Resin modified glass ionomer bonded to caries affected dentin disinfected with carbon dioxide laser, diode lasers, bee glue and photosensitizing agents: An estimation of bond strength.

AIM: The present in vitro study was carried out to evaluate the effect of different cavity disinfectants chlorhexidine (CHX), riboflavin (RF), diode laser (DL), carbon dioxide laser (CO2), and Propolis on the bond values of resin-modified glass ionomer cement (RMGIC) restoration bonded to caries affected dentin (CAD) MATERIALS AND METHODS: Forty multi-rooted mandibular molars were adapted in self-cure acrylic resin blocks up to the level of the cementoenamel junction so that only the crown portion of the tooth remained visible. Silicon carbide discs of 1200 and 600 grits were then used to remove infected dentin. However, CAD was left behind to use as a substrate for restoration. All samples were randomly divided into five groups based on the method of disinfection. group 1: Propolis, group 2: CHX, group 3:RF activated by PDT, group 4: CO2 laser, and group 5: DL. RMGIC restoration was then placed on these disinfected samples. Samples were kept in an incubator keeping humidity at 100 % and temperature at 37 °C for about 24 hrs. All samples were then placed in a Universal testing machine to measure SBS. Failure modes were identified using a stereomicroscope. ANOVA test was used to analyze intergroup comparison. Tukey HSD test was used to evaluate multiple group comparisons. The level of significance was set at a p < 0.05 value. RESULTS: Group 2 specimens disinfected with CHX established the highest SBS value (17.85±1.09 MPa). Whereas, Group 5 specimens in which CAD was disinfected with DL demonstrated the lowest SBS (10.36±0.33MPa). CONCLUSION: CO2 has the potential to be used as an alternate to CHX for caries-eaffected dentin disinfection. However, Riboflavin activated by photodynamic therapy; Diode laser, and Propolis as cavity disinfectant prior bond to resin-modified glass ionomer is not recommended and needs further probing.

Interfacial Adhesion of a Semi-Interpenetrating Polymer Network-Based Fiber-Reinforced Composite with a High and Low-Gradient Poly(methyl methacrylate) Resin Surface.

The research aimed to determine the tensile bond strength (TBS) between polymerized intact and ground fiber-reinforced composite (FRC) surfaces. FRC prepregs (a reinforcing fiber pre-impregnated with a semi-interpenetrating polymer network (semi-IPN) resin system; everStick C&B) were divided into two groups: intact FRCs (with a highly PMMA-enriched surface) and ground FRCs (with a low PMMA gradient). Each FRC group was treated with: StickRESIN and G-Multi PRIMER. These groups were further divided into four subgroups based on the application time of the treatment agents: 0.5, 1, 2, and 5 min. Next, a resin luting cement was applied to the FRC substrates on the top of the photo-polymerized treating agent. Thereafter, weight loss, surface microhardness, and TBS were evaluated. Three-factor analysis of variance (p ≤ 0.05) revealed significant differences in the TBS among the FRC groups. The highest TBS was recorded for the intact FRC surface treated with G-Multi PRIMER for 2 min (13.0 ± 1.2 MPa). The monomers and solvents of G-Multi PRIMER showed a time-dependent relationship between treatment time and TBS. They could diffuse into the FRC surface that has a higher PMMA gradient, further resulting in a high TBS between the FRC and resin luting cement.

Bond assessment of resin modified glass ionomer cement to dentin conditioned with photosensitizers, laser and conventional regimes.

AIM: To assess different conditioning regimes on shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC) bonded to dentin MATERIAL AND METHODS: Fifty non carious intact maxillary molars were cleaned, isolated and randomly divided into five groups (n = 10). Before randomization, dentin surface was exposed and finished. Samples in group 1 were conditioned with methylene blue photosensitizer (MBP) 50 mg/l and activated by photodynamic therapy (PDT), Group 2: surface treated with Er,Cr:YSGG (ECL), Group 3: surface conditioned with polyacrylic acid (PAA) (control), Group 4: surface conditioned with 17 % Ethylenediaminetetraacetic acid (EDTA), Group 5: surface conditioned with total etch (Optibond solo Plus). For SBS testing the samples were placed in universal testing machine. Fracture analysis of debonded surfaces were evaluated using stereomicroscope at 40x magnification. Means and standard deviations were calculated using analysis of variance (ANOVA) and Tukey's post hoc test at a significance level of (p < 0.05). RESULTS: The maximum bond strength was found in group 5 conditioned with Optibond solo plus total etch (23.15 ±â€¯3.21 MPa). Whereas, the lowest bond values were observed in group 1 treated with MBP (15.25 ±â€¯1.54 MPa). Moreover, samples in group 2, group 3 and group 4 resulted in comparable bond strength (p > 0.05). CONCLUSION: MBP at 50 mg/l is not recommended to condition dentin prior to RMGIC application. Moreover, ECL has a potential to be suggested for dentin conditioning compared to PAA.

Clinical, host-derived immune biomarkers and microbiological outcomes with adjunctive photochemotherapy compared with local antimicrobial therapy in the treatment of peri-implantitis in cigarette smokers.

