Abstract Clinical decision-making tends to be based on what clinicians have been taught during undergraduate and graduate programs. The aim of the present study was to assess the clinical approach and to identify the factors that influence the decision-making for dental pulp exposure among graduate students and coordinating professors in endodontics programs offered at Brazilian universities. The study used a mail-out survey developed in the Qualtrics platform, based on seven clinical reports in which dental pulp exposure was evidenced. Descriptive statistics showing vital pulp therapy (VPT) and root canal treatment (RCT) were calculated for each clinical report. Data on the participants’ (n = 113) profile and variables related to clinical and radiographic characteristics of the cases were evaluated as to their potential to affect decision-making and analyzed by logistic regression (p < 0.05). VPT was likely to be indicated in cases of patients with immature teeth (OR = 0.017; 95%CI = 0.004 -0.073). RCT indications were related to the presence of symptoms (OR = 5.326; 95%CI = 1.429–19.852) and old age (OR = 21.057; 95%CI=6.809–65.120). In pulp exposure secondary to trauma, time of pulp exposure was significantly associated with RCT indication (OR=3.267; 95%CI=1.332–8.012). The present study demonstrated that patient age, root development, and symptom features were the main factors affecting participants’ decision-making.

Abstract Introduction Coronavirus disease 19 (COVID-19) is potentially the greatest global public health crisis of this century. This disease emerged as an outbreak of pneumonia of unknown cause in Wuhan, the capital city of the Hubei province in China, in December 2019. Otolaryngologists, head and neck surgeons and dentists are at an increased risk of occupational disease. Objective The present review summarizes currently published evidence of Covid-19 epidemiology, clinical characteristics, treatment and prevention. No proven effective treatments for this disease currently exist. Data Synthesis COVID-19 started from a zoonotic transmission event associated with a large seafood market that also traded in live wild animals, and it soon became clear that efficient person-to-person transmission was also occurring. Symptoms are varied, and not all patients develop all of them. Conclusion Social distancing seems to have been successful in several places in the world. However, this recommendation alone is not enough to contain the disease, and it is not a long-term solution. Large-scale testing by health professionals of representative samples of the population may give an estimate of the progression of the disease. Different treatments are under test and bring hope of a cure to the population. However, no current treatments (April 27, 2020) have been proven to be the key to success in the treatment of patients with COVID-19. Planetary health is a useful concept to understand the current drivers of this pandemic and to draw a roadmap for science and healthcare that may guide actions to fight economic depression and ensure a healthy recovery.

Resumo Um dos requisistos para a aplicação clínica de materiais endodônticos é apresentar comportamento biológico satisfatório. Neste estudo, as respostas do tecido conjuntivo a cimentos endodônticos à base de silicone (GuttaFlow 2), resina epóxica (AH Plus) e óxido de zinco e eugenol (Endofill) foram comparadas. Doze ratos Wistar tiveram tubos de polietileno (4 em cada animal) contendo um dos materiais e tubos vazios (controle negativo) implantados no tecido conjuntivo subcutâneo. Os tubos foram randomicamente posicionados pelo menos 2 cm distantes entre si e da espinha dorsal do animal. Amostras de tecido contendo os implantes foram processadas para análise histológica após 7 e 60 dias (n=6 animais por período). Células inflamatórias, condensação fibrosa e formação de abscesso foram classificadas em escores de acordo com sua intensidade. O teste Friedman, seguido por post hoc de Dunn, foi empregado para comparar os cimentos. O teste de Mann-Witney U foi empregado para verificar diferenças entre os períodos experimentais em cada grupo (p<0,05). Após 7 dias, a maior parte dos parâmetros histológicos não mostrou diferenças estatísticas entre os grupos. O cimento Endofill promoveu escores mais altos que os outros materiais para a variável células gigantes (p<0,05), além de apresentar um maior número de amostras com formação de abscesso. O GuttaFlow 2 tendeu a apresentar infiltrado inflamatório menos intenso comparado aos outros materiais. Após 60 dias, não houve diferenças estatisticamente significantes entre os grupos na maioria dos parâmetros avaliados. Entretanto, observou-se que o EndoFill apresentou escores mais altos para os macrófagos em comparação ao controle (p<0,05) e que o GuttaFlow 2 apresentou tendência a escores mais baixos que os demais materiais para as variáveis neutrófilos e abscesso. O GuttaFlow 2 apresentou propriedades biológicas apropriadas e pode ser considerado adequado para a prática clínica.

