Overexpression of methyltransferase-like 3 and 14 in oral squamous cell carcinoma.

OBJECTIVES: This study aimed to determine expressions of methyltransferase-like 3 (METTL3) and METTL14, two enzymes essential for mRNA methylation at the adenosine (m6 A), in oral squamous cell carcinoma (OSCC) and to investigate in vitro aggressiveness of their aberrant expressions. METHODS: METTL3 and METTL14 expressions in 50 OSCC and 11 normal oral tissues were examined by immunohistochemistry. METTL3 and METTL14 expressions and m6 A amounts were determined in three OSCC cell lines, including HN5, HN6, and HN15. Cell proliferation, migration, and invasion were studied by BrdU, wound healing, and Transwell chamber assays, after silencing of METTL3, METTL14, or both by siRNA transfection. RESULTS: Immunostaining of METTL3 and METTL14 was localized in cancer cell nuclei. The mean percentages of METTL3- and METTL14-positive cells were significantly increased in OSCC tissues (p < 0.001). The percentages of METTL3- and METTL14-positive cells were correlated with the advanced pTNM stages (p < 0.05) and with the degrees of histopathological differentiation in OSCC (r = 0.564 and r = 0.316, respectively; p < 0.001). By the COX multivariate analysis, both overexpressed METTL3 and METTL14 were significantly associated with short overall survival (p < 0.05). Both METTL3 and METTL14 expressions and the m6 A amounts were significantly increased in HN6 (p < 0.05). Silencing of METTL3 and METTL14 in HN6 significantly inhibited cell proliferation (p < 0.01), but it failed to mitigate cell migration or invasion. CONCLUSIONS: METTL3 and METTL14 are overexpressed in OSCC tissues and in the HN6 OSCC cell line that promotes cell proliferation. Overexpressed METTL3 or METTL14 is found to be an independent prognostic factor for short overall survival in patients with OSCC.

Evaluation of the Bond Strength of Epoxy Resin-based Sealer Following Different Calcium Hydroxide Paste Removal Methods in Oval-shaped Root Canal.

AIM: The study aimed to investigate the bond strength of epoxy resin-based sealer following five different calcium hydroxide paste removal methods in oval-shaped root canals. MATERIALS AND METHODS: Sixty single-rooted human mandibular premolars having an oval-shaped root canal as evidenced by radiographs were decoronated and instrumented to size 40/0.04, medicated with calcium hydroxide paste for 7 days, before being randomly assigned to the conventional needle irrigation (CNI), manual dynamic agitation (MDA), sonic irrigation (SI), passive ultrasonic irrigation (PUI), and XP-endo Finisher (XP) groups to be irrigated using different irrigation systems. All specimens were then obturated using an epoxy resin-based root canal sealer and warm vertical compaction obturation technique. After 7 days, each specimen was sectioned into 1 mm root slices at the coronal, middle, and apical third of the root canal and tested for the push-out bond strength using a universal testing machine. RESULTS: The XP group was the only group that had comparable bond strength to the control group at every level of the root canal following removal of calcium hydroxide medicament (p >0.05). The control group had higher bond strength than the CNI group at every level of the root canal (p < 0.05). CONCLUSION: Calcium hydroxide interfered with the bonding of epoxy resin-based sealer to root canal walls. Irrigation with the XP increased the bonding sealer at every level of the root canal. CLINICAL SIGNIFICANCE: The XP was efficacious as a final rinse agitation technique to promote the bonding of the epoxy resin-based sealer at every level of the root canal following calcium hydroxide medication.

Involvement of the A disintegrin and metalloproteinase 9 in oral cancer cell invasion.

