Influence of different sized files on the accuracy of two electronic apex locators.

The aim of this study was to evaluate the impact of different file sizes on the accuracy of two electronic apex locators (EALs). Thirty extracted human single-rooted permanent mandibular incisors were used. A #10 K-file was inserted in the root canal until its end could be observed (using a light microscope) through the apical foramen. One millimetre was subtracted to establish working length (WL). Electronic readings were performed using MiniApex Locator or Root ZX II, from #10 K-file to #130 K-file. Statistical analysis was performed by two-way anova and Tukey test (P ≤ 0.05). From #60 to #130 K-file, observed differences were noted between the values obtained with both EALs and WL (P ≤ 0.05). The MiniApex Locator showed increased means when measurements were made with #50 to #70 and with #120 (P = 0.008) and #130 (P = 0.005) K-files. File sizes influenced the accuracy of EALs - the greater the instrumentation size, the higher mean differences compared to WL.

Influence of embedding media on the assessment of electronic apex locators.

Third-generation electronic apex locators for root canal length determination are very reliable and are not subject to interference from the contents of the canals. This study compared the effectiveness of different embedding media for in vitro assessment of electronic apex locators. The tooth lengths of 30 extracted human mandibular central incisors were measured by introducing a size 15 K-file fitted with a silicone stop into the canal until its tip appeared through the apical foramen; the distance between the tip and stop was measured. The teeth were placed in cylindrical polyethylene tubes filled with different embedding media (1% agar, gelatin, alginate, saline, and flower sponge soaked in saline), and electronic reading was performed with the Root ZX device. Data were statistically assessed by the analysis of variance (ANOVA) and Tukey tests at a significance level of 5%. Despite the lack of statistically significant difference among the media, the flower sponge was the only medium in which the file surpassed the apex in some measurements.

Evaluation of apical cavity preparation with a new type of ultrasonic diamond tip.

This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.

Efficacy of the NaviTip FX irrigation needle in removing calcium hydroxide from root canal.

OBJECTIVE: To evaluate the effectiveness of the NaviTip FX, brush-covered irrigation needle, in removing calcium hydroxide from the root canal. STUDY DESIGN: Thirty single-rooted teeth were randomly divided into three groups: A - irrigation with a hypodermic needle inserted as far as possible without binding and activation with #30 K-type file; B - Irrigation with a hypodermic needle without activation; C - irrigation with NaviTip FX needle. Sodium hypoclorite 1% was used in irrigation. The root canals were examined trough scanning electron microscopy. Calcium hydroxide removal was recorded at 1, 5, and 10mm from the working length (WL) and the data were analysed using one-way ANOVA test (p<0.05). RESULTS: NaviTip FX and hypodermic needle activated with #30K-type file showed lower score at 10 and 5mm with no significant difference between them. Comparison within groups did not show significant differences. All groups showed significantly better smear layer removal at 5 and 10 mm from the WL. CONCLUSION: The apical third (1mm) of the root canal was found to be the most critical site for Ca(OH)2 removal. Key words:Calcium hydroxide, irrigation, scanning electron microscope, NaviTip FX.

Physical properties and interfacial adaptation of three epoxy resin-based sealers.

INTRODUCTION: The aim of the study was to evaluate the radiopacity, solubility, flow, film thickness, setting time, and adaptation to the root canal walls of 3 epoxy resin-based sealers: AH Plus, Acroseal, and Adseal. METHODS: Physical tests were performed following American National Standards Institute/American Dental Association's requirements. For interfacial adaptation analysis, 30 maxillary canines were shaped by using ProTaper instruments. The specimens were divided into 3 groups (n = 10): group 1, AH Plus; group 2, Acroseal; and group 3, Adseal. The sealers were mixed with rhodamine B dye, and the canals were filled by using the lateral compaction technique. The percentage of gaps and voids area was calculated at 2, 4, and 6 mm levels from the apex. Statistical evaluation was performed by using analysis of variance for physical analysis and nonparametric Kruskal-Wallis and Dunn tests for interfacial adaptation (P < .05). RESULTS: No statistical differences were found for adaptation, percentage of voids, solubility, flow, and film thickness among the sealers (P > .05). AH Plus was significantly more radiopaque (P < .05). For the setting time, there were statistical differences among all the studied sealers (P < .05). CONCLUSIONS: AH Plus, Acroseal, and Adseal presented similar root canal adaptation, solubility, flow, and film thickness. Statistical differences were found for radiopacity and setting time (P < .05).

Evaluation of the flow rate of 3 endodontic sealers: Sealer 26, AH Plus, and MTA Obtura.

