A protocol for an overview of systematic reviews to map photodynamic inactivation evidence in different dental specialties.

This is a protocol for an overview to summarize the findings of Systematic Reviews (SR) dealing with Photodynamic Inactivation (PDI) for control of oral diseases. Specific variables of oral infectious will be considered as outcomes, according to dental specialty. Cochrane Database of Systematic Reviews (CDSR), MEDLINE, LILACS, Embase, and Epistemonikos will be searched, as well as reference lists. A search strategy was developed for each database using only terms related to the intervention (PDI) aiming to maximize sensitivity. After checking for duplicate entries, selection of reviews will be performed in a two-stage technique: two authors will independently screening titles and abstracts, and then full texts will be assessed for inclusion/exclusion criteria. Any disagreement will be resolved through discussion and/or consultation with a third reviewer. Data will be extracted following the recommendations in Chapter V of Cochrane Handbook and using an electronic pre-specified form. The evaluation of the methodological quality and risk of bias (RoB) of the SR included will be carried out using the AMSTAR 2 and ROBIS. Narrative summaries of relevant results from the individual SR will be carried out and displayed in tables and figures. A specific summary will focus on PDI parameters and study designs, such as the type and concentration of photosensitizer, pre-irradiation time, irradiation dosimetry, and infection or microbiological models, to identify the PDI protocols with clinical potential. We will summarize the quantitative results of the SRs narratively.

Effect of polishing and bleaching on color, whiteness, and translucency of CAD/CAM monolithic materials.

OBJECTIVE: To evaluate the effect of polishing and bleaching on the recovery of lightness, color, whiteness, and relative translucency parameter (RTP) in CAD/CAM materials and changes in these properties when another staining in coffee was conducted after the treatments. MATERIALS AND METHODS: Disks of Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were (1) not treated (control), (2) polished with Proxyt or (3) Ceramisté, (4) bleached with Opalescence PF or (5) Whiteness HP Blue, and (6) air polished with Clinpro Prophy Powder. CIE L*a*b* color coordinates were registered at baseline (R0), after staining with coffee for 30 min daily for 36.5 days and treatment (R1), and after another staining (R2). Differences (R1-R0 and R2-R0) in lightness (ΔL00), color (ΔE00), RTP (ΔRTP00), and whiteness (ΔWID) were evaluated by mixed repeated measures ANOVA and 95% confidence intervals (α = 0.05) and interpreted in function of their respective 50:50% PT and AT thresholds. Topography was evaluated by scanning electron microscopy (SEM). RESULTS: In LU, Opalescence PF and Proxyt decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {\mathrm{R}}_0\right)} $$ , and ΔWI D R 1 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$ and showed lower Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ . In VE, all treatments decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , and ΔWI D R 1 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$ , whereas Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ were lower in Opalescence PF than in the control group. In both moments, ΔE00 and ΔWID in EMP (also ΔL00) and EMAX were higher in Opalescence PF than in the control group, from which the other treatments did not differ in R1-R0. In EMP, Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ in Whiteness HP Blue (also Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ ) and Proxyt were also higher in comparison to the control group and in VS, Ceramisté decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , and Δ R T P 00 R 1 - R 0 $$ \varDelta RT{P}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , whereas Opalescence PF increased ΔRTP 00 R 1 - R 0 $$ {\Delta \mathrm{RTP}}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ . Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Ceramisté and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ and Δ R T P 00 R 2 - R 0 $$ \varDelta RT{P}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Proxyt were lower than those of the control group. CONCLUSIONS: The most suitable treatment to recover the lightness, color, whiteness, and RTP without changing these properties after another coffee exposure is material-dependent. CLINICAL SIGNIFICANCE: Although the effectiveness of the treatment was material-dependent, Proxyt was the only treatment that promoted clinically acceptable changes for both LU and VE, while for purely ceramic materials, this condition was observed with Ceramisté and Clinpro Prophy Powder.