The aims of this study were to determine the functional roles of the transmembrane glycoprotein, Disintegrin and metalloproteinase domain-containing protein 9 (ADAM 9), in the phosphorylation of epidermal growth factor receptor (EGFR) and AKT and in the aggressiveness of oral cancer cells. Immunohistochemistry and immunoblotting were conducted to determine expression of ADAM 9 and the levels of EGFR phosphorylated at the tyrosine 1173 residue (p-EGFRtyr1173 ) and AKT phosphorylated at the serine 473 residue (p-AKTser473 ) in oral cancer tissues and in the oral cancer cell lines HN5, HN6, HN15, and HN008. Small interfering RNA (siRNA) was used to inhibit expression of ADAM9 mRNA, and thus production of ADAM9 protein, in oral cancer cells. ADAM9-knockdown cells were examined for p-EGFRtyr1173 and p-AKTser473 levels and used for cell proliferation and invasion assays. A positive correlation among overexpression of ADAM 9, p-EGFRtyr1173 , and p-AKTser473 was found in oral cancer tissues. These biomolecules were also overexpressed in HN6 and HN15 cell lines. Expression of ADAM9 in HN6 and HN15 cells was statistically significantly inhibited by siRNA against ADAM9 mRNA (siADAM9) compared with the negative-control siRNA (scramble). The levels of p-AKTser473 , but not those of p-EGFRtyr1173 , were statistically significantly blocked by siADAM9. Although the proliferation rates of ADAM9 knocked-down HN6 and HN15 cells did not differ from those of cells exposed to scramble, a statistically significant decrease in cell invasion was found in these ADAM9-silenced cells. These results suggest a functional role of the ADAM 9/AKT signaling pathway in oral cancer cell invasion, which may be beneficial as a therapeutic target of oral cancer.

Significant elevation of salivary human neutrophil peptides 1-3 levels by probiotic milk in preschool children with severe early childhood caries: a randomized controlled trial.

OBJECTIVES: To determine salivary human neutrophil peptides 1-3 (HNP1-3) levels in caries-free preschool children and in those with early childhood caries (ECC) or severe-ECC, in a daily probiotic group, receiving reconstituted milk with the probiotic Lactobacillus paracasei SD1 once daily; a triweekly probiotic group, receiving the probiotic milk 3 days a week; and a placebo group. MATERIALS AND METHODS: Oral examination and unstimulated whole saliva collection were conducted in 354 children at baseline, 6 months after intervention (T6), and after probiotic discontinuation (T12). Of the 354, adequate volume of saliva samples from 268 children were simultaneously analyzed for Streptococcus mutans and total lactobacilli levels using qPCR and for HNP1-3 levels using ELISA. RESULTS: In the severe-ECC status, significant increases in the median HNP1-3 levels at T12 were found in both daily and triweekly probiotic groups (p < 0.001). The median S. mutans levels in the daily group were significantly decreased at T6 and T12 (p < 0.01), whereas the median total lactobacilli levels were significantly increased at T6 (p < 0.001). Significantly inverse correlations between altered HNP1-3 and S. mutans levels and significant decreases in caries progression were found in both probiotic groups (p < 0.05). CONCLUSIONS: In the severe-ECC status, daily or triweekly consumption of L. paracasei SD1 significantly enhanced salivary HNP1-3 levels, but reduced S. mutans levels, possibly resulting in reduction of caries progression. CLINICAL RELEVANCE: Significant enhancement of salivary HNP1-3 levels by probiotic consumption is associated with reduction in S. mutans levels, consistent with diminished caries progression in children with severe-ECC.

Anesthetic efficacies of intrapapillary injection in comparison to inferior alveolar nerve block for mandibular premolar extraction: a randomized clinical trial.