Abstract Satisfactory biological behavior is a necessary requirement for clinical application of endodontic materials. In this study, the connective tissue responses to silicone (GuttaFlow 2), epoxy resin (AH Plus) and zinc oxide and eugenol (Endofill) based sealers were compared. Twelve Wistar rats had polyethylene tubes (four per animal) containing one of the tested sealers and empty tubes (negative control) implanted in their subcutaneous tissue. The tubes were randomly placed 2 cm from the spine and at least 2 cm apart from one another. Tissue samples with implants were processed for histological analysis after 7 or 60 days (n=6 animals per period). Inflammatory cells, fibrous condensation and abscess were scored according to their intensity. Friedman, followed by Dunn's post hoc, was used to compare sealers. Differences between the two experimental periods were verified using Mann-Witney U test (p<0.05). At 7 days, most of the histological parameters showed no significant differences amongst groups. Endofill group scored higher than the others for giant cells (o<0.05) and promoted a greater number of samples presenting abscess formation. GuttaFlow 2 tended to show a less intense inflammatory infiltrate compared to the other materials. At 60 days, there were no significant differences between groups in most of the histological parameters evaluated. However, it was observed that Endofill scored higher for macrophages (p<0.05) compared to the control group, and GuttaFlow 2 tended to present lower scores than the others for neutrophils and abscess. GuttaFlow 2 showed proper biological behavior and should be considered adequate for clinical practice.

Abstract The present study aims to verify the effect of ozone gas (OZY® System) and high frequency electric pulse (Endox® System) systems on human root canals previously contaminated with Escherichia colilipopolysaccharide (LPS). Fifty single-rooted teeth had their dental crowns removed and root lengths standardized to 16 mm. The root canals were prepared up to #60 hand K-files and sterilized using gamma radiation with cobalt 60. The specimens were divided into the following five groups (n = 10) based on the disinfection protocol used: OZY® System, one 120-second-pulse (OZY 1p); OZY® System, four 24-second-pulses (OZY 4p); and Endox® System (ENDOX). Contaminated and non-contaminated canals were exposed only to apyrogenic water and used as positive (C+) and negative (C-) controls, respectively. LPS (O55:B55) was administered in all root canals except those belonging to group C-. After performing disinfection, LPS samples were collected from the canals using apyrogenic paper tips. Limulus Amoebocyte Lysate (LAL) was used to quantify the LPS levels, and the data obtained was analyzed using one-way ANOVA. The disinfection protocols used were unable to reduce the LPS levels significantly (p = 0.019). The use of ozone gas and high frequency electric pulses was not effective in eliminating LPS from the root canals.

