The therapeutic perspective of cold atmospheric plasma in periodontal disease.

OBJECTIVES: Periodontal disease (PD) is one of the most common infectious diseases with complex inflammatory conditions, having irreversibly destructive impacts on the periodontal supporting tissues. The application of cold atmospheric plasma (CAP) is a promising adjuvant therapy modality for PD. However, the mechanism of CAP in PD treatment is still poorly understood. The review motivates to outline the latest researches concerning the applications of CAP in PD treatment. METHODS: We searched CAP-related literature through utilizing the well-established databases of Pubmed, Scopus and Web of Science according to the following keywords related to periodontal disease (periodontal, gingival, gingivitis, gingiva, periodontium, periodontitis). RESULTS: A total of 18 concerning original studies were found. These studies could be classified according to three pathophysiological perspectives of PD. The therapeutic mechanisms of CAP may be attributed to the oxidative stress-related cell death of periodontal bacteria, the suppression of periodontal inflammation and pro-inflammatory cytokine secretion, as well as the acceleration of periodontal soft tissue wound healing and hard tissue reconstruction. CONCLUSIONS: Cold atmospheric plasma has potential therapeutic effects on PD through three mechanisms: antimicrobial effect, inflammation attenuation, and tissue remodeling. This review hopefully provides a comprehensive perspective into the potential of CAP in PD therapy.

Prognostic Evaluation for Oral Squamous Cell Carcinoma: A Novel Method Based on m6A Methylation Regulators.

OBJECTIVE: This study aimed to examine a novel method for prognostic evaluation of patients with oral squamous cell carcinoma (OSCC) based on the expression of heterogeneous nuclear ribonucleoprotein C (HNRNPC), YTH domain-binding protein 2 (YTHDF2), and methyltransferase 14 (METTL14). METHODS: We obtained the RNA sequence and clinical information of OSCC patients from The Cancer Genome Atlas database. An optical method was established by the least absolute shrinkage and selection operator Cox regression algorithm, which was used to calculate the risk score of every sample. In addition, all samples (n=239) were classified into high-risk (n=119) and low-risk (n=120) groups, and the overall survival (OS) time and clinical characteristics were compared between groups. Moreover, bioinformatics analysis was carried out. Gene set enrichment analysis was performed to investigate the signaling pathways of HNRNPC, YTHDF2, and METTL14. RESULTS: The two groups showed significantly different OS time, tumor grades, tumor stages, and pathologic T stages (P<0.05). The receiver operating characteristic analysis identified that our method was effective and it was more accurate than use of age, gender, tumor grade, tumor stage, pathologic T stage, and pathologic N stage in OSCC prognostic prediction. Gene set enrichment analysis revealed that HNRNPC, YTHDF2, and METTL14 were mainly associated with ubiquitin-mediated proteolysis, cell cycle, RNA degradation, and spliceosome signaling pathways. CONCLUSION: The method based on the expression of HNRNPC, YTHDF2, and METTL14 can predict the prognosis of patients with OSCC independently, and its prognostic value is better than that of clinicopathological characteristic indicators.

Antibacterial and physical properties of EGCG-containing glass ionomer cements.

OBJECTIVES: To evaluate the effect of the addition of epigallocatechin-3-gallate (EGCG) on the antibacterial and physical properties of glass ionomer cement (GIC). METHODS: A conventional GIC, Fuji IX, was used as a control. EGCG was incorporated into GIC at 0.1% (w/w) and used as the experimental group. Chlorhexidine (CHX) was added into GIC at 1% (w/w) as a positive control. The anti-biofilm effect of the materials was assessed by a colorimetric technique (MTT assay) and scanning electron microscopy (SEM). The leaching antibacterial activity of the materials on Streptococcus mutans was evaluated by an agar-diffusion test. The flexural strength of the materials was evaluated using a universal testing machine and the surface microhardness was measured using a microhardness tester. The fluoride-releasing property of the materials was tested by ion chromatography. RESULTS: The optical density (OD) values of the GIC-EGCG group were significantly decreased at 4h compared with the GIC group, but only a slightly decreased tendency was observed at 24h (P>0.05). No inhibition zones were detected in the GIC group during the study period. Significant differences were found between each group (P<0.05). Compared with the control group, there was a significant increase in the flexural strength and surface microhardness for the GIC-EGCG group (P<0.05). The fluoride ion release was not influenced by EGCG-incorporation (P>0.05). CONCLUSIONS: These findings suggested that GIC-containing 0.1% (w/w) EGCG is a promising restorative material with improved mechanical properties and a tendency towards preferable antibacterial properties. CLINICAL SIGNIFICANCE: Modification of the glass ionomer cements with EGCG to improve the antibacterial and physical properties showed some encouraging results. This suggested that the modification of GIC with EGCG might be an effective strategy to be used in the dental clinic. However, this was only an in vitro study and clinical trials would need to verify true outcomes.

