Photo-activated Disinfection Research Articles

Comparison of different modes of photo-activated disinfection against Porphyromonas gingivalis: An in vitro study.

Porphyromonas gingivalis (P. gingivalis), a Gram-negative periodontal pathogen, is frequently detected in subgingival plaques in patients with chronic periodontitis. Considering the insufficient results achieved by the current antimicrobial approaches, this study aimed to compare the susceptibility of P. gingivalis to the different modes of photo-activated disinfection in planktonic culture. Cultures of P. gingivalis were assigned into three main groups of photothermal disinfection with 810 nm laser in continuous mode + EmunDo® (indocyanine green based photosensitizer), 808 nm laser in pulse mode + Perio green® (indocyanine green based photosensitizer); and antibacterial photodynamic therapy with 662 nm laser + Radachlorin® photosensitizer. Then, the bacterial viability was determined by serial dilution method by counting the number of colonies forming units. The results were analyzed by one-way analysis of variance and Tukey test (p < 0.05). All three groups showed significant reduction in the viability of P. gingivalis (p < 0.001). However; this reduction was significantly higher in photothermal therapy with EmunDo®. Both methods of photodynamic and photothermal therapy were successful in Significant eradication of P. gingivalis. Although, photothermal approach was more efficient with EmunDo® in combination with 810 nm laser irradiation.

Endodontic Biofilm - An Enigma to the dentist : A review article

Biofilm can be defined as a sessile multi-cellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self produced matrix of extracellular polymeric substances.1,2 These are very prevalent in the apical root canals of teeth with primary and post-treatment apical periodontitis.3 It can be categorised as intracanal biofilms, extra radicular biofilms, periapical biofilms and biomaterial centered infections.4 The infected root canal harbors a polymicrobial population of aerobic, anaerobic, Gram-positive, and Gram-negative bacteria in a biofilm mode of growth. Bacterias involved are E. faecalis, Coagulase–negative Staphylococcus, S. aureus, Streptococci, P.aeruginosa, fungi, F. nucleatum, P. gingivalis, T. forsythensis, Actinomyces species and P. Propionicum. These are commonly isolated by culture, microscopy, immunological methods and molecular biology methods.3 The microbial communities grown in biofilm are remarkably difficult to eradicate with antimicrobial agents. Therefore, different antimicrobials ranging from antimicrobial irrigants to advanced antimicrobial methods such as lasers, photoactivated disinfection, and nanoparticles are employed in the management of infected root canal systems.4

Case Report: Single visit photo-activated disinfection in regenerative endodontics

Background: Root canal disinfection is considered critical for achieving successful regenerative endodontic procedures. Photo-activated disinfection is a novel disinfection method that can help to achieve the goal of regenerative endodontics. This article reports the clinical and radiographic results after single visit regenerative endodontics using photo-activated disinfection. Methods: An 8.5-year-old girl complained of fractured upper right central incisor. Pulp necrosis was diagnosed on the basis of clinical findings. The root canal was irrigated with sodium hypochlorite solution (1.5%) followed by saline. Then, the canal was dried with paper points. A combination of a photosensitizer solution and low power laser light were applied. EDTA solution was used as a final irrigant. Bleeding was induced, followed by placement of collagen resorbable matrix and white mineral trioxide aggregate. Two days later, the tooth was sealed and restored with permanent filling. Results: Clinical findings revealed no pain on percussion or palpation tests. Radiographic examination revealed an increase in root length, an increase of apical root thickness and apical closure at the 12-month follow-up period. Conclusion: Regenerative endodontics using photo-activated disinfection achieved successful outcomes in the necrotic immature permanent tooth.

