Avaliação da acurácia de quatro localizadores apicais durante o retratamento endodôntico / Evaluate the accuracy of four electronic apex locators during endodontic retreatment

Este estudo teve como objetivo avaliar a acurácia de quatro localizadores apicais eletrônicos durante o retratamento endodôntico. Quarenta pré-molares unirradiculares com apenas um canal, ápice completamente formado, foram divididos em quatro grupos e analisados: Grupo 1: Root ZX ll. Grupo 2: Mini Root. Grupo 3: Propex ll e Grupo 4: Mini Apex. Todos os elementos foram padronizados no comprimento de 22 mm, instrumentados com limas Wave One Primary (25.08), obturados e armazenados. Após um mês, foram desobturados com limas reciprocantes Wave One Primary (25.08) e, em seguida, montados em blocos de esponja vegetal, embebida em solução de cloreto de sódio a 0,9%. A acurácia eletrônica de cada elemento foi realizada, utilizando-se uma lima manual do tipo K#20, até que a mesma fosse ultrapassada pelo forame e recuada até o comprimento real do dente, onde, então, as medidas de cada elemento eram anotadas. Todas as medidas obtidas de cada grupo passaram por análise estatística. Não houve diferença estatisticamente significante entre os localizadores apicais eletrônicos analisados, quando utilizados durante o retratamento endodôntico, sendo possível concluir que, os quatro modelos de localizadores apicais analisados mostraram-se eficientes durante o retratamento endodôntico, dentro dos limites estabelecidos, não havendo diferença entre eles.

This study aimed to evaluate the accuracy of four electronic apex locators during endodontic retreatment. Forty single-rooted premolars, with a root canal, with fully formed apex, were divided into four groups and analyzed: Group 1: Root ZX II. Group 2: Mini Root. Group 3: Propex II and Group 4: Mini Apex. All elements have been standardized in the length of 22 mm, instrumented with Wave One Primary (25.08) files, sealed and stored. After a month, the desobturation with reciprocating Wave One Primaty (25.08) files off and then assembled into blocks vegetable sponge, soaked in 0.9% sodium chloride solution. Electronic accuracy of each element was performed using a manual file type K#20, until it was overtaken by the foramen and retracted to the actual length of the tooth, which then measures each element were noted. All measurements obtained from each group passed by statistical analysis. There was no statistically significant difference between the electronic apex locators analyzed when used during endodontic retreatment it is possible to conclude that the four models analyzed apex locators were effective during endodontic retreatment wirhin the established timits, there is no difference between them.

Antigenicity of primary endodontic infection against macrophages by the levels of PGE(2) production.

INTRODUCTION: Root canal contents are potent stimuli for proinflammatory cytokines involved in apical periodontitis. This study investigated target gram-negative bacterial species and endotoxins in primary endodontic infection with apical periodontitis, determined their antigenicity against macrophages through the levels of PGE(2), and evaluated their relationship with clinical findings. METHODS: Samples were taken from 21 root canals with primary infection and apical periodontitis by using paper points. Polymerase chain reaction (16S rDNA) was used for bacterial detection and limulus amebocyte lysate assay for endotoxin measurement. Levels of prostaglandin E2 (PGE(2)) were measured by enzyme-linked immunosorbent assay (Duoset Kit; R&D, Minneapolis, MN). RESULTS: Prevotella nigrescens (13/21), Fusobacterium nucleatum (6/21), and Porphyromonas endodontalis (6/21) were the most frequently observed species. A positive association was found between F. nucleatum and P. endodontalis (P < .05). A correlation was found between the number of gram-negative bacterial species and the levels of endotoxins, such as PGE(2) (P < .05). Higher levels of endotoxin were detected in teeth with exudation, whereas elevated levels of PGE(2) were found in teeth with tenderness to percussion and pain on palpation. CONCLUSIONS: Our findings imply an additive effect between the number of gram-negative bacterial species involved in endodontic infection regarding the induction of proinflammatory cytokine by macrophage cells. Moreover, teeth with clinical symptomatology were related to higher levels of endotoxins and PGE(2) secretion.

