Effects of prostaglandin E2 on clonogenicity,proliferation and expression of pluripotent markers in human periodontal ligament cells

Background and objectiveBased on our earlier work on the response of periodontal ligament (PDL) cells to mechanical stress by induction of cyclooxygenase expression and production of prostaglandin PGE₂ that could regulate mineralization of PDL cells, it was hypothesized that PGE₂ had potential effects on PDL stemness. In this study, we aimed to investigate clonogenicity, proliferation and expression of certain pluripotent markers, considered to be characteristics of PDL stemness, in response to treatment with exogenously-added PGE₂.Material and methodsHuman PDL cells were cultured and treated with various doses of PGE₂, and the aforementioned characteristics of PDL stemness were analyzed.ResultsThe clonogenicity and proliferation were significantly enhanced by PGE₂ at low concentrations (0.01, 0.1 and 1 ng/ml; P < 0.05), but only the proliferation was significantly diminished by PGE₂ at a high concentration (100 ng/ml; P < 0.05). Expression of NANOG and OCT4 mRNA and protein was increased by PGE₂ treatment at 0.1 and 1 ng/ml. Consistently, expression of stage-specific embryonic antigen 4, a putative stem cell marker, was significantly augmented by PGE₂ treatment at 1 ng/ml (P < 0.05).ConclusionOur findings suggest that although a high dose of PGE₂ (100 ng/ml) inhibits proliferation of PDL cells, PGE₂ at low doses appears to play a role in the maintenance of PDL stemness.     

Effects of autogenous growth factors on heterotopic bone formation of osteogenic cells in small animal model

AimsThis study used a new approach to investigate the effective concentrations of growth factors released from platelet concentrate (PC) on the bone formation capacity of osteogenically differentiated rat bone marrow stromal cells (rBMSCs).Materials and methodsRat BMSCs and whole blood were harvested from 40 adult male Spraque-Dawly rats. Rat BMSCs were expanded in an osteogenic medium and seeded on inert collagenous bovine bone matrix (ICBM). Growth factors released from degranulated PC (GFs) containing TGF-β1 1 (25 ng/ml)–10 ng (250 ng/ml) and rhBMP-2 400 ng (10 μg/ml) were suspended in 40 μl platelet poor plasma (PPP) and applied on the ICBM–rBMSC constructs or ICBM only, respectively. The constructs were then transplanted in autologous hosts for 4 weeks. Concurrently, osteoblastic differentiation of rBMSCs on ICBM–rBMSC–PPP constructs was characterized in vitro.ResultsRat BMSCs in osteogenic medium exhibited phenotypes of mature osteoblasts. The amount of newly formed bone among groups of ICBM–rBMSC–PPP with and without GFs was not significantly different (p > 0.05) and was significantly lower than a group of ICBM–PPP–BMP-2 (p < 0.05).ConclusionsAutogenous GFs had no effect on the capacity of rBMSCs to form new bone. The ability to measure the bone formation capacity of transplanted autologous cells and growth factors in a small animal model was demonstrated.     

The effect of omega-3 in temporomandibular joint synovial tissues of rats with induced arthritis: pilot study

This study evaluated the effect of systemic administration of omega-3 on the expression of interleukins IL-1β and IL-10 and tumour necrosis factor alpha (TNF-α) and on the thickness of cartilage in the temporomandibular joint (TMJ) inflammatory model induced by complete Freund’s adjuvant (CFA). Thirty-two adult rats were divided equally into four groups: control, CFA (induced arthritis), and induced arthritis animals treated with dexamethasone or omega-3. The TMJs were then removed and assigned to histomorphometric analysis or immunoassay. The Kruskal–Wallis test with Dunn post hoc test was applied to the data; the significance level was set at 5%. IL-1β levels (median; interquartile range) were higher (P < 0.0001) in the CFA group (46.4 ng/ml; 39.4–53.3) than in the control group (1.81 ng/ml; 1.5–5.4), but there were no differences between the control, omega-3, and dexamethasone groups. TNF-α levels were also higher (P < 0.0001) in the CFA group (122.7 ng/ml; 92.9–284.7) than in the control group (29.1 ng/ml; 23.7–31.3). IL-10 levels were lowest (P < 0.0001) in the CFA group (73.5 ng/ml; 52.8–90.5), and no differences were found amongst the other groups. In conclusion, omega-3 successfully reduced the damage in the TMJ of induced arthritis rats. Further investigations are warranted to confirm whether the administration of omega-3 has a comparable effect to glucocorticoids in rheumatoid arthritis patients.     

