Intraorifice sealing of gutta-percha obturated root canals to prevent coronal microleakage

Survivability of endodontically treated cracked tooth: A systematic review

BACKGROUND

Literature evidence describes various treatment protocols that have been employed for the effectiveness in improving survival and addressing associated symptoms of cracked teeth.

OBJECTIVE

This systematic review investigates the survivability of endodontically treated cracked teeth and associated assessments, focusing on various treatment protocols.

METHODS

The PRISMA guidelines were utilised for guiding the article selection framework of this review. A comprehensive search of relevant literature was conducted in May 2023 across various databases, and studies meeting the inclusion criteria were selected. Data extraction, guided by a standardized form, captured crucial details, including study characteristics, treatment protocols, and treatment outcomes, enhancing the consistency and accuracy of information collection. Data extraction and synthesis was done by two reviewers independently. The Newcastle Ottawa tool was used to measure the methodological quality of the study. Six observational studies were eventually included.

RESULTS

Mandibular molars are particularly prone to developing cracks, with research indicating a heightened susceptibility to this dental issue. Studies reveal that endodontically treated cracked teeth boast robust overall survival rates ranging from 75.8% to 100%. The risk of bias assessment, utilizing the Newcastle Ottawa scale, indicated a moderate risk across studies, highlighting the necessity for careful interpretation of findings.

CONCLUSION

Endodontically treated cracked teeth show marked success in survival, with the incorporation of crowns post-endodontic treatment significantly enhancing longevity and resilience.

An in vitro comparative evaluation of intraorifice barriers and bleaching agents on the fracture resistance of the endodontically treated anterior teeth

Aim

This study aimed to evaluate and compare the impact of different bleaching agents on the fracture resistance of endodontically treated teeth when using either GC Fuji type 2 glass ionomer cement (GIC) or Shofu Glass Ionomer RX EASE as intraorifice barriers (IOB).

Materials and Methods

A total of 80 single-rooted human maxillary central incisors were prepared and obturated. Three millimeters of gutta-percha was then removed from the orifice. The specimens were divided into two primary groups based on the type of IOB material used: GC Fuji type 2 GIC and Shofu Glass Ionomer RX EASE (n = 40). Each group was further divided into four subgroups based on the bleaching agent used: Carbamide peroxide (CP) 37%, sodium perborate (SP), hydrogen peroxide (HP) 35%, and distilled water used as the control (n = 10). The teeth were subjected to fracture resistance testing.

Results

The study found that the order of root fracture resistance was control > CP > SP > HP. There was no statistically significant difference in fracture resistance between GC Fuji type 2 GIC and Shofu Glass Ionomer RX EASE when used as IOB materials.

Conclusion

The study concluded that the choice of bleaching agent significantly affects the fracture resistance of endodontically treated teeth. It was observed that fracture resistance is lowest with HP, followed by SP and CP. Both GC Fuji type 2 Glass Ionomer and Shofu Glass Ionomer RX EASE are effective as IOB.

Biological considerations of dental materials as orifice barriers for restoring root-filled teeth

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.

Orifice barriers to prevent coronal microleakage after root canal treatment: systematic review and meta-analysis

AIMS

This systematic review aimed to compare the efficiency of orifice barriers in preventing coronal microleakage in vitro.

METHODS

Articles published in English, German and Chinese were searched for studies describing microleakage assays for the bacterial penetration of root canal-treated teeth in vitro. The final sample included 18 articles for review and meta-analysis. Risk ratios and confidence intervals were determined for dichotomous variables. Ten publications using bacterial leakage models contributed to the meta-analysis.

RESULTS

The addition of orifice barriers to a root canal filling was overall effective, shown by risk ratios (RR) and 95% confidence intervals (CI) demonstrating reduced microleakage with glass ionomer cement (GIC) (RR 0.37, 95% CI 0.26-0.53, P < 0.001), resin-modified GIC (RR 0.32, 95% CI 0.15-0.67, P = 0.01), composite resin (RR 0.54, 95% CI 0.38-0.75, P < 0.001), mineral trioxide aggregate (MTA) (RR 0.25, 95% CI 0.12-0.52, P < 0.001) and Cavit (RR 0.23, 95% CI 0.14-0.39, P < 0.001). There were no significant differences between GIC, resin-modified GIC, composite resin and MTA orifice barriers.

