Sandra Márcia Habitante

Effectiveness of Photodynamic Therapy Against Enterococcus faecalis, With and Without the Use of an Intracanal Optical Fiber: An In Vitro Study

BACKGROUND AND OBJECTIVE Photodynamic therapy (PDT) is a new technique introduced in endodontics that combines the action of a photosensitizer (dye) and a low intensity light source. Currently, there are no PDT studies evaluating the microbial disinfection of root canals in order to compare the effects of light delivery systems in the photosensitizer activation. The aim of this study was to evaluate the PDT effectiveness in reducing Enterococcus faecalis, with and without the aid of an intracanal optical fiber. METHODS Extracted single-rooted teeth were selected, instrumented, inoculated with E. faecalis and divided into six groups: one control group (untreated), one conventionally-treated group (1% NaOCl irrigation) and four PDT-treated groups. Irradiation (diode laser) was performed with (OF) or without an intracanal optical fiber (NOF) using two different irradiation times: 1 min and 30 sec (IT(90)) or 3 min (IT(180)). Samples were collected before and after testing procedures and CFU/mL was determined. RESULTS The greatest reduction of E. faecalis (99.99%) was achieved with irrigation with 1% NaOCl. PDT also significantly reduced E. faecalis in the following decreasing order: OF/IT(180), NOF/IT(180), OF/IT(90) and NOF/IT(90), with no significant statistical difference among the groups. CONCLUSIONS These results suggest that PDT was effective against E. faecalis, regardless of the use of an intracanal optical fiber.

Surface finishing of unused rotary endodontic instruments: a SEM study

During endodontic therapy, cleaning of root canals is performed using endodontic files and auxiliary chemical substances, and it is important that the endodontist be familiar with the instruments used in daily practice. This study evaluated, under scanning electron microscopy (SEM), the quality of the surface finishing of unused rotary endodontic instruments. Fifty sizes 20, 25 and 30 rotary files from different commercial brands (ProFile, Protaper, Race, Hero and K3 Endo) were removed directly from their packages and had their final 3 mm examined with a scanning electron microscope at x190 magnification with no previous preparation. The images were evaluated by 3 skillful, calibrated, blinded observers according to the following criteria: cutting edge, debris, grooves, microcavities, tip shape, tip position, scraping and transition angle. Data were recorded in worksheets designed for the study. Irregular edges were observed in 50-100% of the files. Except for ProFile, all commercial brands presented surface debris in 100% of samples. Only Race files showed no grooves or microcavities. K3 Endo files presented the best tip centralization. Excetp for ProTaper files, all commercial brands presented blunt-cutting edges in 100% of samples. All types of files presented surface scraping. K3 Endo files and Protaper had a high percentage of transition angle. Based on the evaluation criteria used in the present study, most samples presented a minimum of 2 alterations and a maximum of 7 alterations per instrument. Under the tested conditions, the quality of the surface finishing of the examined instruments was not as expected, given that no instrument was free of imperfections and most of them presented at least 2 and up to 7 types of surface defects. These results suggest that the manufacturing process and the packaging conditions of rotary endodontic instruments are far from ideal.

Effect of Chemical Substances in Removing Methylene Blue After Photodynamic Therapy in Root Canal Treatment

BACKGROUND AND OBJECTIVE The disadvantage of photodynamic therapy (PDT) is in the photosensitizing agents that may stain the tooth structure. There is no register of PDT studies evaluating protocols to minimize that concern. The present study evaluated the efficiency of chemical adjuncts in methylene blue dye (MB) removal after PDT. MATERIALS AND METHODS Forty single-rooted teeth, after root canal preparation, were filled with 0.01% MB for 5  min, and irradiated with diode laser 660  nm at 40  mW for 240  sec (total energy 9.6  J). The specimens were divided into four groups (n = 10), according to the chemical adjuncts used for dye removal: (a) 2.5% sodium hypochlorite (NaOCl); (b) 2.5% NaOCl + Endo-PTC cream; (c) 70% ethyl alcohol and (d) saline (control). The crowns were sectioned and fixed in a device. Photographs were taken before the PDT (T0), immediately after (T1) and upon dye removal (T2). The chromatic alterations were evaluated using Adobe Photoshop and K values were determined in four fixed points of each crown. RESULTS K values (dental staining) increased in all groups when comparing T0 and T1. The effectiveness of the tested adjuncts was, in decreasing order: G1 (-3.11) > G2 (-2.97) > G3 (-1.28) > G4 (-1.19), not observing significant statistical differences (p < 0.05) between G1 and G2 and also between G3 and G4. CONCLUSIONS Protocols to remove photosensitizing dyes should be applied after PDT in order to minimize dental stain. The protocols tested in this study by using 2.5% NaOCl, associated or not with Endo-PTC cream, were effective in avoiding tooth staining caused by MB during PDT.

