Effect of different concentrations of commercially available mouthwashes on wound healing following periodontal surgery: a randomized controlled clinical trial.

OBJECTIVES: The purpose of this study was to evaluate the effect of chlorhexidine and essential oils containing mouth rinses on oral wound healing after periodontal flap surgery. MATERIALS AND METHODS: Eighty subjects participated in the study and were randomly assigned to use water, 0.12% chlorhexidine (CHX), essential oils (EO), 5% CHX, and 10% EO. Subjects were examined at 1, 2, and 3 weeks postoperatively. Plaque index (PI) and the modified gingival index (GI) were recorded, while wound epithelialization was measured to evaluate the healing process. Numerical data were analyzed with parametric test for multiple comparisons (ANOVA) with Bonferroni correction. Categorical data were analyzed using Chi-square test/fisher exact test. RESULTS: All groups demonstrated a gradual GI reduction from first to third visit. Patients in the CHX group presented statistically significant lower PI scores than patients in the water group at the all-time points of the study. Wound epithelialization analysis demonstrated that 100% of the sites in the CHX group were healing by secondary intention at visit 1. This finding was statistically significant. CONCLUSION: Full strength concentrations of CHX and EO did not show any detrimental effects on healing after traditional periodontal surgery at the end of the observation period. CLINICAL RELEVANCE: The use of chlorhexidine and EO containing mouthwashes does not appear to delay wound healing. Diluting these commercial mouthwashes may present an approach that could possibly reduce the adverse effects (such as tooth staining) associated with their use, while maintaining their antibacterial properties.

Cytotoxic effects of silver diamine fluoride.

PURPOSE: To investigate the effect of silver diamine fluoride (SDF) and fluoride varnish (FV) on human gingival fibroblasts (HGF) and bacteria. METHODS: HGF cell viability was assessed after exposure to various dilutions of SDF or FV. Hydroxyapatite (HA) discs treated with SDF, FV, or saline were rinsed in artificial saliva for 84 days. HGF were exposed to treated discs and viability assessed fluorescently. Oral bacteria were exposed to treated discs and survival quantified. RESULTS: At 0.01%, SDF was almost 100% cytotoxic to HGF. SDF and FV treated HA discs, induced near-complete cell death after 24 hours of contact. After rinsing FV discs for 21 days, cell survival exceeded 95%. SDF treated discs were toxic to HGF and bacteria after 9 weeks of rinsing. CLINICAL SIGNIFICANCE: SDF and FV can induce cell death. FV lost its cytotoxicity within 3 weeks, while SDF remained cytotoxic even after 9 weeks of rinsing. This research confirms that SDF has long lasting antimicrobial effects at very low concentrations although it does raise concerns regarding cytotoxicity. However, HGF cells are exposed to other cytotoxic substances in dentistry with little, if any, long-term effects.

Synthesis, antibacterial activity, and biocompatibility of new antibacterial dental monomers.

PURPOSE: To synthesize a small library of antibacterial dental monomers based on quaternary ammonium salts and to test their antibacterial activity against cariogenic bacteria. METHODS: Five new antibacterial monomers were synthesized and characterized by NMR, IR and HRMS. RESULTS: Cytotoxicity assays using human gingival fibroblast cells showed that these new antibacterial monomers were biocompatible at concentrations of 10⁻5 M and displayed less cytotoxicity than BisGMA, a common dental monomer. When analyzed in vitro, all new monomers demonstrated strong inhibitory activity against biofilm formation by cariogenic Streptococcus mutans and Lactobacillus casei. Results indicated that antibacterial monomers containing a long alkyl (i.e. hexadecyl) chain are superior to their shorter-chain counterparts. The cross-linking monomers based on glycerol dimethacrylate also consistently outperformed their monomethacrylate analogs. Finally, the ammonium salts containing the dimethylbenzyl moiety were superior to the similar structures containing 1,4-diazabicyclo[2.2.2]octane (DABCO) in some cases. CLINICAL SIGNIFICANCE: All five new monomers were deemed biocompatible at concentrations of 10⁻5 M or less, and most had better biocompatibility than BisGMA. Dimethacrylate monomers 5 and 6 generally demonstrated high antibacterial activities, with the highest activity shown for the most lipophilic monomer 6, and these new antibacterial monomers have potential future application in dental composites and bonding agents.

Effectiveness of Vanish XT in Reducing the Development of White Spot Lesions: An In Vitro Study.