CONCLUSIONS

Placement of an orifice barrier over the root canal filling is effective in the prevention of coronal microleakage in vitro. Other parameters may also affect the effectiveness of orifice barriers, including thickness and duration of exposure to the oral environment. © 2023 Australian Dental Association.

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.

Quantitative Microbial Leakage Evaluation of Restorative Materials with/without Antibacterial Primer as an Intracoronal Barrier: An Ex Vivo Study

AIM

Aim of this research was to assess the microbial leakage of restorative materials with/without antibacterial primer as an intracoronal barrier.

MATERIALS AND METHODS

Fifty-five extracted single-rooted teeth were included in this study. The canals were cleaned, shaped, and obturated with gutta-percha and AH plus sealer at the established working length. After removing 2 mm of coronal gutta-percha, the teeth were incubated for 24 hours. The teeth were divided into groups according to the materials used as intracoronary orifice barriers as follows: • Group I: Clearfil Protect Bond/Clearfil AP-X • Group II: Xeno IV/Clearfil AP-X • Group III: Chemflex (glass ionomer) • Group IV: Positive control (no barrier) • Group V: Negative control (no barrier and inoculated with sterile broth) Sterile 2 chambers bacterial technique was used to assess the microleakage and Enterococcus faecalis was considered as a microbial marker. The percentage of samples leaked, the time taken for leakage, and the number of colony-forming units (CFUs) in the leaked samples were calculated and analyzed statistically.

RESULTS

There was no statistically significant difference found in bacterial penetration among the three investigated materials after 120 days of use as an intracoronal orifice barrier. This study can also infer that the leaked sample from the Clearfil Protect Bond showed the least mean number of CFUs (43 CFUs) followed by Xeno IV (61 CFUs) and glass ionomer cement (GIC) (63 CFUs).

CONCLUSION

This study concluded that all three experimental antibacterial primers performed better as intracoronal barrier. However, Clearfil Protect Bond with an antibacterial primer showed promising results as an intracoronal orifice barrier in reducing the number of bacterial leakages.

CLINICAL SIGNIFICANCE

The significance of intracoronal orifice barriers in the success of endodontic treatment depends on the ability of the materials to prevent microleakage. This helps clinicians to provide successful antibacterial therapy against endodontic anaerobes.

Treatment of cracked teeth: A comprehensive narrative review

Objectives

The term “cracked tooth” is used to describe an incomplete fracture initiated from the crown and progressing towards a subgingival direction. Despite the high prevalence of cracked teeth and their frequent association with symptoms and pulpal or periapical pathoses, there is still no consensus in the literature with regard to their restorative and endodontic management. Therefore, the aim of this narrative review was to evaluate the most relevant research and provide an up‐to‐date comprehensive overview regarding the treatment of cracked teeth.

Materials and Methods

An electronic literature search was carried out in MEDLINE (via Ovid), Embase (via Ovid), Scopus, and Web of Science as well as several “Grey literature” sources up to February 22nd 2022 using a combination of pre‐specified ‘free‐text' terms (keywords) and “subject headings.” The search process was supplemented by handsearching in relevant dental journals and reference lists. This narrative review focused on clinical follow‐up studies (observational or interventional studies, case series/reports), laboratory studies and systematic reviews written in English language that reported data on treatment of permanent cracked teeth. The selection of relevant studies was carried out by two reviewers (AK and DG) working independently in two consecutive stages: title/abstract screening and full‐text retrieval. Any discrepancies in the study selection were resolved by discussion between the reviewers.

Results

In total, 64 articles were selected for inclusion in this narrative review.

Conclusions

Cracked teeth with normal pulp or reversible pulpitis have exhibited high pulp and tooth survival rates by the provision of direct or indirect composite restorations. Besides, recent data favour monitoring, especially in the absence of symptoms or compromised tooth structure. When endodontic intervention is required, current evidence suggests that along with appropriate restorative management, outcomes of cracked teeth may be comparable to those of non‐cracked root filled teeth.