Tooth Discoloration Induced by Endodontic Phenothiazine Dyes in Photodynamic Therapy

OBJECTIVE This study sought to assess if discoloration of tooth structures occurs after photodynamic therapy (PDT) and to determine the efficacy of a protocol to remove the photosensitizers. BACKGROUND DATA PDT has been used in root canal treatment to enhance cleaning and disinfection of the root canal system. PDT uses a low power laser in association with a dye as a photosensitizer. Photosensitizers can induce staining of the dental structures, resulting in an unaesthetic appearance. METHODS Forty teeth were randomly divided into four groups according to the photosensitizer used and pre-irradiation time: 0.01% methylene blue for 5 min (MB5); 0.01% methylene blue for 10 min (MB10); 0.01% toluidine blue for 5 min (TB5); and 0.01% toluidine blue for 10 min (TB10). Specimens were irradiated with a 660 nm diode laser with a 300 μm diameter optical fiber, at 40 mW power setting for 3 min. Immediately after, the photosensitizers were removed with Endo-PTC cream+2.5% sodium hypochlorite (NaOCl). The shade was measured by a Vita Easyshade spectrophotometer based on the CIELAB color system (L*a*b* values) at three different experimental times: before PDT (T0), immediately after PDT (T1), and after removal of the photosensitizer (T2). RESULTS The results showed a decrease in the averages of the L*a*b* coordinate values after PDT (T1) in all the groups, when compared with the number at T0, with a significant statistical difference in group MB10. After photosensitizer removal (T2), all the values of the coordinates increased with significant statistical differences (p<0.05) between T1 and T2 in L* and a*. CONCLUSIONS It can be concluded that both methylene blue and toluidine blue dyes cause tooth discoloration, and that Endo-PTC cream associated with 2.5% NaOCl effectively remove these dyes, regardless of the pre-irradiation time used for PDT.

Root surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats.

UNLABELLED BACKGROUND AIM:  The aim of this study was to evaluate, by radiographic and histomorphometric analyses, the effects of high-power diode laser irradiation on the root surfaces of delayed replanted rat teeth. MATERIAL AND METHODS   Maxillary right incisors were extracted from 60 Wistar rats and kept dry for 60 min. Subsequently, the root canals were prepared and filled with calcium hydroxide paste. According to the root surface treatment before the replantation, the teeth were assigned to four groups (n = 15): G1 (negative control) - no root surface treatment; G2 (positive control) - treated with 2% sodium fluoride solution; G3 - irradiated with a high-power diode laser (810 nm, continuous mode, 1.0 W, 30 s); and G4 - irradiated with a diode laser using the same parameters as those used for G3 but in pulsed mode. The rats were euthanized after 15, 30, and 60 days of replantation. The specimens were digitally radiographed and processed for histomorphometric analysis to determine the average root resorption areas and to evaluate the histological events. RESULTS   The percentage of root resorption was in the following order: G1 > G2 > G4 > G3. Both histomorphometric and radiographic analyses showed significantly lower means (P < 0.05) of the occurrence of root resorption in the irradiated groups (G3 and G4) when compared to the control groups (G1 and G2). Replacement resorption and ankylosis were observed in histological sections only after 30 and 60 days; however, such events were not observed in G3. CONCLUSION   Root surface treatments with high-powered diode laser irradiation prior to delayed replantation reduced the occurrence of external root resorption compared to no treatment or sodium fluoride treatment at up to 60 days.

