Spectrophotometric analysis of microleakage in the fine curved canals found in the mesial roots of mandibular molars

Johnson, William T.; Zakariasen, Kenneth L.

doi:10.1016/0030-4220(83)90013-0

Cited by 19 publications

(9 citation statements)

References 32 publications

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“…The present study found similar rates of dentin removal compared to previous studies 4,[9][10][11][12][13][14][15]24 .…”

Section: Discussionsupporting

confidence: 87%

“…Despite the advantages, when excessive, the enlargement may cause accidents that may affect success, such as perforation or weakening of the furcal wall, especially in lower molars mesial roots 11,19 . Several methods may be used to evaluate the cervical preparation, such as resin blocks 20,21 , scanning electron microscopy 18 , X-rays 4 and computed tomography 22,23 .…”

Section: Discussionmentioning

confidence: 99%

“…The first rotating instruments developed for cervical preflaring were Gates-Glidden (GG) drills 1 , with a GG tip diameter # 2 of 0.70 mm, considered safe for lower molars mesial canals [9][10][11] . On the other hand, as they were made of stainless steel and had limited flexibility, their use leads to risks especially in the lower molars mesial root, as its excessive enlargement may lead to wear of lateral perforation of the root, named "Strip Perforation" 10,11 .…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, as they were made of stainless steel and had limited flexibility, their use leads to risks especially in the lower molars mesial root, as its excessive enlargement may lead to wear of lateral perforation of the root, named "Strip Perforation" 10,11 . This accident may affect the treatment prognosis since it may reduce the treatment success rates [12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

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The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

Pinto

Marceliano-Alves

Lins

et al. 2016

Rev. odontol. UNESP

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ResumoIntrodução: O preparo cervical é uma etapa importante da instrumentação do sistema de canais, mas pode levar ao alargamento excessivo ou rasgo da raiz. Objetivo: Avaliar, em tomografia computadorizada cone beam, da espessura remanescente de dentina cervical da raiz mesial de molares inferiores, após o preparo com diferentes técnicas: Gates-Glidden (ordem crescente); Gates-Glidden (ordem decrescente); LA Axxess e Easy Pro-Design. Material e método: Foram selecionadas 40 raízes mesiais de molares inferiores, que foram escaneadas em tomógrafo cone beam antes e após o preparo. Das imagens tomográficas foram obtidos cinco cortes com intervalo de 1 mm a partir da furca e, então, mensurada a variação da espessura entre o canal radicular até a porção externa da raiz em software de análise. Resultado: Avaliação dos diferentes níveis demonstraram ausência de significância dentro do mesmo grupo para o grupo das Gates-Glidden. Por outro lado, foi notada diferença para LA Axxess (p=0,002) e para Easy Pro-Design (p=0,005). Na avaliação entre os grupos, foi observada diferença em todos os níveis, sobretudo, para Gates-Glidden na ordem crescente (ANOVA e Tukey). Conclusão: Considerando as limitações desse estudo, concluiu-se que o protocolo que apresentou maior desgaste da área de perigo cervical foi o da Gates-Glidden em ordem crescente, sendo que os demais grupos foram equivalentes (p>0,05).Descritores: Instrumentos odontológicos; preparo de canal radicular; tomografia computadorizada de feixe cônico. AbstractIntroduction: Cervical preflaring is an important step of the canal system instrumentation, but can lead to excessive enlargement or root perforation. Objective: Evaluate the remaining dentin thickness in the mandibular molars of mesial roots using cone beam computed tomography: Gates-Glidden (crown-down); Gates-Glidden (step-back); LA Axxess and Easy Pro-Design. Material and method: Were selected 40 lower molars mesial roots, which were scanned in a cone beam CT scanner before and after preparation. Were obtained five sections of the CT images with an interval of 1 mm from the furcation, and measured the thickness variation between the root canal to the root external portion in analysis software. Result: The evaluation of the different levels showed no significance within the same group for the Gates-Glidden group. On the other hand, were observed difference for LA Axxess (p=0.002) and Easy Pro-Design (p=0.005). In the intergroup analysis, were observed difference in all levels, especially for Gates-Glidden in the ascendant order (ANOVA and Tukey). Conclusion: Within the limitations of these study, is possible to conclude that the protocol with greater wear in the cervical risk area was the Gates-Glidden in step-back sequence, as the other groups were equivalent (p>0.05).