Effect of an Intraorifice Barrier on Endodontically Treated Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies

The main cause of unsuccess in endodontically treated teeth (ETT) is due to bacterial recontamination. The placement of an intraorifice barrier (IOB) has been proposed for preventing this event in cases that the restoration is in an inadequate condition, enhancing the possibilities for predictable long-term success in endodontic therapy. Objectives. To evaluate through a systematic review and meta-analysis if it would be necessary to place an IOB in ETT. Materials and Methods. The present review is in accordance with the PRISMA 2020 Statement and is registered in the Open Science Framework. Two blinded reviewers carried out a comprehensive search in four databases up to July 10^th, 2021: MEDLINE, Scopus, Embase, and Web of Science. Eligible studies were the ones which evaluated the use of an IOB in ETT in reducing microleakage with any material of choice and with any methods employed. Only in vitro studies published in English were included. Results. A total of thirty in vitro studies were included in the qualitative synthesis, and seven of those were included in the quantitative analyses evaluating the following materials: bioceramic cement, glass-ionomer cement (GIC), and resin-based composite (RBC). Most of the included studies placed an IOB at a 3 mm depth. Reduction in microleakage was observed when an IOB was placed, regardless of the material employed (p ≤ 0.01). Among the materials, GIC and RBC performed similarly (p > 0.05), with the bioceramic subgroup being statistically superior to the GIC subgroup (p ≤ 0.05). Conclusions. Although well-designed randomized clinical trials are required, the placement of an intraorifice barrier can significantly reduce microleakage in endodontically treated teeth, and the use of bioceramics as IOB seems to be the best available material for this purpose.

Coronal Bacterial Penetration after 7 days in class II endodontic access cavities restored with two temporary restorations: A Randomised Clinical Trial

The aim of this in vivo randomised clinical trial was to assess coronal bacterial penetration after placement of Cavit G and IRM temporary restorations in Class II endodontic access cavities. After completion of endodontic treatment, placement of an orifice seal and disinfection of the operating field, sterile cotton pellets were placed in the pulp chamber and the cavities were restored with Cavit G or IRM. After 7 days, coronal and proximal restoration thickness was measured by digital radiographs. Cotton pellet was evaluated by culture methods and polymerase chain reaction assay and bacterial species identified. Bacterial growth was observed in 5 of the 27 (18%) Cavit G samples and in 11 of the 27 (40%) IRM samples which was not significant. Coronal restoration thickness of 4-5 mm and proximal restoration thickness of more than 2.15 mm for Cavit G and 2.35 mm for IRM are recommended to prevent bacterial penetration over 7 days. Adequate restoration thickness is critical to prevent bacterial penetration.

An in vitro comparative evaluation of different intraorifice barriers on the fracture resistance of endodontically treated roots obturated with gutta-percha

AIM

To compare and evaluate the root reinforcement potential of four different intraorifice barriers: Mineral trioxide aggregate (MTA), resin-modified glass ionomer cement (RMGIC), fiber-reinforced composite (FRC), and nanohybrid composite (NC).

MATERIALS AND METHODS

Seventy-five mandibular premolars were decoronated to a standardized length, and prepared and obturated with gutta-percha and AH Plus sealer. Except for control specimens, the coronal 3-mm gutta-percha was removed and filled with different materials. The specimens (75) were divided into five groups (n = 15) on the basis of the intraorifice barrier material used. Group 1: MTA, Group 2: RMGIC, Group 3: FRC, Group 4: NC, Group 5: no barrier (control). Fracture resistance of the specimens was tested.

RESULTS

Fracture resistance of roots was significantly affected by the type of intraorifice barrier used and the following pattern was observed: RMGIC > FRC > NC > MTA.

CONCLUSION

Intraorifice barriers can be regarded as a viable choice to reduce the occurrence of postendodontic root fractures. Among the four tested materials, RMGIC showed the maximum reinforcement.

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents

OBJECTIVE

The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE; (2) Excite DSC; (3) Clearfil Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test.

RESULTS

At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil Protect Bond, AdheSE and Excite DSC showed similar behaviours, likewise similar to the Control group.

