The Effects of Three Chlorhexidine-Based Mouthwashes on Human Osteoblast-Like SaOS-2 Cells. An In Vitro Study

Effect of clindamycin on human osteoblasts treated with zoledronate: An in vitro study

OBJECTIVE

The objective of this study was to determine the effects of combined treatment with clindamycin and zoledronate on the growth and differentiation of cultured human osteoblasts.

DESIGN

Human osteoblasts, obtained by primary culture from mandibular bone fragments, were cultured in the presence of 50 μM zoledronate, 150 μg/mL clindamycin, or the combination of both (zoledronate + clindamycin). The effect on cell proliferation was evaluated at 24 h by the MTT colorimetric method, using a spectrophotometer at 570 nm. The effect on differentiation was examined by measuring alkaline phosphatase (ALP) activity, and mineralization by the osteoblast was studied by staining with alizarin red. Real-time polymerase chain reaction (RT-PCR) was performed for gene expression analysis. Data were expressed as means±standard deviation, and analysis of variance was performed, applying Bonferroni correction when interactions were significant.

RESULTS

Treatment of osteoblasts with 50 μM zoledronate significantly reduced cell proliferation and differentiation and the gene expression of certain markers versus controls (p < 0.001). However, treatment with 150 μg/mL clindamycin significantly increased cell proliferation and differentiation and the gene expression of certain markers (p < 0.05). The combination of 150 μg/mL clindamycin and 50 μM zoledronate partially counteracted the loss of osteoblast proliferative and differentiation capacity caused by zoledronate.

CONCLUSION

Treatment with low-dose clindamycin can reverse the negative impact of zoledronate on osteoblast proliferation and differentiation. Follow-up animal studies and clinical trials are needed before topical clindamycin can be considered as a possible therapeutic resource for BP-treated patients who require a GBR procedure.

Antimicrobial Effect and Cytocompatibility After Using Different Decontamination Methods on Titanium Implant Surfaces: An In Vitro Study

AIM

To evaluate in vitro the antibacterial efficacy and cytocompatibility of different implant-decontamination methods, using both 2D and 3D peri-implant mucosa models.

METHODS

Four decontamination methods [chlorhexidine (CHX), electrolytic treatment (GS), curcumin (CUR), xanthohumol (XN)] were compared in four independent experiments, three with a 2D peri-implant mucosa model on titanium surfaces and another on a 3D peri-implant mucosa model. These decontamination procedures were tested for their antibacterial effect using a multispecies biofilm model with Streptococcus oralis , Actinomyces naeslundii , Veillonella dispar , and Porphyromonas gingivalis for 24 h. Direct cytocompatibility evaluating the impact of the treatments on tissue cells as well as indirect cytocompatibility (colonization of treated implant surfaces by tissue cells) were also tested. Both outcomes were assessed by confocal laser scanning microscopy supported by neural networks.

RESULTS

CHX demonstrated a strong alteration of cytocompatibility and antibacterial effect, but did not remove biofilm biomass. XN and CUR demonstrated antibacterial effect and biofilm removal action, as well as cytocompatibility. GS showed antibacterial capacity with a combination of areas completely clean of biofilm with others in which a non-vital biofilm remained. In the 3D peri-implant mucosa model, XN and CUR showed maintenance of the mucosa integrity after treatment, whereas CHX and GS displayed disruption in the mucosal layers.

CONCLUSIONS

Phytotherapeutics (CUR and XN) were the most cytocompatible substances and showed the largest antimicrobial effect. GS displayed antibiofilm activity with a localized "bubble-shaped effect" and impaired tissue cell morphology and integrity, compromising cytocompatibility, and CHX showed antimicrobial capacity, without reducing biofilm biomass and with altered cytocompatibility.

Development of a Multilayer Film Including the Soluble Eggshell Membrane Fraction for the Treatment of Oral Mucosa Lesions

BACKGROUND/OBJECTIVES

Oral diseases causing mucosal lesions are normally treated with local or systemic anti-inflammatory, analgesic and antimicrobial agents. The development of topical formulations, including wound-healing promoters, might speed up the recovery process, improving patients' quality of life, and reduce the risk of deterioration in health conditions. In this study, a mucoadhesive multilayer film, including a novel biocompatible substance (solubilized eggshell membrane, SESM), was rationally designed.

METHODS

The SESM preparation procedure was optimized and its biological effects on cell proliferation and inflammation marker gene expression were evaluated in vitro; preformulation studies were conducted to identify the most promising polymers with film-forming properties; then, trilayer films, consisting of an outer layer including chlorhexidine digluconate as a model drug, a supporting layer and a mucoadhesive layer, incorporating SESM, were prepared using the casting method and their mechanical, adhesion and drug release control properties were evaluated.

