A comparison of the apical dye penetration patterns shown by methylene blue and india ink in root-filled teeth

Sealing ability of various endodontic sealers with or without ethylenediaminetetraacetic acid (EDTA) treatment on bovine root canal

This study investigated the wettability and consistency of various endodontic sealers, both inorganic and organic, and evaluated their sealing ability of root canals using the single-cone obturation technique, with and without ethylenediaminetetraacetic acid (EDTA) treatment. Bovine root canals were endodontically prepared and filled in preparation for the dye penetration test with toluidine blue solution. All sealers exhibited contact angles similar to or lower than dentin and displayed superior consistency. Among the sealers, organic sealers used without EDTA treatment showed reduced dye penetration compared to inorganic sealers. However, some inorganic and organic sealers showed dye penetration in the sealer and dentin of root canals subjected to EDTA treatment. In conclusion, the single-cone obturation technique, combined with these endodontic sealers, achieved close contact with root canal dentin due to their wettability and consistency. However, the sealing ability of certain sealers was influenced by EDTA treatment.

Comparative Evaluation of the Sealing Ability of Mineral Trioxide Aggregate (MTA)-Based, Resin-Based, and Zinc Oxide Eugenol Root Canal Sealers: An In Vitro Study

Root canal therapy is a crucial procedure in endodontics that is done to achieve complete obliteration of the root canal space. The success of this therapy depends on achieving a proper seal, which is facilitated using root canal sealers. This study aimed to compare the apical sealing ability of three different root canal sealers: MTA Fillapex, AH Plus, and zinc oxide eugenol (ZOE), using the dye penetration method. Forty freshly extracted single-rooted human maxillary incisors were collected and prepared for the study. The root canals were instrumented using the ProTaper system, and the canals were then obturated using the lateral condensation technique with the respective sealers. After one week of storage, the samples were coated with nail varnish, immersed in a rhodamine B dye solution, and then sectioned longitudinally. The depth of dye penetration was measured, and the results were analyzed statistically. The results revealed significant differences in apical leakage among the three experimental groups. Group 2 (AH Plus) showed the minimum leakage with a mean of 0.13 mm, while Group 4 (no sealer) exhibited the maximum leakage with a mean of 4.49 mm. Group 3 (ZOE) showed an intermediate level of leakage with a mean of 2.37 mm. The statistical analysis confirmed the significant difference in mean leakage among the groups. The findings of this study indicate that AH Plus exhibited superior apical sealing ability compared to MTA Fillapex and ZOE. AH Plus is a resin-based sealer known for its dimensional stability. On the other hand, MTA Fillapex, a newly introduced sealer containing mineral trioxide aggregate, resin, and silica, showed promising sealing properties but had slightly higher leakage compared to AH Plus. ZOE, a traditional sealer, demonstrated relatively higher leakage than the other sealers. In conclusion, choosing a root canal sealer is crucial in achieving a successful endodontic treatment outcome. AH Plus demonstrated superior apical sealing ability among the three sealers tested. Further research and long-term clinical studies are warranted to validate these findings and assess the impact of sealer choice on treatment outcomes and post-endodontic healing.

Methodologies used for testing the sealability of endodontic temporary fillings in vitro: A narrative review

Introduction

The ability of the temporary filling to seal endodontic access cavities may be crucial for the success of endodontic treatment. Numerous in vitro studies have investigated the sealability of the temporary fillings used in endodontic treatments. However, in vitro sealability studies have been criticized for their inconsistent results and questionable clinical relevance. Some journals have imposed moratoriums on publishing such studies to encourage researchers to test their validity and clinical relevance. Since the implementation of this moratorium, little progress has been made in this field. To further encourage researchers to investigate the reliability of these studies, this review presents an overview of the methodologies of studies that examine the ability of temporary filling materials to seal the endodontic access cavity in vitro and discusses the criticisms of these studies in detail.

Materials and Methods

PubMed, Scopus, and Embase electronic databases were searched to identify studies that tested in vitro the ability of temporary filling materials to seal endodontic access cavities. Only original articles published in English between 01/01/1970 and 28/02/2022 were included.

Results

The search yielded 551 results. After removing duplicates and excluding studies that did not meet the inclusion criteria, 94 studies were included in this review.

Conclusion

Although clinical studies may be the best way to test the performance of temporary fillings, the ethical importance of conducting preliminary in vitro studies is undeniable. It seems that questioning the reliability of in vitro sealability studies is not based on sufficient scientific evidence and that the inconsistencies in the results of these studies may be due to differences in the methodological and clinically relevant variables between them, rather than due to their unreliability.

Methylene Blue Penetration of Resin Infiltration and Resin Sealant in Artificial White-Spot Lesions

OBJECTIVE

 This study determined the potency of resin infiltrations and resin sealant in impeding microleakage on artificial white-spot lesions (AWL) by methylene blue penetration.

MATERIALS AND METHODS

 Eighty AWL specimens were randomly separated into two groups for water storage for 24 hours (groups 1-4) and 20,000 cycles of thermocycling (TC) (groups 5-8). Each group was then separated into four subgroups (n = 10) based on the AWL surface treatments: (1) no Tx, (2) treated with resin infiltration (ICON, DMG, Hamburg, Germany), (3) treated with resin infiltration (Surface pre-reacted glass-ionomer (S-PRG) barrier coat, SHOFU, Kyoto, Japan), (4) treated with resin sealant (Clinpro sealant, 3M ESPE, Minnesota, United States). Nail varnish was covered to all samples, with the exception of a 4 × 4 mm2 patch on the buccal measurement region, which was subsequently submerged in a 2% methylene blue solution and cut into buccolingual sections. Stereomicroscope measurements were used to calculate methylene blue penetration scores.

STATISTICAL ANALYSIS

 The Kruskal-Wallis test and the Bonferroni post-hoc correction were performed to evaluate the data.

