Effect of short-time povidone-iodine application on osteoblast proliferation and differentiation

Effects of antiseptic irrigation solutions on osseointegration in a cementless tibial implantation mouse model

Despite the success of standard antiseptic irrigation solutions in reducing periprosthetic joint infection (PJI) rates, there is still a need for more effective solutions. Synergistic use of povidone-iodine (PI) and hydrogen peroxide (H2O2) has shown promising results; however, the optimal solution concentration balancing bactericidal activity and osseointegration remains unknown. This study aims to evaluate the impact of these antiseptic irrigation solutions on osseointegration and the bone-implant interface strength in vivo. Forty C57BL/6 mice underwent bilateral tibial implantation surgery and were randomly allocated into three groups receiving 0.3% PI, 10% PI mixed with 3% H2O2, or saline as irrigation solutions intraoperatively. Assessments were performed on postoperative Days 1 and 28, including plain radiographs, microcomputed tomography (microCT) evaluation, histological analysis, immunohistochemistry, and biomechanical pull-out testing. No wound complications were observed. MicroCT scans revealed no differences in peri-implant trabecular bone parameters. Biomechanical pull-out testing showed no differences in the bone-implant interface strength across groups. Histological analysis indicated no differences in bone and bone marrow percentage areas among treatment groups. Immunohistochemical analysis demonstrated no differences among groups in peri-implant osteocalcin, osterix, or endomucin-positive cells. In conclusion, using either antiseptic irrigation solution showed no differences in osseointegration parameters compared to the control group, demonstrating safety and the absence of toxicity. CLINICAL RELEVANCE: Dilute 0.3% povidone-iodine and a 1:1 combination of 10% povidone-iodine mixed with 3% hydrogen peroxide can be safely used during primary and revision total joint arthroplasty without compromising osseointegration or causing wound complications.

Clinical Efficacy of Different Concentrations of Povidone Iodine in the Management of Peri-Implant Mucositis

Mechanical plaque control is the first line of management of peri-implant diseases. Povidone iodine is one of the broad spectrum and potent antiseptics available at various concentrations. The aim of the study was to assess and compare the efficacy of various concentrations of povidone iodine in the management of peri-implant mucositis. In the present double blinded, parallel designed, randomized clinical trial, a total of 60 patients with peri-implant mucositis (20 participants in each group [Group 1 (povidone iodine 0.1%), Group 2 (povidone iodine 2%) and Group 3 (povidone iodine 010%)] were enrolled. Scaling and root planing was done and then the peri-implant sulcus was irrigated with respective irrigant and repeated once in a week for 4 weeks. Loe and Silness Gingival Index (GI) and Mombelli Modified sulcular bleeding index (BI) were recorded at baseline and after a month and compared. Statistical analysis was done using One-way ANOVA and Tukey's HSD post hoc test. A statistically significant difference (P = 0.000) observed between the three concentrations when compared after 1 month. Also, a statistically significant difference between Group 1 and Group 3 and Group 2 and Group 3 was observed in terms of post GI (P = 0.000) and post BI (P = 0.000) but statistically no significant difference was observed between Group 1 and Group 2 in terms of post GI (P = 0.171) and post BI (P = 0.338). The 2% and 10% povidone iodine showed significant improvement in gingival index and bleeding index and hence it could be an effective adjunct to scaling and root planing in the management of peri-implant mucositis.

Potential side effects of antibacterial coatings in orthopaedic implants: A systematic review of clinical studies

Objective: The systematic review aimed to determine the potential side effects of antibacterial coatings in orthopaedic implants. Methods: Publications were searched in the databases of Embase, PubMed, Web of Science and Cochrane Library using predetermined keywords up to 31 October 2022. Clinical studies reporting side effects of the surface or coating materials were included. Results: A total of 23 studies (20 cohort studies and three case reports) reporting the concerns about the side effects of antibacterial coatings were identified. Three types of coating materials, silver, iodine and gentamicin were included. All of studies raised the concerns regarding safety of antibacterial coatings, and the occurrence of adverse events was observed in seven studies. The main side effect of silver coatings was the development of argyria. For iodine coatings, only one anaphylactic case was reported as an adverse event. No systemic or other general side effects were reported for gentamicin. Conclusion: Clinical studies on the side effects of antibacterial coatings were limited. Based on the available outcomes, the most reported side effects of antibacterial coatings in clinical use were argyria with silver coatings. However, researchers should always pay attention to the potential side effects of antibacterial materials, such as systematic or local toxicity and allergy.