PURPOSE: To evaluate the effectiveness of Vanish XT in preventing white spot lesions (WSLs) when placed around orthodontic brackets. The efficacy of Vanish XT was compared with that of Pro Seal, a commercially available product already proven in preventing demineralization. MATERIALS AND METHODS: Sixty extracted human canine teeth were divided into three groups (n = 20). The two experimental groups were treated with either Vanish XT or Pro Seal. A third group received no treatment (control). Ethidium bromide with DNA was added to and mixed with the products to produce fluorescence to verify retention of the experimental products. The teeth were submersed in a lactic acid solution for 32 days to create WSLs. All sample teeth were brushed twice daily with a non-fluoride toothpaste to evaluate retention of the experimental products. Photos were taken under fluorescence microscopy and white light at three time intervals. Demineralization was quantified utilizing computer software, and photos were analyzed to obtain values for percent surface area of demineralization and surface color change. RESULTS: Percent surface area of WSL data, both under white light conditions and fluorometric analysis, revealed a significant difference between Pro Seal and Vanish XT when compared with the control group. No significant differences were found between Pro Seal and Vanish XT treated teeth. Fluorescence evaluation revealed that both experimental products were largely removed by 32 days of brushing and acid exposure. CONCLUSION: Vanish XT is effective in preventing demineralization around orthodontic brackets. Its preventive efficacy is equivalent to that of Pro Seal.

Synthesis, Antifungal Activity, and Biocompatibility of Novel 1,4-Diazabicyclo[2.2.2]Octane (DABCO) Compounds and DABCO-Containing Denture Base Resins.

The fungal pathogen Candida albicans causes a variety of oral infections, including denture stomatitis, which is characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. While antifungal treatment reduces symptoms, infections are often recurrent. One strategy to address this problem is to incorporate compounds with fungicidal activities into denture materials to prevent colonization. Our laboratory synthesized novel derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO), which is an organic compound typically used as a catalyst in polymerization reactions. DABCO derivatives with different aliphatic chain lengths (DC16, DC16F, DC18, and C6DC16), as well as methacrylate monomers conjugated to DABCO compounds (DC11MAF and C2DC11MAF), were synthesized and tested for antimicrobial activity. All the compounds exhibited fungicidal activity against several Candida species at concentrations ranging between 2 and 4 µg/ml. Moreover, acrylic denture base resins fabricated to contain 1, 2, or 4 wt% DABCO compounds inhibited surface C. albicans biofilm formation, as well as fungal growth, in disc diffusion assays. Remarkably, discs (4 wt%) aged for 2 months also exhibited approximately 100% growth-inhibitory activity. While some DABCO compounds exerted intermediate to high cytotoxicity against mammalian oral cell types, DC11MAF and denture base resin discs containing 2 or 4 wt% C2DC11MAF exhibited relatively low cytotoxicity against periodontal ligament (PDL) cell and gingival fibroblast (GF) lines, as well as primary oral epithelial cells. These studies demonstrate that DABCO derivatives can be incorporated into denture materials and exert fungicidal activity with minimal cytotoxicity to mammalian cells. DC11MAF and C2DC11MAF are considered strong candidates as therapeutic or preventive alternatives against Candida-associated denture stomatitis.

In vitro comparison of zinc-based, chlorhexidine, and essential oil mouth rinses.

BACKGROUND: Chlorhexidine (CHX)-based mouth rinses are frequently prescribed following periodontal surgeries. A more recently available brand of zinc-based mouth rinses advertises one of its mouth rinses as a substitute for chlorhexidine. The purpose of this study was to evaluate, in vitro, the effects of this brand of zinc-based mouth rinses on cell survival, cell motility, and gene expression of human gingival fibroblasts (HGFs). METHODS: HGFs were exposed to essential oil (EO), CHX, and three types of one brand of zinc-based mouth rinses designed to treat breath malodor (ZnA), dry mouth (ZnB), and gingivitis (ZnC). Each mouth rinse was tested over a range of concentrations for its effects on HGF survival and motility. Gene expression of cytokines, interleukins, and growth factors were evaluated via reverse transcriptase-polymerase chain reaction (RT-PCR), as a means to assess potential influences on inflammation and wound healing. RESULTS: Cell survival was significantly decreased for CHX and ZnC at 10% dilutions (p < 0.05). For all time points, cells exposed to ZnC displayed the greatest reduction in cell motility (p < 0.05). The various mouth rinses examined differentially altered the expression of growth factor transcripts. ZnC particularly enhanced the expression of BMP-2 and FGF-2. CONCLUSION: ZnC was more cytotoxic and inhibited cell motility to a greater extent than any of the other mouth rinses. Therefore, using ZnC as an alternative to CHX could potentially have negative effects on wound healing after periodontal surgery. However, further investigation is required to confirm the clinical relevance of these in vitro findings. PLAIN LANGUAGE SUMMARY: One type of zinc-based mouth rinse designed to replace chlorhexidine (often prescribed after oral surgeries) demonstrated the greatest oral cell death and reduction in cell movement when compared to other zinc-based mouth rinses. These zinc-based mouth rinses also reduced the amounts of proteins involved in regulating inflammation, potentially reducing the destruction of bone holding the teeth in place. They also changed the amounts of several molecules involved in tissue healing. It is unknown if this will speed or slow the healing of the soft tissues of the mouth.