OBJECTIVE: Intrapapillary injection (IPI) has been suggested to improve pulpal anesthesia of mandibular teeth and to avoid complications from inferior alveolar nerve block (IANB). This study aimed to determine and compare clinical efficacies and prostaglandin E2 (PGE2) levels between IPI and IANB. MATERIALS AND METHODS: IANB was randomly selected for mandibular premolar anesthesia on one side of 40 patients, whereas IPI was locally administered to the contralateral premolar. Pulpal anesthesia, pain during injection and extraction, patients' satisfaction, and complications were assessed from 30 patients. Gingival crevicular fluid from ten patients was collected for PGE2 quantification by ELISA. RESULTS: Of 30 patients, 18 preferred IPI after injection due to significantly faster mean onset of pulpal anesthesia (p < 0.001) and lower mean score of injection pain (p = 0.017) than IANB, but 21 preferred IANB instead after extraction due to less postoperative pain, consistent with the significantly lower median PGE2 level on the IANB side than that on the IPI at 30 min (p = 0.047). However, there was no difference in the mean satisfaction score between the two techniques. Ulcerated epithelium and sloughing tissues were found at the IPI site in some patients with complete healing within 2 weeks. CONCLUSIONS: The anesthetic efficacies of IPI for mandibular premolar extraction are comparable to those of IANB. However, postoperative pain and local complications at the IPI site should be considered. CLINICAL RELEVANCE: IPI may be used for dental procedures that require only a short anesthetic duration to avoid failure of pulpal anesthesia, complications, and discomfort from IANB.

Pulpal anesthesia in pediatric patients following supplemental mandibular buccal infiltration in vital permanent mandibular molars with deep caries.

OBJECTIVES: Inferior alveolar nerve block (IANB) does not always provide adequate pulpal anesthesia, and supplemental techniques have been investigated in adults. This study aimed to pre- and intraoperatively evaluate the success of pulpal anesthesia following supplemental mandibular buccal infiltration (SMBI) after failure of IANB in permanent mandibular molars with deep caries of pediatric patients. MATERIALS AND METHODS: Following IANB, preoperative pulpal anesthesia was assessed using the cold test, and success was defined when there was a negative response. In cases with failed IANB, SMBI was administered, and pulpal anesthesia was re-evaluated. A maximum of three SMBIs was allowed. After achieving successful preoperative pulpal anesthesia, treatment was then initiated. Intraoperatively, success of pulpal anesthesia was determined when the Wong-Baker FACES Pain Rating Scale reported by the patients was ≤ four. RESULTS: Sixty molars of patients aged 9.6 ± 2.3 years were included in the study. The success of preoperative pulpal anesthesia following IANB was 33.3%. The overall cumulative preoperative pulpal anesthesia after three SMBIs was 95%. However, the success of intraoperative pulpal anesthesia was only 66.7%. CONCLUSIONS: SMBI greatly improved the success of preoperative pulpal anesthesia after failure of IANB. However, the success of preoperative pulpal anesthesia, confirmed by the cold test, does not always guarantee intraoperative pulpal anesthesia, especially in teeth with irreversible pulpitis. CLINICAL RELEVANCE: IANB produced low pulpal anesthesia in vital permanent mandibular molars with deep caries of pediatric patients. Clinicians should always prepare for supplemental injection both pre- and intra-operatively.

Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial.

OBJECTIVE: To investigate the effects of probiotics, Lactobacillus paracasei SD1, on the quantities of Streptococcus mutans in saliva and plaque samples of preschool children. DESIGN: This randomized trial recruited 487 preschool children from eight childcare centers. Participants were assigned to receive a 6-month course of placebo milk daily (group I), probiotic milk either daily (group II) or three days a week (triweekly, group III). The absolute quantities of S. mutans and total lactobacilli in the saliva and plaque samples at baseline (T0), after intervention (T6), and 6 months after discontinuation (T12) were assessed by qPCR. RESULTS: Of 487 children, 354 completed all follow-up periods. However, only 268 children (3.2 ± 0.8 years old; groups I = 86, II = 89, and III = 93) provided adequate saliva for qPCR. Whereas the quantities of S. mutans were significantly decreased in groups II and III compared to group I in the saliva and plaque samples at T6 and T12, those of total lactobacilli were significantly increased (p < 0.0167). There was no difference in the quantities of S. mutans or total lactobacilli between groups II and III at any period. Significant changes in the quantities of S. mutans and total lactobacilli lasted until T12 compared to T0 (p < 0.0167). CONCLUSIONS: Probiotic administration daily or triweekly reduces S. mutans quantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children. CLINICAL RELEVANCE: Daily or triweekly consumption of L. paracasei SD1 supplemented in milk may help prevent dental caries in preschool children.