CONCLUSIONS

One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.

Intraorifice sealing ability of different materials in endodontically treated teeth: An in vitro study

Background:

Microbial contamination of the pulp space is one of the major factors associated with endodontic failure. Thus, in addition to a three dimentional apical filling a coronal seal for root canal fillings has been recommended.

Aim:

The present study was conducted to evaluate and compare the intra-orifice sealing ability of three experimental materials after obturation of the root canal system.

Materials and Methods:

Fourty single rooted mandibular premolars were decoronated, cleaned, shaped and obturated. Gutta-percha was removed to the depth of 3.5 mm from the orifice with a heated plugger. Ten specimens each were sealed with Light Cure Glass Ionomer Cement (LCGIC), Flowable Composite (Tetric N-Flow), and Light Cure Glass Ionomer Cement with Flowable Composite in Sandwich Technique along with a positive control respectively and roots submerged in Rhodamine-B dye in vacuum for one week. Specimens were longitudinally sectioned and leakage measured using a 10X stereomicroscope and graded for depth of leakage.

Results:

According to the results of the present study LC GIC + Tetric N Flow demonstrated significantly better seal (P < 0.01) than LC GIC. However there was no statistically significant difference in leakage (P > 0.01) between Tetric N-Flow and LCGIC+Tetric N-Flow groups.

Conclusion:

In the current study LCGIC+Tetric N-Flow was found to be superior over other experimental materials as intra-orifice barriers.

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.

Effect of bleaching agents on sealing properties of different intraorifice barriers and root filling materials

Objective: To evaluate the effect of intracoronal bleaching agents on the sealing properties of different intraorifice barriers and root filling materials. Study Design: The root canals of extracted human premolars (n=180) were prepared by using System GT rotary files and filled with either gutta-percha+AH Plus or Resilon+Epiphany sealer. In both groups, the coronal 3mm of root filling was removed and replaced with one of the following materials applied as intraorifice barriers (n=30/group): 1. ProProot-MTA; 2. Conventional Glass ionomer cement; and 3. Hybrid resin composite. In each subgroup, intracoronal bleaching was performed using either sodium perborate with distilled water or 35% hydrogen peroxide gel for 3 weeks. The leakage of specimens was measured using fluid-filtration and dye penetration tests. The data were analyzed statistically with One-way ANOVA, Repeated Measures t-test and Independent Samples t-test (p=0.05). Results: The fluid conductance values of the test groups were not influenced by the type of the bleaching agent, the intraorifice barrier, or the root filling material (all p>0.05). However, the extent of dye leakage was significantly affected by the type of intraorifice barrier material (p<0.05), which showed the following statistical ranking: glass ionomer cement > resin composite > ProRoot-MTA (p<0.05). Conclusions: The effect of 35% hydrogen peroxide gel or sodium perborate/distilled water on the sealing properties of tested intraorifice barriers and root filling materials varied conforming leakage assessment. These properties were not affected by using fluid filtration test, while the glass ionomer barrier showed the greatest amount of dye leakage in both gutta-percha and Resilon root-filled teeth.

Key words:Tooth Bleaching, root canal filling materials, glass ionomer cement, mineral trioxide aggregate, micro leakage

Effect of intra-orifice depth on sealing ability of four materials in the orifices of root-filled teeth: an ex-vivo study

Aim. To investigate the effect of orifice cavity depth on the sealing ability of Fusio, Fuji II, Fuji IX, and MTA“G”. Materials and Methods. Ninety-two canals in extracted mandibular premolars were prepared, obturated, and randomly grouped into 4 groups. Each group was subgrouped for a 2 mm and 3 mm orifice cavity depth (n = 10). The remaining roots were divided to serve as positive and negative controls (n = 6). Cavities of the 4 experimental groups were filled with the respective materials and subjected to methylene blue dye leakage. Linear leakage was measured in mm using a stereomicroscope. Statistical Analysis. Kruskall-Wallis test was used at P < 0.05, and t-test was done to compare 2 mm and 3 mm. Results. All tested materials leaked to various degrees. Significantly higher leakage score was found for Fuji IX, Fusio, Fuji II, and MTA “G” in a descending order, when the materials were placed at 3 mm depths. A significant difference was found in the leakage score between the 2 mm and 3 mm depths in all tested materials with the 3 mm depth showing a greater leakage score in all tested materials. Exception was in MTA “G” at 2 mm and 3 mm depths (0.551 mm ± 0.004 mm and 0.308 mm ± 0.08 mm, resp.). Conclusion. The null hypothesis should be partially rejected. Fusio and MTA “G” were affected by orifice cavity depth with regard to their sealing ability. MTA “G” had the least leakage when placed at 2 or 3 mm depths, and Fusio is the next when placed at 2 mm depth. Two millimeters orifice cavity depth is suitable for most adhesive orifice barrier materials.