Effect of dental antiseptic agents on the viability of human periodontal ligament cells

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Cell viability is key for tissue regeneration.

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Dental antiseptics were cytotoxic in periodontal ligament cells.

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Real-time impedimetry proved to be a non-invasive method to monitor cell viability.

Objectives

We aimed to study whether or not various dental antiseptic agents affect the viability and proliferation of human periodontal ligament cells (PDLCs).

Materials and methods

Human PDLCs were isolated from a total of 10 surgically extracted impacted third molars and were.

cultured in-vitro. The cells were exposed to commonly used dental antiseptics, including chlorhexidine, cetylpyridinium chloride, triclosan, povidone-iodine and sodium bicarbonate for ultra-short-term (10, 20, 30 sec), short-term (10, 20, 30 min) and long-term (24, 48 h) at various concentrations. Cell morphology was observed with light microscopy. Cell viability was studied with impedimetric real-time xCELLigence and resazurin-based alamarBlue® assays. We used one-way ANOVA with Tukey’s and Bonferroni test (p < 0.05) for statistical analysis.

Results

Both alamarBlue® and xCELLigence analysis results were in agreement that ultra-short-term contact with cetylpyridinium chloride ≥ 0.01 mg/ml, chlorhexidine ≥ 1 mg/ml, triclosan ≥ 1 mg/ml and povidone-iodine ≥ 1 mg/ml as well as long-term exposure to cetylpyridinium chloride ≥ 0.001 mg/ml, chlorhexidine ≥ 0.01 mg/ml, triclosan ≥ 1 mg/ml, povidone-iodine ≥ 1 mg/ml and sodium bicarbonate ≥ 10 mg/ml was able to reduce the viability of human PDLCs significantly. According to the half-maximal inhibitory concentration (IC50) the rank of cytotoxicity was cetylpyridinium chloride > chlorhexidine > triclosan > povidone-iodine > sodium bicarbonate.

Conclusions

Our findings suggest that the tested antiseptic agents were cytotoxic to human PDLCs at lower than practically applied concentrations in dental interventions.

A novel chlorhexidine-hexametaphosphate coating for titanium with antibiofilm efficacy and stem cell cytocompatibility

Dental implants are an increasingly popular way to replace missing teeth. Whilst implant survival rates are high, a small number fail soon after placement, with various factors, including bacterial contamination, capable of disrupting osseointegration. This work describes the development of chlorhexidine-hexametaphosphate coatings for titanium that hydrolyse to release the antiseptic agent chlorhexidine. The aim was to develop a coating for titanium that released sufficient chlorhexidine to prevent biofilm formation, whilst simultaneously maintaining cytocompatibility with cells involved in osseointegration. The coatings were characterised with respect to physical properties, after which antibiofilm efficacy was investigated using a multispecies biofilm model, and cytocompatibility determined using human mesenchymal stem cells. The coatings exhibited similar physicochemical properties to some implant surfaces in clinical use, and significantly reduced formation of multispecies biofilm biomass up to 72 h. One coating had superior cytocompatibility, with mesenchymal stem cells able to perform normal functions and commence osteoblastic differentiation, although at a slower rate than those grown on uncoated titanium. With further refinement, these coatings may have application in the prevention of bacterial contamination of dental implants at the time of surgery. This could aid a reduction in rates of early implant failure.

Iodine Immobilized Metal-Organic Framework for NIR-Triggered Antibacterial Therapy on Orthopedic Implants