O-GlcNAcylation in oral squamous cell carcinoma.

BACKGROUND: Two post-translational mechanisms commonly demonstrated in various cancers are protein phosphorylation and glycosylation by O-linked ß-N-acetylglucosamine (O-GlcNAc). However, only phosphorylation of the epidermal growth factor receptor (EGFR)/Akt pathway has been reported in oral squamous cell carcinoma (OSCC). Therefore, we aimed to determine both post-translational modifications in OSCC tissues and in oral cancer cells compared to normal tissues and oral keratinocytes and to find correlations of these modifications with histological grading. METHODS: Thirty-two OSCC and ten normal formalin-fixed and paraffin-embedded sections were probed with the anti-O-GlcNAc, anti-O-GlcNAc transferase (OGT), anti-phosphorylated-EGFRtyr1173 , and anti-phosphorylated-Aktser473 antibodies following standard immunohistochemistry. The immunohistochemical (IHC) score was determined using the Fromowitz standard. Whole cell lysates of oral cancer cells and normal oral keratinocytes were immunoblotted with the anti-O-GlcNAc antibody. RESULTS: The median IHC scores of O-GlcNAc or OGT between OSCC and normal tissues were not different, whereas those of phosphorylated-EGFRtyr1173 and phosphorylated-Aktser473 were significantly higher in OSCC than normal tissues (P < .001 and P < .01, respectively). Similarly, expression of O-GlcNAcylated proteins in oral cancer cells and normal oral keratinocytes did not differ. In the OSCC group, the median IHC scores of O-GlcNAc and OGT were significantly lower than those of phosphorylated-EGFRtyr1173 and phosphorylated-Aktser473 (P < .01 and P < .001, respectively). The IHC scores of O-GlcNAc or OGT were not determined to correlate with histological grading. CONCLUSION: Unlike other types of cancers, our findings demonstrate that the levels of O-GlcNAcylation are not significantly increased in OSCC tissues or in oral cancer cells and are not associated with the histological grading of OSCC.

Inhibitory effect of Thai propolis on human osteoclastogenesis.

BACKGROUND/AIM: Avulsed teeth should be immediately replanted into the socket or otherwise kept in a physiologic storage medium to maintain periodontal ligament cell viability. A previous study has demonstrated that Thai propolis extract can maintain viability of human periodontal ligament cells. However, root resorption by osteoclasts often occurs when the avulsed teeth are replanted. The aim of this study was to determine the inhibitory effect of Thai propolis extract on human osteoclastogenesis in vitro. MATERIALS AND METHODS: Human peripheral blood mononuclear cells were isolated for osteoclast precursors and cultured in the presence or absence of various non-toxic concentrations of propolis extract, as determined by the alamarBlue® assay, during in vitro induction of osteoclastogenesis. Osteoclast formation was examined by tartrate-resistant acid phosphatase staining, actin ring formation, and real-time polymerase chain reaction. The resorption pit assay was performed to determine osteoclast function. RESULTS: Non-toxic concentrations of propolis extract suppressed osteoclast formation by significantly decreasing the percentages of tartrate-resistant acid phosphatase-positive multinuclear cells and the ratios of cells with F-actin ring formation (P < .01) in a dose-dependent fashion. Expression of several osteoclast-specific genes was significantly downregulated by propolis in a dose-dependent manner (P < .05). The percentages of resorption areas on dentin slices were significantly decreased by propolis (P < .05). CONCLUSIONS: Thai propolis can inhibit human osteoclast formation and function, which may be beneficial for prevention of root resorption following replantation of avulsed teeth.

TFAP2B mutation and dental anomalies.

