Sealing ability of intermediate restorations and cavity design used in endodontics

Temporary filling materials are used in endodontics to prevent contamination of the root canal system during intertreatment visits. Recently, a new composition resin (TERM) has been introduced as an interim restoration in endodontics. The purpose of this investigation was to evaluate the efficacy of this resin as an interim restoration and possible effect of access cavity design with respect to its sealing ability compared with other temporary restorative materials. Sixty human teeth were divided into two categories, and two types of access cavities were prepared, namely tapered access with walls divergent toward the occlusal surface and straight access with parallel walls. The prepared teeth from each category were divided into three subgroups of ten each to receive Cavit (group I), IRM (group II), or TERM (group III). After the fillings were placed, the teeth were transferred into a humidor where they stayed for 24 hours. The teeth were then thermocycled. Each group was thermocycled for 2 hours at 1 minute intervals at 60 degrees C and 4 degrees C. Then the teeth were sealed with a compound and coated with two layers of clear varnish, with the exception of cavity margins. Each occlusal surface was immersed in a vial containing silver nitrate. The teeth were sectioned longitudinally, and the degree of dye penetration was evaluated under a dissection microscope according to set criteria. Our findings demonstrated that design of cavity preparation was not a functional parameter in leakage pattern. Results indicated that Cavit had the best sealing ability whereas IRM showed the maximum dye penetration.     

A comparative study of four coronal obturation materials in endodontic treatment.

The aim of this study was to compare, in vitro, the ability of temporary versus permanent materials to seal the access cavity. Eighty human maxillary single-canal teeth were prepared biomechanically and obturated with gutta-percha and an endodontic cement AH Plus, using the warm vertical compaction technique. All access cavities were sealed with 1 of 4 materials (Cavit, Fermit, Tetric, or Dyract). Microleakage was assessed by methylene blue dye penetration. The teeth were submitted to 100 thermocycles, with temperature varying from 0 degree to 55 degrees C. The greatest degree of leakage was observed with the temporary materials (Cavit and Fermit). There was a significant difference (p < 0.05) in leakage between all materials except between Dyract and Tetric. This suggests that it may be more prudent to use a permanent restorative material for provisional restorations to prevent inadequate canal sealing and the resulting risk of fluid penetration.     

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.     

Bacterial microleakage of Cavit, IRM, and TERM.

In this in vitro study, a model system was developed and tested to evaluate the sealing ability of temporary restorative materials used in endodontic access preparations. The materials studied, Cavit, IRM, and TERM, were tested on 40 premolars against a known bacterial species, Streptococcus sanguis. The leakage of bacterial cells was checked 4 and 8 days after initial immersion in the culture. Thermocycling was introduced on the fourth day. After 8 days the cement thicknesses were measured after the teeth had been longitudinally sectioned. Before and after thermocycling, IRM was less leakproof than Cavit (p < 0.05) and TERM (p < 0.05). Thermocycling aggravated percolation in the case of IRM, and decreased the tightness of Cavit, whereas TERM remained leakproof. The thicknesses were as follows: Cavit, 3.73 mm; IRM, 3.45 mm; and TERM, 5.49 mm. There was no statistically significant relationship between thickness and tightness.     

Leakage in roots coronally sealed with different temporary fillings

This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.     

Microleakage of temporary restorations in complex endodontic access preparations

The microleakage allowed by three temporary restorative materials used for the sealing of teeth with both endodontic access and multisurface cavity preparations was measured and evaluated. Extracted human incisor, canine, and premolar teeth with extensive carious involvement were prepared and restored with either Cavit, IRM, or TERM. Microleakage was measured by a fluid filtration technique at various time intervals and after thermal stress. The results indicated that the TERM restorations provided excellent seals and were statistically superior to Cavit and IRM for restoring complex endodontic access preparations. The IRM restorations demonstrated significantly greater microleakage after thermal stress, while the Cavit restorations were deemed clinically unacceptable because of extensive cracks, expansion, and extrusion from the tooth preparations. These defects were not observed with the IRM and TERM restorations.     

A microleakage study of temporary restorative materials used in endodontics

The purpose of this study was to quantitatively evaluate the sealing properties of various temporary restorative materials used in standard endodontic access preparations by using a newly introduced fluid filtration method. The materials tested were Cavit, Cavit-G, TERM, glass ionomer cement, zinc phosphate cement, polycarboxylate cement, and IRM. Extracted human incisor, canine, and premolar teeth were used, and each tooth served as its own control by testing for microleakage prior to access preparation. Following access preparation, cotton pellets were placed in the pulp chamber so that the space remaining for the restoration was 4 mm. Immediately after placement of the restoration, the teeth were immersed in Ringer's solution and incubated at 37 degrees C. Microleakage was measured after various time intervals. The results indicated that Cavit, Cavit-G, TERM, and glass ionomer cement provided leakproof seals during the 8-wk testing period, while leakage was observed in 4 of the 10 teeth restored with zinc phosphate cement. IRM and polycarboxylate cement were the least effective of the materials tested for preventing microleakage.     