Effect of desensitising paste containing 8% arginine and calcium carbonate on biofilm formation of Streptococcus mutans in vitro.

OBJECTIVES: To evaluate the influence of desensitising paste containing 8% arginine and calcium carbonate (Ar-Ca) on biofilm formation on dentine. METHODS: Dentine discs were cut from extracted third molars and divided into the following three groups: no treatment, pumice treatment and Ar-Ca treatment. Surface topography and roughness were examined using scanning electron microscopy (SEM) and non-contact 3D surface profiler. After sterilisation, samples were incubated with Streptococcus mutans (S. mutans) for 4 h, 24 h and 72 h. Bacterial adhesion and biofilm formation were analysed using SEM, whereas MTT and lactic acid production assays were used to analyse the metabolic activity of S. mutans. RESULTS: After polishing with either pumice or Ar-Ca, the surfaces of the samples became smoother than in the control group. The Ra values of the three experimental groups decreased significantly to 0.43 µm, 0.3 µm and 0.26 µm, respectively. Compared to the control group, fewer bacteria adhered to the dentine surface in the Ar-Ca group, while biofilm thickness decreased significantly for both groups after incubating for 24 h and 72 h. MTT and lactic acid production levers also showed a significant reduction in the Ar-Ca group. CONCLUSIONS: Ar-Ca appears to present antibiofilm efficacy and may provide a promising approach to combat bacterial infection in hypersensitive dentinal lesions. CLINICAL SIGNIFICANCE: As a clinical application of desensitising polishing paste, the paste containing 8% arginine and calcium carbonate could also inhibit the biofilm formation effectively.

Effect of pretreatment with calcium-containing desensitizer on the dentine bonding of mild self-etch adhesives.

Desensitizing agents are frequently applied to sensitive teeth and may affect subsequent resin bonding. The current study aimed to evaluate the bonding performance of two self-etch adhesives containing functional monomers to dentine pretreated with three new calcium-containing desensitizers. No desensitizer was applied in the control group. Groups 1, 2, and 3 were treated with an arginine-calcium carbonate-containing polishing paste, a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-containing paste, and an experimental hydroxyapatite paste, respectively. G-Bond and Clearfil S(3) Bond were used for bonding after desensitizer treatments. The microtensile bond strength (µTBS) was tested (n = 20 beams per group) and failure mode distribution was analyzed. Scanning electron microscopy was used to observe the occlusion of dentinal tubules. The mean (±SD) µTBS values, expressed in MPa, of groups 1, 2, and 3 and the control group were, respectively, 30.81 (7.79), 44.41 (8.02), 31.49 (6.13), and 41.40 (8.67) for G-Bond and 39.63 (9.59), 32.55 (7.86), 37.50 (8.60), 27.90 (6.52) for S3 Bond. Most failures were recorded as adhesive failure (69.375%), instead of cohesive failure or mixed failure. The dentinal tubules were seldom plugged in group 2, but were mostly occluded in groups 1 and 3. Two-way anova indicated that desensitizer application in association with a compatible adhesive system should be used when endeavoring to control hypersensitivity without adverse interference in bonding.

[Clinical problems and their managements in dental bonding procedure].

Dental bonding technique has become an essential technique for dental clinical practice over the past several decades. Dental adhesion is widely used in direct and indirect restorations. However, problems such as technique sensitivity, postoperative sensitivity, secondary caries and marginal discoloration always appear in the dental bonding procedures. Fiber post and all-ceramic restoration bonding are essential step in esthetic dentistry. If these problems are not well handled, it will result in failure of the restorations. Therefore, the aim of this article is to provide adequate consultations and advice for the clinical practitioners based on the author's experience and relevant literatures.

Effect of an 8.0% arginine and calcium carbonate in-office desensitizing paste on the microtensile bond strength of self-etching dental adhesives to human dentin.