Iodine has been known as an effective disinfectant with broad-spectrum antimicrobial potency yet without drug resistance risk when used in clinic. However, the exploration of iodine for antibacterial therapy in orthopedics remains sparse due to its volatile nature and poor solubility. Herein, leveraging the superior absorption capability of metal-organic frameworks (MOFs) and their inherent photocatalytic properties, iodine-loaded MOF surface is presented to realize responsive iodine release along with intracellular reactive oxygen species(ROS) oxidation under near-infrared (NIR) exposure to achieve synergistic antibacterial effect. Iodine is successfully loaded using vapor deposition process onto zeolitic imidazolate framework-8(ZIF-8), which is immobilized onto micro arc oxidized titanium via a hydrothermal approach. The combination of NIR-triggered iodine release and ZIF-8 mediated ROS oxidative stress substantially augments the antibacterial efficacy of this approach both in vitro and in vivo. Furthermore, this composite coating also supported osteogenic differentiation of bone marrow stromal cells, as well as improved osseointegration of coated implants using an intramedullary rat model, suggesting improvement of antibacterial efficacy does not impair osteogenic potential of the implants. Altogether, immobilization of iodine via MOF on orthopedic implants with synergistic antibacterial effect can be a promising strategy to combat bacterial infections.

Why Irrigate for the Same Contamination Rate: Wound Contamination in Pediatric Spinal Surgery Using Betadine Versus Saline

BACKGROUND

The risk of surgical site infection in pediatric posterior spine fusion (PSF) is up to 4.3% in idiopathic populations and 24% in patients with neuromuscular disease. Twenty-three percent of pediatric PSF tissue cultures are positive before closure, with a higher rate in neuromuscular patients. Our primary aim was to evaluate the feasibility of a complete randomized controlled trial to study the efficacy of surgical site irrigation with povidone-iodine (PVP-I) compared with sterile saline (SS) to reduce the bacterial contamination rate before closure in children undergoing PSF.

METHODS

One hundred seventy-five subjects undergoing PSF were enrolled in a multicenter, single-blind, pilot randomized controlled trial. We recruited patients at low-risk (LR) and high-risk (HR) for infection 3:1, respectively. Before closure, a wound culture was collected. Nonviable tissues were debrided and the wound was soaked with 0.35% PVP-I or SS for 3 minutes. The wound was then irrigated with 2 L of saline and a second sample was collected.

RESULTS

One hundred fifty-three subjects completed the protocol. Seventy-seven subjects were allocated to PVP-I (18 HR, 59 LR) and 76 to SS (19 HR, 57 LR). Cultures were positive in 18% (14/77) of PVP-I samples (2 HR, 12 LR) and in 17% (13/76) of SS samples (3 HR, 10 LR) preirrigation and in 16% (12/77) of PVP-I samples (5 HR, 7 LR) and in 18% (14/76) of SS samples (4 HR, 10 LR) postirrigation. Eight percent (3/37) HR subjects (1 PVP-I, 2 SS) experienced infection at 30 days postoperative. No LR subjects experienced infection.

CONCLUSIONS

Positive cultures were similar across treatment and risk groups. The bacterial contamination of wounds before closure remains high regardless of irrigation type. A complete randomized controlled trial would be challenging to adequately power given the similarity of tissue positivity across groups.

LEVEL OF EVIDENCE

Level II-pilot randomized controlled trial.

Effects of different decontaminating solutions used for the treatment of peri-implantitis on the growth of Porphyromonas gingivalis-an in vitro study

Implants have been considered the treatment of choice to replace missing teeth, unfortunately, peri-implant disease is still an unresolved issue. Contaminated implants may be decontaminated by physical debridement and chemical disinfectants; however, there is a lack of consensus regarding the ideal techniques/agents to be used for the decontamination. The objective of our study was to compare the decontaminating efficacy of different chemical agents on a titanium surface contaminated with Porphyromonas gingivalis, a typical representative of the bacterial flora associated with peri-implantitis. Commercially pure Ti grade 4 discs with a polished surface were treated with a mouthwash containing chlorhexidine digluconate (0.1%), povidone-iodine (PVP-iodine) solution (10%) or citric acid monohydrate (40%). Qualitative and quantitative assessment of cellular growth and survival were assessed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and scanning electron microscopy (SEM). Significant differences in the quantity of P. gingivalis could be observed after 6 days of incubation. A numerical, but not statistically significant (P = 0.066) decrease in the amount of living bacteria was observed in the group treated with the PVP-iodine solution as compared to the control group. The chlorhexidine (CHX)-treated group presented with significantly higher cell counts, as compared to the PVP-iodine-treated group (P = 0.032), while this was not observed compared to the control group and citric acid-treated group. Our results have also been verified by SEM measurements. Our results suggest that for P. gingivalis contamination on a titanium surface in vitro, PVP-iodine is a superior decontaminant, compared to citric acid and chlorhexidine-digulconate solution.