Microleakage between endodontic temporary restorative materials placed at different times.

Occlusal endodontic access preparations are occasionally made in teeth without removing the original restoration. However, microleakage between restorative materials that are placed at different times has not been extensively studied. Therefore, our objective was to compare microleakage at three areas: between an access opening restorative material and the cavity wall; between an additional material placed later to patch a secondary opening in the first restorative material and the original restorative material itself; and between the secondarily placed material and the cavity wall. Standard endodontic access preparations were made in 120 noncarious, nonrestored crowns of extracted human molars. These teeth were divided into six experimental groups. Another four molars were controls. The endodontic access cavities were restored with either IRM or amalgam as the primary restorative material. After 14 days, half of the primary restorations was removed, and this defect was filled with a secondary restorative material: IRM, Caviton, or a double seal of Caviton and IRM. Microleakage was measured linearly as the extent of basic fuchsin dye penetration under a stereomicroscope after thermal cycling (5 degrees and 55 degrees C for 100 cycles) and tooth sectioning. Wilcoxon signed-rank test was used for statistical analysis. Results indicated significantly less microleakage between primary and secondary restorative materials placed at different times than microleakage between primary temporary restorative materials and the access cavity wall, regardless of the type of primary restorative material used (IRM or amalgam).     

Microleakage of temporary endodontic restorations in teeth restored with amalgam

Microleakage of seven temporary restorative materials was evaluated in endodontic access preparations made in teeth restored with amalgam. Ten teeth were used for each of the seven materials: Cavit, Cavit-G, TERM, zinc phosphate cement, polycarboxylate cement, glass ionomer cement, and IRM. A class I amalgam was placed in the occlusal surface of each experimental tooth and an endodontic access preparation was made entirely within the amalgam. Then the access preparation was restored with one of the temporary restorative materials, and microleakage was evaluated using a fluid filtration technique. The amount of microleakage was quantitated by measuring the fluid flow at 15 min, 1 h, 24 h, 1 wk, and 2 wk after insertion of the temporary restoration. Cavit, Cavit-G, TERM, IRM, and glass ionomer cement all provided excellent seals while zinc phosphate cement and polycarboxylate cement provided less effective seals.     

A laboratory study of coronal microleakage using four temporary restorative materials

AIM: The aim of this study was to compare the sealing abilities of Fermin and Canseal with the more popular temporary coronal filling materials, Cavit and Caviton. METHODOLOGY: Standardized access cavities were prepared in 160 intact human permanent molar teeth. They were divided into five groups consisting of 32 samples. The teeth were restored using one of the temporary filling materials, namely: Fermin, Canseal at two powder to liquid ratios, Caviton and Cavit. Thermal cycling and/or load cycling were applied on the samples. Assessment of microleakage utilized methylene blue dye penetration. Grading of the microleakage pattern was from 1 to 3, with 3 providing the best seal. Results were analyzed using two-way anova and by Fisher's PLSD post hoc test (P < 0.05). RESULT: Microleakage along Fermin, Caviton and Cavit samples did not go beyond Leakage Grade 2. Dye penetration into these materials was noted. This was not observed in the two groups of Canseal tested. However, the two groups of Canseal exhibited total leakage notably after being subjected to thermal cycling. There was a statistically significant difference in the microleakage scores obtained between the materials and conditions tested (P < 0.0001). CONCLUSION: Fermin was found to exhibit the best seal amongst the four materials tested followed by Caviton, and Cavit. Thermal cycling influenced the seal of certain types of temporary filling materials more than load cycling.     

Experimental model: dye penetration of extensive interim restorations used during endodontic treatment while under load in a multiple axis chewing simulator

The purpose of this study was to design an experimental model that allowed extensive endodontic interim restorations to be tested for dye penetration while under simulated masticatory load. Extracted premolar teeth had standardized mesio-occluso-distal cavities prepared, and the root canals were instrumented. A cotton wool pellet was placed in the pulp chamber, and the cavities were restored with Cavit, IRM, Ketac-Fil Plus, Ketac-Silver, or composite resin (Z100). They were subjected to the equivalent of 3 months of clinical load while exposed to methylene blue dye. Results of this study could not support IRM as a suitable interim endodontic restorative material to use in extensive cavities. The dye penetration in the Ketac-Fil Plus and Ketac-Silver specimens was not predictable, and the results suggested Cavit and Z100 composite resin require further investigations as potentially useful materials for this purpose.     