Water sorption and solubility of core build-up materials

ObjectivesTo investigate the variation in water sorption and solubility across a range of different core build-up materials.MethodsFive materials were tested, four of which are resin-based materials (Grandio Core, Core.X Flow, Bright Flow Core, Speedee) and one resin-modified glass ionomer (Fuji II LC). All specimens (n = 10) were immersed in 10 ml distilled water in individual glass containers and weighed at one week, 14 and 28 days. After a total immersion time of 28 days, 7 specimens were dried to a constant mass, in a desiccator for 28 days. Three samples of each material were not dried, but were left in distilled water for 1 year, to determine the long-term water sorption properties. Specimens were weighed at monthly intervals until 6 months and then at the 9th and 12th months. Each specimen was measured using a digital electronic caliper (Mitutoyo Corporation, Japan).ResultsAfter 28 days immersion, the change in water sorption and solubility of the materials ranged from 12.9 to 67.1 μg/mm³ (P < 0.001) and 0.9–6.4 μg/mm³ respectively (P < 0.001). Except for Fuji II LC, an independent T-test showed significantly higher water sorption and solubility for the other materials after 1-year total immersion in water compared to 1 month (P < 0.05). Using repeated measures ANOVA, all materials showed mass changes over time (1 month) (P < 0.001).SignificanceGrandio Core had the lowest water sorption and solubility among the tested materials. According to the ISO 4049 standards, all the tested materials showed acceptable water sorption and solubility, apart from the water sorption behavior of Fuji II LC.     

Irrigation fluid volume requirement for conventional arthrocentesis of the temporomandibular joint: a cadaver study

Temporomandibular joint (TMJ) arthrocentesis is considered an effective and minimally invasive procedure for certain conditions related to temporomandibular disorders. The ideal irrigation volume for arthrocentesis lavage has not yet been defined. Therefore, the aim of this study was to evaluate the efficacy of different saline solution volumes in removing methylene blue from the TMJ space of fresh human cadavers. Nineteen cadavers were selected and 1 ml of 10 μM methylene blue solution was injected into the upper joint space unilaterally. Conventional arthrocentesis was then conducted by infusion of 300 ml of 0.9% saline solution, collecting a 1-ml sample from the drained quantity for every 25 ml injected. Finally, the samples were assayed by measuring photo absorbance of the methylene blue solution. There was a statistically significant difference between the irrigation volumes regarding the removal of methylene blue solution from the joint space (P < 0.001), specifically between the first 25 ml and 200 ml (P = 0.014), 225 ml (P = 0.001), 250 ml (P < 0.001), and 275 ml (P = 0.001). Based on this ex vivo study, a 25-ml perfusion volume appears to be sufficient for joint lavage in conventional arthrocentesis of the TMJ.     

Stability of bonds made to superficial vs. deep dentin,before and after thermocycling

ObjectivesBonding stability of resinous adhesives to dentin is still problematic and may involve regional variations in dentin composition. This study is to evaluate the effect of dentin depth on the stability of resin-dentin bonds under thermocycling challenge.MethodsDentin slabs with two flat surfaces parallel to the tooth axis were obtained from extracted human third molars. The slabs were randomized into eight groups according to the location of dentin [deep dentin (DD) or superficial dentin (SD)], the adhesive treatment (Single Bond 2 or Clearfil S³ Bond), and the storage treatment (thermocycling for 5000 times vs. no). After the adhesive treatment and composite buildup on the dentin slabs, the micro-shear bond strength (μSBS) of each group was detected. The concentrations of cross-linked carboxyterminal telopeptide of type I collagen (ICTP) were also evaluated using an immunoassay to detect the degree of collagen degradation in each group.ResultsDentin depth, adhesive treatment and storage treatment all showed significant effects on both the μSBSs and the ICTP values (P < 0.05). Regardless of the adhesive type, thermocycling decreased the μSBSs and increased the ICTP values (P < 0.05). The DD groups showed significantly lower μSBSs and higher ICTP values than SD groups after thermocycling aging (P < 0.05). The treatment with Single Bond 2 significantly increased the ICTP values (P < 0.05), whereas Clearfil S³ Bond showed no effect on the ICTP values (P > 0.05).SignificanceDeep dentin showed significantly more bond degradation after thermocycling than did superficial dentin.     