Combination of ultrasonic decontamination, soft tissue curettage, and submucosal air polishing with povidone-iodine application for non-surgical therapy of peri-implantitis: 12 Month clinical outcomes

BACKGROUND

The aim of this study is to evaluate clinical outcomes of a concept for non-surgical peri-implantitis combining stepwise mechanical debridement measures with adjuvant povidone-iodine application with and without systemic antibiotics.

METHODS

Forty-five patients with chronic periodontitis and a total of 164 screw-typed implants with peri-implantitis were included. Peri-implantitis was defined as radiographic bone loss of > 2 mm, probing depth (PD) ≥5 mm with bleeding on probing (BOP). Stepwise treatment of implants was performed with ultrasonic debridement, soft tissue curettage (STC), glycine powder air polishing (GPAP), and a repeated submucosal application of povidone-iodine. Teeth with PD > 4 mm were treated simultaneously according to the same concept except STC. In cases with severe periodontitis (n = 24), amoxicillin and metronidazole (AM) were prescribed for 7 days.

RESULTS

After 12 months, implants treated without AM showed significant reductions (P < 0.05) of mean PD (1.4 ± 0.7 mm), clinical attachment level (CAL) (1.3 ± 0.8 mm), and BOP (33.4% ± 17.2%). In deep pockets (PD > 6 mm) changes of mean PD (2.3 ± 1.3 mm), CAL (2.0 ± 1.6 mm), and BOP (44.0% ± 41.7%) were more pronounced. Intake of AM did not significantly influence the changes in these parameters. However, the reduction of implant sites with PD > 4 mm and BOP was significantly higher in patients with AM than in those without AM (31.8% ± 12.6% versus 20.8% ± 14.7%; P < 0.05).

CONCLUSIONS

The combination of ultrasonic debridement, STC, and GPAP with adjuvant povidone-iodine led to significant clinical improvements at implants. Systemic antibiotics had limited effects on the reduction of persisting implant sites with treatment need.

Cerium Chloride Application Promotes Wound Healing and Cell Proliferation in Human Foreskin Fibroblasts

This study investigated the effect of cerium chloride (CeCl₃) on cell migration and gene expression of human foreskin fibroblasts (HFF). HFF were exposed to three different CeCl₃ solutions (1%, 5% and 10%, w/v %) for three different time durations (1, 5 and 10 min). 72 h after exposure to CeCl₃, cell viability was assessed by MTT test. A scratch-wounded assay determined the cell migration and the width of the wound, measured at 24 h. Gene expression patterns for cyclins B1, D1 and E1 were analyzed by RT-PCR (p < 0.05, t-test). The viability proliferation increased at 1- and 5-min exposures for all CeCl₃ concentrations, in contrast to no treatment (p < 0.05 at 24 h). No influence of CeCl₃ was found after 10 min. The scratch assay showed increased cell migration up to 60% at 1 and 5 min after 24 h at 5% and 10%. Cyclin B1, D1 and E1 all showed upregulation, confirming an increase in cell proliferation. This study demonstrates that exposure time and concentration of CeCl₃ may have a positive effect on fibroblast viability and migration. Application of CeCl₃ may be beneficial as a cell-stimulating agent leading to therapeutic tissue fibrosis or more resistant tissue around teeth, when warranted, during different periodontal therapies.

Effects of polyvinylpyrrolidone-iodine on tendon-bone healing in a rabbit extra-articular model

Polyvinylpyrrolidone-iodine (PVP-I) is a broad-spectrum antimicrobial agent, but its effects on tendon-bone healing are unclear. The purpose of this study was to investigate the effects of PVP-I on bone marrow mesenchymal stem cells (BMSCs) in vitro and on tendon-bone healing in vivo. In this study, following investigation of the concentration-dependent effects of PVP-I on the viability and osteogenic differentiation of BMSCs, the appropriate concentration of PVP-I was selected for animal experiments. New Zealand white rabbits received autologous tendon transplantation with and without PVP-I treatment of the graft tendon. Subsequently, histological examination, biomechanical testing and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses were conducted. At 6 weeks post-surgery, connective tissue and osteogenesis was observed at the tendon-bone interface in the PVP-I group. At 12 weeks post-surgery, the interface width in the PVP-I group was much narrower compared with that of the control group. Furthermore, the biomechanical properties of the PVP-I group were significantly stronger than those in the control group (P<0.05). RT-qPCR examination revealed that the mRNA levels of bone morphogenetic protein-2 and osteopontin in the PVP-I group were higher than those in the control group at 6 weeks (P<0.05). In conclusion, these results indicated that PVP-I promoted tendon-bone healing via osteogenesis.