Long-term effect of gastric juice alternating with brushing on the surface roughness, topography, and staining susceptibility of CAD-CAM monolithic materials.

STATEMENT OF PROBLEM: Studies on the behavior of computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic materials subjected to gastric juice alternating with brushing-as occurs in patients with bulimia nervosa-are lacking. PURPOSE: The purpose of this in vitro study was to evaluate, over a simulated 5-year period, the effect of gastric juice alternating with brushing on the roughness, topography, and staining susceptibility of CAD-CAM monolithic materials. MATERIAL AND METHODS: Disks of Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were randomly allocated to artificial saliva+brushing or gastric juice+brushing groups, simulating 1, 3, and 5 years of clinical function. The roughness (Sa) and topography were evaluated at baseline (T0) and at each simulated year. For the staining susceptibility (ΔE00), the CIELab color coordinates were registered at baseline, and, at the end of the fifth simulated year, the specimens were immersed in deionized water, coffee, or cola before the second reading. Roughness data were submitted to mixed repeated-measures ANOVA and Bonferroni, and the staining susceptibility data were analyzed by 3-way ANOVA and the Games-Howell test (α=.05). RESULTS: The gastric juice+brushing led to higher roughness than artificial saliva+brushing only in the VE at T3 and T5 (P<.01). In both treatments, the LU and VE showed topography changes and an increase in roughness over time (P<.001), in addition to higher roughness than the other materials (P<.001). The staining susceptibility of the materials to each staining solution was not affected by the treatment (P>.05). The LU and VS groups were more stained by coffee (P<.001), while the VE and EMP groups were more stained by cola (P≤.016), except for the EMP in the gastric juice+brushing, where no significant difference was found between cola and coffee (P>.05). The EMAX was imperceptibly affected by the 3 solutions. CONCLUSIONS: Concerning roughness and topography, the LU and VE were the most affected by both treatments. The staining susceptibility of the materials was not affected by the treatment.

Development and assessment of an indirect vision training programme for operatory dentistry: Effects on working posture.

OBJECTIVES: Students experience difficulty working with indirect vision and often adopt inadequate working postures because of it. This study created and then assessed the effects of an indirect vision preclinical training programme on dental students' working posture. METHODS: The study enrolled students in the third year of the 5-year undergraduate programme in dentistry in the School of Dentistry of São Paulo State University (UNESP), Araraquara (N = 54). The programme consisted of four training sessions in which students performed different types of activities in which only a mirror was used to see the procedure they were performing. To evaluate posture, students were asked to perform class III cavity preparations (distal-palatal and mesial-palatal preparations) on upper central and lateral incisors in a dental mannequin (tooth numbers 11, 12, 21 and 22) both before and after the indirect vision training programme. Photographs were taken of the students' working postures. The photographs were assessed by a duly trained researcher using the Compliance Assessment of Dental Ergonomic Posture Requirements. A descriptive statistical analysis was performed, and the assumptions of normality were verified. Student's paired t test was also performed. The significance level adopted was 5%. RESULTS: A significant difference was found between the percentages of correct ergonomic postures adopted before and after the training programme (p = 0.039). CONCLUSIONS: The preclinical training programme for indirect vision was found to have a positive effect on the working postures of the students evaluated herein.

Does airborne-particle abrasion before, rather than after, zirconia sintering lead to higher mechanical strength even under aging challenge?