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“…The present study found similar rates of dentin removal compared to previous studies 4,[9][10][11][12][13][14][15]24 .…”

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

Pinto

Marceliano-Alves

Lins

et al. 2016

Rev. odontol. UNESP

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“…Root canals obturated only with sealer are apt to leak because of shrinkage, erosion, and dissolution of the material (Wilson & Batchelor 1970, W'iener & Schilder 1971, Orstavik 1983, Peters 1986. Within a short time after placement, most root fillings become permeable to small molecules (Kapsimalis & Evans 1966, Kerekes & Rowe 1982, Johnson & Zakariasen 1983, Osins ct al. 1983, Kennedy et al 1986.…”

Section: Introductionmentioning

confidence: 99%

Particles and molecules in endodontic leakage

1989

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It is assumed that above a critical level, microleakage causes periapical disease and jeopardizes periapical tissue repair. The purpose of this investigation was first to find out to what degree obturation prevents leakage of bacteria-sized particles or large protein molecules, and second if leakage of the commonly used dye methylene blue is comparable with that of a small bacterial metabolic product of similar molecular size. Sections, 9 mm long, obtained from 46 extracted human incisor roots had their root canals prepared in a standardized manner and obturated in four experimental ways using gutta-percha. The root sections were mounted in the middle of tubes that were closed at both ends with rubber membrane stoppers, which permitted sampling from the apical reservoir. The coronal reservoir was filled with a solution of 1 mg/ml latex beads, 4 micrograms/ml endotoxin, 0.5 per cent butyric acid, 0.1 per cent valeric acid and 0.1 per cent methylene blue water. After 1 and 2 weeks, samples were taken from the apical reservoir and tested for the presence of latex beads by phase-contrast microscopy, for endotoxin with a limulus lysate test, for butyric acid with gas-chromatography and for methylene blue with spectrophotometric analysis. Leakage of bacteria-sized particles and large-sized protein molecules could be prevented only when both sealer and pressure were used in obturating root canals with gutta-percha. Leakage of butyric acid proved to be comparable with leakage of methylene blue; microleakage of these small molecules could not be prevented in this study whatever method of filling was used.

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Assessment of different dyes used in leakage studies

et al. 2009

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The goal of this in vitro study was to identify the most suitable dye for endodontic dye leakage studies, which could be a further step towards standardisation. The root canals of 70 extracted, single-rooted human adult teeth were enlarged to apical size 50 using hand instruments. The teeth were divided into seven groups (n = 10 each), and all root canals were completely filled by injection with one of the following dyes: methylene blue 0.5% and 5%, blue ink, black ink, eosin 5%, basic fuchsin 0.5% and drawing ink. Transverse root sections from the coronal, middle and apical part of the roots were examined, and the percentage of the dentine penetrated by dye was evaluated by software-supported light microscopy. In addition, the range of particle size of drawing ink particles was evaluated. There were conspicuous differences in the relative dye penetration into the root dentine and the penetration behaviour in the different root sections (two-way ANOVA, both p < 0.0001). One dye (drawing ink) penetrated less into the root dentine compared with all the others (p <0.0001). The particle size of this agent (0.1-2 microm) corresponds best with the size range of a representative selection of 21 species of pathogenic endodontic bacteria. Compared to the other dyes tested, drawing ink appears to be superior for use in endodontic dye leakage studies. The penetration behaviour into the root dentine of all the other dyes tested might be one factor that limits the applicability of these dyes in dye leakage studies.

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Spectrophotometric analysis of microleakage in the fine curved canals found in the mesial roots of mandibular molars

Cited by 19 publications

References 32 publications

The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

Particles and molecules in endodontic leakage

Assessment of different dyes used in leakage studies

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