Restoration of endodontically treated teeth review and treatment recommendations

Coronal restorations and posts can positively influence the long-term prognosis of teeth following root canal therapy. Final sealing the canal by placing an appropriate post and core will minimize leakage of oral fluids and bacteria into the periradicular area and is recommended as soon as possible after completion of root canal filling. Glass ionomer or MTA placed over the residual root canal filling after post space preparation may be effective to prevent bacterial leakage. A ferrule of 1-2 mm of tooth tissue coronal to the finish line of the crown significantly improves the fracture resistance of the tooth and is more important than the type of the material the core and post are made of.

Effect of glass-ionomer cement as an intra-canal barrier in post space prepared teeth: An in vitro study

Aim:

To evaluate the bacterial microleakage across remaining Gutta-percha in teeth prepared for post space with and without the use of an intracanal glass ionomer barrier.

Materials and Methods:

Forty freshly extracted intact human mandibular premolars with single canal were instrumented, obturated with Gutta-percha and AH plus sealer and post spaces were created. Teeth were assigned into experimental groups as follows: Group I – 3 mm of Gutta-percha, Group II – 4 mm of Gutta-percha, Group III – 3 mm of Gutta-percha with 1 mm of Vitrebond as barrier, Group IV – 4 mm of Gutta-percha with 1mm of Vitrebond as barrier. The roots were suspended in Rogosa SL broth and 50 μl of lyophilized Lactobacilli Casei was inoculated as the microbial marker. The mean days taken for the broth to turn turbid were tabulated. The values were statistically analyzed using one way ANOVA and Tukey's HSD test.

Results:

At the end of 64 days, the mean and standard deviation of the number of days for the broth to turn turbid was: Group I – 20.50, (SD - 3.96). Group II – 25.43, (SD - 4.83), Group III – 38.63, (SD - 9.36), and Group IV – 53.50, (SD - 11.15)

Conclusion:

Vitrebond could be used as an intracanal barrier to provide a superior coronal seal in teeth requiring post and core.

Endodontic update 2006

The past 10 years have witnessed more significant changes in the art and science of endodontics than the previous 100 years. This observation is no surprise, given that change is our only constant. The rate of change, however, has been anything but constant. The rate has accelerated so fast that all clinicians in the field of dentistry need a reliable source to guide us in what works. What works today in endodontics is the theme of this update. The discoveries and advancements in endodontic technology, instruments, and materials enable practitioners to achieve treatment outcomes that were previously considered unattainable. For example, in nonsurgical endodontic treatment, nickel titanium technology consistently can produce predictable radicular preparations that can be easily obturated. In nonsurgical re-treatment, the previous endodontic obturation attempt frequently can be removed and successfully re-treated largely because of enhanced vision and coaxial lighting from the operating microscope. Importantly, careful nonsurgical re-treatment usually can be accomplished without disruption to the existing restorations and without risk to ferrule integrity. In endodontic surgery underfilled foramina, and the isthmi between them, predictably can be connected and obturated with state-of-the-art miniature instruments. CLINICAL SIGNIFICANCE This article reviews the clinical endodontic breakthroughs encountered during the last decade and focuses on three primary topics: (1) finding canals; (2) following canals; and (3) finishing canals. Every day, dentists are faced with the interdisciplinary treatment planning question of to "save or not to save a tooth?" Dentists must routinely make the decision of whether to remove or restore the tooth based on biology, structure, function, esthetics, and value.(1) Occasionally, the endodontically treated tooth can be the weakest link in the restorative and esthetic sequence. This article examines the current state of endodontic technology, as well as the fundamentals of endodontic mechanics needed to achieve the most predictable endodontic outcome with the highest degree of success.