STATEMENT OF PROBLEM: Information concerning the effect of airborne-particle abrasion before zirconia sintering on its strength after aging is lacking. PURPOSE: The purpose of this in vitro study was to determine the influence of airborne-particle abrasion moment (before or after zirconia sintering), particle size, and aging on the mechanical strength of a yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic. MATERIAL AND METHODS: Four hundred presintered zirconia disks were allocated to nonabraded (control) and abraded groups with 50 µm or 120 µm Al2O3 particles before (50/BS or 120/BS) or after sintering (50/AS or 120/AS). The disks were aged by storing them in distilled water for 24 hours at 37 °C (24 h) (control); mechanical cycling (MC) (1×106 cycles; 2 Hz; 100 N); hydrothermal aging (HA) (134 °C; 0.2 MPa; 20 hours); or by both methods (MC+HA), totaling 20 groups (n=20). The specimens were subjected to biaxial flexural strength (BFS) testing. Fractographic analysis was performed to identify the fracture origin. Tetragonal to monoclinic transformation was determined by X-ray diffraction. The BFS data (MPa) were analyzed by 2-way ANOVA and the Games-Howell post hoc test (α=.05). Weibull statistics was also applied. RESULTS: The BFS and characteristic strength (σ0) of the 120/AS groups were significantly higher compared with the other abraded groups and statistically similar or higher compared with the respective nonabraded groups. In contrast, the 120/BS/24 h and all the 50/BS groups presented the lowest values. In all groups, the initial defect had its origin on the tensile stress side. Neither airborne-particle abrasion nor aging (except for the 50/AS/MC+HA) reduced the zirconia reliability compared with the respective controls. Abrading the zirconia in its presintered stage or after sintering increased the monoclinic phase content, and the sintering process eliminated this phase. CONCLUSIONS: Airborne-particle abrasion before zirconia sintering yields an inferior performance compared with that after sintering under aging challenges. The BFS and σ0 were strongly determined by the particle size and airborne-particle abrasion moment, while aging mainly acted in the nonabraded zirconia or when this material was abraded before sintering.

Implementing magnification during pre-clinical training: Effects on procedure quality and working posture.

OBJECTIVE: The objective of this study was to evaluate the effects of magnification on the quality of two pre-clinical procedures, class I cavity preparations and composite resin restorations, and to evaluate the working posture. METHODS: This was an experimental laboratory study. The response variables were the quality of cavity preparations and Class I restorations as well as the working posture adopted during the execution of these procedures. The independent variables were the magnification system under four levels (unaided visualisation, the use of a simple loupe, the use of a Galilean loupe and the use of a Keplerian loupe) and the artificial teeth treated. Class I cavity preparations and restorations (N = 320) were performed using standardised procedures, and the quality achieved was evaluated using pre-established criteria. Working posture was recorded using digital video cameras and was evaluated using the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). A two-factor analysis of variance (ANOVA) and multiple comparison test were performed (α = 0.05). RESULTS: The quality of cavity preparation did not differ significantly amongst the different magnification systems (P = 0.082). Galilean and Keplerian systems had a positive impact on restoration quality only for the left mandibular first molar (P = 0.04). Higher posture scores were observed when Galilean and Keplerian loupes (P = 0.01) were used, regardless of the tooth being treated. CONCLUSION: The use of Galilean and Keplerian magnification lenses did not affect the quality of the pre-clinical procedures performed whilst improved the scores of ergonomic posture.

The influence of Cisplatin-based chemotherapy on the osseointegration of dental implants: An in vivo mechanical and histometrical study.

OBJECTIVES: To evaluate the effect of Cisplatin on bone repair and mineralization around implants and on the mechanical properties of bone tissue. MATERIALS AND METHODS: Forty-three Wistar rats were randomly divided into two groups: Cisplatin (CIS, medication) and control (CTL, placebo solution), administered once a week for 4 weeks. After 4 weeks, implants were installed in both tibiae metaphysis. After 30 and 60 days, the animals were sacrificed and their femurs and tibiae were removed. Femurs were subjected to mechanical tests and tibiae for removal torque, arrangement and distribution of collagen fibers, morphometrical analyses (bone tissue in contact with the implant surface [BIC] and areal fraction between implant threads occupied by bone tissue [BAFO]) and scanning electron microscopy to calcium and calcium/phosphorus analysis. Data were analyzed by ANOVA or MANOVA, and Tukey or Games-Howell post hoc tests, respectively (α = 0.05). RESULTS: The CTL specimens had significantly higher values (0.0001 ≤ p≤0.036) of strength (N), removal torque (N/cm2 ), %BIC, and %BAFO than CIS specimens, being their best results at day 60. No significant differences were found among the groups regarding the values of deformation, percentage of calcium, and calcium/phosphorus ratio. In CIS groups, there was a reduction in the organization of collagen at the bone/implant interface, resulting in a trabecular bone with thin trabeculae and birefringent collagen and irregular arrangement. CONCLUSIONS AND CLINICAL IMPLICATIONS: Cisplatin interfered negatively in the repair and mineralization around dental implants, as well as on the quality of the bone tissue, mainly in the period of 30 days after the implant placement.