RESULTS

 Application of resin infiltrants and resin sealant reduced microleakage in AWL by methylene penetration both before and after thermal cycling. In addition, group 6 (ICON + TC) and group 7 (S-PRG + TC) had a significantly different value from group 8 (sealant + TC).

CONCLUSION

 Both the resin infiltration approach and the resin sealant seem to help seal AWL and might perhaps offer long-term defense against microleakage in AWL caused by methylene blue penetration. The greatest sealing and defense for microleakage in AWL were demonstrated by the resin infiltrations.

Evaluation of coronal microleakage of intra-orifice barrier materials in endodontically treated teeth: A systematic review

Background

Endodontic success depends on complete sealing of the root canal orifice to prevent re-infection and re-Contamination of the treated teeth through microleakage. Intra-orifice barrier material provides a seal against micro-organisms, its by-products thus, preventing microleakage and subsequent endodontic failure. Several studies have been done to evaluate microleakage after placing various materials as IOB, but still there is no standardization for the same. Thus, this systematic review was conducted to evaluate the microleakage associated with mineral trioxide aggregate (MTA), composite, and glass ionomer cement (GIC) when used as IOB material.

Materials and Methods

Protocol was formulated in accordance with PRISMA checklist 2020 and registered on PROSPERO (CRD42021226225). Electronic search from databases such as Medline/PubMed, Scopus, EBSCOhost, Embase, Google Scholar, and Cochrane were performed from the year 2000-2020. In vitro and ex vivo studies evaluating coronal microleakage after placing IOB material using methylene blue dye penetration test under a stereomicroscope were included. A total of 5 studies were included in the systematic review. After assessing the risk of bias using customized criteria referred from JBI critical appraisal tool, characteristics of the included studies, reason for exclusion of the studies, and data extraction sheet were prepared.

Results

All studies included in this systematic review reported that placement of an IOB material significantly reduces microleakage as compared to control groups. MTA used as an IOB showed less microleakage than composite and GIC.

Conclusion

MTA as IOB material demonstrated the least microleakage in vitro studies. However, in this systematic review, only in vitro studies were included. Thus, more studies in the form of randomized control trials are required to give a conclusive and definitive result.

Microleakage of resin infiltration in artificial white-spot lesions

This study examined the effectiveness of resin infiltration in inhibiting microleakage from artificial white-spot lesions (AWL) in enamel. Fifty sound extracted premolars were selected and randomly divided into five groups (n = 10 each). Group 1 included sound teeth. In contrast, an AWL was created in all specimens in groups 2 to 5, as follows-Group 2: AWL with no treatment; Group 3: AWL treated with resin infiltration; Group 4: AWL treated with resin infiltration and 5,000 cycles of thermocycling; Group 5: AWL treated with resin infiltration and 10,000 cycles of thermocycling. All specimens were then coated with nail varnish, except for a 4 × 4 mm² area on the buccal surface (the measurement area), immersed in 2% methylene blue solution, and sectioned buccolingually. Microleakage was evaluated with a stereomicroscope. Data were analyzed by using the Kruskal-Wallis test and Bonferroni post-hoc correction. Application of resin infiltrant reduced microleakage in AWL. No microleakage was seen in Group 3, and differences between Groups 3, 4, and 5 were not significant (P > 0.05). The resin infiltration technique appears to aid in sealing enamel AWL and may help provide long-term protection against microleakage in enamel AWL.

August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data

August Krogh twice won the prestigious international Steegen Prize, for nitrogen metabolism (1906) and overturning the concept of active transport of gases across the pulmonary epithelium (1910). Despite this, at the beginning of 1920, the consummate experimentalist was relatively unknown worldwide and even among his own University of Copenhagen faculty. But, in early 1919, he had submitted three papers to Dr Langley, then editor of The Journal of Physiology in England. These papers coalesced anatomical observations of skeletal muscle capillary numbers with O₂ diffusion theory to propose a novel active role for capillaries that explained the prodigious increase in blood-muscle O₂ flux from rest to exercise. Despite his own appraisal of the first two papers as "rather dull" to his friend, the eminent Cambridge respiratory physiologist, Joseph Barcroft, Krogh believed that the third one, dealing with O₂ supply and capillary regulation, was"interesting". These papers, which won Krogh an unopposed Nobel Prize for Physiology or Medicine in 1920, form the foundation for this review. They single-handedly transformed the role of capillaries from passive conduit and exchange vessels, functioning at the mercy of their upstream arterioles, into independent contractile units that were predominantly closed at rest and opened actively during muscle contractions in a process he termed 'capillary recruitment'. Herein we examine Krogh's findings and some of the experimental difficulties he faced. In particular, the boundary conditions selected for his model (e.g. heavily anaesthetized animals, negligible intramyocyte O₂ partial pressure, binary open-closed capillary function) have not withstood the test of time. Subsequently, we update the reader with intervening discoveries that underpin our current understanding of muscle microcirculatory control and place a retrospectroscope on Krogh's discoveries. The perspective is presented that the imprimatur of the Nobel Prize, in this instance, may have led scientists to discount compelling evidence. Much as he and Marie Krogh demonstrated that active transport of gases across the blood-gas barrier was unnecessary in the lung, capillaries in skeletal muscle do not open and close spontaneously or actively, nor is this necessary to account for the increase in blood-muscle O₂ flux during exercise. Thus, a contemporary model of capillary function features most muscle capillaries supporting blood flow at rest, and, rather than capillaries actively vasodilating from rest to exercise, increased blood-myocyte O₂ flux occurs predominantly via elevating red blood cell and plasma flux in already flowing capillaries. Krogh is lauded for his brilliance as an experimentalist and for raising scientific questions that led to fertile avenues of investigation, including the study of microvascular function.