In vitro dentine remineralization with a potential salivary phosphoprotein homologue

ObjectiveAdvantages of introducing a salivary phosphoprotein homologue under standardized in vitro conditions to simulate the mineral-stabilizing properties of saliva have been proposed. This study longitudinally investigates the effects of casein, incorporated as a potential salivary phosphoprotein homologue in artificial saliva (AS) solutions with/without fluoride (F) on in vitro dentine lesion remineralization.DesignThin sections of bovine root dentine were demineralized and allocated randomly into 6 groups (n = 18) having equivalent mineral loss (ΔZ) after transverse microradiography (TMR). The specimens were remineralized using AS solutions containing casein 0 μg/ml, F 0 ppm (C₀–F₀); casein 0 μg/ml, F 1 ppm (C₀–F₁); casein 10 μg/ml, F 0 ppm (C₁₀–F₀); casein 10 μg/ml, F 1 ppm (C₁₀–F₁); casein 100 μg/ml, F 0 ppm (C₁₀₀–F₀) or casein 100 μg/ml, F 1 ppm (C₁₀₀–F₁) for 28 days with TMR taken every 7 days.ResultsSurface mineral precipitation, evident in group C₀–F_1, was apparently inhibited in groups with casein incorporation. Repeated measures ANOVA with Bonferroni correction revealed higher ΔZ for non-F and non-casein groups than for their counterparts (p < 0.001). Subsequent multiple comparisons showed that mineral gain was higher (p < 0.001) with 10 μg/ml casein than with 100 μg/ml when F was present in the earlier stages of remineralization, with both groups achieving almost complete remineralization after 28 days.ConclusionCasein is a potential salivary phosphoprotein homologue that could be employed for in vitro dentine remineralization studies. Concentration related effects may be clinically significant and thus must be further examined.     

Jaw-stretch reflex is weaker in patients after orthognathic surgery

ObjectivesThe jaw-stretch reflex (JSR) was studied in both patients and healthy participants in order to investigate the possible long-term impact of orthognathic surgery on the motor function of the masticatory system.DesignJSR was measured in patients before surgery (PC), 1 year after surgery (PS) and in healthy controls (HC) (N = 31 in each group). JSR was evoked by a standardized stretch device and recorded bilaterally from masseter and anterior temporalis muscles using surface electromyography (EMG).ResultsThe peak-to-peak amplitude (which was normalized to pre-stimulus EMG activity) of JSRs in PC and PS were significantly smaller than in HC (P < 0.001; P < 0.001). The onset latency in PS was significantly longer compared with HC (P < 0.05). The duration of JSR in PS was significantly longer than in HC and PC (P < 0.001; P < 0.05).ConclusionPatients with dentofacial deformities are characterized by reduced JSR amplitude. The delayed onset and elongated duration of JSR might be potential indicators of a long-term surgical impact on the motor function of the masticatory system.     

Hydrogen peroxide induces cell proliferation and apoptosis in pulp of rats after dental bleaching in vivo: Effects of the dental bleaching in pulp

ObjectiveThis study provides an in vivo evaluation of the inflammatory response, levels of cell proliferation and apoptosis, and the presence of necrosis after dental bleaching with two concentrations of hydrogen peroxide (H₂O₂).DesignWistar rats were divided into Control (placebo gel), BLUE (20% H₂O₂, 1 × 50 min), and MAXX (35% H₂O₂, 3 × 15 min) groups. At 2 and 30 days, the rats were killed (n = 10). The jaws were processed for histology analysis and PCNA and Caspase-3-cleaved immunohistochemistry, and data were submitted to the Mann-Whitney or ANOVA test (P < 0.05).ResultsAt 2 days, the MAXX group showed necrosis and the BLUE group revealed moderate inflammation on the occlusal third of the crown (P < 0.05). At 30 days, tertiary dentin had formed and there was an absence of inflammation. The level of cell proliferation was higher in the middle third of the BLUE group (P < 0.05), and cervical of MAXX at 2 days (P < 0.05), decreasing at 30 days. The apoptosis was present at 2 days, particularly in the cervical third of the crown in the bleached groups (P < 0.05), with a decrease only at 30 days in the BLUE group (P < 0.05).ConclusionsThe concentration of H₂O₂ influences effects on the pulp tissue, where a higher concentration of H₂O₂ can cause necrosis in the pulp and a prolonged effect within the apoptotic process; lower concentrations of H₂O₂ provide moderate inflammation, cell proliferation and apoptosis with a reduction of these processes over time.     