An In Vitro Assessment of the Sealing Ability of Resilon/Epiphany Using Fluid Filtration

The aim of this in vitro study was to compare the sealing ability of Resilon/Epiphany to gutta-percha and Roth or AH Plus sealers. Leakage of the obturated roots was measured using the fluid filtration technique. There were eight groups of 12 teeth each. Group 1: obturated with Resilon/Epiphany; group 2: obturated with gutta-percha/Roth, allowed to set for 3 wk; group 3: obturated with gutta-percha/Roth; group 4: obturated with Resilon/Epiphany using a single cone; group 5: obturated with Resilon cones without using primer/sealer (positive control); group 6: obturated with gutta-percha/AH Plus; group 7: same as group 6, but allowed to set for 8 h; and group 8: sealed on the outside with three layers of nail varnish (negative control). The results showed that only the positive control (group 5) leaked significantly more (p < 0.05) than the other groups. There was no effect of time on leakage. Resilon/Epiphany was no better than gutta-percha/Roth or gutta-percha/AH Plus at sealing root canals.

Sealing ability of three materials in the orifice of root canal systems obturated with gutta-percha

There were 130 single roots randomly assigned to one of 12 experimental or two control groups. Forty specimens each were sealed with 1, 2, 3, or 4 mm of Cavit, ProRoot MTA, or Tetric. After creation of a uniform orifice diameter, the smear layer was removed and the canal systems obturated using warm lateral compaction of gutta-percha (GP). GP was removed to the experimental depth, experimental materials placed in the orifice, and roots submerged in India ink in a vacuum flask. Specimens were demineralized and leakage measured using a 10x stereomicroscope and graded for depth of leakage by one calibrated, blinded rater. There was no significant interaction (p > 0.05) between test materials and orifice depths, nor main effect of orifice depth (p > 0.05). However, there was a statistically significant main effect of test materials with Tetric demonstrating a significantly better seal than Pro Root or Cavit (p < 0.0001) irrespective of orifice depth.

The ability of thiourea to scavenge hydrogen peroxide and hydroxyl radicals during the intra-coronal bleaching of bloodstained root-filled teeth

BACKGROUND

Hydrogen peroxide, an agent used in the intra-coronal bleaching of root-filled teeth for over a century, has been shown to diffuse from the pulp chamber to the outer root surface. Furthermore, it has been demonstrated that destructive hydroxyl radicals, the by-products of the bleaching process, have been detected on the external root surface. The control of such diffusion may be of importance in minimizing the risk of invasive cervical resorption (ICR) which has been linked to intra-coronal bleaching of discoloured root-filled teeth using hydrogen peroxide. The aims of the present in vitro study are to quantify the diffusion of hydrogen peroxide and hydroxyl radicals to the outer root surface following intra-coronal bleaching, and to evaluate the ability of thiourea incorporated into the bleaching protocol to scavenge residual hydrogen peroxide and hydroxyl radicals.

METHODS

Thirty-five single rooted premolar teeth with intact cementum at the cemento-enamel junction were used in this project. Thirty teeth were stained with red blood cells and root-filled with gutta-percha and AH26. The five unstained teeth were root-filled and constituted a negative control (Group 1). The stained teeth were divided equally into the following experimental groups and subjected to various intra-coronal bleaching regimes: Group 2--'walking bleach' with 20 microl 30 per cent w/w hydrogen peroxide; Group 3--20 microl 30 per cent w/w hydrogen peroxide and thermocatalytically activated; Group 4--20 microl acidified thiourea; Group 5--20 microl acidified thiourea and 20 microl 30 per cent w/w hydrogen peroxide; Group 6--20 microl acidified thiourea and 20 microl one per cent sodium hypochlorite; Group 7--20 microl acidified thiourea, 20 microl one per cent sodium hypochlorite and 20 microl 30 per cent w/w hydrogen peroxide. The reaction products of the bleaching process were quantified at the outer root surface using high performance liquid chromatography and electrochemical detection (HPLC-ECD).