Therapeutic and prophylactic effect on periodontal on the background of refusal of smoking

Introduction. The article discusses a new method for estimating the saturation of a therapeutic and prophylactic effect on periodontal on the background of refusal of smoking and its application to assess the parameters of periodontal transitions from the stage of exacerbation to the stage of remission.The objective was to improve the accuracy of low-cost prediction of the effectiveness of interventions in inflammatory periodontal diseases in smoking patients based on the development of a new method for assessing the saturation of therapeutic and prophylactic effects.Methods and materials. To determine the saturation of therapeutic and prophylactic effects on periodontal in smoking patients, it was proposed to estimate the weighted average increase in the reduction of a new series of indicators (concentration of carbon monoxide in exhaled air, clinical indices and frequency of occurrence and nature of exudate of periodontal spaces).Results. The saturation of the therapeutic and prophylactic effect on periodontal on the background of quitting (using anti-tobacco patches) when conducting events with xanthan gel with chlorhexidine or photo-activated disinfection occurs much earlier than the two-week interval. Estimates of the relative frequencies and intensities of therapeutic and prophylactic transitions are obtained when performing procedures against the background of nicotine replacement therapy.Conclusion. The proposed method for assessing the saturation of the therapeutic and prophylactic effect on periodontal in smoking patients allows to take into account additional features of the analyzed process and to carry out a low-cost prediction of the effectiveness of complex therapy.Authors declare no conflict of interest.The authors confirm that they respect the rights of the people participated in the study, including obtaining informed consent when it is necessary, and the rules of treatment of animals when they are used in the study. Author Guidelines contains the detailed information.

Clinical and radiographic evaluation of indirect pulp treatment of young permanent molars using photo-activated oral disinfection versus calcium hydroxide: a randomized controlled pilot trial

BackgroundCalcium hydroxide is the most commonly used material in indirect pulp treatment (IPT). However, its drawbacks required its replacement by other materials.AimThis study aims to estimate clinically and radiographically the success of indirect pulp treatment of young permanent molars with either photo-activated oral disinfection (PAD) or calcium hydroxide.DesignThis Randomized Controlled Pilot Trial included 32 vital first permanent molars with deep caries that were treated by indirect pulp treatment with either PAD (group 1) or calcium hydroxide (group 2). Clinical and radiographic success in addition to newly-formed dentin thickness were evaluated regularly at 2, 6, 9, and 12 months.ResultsThe success for both groups was 100% clinically and radiographically at all follow-up periods. Regarding the mean thickness of newly-formed dentin for both groups at different follow-up periods, there was no statistically significant difference between both groups at 2, 6, 9, and 12 months, with P values = 0.825, 0.146, 0.280, and 0.400, respectively.ConclusionsThe clinical and radiographic success for indirect pulp treatment of young permanent molars with both PAD and calcium hydroxide were comparable.

The Antibacterial Activity of Hydroxyapatite-Tryptophan Complex with Gray Titania by Photocatalysis Using LED Diodes.

Peri-implantitis is an important biologic complication that can lead to implant failure. Proper treatment should effectively kill bacteria, not harm the implant surface, and promote regeneration. Recently, photocatalytic coating without antibiotics or external agents was proposed to be an alternative to antibiotic therapy. The aim of this study was to evaluate the photocatalytic antibacterial effect of a new titanium implant coating made from hydroxyapatite-tryptophan complex and gray titania, which was activated by two visible lights. Titanium alloy substrate was plasma sprayed with hydroxyapatite (80 wt%) and dititanium trioxide (20 wt%) and then pressed with tryptophan. Three bacteria related to peri-implantitis, Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans, were used in this study. Six conditions were tested: (1) control group (only bacteria), (2) photocatalytic sample in darkness (bacteria and coated sample in darkness), (3) red laser for 15 minutes (bacteria irradiated with photoactivated disinfection [PAD] light, 650-nm wavelength), (4) broadband light-emitting diode (LED) for 15 minutes (bacteria irradiated with broadband LED, peak wavelength at 470 nm), (5) photocatalysis by red laser for 15 minutes (bacteria and coated sample irradiated with PAD light), and (6) photocatalysis by broadband LED for 15 minutes (bacteria and coated sample irradiated with broadband LED). After 15 minutes of irradiation, photocatalytic antibacterial effects were evaluated by total viable bacterial count, adenosine triphosphate (ATP) assay, and LIVE/DEAD assay. The number of all bacteria tested was significantly decreased by the photocatalytic effect of both visible light sources (P < .05). For P gingivalis, viable bacteria of lethal photosensitization groups were also significantly decreased (P < .05), especially when using the broadband LED. However, the coating material itself did not have antibacterial properties without light activation. There was no significant difference in ATP among groups (P > .05). LIVE/DEAD staining showed that red fluorescent bacterial cells were present in photocatalytic groups from the two light sources. Photoactivated hydroxyapatite-tryptophan complex and gray titania as a photocatalytic coating has antibacterial effects on bacteria associated with peri-implantitis.