RESULTS

SESM proved to possess a notable wound-healing capacity, inducing a wound closure of 84% in 24 h without inhibiting blood clotting. The films revealed a maximum detachment force from porcine mucosa of approx. 1.7 kPa and maximum in vivo residence time of approx. 200-240 min; finally, they released up to 98% of the loaded drug within 4 h.

CONCLUSIONS

The formulated trilayer films were found to possess adequate properties, making them potentially suitable for protecting oral lesions and favoring their rapid healing, while releasing antimicrobial substances that might be beneficial in reducing the risk of bacterial infections.

Topical Oxygen Therapy for Promoting Healing After Implant Placement Using Blue® M Gel: A Report of Two Cases

Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, are distinguished by a gradual onset of inflammation within the peri-implant mucosa, resulting in bone resorption and, ultimately, implant failure. Topical oxygen therapy is recognized for its ability to decrease inflammation, enhance blood flow, and provide a bacteriostatic effect. Utilizing oxygen-based therapy products as a local treatment for peri-implant mucositis and peri-implantitis may lead to comparable clinical results as traditional local adjuncts such as chlorhexidine, antibiotics, and antibacterial agents. This article discusses two case reports in which the Blue® M gel was utilized. In the first case, a 50-year-old female patient with a decade-long history of betel quid chewing and missing upper right first and second molars was treated with Blue® M gel to reduce the chances of peri-implantitis and promote healing following a first-stage surgical procedure for implant placement. In the second case, Blue® M gel was applied to a 56-year-old female patient who experienced pain and inflammation one week after the initial surgical procedure for implant placement to restore the missing posterior teeth on the lower right side. The use of the Blue® M gel led to accelerated healing in both instances.

Effect of amoxicillin and clindamycin on the gene expression of markers involved in osteoblast physiology

Background/purpose

Amoxicillin and clindamycin are the most effective decontaminants for intraoral bone grafts before their application in bone regeneration without cytotoxic effects on osteoblasts, but their effects on the gene expression of markers involved in osteoblast growth and differentiation remain unclear. The study objective was to determine the effects of amoxicillin and clindamycin on the gene expression of markers involved in osteoblast growth and differentiation.

Materials and methods

Real-time polymerase chain reaction (RT-PCR) was performed to explore the effect of 150 μg/mL clindamycin or 400 μg/mL amoxicillin on the gene expression by primary human osteoblasts (HOBs) of runt-related transcription factor 2 (Runx-2), osterix (OSX), alkaline phosphatase (ALP), osteocalcin (OSC), osteoprotegerin (OPG), receptor activator for nuclear factor κ B ligand (RANKL), type I collagen (Col-I), bone morphogenetic proteins 2 and 7 (BMP-2 and BMP-7), TGF-β1 and TGF-β receptors (TGF-βR1, TGF-βR2, and TGF-βR3), and vascular endothelial growth factor (VEGF).

Results

Treatment with 150 μg/mL clindamycin significantly increased the gene expression of TFG-β1, TGF-βR1, TGF-βR2, TGF-βR3, RUNX-2, Col-1, OSX, OSC, BMP-2, BMP-7, ALP, VEGF, and RANKL by HOBs. Treatment with 400 μg/mL amoxicillin significantly increased the gene expression of TGF-β R1, Col-I, OSC, RANKL, and OPG alone.

Conclusion

These findings suggest that 150 μg/mL clindamycin is the decontaminant of choice to treat intraoral bone grafts before their application in bone regeneration. The osteogenic and antibacterial properties of clindamycin can favor and accelerate the integration of bone grafts in the oral cavity.

Effectiveness of mechanical and chemical decontamination methods for the treatment of dental implant surfaces affected by peri-implantitis: A systematic review and meta-analysis

OBJECTIVE

To assess which decontamination method(s) used for the debridement of titanium surfaces (disks and dental implants) contaminated with bacterial, most efficiently eliminate bacterial biofilms.

MATERIAL AND METHODS

A systematic search was conducted in four electronic databases between January 1, 2010 and October 31, 2022. The search strategy followed the PICOS format and included only in vitro studies completed on either dental implant or titanium disk samples. The assessed outcome variable consisted of the most effective method(s)-chemical or mechanical- removing bacterial biofilm from titanium surfaces. A meta-analysis was conducted, and data was summarized through single- and multi-level random effects model (p < .05).

RESULTS

The initial search resulted in 5260 articles after the removal of duplicates. After assessment by title, abstract, and full-text review, a total of 13 articles met the inclusion criteria for this review. Different decontamination methods were assessed, including both mechanical and chemical, with the most common method across studies being chlorhexidine (CHX). Significant heterogeneity was noted across the included studies. The meta-analyses only identified a significant difference in biofilm reduction when CHX treatment was compared against PBS. The remaining comparisons did not identify significant differences between the various decontamination methods.