RESULTS

Results showed that hydrogen peroxide used alone in Groups 2 and 3 was able to be detected at the outer root surface in 100 per cent of the samples, and that the presence of the hydroxyl radical generated in both groups was detected in equal amounts (P < 0.05). When thiourea was incorporated into the bleaching protocols in Groups 5-7, it was shown to scavenge both hydrogen peroxide and hydroxyl radicals to a significant degree (P < 0.05).

CONCLUSIONS

Acidulated thiourea is an effective scavenger of residual hydrogen peroxide and hydroxyl radicals generated during the intra-coronal bleaching of bloodstained root-filled teeth.

Effect of Orifice Plugs on Periapical Inflammation in Dogs

Gutta-percha (G) and sealer do not resist coronal leakage. In this study, the effect of orifice plugs using dentin-bonding/composite resin(C) or IRM on coronal leakage was evaluated in vivo. Sixty-one premolar roots in three beagle dogs were instrumented and filled with G and AH 26(S), or G alone. The coronal 2 mm was replaced with C or IRM, or left untreated. The access cavities were kept open for 8 months, the dogs were killed and the periapical regions of the roots were histologically examined. Periapical inflammation was observed in 89% of the group without plugs, but in those with plugs, the occurrence was decreased to 39% (C + G + S), 38% (IRM + G + S) and 58% (C + G), respectively. Furthermore, severe inflammation was observed in 50% of the former group but only 0 to 17% of the latter. The substantial reduction in apical periodontitis by the use of coronal plug underscores the clinical importance of providing an additional barrier to coronal leakage in comparison to that provided by gutta-percha and sealer alone.

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.

The Effect of Thermocycling on a Colored Glass Ionomer Intracoronal Barrier

The purpose of this study was to evaluate the effect of thermocycling on a colored glass ionomer intracoronal barrier used for the prevention of microleakage. Thirty single canal premolars were decoronated, standardized in length, instrumented, obturated, and randomly assigned to three groups. Group 1 received a 1 mm intracoronal barrier of Triage glass ionomer, group 2 received a 2 mm Triage barrier, and group 3 received no barrier. After incubation for sealer set, teeth were thermocycled. Microleakage was measured using the fluid transport model. Groups 1, 2, and 3 demonstrated 1.68 mm, 0.60 mm, and 23.24 mm of movement, respectively. Using ANOVA and Student-Neumann-Keuls, group 3 leaked significantly more (p < 0.05) than groups 1 and 2, with no difference between groups 1 and 2. A 1 or 2 mm intracoronal barrier of Triage significantly reduced coronal microleakage in thermocycled endodontically treated teeth.

Adhesive Dentistry and Endodontics: Materials, Clinical Strategies and Procedures for Restoration of Access Cavities: A Review

The complexity of restorative dentistry has increased greatly in recent years, with the myriad of products used in "adhesive dentistry." So too has the "simple" matter of restoring access cavities after completion of endodontic treatment. This review discusses current methods of "bonding" to tooth structure, ceramic materials, and metals, with emphasis on those aspects that are important to endodontics. Specific materials, procedures and major decision making elements are discussed, as well as how to avoid problems in compatibility between endodontic and restorative materials.

The effect on coronal leakage of liquid adhesive application over root fillings after smear layer removal with EDTA or Er:YAG laser

OBJECTIVE

To evaluate coronal microleakage in filled root canals that received different biomechanical preparations and application of liquid adhesives over the root filling and the pulp chamber walls.

STUDY DESIGN

Root canals of 94 extracted canine teeth were filled after being biomechanically prepared with 1% sodium hypochlorite and divided into 3 groups. In 2 groups attempts were made to remove the smear layer with either 17% EDTA or Er:YAG laser irradiation (10 Hz, 250 mJ input, 112 mJ output). Liquid adhesive (Super Bonder and Single Bond adhesive) was applied and the teeth were immersed for 90 days in India ink.