A randomized clinical trial of antimicrobial efficacy of photoactivated disinfection, conventional endodontic irrigation and their combination in primary endodontic infections

Aim: The aim of this study is to evaluate and compare the antimicrobial efficacy of photoactivated disinfection (PAD), conventional irrigation (CEI), and combination of both against primary endodontic infections in vivo. Methods: Active controlled and parallel design trial was registered with Clinical Trials Registry India under reference no. CTRI/2018/08/015478. Forty-eight qualified patients were randomly divided into three groups (n = 16 each) using the lottery method, Group-I: CEI, Group-II: PAD, Group-III: CEI and PAD. Access opening and working length were determined, and preinstrumentation sample (S1) was taken by inserting sterile paper point into the canal. Postinstrumentation sample (S2) was collected following biomechanical preparation and irrigation with respective interventions. Microbiological samples (S1, S2) were plated on brain heart infusion agar. Colony-forming units were counted using the classic bacterial counting method, and percentage bacterial reduction was determined. Statistical Analysis: Inter- and intra-group comparison was made using repeated measures of ANOVA. Post hoc Tukey analysis was done for pairwise comparison with P Results: In the intragroup comparison, statistically significant reduction was seen at S2 among all experimental groups. However, in intergroup comparison, mean bacterial reduction in Group III was significantly lower than the other groups. This difference was statistically significantly better between Group I and Group III; Group II, and Group III. However, no statistically significant difference was seen between Group I and Group II. Within the limitations of this study, it can be concluded that a combination of CEI and PAD showed significantly better antimicrobial activity against primary endodontic infections and can be recommended as an adjunct to facilitate maximum root canal disinfection.

Photo-activated disinfection with light-emitting diode reduces some key periodontal pathogens in chronic periodontitis

The aim of the present study was to evaluate the potential of minimally invasive periodontal treatment using repeated photo-activated oral disinfection (PAD) with red light emitting diodes as an adjunct to ultrasonic scaling (US) in the treatment of chronic periodontitis. In a single-centred, randomized clinical trial involved 40 patients with untreated chronic periodontitis received US with repeated 3 episodes of PAD (test group) or US alone (control group). Clinical parameters (plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD), clinical attachment level (CAL)) were recorded for 12 months and subgingival biofilm analyses for five periodontal pathogens (A. actinomycetemcomitans (Aa), P. gingivalis (Pg), P. intermedia (Pi), T. forsythia (Tf), T. denticola (Td)) were performed for 6 months. Supportive periodontal treatment (SPT) was repeated every 3 months during the clinical trial, additional one episode of PAD was also applied in the test group. Both treatment modalities improved clinical parameters after 3 months and SPT maintained favourable clinical outcomes during 12 months. There were no statistical significant differences between the treatment groups. Statistical significant reduction of Aa, Pg, Tf, Td (p<0.05) was observed in the test group. In moderate pockets significant reduction of Pg, Tf, Td (p<0.05) and in deep periodontal pockets reduction of Pg, Pi, Td (p<0.05) was observed. Within the limits of the present study it may be concluded that the addition of PAD to US significantly reduced some key periodontal pathogens, however, patients with a history of periodontitis should be on SPT every 3-4 months.

Оптимізація проведення фотоактивованої дезінфекції тканин пародонта за допомогою розробленої опромінюючої насадки

Мета: провести аналіз сучасних насадок для опромінення тканин пародонта, що застосовуються для фотоактивованої дезінфекції, визначити позитивні та негативні якості наявного обладнання, на основі отриманих даних розробити та виготовити насадку, яка б дала можливість ефективнішого застосування в курації генералізованих захворювань пародонта.Матеріали та методи. На основі аналізу даних нами була розроблена схема насадки, яка дає змогу обробляти ділянки пародонта в ділянці 4–6 зубів, рівномірно розподіляє необхідну потужність лазерного випромінювання, та дає змогу працювати в важкодоступних ділянках порожнини рота. Також була розраховані необхідні параметри які дозволять отримати пляму лазерного випромінювання з заданими характеристиками. Внаслідок чого була виготовлена насадка власної конструкції. Було проведено експеримент, де фіксувався час затрачений на процедуру фотоактивованої дезінфекції в пацієнтів з генералізованими захворюваннями пародонту (пародонтит першого ступеня) , в якому були використані зразки трьох основних видів насадок, та власне розроблена нами насадка.Результати. Було розроблено,сконструйовано та виготовлено насадку для опромінення тканин пародонта. Проведено експеримент, де фіксувався час затрачений на процедуру фотоактивованої дезінфекції в пацієнтів з генералізованими захворюваннями пародонту (пародонтит першого ступеня) , в якому були використані зразки трьох основних видів насадок, та власне розроблена нами насадка. В результаті розрахунків були отримані наступні дані: на обробку однієї пародонтальної кишені з використанням насадки першого типу було затрачено в середньому 120 секунд; на обробку пародонтальної кишені з використанням насадки другого типу – 58 секунд; обробка насадкою третього типу в середньому займала 68 секунд. Обробка ж пароднотальної кишені сконструйованоюнами насадкою займала 34 секунди, що на 41 % швидше від найефективнішої доступної насадки другого типу.Висновок: сконструйована нами насадка дозволяє значно скоротити час проведення сеансу фотоактивованої дезінфекції та розширити внаслідок цього сферу застосування даного методу. Ми бачимо перспективу застосування даної методики для лікування та профілактики захворювань пародонту, включивши фотоактивовану дезінфекцію в протокол професійної гігієни порожнини рота для всіх груп пацієнтів. Дослідження ефективності даного впливу на разі тривають.Ключові слова: Пародонт, фотоактивована дезінфекція, насадка, фотосенсибілізатор

Treatment efficacy of photoactivated disinfection versus Salvadora persica gel in experimental gingivitis.

This clinical trial aimed to study the comparison of clinical gingival inflammatory scores and levels of pathogenic bacteria with professionally administered plaque removal (PAPR) with photoactivated disinfection (PAD) and Salvadora persica (SP) gel application in experimentally induced gingivitis. Twenty-five non-smoking patients underwent an 8-week experimental gingivitis trial that consisted of 14 days of undisturbed plaque accumulation and a 6 week of resolution phase following the three treatment modalities. The treatment protocols included PAPR with adjunctive PAD, SP gel application and PAPR alone. Clinical gingival inflammatory parameters including plaque index (PI) and bleeding on probing (BOP) were assessed. Microbiological parameters included the log count of five periodontal pathogens in the plaque from all experimental sites. No significant difference in plaque levels was observed between PAD, SP and PAPR at 2- and 6-weeks following treatment. The magnitude of the decrease was statistically significant at 6 weeks for SP (P = 0.02). The median number of residual BOP+ sites was higher at PAD and PAPR compared to SP at either 2-weeks (2.75 and 1.25, respectively; P = 0.039) or 6 weeks (2 and 1, respectively; P = 0.044) following treatment administration. Counts of all bacteria reduced until 2 weeks with significantly greatest reduction seen in the PAD group and this was maintained until 6 weeks of follow-up. The log CFU/mL values for all bacterial counts significantly reduced for SP group, however, it did not show significant reduction when compared with PAD but had greater extent when compared with PAPR group. Both PAD and SP gel application improved clinical gingival inflammatory parameters in experimental-induced gingivitis. However, PAD helped to reduce bacterial counts, while SP had significant impact on bleeding in gingival inflammation.