Stereomicroscopic Dye Leakage Measurement of Six Different Root Canal Sealers

INTRODUCTION

Hermetic sealing of the root canal is the most desirable outcome of any root canal treatment, but almost always the filling of the root canal is defective, which is a multifactorial outcome. One such factor majorly influencing the obturation is the root canal sealer used.

AIM

The present study was done for evaluating microleakage in different root canal sealers.

MATERIALS AND METHODS

Sixty extracted human single rooted teeeth were used in this in-vitro study. Sealers tested for microleakage in this study were zinc oxide eugenol based sealer, Sealapex, AH Plus, MTA Plus, EndoRez, Endosequence BC. All the specimens were examined under stereomicroscope for microleakage and the obtained data were statistically analysed using One-way ANOVA test and Tukey's multiple comparision tests using the software GraphPad Prism 7.02.

RESULTS

The Endosequence BC group showed the least dye leakage and the highest leakage was seen in Zinc oxide Eugenol based sealer.

CONCLUSION

Bio ceramic salers being hydrophilic show better sealing ability compared to resin based and eugenol based sealers.

Importance and methodologies of endodontic microleakage studies: A systematic review

INTRODUCTION

It is very important to obtain a tight seal in obturated root canal, making it necessary to conduct clinical or laboratory studies on the sealability of endodontic materials. Different methodologies have been historically used to assess microleakage of different endodontic materials. The aim of the present study was to comprehensively review different material testing methods used in microleakage studies, their interpretation and importance in endodontic literature.

MATERIAL AND METHODS

A systematic search was conducted in Medline, Cochrane, and Web of Science databases. In addition, the reference lists of review articles on the topic were searched. No language restriction was applied. Two independent reviewers screened the article.

RESULTS

Microleakage is considered the single most important risk factor responsible for apical periodontitis. Dye penetration, dye diffusion, bacterial and endototoxin infiltration, fluid filtration, glucose, caffeine and protein infiltration, radioisotope penetration, animal studies, and electrochemical or 3D evaluation are different methodologies used to assess dental leakage. 91 out of 177 articles in the primary search were included in the study. These methods are very divergent in their viewpoints; that is why their results cannot be easily compared. It is necessary to standardize microleakage detection methods in order to more correctly evaluate the phenomena that are found between the root canal wall and the root canal filling materials.

CONCLUSIONS

All the methods are useful if studies are performed strictly with large sample sizes and proper control groups and if the technique can be standardized. Furthermore, more evaluations of the reliability of the methods are strongly recommended. Key words:Dental leakage, review, root canal, material testing methods, data interpretation.

Accuracy of Different Methods for Assessing Erosive Tooth Wear

The detection of exposed dentine caused by erosive tooth wear is difficult. To the authors’ knowledge, there are no studies available on the impact of magnification and/or dye on the detection of erosive lesions. Therefore, the aim of this study was to investigate if the accuracy of assessing exposed dentine by the naked eye could be improved by using a microscope, dyeing, or a combination of both. The collected data were compared with the assessment of histological sections, which was considered the gold standard. A total of 70 teeth (24 teeth with slight erosion and 46 teeth with dentine involvement) showing different grades of erosive tooth wear were assessed 4 times by 17 examiners (9 aged <40 y, 8 aged ≥40 y). The first assessment was performed without magnification and without dye, the second assessment with magnification and without dye, the third assessment without magnification and with dye, and the fourth assessment with magnification and with dye. The examiners decided if dentine was exposed in the area of interest (positive test result) or not (negative test result). Subsequently, the teeth were histologically evaluated. Enamel was still present in 6 teeth and dentine was exposed in 64 teeth. Microscope magnification without dye performed the best, with 86% of all assessments being correct. The use of microscope magnification had a significant impact for dentists older than 40 y ( P = 0.02). The authors conclude that the assessment of exposed dentine was best when a microscope was used alone and that an additional dyeing of the samples did not improve performance.

Knowledge Transfer Statement: Clinicians can use the results of this study when they assess erosive tooth wear. It will help clinicians to detect erosive tooth wear correctly, particularly the involvement of dentine. Using a microscope in the diagnostic process has a direct impact on the right assessment and consequently on prevention and/or minimally invasive treatment.

Comparison of Microleakage of MTA and CEM Cement Apical Plugs in Three Different Media

Introduction:

Microleakage is of the causes of endodontic treatment failure. The aim of this in vitro study, was to compare the microleakage of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement apical plugs in three environments.

Methods and Materials:

A total of 130 human extracted single rooted teeth were collected. After decoronation, preparation of the root canal space and simulation of open apices, 5 teeth were selected as positive and negative control groups and the rest of the samples were randomly divided into two groups (MTA plug and CEM cement plug) and each group was divided into 3 subgroups (dry, contaminated with saliva and contaminated with blood). In each group apical plug was placed into the canal. After full setting of the apical plug, microleakage of the samples were evaluated using fluid filtration method and the data were analyzed using two-way analysis of variance.

Results:

In dry and saliva contaminated environments, the leakage of MTA samples were 40.906±2.081 and 39.608±2.081, respectively which was significantly more than that of CEM cement samples (26.977±2.081 and 27.000±2.081, respectively). However, in blood-contaminated environments, the amount of leakage in MTA group (21.640±2.081) was significantly lower than CEM cement group (44.358±2.081).

Conclusion:

According to the results of this study, in dry and saliva-contaminated conditions CEM cement provides significantly better seal in comparison to MTA

Comparative evaluation of intracanal sealing ability of mineral trioxide aggregate and glass ionomer cement: An in vitro study

Aims:

The purpose of this study was to compare the sealing ability of Mineral Trioxide Aggregate (MTA) and Glass Ionomer Cement (GIC) when used over gutta-percha as intracanal sealing materials. The study also evaluated the sealing ability of Zinc oxide eugenol (ZOE) cement and Acroseal sealer.

