Antibacterial effectiveness of photo-sonodynamic treatment by methylene blue-incorporated poly(D, L-lactide-co-glycolide) acid nanoparticles to disinfect root canals.

AIM: This in-vitro investigation aimed to assess the antibacterial effectiveness of photo-sonodynamic treatment using methylene blue (MTB)-incorporated poly(D, L-Lactide-Co-Glycolide) acid (PLGA)-nanoparticles for the disinfection of root canals. METHODS: The synthesis of PLGA nanoparticles was achieved using a solvent displacement technique. The morphological and spectral characterization of the formulated PLGA nanoparticles were carried out using scanning electron microscopy (SEM) and Transformed-Fourier infrared spectroscopy (TFIR), respectively. One hundred human premolar teeth were sterilized and then their root canals were infected with Enterococcus faecalis (E. faecalis). Later, the bacterial viability evaluation of the following 5 research groups was conducted: (a) G-1: specimens treated with a diode laser; (b) G-2: specimens treated with antimicrobial photodynamic therapy (aPDT) and 50 µg/mL of MTB-incorporated PLGA nanoparticles; (c) G-3: specimens treated with ultrasound (US); (d) G-4: specimens treated with US and 50 µg/mL of MTB-incorporated PLGA nanoparticles; and (e) G-5: control group consisting of specimens that did not undergo any treatment. RESULTS: Under SEM, the nanoparticles exhibited a uniform spherical shape and were around 100 nm. The formulated nanoparticles' size was validated through zeta potential analysis utilizing dynamic light scattering (DLS). The TFIR images of both PLGA nanoparticles and MTB-incorporated PLGA nanoparticles exhibited absorption bands ranging from around 1000 to 1200/cm and nearly from 1500 to 1750/cm. The G-5 samples (control group) demonstrated the greatest viability against E. faecalis, followed by G-3 (US-conditions specimens), G-1 (diode laser-conditioned specimens), G-2 (aPDT + MTB-incorporated PLGA-nanoparticles-conditioned specimens), and G-5 (US + MTB-incorporated PLGA-nanoparticles-conditioned specimens). Significant statistical differences (p < 0.05) were observed among all research groups, including both the experimental groups and control group. CONCLUSION: The combination of US via MTB-incorporated PLGA nanoparticles exhibited the most effective eradication of E. faecalis, suggestive of a promising therapeutic modality against E. faecalis for disinfecting root canals with complex and challenging anatomy.

The adhesive strength of fiber post-to-canal dentin with Aniline green, Fotoenticine activated by PDT, green tea, and ozone as a final irrigant.

AIM: The effect of novel final disinfection protocols Malachite green (MG), Fotoenticine® (FTC), Green tea extract (GTE), and Ozonated water (OW) on the bond strength of prefabricated glass fiber posts (PGFP) adhered to canal dentin. MATERIAL AND METHOD: The canals of fifty premolars with closed apices were cleansed and obturated. The specimens were randomly assigned to one of five groups based on the final irrigant used, with the control group receiving NaOCl+EDTA and the experimental groups receiving MG, FTC, OW, and GTE. The GFP was cemented with a self-etching, dual-cure paste; the bond strength was estimated with a universal testing machine; and failure analysis was conducted with a stereomicroscope. RESULTS: The highest PBS was observed in the coronal third of Group 4 (using ozonated water as the final irrigant), whereas the lowest bond integrity was observed in the apical section of Group 2 (1.02-0.54 MPa) using Malachite green as the final irrigant. Group 1, Group 4, and Group 5 exhibited no significant difference in the bond integrity of GFP to dentin when compared to Group 2 (p>0.05). In addition, comparable bond score values were obtained for Groups 2 and 3 (p>0.05). CONCLUSION: The results of this study suggest that OW and GTE may be effective final disinfectants for root canals, as they increase the bond strength of resin-luting cement.

Coffee Staining and Simulated Brushing Induced Color Changes and Surface Roughness of 3D-Printed Orthodontic Retainer Material.

This in vitro study evaluated the influence of combined coffee staining and simulated brushing-induced color changes and surface roughness on 3D-printed orthodontic retainers. Specimens measuring 10 × 10 × 0.75 mm3 were obtained either by conventional vacuum forming or 3D printing at four print angulations (0°, 15°, 30°, and 45°) (n = 10). The prepared specimens were immersed in a coffee beverage and then mechanically brushed using a simulating device. The specimen's color difference (ΔE) and surface roughness (Ra) were quantified using a spectrophotometer and a non-contact profilometer, respectively. The highest and lowest mean ΔE values were recorded for the 3D-printed-45° (4.68 ± 2.07) and conventional (2.18 ± 0.87) groups, respectively. The overall mean comparison of ΔE between the conventional and 3D-printed groups was statistically significant (p < 0.01). After simulated brushing, all groups showed a statistically significant increase in the Ra values (p < 0.01). The highest Ra was in the 3D-printed-45° (1.009 ± 0.13 µm) and conventional (0.743 ± 0.12 µm) groups, respectively. The overall ΔE of 3D-printed orthodontic retainers was not comparable to conventional VFRs. Among the different angulations used to print the retainers, 15° angulations were the most efficient in terms of color changes and surface roughness and were comparable to conventional VFRs.