Utilization of a periodontal endoscope in nonsurgical periodontal therapy: A randomized, split-mouth clinical trial.

BACKGROUND: The removal of subgingival calculus to obtain gingival health is an integral part of nonsurgical periodontal therapy. The periodontal endoscope is used by some clinicians to help enhance access to effectively remove subgingival calculus; however, longer-term studies on this subject are still lacking. The purpose of this randomized, controlled clinical trial was to compare the clinical outcomes of scaling and root planing (SRP) using a periodontal endoscope versus conventional SRP using loupes for up to 12 months, utilizing a split-mouth design. METHODS: Twenty-five patients were recruited who exhibited generalized stage II or stage III periodontitis. SRP was rendered by the same experienced hygienist using either a periodontal endoscope or conventional SRP using loupes, following random assignment of the left and right halves of the mouth. All periodontal evaluations were done by the same periodontal resident at baseline, and at 1, 3, 6, and 12 months after therapy. RESULTS: Single-rooted teeth interproximal sites displayed a significantly lower percentage of improved sites (P < 0.05) than multirooted teeth for probing depth and clinical attachment level (CAL). Maxillary multirooted interproximal sites favored the use of the periodontal endoscope at the 3- and 6-month time periods (P = 0.017 and 0.019, respectively) in terms of the percentage of sites with improved CAL. Mandibular multirooted interproximal sites showed more sites with improved CAL using conventional SRP than with the periodontal endoscope (P < 0.05). CONCLUSION: Overall, the use of a periodontal endoscope was more beneficial in multirooted sites compared to single-rooted sites, specifically in maxillary multirooted sites.

The Effects of Irrigants on the Survival of Human Stem Cells of the Apical Papilla, Including Endocyn.

INTRODUCTION: Endocyn, a pH-neutral solution of hypochlorous acid and hypochlorite has been developed for use as an endodontic irrigant. The purpose of this study was to evaluate the effect of Endocyn on human periodontal ligament (PDL) fibroblasts, rat osteosarcoma cells (UMR-106), and stem cells of the apical papilla (SCAP) compared with other commonly used endodontic irrigants. METHODS: To determine cytotoxicity, cells were exposed to various concentrations of Endocyn, 6% sodium hypochlorite (NaOCl), 17% EDTA, and 2% chlorhexidine for 10 minutes, 1 hour, or 24 hours. Cell survival was measured fluorescently using calcein AM. Endocyn also was tested for its ability to inhibit SCAP proliferation and alkaline phosphatase activity. Finally, SCAP transcript expression was examined via reverse-transcriptase polymerase chain reaction. RESULTS: Endocyn was no more toxic to PDL and UMR cells than water for up to 24 hours. Endocyn concentrations of 50% were toxic to SCAP after 1 hour of exposure. Endocyn concentrations of >20% inhibited SCAP proliferation, whereas concentrations of ≥10% inhibited alkaline phosphatase activity. Exposure of SCAP to 10% Endocyn for 3 days did not alter most transcript expression, but did significantly reduce the expression of alkaline phosphatase, fibromodulin, and osteomodulin. CONCLUSION: Endocyn was significantly less cytotoxic to PDL, UMR-106, and SCAP cells compared with other commonly used endodontic irrigants. High concentrations of Endocyn did inhibit some transcript expression and alkaline phosphatase activity, indicating a potential reduction in the osteogenic potential of stems cells exposed to Endocyn.