Materials and Methods:

Teeth were obturated with gutta-percha using sealer ZOE (group A, C, D) and Acroseal (group B). The groups were further divided into 2 subgroups (15 premolars each) on the basis of intracanal sealing material used: GIC subgroups (A1, B1) and MTA in subgroups (A2, B2). The clearing technique was used in this study for leakage evaluation. Seventy mandibular premolars were prepared using step-back technique and divided into experimental groups A and B (30 premolars each) and the positive and negative control groups C and D (5 premolars each).

Statistical analysis used:

Coronal microleakage was determined under stereomicroscope using 15X magnification. Data was statistically analyzed using one-way ANOVA followed by Post-Hoc Multiple comparison (Bonferroni).

Results:

MTA group leaked significantly less than GIC group (P < 0.05). Acroseal exhibited better sealing ability than ZOE sealer. Teeth with no intracanal barrier showed almost complete leakage.

Conclusions:

MTA may be preferred over GIC as an intracanal barrier.

Influence of fiber inserts, type of composite, and gingival margin location on the microleakage in Class II resin composite restorations

This study evaluated the influence of fiber inserts, type of composites, and location of the gingival seat on microleakage in Class II resin composite restorations. Fifty noncarious human third molars were selected for the study. Standardized Class II box type cavities were prepared on the mesial and distal side of 45 teeth. The gingival margin was placed above the cementoenamel junction (CEJ) on the mesial side and below the CEJ on the distal side. The remaining five teeth received no cavity preparations. The prepared samples were divided randomly on the basis of type of composite and presence or absence of fiber inserts, into four experimental groups of 10 teeth each and two control groups of five teeth each. The groups were defined as follows: group I (n=10) - Z350 XT; group II (n=10) - Z350 XT with fibers; group III (n=10) - P90; group IV (n=10) - P90 with fibers; and group V (n=5) - positive controls, cavities were not restored; group VI (n=5) - negative controls, no cavities were prepared. The samples were stored in distilled water in incubator at 37°C for 24 hours and then subjected to 500 cycles of thermocycling (5°C and 55°C) with a dwell time of 15 seconds. They were then placed in a 2% methylene blue dye solution for 24 hours at 37°C. Samples were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margin under a stereomicroscope at 20× magnification. Kruskal-Wallis and Mann-Whitney U-tests were used to compare the mean leakage scores. Restorations with gingival margins in enamel showed significantly less microleakage. Significant reduction in microleakage was observed in groups restored with P90 composite than those restored with Z350 XT. No improvement in microleakage was observed with the use of fiber inserts (p>0.05).

Evaluation of apical sealing ability of four different sealers using centrifuging dye penetration method: an in vitro study

AIM

The aim of this in vitro study was to evaluate the apical seal obtained with four root canal sealers AH 26, Sealapex, Endoflas FS and AH Plus, with lateral condensation.

MATERIALS AND METHODS

Sixty root canals were prepared using the step-back technique. The specimens were divided into four experimental groups of 12 teeth and two control groups of 12 teeth. The experimental groups were obturated by laterally condensed gutta-percha with one of the tested sealers and control groups were obturated without any sealer. Methylene blue dye penetration with centrifuging method was used to evaluate the apical sealing ability. The quantitative apical leakage of each specimen was measured after 2 weeks.

RESULTS

The results showed no significant differences between all groups except between AH Plus and Endoflas FS (<0.05). AH Plus showed significantly less leakage than Endoflas FS.

CONCLUSION

AH Plus showed the least leakage compared to AH 26, Sealapex and Endoflas FS.

Influence of calcium hydroxide on dyes for dentin labeling, anlyzed by means of a new methodology

The objective of this study was to evaluate the influence of calcium hydroxide in intracanal dressing on the ability of the dyes rhodamine B and methylene blue to label the dentine. Forty extracted human mandibular premolars had their canals instrumented and were divided into four groups: in two groups, the canals were filled with a calcium hydroxide paste and the others remained in distilled water. After 15 days, in two groups (with and without dressing), the canals were obturated with sealer containing methylene blue, whereas the others contained rhodamine B. For analysis, the roots were transversally sectioned in their cervical, medium and apical thirds, and the labeling was analyzed. The Mann-Whitney test showed statistically significant difference between the dressing/methylene blue group and the others. Based on these results, it was concluded that calcium hydroxide in intracanal dressing negatively interferes with the labeling ability of methylene blue.

Effect of Synthetic Tissue Fluid on Microleakage of Grey and White Mineral Trioxide Aggregate as Root-End Filling Materials: An in vitro study

OBJECTIVES

The success of endodontic surgery has been shown to depend partly on the apical seal. Grey mineral trioxide aggregate (GMTA) produces hydroxyapatite twice as often as white mineral trioxide aggregate (WMTA) when suspended in a phosphate buffered saline (PBS) solution. The aim of this in vitro study was to compare the microleakage phenomenon of gray and white mineral trioxide aggregates as root-end filling materials after immersion in synthetic tissue fluid (STF).

METHODS

55 single-rooted extracted maxillary anterior human teeth were divided into two experimental groups of 20 teeth each, plus 3 groups of 5 teeth each as two negative and one positive control groups. The root canals were cleaned, shaped, and laterally compacted with gutta-percha. The root ends were resected and 3 mm deep cavities were prepared. The root-end preparations were filled with GMTA or WMTA in the experimental groups. Leakage was determined using a dye penetration method. Data were analysed using analysis of variance (ANOVA) at the 0.05 level of significance.

RESULTS

The mean dye leakage was 0.40 ± 0.1 mm for GMTA and 0.50±0.1 mm for WMTA groups, respectively. There was no significant difference between the two experimental groups (P = 0.14).

CONCLUSION

Despite the different properties and behaviours of GMTA and WMTA in STF, there were no significant differences in microleakage when using GMTA or WMTA.