Evaluation of effects of activator treatment on mandibular growth by analyzing components of condylar growth and mandibular rotation

PurposeThe objective of this study is to clarify the effects of activator treatment on mandibular growth in relation to condylar growth and total rotation of the mandible, and to investigate the relationships between the treatment responses and pretreatment facial morphology.Materials and methodsThirty Japanese girls with Class II division 1 malocclusion treated with activator were examined. Mean age at the start of treatment was 9.6 ± 1.6 years. Mean treatment duration was 19 ± 4 months. Lateral cephalograms obtained before and after treatment were used to analyze skeletal changes during treatment. Regional superimposition analysis was performed to evaluate activator effects by decomposing the mandibular growth into condylar growth and mandibular total rotation.ResultsThe changes in intermaxillary relationships were significantly correlated with vertical condylar growth and mandibular total rotation (P < 0.05 and P < 0.01). The changes in the forward displacement of the mandible were significantly correlated with sagittal condylar growth and mandibular total rotation (P < 0.05 and P < 0.01). Vertical condylar growth and mandibular total rotation were significantly correlated with pretreatment mandibular morphology (P < 0.05 and P < 0.01).ConclusionBoth the sagittal condylar growth and counterclockwise mandibular total rotation attributed to activator treatment contribute to forward displacement of the mandible. The activator effects are expected greater in patients with flat mandibular plane, small gonial angle, backwardly inclined mandibular ramus and long posterior facial height.     

Human neutrophil peptide-1 affects matrix metalloproteinase-2, -8 and -9 secretions of oral squamous cell carcinoma cell lines in vitro

ObjectivesThe present study aimed to investigate the effect of HNP-1 on the matrix metalloproteinase (MMP)-2, -8 and -9 secretions of two oral squamous cell carcinoma (OSCC) cell lines (UT-SCC-43A and UT-SCC-43B).DesignIn all experiments, the two OSCC cell lines were incubated with graded concentrations (0, 1, 5, and 10 μg/ml) of HNP-1 for 24 and 48 h. Cell viability was measured using a colorimetric proliferation test and cell death was analyzed with a colorimetric cytotoxicity detection kit. Enzyme activity of MMP-2 and MMP-9 was detected by using gelatin zymography, and molecular weight forms of MMP-8 were determined by Western-blot and a densitometric quantitation method.ResultsBoth cell lines showed a significant increase in LDH toxicity at 24 h (UT-SCC-43A: p = 0.005 & UT-SCC-43B: p = 0.014). Reduced gelatinolytic activities of proMMP-2 were detected in UT-SCC-43B cell line after 24 and 48 h of incubation with HNP-1 (1 μg/ml: p < 0.001, 5 μg/ml: p < 0.001, and 10 μg/ml: p = 0.0225). MMP-8 levels of both cell lines decreased at 200–250 kDa after 24 h of incubation, while after 48 h only UT-SCC-43B decreased at 45–50 kDa.ConclusionsOur results indicate that HNP-1 suppresses the secretion of MMP-2, -8, and -9 in OSCC cell lines.     

Effects of risedronate on osteoblastic cell cultures

ObjectiveBisphosphonates (BPs) have been widely used in the treatment of bone disorders due to their ability to modulate bone turnover. The biological mechanisms through BFs exert their effects on osteoclasts are well established. However, the role of BFs on the osteoblasts is controversial. The present study aimed to evaluate the effects of risedronate on osteoblastic cells.DesignMC3TE-E1 cells were exposed to risedronate at 0, 10⁻⁸, 10⁻⁶, 10⁻⁴, and 10⁻³ M. The following parameters were assayed: (1) cell proliferation by hemocytometer counting after 24, 48 and 72 h, (2) cell viability by MTT assay after 24, 48 and 72 h, (3) Type I Collagen quantification by ELISA after 24, 48 and 72 h, (3) alkaline phosphatase activity after 7 and 10 days and (4) matrix mineralization after 14 days.ResultsAfter 24 h, risedronate did not affect both cell proliferation and viability (p > 0.05). However, after 48 and 72 h, a decrease in cell proliferation and viability was detected in osteoblastic cultures exposed to risedronate at 10⁻⁴ and 10⁻³ M (p < 0.05). After 48 and 72 h, Type I Collagen synthesis was stimulated by risedronate at 10⁻⁴ M (p < 0.05). High levels of ALP activity were detected in cultures exposed to risedronate at 10⁻⁴ M after 7 and 10 days (p < 0.05). After 14 day, high calcium content was observed in cultures exposed to risedronate at 10⁻⁴ M (p > 0.05).ConclusionThese results indicated that risedronate can promote osteoblast differentiation.     