Greater Sensitivity of Oral Fibroblasts to Smoked Versus Smokeless Tobacco.

BACKGROUND: Smokers have an increased incidence and severity of periodontal disease. Although cigarette smoke contains >4,000 chemical components that could affect periodontal tissues, less is understood about the effect of smokeless tobacco. Therefore, this study compares the effects of cigarette smoke extract (CSE) and smokeless tobacco extract (STE) on cell survival and motility of periodontal ligament (PDL) and gingival fibroblasts in vitro. METHODS: PDL and gingival fibroblasts were exposed to various concentrations of CSE, STE, or nicotine alone. Viable cells were labeled with calcein acetoxymethyl, visualized using fluorescent microscopy, and quantified using a fluorescence multi-well plate reader. In vitro wounding and collagen gel contraction assays were used to assess cell motility. RESULTS: Both gingival and PDL fibroblasts displayed reduced cell viability with increasing concentrations of CSE and STE. Based on relative nicotine content, CSE was significantly more cytotoxic than STE. PDL fibroblasts were also more sensitive to both CSE and STE compared with gingival fibroblasts. Finally, sublethal doses of CSE reduced cell motility and gel contraction, whereas STE had less effect. Nicotine alone ≤0.5 mM had little to no effect in any of these assays. CONCLUSIONS: Many of the underlying effects of tobacco products on periodontal tissues may be due to direct inhibition of normal fibroblast function. CSE is found to be more deleterious to the function of both PDL and gingival fibroblasts than STE. PDL fibroblasts appear to be more sensitive to CSE and STE than gingival fibroblasts. Therefore, cigarette smoke may have more profound effects than smokeless tobacco.

Photo-cross-linked Antibacterial Zein Nanofibers Fabricated by Reactive Electrospinning and its Effects against Streptococcus mutans.

Native zein electrospun nanofibers have shown poor solvent resistance and low mechanical strength. Compared to other toxic cross-linkers, a safer method of stabilizing zein based fibers while retaining or with improved mechanical strength is needed to convert these materials for biomedical applications where culture media or body fluids may be present. We report here a method of fabricating non-toxic zein nanofibers using reactive electrospinning coupled with in situ photo-cross-linking. The cross-linked zein nanofibers exhibited significantly improved mechanical strength and sustained morphology against water and aqueous ethanol solution. This process doesn't require additional conventional cross-linking agents to form cross-linking network, which is advantageous for biomedical applications. Antimicrobial monomer with photo-reactive moiety was coupled with methacrylate zein nanofibers and showed strong inhibitory activity against cariogenic Streptococcus mutans. Cytotoxicity test with human gingival fibroblasts revealed high biocompatibility.

Transcript profiling of periodontal fibroblasts and osteoblasts.

BACKGROUND: Fibroblasts are critical to the establishment and maintenance of the periodontal attachment apparatus (cementum, periodontal ligament [PDL], and bone). In order to characterize the cellular changes that accompany periodontal regeneration, better tools are necessary to distinguish periodontal ligament fibroblasts (PDLF), gingival fibroblasts, and osteoblasts. Our goal is to identify gene markers to better characterize and identify these cell types. METHODS: We chose to examine and compare the expression of numerous gene transcripts by semiquantitative reverse transcriptase-polymerase chain reaction using primers specific for 44 different gene transcripts in order to better characterize the identity of these cells. RESULTS: Several transcripts were cell-type specific. Specifically, fibromodulin was expressed only in PDL fibroblasts, while osteopontin was expressed only in dermal fibroblasts. In addition, lumican was expressed by all three types of fibroblasts (PDL, gingival, and dermal), while alkaline phosphatase was expressed by osteoblasts as well as PDL and gingival fibroblasts. CONCLUSIONS: Our results indicate that PDL fibroblasts are distinct from either gingival or dermal fibroblasts or osteoblasts. In general, PDL and gingival fibroblasts displayed greater similarity to each other than either displayed toward dermal fibroblasts. Furthermore, both gingival and PDL fibroblasts displayed greater similarity to osteoblasts than to dermal fibroblasts, possibly reflecting their common origin (the neural crest).

Effect of locally delivered doxycycline hyclate on human fibroblast attachment to subgingival calculus.