Curcumin-mediated anti-microbial photodynamic therapy against Candida dubliniensis biofilms.

The purpose of this study was to evaluate the effectiveness of anti-microbial photodynamic therapy (aPDT) mediated by curcumin (Cur) associated with LED light against biofilms of Candida dubliniensis, and further, investigate cellular uptake and drug penetration through the biofilms under confocal laser scanning microscopy (CLSM). Four C. dubliniensis strains were tested: three clinical isolates from HIV-positive patients and one reference strain (CBS 7987). Biofilms were treated with three Cur concentrations (20.0, 30.0, and 40.0 µM). All samples were incubated in the dark for 20 min and exposed to a 5.28 J/cm2 of LED light fluence. Additional samples of each strain were treated either with Cur or LED light only. Control samples had neither Cur nor light. After aPDT, results were read using the XTT salt reduction method. The data were statistically analyzed by two-way ANOVA followed by Games-Howell post-hoc test (α = 0.05). Confocal laser scanning microscopy was used to verify both the uptake of Cur by yeast cells and its penetration through the biofilm. The results showed that aPDT promoted significant reduction on the metabolism of the biofilm-organized cells of C. dubliniensis. Further, while Cur was rapidly taken up by C. dubliniensis cells, a longer time interval was required to allow Cur penetration into biofilm cells. Based on these results, aPDT associating LED and Cur presents promising potential on fungal control of biofilms of C. dubliniensis.

Polyethyleneimine and Chitosan Polymer-Based Mucoadhesive Liquid Crystalline Systems Intended for Buccal Drug Delivery.

The buccal mucosa is accessible, shows rapid repair, has an excellent blood supply, and shows the absence of the first-pass effect, which makes it a very attractive drug delivery route. However, this route has limitations, mainly due to the continuous secretion of saliva (0.5 to 2 L/day), which may lead to dilution, possible ingestion, and unintentional removal of the active drug. Nanotechnology-based drug delivery systems, such as liquid crystalline systems (LCSs), can increase drug permeation through the mucosa and thereby improve drug delivery. This study aimed at developing and characterizing the mechanical, rheological, and mucoadhesive properties of four liquid crystalline precursor systems (LCPSs) composed of four different aqueous phases (i) water (FW), (ii) chitosan (FC), (iii) polyethyleneimine (FP), or (iv) both polymers (FPC); oleic acid was used as the oil phase, and ethoxylated and propoxylated cetyl alcohol was used as the surfactant. Polarized light microscopy and small-angle X-ray scattering indicated that all LCPSs formed liquid crystalline states after incorporation of saliva. Rheological, texture, and mucoadhesive assays showed that FPC had the most suitable characteristics for buccal application. In vitro release study showed that FPC could act as a controlled drug delivery system. Finally, based on in vitro cytotoxicity data, FPC is a safe buccal drug delivery system for the treatment of several buccal diseases.

Reliability of the agar based method to assess the production of degradative enzymes in clinical isolates of Candida albicans.