Mutations inTFAP2B has been reported in patients with isolated patent ductus arteriosus (PDA) and Char syndrome. We performed mutation analysis of TFAP2B in 43 patients with isolated PDA, 7 patients with PDA with other congenital heart defects and 286 patients with isolated tooth agenesis with or without other dental anomalies. The heterozygous c.1006G>A mutation was identified in 20 individuals. Those mutation carriers consisted of 1 patient with term PDA (1/43), 16 patients with isolated tooth agenesis with or without other dental anomalies (16/286; 5.6%), 1 patient with PDA and severe valvular aortic stenosis and tooth agenesis (1/4) and 2 normal controls (2/100; 1%). The mutation is predicted to cause an amino-acid substitution p.Val336Ile in the TFAP2B protein. Tfap2b expression during early mouse tooth development supports the association of TFAP2B mutation and dental anomalies. It is hypothesized that this incidence might have been the result of founder effect. Here we report for the first time that TFAP2B mutation is associated with tooth agenesis, microdontia, supernumerary tooth and root maldevelopment. In addition, we also found that TFAP2B mutations, the common causes of PDA in Caucasian, are not the common cause of PDA in Thai population.

The preservative effect of Thai propolis extract on the viability of human periodontal ligament cells.

BACKGROUND/AIM: Tooth avulsion causes an injury to the periodontal ligament (PDL). The success of tooth replantation depends on the quantity and quality of PDL cells. The aim of this study was to examine the preservative and proliferative effects of Thai propolis extract, previously shown to exert anti-inflammatory and antioxidant activities, on human PDL cells. MATERIALS AND METHODS: Ninety-six premolars were left to air dry for 30 min and stored in Hank's balanced salt solution (HBSS), milk, or various concentrations of propolis extract from 0.25 to 10 mg ml-1 for 3 h. PDL cells were isolated by collagenase and trypsin digestion, and their viability was determined by a trypan blue dye exclusion assay. PDL tissues were also scraped off the root surface and cultured to determine cell growth and morphology. The alamarBlue® and BrdU assays were performed to determine the cytotoxic and proliferative effects of the extract on cultured PDL cells, respectively. RESULTS: A non-toxic dose of 2.5 mg ml-1 of propolis extract yielded the greatest percentage of cell viability (78.84 ± 3.34%), which was significantly higher than those of the other concentrations (P < 0.001). Nevertheless, this percentage was not significantly different from that of HBSS (80.14 ± 2.44%; P = 1.00), but was significantly higher than that of milk (71.27 ± 2.79%; P < 0.001). The cells grown from PDL explants looked like fibroblasts. However, 2.5 mg ml-1 of the extract did not induce PDL cell proliferation. CONCLUSION: Thai propolis extract at 2.5 mg ml-1 appears to be the most effective dose for preserving the viability of PDL cells, and this was comparable to HBSS.

Enhancement of salivary human neutrophil peptide 1-3 levels by probiotic supplementation.

BACKGROUND: Probiotic supplementation can reduce mutans streptococci (MS) numbers. One of its proposed mechanisms is immunomodulation. Salivary human neutrophil peptide 1-3 (HNP1-3) levels have previously been demonstrated to be higher in caries-free than in caries-susceptible children, suggesting their preventive role against caries. We aimed to compare salivary HNP1-3 levels between an intervention group with probiotics and a control group. METHODS: A randomized double-blinded clinical trial was conducted. Sixty schoolchildren were equally allocated to either an intervention or control group. The use of a probiotic strain, Lactobacillus paracasei SD1, has shown to reduce MS numbers in volunteers. In unstimulated whole saliva, HNP1-3 levels were assayed by ELISA, and MS and lactobacilli counts were assayed by colony counting at baseline (T0) and at 3 (T3), 6 (T6), and 12 months (T12). The International Caries Detection and Assessment system was used to assess caries status. RESULTS: In the intervention group, salivary HNP1-3 levels were significantly greater than those in the control group at T3 and T6 (p < 0.001), whereas MS counts were significantly decreased (p < 0.01). In the intervention group, positive and negative correlations were found between HNP1-3 levels and lactobacilli counts and between MS and lactobacilli counts, respectively. However, there was no significant correlation between enhanced HNP1-3 levels and decreased MS numbers. The caries increment for the pit and fissure surface, but not for the smooth surfaces, was significantly decreased in the intervention group compared with the control group (p = 0.01). CONCLUSIONS: Probiotics can temporarily enhance salivary HNP1-3 levels; however, their action to reduce new pit and fissure caries probably involves microbial interactions. TRIAL REGISTRATION: TCTR20130904001 (registration date: September 04, 2013).