BACKGROUND: Clinical studies using locally applied doxycycline hyclate (DHV) have demonstrated significant probing depth reduction and gain in clinical attachment as a monotherapy without scaling and root planing. The mechanism for this attachment level gain to the non-root planed tooth is not understood. The purpose of this study was to investigate the effect of locally applied doxycycline hyclate on human gingival fibroblast attachment to subgingival calculus on contaminated root surfaces. METHODS: Two separate experiments were performed, both on subgingival calculus. In experiment 1, teeth with subgingival calculus were treated with either doxcycycline hyclate in bioabsorbable vehicle (DHV) or with vehicle control (VC) in vivo. In experiment 2, teeth with subgingival calculus were treated with DHV, VC, scaling and root planing (SRP), or no treatment in vitro. The amount of cell attachment to calculus-covered root surfaces was quantitatively compared using a fluorescent dye assay and epifluorescence microscope. Values for cell attachment are presented as the mean standard deviation of the mean. The data were evaluated using Student t test. RESULTS: In both experiments, there was no statistically significant difference in fibroblast attachment in the DHV, VC, or no treatment groups (P >0.05). The SRP group showed significantly more cellular attachment to tooth surfaces formerly covered by subgingival calculus than all other groups (P <0.001). In general, more cells attached to cementum than to calculus. Root chips that showed no attachment to the subgingival calculus also had no cells attached to the adjacent cemental root surface. CONCLUSION: The addition of doxycycline hyclate in a bioabsorbable vehicle used as a locally delivered drug did not enhance the initial cellular attachment of human gingival fibroblasts to subgingival calculus or contaminated root surfaces.

Resistance to cigarette smoke is increased in periodontal ligament cells by attachment to collagen and fibronectin.

BACKGROUND: The toxic effects of cigarette smoke often presents in smokers as increased incidence and severity of periodontal disease. These patients demonstrate symptomatic inflammation, increased probing depth, and tooth loss likely attributable to the direct effects of cigarette smoke on periodontal ligament (PDL) fibroblasts. The goal of this in vitro study is to investigate the direct effects of smoking on PDL fibroblasts, focusing on cell-extracellular matrix (ECM) interactions and cell survival. METHODS: PDL cells were plated for various times on tissue culture plastic, PDL-derived ECMs, collagen Type I, or fibronectin. Cells were exposed to various concentrations of cigarette smoke extract (CSE) at different times during the cell attachment process. Subsequently, cell survival was quantified using calcein-acetoxymethyl ester compound and a fluorescent plate reader. RESULTS: After exposure to CSE, PDL cell survival increased with increased cell attachment time to plastic. These observations were independent of soluble factors present in PDL cell-conditioned media. PDL-derived ECMs and collagen Type I-pretreated plates promoted increased cell survival after 1 day of cell attachment. Fibronectin-pretreated plates demonstrated increased cell survival after 3 days of cell attachment. CONCLUSIONS: Cell-ECM interactions increase survival of PDL cells exposed to CSE. It is suggested that the increased survival is attributable to PDL cells altering their ECM, potentially by depositing collagen and fibronectin. This may imply that cells embedded in an ECM would be more resistant to the toxic effects of cigarette smoke, leading to increased cell death near the exposed edges of a wound.

The putative collagen-binding peptide P-15 promotes fibroblast attachment to root shavings but not hydroxyapatite.

BACKGROUND: Regenerative periodontal treatment aims to restore the attachment of the periodontal ligament and gingival collagen fibers to both the cementum of the root surface and alveolar bone. Fibroblasts are the predominant cells of the periodontal ligament and gingiva and have important roles in the function and regeneration of the tooth-supporting apparatus. This study investigated whether a putative collagen-based cell-binding peptide (P-15) increases gingival fibroblast attachment to root shavings and bone replacement graft (BRG) materials. METHODS: Gingival and dermal fibroblast attachment to root shavings and BRG materials, and cell proliferation on root shavings and sections were measured fluorometrically. Root shavings and root sections obtained from periodontally healthy teeth were treated with P-15 at 2 concentrations (200 ng/g or 400 ng/g). Citric acid (CA)-treated root materials were also compared to untreated root shavings and root sections that served as negative control groups. RESULTS: Attachment of all cells to bone fragments (whether freeze-dried or demineralized) was significantly greater than to hydroxyapatite (HA)-based BRG materials. The addition of P-15 to HA did not significantly increase gingival or dermal fibroblast attachment. At a concentration of 400 ng/g, P-15 significantly increased gingival and dermal fibroblast attachment to root shavings as compared to untreated shavings. Bone fragments, HA-based BRG materials, and untreated root shavings inhibited gingival fibroblast proliferation. Treatment of root sections with P-15 did not have any effect on gingival fibroblast proliferation. CONCLUSIONS: P-15 is a potential alternative to CA for promoting fibroblast attachment to root surfaces. However, P-15 did not enhance fibroblast proliferation on root sections.