Dynamic sealing ability of MTA root canal sealer

AIMS

To evaluate (i) the sealing ability of two sealers, mineral trioxide aggregate sealer (MTAS) and Pulp Canal Sealer (PCS), used with gutta-percha utilizing the fluid filtration method, (ii) leaching and surface characteristics in Hank's balanced salt solution (HBSS) over a period of time.

METHODOLOGY

Surface characteristics in HBSS were evaluated under the scanning electron microscope after 1 and 28 days, and the leaching of both sealers were assessed by inductively coupled plasma atomic absorption spectrometry (ICP-AAS). In addition, 24 single rooted extracted teeth were root filled using warm vertical compaction with either MTAS or PCS used as sealers with gutta-percha. Four teeth were used as positive and negative controls. Sealing ability was evaluated after 1 or 28 days using the fluid filtration method.

RESULTS

Mineral trioxide aggregate sealer exhibited crystalline deposits rich in calcium and phosphorus on its surface when in contact with a physiological solution. These crystalline deposits were absent in PCS and on MTAS stored at 100% humidity. The sealing ability of MTAS was similar to that of PCS.

CONCLUSIONS

The novel sealer based on mineral trioxide aggregate had comparable sealing ability to a proprietary brand sealer cement. In contact with a simulated body fluid, the MTA sealer released calcium ions in solution that encouraged the deposition of calcium phosphate crystals.

Assessment of different dyes used in leakage studies

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.

Evaluation of the effect of tracer pH on the sealing ability of glass ionomer cement and mineral trioxide aggregate

OBJECTIVES

The aim of this study was to evaluate the sealing ability and physical and chemical properties of glass ionomer cement (GIC) and mineral trioxide aggregate (MTA) using Rhodamine B at different pHs as tracer.

METHODS

Chemical analysis, pH and micro-hardness of GIC and MTA were performed. In addition dye leakage was assessed by tracer leakage using Tandem Scanning Confocal Microscope (TSM) after immersion of premolar teeth in a stock and a buffered fluorescent Rhodamine B for 24 h. Ultra-structural changes within the materials were evaluated by viewing under the field emission scanning electron microscope (FESEM).

RESULTS

GIC and MTA showed elemental peaks for silicon, aluminium and calcium while MTA also had bismuth. GIC was acidic (P = 0.001) and caused an increase in dye pH (P = 0). Immersion of MTA in any of the test solutions resulted in an increase in the pH of the solution (P < 0.05). Use of a dye solution of lower pH than the material under test increased the cement micro-hardness. GIC demonstrated marginal leakage on TSM and both increase in marginal leakage and material porosity on FESEM. MTA was not affected by the use of acidic dye but showed a tendency to take up dye within the material shown on TSM.

CONCLUSIONS

Evaluation of marginal adaptation of dental materials was shown to be dependent on the technique used for viewing the material to tooth interface, the properties of the material under study and the pH of the dye used.

Ex vivo microscopic assessment of factors affecting the quality of apical seal created by root-end fillings

AIM

(i) To evaluate the incidence of microcracks around root-end preparations completed with ultrasonic tips and their relationship with the root filling technique and thickness of surrounding dentine. (ii) To investigate the effect of rapid exposure to a water-soluble dye of Intermediate Restorative Material (IRM), Super Ethoxybenzoic Acid (sEBA) and Mineral Trioxide Aggregate (MTA), on the marginal adaptation and microleakage of root-end fillings. (iii) To describe the microstructure of the surface of root-end filling materials.

METHODOLOGY

Ninety-two single-rooted teeth were divided into two groups (n = 46) according to the root canal instrumentation/filling techniques. Group 1 consisted of specimens in which canal preparation was completed using a crown-down technique and then filled with the Thermafil system (TF group); Group 2 consisted of specimens in which canal preparation was completed using a step-back technique and lateral condensation (LC group). Following root-end resection and ultrasonic cavity preparation, the samples were further divided into three subgroups (n = 24) for root-end filling with IRM, sEBA or MTA. The ultrasonic preparation time was recorded. Eight teeth were kept as positive and 12 as negative controls. Following immersion in Indian ink for 7 days, all resected root surfaces were evaluated for the presence of microcracks and the cross-sectional area of root-end surface and root-end filling were measured to evaluate the thickness of the dentinal walls. Thereafter, the samples were sectioned longitudinally so as to assess the depth of dye penetration and marginal adaptation of root-end fillings. Negative controls longitudinally sectioned were used to describe microstructural characteristics of the root-end filling materials using scanning electron microscopic (SEM) techniques.

RESULTS

Although the thickness of dentinal walls between groups 1 and 2 was similar, the ultrasonic preparation time and number of microcracks were significantly higher (P < 0.001) in the TF group. Both groups had a significant correlation between microcracks and ultrasonic preparation time (P < 0.001). sEBA and IRM had better adaptation and less leakage compared with MTA. A SEM analysis displayed microstructural differences between the root-end filling materials.

CONCLUSION

Microcracks can occur independently of the thickness of dentinal walls and may be associated with the prolonged ultrasonic preparation time required for the removal of the root filling during root-end cavity preparation. Although sEBA and IRM had better behaviour than MTA regarding microleakage and marginal adaptation, it is possible that exposure of MTA to a water-soluble dye before achieving full set and its porous microstructure contributed to the results.

The Fat Compartments of the Face: Anatomy and Clinical Implications for Cosmetic Surgery

BACKGROUND

Observation suggests that the subcutaneous fat of the face is partitioned as distinct anatomical compartments.

METHODS

Thirty hemifacial cadaver dissections were performed after methylene blue had been injected into specified regions. Initial work focused on the nasolabial fat. Dye was allowed to set for a minimum of 24 hours to achieve consistent diffusion. Dissection was performed in the cadaver laboratory using microscopic and loupe magnification.