Assessment of coronal microleakage of three materials used in endodontically treated teeth

This study compared the coronal microleakage of three restorative materials used to seal the access cavity in root treated teeth. Thirty six teeth were prepared and three experimental groups were obturated and the access cavity filled with different materials; Group A--Intermediate Restorative Material, Group B--Fuji II and Group C--Dyract AP. Microleakage was assessed by Indian ink penetration. The mean coronal dye leakage for Group A was 0.895 mm, for Group B 1.914 mm and for Group C 3.245 mm. There was significantly (p < 0.05) more dye leakage in teeth restored with Dyract AP compared to those with Fuji II or IRM.     

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目的比较并评价3种不同暂封材料的冠部封闭效果。方法收集2011年1月至2012年5月于佛山市禅城区向阳医院因正畸或牙周病拔除的完整成人单根前磨牙60颗,备洞开髓后随机分为3组,每组20颗,分别用Clip、CavitG、氧化锌丁香油酚黏固剂（ZOE）3种暂封材料充满窝洞,经封闭处理后浸入2％亚甲蓝溶液染色,在暂封7d和14d时取出每组各10颗牙齿,顺牙长轴近远中向纵向剖开,观察染料渗入最大长度,并以此来评估3种暂封材料的冠部封闭效果。结果7d时Clip组和CavitG组封闭效果均优于ZOE组（P〈0．05）,14d时Clip组封闭效果优于其他两组（P〈0．05）。结论Clip是一种较好的根管治疗髓腔暂封材料。     

In vitro study to compare the coronal microleakage of Tempit UltraF, Tempit, IRM, and Cavit by using the fluid transport model

An adequate coronal seal is critical for the success of root canal therapy. The purpose of this study was to assess and compare the coronal microleakage of 4 temporary filling materials used to seal the access cavity in root canal treated teeth. Standardized access cavities were prepared in 55 extracted human, single canal teeth. They were instrumented by using a crown-down method to a size 45 file. The smear layer was removed with a 1-minute soak with 17% ethylenediaminetetraacetic acid followed by a 10-minute soak with 5.25% NaOCl and dried with paper points. All roots were obturated with gutta-percha and AH Plus sealer by using the continuous wave of condensation technique. The teeth were randomly divided into 4 groups of 10 teeth, with the remaining teeth serving as positive and negative controls. The access openings of the teeth in the experimental groups were filled with 4 mm of Cavit, IRM, Tempit, or Tempit-Ultra-F. All teeth were stored in 100% humidity at 37 degrees for 10 days, allowing sealer to set before testing. After thermocycling for 500 cycles (5 degrees C-55 degrees C), microleakage was measured by using the fluid transport model at 10 psi. All materials tested leaked. Kruskal-Wallis and Mann-Whitney U analysis indicated significantly less leakage (P < .05) with Tempit UltraF compared with Cavit and IRM. There were no statistically significant differences between Tempit Ultra-F and Tempit or between Cavit, IRM, and Tempit.     

An in vitro evaluation of four materials as barriers to coronal microleakage in root-filled teeth

AIM: To assess the ability of IRM, Coltosol, Vidrion R and Scotch Bond to seal the pulp chamber following root-canal treatment. METHODOLOGY: Root-canal treatment was completed on 100 extracted human mandibular molars. The teeth were divided into five groups of 20 teeth each, one group for each barrier material and one control group without barrier material. Two millimetres of the restorative material was placed on the pulp chamber floor. The teeth were thermocycled and evaluated for microleakage using India ink. Specimens were cleared and measurements made to the maximum point of dye penetration. The mean dye penetration for each group was compared by the Kruskal-Wallis test. RESULTS: All groups showed dye penetration. Coltosol and IRM sealed significantly better than the other groups, preventing the coronal leakage in 84% and 75% of the specimens, respectively. Scotch Bond exhibited the highest leakage (54% of specimens with dye penetration), which did not differ significantly from the positive control group (62% with dye penetration). CONCLUSIONS: None of the materials were able to prevent microleakage in all specimens. Vidrion R and Scotch Bond demonstrated the poorest results when used as barriers to coronal microleakage, whilst IRM and Coltosol were significantly better in preventing microleakage.     