Adhesion of human fibroblasts to root-end-filling materials.

This study evaluated the attachment of cultured explants of human periodontal ligament fibroblasts and gingival fibroblasts to different root-end-filling materials. Although periodontal ligament and gingival fibroblasts initially attached avidly to Geristore, these same cells displayed no significant attachment to ProRoot, Tytin amalgam, or SuperEBA. With further incubation on Geristore, the attachment of both periodontal ligament and gingival fibroblasts improved and these cells proliferated. In contrast, no improvement in attachment or proliferation was observed for cells incubated for greater times with ProRoot, Tytin amalgam, or SuperEBA. Because the attachment characteristics of these two groups of fibroblasts were identical, we examined the potential role of the extracellular matrix family of receptors (integrins) on the attachment of gingival fibroblasts. Gingival fibroblast attachment to collagen type I was determined to be dependent on alpha1beta1 and alpha2beta1 integrins, whereas their attachment to the RGD-binding sequence of fibronectin and vitronectin was partially inhibited by antibodies to the beta1 and alphaV integrin subunits. However, attachment of gingival fibroblasts to Geristore was not reduced by the addition of any of the attachment-perturbing anti-integrin antibodies examined. Thus, gingival fibroblasts attach to Geristore, but this attachment was mediated by mechanisms other than integrins.

Introducing evidence-based dentistry to dental students using histology.

The expansion of evidence-based dentistry (EBD) is essential to the continued growth and development of the dental profession. Expanding EBD requires increased emphasis on critical thinking skills during dental education, as noted in the American Dental Education Association's Competencies for the New General Dentist. In order to achieve this goal, educational exercises must be introduced to increase the use of critical thinking skills early in the dental curriculum, with continued reinforcement as students progress through subsequent years. Described in this article is one approach to increasing student exposure to critical thinking during the early basic science curriculum-specifically, within the confines of a traditional histology course. A method of utilizing the medical and dental research literature to reinforce and enliven the concepts taught in histology is described, along with an approach for using peer-to-peer presentations to demonstrate the tools needed to critically evaluate research studies and their presentation in published articles. This approach, which could be applied to any basic science course, will result in a stronger foundation on which students can build their EBD and critical thinking skills.

A novel GuttaFlow sealer supports cell survival and attachment.

INTRODUCTION: The purpose of this in vitro study was to compare the biocompatibility of a novel formulation of a silicone-based endodontic sealer GuttaFlow 2 (GF2; Coltène/Whaledent, Langenau, Germany) with the original (GFO) and fast-set (GFF) formulations of GuttaFlow and with an epoxy resin sealer, AHPlus Jet (AH+J; Dentsply, York, PA). METHODS: Sealers were set into 3 × 5.5 mm discs. Cell culture media was used to extract leachable products at 24 hours and 1, 2, and 4 weeks. Primary human periodontal ligament fibroblasts were incubated with sealer elutes for 24 hours and evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and the calcein AM assay. Cell attachment was evaluated on set sealer that was either rinsed or unrinsed with cell media for 1 week. Statistical analysis was performed using the Student t test. RESULTS: Both calcein and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays revealed that periodontal ligament cell viability was reduced on AH+J at 1, 2, and 4 weeks compared with all GuttaFlow sealers. There were no differences in cell viability between the GuttaFlow samples, and all displayed high rates of cell survival at all time periods. After 2 hours, cell attachment to the rinsed GFO and GFF samples exceeded the control, and at 24 hours cell attachment on all GuttaFlow samples exceeded the control. AH+J sealers supported significantly less cell attachment when compared with all GuttaFlow sealers. Cell attachment to set sealers showed better cell attachment when rinsed compared with unrinsed. CONCLUSIONS: GuttaFlow sealers were more biocompatible than AHJ in vitro. The novel GF2 displayed comparable biocompatibility with GFF and GFO.

Pedialyte promotes periodontal ligament cell survival and motility.