RESULTS

The subcutaneous fat of the face is partitioned into multiple, independent anatomical compartments. The nasolabial fold is a discrete unit with distinct anatomical boundaries. What has been referred to as malar fat is composed of three separate compartments: medial, middle, and lateral temporal-cheek fat. The forehead is similarly composed of three anatomical units including central, middle, and lateral temporal-cheek fat. Orbital fat is noted in three compartments determined by septal borders. Jowl fat is the most inferior of the subcutaneous fat compartments. Some of the structures referred to as "retaining ligaments" are formed simply by fusion points of abutting septal barriers of these compartments.

CONCLUSIONS

The subcutaneous fat of the face is partitioned into discrete anatomic compartments. Facial aging is, in part, characterized by how these compartments change with age. The concept of separate compartments of fat suggests that the face does not age as a confluent or composite mass. Shearing between adjacent compartments may be an additional factor in the etiology of soft-tissue malposition. Knowledge of this anatomy will lead to better understanding and greater precision in the preoperative analysis and surgical treatment of the aging face.

Sealing Ability of New Adhesive Root Canal Filling Materials Measured by New Dye Penetration Method

The sealing ability of new adhesive root canal filling materials was evaluated using a new dye penetration method. Twenty-eight single-rooted mandibular premolars were randomly divided into four groups of seven teeth each and filled by lateral condensation using one of these combinations: Resilon point with Epiphany sealer (RE); gutta-percha point with Sealapex sealer (GS); gutta-percha point with dentin activator and Superbond sealer (GDS); or gutta-percha point with Accel primer, dentin activator, and Superbond sealer (GADS). Amount of 0.06% methylene blue dye solution (MB) that leaked from the coronal portion to the apical area was measured with a spectrophotometer at one, four, eight, 15, and 30 days in an accumulative manner. The total amount of leaked MB on day 30 was significantly higher for GDS than the other combinations (p < 0.05).

Influence of moisture on the apical seal of root canal fillings with five different types of sealer

The aim of this study was to evaluate the influence of moisture on apical leakage using five different types of sealer. There were 120 single-rooted teeth instrumented to .02/#60 and randomly assigned to 10 experimental groups, one control group (AH Plus, lateral condensation) (n = 10) or positive/negative controls (n = 5). Before obturation teeth were dried thoroughly, followed by recontamination with moisture in a wet chamber (moist groups; 37 degrees C for 7 days). The teeth of the experimental groups (a, dry; b, moist) were obturated with sealer (groups 1, AH Plus; 2, Apexit; 3, Ketac-Endo; 4, RoekoSeal; 5, Tubli-Seal) and a single gutta-percha cone .02/#55. Teeth were centrifuged (30 x g for 3 minutes) in 5% methylene blue. Linear dye penetration was measured under a stereomicroscope. Moisture led to less microleakage for Apexit, RoekoSeal, and Tubli-Seal and higher values for AH Plus and Ketac-Endo. Multifactorial ANOVA displayed a significant dependence of leakage on sealer (p < 0.001) and the combination sealer or moisture (p < 0.01). It depends on the sealer type in which way moisture affects the apical seal.

Methodologies for assessment of apical and coronal leakage of endodontic filling materials: a critical review

Apical leakage continues to be a topic of great interest, because in spite of the advances in Endodontics, clinical failures still occur. Most failures are probably attributed to the proliferation of bacteria that remain viable after chemical-mechanical preparation and cause periapical tissue irritation. Coronal leakage has aroused researchers' interest over the last few years, since canals may be re-contaminated after loss of coronal sealing or fracture of the remaining tooth. In this review, the various methodologies used for assessing root canal sealing capacity are critically analyzed, as they are not standardized, which makes it difficult to compare the results obtained when different methodologies are used, even though the same substrate is being assessed.

Microleakage evaluation of intraorifice sealing materials in endodontically treated teeth

OBJECTIVE

Evaluate intraorifice sealing materials Cavit, Vitremer, and Flow-It for the prevention of coronal microleakage in root-canal treatment.

STUDY DESIGN

Root-canal treatment was performed on 80 extracted human molars. Three millimeters of coronal gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the 3 filling materials. After thermocycling (5 degrees C to 55 degrees C) and 5 days of immersion in dye, the teeth were cleared for stereomicroscope evaluation for evidence of dye penetration into the sealing material and along canal walls.

RESULTS

All groups showed dye penetration into the root canal. Cavit sealed significantly better than the other groups (P < .01), preventing the coronal leakage in 90% of the specimens. Flow-It exhibited the highest leakage (65% of specimens) and did not differ significantly from the Vitremer group, which showed dye penetration in 55% of specimens.

CONCLUSION

Cavit sealed significantly better than Vitremer and Flow-It when used as intraorifice filling materials.

Fixation of periprosthetic femoral shaft fractures associated with cemented femoral stems: a biomechanical comparison of locked plating and conventional cable plates

To determine which of 2 techniques for the treatment of periprosthetic femoral shaft fractures is of greater stiffness.

DESIGN

A laboratory study using 8 pairs of matched, embalmed femurs.

METHODS

Femurs implanted with a cemented total hip prosthesis had a simulated periprosthetic femur fracture created distal to the implant. Fractures were fixed with a plate with locked screws or a plate with cables (Ogden construct). Fixation stability was compared in various loading modalities before and after cycling. Failure in torsional loading was then determined. The cement mantle was tested for crack propagation that may have occurred secondary to locked screw insertion and loading.

OUTCOME MEASUREMENTS

Fixation stiffness (the ratio of applied load to displacement at the fracture site), torsional strength, mode of failure for each system, and cement mantle evaluation for cracks after screw insertion.

RESULTS

Locked plating was stiffer than the Ogden construct in pre- and post-cyclic axial loading and torsion. There was no difference in lateral bending stability or torsional failure loads.