CONCLUSIONS

The present results do not demonstrate that one method of decontamination is superior in eliminating bacterial biofilm from titanium disk and implant surfaces.

Effect of antibacterial photodynamic therapy with chitosan nanoparticles on Aggregatibacter actinomycetemcomitans

BACKGROUND

This study aimed to assess the effect of antibacterial photodynamic therapy (aPDT) with chitosan nanoparticles on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in the culture medium.

MATERIALS AND METHODS

In this in vitro, experimental study, chitosan nanoparticles (CHNPs) containing indocyanine green (ICG) were first synthesized and characterized. A. actinomycetemcomitans was cultured on trypticase soy agar. The culture media containing A. actinomycetemcomitans were randomly subjected to the following six decontamination protocols: negative control subjected to sterile phosphate buffered saline (PBS) for 5 min, positive control exposed to 0.2 % chlorhexidine (CHX) for 5 min, exposure to 0.25 mg/mL ICG in the dark at 37 °C for 5 min, aPDT with 0.25 mg/mL ICG and diode laser (808 nm, 250 mW, 14.94 J/cm2, 30 s, 1 mm distance, 8 mm tip diameter), exposure to CHNPs containing 0.25 mg/mL ICG in the dark at 37 °C for 5 min, and aPDT with CHNPs containing 0.25 mg/mL ICG and diode laser. The number of colonies was counted, and analyzed by one-way ANOVA and Tamhane test (alpha=0.050).

RESULTS

Antimicrobial PDT with CHNPs, and CHX groups comparably showed the highest decontamination efficacy (P = 0.000).

CONCLUSION

The results showed optimal efficacy of aPDT with CHNPs containing 0.25 mg/mL ICG and 808 nm diode laser for reduction of A. actinomycetemcomitans colony count. Thus, aPDT appears to be as effective as CHX, but with fewer adverse effects.

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used.

Chlorhexidine-loaded poly (amido amine) dendrimer and a dental adhesive containing amorphous calcium phosphate nanofillers for enhancing bonding durability

OBJECTIVE

A novel method of combining chlorhexidine (CHX) loaded poly (amido amine) (PAMAM) dendrimers with a dental adhesive containing amorphous calcium phosphate (ACP) nanofillers are proposed for etch-and-rinse bonding system to enhance resin-dentin bonding durability.

METHODS

The CHX-loaded PAMAM and ACP nanofillers were synthesized and characterized. Their effects on the cytotoxicity were tested by MTT assay. Micro-tensile bond strength (μTBS) before and after thermomechanical challenges were used to evaluate the bonding durability. Anti-matrix metalloproteinase (MMPs) property was examined using in-situ zymography. A double-fluorescence technique was used to examine interfacial permeability after bonding. Dentin remineralization in Ca/P lacking solution was observed under scanning electron microscopy.

RESULTS

Compared with a 0.2 wt% CHX solution, the PAMAM loaded CHX had less cytotoxicity, while the in situ zymography showed it could still inhibit MMPs activity within the hybrid layer after released from PAMAM. The application of the novel method maintained the μTBS better than the control group after thermomechanical challenges, and it did not negatively affect water permeability of the bonding interfaces. CHX-loaded PAMAM regulated the calcium (Ca) and phosphate (P) ions provided by the ACP-containing adhesives to remineralize the demineralized dentin surfaces without initial Ca/P in the environment.

SIGNIFICANCE

The novel method can reduce the cytotoxicity of CHX, inhibit MMPs activities, maintain μTBS, and induce dentin remineralization, which are crucial factors for enhancing bonding durability.

Effect of Three Chlorhexidine-Based Mouthwashes on Human Gingival Fibroblasts: An In Vitro Study

Mouthwashes containing chlorhexidine (CHX) are deemed to be associated with dose-dependent side effects, including burning sensation and taste alteration. To overcome these drawbacks, mouthwashes with CHX at lower concentrations with or without adjunctive agents are proposed. The aim of this in vitro study was to investigate the effects of three CHX-based mouthwashes on human gingival fibroblasts (HGFs). After 3 days of cell culture, groups were randomly treated for 30 s, 60 s or 120 s with (a) CHX 0.05% in combination with cetylpyridnium chloride (CPC) 0.05%; (b) CHX 0.1%; (c) CHX 0.2%; or (d) NaCl as control. Cell viability, cytotoxicity and apoptosis were evaluated at 2 h, 3 days and 6 days after the exposure to the different solutions. Similar cell viability values were found among the test groups at all time points. At day 0, higher cytotoxicity was measured in the group treated with CHX 0.02%, in particular after long application time (120 s), while no significant difference was found between CHX + CPC and the control group. All the investigated mouthwashes were well tolerated by HGF cells for the tested application times. The highest cytotoxic effect was observed for CHX 0.2%; therefore, clinicians should consider limiting its usage to carefully selected clinical situations.