Response of human dental pulp cells to a silver-containing PLGA/TCP-nanofabric as a potential antibacterial regenerative pulp-capping material

Background

Damage or exposure of the dental pulp requires immediate therapeutic intervention.

Methods

This study assessed the biocompatibility of a silver-containing PLGA/TCP-nanofabric scaffold (PLGA/Ag-TCP) in two in vitro models, i.e. the material adapted on pre-cultured cells and cells directly cultured on the material, respectively. Collagen saffolds with and without hyaluronan acid (Coll-HA; Coll) using both cell culturing methods and cells growing on culture plates served as reference. Cell viability and proliferation were assessed after 24, 48, and 72 h based on formazan formation and BrdU incorporation. Scaffolds were harvested. Gene expression of interleukin(IL)-6, tumor necrosis factor (TNF)-alpha, and alkaline phosphatase (AP) was assessed 24 h after stimulation.

Results

In both models formazan formation and BrdU incorporation was reduced by PLGA/Ag-TCP on dental pulp cells, while no significant reduction was found in cells with Coll and Coll-HA. Cells with PLGA/Ag-TCP for 72 h showed similar relative BrdU incorporation than cells stimulated with Coll and Coll-HA. A prominent increase in the pro-inflammatory genes IL-6 and TNF-α was observed when cells were cultured with PLGA/Ag-TCP compared to the other groups. This increase was parallel with a slight increase in AP expression. Overall, no differences between the two culture methods were observed.

Conclusions

PLGA/Ag-TCP decreased viability and proliferation rate of human dental pulp cells and increased the pro-inflammatory capacity and alkaline phosphatase expression. Whether these cellular responses observed in vitro translate into pulp regeneration in vivo will be assessed in further studies.

Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

Allografts eliminate the disadvantages associated with autografts and synthetic scaffolds but are associated with a disease-transmission risk. Therefore, allograft sterilisation is crucial. We aimed to determine whether polyvinylpyrrolidone-iodine (PVP-I) can be used for sterilisation and as a new wet-preservation method. PVP-I-sterilised and preserved allografts demonstrated improved mechanical property, osteogenesis, and excellent microbial inhibition. A thigh muscle pouch model of nude mice showed that PVP-I-preserved allografts demonstrated better ectopic formation than Co₆₀-sterilised allografts (control) in vivo (P < 0.05). Furthermore, the PVP-I-preserved group showed no difference between 24 h and 12 weeks of allograft preservation (P > 0.05). PVP-I-preserved allografts showed more hydrophilic surfaces and PVP-I-sterilised tendons showed higher mechanical strength than Co₆₀-sterilised tendons (P < 0.05). The level of residual PVP-I was higher without washing and with prolonged preservation (P < 0.05). In vitro cellular tests showed that appropriate PVP-I concentration was nontoxic to preosteoblast cells, and cellular differentiation measured by alkaline phosphatase activity and osteogenic gene markers was enhanced (P < 0.05). Therefore, the improved biological performance of implanted allografts may be attributable to better surface properties and residual PVP-I, and PVP-I immersion can be a simple, easy method for allograft sterilisation and preservation.

Effect of povidone iodine and hydrogen peroxide on fracture healing: a histomorphometric study on rats

PURPOSE

To evaluate the effect of povidone iodine and hydrogen peroxide on fracture healing in a rat model.