INTRODUCTION: The search still continues to find the best storage media for avulsed teeth. Unfortunately, some of the recommended storage solutions are not commonly found in households or do not preserve the periodontal ligament (PDL) cells long-term. The purpose of the present study was to determine whether Pedialyte is a viable alternative storage solution for avulsed teeth by assessing its ability to preserve human PDL cell viability. METHODS: Human PDL cells were exposed to 6 different storage solutions (minimal essential medium [MEMα], Hank's balanced salt solution [HBSS], non-fat milk, coconut water, Pedialyte, or tap water) for 2, 6, 24, or 48 hours at 4°C or 25°C. Cell viability was quantified immediately or 1 week after exposure. The effects of these storage solutions on PDL cell motility and bacterial proliferation were also examined. The results were statistically analyzed by analysis of variance. RESULTS: Pedialyte at 4°C and 25°C showed significantly (P < .001) higher cell survival compared with water after all time intervals. No significant difference was noted between control (MEMα), HBSS, coconut water, and Pedialyte at 4°C after 2 hours. Cells stored in Pedialyte for 24 hours at 25°C and assayed 1 week later showed significantly higher cell survivability compared with milk. Pedialyte supported significantly less bacterial growth compared with non-fat milk and coconut water. No difference in cell motility was observed for cells stored for 24 hours in Pedialyte, MEMα, HBSS, milk, or coconut water. CONCLUSIONS: Pedialyte is a viable alternative as a storage solution for avulsed teeth.

Electrochemical dissolution of nickel-titanium endodontic files induces periodontal ligament cell death.

INTRODUCTION: Fractured endodontic files present a major problem. A novel method has been proposed to retrieve fractured nickel-titanium (NiTi) endodontic files by using electrochemical dissolution. However, the effect of file dissolution on adjacent soft tissues such as the periodontal ligament (PDL) has not been investigated. The aim of this study was to determine the effects of the dissolution products on PDL fibroblasts. METHODS: Endodontic files were dissolved in sodium fluoride (NaF) by passing a 50-mA current through the NiTi files while immersed in the NaF solution. NaF/NiTi solutions were diluted with minimal essential medium-α media containing 10% serum. PDL cells were treated for up to 24 hours, and cell viability was quantified by using calcein AM to label live cells and ethidium homodimer to label dead cells. This was repeated by using artificial saliva (AS) as an alternative to NaF. RESULTS: NaF solution reduced PDL cell survival, and the NaF/NiTi solution further reduced PDL cell survival. AS alone did not reduce cell survival, whereas AS/NiTi solution reduced PDL cell survival. Particles that resulted from the electrochemical dissolution of NiTi files were highly cytotoxic. CONCLUSIONS: Electrochemically dissolving NiTi files in NaF results in solutions that are cytotoxic to PDL fibroblasts. AS may be a less toxic alternative for dissolving NiTi files.

Effect of essential oil and chlorhexidine mouthwashes on gingival fibroblast survival and migration.

BACKGROUND: Chemical plaque control is the most commonly recommended means of oral hygiene after periodontal surgery. Commercially available mouthwashes contain a variety of active ingredients that have bactericidal properties but may potentially be toxic to the host cells. The goal of this in vitro study is to investigate the effect of commercially available mouthwashes on the survival and migratory capacity of human fibroblasts. METHODS: Human gingival and periodontal ligament (PDL) fibroblasts were treated with commercially available mouthwashes that contained either chlorhexidine (CHX) or essential oils (EO) as the active ingredient. Each mouthwash was tested over a range of concentrations for its ability to affect fibroblast survival and migration, as well as long-term effects on cell viability. RESULTS: Undiluted mouthwashes induced near-complete cell death 24 hours after only a 60-second treatment. Dilutions of 15% to 20% for both CHX and EO mouthwashes resulted in 50% cell death. When diluted to 10% to 15%, EO did not reduce cell migration, whereas similar dilutions of CHX resulted in reduced cell migration. Concentrations of 10% of both EO and CHX mouthwashes retained most of their antibacterial capacity. Treatment with EO did not result in gingival fibroblast death, whereas 5% CHX resulted in near-complete gingival fibroblast death 7 days after exposure. CONCLUSIONS: The results of this in vitro study indicate that diluted EO displayed no detectable detrimental effects on human gingival and PDL fibroblasts, whereas diluted CHX reduced both cell migration and long-term survival. Both solutions retained their antimicrobial activity in lower concentrations.