RESULTS

Statistically significant differences were found for the different preparations, the use of liquid adhesives, and the different liquid adhesives. The use of Er:YAG laser, EDTA, and the liquid adhesive reduced coronal microleakage (P < .01).

CONCLUSIONS

Because of the risk of coronal microleakage, endodontically treated teeth should be restored as quickly as possible.

Sealing Ability of One-Up Bond and MTA With and Without a Secondary Seal as Furcation Perforation Repair Materials

This study investigated the ability of One-Up Bond alone and mineral trioxide aggregate (MTA), with and without a secondary seal of One-Up Bond or SuperEBA to seal saucer-shaped perforation defects in human molars. Cusps were removed, roots were amputated, and endodontic therapy completed on 40 extracted teeth. A cylindrical hole was made in each tooth from the furcation area to the chamber, into which a section of steel tubing was cemented. Intracoronal saucer-shaped defects were created over the perforation. The teeth were restored with MTA, One-Up Bond, or MTA with a secondary seal of One-Up Bond or SuperEBA. The integrity of the seal was evaluated by fluid filtration. MTA alone leaked significantly more than One-Up Bond or MTA with either secondary seal at 24 h. At 1 month, MTA, MTA plus One-Up Bond, and One-Up Bond alone were equivalent.

In vivo analysis of post space sealing with different adhesive materials

This in vivo study analyzed the sealing ability of two adhesives in post spaces, cyanoacrylate (Super Bonder® - Henkel Loctite Adesivos Ltda., Itapevi, SP, Brazil) and ScotchbondTM Multi-Purpose (3M Dental Products, St. Paul, MN, USA), testing the hypothesis that their use would result in a decreased leakage through the remaining filling material. Forty extracted premolars (80 root canals) of dogs were used. The root canals were cleaned, shaped and filled by the lateral condensation technique using Sealer 26TM. The post space was created removing two thirds of the filling material within the root canal. The canals were randomly divided in three groups, which were treated as follows: Group A received the ScotchbondTM Multi-Purpose adhesive system; for Group B the cyanoacrylate adhesive, Super BonderTM, was employed; and no adhesive was applied into the post space for Group C (control group). A glass ionomer provisional restoration was placed allowing the sealer to set for 72 hours. Then the restoration was removed and the root canal was exposed to the oral environment for 45 days. The dogs were then killed and their jaws were removed. The post spaces were filled with India ink and the teeth were restored for 96 hours. Afterwards, the teeth were extracted and the roots were sectioned at the furcation for allocation to their specific groups. The teeth were turned transparent and the quantitative analysis of leakage was performed using light microscopy. The results showed no significant differences between groups, rejecting the initial hypothesis. Leakage occurred in a great extent in all specimens. Therefore, sealing post spaces with the adhesives used in this study was not an effective method to prevent microleakage.

An assessment of microbial coronal leakage of temporary filling materials in endodontically treated teeth

This in vitro study evaluated the microbial leakage of Cavit, IRM, and Dyract when used as temporary filling materials after root canal treatment. The degree of coronal leakage was assessed by using a microbiological marker consisting of Streptococcus faecalis and Candida albicans. For each of the two organisms, a set of 15 maxillary premolars were prepared chemomechanically and obturated with thermoplasticized gutta-percha. A 3.5-mm thick layer of one of the three temporary filling materials was inserted in the access cavities of the teeth from each group (each group was compromised of five teeth). The control teeth (four positive and four negative) lacked any filling material over the gutta-percha, whereas the orifice and the apical foramen of the negative control were completely sealed with nail polish. Each tooth was placed in a well of a 24-well tissue culture plate and embedded in trypticase soy broth and 0.5% Bactoagar. An organism suspension was inoculated in the access cavity, and microbial penetration was detected as an increase in turbidity of the broth. At the end of 30 days, the results showed that all positive control teeth leaked within 1 week, whereas those that served as negative control remained uncontaminated throughout the test period. With both organisms, IRM started to leak after 10 days, whereas Cavit and Dyract leaked after 2 weeks.

In vitro bacterial penetration of endodontically treated teeth coronally sealed with a dentin bonding agent

This study evaluated the effectiveness of a dentin bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).