CONCLUSIONS

Locked plating constructs were stiffer than the Ogden construct in axial loading and torsion. Although no differences in loads to failure during torsion were noted, locked plating constructs exhibited catastrophic failure not observed with the Ogden construct.

Evaluation of apical sealing ability and adaptation to dentine of two resin-based sealers

The purpose of this study was to evaluate the apical sealing ability and adaptation to dentine of two resin-based root canal sealers. The root canals of 55 human maxillary anterior teeth were prepared using a step-back technique and the smear layer removed with 17% ethylenediaminetetraacetic acid. The teeth were divided into two groups of 25 teeth and the remaining five teeth served as control. Then the teeth were prepared and obturated with gutta-percha by a lateral condensation and either AH plus and EndoRez used as a sealer. Twenty teeth from each group were used for the apical leakage test and the remaining five teeth from each group were used for examination under the scanning electron microscope (SEM). For apical leakage test, teeth were covered with nail varnish and sticky wax to within 1 mm of the apical foramen and placed in 2% methylene blue for 7 days. After this period, the teeth were sectioned longitudinally and apical leakage measurements made. The mean value of dye penetration for AH plus was 2.87 +/- 0.43 mm, while that of EndoRez was 4.54 +/- 0.36 mm. The difference between mean of dye penetration was statistically significant (P < 0.01). The SEM examination showed both sealers had better adaptation and penetration in coronal and middle thirds than apical third of root canal. In apical third, AH plus was adapted better adpated to dentine than EndoRez. In conclusion, AH plus sealer has better apical sealing ability and adaptation to dentine than EndoRez sealer.

Inflow of ocular surface fluid through clear corneal cataract incisions: a laboratory model

PURPOSE

To evaluate the self-sealing properties of standard clear corneal cataract incisions during two events: (1) application of mechanical external pressure, or (2) controlled fluctuation of intraocular pressure (IOP).

DESIGN

Laboratory investigation.

METHODS

Eight fresh human donor globes were prepared for Miyake video microscopy. A standard two-plane 3-mm clear corneal incision was created and a 3 x 3-mm sponge soaked with India ink was placed on the wound surface. One globe with a sutured corneal wound served as the control. A transcleral cannula was inserted and connected to a bottle of saline. Intraocular pressure was modified varying the bottle height. External pressure was applied through manual contact on different regions of cornea.

RESULTS

Four of seven eyes demonstrated intraocular presence of ink, three of them after external manipulation and another after varying the IOP.

CONCLUSION

Self-sealing properties of unsutured clear corneal wounds were compromised in our model. These data may give insight into the possible mechanisms involved in the inflow of extraocular fluid into the eye through clear corneal cataract incisions.

Effects of calcium hydroxide paste medication on coronal leakage

The purpose of this in vitro study was to examine the coronal leakage of canals medicated with Ca(OH)(2) compared with the canals which did not receive Ca(OH)(2) medication before obturation with laterally condensed gutta-percha points and sealer. Sixty-one single rooted permanent canines and premolars were used. The crowns were removed from the cemento-enamel junction. After the canals were chemomechanically prepared, the roots were divided into three experimental groups as group 1, 2 and 3. The canals in group 1 and 2 were treated with ethylenediaminetetraacetic acid (EDTA) and NaOCl in order to remove the smear layer and then the canals were filled with Ca(OH)(2) paste. The coronal 3 mm of the cavities were sealed with Cavit and the samples were kept in an incubator at 37 degrees C for 7 days. No intra-canal medication was applied in group 3. The root canals were irrigated with NaOCl in group 1 and with EDTA and NaOCl in group 2, in order to remove Ca(OH)(2) before obturation. Two samples from group 1 and two from group 2 were examined under SEM in order to reveal the removal of Ca(OH)(2) paste. Following this, the canals in the experimental groups were obturated with gutta-percha and sealer. The roots were placed in India ink for 7 days and the linear dye penetration was evaluated. No significant statistical difference was found in the amount of coronal dye leakage between experimental groups (P > 0.05). The results of the present study indicated that the application of Ca(OH)(2) as a temporary dressing material had no effect on coronal leakage.

The use of glass ionomer cements in both conventional and surgical endodontics

The capacity to bond to dental tissues, especially to dentine, their long-term fluoride release and their biocompatibility make glass ionomer cements (GICs) advantageous for use in endodontics, as well as in restorative dentistry. This review provides information on the basic properties of GICs, such as adhesion, antimicrobial effects and biocompatibility, particularly as they relate to use in endodontics. Indications for the use of GICs in endodontics are orthograde root canal sealing, root-end filling, repair of perforations and root resorption defects, treatment of vertical fractures and maintenance of the coronal seal. The paper includes a review on each of these indications. It is concluded that in spite of the critical handling characteristics and the inconclusive findings regarding sealing ability and antimicrobial activity, there is substantial evidence to confirm their satisfactory clinical performance. Both soft tissue and bone compatibility make them suitable for use during endodontic surgery.

Effect of three different sealers on the sealing ability of both thermafil obturators and cold laterally compacted Gutta-Percha

The purpose of this study was to assess the seal obtained in straight and curved root canals filled with either laterally compacted gutta-percha or Thermafil obturators. Each technique was used in combination with three different sealers (RSA RoekoSeal, AH Plus, AH 26). Thermafil obturators were also used without sealer, resulting in a total of 14 test groups of 16 teeth each. Sixty teeth served as positive or negative controls. Included in the study were 142 extracted teeth with straight and 142 with curved root canals. All canals were enlarged up to size 40. After obturation, all roots were placed in India ink for 48 h and rendered transparent to measure the maximum linear dye penetration. Canals filled with Thermafil obturators had significantly more extrusion of filling material than canals filled by lateral compaction (p < 0.01). Thermafil without sealer showed significantly greater dye penetration compared with all other groups both in straight and in curved canals (p < 0.05). As long as a sealer was used, the seal obturated with Thermafil was equivalent in terms of dye penetration to lateral compaction. There were no statistical differences in the mean apical dye penetration among the three sealers. The differences between the dye penetration in straight and in curved canals were insignificant for all groups (p > 0.05). Under the conditions of this study, Thermafil obturators achieved seals comparable to lateral compaction, as long as a sealer was used.

