264.7 macrophages were seeded on smooth (pickled titanium (PT)) and rough Sand-blasted with Large grit particles followed by Acid-etching (SLA) titanium surfaces and first investigated for macrophage polarization towards tissue-inflammatory M1 macrophages or wound-healing M2 macrophages. Thereafter, culture media collected from macrophages on both surfaces were cultured with gingival fibroblasts seeded on their respective topographies. All experiments were performed in triplicate with three independent experiments. Macrophages seeded on SLA surfaces polarized towards tissue-inflammatory M1 macrophages at early time points. Immunofluorescent staining and RT-PCR analysis demonstrated higher levels of iNOS and gene expression of IL-1β, IL-6, and TNF-alpha on SLA surfaces at 3days when compared to both tissue culture plastic (TCP) and PT surfaces (p<0.001). Very little differences were found between smooth PT surfaces and TCP. Interestingly, proliferation assay (CCK-8) suggested that conditioned media (CM) from macrophages seeded on SLA surfaces drastically inhibited gingival fibroblast proliferation at 3 and 5days (p<0.001). Meanwhile, CM from macrophages cultured on SLA surfaces also significantly reduced collagen 1 synthesis on SLA surfaces at 14days as assessed by immunofluorescent staining (p<0.001). The results from this study demonstrate that the polarization of macrophages towards a pro-inflammatory (M1) phenotype on SLA surfaces may have a negative impact on gingival fibroblast behavior on titanium surfaces. Future strategies to better modulate macrophage polarization should be investigated to support a favorable immune response and encourage tissue integration. As SLA surfaces have a potential to shift macrophages towards tissue-inflammatory M1 macrophages, this might be a negative impact for soft tissue healing. Therefore, SLA surfaces should be kept within the bone, as when in contact with soft tissue, they are prone to support a lack of soft tissue integration leading to inflammation.

Behavior of Gingival Fibroblasts on Titanium Implant Surfaces in Combination with either Injectable-PRF or PRP.

Various strategies have been employed to speed tissue regeneration using bioactive molecules. Interestingly, platelet concentrates derived from a patient’s own blood have been utilized as a regenerative strategy in recent years. In the present study, a novel liquid platelet formulation prepared without the use of anti-coagulants (injectable-platelet-rich fibrin, i-PRF) was compared to standard platelet-rich plasma (PRP) with gingival fibroblasts cultured on smooth and roughened titanium implant surfaces. Standard PRP and i-PRF (centrifuged at 700 rpm (60× g) for 3 min) were compared by assays for fibroblast biocompatibility, migration, adhesion, proliferation, as well as expression of platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), collagen1 (COL1) and fibronectin (FN). The results demonstrate that i-PRF induced significantly higher cell migration, as well as higher messenger RNA (mRNA) levels of PDGF, TGF-β, collagen1 and fibronectin when compared to PRP. Furthermore, collagen1 synthesis was highest in the i-PRF group. These findings demonstrate that liquid platelet concentrates can be formulated without the use of anticoagulants and present much translational potential for future research. Future animal and clinical trials are now necessary to further investigate the potential of utilizing i-PRF for soft tissue regenerative protocols in combination with various biomaterials.

α-tocopherol decreases interleukin-1β and -6 and increases human β-defensin-1 and -2 secretion in human gingival fibroblasts stimulated with Porphyromonas gingivalis lipopolysaccharide.

Periodontitis, a disease associated with chronic inflammation, results in significant destruction of periodontal tissues. Uncontrolled, periodontal disease negatively affects general patient health. We sought to evaluate the effect of α-tocopherol on gingival fibroblast behavior following exposure to Porphyromonas gingivalis lipopolysaccharide (LPS). Primary human gingival fibroblasts were cultured for 24 and 48h with α-tocopherol at various concentrations (0, 50, 100 and 200μm) in the presence or absence of 1μg/mL of LPS. At the end of each time point, cell adhesion and growth were evaluated by means of optical microscope observations and MTT assay. The secretion levels of cytokines interleukin (IL)-1β and IL-6 and human β-defensins 1 and 2 were measured by specific enzyme-linked immunosorbent assay. Finally, an invitro scratch wound assay was performed to investigate the effect of α-tocopherol on fibroblast migration. α-tocopherol alone had no adverse effect on cell adhesion and morphology. Fibroblast proliferation increased in the presence of α-tocopherol with and without LPS. α-tocopherol alone had no effect on inflammatory cytokine (IL-1β and IL-6) secretion. Interestingly, following cell exposure to P.gingivalis LPS, α-tocopherol significantly (p<0.01) decreased the secretion of these two cytokines and increased human β-defensin-1 and -2 secretion. Finally, α-tocopherol increased the healing rate of the gingival fibroblasts from 12h up to 48h. These results suggest that α-tocopherol may play an active role in countering the damaging effect of LPS by reducing inflammatory cytokines, increasing β-defensins and promoting fibroblast growth, migration and wound healing.

