Photobiomodulation using LLLT and LED of cells involved in osseointegration and peri-implant soft tissue healing.

This study evaluated the influence of photobiomodulation (PBM) using low-level laser therapy (PBM/LLLT) or light-emitting diode (PBM/LED) therapy on peri-implant tissue healing. A laboratory model was used to assess the adhesion and metabolism of osteoblasts (SaOs-2), human gingival fibroblasts (HGF), and normal oral keratinocytes (NOK) seeded on a titanium (Ti) surface. After seeding the cells on disks of Ti placed in wells of 24-well plates, three irradiations were performed every 24 h at energy density of 3 J/cm2. For PBM/LLLT, a LaserTABLE device was used with a wavelength of 780 nm and 25 mW, while for PBM/LED irradiation, a LEDTABLE device was used at 810 nm, 20 mW, at a density of 3 J/cm2. After irradiations, the number of cells (NC) attached and spread on the Ti surface, cell viability (CV), total protein (TP), and collagen (Col) synthesis were assessed. Alkaline phosphate activity (ALP) was evaluated only for SaOs-2. Data were submitted to ANOVA complemented by Turkey statistical tests at a 5% significance level. PBM significantly increased adherence of NOK to the Ti surface, while no significant effect was observed for SaOs-2 and HGF. PBM positively affected CV, as well as Col and TP synthesis, in distinct patterns according to the cell line. Increased ALP activity was observed only in those cells exposed to PBM/LLLT. Considering cell specificity, this investigation reports that photobiomodulation with low-power laser and LED at determined parameters enhances cellular functions related to peri-implant tissue healing in a laboratory model.

Effects of EGF-coated titanium surfaces on adhesion and metabolism of bisphosphonate-treated human keratinocytes and gingival fibroblasts.

OBJECTIVE: To assess the effects of epidermal growth factor (EGF)-coated titanium (Ti) discs on the adhesion and metabolism of keratinocytes and gingival fibroblasts exposed to nitrogen-containing bisphosphonates. MATERIALS AND METHODS: Keratinocytes and fibroblasts were seeded (1 × 105 cells/disc) on Ti discs coated with EGF (100 nM). After 24 h, cells were exposed or not to sodium alendronate (SA) or zoledronic acid (ZA) at different concentrations (0 = control, 0.5, 1, or 5 µM) for 48 h. Cell adhesion to the substrates was evaluated by fluorescence microscopy. Cell viability (alamarBlue, n = 6) and synthesis of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), and keratinocytes growth factor (KGF) (ELISA, n = 6) were assessed. Data were statistically analyzed by one-way ANOVA and Tukey tests (α = 0.05). RESULTS: Higher cell adhesion rate was observed when keratinocytes and fibroblasts were seeded onto EGF-coated discs in comparison to uncoated discs. ZA treatment hindered the adhesion of both cell lines on the Ti discs as well as reduced the viability and synthesis of VEGF, KGF and MMP-2 by cells (p < 0.05). SA treatment did not affect cell viability, but interfered negatively on the adhesion and synthesis of EGF and KGF by the cells (p < 0.05). EGF-coated surface increased cell viability and synthesis of growth factors as well as downregulated the synthesis of MMP-2 in comparison to control (p < 0.05). CONCLUSION: EGF applied on Ti surface improves the biological responses of oral mucosa cells exposed to SA and ZA. CLINICAL RELEVANCE: EGF-coating on titanium may be a suitable strategy to improve oral mucosa cellular events related to biological sealing, especially for patients under bisphosphonate therapy.

Influence of bisphosphonates on oral implantology: Sodium alendronate and zoledronic acid enhance the synthesis and activity of matrix metalloproteinases by gingival fibroblasts seeded on titanium.

OBJECTIVE: This study aimed to assess the influence of the bisphosphonates zoledronic acid and sodium alendronate on MMP-2 and MMP-9 synthesis and activity by gingival fibroblasts seeded onto titanium substrate. DESIGN: Titanium discs were placed in 24-well cell culture plates and gingival fibroblasts were seeded (1 × 105 cells/discs) on them using Dulbecco's Modified Eagle's Medium (DMEM) + 10 % fetal bovine serum (FBS) for 24 h. After this period, a fresh serum-free DMEM containing zoledronic acid or sodium alendronate at 0.5 µM, 1 µM or 5 µM was applied on the cells for an additional of 24 h. Serum-free DMEM and tumor necrosis factor alpha (TNF-α) were used as negative and positive controls, respectively. MMP-2 and MMP-9 synthesis and activity were determined by ELISA (Enzyme-Linked Immunosorbent Assay) and conventional/in situ zymography. Quantitative data were analyzed by one-way ANOVA and Tukey's tests (α = 0.05). The in situ zymography data were qualitatively described. RESULTS: Despite both bisphosphonates increased the MMPs synthesis, this effect was significant higher in zoledronic acid groups. MMPs activity resembled by gelatinolytic activity was also enhanced by sodium alendronate and zoledronic acid in a similar pattern. CONCLUSIONS: Zoledronic acid and sodium alendronate increased in a dose-dependent manner MMP-2 and MMP-9 synthesis by gingival fibroblasts seeded on titanium. MMP-2 activity was up-regulated by zoledronic acid treatment.