The aim of this study was to establish a reproducible protocol using the methodology of hyaline zones around the colonies on specific agar plates for phospholipase and proteinase production. This was an in vitro double-blind experiment, in which the dependent variables were the enzymatic activity measurements (Pz) for the production of phospholipase (Pz-ph) and the production of secreted aspartyl proteinases (Pz-sap). Three independent variables give rise to different measurement protocols. All measurements were carried out at two different moments by four examiners (E1, E2, E3, and E4). The minimum sample size was 30 Candida albicans clinical isolates. Specific agar plates for phospholipase and SAPs production were prepared according the literature. The intra-and inter-examiner reproducibility for each protocol was estimated using the Intraclass Correlation Coefficient (ICC) and its confidence interval (95% CI). Based on the results obtained for both phospholipase and SAPs, there appears to be no consensus on the protocol chosen for each particular examiner. Measuring the colonies in triplicate may be the main factor associated with the increase in measurement accuracy and should therefore take precedence over measuring only one colony. When only one examiner is responsible for taking measurements, a standard protocol should be put in place and the statistical calibration of this researcher should be done prior to data collection. However, if two or more researchers are involved in the assessment of agar plates, our results suggest that the protocols using software to undertake plate reading is preferred.

A novel approach for in-office tooth bleaching with 6% H2O2/TiO_N and LED/laser system-a controlled, triple-blinded, randomized clinical trial.

UNLABELLED: The purpose of this randomized, parallel, triple-blinded clinical trial was to compare efficacy and tooth sensitivity (TS) after use of an in-office bleaching agent of 6% hydrogen peroxide containing nanoparticles of nitrogen-doped titanium oxide (HP6) vs. 35% hydrogen peroxide (HP35). Forty-eight volunteers were randomly divided either a HP6 or HP35. Two clinical sessions were performed with an interval of 7 days between them for each group. In each session, two consecutive applications of each bleaching agent were performed and activated by a hybrid LED/laser light. Efficacy was determined by color alteration (ΔE), recorded with reflectance spectroscopy. It was assessed at baseline and after the first and second bleaching session. TS was characterized according to occurrence, intensity, duration, and type. Efficacy was analyzed by repeated measures analysis of variance (ANOVA) and post hoc Bonferroni test, and TS was analyzed by means of chi(2) test (α = 0.05). For HP35, highest and significant values of ΔE were found after bleaching when compared to HP6 (p = 0.002). However, HP35 showed a significantly higher occurrence of TS than HP6 (p = 0.008). Also, intensity and duration were higher in HP35. The majority of volunteers classified the type experienced in their sensitivity in the form of a "shock." The use of HP6 despite reducing efficacy when compared to an in-office bleaching in higher concentration (35%) produced less tooth sensitivity. CLINICAL RELEVANCE: In terms of tooth sensitivity, the use of lower concentrations of in-office bleaching should be the first choice, suggesting greater biocompatibility and safety compared to a conventional HP35.

Photodynamic inactivation of a multispecies biofilm using Photodithazine(®) and LED light after one and three successive applications.

In this investigation, the effectiveness of successive applications of antimicrobial photodynamic inactivation (API) mediated by Photodithazine(®) (PDZ) and LED light was evaluated against a multispecies biofilm formed by Candida albicans, Candida glabrata, and Streptococcus mutans on denture base acrylic resin. Standard cell suspensions (bacteria and yeast) were inoculated on acrylic resin samples, and the biofilm was grown for 48 h (37 °C/75 rpm). API was performed by the administration of PDZ (175 and 200 mg/L) and exposure to 37.5 J/cm(2) of LED light (660 nm). Additional samples were treated with PDZ or LED light only. Untreated control samples were not submitted to light or PDZ. The conditions described were applied once or in three consecutive applications for all groups. Cell viability was determined by colony counts (CFU/mL), metabolic activity, total biomass, and confocal laser scanning microscopy (CLSM). Data were analyzed by a nonparametric two-way ANOVA and Tukey tests (α = 0.05). The results obtained demonstrated a significant effect (p < 0.05) of number of applications and treatment groups for CFU/mL, and S. mutans showed the highest susceptibility to API. The metabolic activity of the multispecies biofilm was significantly reduced (p < 0.05) after API for both numbers of applications, which were also significantly different (p < 0.05) between them. The total biomass of the biofilm was significantly different (p < 0.05) only between groups submitted to one and three API applications. CLSM showed a visual increase of dead cells after API. API-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. Three consecutive applications of API were more effective for reducing the cell viability and the total biomass of multispecies biofilm.