Modulation of human dermal microvascular endothelial cell and human gingival fibroblast behavior by micropatterned silica coating surfaces for zirconia dental implant applications

Dental ceramic implants have shown superior esthetic behavior and the absence of induced allergic disorders when compared to titanium implants. Zirconia may become a potential candidate to be used as an alternative to titanium dental implants if surface modifications are introduced. In this work, bioactive micropatterned silica coatings were produced on zirconia substrates, using a combined methodology of sol–gel processing and soft lithography. The aim of the work was to compare the in vitro behavior of human gingival fibroblasts (HGFs) and human dermal microvascular endothelial cells (HDMECs) on three types of silica-coated zirconia surfaces: flat and micropatterned (with pillars and with parallel grooves). Our results showed that cells had a higher metabolic activity (HGF, HDMEC) and increased gene expression levels of fibroblast-specific protein-1 (FSP-1) and collagen type I (COL I) on surfaces with pillars. Nevertheless, parallel grooved surfaces were able to guide cell growth. Even capillary tube-like networks of HDMEC were oriented according to the surface geometry. Zirconia and silica with different topographies have shown to be blood compatible and silica coating reduced bacteria adhesion. All together, the results indicated that microstructured bioactive coating seems to be an efficient strategy to improve soft tissue integration on zirconia implants, protecting implants from peri-implant inflammation and improving long-term implant stabilization. This new approach of micropatterned silica coating on zirconia substrates can generate promising novel dental implants, with surfaces that provide physical cues to guide cells and enhance their behavior.

The effect of laser‐treated titanium surface on human gingival fibroblast behavior

Surface modification, as a means of enhancing soft tissue integration in titanium would have significant advantages including less marginal bone resorption, predictable esthetic outcome, improved soft tissue stability, and seal against bacterial leakage. The aim of this study was to evaluate the effects of laser-roughened titanium surfaces on human gingival fibroblast (HGF) viability, proliferation, and adhesion. Titanium discs were ablated with impulse laser in four different patterns. Polished and sand-blasted titanium discs were used as control groups. Specimen surface properties were determined using optical profilometry and scanning electron microscopy. HGF behavior on modified surfaces was analyzed using cell adhesion, viability, proliferation, and ELISA assays. Results suggested that modified Ti surfaces did not affect the viability of HGFs and improved adhesion was measured in laser treatment groups after 24 h. However, proliferation study showed that the adsorbance of fibroblast cells after 72 h cultured on polished titanium was higher and comparable with that of control cells. As for focal adhesion kinase (FAK), cells grown on laser modified surfaces had higher expression of FAK as compared with polished titanium. In conclusion, tested laser-treated surfaces seem to favor HGF adhesion. There were no significant differences between different laser treatment groups.

Effects of Whole Cigarette Smoke on Human Gingival Fibroblast Adhesion, Growth, and Migration

The aim of this study was to investigate the effects of a single exposure to whole cigarette smoke on human gingival fibroblast behavior. Normal oral mucosa fibroblasts were exposed once to whole cigarette smoke for 5, 15, or 30 min, and then were used to analyze cell adhesion, β1-integrin expression, cell growth and viability, cell capacity to contract collagen gel, and cell migration following wound infliction. Our findings showed that when gingival fibroblasts were exposed once to whole cigarette smoke, this resulted in a significant inhibition of cell adhesion, a decrease in the number of β1-integrin-positive cells, increased LDH activity in the target cells, and reduced growth. The smoke-exposed fibroblasts were also not able to contract collagen gel matrix and migrate following insult. Overall results demonstrate that a single exposure to whole cigarette smoke produced significant morphological and functional deregulation in gingival fibroblasts. This may explain the higher predisposition of tobacco users to oral infections and diseases such as cancer.

Effect of radiation on cytokines, MMP-1 and type I collagen mRNA expressions in human gingival fibroblasts.

e16034 Background: Oral mucositis is an acute injury to the mucosal lining of the head and neck region associated with radiation therapy (RT). In this study, we aimed to elucidate the effects of radiation on the proliferation of gingival fibroblasts and proinflammatory cytokines and matrix metalloproteinase-1 (MMP-1), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and type I collagen (COL I) mRNA expressions of gingival fibroblasts. Methods: Gingival fibroblasts were isolated from human gingival connective tissue of systemically healthy individuals. These cells were treated with radiation dosages as follows; control group (untreated), 0.5 Gry, 1 Gry, 2 Gry, 4 Gry, 6 Gry, and 8 Gry. RT was applied in the form of a single dose which was applied with linac 6 MV photon beams. Cell proliferation was determined by counting cells at 24 and 48 hrs. Total RNA was isolated at 24 hours after radiation. Expression of interleukin (IL)-1 beta, IL-6, IL-8 and MMP-1, TIMP-1 transcripts in HGFs was determined by quantitative PCR (QPCR) analysis. Morphology of gingival fibroblasts was evaluated using inverted microscope after different dosages of radiation. For proliferation experiments and gene expressions, the statistical analysis used was one-way analysis of variance (ANOVA) and Turkey HSD multiple comparison tests. Results: Radiation decreased cell proliferation (p<0.05) compared to the control group. Expression of IL1beta, IL-6 and IL-8 was stimulated at higher dosage (8 Gry) of radiation (p<0.001) (figure 1). In parallel, MMP-1, and TIMP-1 mRNA expressions were elevated in response to highest dosage of radiation (p<0.001) (figure 2). Radiation suppressed COL I mRNA expression in response to all dosages at 24 hrs (p<0.001). Conclusions: These findings demonstrated that radiation even in a single dose regulates behavior of gingival fibroblasts. Radiation-induced inflammatory characteristics of gingival fibroblasts could potentially lead to a disruption of oral mucosa. Results of this study clarify the possible mechanisms of radiation induced oral mucositis in radiation treated cancer patients.