OBJECTIVE: The aim of this study was to evaluate the flow rate of 3 endodontic sealers: Sealer 26, AH Plus, and MTA Obtura. STUDY DESIGN: According to the method proposed by the American Dental Association (ADA specification no. 57), the sealers were placed between 2 glass slabs under a weight of 120 g. The diameters of the formed discs were measured with a digital paquimeter. The test was repeated 5 times for each sealer. RESULTS: The results were expressed as arithmetic means, and the statistical analysis was performed through Turkey test. AH Plus showed significantly superior flow rate compared with Sealer 26 and MTA Obtura. There was no statistically significant difference between flow rates presented by Sealer 26 and MTA Obtura. CONCLUSION: Within the limitations of this in vitro study, it was concluded that all of the the endodontic sealers tested presented greater flow than the minimum recommended in the ADA 57 specification.

Antimicrobial effects of calcium hydroxide and chlorhexidine on Enterococcus faecalis.

INTRODUCTION: Endodontic treatment is commonly based on nonspecific elimination of intraradicular microorganisms. Although some authors prefer single-visit root canal operations for endodontic treatment, several studies have shown the importance of intracanal medication between sessions to kill microorganisms that biomechanical preparations alone cannot achieve. The purpose of this study was to evaluate the efficacy of calcium hydroxide Ca(OH)(2) and chlorhexidine gel on the elimination of intratubular Enterococcus faecalis. METHODS: Human uniradicular teeth contaminated with E. faecalis were treated with Ca(OH)(2), 2% chlorhexidine gel, Ca(OH)(2) plus 2% chlorhexidine gel, or saline (0.9% NaCl) as a negative control. Samples obtained at a depth of 0 to 100 mum and 100 to 200 mum from these root canal preparations were analyzed for bacterial load by counting the number of colony-forming units (CFUs) and bacterial viability using fluorescence microscopy. RESULTS: A significant decrease in the number of CFUs and the percentage of viable E. faecalis was observed after treatment with either Ca(OH)(2) or chlorhexidine when compared with the control group. Additionally, chlorhexidine gel had a significantly higher antimicrobial efficacy as measured by the number of CFUs and the percentage of viable cells than Ca(OH)(2). No differences were observed between the antimicrobial properties of chlorhexidine gel with and without the addition of Ca(OH)(2). CONCLUSION: Both Ca(OH)(2) and chlorhexidine have antimicrobial effects on E. faecalis. Chlorhexidine had increased antimicrobial activity when compared with Ca(OH)(2.) Ca(OH)(2) combined with chlorhexidine showed similar antimicrobial activity to chlorhexidine alone.

Heat-killed Enterococcus faecalis alters nitric oxide and CXCL12 production but not CXCL8 and CCL3 production by cultured human dental pulp fibroblasts.

INTRODUCTION: Fibroblasts are the most abundant cells in dental pulp. To investigate their capacity to produce the chemokines CCL3, CXCL8, and CXCL12 as well as nitric oxide (NO), we evaluated the production of these mediators in supernatants of cultured human dental pulp fibroblasts (HDPF) stimulated by heat-killed Enterococcus faecalis (HKEF). METHODS: Primary cultures of HDPF were stimulated with medium alone or HKEF (1:1, 10:1, or 100:1 bacteria:fibroblast) for 1, 6, and 24 hours. Chemokines and NO were assessed through enzyme-linked immunosorbent assay and Griess reaction, respectively. Statistical analysis was performed by using analysis of variance and Tukey post test. RESULTS: CCL3 was not detected, whereas constitutive CXCL8 was not affected. Production of CXCL12 was increased at 1 and 6 hours, and NO was increased at the concentration of 1:1 bacteria:fibroblast at 24 hours. Viability and proliferation assays did not reveal cell number differences. CONCLUSIONS: These findings demonstrate that heat-killed E. faecalis is able to increase production of CXCL12 and NO by HDPF.

Evaluation of precision of length determination with 3 electronic apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30.

OBJECTIVE: The aim of this study was to perform a comparative analysis of precision of 3 apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30. STUDY DESIGN: Forty extracted single-rooted human teeth were selected. After endodontic access, measurement of the anatomical tooth length was visually performed by insertion of a K-file size 10 until its tip could be observed at the apical foramen with aid of a light microscope at 8x magnification. Following, the teeth were placed in a plastic box with alginate and electronically measured with the 3 apex locators at 1-mm short of the apical foramen. RESULTS: The results revealed a precision rate of 97.5% for Root ZX, 95% for Elements Diagnostic Unit and Apex Locator, and 92.5% for RomiAPEX D-30, with no statistically significant difference between them (chi-square test, P > .05). CONCLUSION: The results confirm that all these electronic devices can accurately determine the root canal length within 1 mm from the apical constriction.

Comparação dos debris produzidos após instrumentação pelos sistemas waveone e protaper em canais mesiais de molares inferiores / Comparison of hard-tissue debris produced by wave one and protaper instruments on mesial roots of mandibular molars.