PURPOSE: To evaluate in the laboratory the effect of an 8.0% arginine and calcium carbonate desensitizing paste in occluding open dentin tubules and examine the effect of bonding between the adhesive agents and dentin after being treated with the desensitizing paste. METHODS: Two self-etching adhesives were used. Intact human premolars extracted for orthodontic reasons were used within 3 months of extraction. The occlusal enamel was removed and dentin slices were polished. The dentin tubules were opened by etching with a 1% citric acid solution for 20 seconds to simulate a postoperative sensitivity model. Then the specimens were randomly assigned into five groups. Group A: specimens without any treatment (control). Group B: specimens were polished with a slurry (SiO2) for 30 seconds. Groups C, D and E: 8.0% arginine and calcium carbonate desensitizing paste was applied. Specimens in Group C were polished for 3 seconds, and then repeated for another 3 seconds for a total of 6 seconds, according to the manufacturer's instructions: specimens in Group D were polished twice for 9 seconds for a total of 18 seconds; and specimens in Group E were treated for an extended time of 30 seconds. Each group was randomly divided into two sub-groups in order to evaluate the effect on two different adhesive agents. A one-step self-etching adhesive agent (G-Bond) and a two-step self-etching adhesive agent (F1-Bond II) were applied following the manufacturers' instructions. Then microtensile bond strengths of the 10 groups were tested. SEM was used to evaluate the laboratory effect of the desensitizing paste in occluding open dentin tubules. Statistical analysis was carried out using SPSS version 16.0. RESULTS: The SEM observations showed that the 8.0% arginine and calcium carbonate desensitizing paste could occlude the dentin tubules effectively, and thus may have potential benefits in preventing postoperative sensitivity based on the hydrodynamic theory. An extended application time of 18 or 30 seconds showed no adverse effect of the desensitizing paste on the bonding performance to dentin when using self-etching adhesives containing functional monomers such as 4-MET like G-Bond.

Epigallocatechin-3-gallate (EGCG) enhances the therapeutic activity of a dental adhesive.

OBJECTIVES: The purpose of this study was to evaluate the antibacterial potential and physicochemical properties of a dental adhesive incorporated with epigallocatechin-3-gallate (EGCG) in different concentration over time. METHODS: EGCG was incorporated at a ratio of 100, 200, and 300 µg/ml into a dental adhesive. The effects of the cured adhesives on the growth of Streptococcus mutans were determined by direct contact test immediately or one month later and by scanning electron microscopy (SEM), respectively. Microtensile bond strength (µTBS) test was used to test the mechanical property of the adhesives immediately or six months later. The degree of conversion (DC) of the adhesives was evaluated by Fourier transform infrared spectroscopy (FTIR). RESULTS: Compared with negative control, the 200 µg/ml and 300 µg/ml EGCG-incorporated dental adhesive were found to exhibit inhibitory effect on the growth of S. mutans. The µTBS of the EGCG-incorporated dental adhesive was higher than the control. The DC of the adhesive system was not affected by the addition of EGCG. CONCLUSIONS: 200 µg/ml EGCG incorporated dental adhesives could accomplish therapeutic goals that play in antimicrobial function whilst keeping the durability of resin-dentine bond.

Effect of ethanol-wet bonding with hydrophobic adhesive on caries-affected dentine.

Frequently encountered in clinical practice, caries-affected dentine (CAD) is the most challenging bonding substrate. This study evaluated the effect of ethanol-wet bonding with hydrophobic adhesive to sound dentine and to CAD. In the control groups, prepared sound dentine and CAD were bonded with Adper Single Bond 2 using a traditional water-wet bonding technique. In the experimental groups, the specimens were treated as follows: Group 1, rinsed with stepwise ethanol dehydration; Group 2, immersion in 100% ethanol, three times, for 20 s each time; and Group 3, immersion in 100% ethanol for 20 s. Microtensile bond strength (µTBS) testing was used to evaluate the effects of the different protocols on bonding. The microhardness of debonded dentine surfaces was measured to ensure the presence of CAD. Interfacial nanoleakage was evaluated by field-emission scanning electron microscopy. Treatment significantly improved the µTBS in CAD in Groups 1 and 2, but had no effect on Group 3. Conversely, treatment significantly reduced the µTBS in sound dentine in Groups 2 and 3, but had no effect in Group 1. The presence of nanoleakage varied with the ethanol-wet protocol used. In conclusion, ethanol-wet bonding can potentially improve bond efficacy to CAD when an appropriate protocol is used.