Positive correlations between hCAP18/LL-37 and chondroitin sulphate levels in chronic periodontitis.

AIM: To measure the levels of hCAP18/LL-37 in gingival crevicular fluid from patients with periodontal diseases compared with healthy controls and to determine the correlation between hCAP18/LL-37 and chondroitin sulphate (CS) levels in patients with periodontitis. MATERIAL AND METHODS: Gingival crevicular fluid samples from 51 patients and 25 healthy volunteers were analysed for the hCAP18/LL-37 levels by immunoblotting and were determined for the CS levels by the competitive enzyme-linked immunosorbent assay. RESULTS: Tris buffer pH 9.85 was selected to recover hCAP18/LL-37 from Periopaper strips, in which the percentages of recovery were around 70%. The median levels of hCAP18/LL-37 in the aggressive and the chronic periodontitis (CP) groups were significantly greater than those in the gingivitis and the healthy groups (p < 0.05). Significant correlations between the unprocessed 18-kDa fragment and CS levels (r = 0.650; p < 0.001) and between the mature 4.6-kDa fragment and CS levels (r = 0.502; p < 0.001) were observed only in the CP group. CONCLUSION: The significant correlations between the hCAP18/LL-37 and the CS levels were found in CP, but not in aggressive periodontitis. The presence versus absence of such correlations may be clinically applicable to help clinicians distinguish between two distinct types of periodontitis.

Favorable interleukin-8 induction in human gingival epithelial cells by the antimicrobial peptide LL-37.

BACKGROUND: LL-37, the only member of the antimicrobial peptide cathelicidin family in humans, exerts a variety of biological activities, especially immunomodulation through either direct chemotactic activity or up-regulation of several cytokines and chemokines in various cell types. In this study, we aimed to determine the immunoregulatory effect of LL-37 on Th1/Th2 cytokine expression and production in human gingival epithelial cells (HGECs). METHODS: Cultured HGECs were treated with different concentrations of LL-37 for different numbers of times. The cytotoxicity of LL-37 was determined by an MTT assay. Total RNA was isolated for RT-PCR and real-time PCR analyses of cytokine expression. Cell-free culture supernatants were assayed for Th1/Th2 cytokine levels by a cytokine bead array. RESULTS: Out of eleven Th1/Th2 cytokines tested, treatment of HGECs with non-toxic doses of LL-37 (2-6 µM) significantly raised only IL-8 levels in the cell-free culture supernatants, when compared to control untreated cells (P <0.05). Consistent with the elevated IL-8 levels, IL-8 mRNA expression was remarkably and significantly induced by LL-37 treatment (P < 0.05), when compared to the modest mRNA induction of other three cytokines, including IL-1ß, IL-6, and TNF-α. The time-course study demonstrated a cumulative IL-8 mRNA induction by LL-37 treatment within a 24-hour interval. CONCLUSIONS: These findings indicate that LL-37 favorably induces IL-8 expression and secretion in HGECs, suggesting both direct and indirect involvement of LL-37 in neutrophil recruitment into an inflammatory site within diseased periodontal tissues.

Comparisons between two biochemical markers in evaluating periodontal disease severity: a cross-sectional study.