AIM: The aim of this study was designed to assess the peri-implant oral hygiene parameters, clinical, radiographic, host-derived immune biomarkers and microbiological levels after photochemotherapy (PCT) and local antibiotic therapy (LAT) in peri-implantitis lesions among cigarette smokers. MATERIALS AND METHODS: Fifty current cigarette smokers with peri-implantitis were divided into two groups: PCT and LAT. Test implants received PCT that consisted of toluidine blue photosensitizer and application of 660 nm diode laser with a total of 100 mW power and 124.3 W/cm2 energy using continuous mode of irrigation for 60 s. Control implants received one-unit subgingival application of metronidazole gel in viscous consistency. Clinical measurements included the assessment of plaque scores (PS), bleeding on probing (BOP), probing depth (PD) and clinical attachment level (CAL). Intraoral standardized digital peri-apical radiographs were taken at baseline and at 12 months. Interleukin (IL)-1ß and matrix metalloproteinase (MMP)-1 in the PICF were determined using the manufacturers guide from one-step enzyme-linked immunosorbent assay. Real-time polymerase chain reaction (PCR) for Parvimonas micra, Porphyromonas gingivalis and Tannerella forsythia was performed and counts evaluated at baseline, 3, 6 and 12-months. RESULTS: Plaque scores reduced in both groups (p < 0.05). Mean BOP percentage significantly increased in both the groups at 1-month follow-up compared to baseline. Following this period, BOP showed reduction from 1-month to consecutive follow-up periods. The PD significantly reduced in both the groups with no statistically significant difference when compared between PCT and LAT groups at follow-up (p > 0.05). CAL did not change over the period and between both groups (p > 0.05). The differences from baseline to 12 months and between the groups for mesial and distal crestal bone levels did not show any statistical significance (p > 0.05). The levels of IL-1ß significantly dropped from baseline to 12 months in the LAT group (p < 0.05). However, for PCT groups, the levels of IL-1ß significantly reduced only at 12-month visit follow-up (p < 0.05). MMP-1 showed statistically significant reduction at 9 and 12-months compared with baseline for LAT group. Both P. gingivalis and T. forsythia showed statistically significant reduction in both the groups when values were compared from baseline to 3-, 6- and 12-months follow-up (p < 0.05). However, these differences were not significant when compared between the groups (p > 0.05). CONCLUSION: Both PCT and LAT showed equal efficacies in improving clinical, host-derived immune biomarkers and microbiological parameters in peri-implant infection in cigarette smokers.

Repeated application of photodynamic and antibiotic therapy as an adjunct to root surface debridement in patients with grade C and stage III or IV aggressive periodontitis.

PURPOSE: To evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) and antimicrobial therapy on clinical and immunological outcomes of periodontal treatment in patients with periodontitis grade C and stage III or IV. MATERIAL AND METHOD: The patients recruited in the current research fulfil the clinical case definition of periodontitis 'grade C' in terms of onset of the infection and stage III or IV that defines degree and severity of the disease. One-stage full-mouth ultrasonic debridement (UD) was performed and randomly divided in two groups: Group-I - four applications of aPDT, and Group-II - combination of metronidazole (MTZ) and amoxicillin (AMX) 3 tablets each for 7 days. Whole-mouth periodontal parameters were recorded at baseline, 3-, 6-months after completion of treatment. Gingival crevicular fluid samples were obtained for assessment of inflammatory interleukin (IL)-10 and IL-17 at the same time points. RESULTS: Seventeen healthy patients completed the study protocol and revealed similar clinical findings at baseline. Bleeding scores significantly reduced in group-I at 3 months post treatment (p < 0.05). It could be seen that group-I showed statistically significant reduction of deep periodontal pockets and gain in CAL in patients with GAP at 3 months (p < 0.05). This difference was maintained at 6 months of follow-up (p < 0.001). Group-II was capable of increasing the levels of IL-10 and reducing IL-17 in GCF at both time periods compared to Group-I (p < 0.05). Group-I did not have significant effect on either cytokine levels in GCF (p > 0.05). CONCLUSION: Antimicrobial photodynamic therapy improved severe deep periodontal pockets. However, the combination of antimicrobial therapy helped in reducing proinflammation in grade C and stage III or IV periodontitis.

Characterization of osteogenic cells grown over modified graphene-oxide-biostable polymers.

Graphene is an excellent filler for the development of reinforced composites. This study evaluated bone cement composites of graphene oxide (GO) and poly(methyl methacrylate) (PMMA) based on the proliferation of human bone marrow mesenchymal stem cells (hBMSCs), and the anabolic and catabolic effects of the incorporation of GO on osteoblast cells at a genetic level. Surface wettability and roughness were also evaluated at different GO concentrations (GO1: 0.024 wt% and GO2: 0.048 wt%) in the polymer matrix. Fabricated specimens were tested to (a) observe cell proliferation and (b) identify the effectiveness of GO on the expression of bone morphogenic proteins. Early osteogenesis was observed based on the activity of alkaline phosphatase and the genetic expression of the run-related transcription factor 2. Moreover, bone strengthening was determined by examining the collagen type 1 alpha-1 gene. The surface roughness of the substrate material increased following the addition of GO fillers to the resin matrix. It was found that over a period of ten days, the proliferation of hBMSCs on GO2 was significantly higher compared to the control and GO1. Additionally, quantitative colorimetric mineralization of the extracellular matrix revealed greater calcium phosphate deposition by osteoblasts in GO2. Furthermore, alizarin red staining analysis at day 14 identified the presence of mineralization in the form of dark pigmentation in the central region of GO2. The modified GO-PMMA composite seems to be promising as a bone cement type for the enhancement of the biological activity of bone tissue.