Efficacy of antimicrobial photodynamic therapy versus antiviral therapy in the treatment of herpetic gingivostomatitis among children: Aa randomized controlled clinical trial.

AIM: The aim of the present study was to evaluate the effect of antimicrobial photodynamic therapy (aPDT) as an adjunctive treatment to topical antiviral therapy for the treatment of children having herpetic gingivostomatitis. MATERIALS AND METHODS: 45 individuals (age group 12-18 years) with herpetic gingivostomatitis (HG) were divided into three groups on the basis of provision of treatment. (a) Group A: topical anti-viral therapy (TAT) (n = 14, mean age = 17.0 years) (b) Group B: antimicrobial photodynamic therapy (aPDT) (n = 15, mean age =17.7 years) and (c) Group C: topical anti-viral therapy + adjunctive aPDT (n = 16, mean age = 18.0 years) respectively. Pain scores [visual analogue scale (VAS) and McGill Pain Questionnaire (MPQ)] were assessed and HSV-1 was quantified. ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA) was used to compute the pro-inflammatory cytokine including interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α). The analysis of the mean values and inter group comparisons were evaluated with the Mann-Whitney test. The Friedman test was used to establish the comparison of the changes observed in HSV quantification, pain scores, and pro-inflammatory cytokines. ANOVA tests were employed for the quantification of differences observed at follow-ups. The assessments for the clinical trial were done at baseline, immediate after post-op, two, and four weeks, and three and six months respectively. RESULTS: According to the analysis of the data obtained after the clinical assessment, the three groups reported a decrease in the pain scores, HSV-1 quantification and levels of the pro-inflammatory cytokines. However, Group C (TAT + aPDT) reported improvement in the observed parameters which was statistically significant in comparison to Group A (TAT) and Group B (aPDT) respectively. CONCLUSION: Antimicrobial photodynamic therapy (aPDT) in conjunction with topical antiviral therapy (TAT) helped in reducing the pain scores and pro-inflammatory cytokine levels in herpetic gingivostomatitis among children.

Topographical changes and bactericidal efficacy of antimicrobial photodynamic therapy on titanium implant surface.

BACKGROUND: reExtensive rsearch has been done on various disinfection modalities used to achieve an aseptic implant surface. However, the bacterial efficacy and the topographical alterations resulting from the use of these techniques have never been compared. OBJECTIVE: This study aimed to evaluate and compare the disinfection efficacy and surface changes on a bacteria contaminated titanium block following application of various disinfectants. METHOD: Ultrasonically cleaned titanium blocks were contaminated with Porphyromonas gingivalis and Tannerella forsythia. The infected titanium implants were randomly divided into four experimental groups and decontaminated using antimicrobial photodynamic therapy (aPDT), laser therapy, chlorhexidine and hydrogen peroxide. Bacterial viability and surface changes following decontamination were analyzed. RESULT: Bacterial viability decreased in all the groups, with aPDT having the highest reduction. Surface roughness remained unchanged whereas the contact angle lessened in the aPDT group. CONCLUSION: aPDT could possibly be a suitable alternative to other disinfection regimen to treat periimplantitis.

The effect of heat treatment and surface neutralization on bond strength of orthodontic brackets to lithium disilicate glass-ceramic.

PURPOSE: The study evaluated and compared the effect of pre-etching heat treatment and post-etching surface neutralization on the surface texture parameters and initial adhesion strength of orthodontic brackets bonded to lithium disilicate glass-ceramic using water-based and resin-based cement. MATERIALS AND METHODS: A total of 120 samples were fabricated by duplicating the buccal surface of the maxillary premolar. The samples were randomly assigned to two groups: the cementing surface of group 1 samples was heat-treated, and that of group 2 samples was left untreated. The samples of each group were further divided into 4 subgroups (n = 15) according to the use of neutralization and the type of cement used for bonding. The surface texture parameters after etching were determined using a non-contact surface profilometer, and the bond strength was determined by a universal material tester. The results were analyzed by analysis of variance and the Scheffe post hoc test. RESULTS: The samples that were heat-treated showed statistically significant higher bond strength in all the subgroups, and the acid-neutralized samples showed higher bond strength using both types of cement; however, the increase was statistically significant only in resin-based cement-bonded samples. Resin-based cement-bonded samples showed higher bond strength than water-based cement-bonded samples. CONCLUSION: Pre-etching heat treatment and post-etching acid neutralization of the cementing surface of lithium disilicate glass-ceramic significantly improve the surface texture and initial bond strength to orthodontic brackets.