METHODS

The middle section of the right femur of 36 male Sprague Dawley rats was osteotomised with a saw. In the control group (n=9), the wound was irrigated with 100 ml 0.9% saline. In the 10% povidone iodine (n=9), 1% povidone iodine (n=9), and 3% hydrogen peroxide (n=9) groups, the wound was completely soaked with the respective solution for 2 minutes, and then irrigated with 100 ml saline. The osteotomy was fixed with an intramedullary Kirschner wire. Rats were euthanised at week 1, 2, and 5. In each femur, the percentage area of osseous, cartilaginous, and fibrous tissue in the callus was evaluated in 3 slides (one median and 2 paramedian).

RESULTS

The control group differed significantly to the other 3 groups (p=0.023 to p<0.001) in weeks 1, 2, and 5, except for the 1% povidone iodine group in terms of percentage of osseous (p=0.349) and fibrous (p=0.999) tissue. The healing process was similar in the 1% povidone iodine group and the control group, whereas healing was impaired in the 10% povidone iodine group and 3% hydrogen peroxide group, as indicated by the lower percentage of osseous tissue, higher percentage of fibrous tissue, and increased percentage of cartilaginous tissue between weeks 2 and 5 (delayed bone healing).

CONCLUSION

The 1% povidone iodine solution is recommended as the irrigation adjuvant in fracture surgery.

Incorporation of bioactive polyvinylpyrrolidone-iodine within bilayered collagen scaffolds enhances the differentiation and subchondral osteogenesis of mesenchymal stem cells

Polyvinylpyrrolidone-iodine (Povidone-iodine, PVP-I) is widely used as an antiseptic agent for lavation during joint surgery; however, the biological effects of PVP-I on cells from joint tissue are unknown. This study examined the biocompatibility and biological effects of PVP-I on cells from joint tissue, with the aim of optimizing cell-scaffold based joint repair. Cells from joint tissue, including cartilage derived progenitor cells (CPC), subchondral bone derived osteoblast and bone marrow derived mesenchymal stem cells (BM-MSC) were isolated. The concentration-dependent effects of PVP-I on cell proliferation, migration and differentiation were evaluated. Additionally, the efficacy and mechanism of a PVP-I loaded bilayer collagen scaffold for osteochondral defect repair was investigated in a rabbit model. A micromolar concentration of PVP-I was found not to affect cell proliferation, CPC migration or extracellular matrix production. Interestingly, micromolar concentrations of PVP-I promote osteogenic differentiation of BM-MSC, as evidenced by up-regulation of RUNX2 and Osteocalcin gene expression, as well as increased mineralization on the three-dimensional scaffold. PVP-I treatment of collagen scaffolds significantly increased fibronectin binding onto the scaffold surface and collagen type I protein synthesis of cultured BM-MSC. Implantation of PVP-I treated collagen scaffolds into rabbit osteochondral defect significantly enhanced subchondral bone regeneration at 6 weeks post-surgery compared with the scaffold alone (subchondral bone histological score of 8.80±1.64 vs. 3.8±2.19, p<0.05). The biocompatibility and pro-osteogenic activity of PVP-I on the cells from joint tissue and the enhanced subchondral bone formation in PVP-I treated scaffolds would thus indicate the potential of PVP-I for osteochondral defect repair.

Role of povidone iodine in periapical surgeries: Hemostyptic and anti-inflammatory?

INTRODUCTION

Periapical surgery needs asepsis, a bloodless field for ensuring success of the treatment. Efficacy of Povidone Iodine (PVI) in the elimination of pathogen causing periapical lesions is well established. PVI is also widely used as a disinfectant, sclerosing agent, styptic as well as an anti-odematous agent.

MATERIALS AND METHODS

This prospective pilot study done on 20 males between 20-40 years age group with periapical lesions in single rooted maxillary anterior tooth of 1-2 cm in diameter. The bleeding time, clotting time, bleeding time at the apex, drugs used and visual analogue scale of oedema on postoperative days were obtained. Descriptive statistics, paired t test and independent t-test were used.

RESULTS AND CONCLUSION

Results show a statistically significant reduction in the time required to achieve a bloodless field and a marked decrease in oedema in the first and second postoperative days resulting in lesser consumption of NSAIDs. In conclusion, the effect of PVI in periapical surgery seems to reduce the bleeding time at apex, total dose of NSAIDs used, oedema on first two postoperative days with high statistical significance. Hence the routine use of saline in periapical surgeries may be effectively substituted with PVI. The finding of this pilot study has to be evaluated using wider samples for effective clinical translations.