BACKGROUND: The purpose of this study was to compare two biochemical markers, which have been previously used to determine the degrees of alveolar bone destruction, in evaluating periodontal disease severity. METHODS: The WF6 epitope of chondroitin sulfate (CS) and the alkaline phosphatase (ALP) levels were determined in gingival crevicular fluid (GCF) samples collected from patients with various degrees of disease severity, including ten patients with gingivitis (50 gingivitis sites) and 33 patients with chronic periodontitis (including gingivitis, slight, moderate, and severe periodontitis sites; n = 50 each), as well as from ten healthy volunteers (50 healthy sites) by Periopaper strips. The levels of CS and ALP were measured by an ELISA and a fluorometric assay, respectively. RESULTS: The results demonstrated low levels of CS and ALP in non-destructive and slightly destructive periodontitis sites, whereas significantly high levels of these two biomolecules were shown in moderately and severely destructive sites (p < 0.05). Although a significant difference in CS levels was found between moderate and severe periodontitis sites, no difference in ALP levels was found. Stronger correlations were found between CS levels and periodontal parameters, including probing depth, loss of clinical attachment levels, gingival index and plaque index, than between ALP levels and these parameters. CONCLUSIONS: It is suggested that the CS level is a better diagnostic marker than the ALP level for evaluating distinct severity of chronic periodontitis.

Synergistic Inhibition of Synbiotic Cultures among Lactobacilli and Plant Extracts against Vaginal Discharge Causing Candida albicans.

Vulvovaginal candidiasis (VVC) is the most common cause of vaginal discharge among women. The present study aimed to investigate the synergistic anticandidal effect of lactobacillus cultures supplemented with plant extracts. Among 600 isolates of lactic acid bacteria, 41 isolates exhibited inhibitory activity against Candida albicans ATCC10231. Six out of 41 cell-free supernatants demonstrated the most potent antibacterial and anticandidal activities. They also inhibited the clinical isolates of C. albicans, causing VVC and non-C. albicans. The synergistic effect between Lactobacillus crispatus 84/7 and Limosilactobacillus reuteri 89/4 was demonstrated by the lowest fractional inhibitory concentration index (FICI = 0.5). The synbiotic culture of bacterial combination, cultured with Jerusalem artichoke (H. tuberosus) extract, also exhibited the strongest inhibition against the tested C. albicans. Biofilm formation decreased after 12 h of incubation in the selected cell-free supernatants of this synbiotic culture. The anticandidal activity of crude extracts was lost after treatment with proteinase K and trypsin but not with heating conditions, suggesting that it may be a heat-stable substance. In conclusion, the combination of L. crispatus 84/7 and L. reuteri 89/4 with H. tuberosus may be a promising candidate for inhibiting Candida infection and biofilm formation, with the potential use as ingredients in vaginal biotherapeutic products.

Inhibition of P-glycoprotein mediated multidrug resistance by stemofoline derivatives.

Resistance to chemotherapy in cancer patients has been correlated to the overexpression of the ATP-binding cassette (ABC) drug transporters including P-glycoprotein (P-gp) that actively efflux chemotherapeutic drugs from cancer cells. We examined the multidrug resistance reversing property of stemofoline derivatives in drug-resistance human cervical carcinoma (KB-V1) and human leukemic (K562/Adr) cell lines that overexpress P-gp. Didehydrostemofoline and eleven of its derivatives were synthesized and the cytotoxicity and their effect on doxorubicin, vinblastine and paclitaxel sensitivity in drug resistant (KB-V1 and K562/Adr) and drug sensitive (KB-3-1 and K562) cell lines by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were determined. We found that three out of the twelve stemofoline derivatives including OH-A1, NH-B6 and NH-D6 showed commitment efficiency to increase sensitivity to doxorubicin, vinblastine and paclitaxel in KB-V1 cells and increase sensitivity to doxorubicin, and paclitaxel in K562/Adr cells whereas the effects have not been seen in their parental sensitive cancer cell lines (KB-3-1 and K562). These results indicate that stemofoline derivatives reversed P-gp-mediated multidrug resistance in vitro, and thus could be developed as effective chemosensitizers to treat multidrug-resistant cancers. The molecular mechanism of modulation of P-gp would be further determined.

Fluoride Release and Rechargeability of Poly(lactic acid) Composites with Glass Ionomer Cement.