Novel fluoride rechargeable dental composites containing MgAl and CaAl layered double hydroxide (LDH)

ObjectiveThis study aims to incorporate 2:1 MgAl and 2:1 CaAl layered double hydroxides (LDHs) in experimental dental-composites to render them fluoride rechargeable. The effect of LDH on fluoride absorption and release, and their physico-mechanical properties are investigated.Methods2:1 CaAl and 2:1 MgAl LDH-composite discs prepared with 0, 10 and 30 wt% LDH were charged with fluoride (48 h) and transferred to deionized water (DW)/artificial saliva (AS). Fluoride release/re-release was measured every 24 h (ion-selective electrodes) with DW/AS replaced daily, and samples re-charged (5 min) with fluoride every 2 days. Five absorption-release cycles were conducted over 10 days. CaAl and MgAl LDH rod-shaped specimens (dry and hydrated; 0, 10 and 30 wt%) were studied for flexural strength and modulus. CaAl and MgAl LDH-composite discs (0, 10, 30 and 45 wt% LDH) were prepared to study water uptake (over 7 weeks), water desorption (3 weeks), diffusion coefficients, solubility and cation release (ICP-OES).ResultsCaAl LDH and MgAl LDH-composites significantly increased the amount of fluoride released in both media (P < 0.05). In AS, the mean release after every recharge was greater for MgAl LDH-composites compared to CaAl LDH-composites (P < 0.05). After every recharge, the fluoride release was greater than the previous release cycle (P < 0.05) for all LDH-composites. Physico-mechanical properties of the LDH-composites demonstrated similar values to those reported in literature. The solubility and cation release showed a linear increase with LDH loading.SignificanceLDH-composites repeatedly absorbed/released fluoride and maintained desired physico-mechanical properties. A sustained low-level fluoride release with LDH-composites could lead to a potential breakthrough in preventing early stage carious-lesions.     

Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes

ObjectivesNickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro.MethodsIn accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n = 6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1β) and additionally stimulated with different Ni(II) concentrations (400 and 4000 ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control.ResultsOur experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p > 0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p < 0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p < 0.001), MMP expressions were in line with our findings (p < 0.001). The mRNA data were supported by proliferation and wound closure assays (p < 0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB.SignificanceOur in vitro study implicated that Ni(II) has various modifying effects on IL-1β-induced inflammatory processes depending on the concentration.     

Anti-inflammatory effect of an adhesive resin containing indomethacin-loaded nanocapsules

ObjectiveTo analyze the anti-inflammatory and analgesic effects of an adhesive resin containing indomethacin-loaded nanocapsules in rat model.DesignAdhesive resin disks with or without indomethacin-loaded nanocapsules were subcutaneously implanted into right hind paw of rats. A week after surgical procedure, 2% formalin solution was intradermally injected into plantar surface of paw. Nociceptive and inflammatory responses were evaluated by formalin test. Paw edema by pletismometer and mechanical hyperalgesia by von Frey test were performed on day 2, day 4, day 6, day 8, day 10 and day 12 after surgery. IL-6, IL-10, and lactate dehydrogenase (LDH) serum levels were determined by ELISA-sandwich test.ResultsGroup containing indomethacin-loaded nanocapsules (NC) presented lower edema in the right hind paw at 24 h after formalin injection than those of the control group (CT) (P < 0.01). NC group showed decrease in the nociceptive response in phase I (neurogenic pain) compared to CT group (NC − 66.86 ± 22.83 s X CT − 130.17 ± 35.83s , P < 0.001). NC group presented supporting higher intensity of stimulus on days 8 and 12 (24 h and 72 h after formalin injection) (P < 0.01 and P < 0.02 respectively). The IL-6 serum level was also significantly higher in the NC group than CT group (p < 0.001).ConclusionsThese results indicate that an adhesive resin containing indomethacin-loaded nanocapsules has anti-inflammatory and nociceptive activities in a chemical model of acute inflammation. The present investigation confirms an adhesive resin with drug-loaded nanocapsules may be useful for improving therapeutic effect for adhesives to be used in deep cavities.     