Influence of curvature location along an artificial canal on cyclic fatigue of a rotary nickel-titanium endodontic instrument.

OBJECTIVES: This study evaluated the effects of curvature location along an artificial canal on cyclic fatigue (CF) of an Mtwo rotary instrument, verifying the number of cycles to fatigue fracture (NCF) and morphologic characteristics of the fractured instruments. STUDY DESIGN: CF testing of instruments was performed in artificial canals with curvature radii of 10 mm and arc lengths of 11 mm. Mtwo rotary instruments size 40, 0.04 taper were used in 2 groups (n = 10): group A, curvature positioned on middle part; group B, apical curvature. All instruments were rotated until fracture. The number of cycles to failure was registered. Data were analyzed by independent sample t test. Fractured surfaces and the helical shafts of the instruments were analyzed by scanning electron microscopy. RESULTS: NCF for groups A and B had significant statistic differences (P < .05). The highest values were found in the group where the curvature was positioned on the apical part of the canal. No plastic deformation was observed on the helical shafts. CONCLUSIONS: The number of cycles to fracture of the Mtwo instruments increased when the arc was changed from the middle to the apical part of the canal. The morphologic characteristics of the fractured surfaces were of the ductile type.

Antigenic activity of bacterial endodontic contents from primary root canal infection with periapical lesions against macrophage in the release of interleukin-1beta and tumor necrosis factor alpha.

INTRODUCTION: Periradicular tissue chronic stimulation by endotoxin may cause apical periodontitis. This study investigated the microbial profile and the levels of endotoxin found in primary root canal infection with apical periodontitis, determined their antigenicity against macrophages through the levels of interleukin (IL)-1beta and tumor necrosis factor alpha (TNF-alpha), and evaluated their relationship with clinical and radiographic findings. METHODS: Samples were taken from 21 root canals with primary endodontic infection and apical periodontitis with paper points. PCR technique (16S rDNA) was used for the detection of the target bacteria. Limulus Amebocyte Lysate (LAL) was used to measure endotoxin. The amounts of IL-1ss/ TNF-alpha in macrophages supernatants were measured by enzyme-linked immunosorbent assay--Duoset-kit (ELISA). RESULTS: Prevotella nigrescens (13/21), Porphyromonas endodontalis (6/21), and Treponema socranskii (6/21) were the most frequently detected gram-negative bacterial species. The presence of the sinus tract (2/21) was related to the detection of Filifactor alocis (p < 0.05), whereas a tooth with a radiolucent area > or = 2 mm was related to the detection of Treponema denticola. A correlation was found between the number of gram-negative bacteria and the levels of IL-1beta/TNF-alpha (p < 0.05). Increased levels of endotoxin were followed by TNF-alpha release (p < 0.05). Higher levels of IL-1beta (p < 0.05) and endotoxin contents were related to the larger size of the radiolucent area. CONCLUSION: The antigenicity of the endodontic contents is not only related to the amount of endotoxin found in the root canal but also to the number of different species of gram-negative bacteria involved in the infection. Moreover, a larger size (> or = 2 mm) of the radiolucent area was related to IL-1beta and endotoxin.

Geometria e acabamento superficial de espaçadores endodônticos digitais de aço inoxidável e de NiTi / Geometry and surface finishing of stainless steel and Ni-Ti finger spreader

No presente trabalho, avaliou-se as características geométricas e o acabamento superficial de espaçadores endodônticos digitais de aço inoxidável e de níquel-titânio identificados pelas letras A, B, C e D, fabricados pela Dentsply-Maillefer, Suiça. Os resultados obtidos indicaram que os espaçadores de aço inoxidável e de níquel-titânio apresentaram: vértices das pontas com formas diferentes; diâmetros, conicidades e comprimentos semelhantes; segmentos cônicos das hastes metálicas com comprimentos e acabamentos superficiais diferentes.