Disparity in the Influence of Implant Provisional Materials on Human Gingival Fibroblasts with Different Phases of Cell Settlement: An In Vitro Study.

The development of healthy peri-implant soft tissues is critical to achieving the esthetic and biological success of implant restorations throughout all stages of healing and tissue maturation, starting with provisionalization. The purpose of this study was to investigate the effects of eight different implant provisional materials on human gingival fibroblasts at various stages of cell settlement by examining initial cell attachment, growth, and function. Eight different specimens-bis-acrylic 1 and 2, flowable and bulk-fill composites, self-curing acrylic 1 and 2, milled acrylic, and titanium (Ti) alloy as a control-were fabricated in rectangular plates (n = 3). The condition of human gingival fibroblasts was divided into two groups: those in direct contact with test materials (contact experiment) and those in close proximity to test materials (proximity experiment). The proximity experiment was further divided into three phases: pre-settlement, early settlement, and late settlement. A cell culture insert containing each test plate was placed into a well where the cells were pre-cultured. The number of attached cells, cell proliferation, resistance to detachment, and collagen production were evaluated. In the contact experiment, bis-acrylics and composites showed detrimental effects on cells. The number of cells attached to milled acrylic and self-curing acrylic was relatively high, being approximately 70% and 20-30%, respectively, of that on Ti alloy. There was a significant difference between self-curing acrylic 1 and 2, even with the same curing modality. The cell retention ability also varied considerably among the materials. Although the detrimental effects were mitigated in the proximity experiment compared to the contact experiment, adverse effects on cell growth and collagen production remained significant during all phases of cell settlement for bis-acrylics and flowable composite. Specifically, the early settlement phase was not sufficient to significantly mitigate the material cytotoxicity. The flowable composite was consistently more cytotoxic than the bulk-fill composite. The harmful effects of the provisional materials on gingival fibroblasts vary considerably depending on the curing modality and compositions. Pre-settlement of cells mitigated the harmful effects, implying the susceptibility to material toxicity varies depending on the progress of wound healing and tissue condition. However, cell pre-settlement was not sufficient to fully restore the fibroblastic function to the normal level. Particularly, the adverse effects of bis-acrylics and flowable composite remained significant. Milled and self-curing acrylic exhibited excellent and acceptable biocompatibility, respectively, compared to other materials.

Enhanced functionality and migration of human gingival fibroblasts on vacuum ultraviolet light-treated titanium: An implication for mitigating cellular stress to improve peri-implant cellular reaction.

PURPOSE: The maintenance of peri-implant health relies significantly on the integrity of the peri-implant seal, particularly vulnerable at the interface between implant abutment and soft tissue. Early healing stages around implants involve cellular exposure to oxidative stress. This study aimed to investigate whether vacuum ultraviolet (VUV)-treated titanium augments the growth and functionality of human gingival fibroblasts while mitigating cellular stress. METHODS: Machined titanium plates underwent treatment with 172 nm VUV light for one minute, with untreated plates as controls. Human gingival fibroblasts were cultured on treated and untreated plates, and their behavior, growth, and functionality were assessed. Functionally impaired fibroblasts, treated with hydrogen peroxide, were also cultured on these titanium plates, and plate-to-plate transmigration ability was evaluated. RESULTS: Fibroblasts on VUV-treated titanium exhibited a 50% reduction in intracellular reactive oxygen species production compared to controls. Additionally, glutathione, an antioxidant, remained undepleted in cells on VUV-treated titanium. Furthermore, the expression levels of inflammatory cytokines IL-1ß and IL-8 decreased by 40-60% on VUV-treated titanium. Consequently, fibroblast attachment and proliferation doubled on VUV-treated titanium compared to those in the controls, leading to enhanced cell retention. Plate-to-plate transmigration assays demonstrated that fibroblasts migrated twice as far on VUV-treated surfaces compared to those in the controls. In particular, the transmigration ability, impaired in functionally impaired fibroblasts on the controls, was preserved on VUV-treated titanium. CONCLUSIONS: VUV-treated titanium promotes the growth, function, and migration of human gingival fibroblasts by reducing cellular stress and enhancing antioxidative capacity. Notably, the transmigration ability significantly improved on VUV-treated titanium.

Human Gingival Fibroblast Growth and Function in Response to Laser-Induced Meso- and Microscale Hybrid Topography on Dental Implant Healing Abutments.

PURPOSE: To examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. MATERIALS AND METHODS: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by a variety of tests, including cell density assay (WST-1), fluorescence microscopy, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and detachment tests. RESULTS: The machined surface showed monodirectional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of monodirectional mesoscale channels (15-µm pitch) and woven oblique microridges formed within the channels. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, or collagen production between the machined and laser-textured surfaces. Fibroblasts growing on a laser-textured surface were found to spread in one direction along the mesochannels, while cells growing on machined surfaces tended to spread randomly. Fibroblasts on laser-textured surfaces were 1.8 times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and transmembrane adhesion linker gene (integrin ß-1) were upregulated on laser-textured surfaces. CONCLUSIONS: The increased fibroblast retention, uniform growth, and increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created and hybrid-textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface; in addition, they support its extended use, from implants and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable.