Photo-activated Disinfection Research Articles

Comparative Assessment of the Antimicrobial Efficacy of Photoactivated Disinfection Employing Distinct Photosensitizers: A Morphological Analysis Using Scanning Electron Microscopy and Confocal Laser Scanning Microscopy

Comparative Assessment of the Antimicrobial Efficacy of Photoactivated Disinfection Employing Distinct Photosensitizers: A Morphological Analysis Using Scanning Electron Microscopy and Confocal Laser Scanning Microscopy

Photoactivated disinfection procedure for denture stomatitis in diabetic rats.

To study the efficacy of PADTM Plus-based photoactivated disinfection (PAD) for treating denture stomatitis (DS) in diabetic rats by establishing a diabetic rat DS model. The diabetic rat DS model was developed by randomly selecting 2-month-old male Sprague-Dawley rats and dividing them into four groups. The palate and denture surfaces of rats in the PAD groups were incubated with 1 mg/mL toluidine blue O for 1 min each, followed by a 1-min exposure to 750-mW light-emitting diode light. The PAD-1 group received one radiation treatment, and the PAD-2 group received three radiation treatments over 5 days with a 1-day interval. The nystatin (NYS) group received treatment for 5 days with a suspension of NYS of 100,000 IU. The infection group did not receive any treatment. In each group, assessments included an inflammation score of the palate, tests for fungal load, histological evaluation, and immunohistochemical detection of interleukin-17 (IL-17) and tumor necrosis factor (TNF-α) conducted 1 and 7 days following the conclusion of treatment. One day after treatment, the fungal load on the palate and dentures, as well as the mean optical density values of IL-17 and TNF-α, were found to be greater in the infection group than in the other three treatment groups (P < 0.05). On the 7th day after treatment, these values were significantly higher in the infection group than in the PAD-2 and NYS groups (P < 0.05). Importantly, there were no differences between the infection and PAD-1 groups nor between the PAD-2 and NYS groups (P > 0.05). PAD effectively reduced the fungal load and the expressions of IL-17 and TNF-α in the palate and denture of diabetic DS rats. The efficacy of multiple-light treatments was superior to that of single-light treatments and similar to that of NYS.

Effectiveness of curcumin as photodynamic therapy for endodontic procedures: a narrative review

Endodontic therapy is performed by biomechanical preparation and intracanal medication; however, residual bacteria can be compromised due to their ability to adhere to the root canal walls. Therefore, photodynamic therapy has gained popularity because of its good ability to prevent and eradicate microbial infections by using a light-activated dye. Objective: Analyze and to update the information on the effect of curcumin in photodynamic therapy in root canal treatment. A literature search was carried out in PubMed/MEDLINE, Scopus, Ebsco, Science Direct, and LILACS databases using the keywords "curcumin", "turmeric", "photodynamic", "photochemotherapy", "photoradiation", "photoactivated disinfection", "root canal disinfection", "root canal therapy", "endodontics" in both Spanish and English, from 2018 to 2023. Information from the last five years was collected with the aim of updating the study topic. 749 articles were examined using inclusion and exclusion criteria, of which only 50 met these criteria and were analyzed. Current studies show the effects of therapy on the contamination of the root canal biofilm with E. faecalis, demonstrating that photoactivated curcumin promotes the disruption of the biofilm and reduction of Colony-Forming Units. Curcumin as a photosensitizer demonstrates a potential antibacterial effect significantly decreasing the viability of microbial cells and the vitality of biofilms.

Disinfection Efficacy of Laser Activation on Different Forms and Concentrations of Sodium Hypochlorite Root Canal Irrigant against Enterococcus faecalis in Primary Teeth.

Photoactivated disinfection with sodium hypochlorite (NaOCl) has improved primary root canal treatment outcomes. This in vitro study aims to assess and compare the disinfecting efficacy of 2.5% sodium hypochlorite solution and 5.25% sodium hypochlorite gel, without laser activation and accompanied by laser activation, on Enterococcus faecalis-contaminated primary teeth root canals. After one month of incubating extracted teeth specimens with E. faecalis, 36 specimens were randomly divided into two groups: Group A (conventional method without laser-activated irrigation) and Group B (with laser-activated irrigation). Each group was further divided into three subgroups, with six samples in each subgroup. Subgroup 1 received irrigation with normal saline, Subgroup 2 with 2.5% sodium hypochlorite solution, and Subgroup 3 with 5.25% sodium hypochlorite gel. Diode laser activation at 810 nm was used in Group B. Bacterial colony counts were measured before and after the intervention. Student's t-test and one-way analysis of variance (ANOVA) with Tukey's post hoc test were used for statistical analysis. The significance level was set at p < 0.05. Microbial analysis revealed no bacterial growth in samples irrigated with 5.25% sodium hypochlorite gel activated with the laser. Activation with the laser significantly (p = 0.02) improved the disinfection ability of the irrigant compared to the non-activation group. The disinfection ability of sodium hypochlorite gel was better than that of saline (p = 0.02); however, it was comparable to that of sodium hypochlorite solution (p = 0.67). Conclusion: Root canal irrigation with 5.25% sodium hypochlorite gel activated with an 810 nm diode laser resulted in complete eradication of Enterococcus faecalis, indicating its effectiveness as an endodontic disinfection treatment modality.

Potentialities of photoactivated disinfection in dentistry

Infection control is an essential part of dental practice. Oral antiseptics should be highly effective against the most common oral pathogens without causing microbial resistance, biocompatible with the human tissues with no interaction with fillings materials. Photoactivated disinfection (PAD) is based on activation of photosensitizers - specific substances releasing active oxygen forms after absorption of the light. The active oxygen forms destroy bacterial cell structures without affecting human cells. The overwhelming majority of Russian and international researchers have reported high effectiveness of PAD in periodontics, implantology and endodontics, whereas the use of PAD in caries treatment and prevention is not so fully understood yet. Earlier studies have demonstrated high sensitivity of cariogenic bacteria to PAD, suggesting it as an additional minimally invasive caries therapy improving treatment effectiveness. PAD spares dental tissues without reduction in the effectiveness of disinfection. It is particularly important in treatment of deep carious lesions and disinfection of thin dentine layer near the pulp. Effectiveness of PAD in caries treatment has been demonstrated for both permanent and deciduous dentition. PAD doesn't affect bond strength to fillings, improves plasticity of dental pulp and dental hard tissues mineralization in children. Effective control of a wide range of bacteria without causing resistance makes PAD a prospective method of treatment and prevention of caries.

Diode Lasers in Dentistry: Current and Emerging Applications

OBJECTIVE: The objective of this review is to describe basic diode laser physics and to delineate the application of diode lasers in dentistry. REVIEW: Over the past few decades lasers have become a popular alternative to conventional methods owing to the advantages they carry such as decreased cellular destruction and tissue swelling, minimal bleeding, enhanced visualization of surgical sites and reduced requirement for suturing. Among the various lasers in dentistry, diode lasers are currently the most commonly used, with applications extending from soft tissue procedures to photo-activated disinfection of periodontal pockets, endodontics and laser-assisted tooth whitening. With its versatility and numerous benefits, small size, ease of operation and, relative and cost-effectiveness when compared to other lasers, the diode laser is proving itself as a valuable addition to dental setups. CONCLUSION: The diode laser provides a relatively pain-free minimally invasive technique for removal of soft tissue lesions such as exophytic lesions and operculum, gingival depigmentation, implant exposure, biostimulation, canal disinfection in endodontics and teeth whitening.

SURGICAL AND NON-SURGICAL LASER PREPROSTHETIC PERIODONTAL PREPARATION. LOW-LEVEL LASER THERAPY AND PHOTOACTIVATED DISINFECTION

Background: Clinical success and functional durability of indirect restorations depend on optimal dental health before the prosthetic treatment and the manipulation of the gingival tissues. The aim of the current article is to review the surgical and non-surgical laser methods that can be applied as periodontal preparation in fixed prosthodontics. Review results: Preprosthetic periodontal preparation includes conventional periodontal therapy (non-surgical) and periodontal resective (surgical) procedures - soft and hard tissue crown lengthening. The advantages of lasers in the latter are reduced bleeding, less postoperative discomfort and faster healing. Non-surgical preprosthetic preparation, on the other hand, aims at microorganisms’ level reduction. The variety of protocols, which reduce the microbial number significantly, show photoactivated disinfection as adjunctive therapy in infection treatment, especially in patients with resistant microorganisms and anatomical complications. Conclusion: Lasers can be applied as an alternative to the classic surgical and non-surgical means for periodontal procedures. Low-level laser therapy and photoactivated disinfection ensure faster bacteriolysis and affect the microorganisms locally, whereas systemic medicines influence the whole organism. Photodynamic therapy does not require maintaining high concentrations of the photosensitizer in the infected area, as it is when using antiseptics and antibiotics.

An Experimental Study of Photoactivated Disinfection in the Treatment of Acute Pseudomembranous Stomatitis.

To investigate photoactivated disinfection (PAD) to treat acute pseudomembranous stomatitis, an animal model was established. Six-week-old male ICR mice were inoculated with Candida albicans under immunosuppression then divided into three groups (15 mice per group). Pseudomembranous area was measured, then mice had 1 mg mL-1 toluidine blue solution spread on the area, left for 1 min (PAD-1 group) or 2 min (PAD-2 group), then irradiated with a 750 mW LED red light for 1 min, a control group received no treatment. Fungal load was measured immediately; after 48 h of observation pseudomembranous area and fungal load were measured. The mice were sacrificed and histopathological examination was performed. Before treatment, pseudomembranous area scores were similar (3 to 4 points) in all groups; 48 h after treatment, the treatment groups' scores were lower (1 to 2 points) than the control group (3 to 4 points, P < 0.05). Immediately after treatment and 48 h later, the fungal loads of the treatment groups were lower than the control group (both P < 0.05). Histopathology of the treatment groups improved more than controls. The treatment groups' results were similar. Therefore, this method of PAD, with short treatment time, reduced the fungal load and pseudomembranous area scores in a mouse model of acute pseudomembranous stomatitis and may have clinical potential.

Exploring Photoactivated Disinfection-Induced Bystander Effects on Microbial Biofilms of Aggregatibacter actinomycetemcomitans.

Photoactivated disinfection (PAD) has been indicated as one of the potential methods for the initial periodontal therapy in periodontitis and peri-implantitis, which may have bystander effects on the viability of off-target cells. In this article, we evaluated the effects of PAD-induced bystander on biofilm formation ability, metabolic activity, and gene expression level of Aggregatibacter actinomycetemcomitans as one of the bacteria involved in causing periodontitis and peri-implantitis. Bystander effects induced by bacterial cell suspension (BCST) obtained from treated A. actinomycetemcomitans culture with indocyanine green (ICG)-PAD on biofilm formation of A. actinomycetemcomitans were determined using microbial viability assay. Additionally, metabolic activity and changes in gene expression of fimA were assessed using the XTT reduction method and quantitative real-time PCR (qRT-PCR) assay, respectively. The results revealed that 1000 and 125 μg/mL of ICG combined with diode laser irradiation for 1 min were significant and sub-significant reduction doses of ICG-PAD, respectively, versus A. actinomycetemcomitans. The biofilm formation ability, metabolic activity, as well as, expression level of fimA gene in A. actinomycetemcomitans were significantly reduced after treatment by a significant reduction dose of ICG-PAD-induced bystander effects (P<0.05). ICG-PAD could significantly reduce the microbial population, cell metabolic activity, and gene expression through the bystander effects and could enhance the efficiency of PAD as an adjunct approach for the nonsurgical treatment of periodontitis and peri-implantitis.

A Review on Root Canal Irrigation Solutions in Endodontics

Introduction: This paper aims to review the different characteristics of root canal irrigants including sodium hypochlorite (NaOCl), chlorhexidine (CHX), hydrogen peroxide (H2O2), iodine potassium iodide (IKI), antibiotic-based irrigants, photo-activated disinfection, electrochemically activated water, and QMix. The literature on root canal irrigation solutions in the context of endodontics up to June 2020 was reviewed using PubMed and MEDLINE. NaOCl was identified as the most likely effective irrigation solution that could be used for endodontics. Its antimicrobial activity is at least comparable or even greater than that of other common irrigants. Tetraclean was also proposed to be more effective than CHX against endodontic microorganisms. In addition, Hypoclean was suggested as the most potent and effective irrigant against Candida albicans. Similarly, IKI was introduced as a successful irrigant in killing Candida albicans and Enterococcus faecalis. MTAD is also known to be effective in smear layer removal as well as against the growth of Enterococcus faecalis. EDTA is also considered to have limited antimicrobial activity.

Effect of Different Final Irrigation Activation Methods on Root Canal Cleanliness

Aim: to evaluate canal cleanliness after using manual dynamic activation, passive ultrasonic irrigation and photoactivated disinfection in comparison with conventional needle irrigation, using scanning electron microscopy Methods: Sixty single rooted human premolars with nearly straight single canal were collected, the crowns of all teeth were removed near the level of cementoenamel junction to obtain approximately 15 ±1 mm uniform root lengths. After instrumentaion with ProTaper Next files up to X4 (40/06), roots were randomly divided into 4 equal groups (n=15) according to the method of final irrigation activation. Group I: Conventional needle and syringe irrigation. Group II: Manual dynamic activation. Group III: passive ultrasonic irrigation. Group IV: photoactivated disinfection. Canal cleanliness was evaluated with SEM using different magnification (X350- X1000). Results: Group III had the best cleanliness of the root canal while Group I had the worst cleanliness, there were statistical significant differences between Group I versus Groups II and III and between Group III and Group IV (P ≤ 0.05). Regardless the irrigation activation method, the coronal level showed significantly less amount of smear layer and remaining debris than the apical level. Conclusions: None of the tested final irrigation activation methods resulted in completely clean canal wall.

COMPARATIVE STUDY OF ANTIBACTERIAL ACTIVITY OF PHOTOACTIVATED DISINFECTION WITH FOTOSAN AND STANDARD ENDODONTIC TREATMENT

Introduction: The purpose of endodontic treatment is to eliminate the bacterial infection in the root canal system and allow healing of apical periodontitis. Sometimes the anatomical complexity of the root canal system makes complete removal of bacteria almost impossible even if the conventional methods of chemo-mechanical debridement are performed strictly according to the protocol. So additional methods of root canal disinfection can be applied such as photoactivated disinfection (PAD). Purpose: The aim of our study was to compare the antibacterial activity of PAD with FotoSan, and conventional endodontic therapy in the treatment of infected root canals. Materials and methods: The study involved 36 teeth of patients who are diagnosed with pulp necrosis or with the periapical chronic periodontitis and require endodontic treatment and divided into two groups of 18 teeth each. The first microbiological sample was taken by placing a sterile paper point in the root canal, after endodontic access cavity preparation. All root canals are prepared by Protaper Universal rotary instruments (Maillefer Instruments SA, Ballaigues, Switzerland). In the first group, the disinfection of the root canals was made with photoactivated disinfection with FotoSan. In the second group was performed the endodontic treatment with the standard protocol of irrigation - 2.5% sodium hypochlorite solution and 17% EDTA. After that, the root canals are dried with sterile points, and a second microbiological sample is taken. Results: In all compared pairs, there was no significantly different effect regarding the number of microorganisms. Conclusions; The disinfection with NaOCl has the strongest antimicrobial effect in this study. Second place is occupied by PAD with FotoSan. We believe that the established antimicrobial effect of PAD make the method appropriate as complementary to routine endodontic treatment.

Blue Light Photodynamic Therapy With Curcumin and Riboflavin in the Management of Periodontitis: A Systematic Review.

Introduction: The aim of this article was to evaluate reports in the scientific literature that used antimicrobial photodynamic therapy (aPDT) with a blue light source and curcumin and riboflavin as photosensitizers in the management of periodontitis. Methods: The search was conducted in electronic databases, including PubMed, Web of Science, and Scopus, with the keywords "photodynamic therapy", "antimicrobial photodynamic therapy", "laser activated disinfection", "photoactivated disinfection", "light activated disinfection" "LED", "Periodontitis", "Curcumin", "Riboflavin", and "periodontitis" from 2012 to 2020. Results: After evaluating a total of 24 relevant articles, 13 articles were selected, full texts were read, and the data were extracted and placed in a table. Conclusion: Reviewing articles showed that curcumin as a photosensitizer activated by a blue wavelength is effective in the elimination of the various bacterial species involved in periodontal disease, and to the best of our knowledge, there is no study that has shown this substance does not reduce bacteria. According to the result of the articles, riboflavin as a photosensitizer activated by blue light can reduce bacteria that are involved in periodontitis, but other studies have reported that blue light alone can also reduce bacteria significantly. Therefore, more in-vitro and clinical trial studies are needed to give a more conclusive opinion on the effectiveness of riboflavin as a photosensitizer in the treatment of periodontitis.

Post-operative Pain after Photo-Active Disinfection (PAD) Supplemented Single Visit Root Canal Treatment in Teeth with Symptomatic Apical Periodontitis

Objective: To observe the incidence of post-operative pain after single-visit Non-Surgical Endodontic Therapy (NSET) in teeth with symptomatic apical periodontitis disinfected with Photo-Activated Disinfection (PAD). Methods: Single-rooted teeth (N=30) with pulp necrosis and symptomatic apical periodontitis were included. Subsequent to chemo mechanical preparation, the teeth were randomly distributed into two groups: group I (n=15) which received calcium hydroxide slurry as an intracanal medicament and group II (n=15) which received PAD and obturation in the same visit. Postoperative pain was recorded at 4, 24, 48 and72 hours using a visual analog pain scale. One-way analysis of variance post hoc Tukey test was used to compare the score. Results: There was a significant reduction in pain after instrumentation in Groups I and II. The pain reduction was more in group I as compared to group II at 4 hours. There was no statistically significant difference seen in both the groups at 24, 48 and 72 hours postoperatively. Conclusion: Application of PAD as an adjunct in single visit NSET has no noticeable difference in pain perception when compared with the use of calcium hydroxide interim dressing in two visits NSET.

Optimization of treatment and prevention of generalized periodontal diseases with the use of transgingival photoactived disinfection

The aim of the study is to develop protocols for the treatment and prevention of generalized periodontal disease using a nozzle that designed for transgingival photosensitizer activation.&#x0D; Methods. Analysis of available variants of irradiation nozzles for photoactivated disinfection. Circuit design and construction of authors’ irradiation nozzle for transgingival photosensitizer activation.&#x0D; Results. Based on the analysis of data, there was developed a nozzle design that allows treating periodontium areas within 4-6 teeth, evenly distributes the required power of laser radiation, and can be used in hard-to-reach areas of the oral cavity. Based on the above calculations, a nozzle for transgingival photosensitizer activation was created (jointly with Fotonika Plus, PE). To optimize the PAD procedure, there was created a protocol of transgingival photoactivated disinfection to be applied at the stage of professional oral hygiene, using the created irradiation nozzle NOU-9 of authors’ design, and diode 2 W laser LIKA-surgeon with a wavelength of 660 nm. The result is the accelerated procedure of transgingival photoactivated disinfection.&#x0D; Conclusions. The development of photoactivated disinfection technology allows supplementing the traditional treatment of generalized periodontal diseases. Studies of non-invasive, transgingival method of photosensitizer activation have recently become popular. This, in turn, carries a lower probability of cross-infection and less traumatization of periodontal tissues during the manipulation. The use of PAD cannot lead to resistance of the microflora in contrast to pharmacological antibacterial preparations. Carrying out PAD does not require any complex manual skills, the purchase of expensive equipment, provides an opportunity for widespread introduction of technology. The use of the therapeutic complex and protocols of PAD that were developed can significantly reduce the duration of the procedure, resulting in improved comfort for both the doctor and the patient. The NOU-9 irradiation nozzle allows reaching hard-to-reach areas of the oral cavity, distributing laser radiation efficiently and evenly on periodontal tissues. The LIKA-surgeon 2 W laser with a wavelength of 660 nm provides the operating parameters required to activate the photosensitizer. Due to low-intensity radiation, it is possible to enhance regenerative processes in the periodontium after traumatic intervention. Clinical studies on the antibacterial efficacy of the technology are ongoing

Radiological Appraisal of Biodentine and Pulpotec Individually or in Combination with Photo-activated Disinfection as Pulp-capping Cements in Mature Teeth

The aim of the study was to evaluate and compare radiographically, Pulpotec cement and Biodentine as direct pulp-capping agents in mature teeth, individually and in combination with photo-activated disinfection (PAD). In the present study, 80 mature teeth with deep occlusal caries were selected for direct pulp-capping procedure and randomly assigned to one of the four groups [Pulpotec (I), Biodentine (II), Pulpotec + PAD (III), and Biodentine + PAD (IV)] allocating 20 teeth to each group. Direct pulp capping and cavity disinfection were performed based on the group allotted followed by permanent restoration with composite. The teeth were evaluated radiographically (densitometric analysis) at intervals of 3, 6, and 12 months. The radiographic gray values obtained at follow-up periods for each group were subjected to two-way analysis of variance (ANOVA) with repeated measures. There was a significant improvement (p <0.0001) in the scores of all the groups at follow-ups as compared to the baseline. There was a significant difference between group I/group II with groups III and IV (p = 0.000) with group IV scoring highest at all follow-ups. However, the difference between groups I/II and groups III/IV was nonsignificant. Both, Biodentine and Pulpotec can be used for direct pulp capping of mature teeth. Furthermore, PAD prior to material application significantly improved the radiographical success of Biodentine and Pulpotec, with Biodentine showing better results than Pulpotec. Biodentine and Pulpotec demonstrated comparable success as a pulp-capping agent and PAD application exhibited a synergistic effect when used in conjunction with these materials.

Comparative evaluation of photoactivated disinfection and sonic irrigation as an adjunct to conventional irrigation on Enterococcus faecalis in root canals: An in vitro study

Objective: The aim of the in vitro study was to compare the antibacterial efficacy of photoactivated disinfection (PAD), sonic irrigation as an adjunct to conventional irrigation against Enterococcus faecalis in vitro.Materials and Methods: A total of 75 extracted teeth were selected and prepared followed by inoculation with strains of E. faecalis, and a preirrigation sample was collected using sterile paper points. These teeth were then divided randomly into three groups for irrigation: Group I (Conventional irrigation), Group II (PAD), and Group III (EndoActivator) followed by postirrigation sample collection using the sterile paper points. The samples were swabbed on blood agar plates and incubated followed by the calculation of colony-forming units (CFU's).Results: The results were statistically analyzed using the SPSS software version 18.0. On comparing the mean values among the groups, the reduction in the number of CFU's after the treatment protocol was highly significant for all groups (P < 0.001). With the preirrigation sample, there is a statistically significant difference in the values of Group I and Group II (P = 0.047). However, in case of postirrigation samples, there is nonsignificant difference between Group II and Group III.Conclusion: PAD using 940 nm diode laser and methylene blue and endoactivator were more effective than sodium hypochlorite (NaOCl) in reducing E. faecalis counts.

Disinfection of Root Canals with Laser-Activated Irrigation, Photoactivated Disinfection, and Combined Laser Techniques: An Ex Vivo Preliminary Study.

Objective: This study aimed to evaluate the efficacy of laser-activated irrigation using photon-induced photoacoustic streaming (PIPS®) and photoactivated disinfection (PAD) techniques and their combination to improve penetration and activation of toluidine blue in the endodontic space of teeth experimentally infected with Enterococcus faecalis. Materials and methods: Twenty-seven extracted single-root teeth were instrumented, sterilized, and infected with E. faecalis and divided into seven groups of three teeth each: Group A [sodium hypochlorite (NaClO) 5% hand irrigation], Group B [NaClO 5% hand irrigation+ethylenediaminetetraacetic acid (EDTA)+NaClO 5% activated by PIPS], Group C (EDTA+NaClO 5% activated by PIPS), Group D (toluidine blue activated by PAD), Group E (toluidine blue activated by PIPS and PAD), Group F (NaClO 5% hand irrigation+toluidine blue activated by PAD), and Group G (NaClO 5% hand irrigation+toluidine blue activated by PIPS and PAD). Finally, positive and negative group controls were prepared. The presence of biofilms after the treatments was assessed by the BioTimer assay. PIPS was performed with an Er:YAG laser (2940 nm, LightWalker, Fotona® d.o.o., Slovenia) at 20 mJ, 15 Hz, 0.3 W, and 50-μs pulse duration. PAD was performed with a 635 nm diode laser (Smart M, Lasotronix®, Poland) at 400 mW in continuous wave (CW). Results: When NaClO was used, significant decontamination (p ≤ 0.05) was obtained in all experimental groups with respect to the positive control, other than Group G. Irrigation with EDTA+NaClO activated by PIPS produced a higher level of decontamination than Group A (p ≤ 0.05). Significant results in reducing biofilm load compared with the control and Group A were observed when NaClO was coupled with toluidine blue activated by PAD (p ≤ 0.05). Conclusions: Disinfection of root canals can be obtained using a combination of different irrigants, photosensitizers, and activation protocols. EDTA+NaClO using the PIPS protocol and toluidine blue activated by PAD (both preceded by NaClO irrigation) can be considered effective tools. The possibility of replacing NaClO with toluidine blue, whatever the method of activation, should be further investigated.

Influence of Propolis, Ozone and Photodynamic therapy in root canal disinfection on resin bond strength to radicular dentin.

The aim of the present study was to assess post space disinfection using different irrigants and their effect on radicular dentin bond to SERC. Forty single rooted mandibular 2nd premolars were collected and disinfected. All samples were decoronated maintaining root length of 12 mm and embedded vertically in acrylic resin. Shaping of the canal was performed using reciprocating system. Canals were dried using paper points and obturated with gutta percha via lateral condensation. Peso-reamers were used to create post space up to 10 mm. The post space was irrigated with 1% NaOCl before being randomly allocated into four groups (n = 10) according to different methods of canal disinfection. Samples in group 1 were subjected to photoactivated disinfection (PAD), group 2 irrigated with ethanol based propolis group 3 disinfected using ozone and group 4 irrigated with 2.25 % NaOCl with 17 % EDTA and ECL. GFP was fitted using SERC. Each sample was cut into 1 mm from coronal, middle and apical and subjected to pushout bond strength (PBS) via universal testing machine. Fracture analysis were confirmed by stereomicroscope at 40x magnification. For comparison of means, Analysis of variance (ANOVA) and Tukey multiple comparison test was used maintaining the level of significance at p < 0.05. The highest PBS at all three levels were found in group 4, canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL. Whereas, the lowest PBS was observed in group 1. Inter group comparison, prosthetic space disinfected with propolis extract showed no significant difference to group 4 canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL at all three levels (p > 0.05). Intra group comparison in all experimental groups showed no significant difference was noted in coronal and middle thirds of group 1, group 2 and group 3 respectively (p > 0.05). 2.5 % NaOCl with EDTA and ECL treatment (group 4) remains the gold standard when used as a final canal irrigant. Propolis can be used as potential irrigant for canal disinfectant provided if the composition becomes standardized.

Single Sitting Revitalization of Nonvital Young Permanent Teeth

AbstractA 9-year-old child reported with chief complaint of broken teeth (11 and 21) and discolored tooth (21). Diagnosis of pulp necrosis with apical periodontitis with regard to 11 and 21 was made based on clinical and radiographic examination. The canals were irrigated with sodium hypochlorite and then dried with paper points. Disinfection of canals was done using photoactivated disinfection (PAD). Platelet-rich fibrin (PRF) was placed as scaffold in canals till the cementoenamel junction (CEJ). A 2-mm thick layer of white MTA was placed, followed by dual seal using glass–ionomer cement (GIC) and composite resin. Follow-up examination was done for 1 year. Clinical examination showed no pain, tenderness on percussion, and no mobility and improvement in color of teeth. Radiographic evaluation revealed continued thickening of the dentinal walls, root lengthening, regression of the periapical lesion, and partial apical closure. This report of pulp revascularization shows that disinfection with photodynamic therapy combined with PRF resulted in satisfactory root development in necrotic immature teeth.