Dual-curing resin cement with colour indicator for adhesively cemented restorations to dental tissues: Change of colour by curing and some physical properties.

The study was aimed to investigate a color indicator containing dual curing resin composite luting cement and to plot the color change to the time of solidification of the cement. In addition some physical properties were studied. Specimens were made of a dual-cure resin cement (Maxcem Elite™ Chroma, Kerr, Orange, CA, USA) and polymerized by autopolymerization only, or with light initiated polymerization. A spectrophotometer was used to quantify the color change of the cement as plotted with the curing time. The efficacy of the curing process was studied by measuring water sorption and the ultimate flexural properties of the cement. The results showed that the flexural strength of cement after autopolymerization was 27.3 MPa and after light initiated polymerization 48.1 MPa. Young's modulus of bending was 2089.3 MPa and 3781.5 MPa respectively for the same cement samples. Water sorption after two weeks for the autopolymerization cement samples was -1.12 wt% and for the light initiated polymerization samples 0.56 wt%. Non-parametric Spearman's correlation was measured for autopolymerized cement samples between variables for color and solidification load (N), which showed a strong correlation between curing process and color change (p < 0.05). There was a correlation between the color change and degree of monomer conversion of the dual curing resin composite luting cement which contained a color indicator system for polymerization reaction. The study also suggested that autopolymerization only resulted in suboptimal polymerization of the cement. By additional light curing considerably higher flexural properties were obtained.

Effect of two-step and one-step surface conditioning of glass ceramic on adhesion strength of orthodontic bracket and effect of thermo-cycling on adhesion strength.

PURPOSE: The adhesion strength of orthodontic brackets bonded to dental glass ceramics was evaluated after ceramic surface was treated with two-step and one-step surface conditioning systems, and subjecting to thermo-cycling. MATERIALS AND METHOD: A total of forty specimens were fabricated from silica based glass ceramic (lithium disilicate) by duplicating the buccal surface of maxillary first premolar. The specimens were randomly assigned to two experimental groups (n = 20), group one specimens were treated with two-step surface conditioning system (IPS ceramic etching gel™ and Monobond plus™) and group two specimens were treated with one-step surface conditioning system (Monobond etch and prime™). The surface roughness of the specimens after treatment with two-step and one-step surface conditioning system was measured using non-contact surface profilometer. Ten randomly selected specimens from each group were subjected to thermo-cycling and the remaining ten served as baseline. The shear bond strength of the specimens was measured using universal material testing machine. The adhesive remnant index score was calculated, and the results of surface roughness and bond strength were tabulated and subjected to analysis of variance and post hoc tukey's test at a significance level of p < 0.05. RESULTS: The results of the study showed that the specimens treated with two-step conditioning system had higher surface roughness and bond strength than one-step conditioning system. The majority of the specimens treated with both two-step and one-step conditioned specimens showed adhesive failure after subjecting thermo-cycling. CONCLUSIONS: Traditional two-step conditioning provides better bond strength. The clinical importance of the study is that, the silane promoted adhesion significantly reduces on exposure to thermo-cycling.

Effects of stress rate and calculation method on subcritical crack growth parameters deduced from constant stress-rate flexural testing.

OBJECTIVES: To more efficiently determine the subcritical crack growth (SCG) parameters of dental ceramics, the effects of stressing rate and choice of statistical regression model on estimates of SCG parameters were assessed. METHODS: Two dental ceramic materials, a veneering material having a single critical flaw population (S) and a framework material having partially concurrent flaw populations (PC), were analyzed using constant stress-rate testing, or "dynamic fatigue", with a variety of testing protocols. For each material, 150 rectangular beam specimens were prepared and tested in four-point flexure according to ISO6872 and ASTM1368. A full-factorial study was conducted on the following factors: material, stress rate assumed vs. calculated, number of stress rates, and statistical regression method. RESULTS: The proportion of specimens for which the statistical models over-estimated reliability was not significantly different based on regression method for Material S (P = 0.96, power = 94%) and was significantly different based on regression method for Material PC (P < 0.001). The standard method resulted in SCG parameters, n and l nB, of 35.9 and -11.1 MPa(2)s for Material S and 12.4 and 9.61 MPa(2)s for Material PC, respectively. SIGNIFICANCE: The method of calculation that uses only the median strength value at each stress rate provided the most robust SCG parameter estimates. Using only two stress rates resulted in fatigue parameters comparable to those estimated using four stress rates having the same range. The stress rate of each specimen can be assumed to be the target stress rate with negligible difference in SCG parameter estimates.