Resumo: O objetivo deste estudo foi avaliar a capacidade de dissolução tecidual de diferentes soluções irrigadoras associadas ou não à agitação ultrassônica. Noventa fragmentos de polpa bovina (n=10 por grupo) foram pesados e em seguida colocados individualmente em tubos tipo Eppendorf contendo os seguintes irrigantes: G1- hipoclorito de sódio (NaOCl) a 2,5%; G2- NaOCl a 2,5% + agitação ultrassônica (US); G3- NaOCl a 2,5% + cetramida (CTR) a 0,2%; G4- NaOCl a 2,5% + CTR a 0,2% + US; G5- 400 ppm Sterilox (SX); G6- SX + US; G7- CTR a 0,2%; G8- CTR a 0,2% + US; G9- solução salina. Dois observadores cegados em relação aos grupos experimentais avaliaram as amostras continuamente durante as primeiras 4 h e depois a cada hora pelas próximas 12 h. A velocidade de dissolução foi calculada dividindo o peso inicial da polpa (mg) pelo período de tempo até sua dissolução completa (min). Os dados foram comparados por ANOVA e teste post hoc de Tukey com nível de significância de 5%. Os grupos G1 a G4 dissolveram os fragmentos de polpa completamente e G2 foi significativamente mais rápido do que os outros. Os grupos G5 a G9 não apresentaram atividade de dissolução. Em conclusão, apenas grupos contendo NaOCl foram capazes de dissolver tecido pulpar, o que foi melhorado pela agitação ultrassônica, mas não alterado quando CTR a 0,2% foi associada. Esta solução isolada e o Sterilox não mostraram nenhuma capacidade de dissolução, independentemente da utilização do ultrassom.

Abstract: The aim of this study was to evaluate the tissue dissolution ability of different irrigating solutions associated or not to ultrasonic agitation. Ninety bovine pulp fragments (n=10 per group) were weighed and then placed individually in Eppendorf test tubes containing the following irrigants: G1- 2.5% sodium hypochlorite (NaOCl); G2- 2.5% NaOCl + ultrasonic agitation (US); G3- 2.5% NaOCl + 0.2% cetrimide (CTR); G4- 2.5% NaOCl + 0.2% CTR + US; G5- 400 ppm Sterilox (SX); G6- SX + US; G7- 0.2% CTR; G8- 0.2% CTR + US; G9- saline solution. Two blinded observers assessed the samples continuously for the first 4 h, and then every hour for the next 12 h. Dissolution speed was calculated by dividing the initial pulp weight (mg) by the period of time until complete dissolution (min). Data were compared by ANOVA and Tukey post hoc test with a 5% significance level. G1 to G4 dissolved pulp fragments completely and G2 was significantly faster than the other groups. G5 to G9 did not exhibit dissolving activity. In conclusion, only groups containing NaOCl were capable of pulp tissue dissolution, which was enhanced by ultrasonic agitation, but did not alter when 0.2% cetrimide was associated. This isolated solution and Sterilox showed no dissolving capacity, regardless the use of ultrasound.

Este estudo realizou uma avaliação histológica do efeito das soluções irrigadoras Sterilox 400 ppm e hipoclorito de sódio (NaOCl) a 2% e 5%, com e sem a terapia fotodinâmica (PAD), na endodontia em sessão única de dentes de cães associados a lesões periapicais (APs). Dez cães foram divididos de forma randomizada em dois grupos (n=5): com e sem PAD, e os canais radiculares em quatro subgrupos, de acordo com a solução irrigadora utilizada: SX (Sterilox 400 ppm), SH2 (NaOCl 2%), SH5 (NaOCl 5%) e SS (solução salina) como controle positivo. Cento e trinta e quatro canais foram abertos e deixados expostos ao meio oral por 14 dias e depois selados por 60 dias para a indução de APs. Na sequência, os canais foram tratados de acordo com cada protocolo de desinfecção proposto e obturados na mesma sessão. Após 120 dias, os cães foram mortos e os eventos inflamatórios periapicais foram avaliados em microscopia óptica. Os dados qualitativos foram analisados estatisticamente pelos testes Kruskal-Wallis e Mann-Whitney (α=0,05). A PAD, quando empregada após o preparo químico-mecânico, não promoveu diferenças significativas nos escores para inflamação apical (p>0,05). As soluções irrigadoras SX, SH2 e SH5 sem PAD apresentaram diferenças estatísticas do grupo SS (p<0,05) que apresentou os maiores escores para inflamação apical. A PAD não apresentou efeito adicional na endodontia em sessão única dos canais com necrose pulpar associados a lesão apical e a solução irrigadora Sterilox 400 ppm pode ser considerada uma alternativa ao NaOCl na terapia endodôntica.

This study aimed to evaluate histologically the effect of irrigation with 400 ppm Sterilox, 2% and 5% sodium hypochlorite (NaOCl), with and without photo-activated therapy (PAD), in a single-visit root canal treatment of dog's teeth with apical periodontitis (AP). Ten dogs were randomly divided into two groups (n=5): with and without PAD, and the root canals into four subgroups, according to the irrigating solution: SX (400 ppm Sterilox), SH2 (2% NaOCl), SH5 (5% NaOCl) and SS (saline solution) as positive control. A total of 134 root canals were opened and left exposed to the oral environment for 14 days and then sealed for 60 days for AP induction. Then, root canals were treated according to each proposed disinfecting protocol and filled in the same session. After 120 days, the dogs were euthanized and the periapical inflammatory events were evaluated under light microscopy. Qualitative data were submitted to Kruskal-Wallis and Mann-Whitney tests (α=0.05). PAD did not produce significant differences in the scores for apical inflammation when used after chemo-mechanical preparation (p>0.05). The irrigating solutions SX, SH2 and SH5 without PAD were statistically different from SS (p<0.05) that presented the greatest scores for apical inflammation. PAD did not show any additional effect for the treatment of root canals with pulp necrosis and AP in a single visit and 400 ppm Sterilox may be considered an alternative to NaOCl in root canal treatment.

The present study aimed to determine the feasibility of using bovine teeth as a suitable alternative for human teeth, in experiments involving in vitro endotoxin contamination. Twenty bovine central incisors and 20 human single-root premolars had their dental crowns removed and root lengths set at 16 mm. Root canals were prepared up to #60 K-file size and sterilized with cobalt-60 gamma irradiation (20 kGy, 6 h). The teeth were randomly divided into four groups: G1-bovine teeth (bovine negative control, n = 10), G2-human teeth (human negative control, n = 10), G3-bovine teeth, inoculated withEscherichia coli (055:B55) LPS, and G4-human teeth inoculated with E. coli LPS. The G1 and G2 groups were exposed to apyrogenic water. After the teeth had been incubated at 37 °C and atmospheric humidity for 24 h, the samples of solutions in the main canals were collected with apyrogenic absorbent paper tips. LPS levels were quantified using Limulus Amebocyte Lysate assay. The data obtained were statistically analyzed using one-way ANOVA, with a significance level of 5%. A high amount of endotoxin was detected in the inoculated human teeth (G4) when compared to the sterilized teeth (G2), as well as in the inoculated bovine teeth (G3) when compared to the inoculated human teeth (G4). However, there was no statistical difference between bovine teeth before and after the E. coli endotoxin inoculation. Therefore, under the mentioned experimental conditions, the use of bovine teeth should not be a choice for laboratory research on endotoxin contamination.

O objetivo deste estudo foi detectar reabsorção radicular inflamatória apical (RRIA) associada à lesão periapical utilizando tomografia computadorizada de feixe cônico (TCFC) e microscopia eletrônica de varredura (MEV). Este estudo clínico avaliou RRIA em 88 ápices radiculares de 52 dentes permanentes de 14 pacientes, extraídos por diferentes motivos. Os pacientes foram submetidos a uma entrevista clínica, revisão da história médica/dental, exames clínicos e de imagem para o plano de tratamento. Todos os dentes selecionados apresentaram condição não restaurável devido à extensa perda de estrutura dental associada a lesões cariosas, e infecção do canal radicular associada a lesões periapicais. TCFC foram obtidas dos pacientes com o objetivo de diagnosticar as alterações periapicais que se mostraram complexas ou duvidosas. Dois examinadores avaliaram a presença ou ausência de RRIA. Os ápices foram também analisados por MEV. O teste do qui-quadrado foi usado para comparar os métodos de detecção de RRIA. O nível de significância foi estabelecido em 5%. RRIA associada à infecção do canal radicular e periodontite apical foi encontrada em 61,4% dos casos estudados usando MEV, e pelo menos metade dos casos utilizando TCFC. A análise microscópica continua a ser o padrão frente a métodos de imagens para a identificação de RRIA.

The aim of this study was to detect apical inflammatory root resorption (AIRR) associated with periapical lesion using cone beam computed tomography (CBCT) and scanning electronic microscopy (SEM). This clinical study evaluated AIRR in 88 root apexes, from 52 permanent teeth of 14 patients, extracted for different reasons. The patients were submitted to a clinical interview, review of dental/medical histories and clinical/imaging examinations for treatment planning. All selected teeth showed unrestorable condition because of the extensive coronal breakdown due to carious lesions, and root canal infection associated with periapical lesions. CBCT images were obtained from the patients with the aim of diagnosing the periapical diseases which showed complex or doubtful conditions. Two examiners assessed the presence or absence of AIRR. Apices were also analyzed under SEM. Chi-square test was used to compare the imaging methods for detection of AIRR. The level of statistical significance was set at 5%. AIRR associated with root canal infection and apical periodontitis was found in 61.4% of the cases studied by using SEM, and at least half of the cases by CBCT. The microscopic analysis remains as a reference standard against the imaging method to identify AIRR.

Tendo em vista que a instrumentação do forame apical tem sido sugerida para a limpeza e desinfecção do canal cementário, a seleção do calibre do instrumento e a posição do forame apical representam passos desafiantes. Este estudo analisou a influência que a saída lateral do forame apical e o calibre do instrumento podem exercer na instrumentação do canal cementário. Trinta e quatro incisivos centrais superiores foram divididos em dois grupos: Grupo 1 (n=17), sem preparo cervical, e Grupo 2 (n=17), com preparo cervical com brocas LA Axxess. Limas K com aumentos de diâmetro foram progressivamente inseridas no canal até ajustar no forame apical e as pontas ficarem visíveis e foram fixadas com adesivo de etil cianoacrilato. Os conjuntos raízes/limas foram seccionados transversalmente a 5 mm aquém do ápice. Os ápices foram examinados por microscopia eletrônica de varredura com aumento de 140x e imagens digitais foram capturadas. Os dados foram examinados estatisticamente pelo teste t de Student e teste exato de Fischer com nível de significância de 5%. A microscopia eletrônica de varredura mostrou que 19 (56%) dos forames apicais saíram lateralmente em relação ao ápice radicular, enquanto que 15 (44%) coincidiram com ele. Dificuldade significantemente maior para chegar ao forame apical foi observada no Grupo 2. Os resultados sugerem que quanto mais calibroso for o instrumento foraminal, mais difícil poderá ser a instrumentação do forame apical em canais cementários que apresentam saída lateral.

Since instrumentation of the apical foramen has been suggested for cleaning and disinfection of the cemental canal, selection of the file size and position of the apical foramen have challenging steps. This study analyzed the influence of apical foramen lateral opening and file size can exert on cemental canal instrumentation. Thirty-four human maxillary central incisors were divided in two groups: Group 1 (n=17), without flaring, and Group 2 (n=17), with flaring with LA Axxess burs. K-files of increasing diameters were progressively inserted into the canal until binding at the apical foramen was achieved and tips were visible and bonded with ethyl cyanoacrylate adhesive. Roots/files set were cross-sectioned 5 mm from the apex. Apices were examined by scanning electron microscopy at ×140 and digital images were captured. Data were analyzed statistically by Student’s t test and Fisher’s exact test at 5% significance level. SEM micrographs showed that 19 (56%) apical foramina emerged laterally to the root apex, whereas 15 (44%) coincided with it. Significantly more difficulty to reach the apical foramen was noted in Group 2. Results suggest that the larger the foraminal file size, the more difficult the apical foramen instrumentation may be in laterally emerged cemental canals.

OBJECTIVE: The presence of periapical radiolucency has been used as a criterion for endodontic treatment failure. However, in addition to the inherent limitations of radiographic examinations, radiographic interpretations are extremely subjective. Thus, this study investigated the effect of partial analysis of root filling quality and periapical status on retreatment decisions by general dentists. MATERIAL AND METHODS: Twelve digitalized periapical radiographs were analyzed by 10 observers. The study was conducted at three time points at 1-week intervals. Radiographs edited with the Adobe Photoshop CS4 software were analyzed at three time points: first, only root filling quality was analyzed; second, only the periapical areas of the teeth under study were visualized; finally, observers analyzed the unedited radiographic image. Spearman ’s coefficient was used to analyze the correlations between the scores assigned when the periapical area was not visible and when the unedited radiograph was analyzed, as well as between the scores assigned when root fillings where not visible and when the unedited radiograph was analyzed. Sensitivity, specificity, positive and negative predictive values between partial images and unedited radiographs were also used to analyze retreatment decisions. The level of significance was set at 5%. RESULTS: The visualization of the root filling on the unedited radiograph affected the interpretation of the periapical status and the technical quality of the fillings has a greater influence on the general dentist’s decision to prescribe endodontic retreatment than the periapical condition. CONCLUSION: In order to make endodontic diagnosis, radiographic interpretation process should not only emphasize technical aspects, but also consider biological factors.

Intracanal medication in pulpectomy therapy is used between appointments with the objective of reducing pain and inflammatory processes in pulp and periapical tissues. Propolis has been known as a natural antibiotic and has been subject of medical and dental research due to its therapeutic properties such as antibiotic, analgesic and anti-inflammatory effects. OBJECTIVE: The aim was to carry out an in vivo evaluation of the periapical tissue response to propolis paste when used as an intracanal medication in the teeth of dogs after pulpectomy. MATERIAL AND METHODS: 72 dog's incisors were selected for the experiment. After biomechanical preparation the root canal was filled with a corticosteroid-antibiotic preparation, experimental propolis paste, non-medicament (negative control) or non-pulpectomy at all (positive control). The medications were left inside the root canal for 7, 14 or 28 days. At the end of the experimental period histological sections were prepared and all laboratories processes for Harris hematoxylin and eosin staining was proceeded followed by the analysis using an optical microscope. Sections were classified according to a score representing the inflammatory events observed: the presence of polymorphonuclear neutrophils, polymorphonuclear eosinophils, lymphocytes and plasma cells, macrophages and/or giant cells, fibrous condensation and abscesses. RESULTS: There were statistically significant differences between the tissue reactions caused by the two substances being tested, after different experimental periods, with the periapical tissue that was in contact with propolis paste exhibiting fewer inflammatory reactions in comparison to corticosteroid-antibiotic preparation. CONCLUSIONS: The low tissue responses from propolis paste suggest that this material could be considered as an option for root canal medication after pulpectomy.

OBJECTIVE: The objective of this work was to evaluate, using radiographic images, the behavior of four materials used to repair root perforations in dogs' teeth. Material and METHODS: Second and third premolars of 6 dogs were used. The 48 teeth were randomly divided into 4 groups (n=12) and the perforations were sealed with one of the following materials: MTA, AH Plus, Vitremer and gutta-percha. Dogs were submitted to general anesthesia, teeth were radiographed and pulp was accessed. Perforations were done, at the maximum curve of the pulp floor, sealed and the accessed coronal cavity was filled with glass ionomer cement (Vidrion R). After 90 days, the dogs were sacrificed and the last x-ray image was taken. Images were analyzed for the presence/absence of periodontal lesions at the perforation region. Data were analyzed statistically by chi-square test at 5% significance level. RESULTS: There were no statistically significant differences (p>0.05) among AH Plus, Vitremer and gutta-percha groups. MTA produced the smallest number of periodontal lesions (p<0.05). CONCLUSIONS: It may be concluded that none of the tested materials was able to preserve the integrity of the periodontal tissues in the furcation region, and the use of MTA resulted in the least formation of adjacent periodontal bone lesions revealed by the radiographic comparisons.