Perda de corte da lima protaper quanto a esterilização e número de uso

Objetivo: Este estudo propoe-se avaliar a perda de corte do instrumento rotatorio ProTaper® em funcao do numero de uso e esterilizacao em autoclave. Metodo: Foram estudados 10 canais simulados de resina acrilica transparente com ângulo de curvatura de 45o, valendo-se de instrumentos Protaper® de numeracao S1, S2, F1, F2 e F3, substituindo o Sx pelas brocas de Largo #1. Os blocos foram pesados em balanca analitica digital, anotando-se o peso inicial. A seguir, houve o preparo com motor eletrico Endo Pro-Torque® da Driller com reverso automatico submetido ao ajuste e controle da velocidade em 350 rpm, torque de 1N, com engate para contra-ângulo modelo Kavo®, tomando-se o cuidado de padronizar o tempo de acao de cada instrumento em 3 minutos. Usou-se o creme de Endo-PTC durante o preparo do canal simulado e apos seu tempo de acao, lavava-se o canal com hipoclorito de sodio. Depois, o bloco era lavado com detergente neutro, seco com gaze, canal aspirado, seco com cone de papel absorvente, pesado, anotando-se o peso final. A cada uso as limas rotatorias eram limpas com gaze embebido em alcool e, posteriormente, lavadas com detergente neutro e secas tambem com gaze e levadas em envelope descartavel para processo de esterilizacao em autoclave com ciclo de 20 minutos. Resultados: Os instrumentos utilizados perderam a sua capacidade de corte em funcao do numero de uso. Conclusao: O instrumento perde a capacidade de corte em funcao do uso, e so a partir do se¬timo uso, o instrumento ProTaper® perde consideravelmente sua efetividade, recomendando-se seu descarte Aims: This investigation aims to evaluate the cutting loss and sterilization of rotary ProTaper® instrument for sterilization process in autoclave. Method: Were studied ten substrate resin simulated canals blocks numbered 1 to 10 with angle of 45o. Before and after instrumentation were used with ProTaper® files numbering S1, S2, F1, F2, F3, is substituting for the Sx Largo drills # 1. These blocks were weighted using an analytical digital scale model Mettler AJ 100 and following it were analyzed of the amount of resin removed in each sample were noted both initial and final weight. The instrumentation was made with Endo-Pro-Torque engine-driven Driller system with automatic reverse and speed control in 350 rpm, torque 1N using stop watch for standardize the 3 minutes time of each instrument. Cream Endo-PTC was used during instrumentation e after that, washing the canals with 5mL the distillate water with plastic syringe. The blocks were washed with detergent, dry with gauze, aspirated canal, dried with paper absorbent points, weighted and noted final weight. In each use the files were clean with gauze alcohol soaked and later washed with detergent and dried with gauze and put in recipient discard able for sterilization in autoclave Sercon model during 20 minutes. Results: The instruments used have lost the cutting ability in relation to the number of use. Conclusions: It?s concluded that occurred a loss of efficiency of the cutting instrument, however the instrument ProTaper loses its cutting ability in use only after the seventh use and thus it?s recommended its discard

Evaluation of a strategic practice demonstration method applied to endodontic laboratory classes

PURPOSE: To evaluate a strategic method of real time visual demonstration of the operatory procedures using an intraoral camera system and monitor videos, comparing them to those of conventional laboratory classes. METHODS: Fifty-two structured, multiple choice questionnaires were applied to undergraduate students of the 4th year (G1) and 3rd year (G2) submitted to the traditional and strategic teaching methods, respectively. These tests were also able to detect the main problems faced by the students during the training of this operatory phase. RESULTS: Students of both groups (G1- 30.8% and G2- 34.6%) considered the access cavity to be one of the most difficult phase of endodontic treatment. The results of the evaluation among the 3rd year students demonstrated that 23.1% graded the new method as excellent, 38.4% as very good and 38.5 % as good, whereas none of the students (0%) considered the method to be regular, bad or very bad. A minor accident occurrence (P<0.05) was reported by the 3rd year students (G1- 50% and G2- 34.6%). CONCLUSION: The new strategy was found to favor learning, reduce the incidence of errors and was appraised as efficient by the students.

Effects of diode laser irradiation and fibroblast growth factor on periodontal healing of replanted teeth after extended extra-oral dry time.