Efficacy of dexamethasone with controlled hypotension on intraoperative bleeding,postoperative oedema and ecchymosis in rhinoplasty

PurposeThe aim of this retrospective study was to evaluate the efficacy of dexamethasone with controlled hypotension on intraoperative bleeding and postoperative morbidity in rhinoplasty.Materials and methodsSixty rhinoplasty patients required hump resection and lateral osteotomy were included in this study. The patients were randomized into four groups. In group I (n = 15), a single dose of 10 mg/kg dexamethasone was intravenously administered at the beginning of the operation. In group II (n = 15), the patients were given 2 doses of 10 mg/kg intravenously dexamethasone at the beginning of the operation, and 24 hours after the operation. In group III (n = 15), 3 doses of 10 mg/kg intravenously dexamethasone were given at the beginning of the operation, before osteotomy and 24 hours after the operation. Group IV (n = 15) was assigned as control group and the patients were neither administered dexamethasone nor applied hypotension. All cases in groups I, II and III were operated under controlled hypotension. Systolic arterial pressure was aimed to keep between 65 and 75 mmHg for controlled hypotensive anaesthesia. Controlled hypotension was achieved by a remifentanil infusion of 0.1–0.5 microg/kg/min, following a bolus of 1 microg/kg. Degree of eyelid oedema and periorbital soft-tissue ecchymosis was evaluated separately using a scale of 0–4. Intraoperative blood loss was recorded for each patient. Patients were evaluated at 24 hours and postoperative days 2, 5, 7, and 10.ResultsIn groups I, II and III, intraoperative bleeding was more decreased and the operation time was significantly shorter compared with control group (P < 0.001). Eyelid oedema and periorbital ecchymosis were significantly decreased in groups I, II and III at the following postoperative 7 and 10 days (P < 0.001). There was statistically significant difference between group III and other groups at the postoperative 5 and 7 days in lower eyelid oedema (P < 0.001), upper and lower eyelid ecchymosis (P < 0.001 and 0.004, respectively). There were no postoperative complications with using steroid in any of the groups.ConclusionThree doses of dexamethasone with controlled hypotension considerably reduced postoperative morbidities of rhinoplasty with osteotomy as well as intraoperative bleeding. Thus, in group III receiving 3 doses of steroid, when compared to other groups, more uneventful postoperative period were provided for surgeon and the patients.     

Effect of laser activated bleaching on the chemical stability and morphology of intracoronal dentin

ObjectivesTo evaluate the effect of the bleaching with 35% hydrogen peroxide either activated or not by a 970 nm diode laser on the chemical stability and dentin surface morphology of intracoronary dentin.MethodsTwenty-seven slabs of intracoronary dentin specimens (3 × 3 mm) were distributed into three groups (n = 9), according to surface treatment: HP – 35% hydrogen peroxide (1 × 4’), DL – 970 nm diode laser (1 × 30”/0,8W/10 Hz), HP + DL – 35% HP activated with 970 nm diode laser (1 × 30”/0,8W/10 Hz leaving the gel in contact to the surface for 4′ after activation). Three Raman spectra from each fragment were obtained to calculate the mean intensity of peaks of inorganic component (a.u.), organic collagen content (a.u.), and the ratio of inorganic/organic content, before and after treatment. Analyses of the samples by confocal laser microscopy were performed to evaluate the surface roughness, percentage of tubules, perimeter and area percentage of tubules, before and after treatment. Data were analyzed by Kruskal-Wallis, Dunn’s, and Wilcoxon test (P < 0.05).ResultsData analysis showed that HP + DL did not change the inorganic content peaks 8.31 [29.78] or the inorganic/organic ratio 3.37 [14.67] (P > 0.05). Similarly, DL did not affect the chemical stability of the dentin surface (P > 0.05). However, HP significantly increased inorganic content peaks 10.87 [22.62], as well as the inorganic/organic ratio 6.25 [27.78] (P < 0.05). Regarding the morphological alterations, all surface treatments increase tubules exposure; HP treatment significantly increases perimeter and area percentage; and HP + DL increases surface roughness.ConclusionsBleaching HP combined with DL offers an improvement in terms of intracoronal dentin surface protection, yielding better maintenance of dentin chemical stability and morphology.     