Comparative in vitro coronal microleakage study of new endodontic restorative materials

Complete sealing of endodontic access openings between appointments and after completion of therapy is an essential element in achieving endodontic success. Recently, two new products for use as temporary restorative materials, TERM and Dentemp, have become available. The purpose of this study was to compare in vitro the sealing ability of Cavit, Cavit-G, Cavit-W, and IRM-Caps, with TERM, Hard-TERM, and Dentemp. Standard access cavities were prepared in 144 intact extracted human teeth. They were equally and randomly distributed into seven groups, and their access openings were temporized. Specimens were submitted to thermocycling (5 to 55 degrees C) for 7 days and stained with silver nitrate. The teeth were split in half, and the greatest depth of dye penetration at the tooth surface was recorded. TERM exhibited the least leakage, while Hard-TERM demonstrated the greatest leakage, at the tooth-restoration interface.     

Microleakage of different types of temporary restorative materials used in endodontics

A temporary filling should seal the endodontic access cavity to avoid reinfection of the root canal system during endodontic treatment. The aim of this study was to evaluate the marginal seal of four temporary filling materials in endodontic access cavities in vitro, using the dye penetration method. Endodontic access cavity preparations were in 50 incisor and 50 molar noncarious nonrestored crowns of extracted human teeth. The coronal access of 10 teeth per group were filled with Coltosol, Algenol, IRM, Fermit or Fermit-N. After storing the teeth in demineralized water for 48 hours, they were immersed in 2% methylene blue dye for 24 hours. All the teeth were sectioned longitudinally and the linear depth of dye penetration was evaluated under a stereomicroscope. There was no significant difference in the microleakage observed in the high elasticity light-cured resin composite (Fermit) versus the low elasticity light-cured resin composite (Fermit-N) groups (p > 0.05).     

The effect of storage time on the degree of dye leakage of root-end filling materials

The quality of the apical seal obtained by root-end filling materials generally has been assessed by the extent of dye penetration. Most investigators have allowed the root-end filling materials to set before they are tested. The purpose of this study was to evaluate if storage time had any influence on the amount of dye leakage. Seventy extracted single rooted human anterior teeth were used. After removal of their anatomical crowns, the roots were instrumented, filled with gutta-percha and Roth's sealer, and subjected to test conditions. The roots were coated with two coats of nail polish. Root ends were resected and class I cavities prepared. Sixty class I root-end cavities were filled with with either amalgam, super EBA, or IRM (20 each). Ten roots in each group were placed immediately into India ink for 48 h, the other 10 were stored for 24 h before placement into the ink. Ten roots (five per group) were used as positive (gutta-percha, no sealer) and negative (bone wax) controls. The roots were then demineralized, linear dye leakage was measured, and the data were evaluated statistically using ANOVA. Super EBA, and IRM showed significantly less dye leakage than amalgam (P<0.0001). No significant difference existed between Super EBA and IRM. Storage time had no significant influence on the amount of dye leakage observed in this study.     

Cervical canal leakage after internal bleaching.

The effects that walking bleach procedures had on root canal filling leakage and the extent of dentinal penetration were studied. Forty teeth were divided into four groups: 1--GP, set sealer, no base; 2--GP, set sealer, 2-mm Cavit base; 3--GP, unset sealer, no base; and 4--GP, unset sealer, 2-mm Cavit base. All were bleached for 7 days, fresh bleach was added for another 7 days, then methylene blue dye was placed for 5 days. The extent of dye penetration apically along the root canal filling and through the dentinal tubules was evaluated. The results indicate that 2 mm of Cavit was sufficient to significantly reduce linear leakage and dentinal penetration. The Cavit should be placed to a level slightly coronal to the facial cementoenamel junction. Teeth with cemental defects demonstrated greater perpendicular dye penetration in the areas of the defects than those with intact cementum. The data from this study suggest the use of a base material over gutta-percha in clinical practice prior to internal walking bleach procedures.     

Microleakage of five temporary endodontic restorative materials

This study evaluated the ability of five interim endodontic restorative materials to resist microleakage. Sixty extracted human molars were prepared for initial endodontic therapy via occlusal access preparations. After removal of the pulpal tissue, a cotton pellet was placed in the pulp chamber. The access preparations were sealed with one of the following materials or combinations: TERM, Cavit, IRM, Ketac-Silver, or a IRM-Cavit "sandwich" restoration. The specimens were thermocycled for 24 hours (800 cycles), immersed in methylene blue dye for 4 hours, sectioned, and evaluated under a microscope for microleakage. TERM, Cavit, and the IRM-Cavit "sandwich" had virtually no microleakage, while Ketac-Silver and IRM exhibited gross microleakage.