Curcumin-mediated photodynamic inactivation of Candida albicans in a murine model of oral candidiasis.

In vitro investigations of curcumin-mediated photodynamic therapy (PDT) are encouraging, but there is a lack of reliable in vivo evidence of its efficacy. This study describes the photoinactivation of Candida albicans in a murine model of oral candidiasis, using curcumin as a photosensitizer. Forty immunosuppressed mice were orally inoculated with C. albicans and after five days, they received topical curcumin (20, 40 and 80 µM) and illumination with LED light. The use of curcumin or light alone were also investigated. Positive control animals did not receive any treatment and negative control animals were not inoculated with C. albicans. The number of surviving yeast cells was determined and analyzed by ANOVA and Tukey's post-hoc test (α = 0.05). Histological evaluation of the presence of yeast and inflammatory reaction was also conducted. All exposures to curcumin with LED light caused a significant reduction in C. albicans viability after PDT, but the use of 80 µM curcumin associated with light was able to induce the highest log10 reduction in colony counts (4 logs). It was concluded that curcumin-mediated PDT proved to be effective for in vivo inactivation of C. albicans without harming the host tissue of mice.

Phototoxic effect of curcumin on methicillin-resistant Staphylococcus aureus and L929 fibroblasts.

Photodynamic therapy has been investigated as an alternative method of killing pathogens in response to the multiantibiotic resistance problem. This study evaluated the photodynamic effect of curcumin on methicillin-resistant Staphylococcus aureus (MRSA) compared to susceptible S. aureus (MSSA) and L929 fibroblasts. Suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to light-emitting diode (LED). Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 µM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 µM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. The combination of curcumin with LED light caused photokilling of both S. aureus strains and may represent an alternative treatment for eradicating MRSA, responsible for significantly higher morbidity and mortality and increased healthcare costs in institutions and hospitals.

Liquid crystal precursor system as a vehicle for curcumin-mediated photodynamic inactivation of oral biofilms.

Curcumin has great potential as a photosensitizer, but it has low solubility in aqueous solutions. This study reports the antimicrobial efficacy of photodynamic inactivation (PDI) mediated by a curcumin-loaded liquid crystal precursor (LCP) on in situ dental biofilms. Thirty volunteers used intraoral devices containing enamel samples for 48 hours for biofilm formation. The samples were then removed from the device and treated either with LCP with 160 µM of curcumin plus illumination at 18 J/cm2 (C + L+ group) or with LCP without curcumin in the dark (C - L - group). Following this, the biofilm from the samples was plated for quantifying the viable colonies at 37°C for 48 hours. Specific and nonspecific media were used for the presumptive isolation of Streptococcus mutans, Lactobacillus species/aciduric microorganisms, Candida species, and total microbiota. The C + L+ group showed a highly significant (P < .001) reduction in the log10 (colony forming units/mL) values as compared to the C - L - group for all culture media. Hierarchical linear regression indicated that there may be predictors at individual volunteer level explaining the difference in the PDI efficacy among different individuals (P = .001). The LCP system retained curcumin and released it slowly and continuously, thus protecting the drug from photodegradation. LCP with curcumin is considered effective for the photoinactivation of dental biofilms, but the PDI efficacy may differ based on the host's individual characteristics.

Natural versus synthetic curcuminoids as photosensitizers: Photobleaching and antimicrobial photodynamic therapy evaluation.