Evaluation of the outcome of various laser therapy applications in root canal disinfection: A systematic review.

Any successful endodontic therapy requires elimination of the endodontic biofilms through meticulous root canal disinfection methods. Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are the most common effective irrigants, in removing smear-layer from the coronal and middle thirds of the dental canals but reduced considerably towards the apical one third. In recent years, newly alternative treatment modalities have been proposed, including high-power lasers and antimicrobial photodynamic therapy (aPDT). Our work was conducted to evalaute the outcome of root canal disinfection in relation to the efficacy of various treatment modalities. Furthermore, every effort was made to present an overview of the aPDT outcomes, as a model for this application, and to propose laser parameters protocol with positive results. The electronic databases PubMed was searched from January 2013- January 2019. Our inclusive criteria based on laser therapy applications, as a model for root canal disinfection. The search terms utilised various combinations as follows: photodynamic therapy or antimicrobial photodynamic therapy or photoactivated disinfection or light activated disinfection or laser activated disinfection or laser therapy, and endodontic. The results of this systematic review concluded that the effectiveness of aPDT and various laser wavelengths protocols, in removing endodontic biofilms from infected root canals, remains unattainable. Study concluded that the combination of aPDT with antimicrobial irrigants could provide a synergetic effect. However, due to the heterogeneity of the selected studies and their limitations, in terms of lack of standardised protocol or discrepancy in the methodology, authors suggest further validated approaches to achieve optimal outcomes.

Antimicrobial action of photoactivated C-Phycocyanin against Enterococcus faecalis biofilms: Attenuation of quorum-sensing system.

The limitations of conventional chemo-mechanic therapy in endodontic have given rise to introduce and develop photoactivated disinfection (PAD) as an adjunctive treatment. The objective of this ex vivo study was to evaluate the effects of PAD using C-Phycocyanin, as a natural photosensitizer, on biological activities and expression of quorum-sensing system gene fsrB of Enterococcus faecalis. A total of 52 extracted single-rooted human premolar teeth were divided into five groups (n = 10) and were incubated with E. faecalis for biofilm formation, and they were treated according to following groups; A. C-PC only; B. Diode laser only (at wavelengths of 635 nm); C. PAD (C-PC plus diode laser); and D. Sodium hypochlorite (NaOCl). E. Control group (not treatment). Two remaining teeth were used to confirm E. faecalis biofilm formation in the root canal system by scanning electron microscopic. The effects of each treatment were measured on viability and expression level of fsrB gene of E. faecalis using microbial cell viability and quantitative real-time PCR assays, respectively. Additionally, intracellular reactive oxygen species (ROS) production was measured using 2',7'-dichlorfluorescein-diacetate (DCFH-DA) fluorescent probe. The C-PC alone and C-PC-PAD reduced the culture viability of E. faecalis by 38.1% and 89.45%, respectively (both; P < 0.05). According to the Bonferroni post hoc test, a significant difference in the reduction of E. faecalis count was observed between C-PC-PAD and other groups (P < 0.05), except the NaOCl group (P > 0.05). As well as, photoexcited C-PC in PAD could increase (3.8- fold) the intracellular ROS production in E. faecalis compared to the control group (P < 0.05). C-PC-PAD at sub-significant inhibitory concentration and NaOCl at sub-lethal dose could significantly decrease the expression levels of fsrB by 10.8- and 11.4-fold, respectively. Our data support that C-PC alone and C-PC-PAD can serve as a potent irrigation solution and a disinfection method, respectively for microbial reduction and promising adjunct therapy in endodontic infection treatment against E. faecalis with clinical applications for infection control in endodontics.