Effects of different setting of diode laser on the mRNA expression of growth factors and type I collagen of human gingival fibroblasts

The aim of this study was to analyze the influence of non-surgical applications of diode laser (940 nm) on the cell proliferation and mRNA expressions of type I collagen and growth factors in human gingival fibroblasts (GF). Gingival fibroblasts were isolated from human gingival connective tissue of systemically healthy individuals. Cells were treated with different laser parameters as follows; (1) Infected pocket setting (power: 2 W, pulse interval: 1 ms, pulse length: 1 ms, 20 s/cm(2)); (2) Perio-pocket setting (power: 1.5 W, pulse interval: 20 ms, pulse length: 20 ms, 20 s/cm(2)); and (3) Biostimulation setting (power: 0.3 W in continuous wave, 20 s/cm(2)). Proliferation of GF was evaluated after different laser applications using a real-time cell analyzer. Total RNA was isolated on day 2 and cDNA synthesis was performed. Type I collagen, insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β) mRNA expressions were determined with quantitative RT-PCR. In a proliferation experiment, no significant differences were observed in the different laser applications when compared to the control group. Statistically significant increases in IGF, VEGF, and TGF-β mRNA expressions were noted in the laser groups when compared to the untreated control group (p < 0.05). A significant increase in collagen type I mRNA expression was noted in only biostimulation set-up of diode laser (p < 0.05). The results of this study demonstrate that non-surgical laser applications modulate behavior of gingival fibroblasts inducing growth factors mRNA expressions and these applications can be used to improve periodontal wound healing.

Effects of LP-MOCVD prepared TiO 2 thin films on the in vitro behavior of gingival fibroblasts

We report on the in vitro response of human gingival fibroblasts (HGF-1 cell line) to various thin films of titanium dioxide (TiO 2) deposited on titanium (Ti) substrates by low pressure metal-organic chemical vapor deposition (LP-MOCVD). The aim was to study the influence of film structural parameters on the cell behavior comparatively with a native-oxide covered titanium specimen, this objective being topical and interesting for materials applications in implantology. HGF-1 cells were cultured on three LP-MOCVD prepared thin films of TiO 2 differentiated by their thickness, roughness, transversal morphology, allotropic composition and wettability, and on a native-oxide covered Ti substrate. Besides traditional tests of cell viability and morphology, the biocompatibility of these materials was evaluated by fibronectin immunostaining, assessment of cell proliferation status and the zymographic evaluation of gelatinolytic activities specific to matrix metalloproteinases secreted by cells grown in contact with studied specimens. The analyzed surfaces proved to influence fibronectin fibril assembly, cell proliferation and capacity to degrade extracellular matrix without considerably affecting cell viability and morphology. The MOCVD of TiO 2 proved effective in positively modifying titanium surface for medical applications. Surface properties playing a crucial role for cell behavior were the wettability and, secondarily, the roughness, HGF-1 cells preferring a moderately rough and wettable TiO 2 coating.

Cell surface glycoconjugates of gingival fibroblasts exposed to dental plaque extract.

The cell surface glycoconjugates of human gingival fibroblasts exposed in a culture to dental plaque extract were studied by surface labeling techniques and indirect immunoflurescennce. After 24 h of exposure, the fibroblast morphology changed from well‐spread to spindle‐like. This alteration was associated with a disappearance of the intercellular fibronectin (FN) network and most of the high molecular weight cell surface glycoproteins. These effects of the extract were prevented by heating. After prolonged treatment with the native extract, a 80 kd glycoprotein disappeared and a 140 kd glycoprotein was replaced by a 110 kd polypeptide, but the trypsin sensitive 55 kd glycoprotein remained on the surface of the treated cells. The protcolytic activity of the plaque extract degraded the FN to various fragments with a different molecular weight than previously obtained with several purified mammalian enzymes. After a 24 h incubation of the treated cells in a normal, serum supplemented medium, the normal surface characteristics and FN network were recovered. In the treated cells, the phosphorylation of the cell surface glycoproteins was increased as well as the activity of the hyaluronic acid synthetase. The results suggest that plaque extract has a dual role in affecting the behavior of gingival fibroblasts. First, the enzymatic degradation of the FN network and surface glycoproteins destroys the association between the extracellular matrix and the cytoskeleton. Second, heat‐stable components alter the cell surface phosphorylation. These changes are associated with an activation of the cells to produce hyaluronic acid, the most striking anabolic change obtained in treated cells.