Ana Paula Martins Gomes

Clinical Comparison of the Effectiveness of Single-file Reciprocating Systems and Rotary Systems for Removal of Endotoxins and Cultivable Bacteria from Primarily Infected Root Canals

INTRODUCTION This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria from primarily infected root canals. METHODS Forty-eight primarily infected root canals were selected and randomly divided into 4 groups: WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) (n = 12); Reciproc (VDW, Munich, Germany) (n = 12), ProTaper (Dentsply Maillefer) (n = 12), and Mtwo (VDW) (n = 12). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts. RESULTS In the baseline samples (ie, samples collected before chemomechanical preparation), endotoxins and cultivable bacteria were recovered from 100% of the root canal samples. No differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems (ie, WaveOne [95.15%] and Reciproc [96.21%]) and with rotary systems (ie, ProTaper [97.98%] and Mtwo [96.34%]) (P < .05). Both single-file reciprocating systems (ie, WaveOne [99.45%] and Reciproc [99.93%]) and rotary systems (ProTaper [99.85%] and Mtwo [99.41%]) were effective in reducing the cultivable bacteria (all P < .05). Moreover, the culture analysis revealed no differences in bacterial load reduction (P > .05). CONCLUSIONS Both single-file reciprocating systems (ie, WaveOne and Reciproc instruments) and rotary systems (ie, ProTaper and Mtwo instruments) showed similar effectiveness in reducing endotoxins and cultivable bacteria from primarily infected root canals, but they were not able to eliminate them from all root canals analyzed.

In vitro evaluation of apical sealing in root apex treated with demineralization agents and retrofiled with mineral trioxide aggregate through marginal dye leakage.

The purpose of this study was to evaluate the apical seal in root apex treated with different demineralization agents and retrofilled with mineral trioxide aggregate (MTA) using marginal dye leakage. Fifty-six, human single-rooted teeth were instrumented, filled, resected and had retrofilling cavities prepared with ultrasonic tips. Demineralizing agents were applied before the apical cavities were retrofilled with Pro Root MTA. The specimens were assigned to 4 groups (n=14), as follows: group 1 (no demineralizing agent); group 2 (35% phosphoric acid, for 15 s); group 3 (17% EDTA solution, pH 7, for 3 min); and group 4 (24% EDTA gel, pH 7, for 4 min). The extension of dye (2% rhodamine B, at 37 degrees C, for 24 h) penetration was measured in millimeters using a stereomicroscope. Results were statistically analyzed by ANOVA and Tukeys test at 5% significance level. Among the experimental groups, the least extension of dye penetration was observed in group 1 (1.89 mm), followed by groups 2 (2.18 mm), 4 (2.54 mm) and 3 (2.64 mm). No statistically significant differences (p<0.05) were found in marginal microleakage among groups 1, 2 and 4 and groups 2, 3 and 4. Based on the results obtained in this study, it may be concluded that the application of demineralizing agents cannot be recommended when MTA is used in periradicular surgeries.

Clinical Influence of Different Intracanal Medications on Th1-type and Th2-type Cytokine Responses in Apical Periodontitis

INTRODUCTION This clinical study assessed the influence of different intracanal medications on Th1-type and Th2-type cytokine responses in apical periodontitis and monitored the levels of bacteria from primarily infection during endodontic procedures. METHODS Thirty primarily infected teeth were randomly divided into 3 groups according to the medication selected: chlorhexidine (CHX), 2% CHX gel; Ca(OH)2/SSL, Ca(OH)2 + SSL; and Ca(OH)2/CHX, Ca(OH)2 + 2% CHX gel (all, n = 10). Bacterial sample was collected from root canals, and the interstitial fluid was sampled from lesions. Culture techniques were used to determine bacterial counts (colony-forming units/mL). Th1 (tumor necrosis factor-α, interferon-γ, and interleukin [IL]-2) and Th2 cytokines (IL-4, IL-5, and IL-13) were measured by enzyme-linked immunosorbent assay. RESULTS All intracanal medication protocols were effective in reducing the bacterial load from root canals (all P < .05) and lowering the levels of Th1-type cytokines in apical lesions (all P < .05), with no differences between them (P > .05). Both Ca(OH)2 treatment protocols significantly increased the levels of Th2-type cytokines (P < .05), with no differences between them (P > .05). Thus, chlorhexidine medication showed the lowest effectiveness in increasing the levels of Th2-type cytokine. After treatment, regardless of the type of medication, the linear regression analysis indicated the down-regulation of Th2-type cytokines by Th1-type cytokines. CONCLUSIONS All intracanal medication protocols were effective in reducing bacterial load and lowering the levels of Th1-type cytokines. Thus, the use of Ca(OH)2 medications contributed to the increase in the Th2-type cytokine response in apical periodontitis.

The effect of endodontic materials on the optical density of dyes used in marginal leakage studies

The aim of this study was to determine the effect of the exposure of different endodontic materials to different dye solutions by evaluating the optical density of the dye solutions. Seventy-five plastic tubes were filled with one of the following materials: AH Plus, Sealapex, Portland cement, MTA (Angelus and Pro Root) and fifteen control plastic tubes were not. Each specimen of material and control was immersed in a container with 1 ml of each dye solution. A 0.1 ml-dye solution aliquote was removed before immersion and after 12, 24, 48 and 72 hours of each specimen immersion to record its optical density (OD) in a spectrophotometer. Statistical analysis was performed with ANOVA and Tukey tests (5%). No significant difference was found among any of the solution OD values for AH Plus cement. Portland cement promoted different OD values after 12 hours of immersion. MTA-Angelus cement presented different OD values only for 2% rhodamine B and the MTA-Pro Root cement presented different OD values in all 2% rhodamine B samples. Sealapex cement promoted a reduction in the India Ink OD values. Dye evaluation through OD seems to be an interesting method to select the best dye solution to use in a given marginal leakage study.

A comparative study of the physical properties of conventional and Grander-modified adhesive systems

Purpose: The objective of this study was to evaluate the influence of the Grander technology in reducing the surface tension and contact angle of a self-etch adhesive system. Methods: Distilled water and Xeno III self-etch adhesive system (Dentsply) were modified by physical contact with the Flexible unit Grander system to revitalize water, for 48 hours, resulting in four groups: Group 1 - Xeno III under normal conditions; Group 2 - Xeno III modified by Grander; Group 3 - distilled water under normal conditions; Group 4 - distilled water system modified by the Grander system;. Surface tension and contact angle (dentin substrate and titanium plate) of the adhesive system and water in normal and Grander-modified conditions was measured with a goniometer. Data were analyzed by ANOVA and Tukey test (5%). Results: Grander technology reduced the surface tension of water but not of the adhesive system Xeno III. The contact angle property of the adhesive ystem was not affected. Conclusion: Grander technology did not interfere with the surface tension and contact angle physical properties of the Xeno III self-etch adhesive system.

Avalilação dos erros radiográficos cometidos por alunos de graduação durante o tratamento endodôntico

Introduction: The aim of this study is to evaluate the radiographic errors performed by undergraduate students during the endodontic treatment. Methods: A total of 260 periapical radiographs were divided in these: groups initial radiography, length tooth, try-in of gutta-percha point, corroborative of the lateral condensation e final radiography. The radiographs were obtained employing the same kind of film (E-speed, Kodak) and of X-Ray units (50KV, 7,5mA), with a 0,8-second exposure time, and they were processed by visual method. With help of a magnifying glass and a viewbox, three examiners analyzed the radiographs and registered errors related to technique and processing. Results: The results showed that 57,70% of the radiographs analyzed exhibited some kind of errors (technique errors or processing). There were not significant differences in the number of the errors in the different phases of endodontic treatment. Conclusion: The highest frequency of errors was seen in radiograph processing (stains, presence of splines and inadequate radiographic density). DESCRIPTORS: Radiography dentalQuality controlDiagnosis.

Does supplemental photodynamic therapy optimize the disinfection of bacteria and endotoxins in one-visit and two-visit root canal therapy? A randomized clinical trial

AIM To evaluate the effectiveness of supplemental photodynamic therapy (PDT) in optimizing the removal of bacteria and endotoxins from primarily infected root canals after one-visit and two-visit treatments. METHODOLOGY Twenty-four primarily infected root canals with apical periodontitis were selected and randomly divided into one-visit (n=12) and two-visit treatment groups (n=12). Chemo-mechanical preparation (CMP) was performed by using the single-file reciprocating technique+2.5% NaOCL and a final rinse with 17% EDTA. The photosensitizer agent (methylene blue 0.1mg/mL) was applied to root canals for 60s before application of laser with a potency of 60mW and energy density of 129J/cm2 for 120s after CMP in the one-visit treatment and after 14-day inter-appointment medication with Ca(OH)2+Saline solution (SSL) in the two-visit treatment. Samples were collected before and after root canal procedures. Endotoxins were quantified by chromogenic limulus amebocyte lysate assay. Culture techniques were used to determine bacterial colony-forming unit counts. RESULTS Bacteria and endotoxins were detected in 100% of the initial samples, with median values of 1.97×105 CFU/mL and 24.983EU/mL, respectively. The CMP using single-file reciprocating technique was effective in the reduction of bacteria and endotoxins (All, p<0.05). The supplemental PDT was effective in reducing bacterial load in the one-visit (p<0.05) but not in the two-visit treatment after use of Ca(OH)2 medication for 14days (p>0.05). In the two-visit group, after 14days of inter-appointment medication with Ca(OH)2, a significant reduction in the median levels of endotoxins was found in comparison to CMP alone (from 1.041 to 0.094EU/mL) (p<0.05). Despite the type of treatment, the supplemental PDT was not effective against endotoxins (p>0.05). CONCLUSIONS The photodynamic therapy optimized the disinfection of bacteria from root canals in one-visit but not for two visit treatment modality with the accomplishment of calcium hydroxide medication. Despite the type of treatment, the supplemental PDT was not effective against endotoxins.

Avaliação do contato de dois materiais retrobturadores no pH de corantes tamponados e não tamponados

O objetivo deste trabalho foi avaliar o pH das solucoes corantes de azul de metileno 2% tamponada e nao tamponada, rodamina B 2% tamponada e nao tamponada, antes e apos a imersao de dois materiais retrobturadores por diferentes periodos de tempo. As solucoes corantes, sem a imersao dos especimes, foram analisadas nos periodos de tempo de 0, 12, 24, 48 e 72 horas. Foram preparados oitenta cilindros de cimento Sealer 26 e oitenta de cimento de Portland, os quais foram imersos em 0,7 ml de cada uma das solucoes corantes e avaliados apos os periodos de tempo de 12, 24, 48 e 72 horas. Os dados de pH foram obtidos utilizando um pHmetro e analisados por meio de estatistica descritiva e ANOVA (3 fatores). Concluiu-se que a imersao dos materiais endodonticos promoveu alteracoes no pH das solucoes corantes nos diferentes periodos de tempo de analise, sendo que as solucoes nao tamponadas apresentaram maior variacao. Dentre as solucoes corantes analisadas, a rodamina B 2% tamponada apresentou comportamento mais estavel de pH ate o periodo de tempo de 48 horas.

Expressão do gene p53 no carcinoma bucal: revista da literatura. Influência da esterilização em estufa sobre cones de papel absorvente para endodontia

A busca por marcadores biologicos que auxiliem no diagnostico, prognostico e tratamento das neoplasias e intensa. O diagnostico precoce e importantissimo para a sobrevida do paciente e o p53 tem sido amplamente estudado. O gene p53 esta localizado no cromossomo 17p13.1 e sua mutacao e a alteracao mais comum nas neoplasias humanas. A maioria das mutacoes ocorre em celulas somaticas, porem formas herdadas tambem foram encontradas. Neste artigo e feita uma breve revista sobre a carcinogenese bucal e a expressao de p53.