Antimicrobial efficacy of photodynamic therapy, diode laser, and sodium hypochlorite and their combinations on endodontic pathogens.

Sterilization of the root canal system is of prime importance for a successful root canal therapy. Lasers and photodynamic therapy (PDT) have become the latest choice to eradicate microorganisms in the root canal. To evaluate and compare the antimicrobial activity of diode laser, photodynamic therapy, and sodium hypochlorite along with their combinations on endodontic pathogens: Enterococcus faecalis and Streptococcus mutans. A total of 120 uniradicular teeth were stored in 5.2% NaOCl solution to remove organic residues and the crowns were sectioned at the cemento-enamel junction (CEJ) to obtain root canal length of 15 mm. Canals were shaped using step-back technique up to #40 K-file and were autoclaved. The selected teeth (specimen) were randomly divided into two equal groups with sixty teeth being inoculated with E. faecalis (Group E) and remaining sixty teeth with S. mutans (Group S). Further, the groups were subdivided according to the disinfection technique used. Ten teeth from each subgroup were disinfected with a diode laser, photo activated disinfection (PAD), sodium hypochlorite, a combination of sodium hypochlorite and diode laser, a combination of sodium hypochlorite and photo activated disinfection respectively. Ten teeth in each group served as control without any disinfection. The treated specimens were transferred to test tubes containing 5 ml sterile Luria Bertani broth, incubated and the bacterial count, optical density in each root specimen was calculated and compared. The pairwise comparison of colonies across the subgroups was done by the Kruskal-Wallis test and within the subgroups was carried out using the Mann-Whitney U test. The statistical implication was tested at 5% and the study was performed using SPSS 18.0 ver. (SPSS Inc.). A significant reduction (98%) in the E. faecalis count was observed when the NaOCl was used in combination with the diode laser or PAD. PAD along with 3% NaOCl presents the advantage of utilizing a lower wavelength laser beam. Hence, PAD in combination with NaOCl can be an alternative and better option for root canal disinfection for both the endodontic pathogens, E. faecalis and S. mutans.

Photoactivated disinfection in periodontal treatment: A randomized controlled clinical split-mouth trial.

Photoactivated disinfection (PAD) could support the periodontal treatment outcome. The effect of the light emitting diode (LED) as an innovative light source in PAD is under discussion. The aim of this study was to evaluate the clinical and microbiological effect of adjunctive PAD in the treatment of periodontitis with a red LED as light source. Twenty patients with periodontitis completed this split-mouth study. The left and right side of the jaws were randomly assigned to either test or control group. After conservative periodontal treatment in both groups, the test group received two sessions of adjunctive PAD (red LED, 635nm, photosensitive dye, 0.01% tolonium chloride), whereas the control group received no adjunctive PAD. The parameters of clinical periodontal examination-including probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP) and microbiological assays (PCR) were evaluated before and after treatment. After 3 months, both treatment groups showed significant improvements regarding BOP, PD, and CAL compared to baseline, with no significant difference between control and treatment group. The recolonization of Porphyromonas gingivalis and Treponema denticola was reduced after adjuvant treatment, but not significantly. The positive effect of adjunctive PAD regarding clinical parameters was reported in recent trials. In this study and with the current settings, both treatment groups showed similar clinical results after initial periodontal treatment, without beneficial effect of adjunctive PAD.