OBJECTIVE: This study tested rat connective tissue response to RealSeal, RealSeal primer or AH Plus after 7, 15, 30, 60 and 90 days of implantation. MATERIAL AND METHODS: Thirty Wistar rats had subcutaneous sockets created on their back and received four implants each of polyethylene tubes containing one of the materials tested according to the groups: AH (AH Plus Sealer); RS (RealSeal Sealer); RP (RealSeal Primer); CG (control group - empty tube). After histological processing, sections were analyzed to identify the presence of neutrophils, lymphocytes and plasma cells, eosinophils, macrophages and giant cells, as well as fibrous capsule and abscesses, by an examiner using light microscope. Kruskal-Wallis and multiple-comparisons test were used for statistical analysis. Significance level was set at 5%. RESULTS: Lymphoplasmacytic infiltrate scores significantly higher than those of the control group were observed at 14 and 60 days in AH group, and at 90 days in RS group (p<0.05). There were no differences in terms of presence of macrophages, giant cells, eosinophils, neutrophils or fibrosis. AH Plus group scored higher for abscesses at 7 days than after any other period (p=0.031). RP group scored higher for lymphoplasmacytic infiltrate at 14 days than at 90 days (p=0.04). CONCLUSION: The main contribution of this study was to demonstrate that issues involved with tissue tolerance of a Resilon-containing sealer, RealSeal Sealer, cannot be attributed to its primer content.

OBJETIVO: Avaliar a capacidade de dissolução de tecido pulpar bovino com o uso da terapia fotodinâmica. METODOLOGIA: Vinte fragmentos de polpas bovinas foram pesados e distribuídos randomicamente em quatro grupos (n=5) de acordo com os seguintes protocolos de limpeza: G1 - água destilada (controle negativo), G2 - hipoclorito de sódio 1% (controle positivo), G3 - terapia fotodinâmica, G4 - hipoclorito de sódio 1% + terapia fotodinâmica. A observação dos eventos de dissolução foi realizada por dois observadores, cegados quanto aos grupos experimentais, com lupa de 2x de aumento, que registravam o tempo em minutos até a completa dissolução de tecido. O tempo total de observação foi de 2 horas. O cálculo da taxa de dissolução foi feito dividindo o peso do fragmento pelo tempo de dissolução (mg/min). RESULTADOS: Somente o grupo 2 (NaOCl 1%) foi capaz de promover dissolução completa do tecido pulpar, tendo como média de dissolução 1,26 mg/min. CONCLUSÃO: Apenas o hipoclorito de sódio foi capaz de dissolver os fragmentos de tecido pulpar bovino e a terapia fotodinâmica não mostrou capacidade de dissolução tecidual.

PURPOSE: To evaluate the bovine pulp tissue dissolution ability of photodynamic therapy. METHIDS: Twenty pieces of bovine pulp tissue were weighed and divided randomly into four groups (n=5), according to the cleaning protocol: G1 - distilled water (negative control), G2 - sodium hypochlorite 1% (positive control), G3 - photodynamic therapy, G4 - sodium hypochlorite 1% + photodynamic therapy. The observation of the events of dissolution was performed by two observers blinded in relation to the test using 2x magnification, recording time in minutes until complete tissue dissolution. The total observation time was 2 hours. The dissolution rate was calculated dividing the weight of the fragment pulp (mg) by the time of dissolution (mg/min). RESULTS: Only group 2 (NaOCl) was able to promote complete dissolution of pulp tissue. In the other groups there was no occurrence of complete dissolution of the samples. The mean dissolution time for samples from group 2 (NaOCl) was 1.26 mg/min. CONCLUSION: Only the sodium hypochlorite was able to dissolve the fragments of bovine pulp tissue and photodynamic therapy does not show ability to dissolve tissue.