Objetivo: O preparo biomecânico tem como objetivo promover a limpeza, antissepsia e modelagem do sistema de canais radiculares favorecendo a eliminação de bactérias e seus produtos, tecido pulpar vivo ou degenerado, dentina, e debris dentinários contaminados, criando um espaço adequado para a obturação do sistema de canais radiculares. O presente estudo teve como objetivo comparar os sistemas Protaper e Waveone na produção de debris dentinários no interior do canal e a compactação de debris na região de istmos em raízes mesiais de molares inferiores. Material e Métodos: Foram selecionados 20 raízes mesiais de molares inferiores de dentes humanos. A instrumentação dos canais foi realizada com o sistema Protaper e WaveOne de acordo as especificações do fabricante. O volume de irrigante total empregado foi de 21 e 16 ml respectivamente. Em seguida, os dentes foram seccionados em planos transversais a 2,4 e 6mm do ápice e analisadas mediante estereomicroscopia com magnificação de 40 X. Qualquer material presente no interior do canal ou itsmo foi quantificado como debris. Resultados: Não houve diferença estatisticamente significante (p<0.05) na acumulação de debris em todas as secções. Protaper obteve maior porcentagem de limpeza de istmos em todas as secções, Conclusão: Os resultados sugerem que o volume de irrigação parece não ter influência na remoção de debris do interior do canal, mas sim na limpeza de istmos.

Aim: Biomechanical preparation aims to promote cleaning and shaping of the root canal system, bacteria and their products, live or degenerated pulp tissue, dentin, and contaminated dentin debris, creating adequate space for the obturation of the root canal system. The present study aimed to compare the Protaper and Waveone systems on the production of dentinal debris inside the canal and compression of debris in the area of isthmuses in mesial roots of mandibular molars. Material and Methods:Twenty mesial roots of mandibular molars of human teeth where selected. The instrumentation of the canals was performed with Protaper and WaveOne system according to the manufacturer's specifications. The total volume of irrigant employed was 21 and 16 ml respectively. Then, the teeth were sectioned in transverse sections at 2, 4 and 6mm from the apex and analyzed by stereomicroscopy with a magnification of 40 X. Any material present within the canal or isthmus was quantified as debris. Results: No statistically significant differences (p <0.05) in the accumulation of debris in all sections were found. Protaper had a higher percentage of cleaning isthmuses in all sections, Conclusions: The results suggest that the volume of irrigation seems to have no influence on the removal of debris from the interior of the canals, although, showed betteristhmus cleaning.

Use of MTA and intracanal post reinforcement in a horizontally fractured tooth: a case report.

Root fracture is one of the consequences of dental traumatisms. The possibility of saving the fractured tooth depends on the level of the fracture and also on pulp vitality. This case report describes the use of MTA in association to an intracanal post to reinforce a maxillary central incisor with horizontal root fracture in its cervical third.

Regeneração óssea em alvéolos de ratos após enxerto de osso bovino inorgânico medular e biocerâmica sintética densa / Alveolar bone regeneration in rats after grafting of anorganic bovine bone and thick synthetic bioceramic

Introdução: é incerto se o uso de biomateriais em cirurgiasparendodônticas é capaz de facilitar ou induziro processo de regeneração óssea. Esse estudo analisou,comparativamente, os efeitos do preenchimento de alvéolosde ratos com osso bovino inorgânico medular euma biocerâmica sintética densa no processo de regeneraçãoóssea. Material: Quarenta e oito ratos albinosWistar foram distribuídos, aleatoriamente, em três grupos,que, após a extração dentária, tiveram os alvéolos preenchidosda seguinte forma: GI (n = 12) coágulo (controle);GII (n = 18) osso bovino inorgânico medular; GIII (n = 18)biocerâmica sintética densa. As amostras foram obtidasem 7, 15 e 30 dias pós-cirurgia. Foram realizadas análisesmicroscópicas quantitativas do infiltrado inflamató-rio, densidade fibroblástica, densidade angioblástica eneoformação óssea. Os dados foram submetidos ao testede Kruskal-Wallis (α < 0,05) para detectar diferenças entreos grupos no mesmo intervalo de tempo. Resultados:apesar de terem sido detectadas algumas diferenças entreos grupos experimentais e o controle para infiltrado inflamatórioe densidade angioblástica em 07 dias, e formaçãoóssea em 15 dias, no período de 30 dias o processo de reparofoi semelhante para todos os grupos. Conclusões:não houve diferença entre os dois materiais empregados,os quais não atrasaram o processo de regeneração óssea,e, se usados em cirurgias parendodônticas, podem atuarcomo materiais osteocondutores e osteopreenchedoresnos grandes defeitos ósseos.