Optimization of the terms of supportive periodontal therapy using photoactivated disinfection

Relevance: to indentify if periodontal treatment which is presented by photoactivated disinfection (PAD) adjunctively to scaling and root planing (SRP) yield better outcomes than ozone therapy as an adjunct to SRP in periodontitis.Materials and methods: we examined 57 (mean age 49,3 ± 1,02) patients with chronic periodontitis, divided into groups, SRP + PAD, SRP + ozone therapy and SRP alone. Subgingival plaque samples were subjected to DNA extraction and real time PCR amplifcation for detection Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), Treponema denticola (Td), Aggregatibacter actinomycetemcomitans (Aa). The amount of periodontopathogens and clinical parameters including plaque index, clinical attachment loss, pocket depth, bleeding on probing were measured at baseline, after 40, 90 and 180 days.Results: the results in groups of PAD+SRP and ozone therapy+SRP showed an improvement in all clinical parameters PI, BOP, PD, CAL and the quantity of Pg, Td and Tf compared to the control group during an observation period.Conclusion: the results showed additional benefts from PAD and ozone therapy as an adjunctive treatment to SRP for patients of chronic periodontitis.

Adjunctive antimicrobial photodynamic therapy to conventional chemo-mechanical debridement of infected root canal systems: A systematic review and meta-analysis

To investigate the efficacy of antimicrobial photodynamic therapy (aPDT) adjunctive to conventional chemo-mechanical debridement of root canal system in patients with endodontic infections. A meta-analysis was done according to the Cochrane Collaboration recommendations and PRISMA statement. Two independent reviewers performed an extensive literature search on electronic databases of MEDLINE, EMBASE, and SCOPUS up to January 2019. The search strategy was done from the following terms: antimicrobial photodynamic therapy OR photo-activated disinfection AND root canal therapy OR endodontic therapy OR root canal infection OR endodontic infection. The I2 test was used for determine the inter-study heterogeneity. Publication bias assessment carried out on the studies using the Egger's regression test. Sensitivity analysis of 10 randomized clinical trials (RCTs) revealed differences in microbial load reduction (0.143, 95% CI [0.06, 0.30], P = 0.000) in favor of aPDT plus conventional chemo-mechanical debridement. A high degree of heterogeneity (P = 0.000; Q- value = 154.74; I2 = 94.18%) was noticed among photosensitizer and light parameters. Subgroup analysis demonstrated the absence of heterogeneity in RCTs, with low risk of bias for microbial load reduction gain. No evidence of publication bias was determined. Although the aPDT parameters may vary from one RCT to the next, all studies found a reduction in microbial load with adjunctive use of aPDT; however, further high-quality RCTs focused on the standardized aPDT parameters are needed.

Analysis of glucosyltransferase gene expression of clinical isolates of Streptococcus mutans obtained from dental plaques in response to sub-lethal doses of photoactivated disinfection.

Dental caries is a disease caused by a group of oral streptococcal microorganisms, primarily Strptococcus mutans. Photoactivated disinfection (PAD) has been proposed as a conservative method for treatment of carious lesions. Therefore, the aim of this study was to assess the effectiveness of indocyanine green (ICG)- and toluidine blue O (TBO)-PAD as supplementary tools in reducing the bacterial load and expression profiling of the gene associated with the biofilm formation in S. mutans. S. mutans strains were isolated from dental plaque samples collected from 212 patients through conventional biochemical tests and molecular methods. After identification, S. mutans strains were photosensitized in vitro with TBO and ICG, which were excited at a specific light wavelength based on the photosensitizer. After evaluating doses of TBO- and ICG-PAD contributing to sub-significant reduction of CFU/mL, ROS levels were measured with DCFH-DA fluorescent probe. Eventually, TBO- and ICG-PAD effects on the gtfB gene expression were assessed using real-time quantitative reverse transcription polymerase chain reaction. S. mutans strains were isolated from 50 (23.5%) patients. In this study, maximum doses of TBO- and ICG-PAD contributing to sub-significant reduction of CFU/mL against S. mutans strains were 23.12 μM/mL TBO at fluence of 68.75 J/cm2 and 20.15 μM/mL ICG at fluence of 31.2 J/cm2. According to the results, 3.8- and 6.1-fold increases in the fluorescence were observed in ICG and TBO treated cells compared to the control, respectively. The expression of gtfB was down regulated to approximately 3.9- and 8.25-fold following treatment with TBO- and ICG-PAD, respectively. The gtfB gene expression profiling decreased in the bacterial cells, with ICG-PAD causing a greater reduction. PAD may be a promising therapy for dentinal carious lesions.