Antimicrobial photodynamic therapy (aPDT) has been studied as an alternative to combat bacterial resistance to the commonly used antibiotics. aPDT requires the use of a photosensitizer and curcumin is one of the more promising, though the usage of natural curcumin can be inconsistent in certain biomedical uses due to differences in soil condition and turmeric age, besides a large quantity of the plant is necessary to obtain useful amounts of the actual molecule. As such, a synthetic analogue is preferred as it is pure, and its components are better characterized. The present work studied photophysical differences in both natural and synthetic curcumin using photobleaching experiments and searched for whether differences existed in aPDT studies against Staphylococcus aureus. The results showed a faster O2 consumption and a singlet oxygen's generation rate lower by the synthetic curcumin, in comparison with the natural derivative. However, no statistical difference was observed when inactivating S. aureus and these results were following a concentration-based pattern. Thus, the use of synthetic curcumin is indicated, as it can be obtained in controlled amounts and with less environmental impact. Although there are small changes in a photophysical context comparing natural versus synthetic curcumins, we did not observe statistical differences in the photoinactivation of S.aureus bacteria, and reproducibility in biomedical contexts is better achieved with the synthetic analogue.

Curcuminoid-Mediated Antimicrobial Photodynamic Therapy on a Murine Model of Oral Candidiasis.

Antimicrobial Photodynamic Therapy (aPDT) has been extensively investigated in vitro, and preclinical animal models of infections are suitable for evaluating alternative treatments prior to clinical trials. This study describes the efficacy of aPDT in a murine model of oral candidiasis. Forty mice were immunosuppressed with subcutaneous injections of prednisolone, and their tongues were inoculated using an oral swab previously soaked in a C. albicans cell suspension. Tetracycline was administered via drinking water during the course of the experiment. Five days after fungal inoculation, mice were randomly distributed into eight groups; a ninth group of untreated uninfected mice was included as a negative control (n = 5). Three concentrations (20 µM, 40 µM, and 80 µM) of a mixture of curcuminoids were tested with a blue LED light (89.2 mW/cm2; ~455 nm) and without light (C+L+ and C+L- groups, respectively). Light alone (C-L+), no treatment (C-L-), and animals without infection were evaluated as controls. Data were analyzed using Welch's ANOVA and Games-Howell tests (α = 0.05). Oral candidiasis was established in all infected animals and visualized macroscopically through the presence of characteristic white patches or pseudomembranes on the dorsum of the tongues. Histopathological sections confirmed a large presence of yeast and filaments limited to the keratinized layer of the epithelium in the C-L- group, and the presence of fungal cells was visually decreased in the images obtained from mice subjected to aPDT with either 40 µM or 80 µM curcuminoids. aPDT mediated by 80 µM curcuminoids promoted a 2.47 log10 reduction in colony counts in comparison to those in the C-L- group (p = 0.008). All other groups showed no statistically significant reduction in the number of colonies, including photosensitizer (C+L-) or light alone (C-L+) groups. Curcuminoid-mediated aPDT reduced the fungal load from the tongues of mice.

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation. Photodynamic disinfection of complete dentures.

The aim of this study was to evaluate the effectiveness of photodynamic therapy (PDT) for the disinfection of complete dentures. Biofilm samples were collected from dentures of 60 denture users who were randomly divided into four experimental groups (n = 15 each): subjects whose maxillary dentures were sprayed with 50 and 100 mg/l of Photogem® suspension (groups P50S and P100S) and patients whose maxillary dentures were treated with 50 and 100 mg/l of Photogem® gel (groups P50G and P100G). Dentures with photosensitizers were left in the dark for 30 min (pre-irradiation time) and then irradiated with blue LED light at 37.5 J/cm(2) (26 min). Denture samples were taken with sterile cotton swab before (left side surfaces) and after (right side surfaces) PDT. All microbial material was diluted and plated on selective media for Candida spp., Staphylococcus mutans spp., streptococci and a non-selective media. After incubation (48 h/37°C), the number of colony-forming units (cfu/ml) was counted. Microorganisms grown on selective media were identified using biochemical methods before and after PDT. The data were submitted to McNemar and Kruskal-Wallis tests (α = 0.05). No growth after PDT was observed in 60, 53, 47, and 40% of dentures from P100G, P50G, P100S, and P50S groups, respectively. When evidence of microorganisms' growth was observed, PDT regimens eliminated over 90% of microorganisms on dentures. This clinical study showed that PDT was effective for disinfecting dentures.