This study investigates the fluoride release, rechargeability and degradation behaviors of newly developed anticariogenic poly(lactic acid) (PLA) composites. The PLA composite with various concentrations (0%, 5%, 10%, 15% and 20% by weight) of glass ionomer cement (GIC) and sodium fluoride (NaF) were prepared using solvent casting method. The fluoride release, fluoride rechargeability and degradation behavior were evaluated. All experimental groups demonstrated fluoride-releasing ability. The highest level of fluoride ions released was found in PLA composite with sodium fluoride (PLA/NaF). Following the 28-day period, both groups showed a gradual reduction in fluoride ion released, ranging between 0.03 ± 0.01 and 0.53 ± 0.06 ppm, although remaining within the effective range for tooth remineralization. However, the rechargeability was only observed in PLA composite with GIC (PLA/GIC). Following an eight-week in vitro degradation test, all PLA/NaF groups displayed a significantly higher percentage of weight change and water absorption compared to the PLA/GIC and the control group. In SEM analysis, the formation of surface porosities was clearly noticed in all PLA/NaF. All specimens retained their structural integrity throughout the study. In conclusion, the newly developed PLA/GIC displays promising possibilities as an anticariogenic material. Furthermore, the rechargeability of these ions are repeatable, ensuring their long-term utility.

The Bond Strength of Root Canal Filling after Calcium Hydroxide Removal with a Simple Apical Negative Pressure Kit in Oval-Shaped Root Canal.

Background: The aim of this study was to evaluate the effect of a simple irrigating device, which produced from the apical negative pressure concept, as a final irrigating method after calcium hydroxide (CH) medication on the bond strength of epoxy resin-based sealer in the oval-shaped root canal. Methods: Forty-eight single-rooted premolars with oval-shaped canals were included in the study. The crown was decoronized and canal instrumented with Mtwo (VDW GmbH, Munich, Germany) up to size 40/04. The specimens were assigned to four groups according to the irrigation protocol after 1 week of CH medication: control group (no medication) and three experimental groups conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), and simple apical negative pressure kit (sANP). The teeth were obturated with a warm vertical technique using epoxy resin-based sealers. After 1 week, the roots were transversally sectioned at coronal, middle, and apical thirds. A push-out test was performed by a universal testing machine, and statistical analysis was performed using One-Way ANOVA with Duncan's post hoc test. Results: The bond strength in the control group was significantly higher than the CNI group in all root canal thirds (P < 0.05). At coronal third, sANP showed lower bond strength than PUI group (P < 0.05). However, the bond strength of sANP group was comparable to the control group (P > 0.05) which was significantly higher than the PUI group at apical third (P < 0.05). Conclusion: A sANP enhanced the bond strength of epoxy resin-based sealer in the apical third of CH-medicated root canal in the oval-shaped canal.

Effect of surface topography and wettability on shear bond strength of Y-TZP ceramic.

Zirconia ceramics have been widely used as dental restorations due to their esthetic appearance and high flexural strength. The bonding of zirconia with resin cement should rely on both mechanical and chemical bonds. This study was performed to investigate the effect of zirconia surface topography and its wettability after surface pretreatments on the microshear bond strength (µSBS) of a resin cement. Zirconia slabs were prepared and randomly divided into 5 groups based on the surface treatment as follows: no treatment (control), air abrasion (AB), etching with hydrofluoric acid (F), the mixture of hydrofluoric acid and nitric acid (FN), or the mixture of hydrochloric acid and nitric acid (CN) for 10 min. The specimens were subjected to investigation of surface roughness characteristics [average roughness (Ra), peak-to-valley average distance (Rpv), skewness (Rsk), and kurtosis (Rku)] using atomic force microscopy (AFM) and measurements of surface contact angle (θc) and µSBS of a resin cement. In addition, the area % of the nanoscale surface irregularity (nSI%) was calculated from the AFM images. The effects of nSI%, Ra and θc on the µSBS were analyzed by multiple linear regression analysis (p < 0.05). Multiple regression analysis revealed that the nSI% was the most predominant factor for the µSBS (p < 0.001). A surface with larger nSI%, higher Ra and relatively lower θc was essential for establishing a reliable resin-zirconia bond.