Photoactivated water-disinfecting, and biological properties of Ag NPs@Sm-doped ZnO nanorods/cuttlefish bone composite: In-vitro bactericidal, cercaricidal and schistosomicidal studies

Herein, eco-friendly composite was synthesized by embedding silver (Ag) nanospheres onto aragonitic cuttlefish bone (CB)-stabilized samarium doped zinc oxide (Sm-doped ZnO) nanorods. The operating interaction profile and the photoactive behavior of this nanocomposite were assessed via XRD, FTIR, Raman, TEM, FE-SEM, DLS, DRS and PL techniques. Locality of Sm-doped ZnO and its attaching modes to the cuttlefish bone lamella were highly dominated by embedding Ag NPs that encouraged Zn2+ Lewis acid sites to electrostatically interact with aragonite carbonates in the channeled porous CB system. Such interacting approach enhanced photoactivity of Sm-doped ZnO by lowering its energy band gap (from 3.26 eV for Sm-doped ZnO/CB to 2.12 eV for Ag@Sm-doped ZnO/CB). Besides, plasmon-induced silver electrons provided Sm-doped ZnO by extra photosensitivity. Ag@Sm-doped ZnO/CB nanocomposite exhibited pronounced photo-activated disinfection efficiencies for Staphylococcus aureus (80%), Pseudomonas aeruginosa (60%), and Schistosoma mansoni cercariae (100%) linked with progressive demolition in cercarial body. Such nanocomposite also possessed exterminating action against Schistosoma mansoni adult worms serving near 100% worm-mortality accompanied by significant disintegration of worm body. These findings were successfully drawn Ag@Sm-doped ZnO/CB as an efficient weapon in the biocides arsenal being even capable of destructing pathogenic bacteria and parasites in dark- and photo- conditions.

PR416: Efficacy of adjunctive photoactivated disinfection versus ozone therapy in patients with chronic periodontitis

PR416: Efficacy of adjunctive photoactivated disinfection versus ozone therapy in patients with chronic periodontitis

Expression patterns of oxyR induced by oxidative stress from Porphyromonas gingivalis in response to photo-activated disinfection.

IntroductionPorphyromonas gingivalis, an important endodontic pathogen, may be exposed to sublethal doses of photo-activated disinfection (sPAD) during root canal therapy. Such an exposure can affect bacterial survival and virulence features. In this study, we evaluated the effect of sPAD-related oxidative stresses on the expression of oxidative stress response gene (oxyR) in P. gingivalis clinical isolates surviving in vitro photodynamic treatment.Materials and methodsTo determine the sPAD, 16 clinical P. gingivalis isolates photosensitized with toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) were irradiated with specific wavelength and energy density of diode laser corresponding to the photosensitizers following bacterial viability measurements. The effects of sPAD on the expression ratio of oxyR of 16 clinical P. gingivalis isolates were then assessed using quantitative real-time PCR (qRT-PCR) assay.ResultsMaximum values of sPAD against P. gingivalis were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm2, respectively, for TBO-, ICG-, and MB-sPAD (P>0.05). ICG-, MB-, and TBO-sPAD could increase the oxyR gene expression of the clinical P. gingivalis isolates 12.3-, 5.6-, and 8.5-fold, respectively. ICG-sPAD increased the expression of oxyR gene in clinical isolates of P. gingivalis ~1.5- and 2-fold higher than TBO- and MB-sPAD, respectively.ConclusionOur results showed that upregulation of oxyR during sPAD may lead to better survival and increased pathogenicity of P. gingivalis isolates. Therefore, selection of appropriate photo-activated disinfection dosage should be considered for the successful treatment of endodontic infection.