Influence of calcium hydroxide intracanal medication on apical seal

AIM

The aim of this study was to determine the influence of calcium hydroxide intracanal medication and various techniques for its removal on the sealing ability of gutta-percha root fillings with a zinc oxide-eugenol sealer.

METHODOLOGY

Eighty extracted mature human mandibular molar roots were divided into three groups of similar root-canal configuration. Calcium hydroxide paste was made by mixing calcium hydroxide powder with distilled water at a powder to liquid ratio of 1:1.25. After root canals were prepared and enlarged to a minimum of size 30 with the Profile 0.06 system, calcium hydroxide paste was placed in the canals of two groups, but no medication was placed in the control group. The intracanal calcium hydroxide was removed with two different techniques, 1 week after medication: K-files one size larger than the master apical file (MAF) were used with 2.5% NaOCl and 15% EDTA solutions in one group, whilst K-files the same size as the MAF were used with 2.5% NaOCl solution in another group. Canals were obturated with gutta-percha and Tubli-Seal cement using the lateral condensation technique. The apical sealing-ability was assessed by dye leakage and cross-sections of the specimens were examined under a stereomicroscope. The dye-penetration level was measured and analyzed using Fisher's exact test and Duncan's multiple range test.

RESULTS

The calcium hydroxide-medicated groups showed significantly more dye leakage than the non-medicated control group (P < 0.05). However, there was no significant difference between the two calcium hydroxide-medicated groups (P > 0.05). The stereomicroscopic views showed a relatively uneven and thicker layer of sealer in the calcium hydroxide-medicated groups.

CONCLUSION

Calcium hydroxide intracanal medication may increase apical leakage of gutta-percha root fillings when a zinc oxide-eugenol sealer is used.

Leakage of interim post and cores used during laboratory fabrication of custom posts

The aim of this study was to compare coronal microleakage in two conditions. Twenty-eight extracted upper molars were endodontically treated and divided into two groups and controls: group A: prefabricated post and core permanently cemented; and group B: prepared for a post and restored with a temporary post crown cemented with a temporary cement. The teeth were thermocycled, immersed in black India ink for 1 week, and made transparent. Results indicated that the permanently cemented, prefabricated post and core produced the best seal (p < 0.01); leakage was significantly greater with the temporary post crown and was similar to that of a positive control group.

In vitro evaluation of a calcium phosphate cement root canal filler/sealer

An in vitro dye leakage study was performed to compare the apical leakage of a fill with injectable calcium phosphate cement (CPC) filler/sealer and a master silver cone with leakage from a fill of Sealapex sealer and laterally condensed gutta-percha. Ten instrumented, extracted, single-rooted human teeth were obturated with either laterally condensed gutta-percha and Sealapex as the sealer or with a single master cone and the CPC paste sealer. Additional teeth were included in the study to serve as controls. The teeth were placed in 1% poly-R dye solution (pH 7.0) for 5 days. After the teeth were longitudinally sectioned apical leakage of dye was measured. There were no significant differences between the CPC and Sealapex groups. The single cone CPC procedure provided an adequate apical seal against dye penetration. Should retreatment become necessary the single cone may be removed to provide access for instrumentation.

Three-dimensional reconstruction: a new method for the evaluation of apical microleakage

The purpose of this study was the evaluation of a new method for studying apical microleakage by using a three-dimensional (3-D) reconstruction method. Fourteen human single-rooted mandibular teeth were used for this work. The canals were prepared with hand instruments by using the step-back technique. To supply a focus to the study of the method, the teeth were divided into two groups that were obturated using two different sealers. India ink was used for passive stain. Serial cross-sections 0.75 mm thick were taken from each specimen by using a special microtome. Each section was photographed under a stereoscopic microscope. Each photograph was digitized and processed to obtain a 3-D reconstruction of the external surface of the teeth, their corresponding prepared root canals, and their apical microleakage. Sample size and experimental methods were not designed to make valid groups; however, apical microleakage was observed in both groups ranging between 2.25 to 8.25 mm height. The 3-D reconstruction method has proved to be a useful tool in the study of apical microleakage.

A comparison of MTA, Super-EBA, composite and amalgam as root-end filling materials using a bacterial microleakage model

AIM

The aim of this study was to compare traditional and newly developed root-end filling materials for resistance to bacterial microleakage.

METHODOLOGY

Sixty extracted single-rooted teeth were randomly divided into five groups for root-end filling with mineral trioxide aggregate, Super-EBA, TPH composite resin with ProBond dentine bonding agent, Dispersalloy amalgam with and without ProBond, and positive and negative control groups. Root canals were instrumented using the step-back technique and simulated root-end resections performed. Root-end filling materials were placed in 3 mm ultrasonic retropreparations. Nail varnish was applied to all external root surfaces to the level of the resected root ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 h. Using a newly designed model system, the apical 3-4 mm of the roots were immersed in BHI culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 h with a suspension of Streptococcus salivarius. Culture media were observed every 24 h for colour change indicating bacterial contamination. Media demonstrating colour change were plated for S. salivarius. Samples were observed for 12 weeks.

RESULTS

At 4 weeks 10% of specimens from each experimental group had evidence of leakage. At 8 weeks 20% of specimens filled with amalgam without dentine bonding agent, Super-EBA and MTA had evidence of leakage. At 12 weeks minor differences between materials were noted.

CONCLUSIONS

Under the conditions of the study, despite some variations, there were no statistically significant differences in rate of microleakage among the five groups tested at either 4, 8 or 12 weeks.