Stemness characteristics and osteogenic potential of sheep amniotic epithelial cells

We set out to characterize stemness properties and osteogenic potential of sheep AEC (amniotic epithelial cells). AEC were isolated from 3-month-old fetuses and expanded in vitro for 12 passages. The morphology, surface markers, stemness markers and osteogenic differentiation were inspected after 1, 6 and 12 passages of expansion, with an average doubling time of 24 h. AEC clearly expressed the stemness markers Oct-3/4 (octamer-binding protein-3/4), Nanog, Sox2 and TERT (telomerase reverse transcriptase) and displayed low levels of global DNA methylation. Culture had moderate effects on cell conditions; some adhesion molecules progressively disappeared from the cell surface, and the expression of Sox2 and TERT was slightly reduced while Nanog increased. No changes occurred in the levels of DNA methylation. Cells organized in 3D spheroids were used for IVD (in vitro differentiation). Within these structures the cells developed a complex intercellular organization that involved extensive intercellular coupling despite continuous cell migration. Marked deposition of calcein in the ECM (extracellular matrix), increased ALP (alkaline phosphatase) activity, expression of bone-related genes (osteocalcin) and the matrix mineralization shown by Alizarin Red staining demonstrate that AEC can undergo rapid and extensive osteogenic differentiation. AEC introduced in experimental bone lesions survived in the site of implantation for 45 days and supported consistent bone neoformation, thus showing promising potential applications in osteogenic regenerative medicine.

Surgical site infection after pediatric spinal deformity surgery

The incidence of surgical site infection (SSI) after spinal deformity surgery for adolescent idiopathic scoliosis ranges from 0.5-6.7%. The risk of infection following spinal fusion in patients with neuromuscular scoliosis is greater, with reported rates of 6.1-15.2% for cerebral palsy and 8-41.7% for myelodysplasia. SSIs result in increased patient morbidity, multiple operations, prolonged hospital stays, and significant financial costs. Recent literature has focused on elucidating the most common organisms involved in SSIs, as well as identifying modifiable risk factors and prevention strategies that may decrease the rates of infection. These include malnutrition, positive urine cultures, antibiotic prophylaxis, surgical site antisepsis, antibiotic-loaded allograft, local application of antibiotics, and irrigation solutions. Acute and delayed SSIs are managed differently. Removal of instrumentation is required for effective treatment of delayed SSIs. This review article examines the current literature on the prevention and management of SSIs after pediatric spinal deformity surgery.

A comparison of five treatment protocols for contaminated bone grafts in reference to sterility and cell viability

BACKGROUND

Occasionally, a bone graft or comminuted fracture fragment is dropped on the operating-room floor and becomes contaminated. The purpose of this study was to determine an optimal method for sterilizing this bone with the minimum sacrifice of cell viability.

METHODS

A set of discarded bone samples was taken from a series of twenty total knee arthroplasty operations. The bone samples were uniformly contaminated with use of a bacterial broth prepared from culture samples taken from the operating-room floor. The bone samples in each set underwent five different decontamination procedures. Specifically, one sample in each set was autoclaved and four other samples underwent mechanical agitation in normal saline solution, 2% chlorhexidine gluconate, or 10% povidone-iodine (which was either left wet or was dried). Positive and negative controls were used for comparison. Ten sets were then cultured to determine sterility, and ten underwent live/dead trypan blue staining to determine cell viability.

RESULTS

Autoclaving, chlorhexidine gluconate, and dry povidone-iodine sterilized all samples; wet povidone-iodine decontaminated four (40%) of ten samples; and saline solution sterilized none. While all decontamination methods reduced the cell count to some extent, autoclaving and chlorhexidine gluconate left no viable cells. When the cell counts were expressed as a percentage of the control value, dry povidone-iodine sterilization maintained significantly fewer live cells than controls (21%; p < 0.01), whereas saline solution and wet povidone-iodine were not significantly different from controls (77% and 66%; p = 0.40 and p = 0.22, respectively).

CONCLUSIONS

Of the easily accessible protocols studied, mechanical agitation and serial washes of bone graft in povidone-iodine that is allowed to dry offers the best balance between complete sterilization of contaminated bone and maintenance of tissue viability.