The efficacy of Salvadora persica extract in the elimination of the intracanal smear layer: A SEM study

AimTo evaluate the efficacy of an ethanolic Salvadora persica extract in removing the smear layer following a root canal procedure.MethodsSixty extracted, single-rooted human teeth were cleaned, shaped, and divided into four groups. Experimental groups 1 (n = 20) and 2 (n = 20) were irrigated with 1 mg/ml and 5 mg/ml of S. persica, respectively. The positive controls (n = 10) were irrigated with 17% ethylenediaminetetraacetic acid (EDTA), while the negative controls (n = 10) were irrigated with saline. Approximately 5 ml of the irrigating solution was delivered into the root canals for 5 min, and the final rinse was performed with 5 ml of 1% sodium hypochlorite. Scanning electron microscopy was used to evaluate the endodontic smear layer removal at the coronal, middle, and apical thirds of the specimens.ResultsA significant difference in smear layer removal between groups 1 and 2 at the coronal and middle thirds of the canal was observed, and no significant difference was seen between group 2 and the positive control at the coronal third. At the apical third, both concentrations of S. persica had similar effects and were less effective than the positive control in removing the smear layer.ConclusionThe 5 mg/ml S. persica solution was significantly more effective than the 1 mg/ml solution. In addition, the 5 mg/ml S. persica solution was as effective as 17% EDTA in removing the smear layer from the coronal third of the canal wall.     

Camouflage treatment in skeletal Class III cases combined with severe crowding by extraction of four premolars

PurposeTo evaluate the changes in dentoskeletal structures and profile after extraction of four premolars in adult skeletal Class III borderline cases.Subjects and methodsThirteen Chinese patients (mean age was 22.0 ± 4.5 years) with skeletal Class III malocclusions and severe crowding in the upper arch were included in the study. These cases were diagnosed to be in the borderline surgical-orthodontic range but refused surgical treatments. All of them were treated by extraction of four premolars and standard edgewise technique. Lateral cephalometric radiographs taken at the start and end of treatment were analysed. Twenty-six cephalometric variables were calculated and paired t-tests were performed to assess the statistical significance of the treatment effects.ResultsNo significant changes were noted in the skeletal parameters (P ≥ 0.05). Regarding the dental parameters, the L1-MP angle decreased by 8.4°, the U1-L1 angle increased by 11.7° (P < 0.01), the L1-NB angle decreased by 10.1° and the L1-NB distance decreased by 5.2 mm (P < 0.01). The soft tissue parameters of Li-E, Li-H and Li-RL2 distance decreased by 3.3 mm, 3.3 mm and 4.5 mm, respectively (P < 0.01). All the patients finished with favorable occlusion and a straight profile.ConclusionsThe orthodontic camouflage by extraction of four premolars provides a viable treatment alternative for borderline skeletal Class III cases to achieve satisfying occlusal relationship and improve facial esthetics.     

Chloride channels regulate chondrogenesis in chicken mandibular mesenchymal cells

Voltage gated chloride channels (ClCs) play an important role in the regulation of intracellular pH and cell volume homeostasis. Mutations of these genes result in genetic diseases with abnormal bone deformation and body size, indicating that ClCs may have a role in chondrogenesis. In the present study, we isolated chicken mandibular mesenchymal cells (CMMC) from Hamburg–Hamilton (HH) stage 26 chick embryos and induced chondrocyte maturation by using ascorbic acid and β-glycerophosphate (AA-BGP). We also determined the effect of the chloride channel inhibitor NPPB [5-nitro-2-(3-phenylpropylamino) benzoic acid] on regulation of growth, differentiation, and gene expression in these cells using MTT and real-time PCR assays. We found that CLCN1 and CLCN3–7 mRNA were expressed in CMMC and NPPB reduced expression of CLCN3, CLCN5, and CLCN7 mRNA in these cells. At the same time, NPPB inhibited the growth of the CMMC, but had no effect on the mRNA level of cyclin D1 and cyclin E (P > 0.05) with/without AA-BGP treatment. AA-BGP increased markers for early chondrocyte differentiation including type II collagen, aggrecan (P < 0.01) and Sox9 (P < 0.05), whilst had no effect on the late chondrocyte differentiation marker type X collagen. NPPB antagonized AA-BGP-induced expression of type II collagen and aggrecan (P < 0.05). Furthermore, NPPB downregulated type X collagen (P < 0.05) with/without AA-BGP treatment. We conclude that abundant chloride channel genes in CMMC play important roles in regulating chondrocyte proliferation and differentiation. Type X collagen might function as a target of chloride channel inhibitors during the differentiation process.