AIM The search for effective protocols to reduce the incidence of root resorption and allow periodontal ligament repair is still challenging, given the unpredictable outcome of late tooth replantation. The aim of this study was to assess the effects of both high-power diode laser irradiation (DL) and basic fibroblast growth factor (FGF) on the periodontal healing of replanted teeth after extended extra-oral dry time. METHODS Maxillary incisors of 50 male rats were extracted and assigned to three experimental and two control groups (n = 10). DL: root surfaces treated with DL (810 nm, continuous mode, 1.0 W, 30 s), FGF: topical application of FGF gel to the root surface and in the alveolar wound, DL + FGF: DL and topical application of FGF gel, C+: no treatment after extraction and immediate replantation and C-: no treatment after extraction and replantation after 60 min. In the experimental groups, the specimens were kept dry for 60 min, the pulps were removed and the canals were filled with calcium hydroxide paste prior to tooth replantation. The animals were euthanized after 60 days. The specimens were processed for radiographic, histological and immunohistochemical analyses. RESULTS The radiographic analysis showed fewer resorptive areas in DL + FGF (P < 0.05). The histological and immunohistochemical analyses showed that the DL group had lower mean values of ankylosis, replacement and inflammatory resorption when compared to C-, not differing statistically from C+. DL + FGF produced significantly more collagen fibers (type I and type III) than C-, not differing from C+ in the case of type I fibers (P < 0.05). CONCLUSIONS DL, with or without FGF, reduced the occurrence of external root resorption and ankylosis. Periodontal healing was favored and some fiber reinsertion occurred only when FGF was used.

Radiopacity of Mineral Trioxide Aggregate with and without Inclusion of Silver Nanoparticles

AIM The aim of this study was to investigate the inclusion of silver nanoparticles (Ag NPs) in the mineral trioxide aggregate (MTA) composition to know which changes will result in the radiopacity of the material. MATERIALS AND METHODS The experiment was performed according to the American National Standard Institute/American Dental Association specification no. 57/2000 and ISO 6876/2001. Five plates with five holes measuring 1 mm in depth and 5 mm in internal diameter were filled according to the different experimental groups as follows: white mineral trioxide aggregate (WMTA) + NP50 - W MTA with liquid Ag NP 50 ppm, WMTA + NP30 - W MTA with liquid Ag NP 30 ppm, WMTA + NP22 - W MTA with liquid Ag NP 22 ppm, WMTA + NPP - white MTA with liquid Ag NP and powder 1%, WMTA (control). After filling the plates, they were kept in an incubator at 37°C in relative humidity for setting. Each sample was positioned along an aluminum step-wedge placed above the Opteo digital sensor system. The image was divided into four quadrants, and three readings were made for each quadrant to render the average of each quadrant. The resulting data were submitted to Kruskal-Wallis and Dunns tests. RESULTS The results showed statistically significant differences between WMTA + NP30, WMTA + NP22, and WMTA + NPP interactions compared with WMTA (control) (p < 0.05). The radiopacity was in descending order: WMTA + NPP, WMTA + NP22, WMTA + NP30, MTA + NP50, and WMTA. CONCLUSION Silver NPs changed the radiopacity of WMTA, being more evident in WMTA + NP powder at 1% weight. CLINICAL SIGNIFICANCE The low radiopacity of MTA makes it difficult for any radiographic observation. The Ag NPs appear as an alternative, being an excellent radiopacifier as they have excellent antimicrobial property and relatively low toxicity.

Effect of nitric oxide inhibitor and donor substances on the infammatory process caused by endodontic irrigants

Nitric oxide (NO) has been considered a key molecule in inflammation Objective The aim of this study was to evaluate the effect of treatment with L-NAME and sodium nitroprussiate, substances that inhibit and release NO, respectively, on tissue tolerance to endodontic irrigants. Material and Methods The vital dye exudation method was used in a rat subcutaneous tissue model. Injections of 2% Evans blue were administered intravenously into the dorsal penial vein of 14 male rats (200-300 g). The NO inhibitor and donor substances were injected into the subcutaneous tissue in the dorsal region, forming two groups of animals: G1 was inoculated with L-NAME and G2 with sodium nitroprussiate. Both groups received injections of the test endodontic irrigants: acetic acid, 15% citric acid, 17% EDTA-T and saline (control). After 30 min, analysis of the extravasated dye was performed by light absorption spectrophotometry (620 nm). Results There was statistically significant difference (p<0.05) between groups 1 and 2 for all irrigants. L-NAME produced a less intense inflammatory reaction and nitroprussiate intensified this process. Conclusion Independently of the administration of NO inhibitors and donors, EDTA-T produced the highest irritating potential in vital tissue among the tested irrigating solutions.