Long-term effects of simulated gastric juice alternated with brushing on hardness, substance loss, flexural strength and reliability of CAD-CAM monolithic materials.

OBJECTIVES: The purpose of this study is to evaluate, over a simulated 5-year period, the effect of simulated gastric juice alternated with brushing on CAD-CAM monolithic materials considering microhardness, substance loss, flexural strength, and reliability of the materials. METHODOLOGY: Blocks from Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were milled into cylinders and sliced into disks. The EMAX and VS were crystallized, and all specimens were polished with silicon carbide papers and allocated as follows: 1) artificial saliva + brushing or 2) simulated gastric juice (0.113% hydrochloric acid (HCl) solution in deionized water, pH 1.2) + brushing, simulating 1, 3, and 5 years of clinical function. Each year of clinical function was simulated by three repetitions of immersion for 3 hours in artificial saliva or simulated gastric juice followed by 1,217 brushing cycles. The microhardness and substance loss were evaluated at baseline (T0) and at each year by using a Vickers hardness tester and an analytical balance. The biaxial flexural strength (BFS) test was performed in a mechanical testing machine at the end of the 5th year. Weibull modulus was calculated from the BFS data. RESULTS: The microhardness of the LU was not influenced by the treatment, whereas that of the other materials, in certain years, was significantly lower in the gastric juice + brushing groups in comparison with artificial saliva + brushing groups. In general, the materials did not present a significant change in microhardness over time, for either of the treatments. The LU alone showed greater substance loss in the gastric juice + brushing groups for every year. In both treatments, the LU, VE, and EMP exhibited a significant increase in the substance loss over time. The treatment did not affect the BFS of the materials. The gastric juice + brushing decreased the reliability of the VE. CONCLUSIONS: All materials were somehow impaired by the gastric juice + brushing in at least one of the evaluated parameters, except for the BFS. However, in a deeper analysis, the LU would be the least indicated materials, followed by VE, for patients with eating disorders.

Fungicidal effect of photodynamic therapy against fluconazole-resistant Candida albicans and Candida glabrata.

Although photodynamic therapy (PDT) has shown great promise for the inactivation of Candida species, its effectiveness against azole-resistant pathogens remains poorly documented. This in vitro study describes the association of Photogem® (Photogem, Moscow, Russia) with LED (light emitting diode) light for the photoinactivation of fluconazole-resistant (FR) and American Type Culture Collection (ATCC) strains of Candida albicans and Candida glabrata. Suspensions of each Candida strain were treated with five Photogem® concentrations and exposed to four LED light fluences (14, 24, 34 or 50 min of illumination). After incubation (48 h at 37 °C), colonies were counted (CFU ml(-1)). Single-species biofilms were generated on cellulose membrane filters, treated with 25.0 mg l(-1) of Photogem® and illuminated at 37.5 J cm(-2). The biofilms were then disrupted and the viable yeast cells present were determined. Planktonic suspensions of FR strains were effectively killed after PDT. It was observed that the fungicidal effect of PDT was strain-dependent. Significant decreases in biofilm viability were observed for three strains of C. albicans and for two strains of C. glabrata. The results of this investigation demonstrated that although PDT was effective against Candida species, fluconazole-resistant strains showed reduced sensitivity to PDT. Moreover, single-species biofilms were less susceptible to PDT than their planktonic counterparts.