Coronal microleakage of three temporary restorative materials: an in vitro study

The sealing properties of three temporary restorative materials, Cavit, IRM, and a polycarboxylate-based cement, Ultratemp Firm, were investigated in vitro. Standardized access cavities were prepared in 45, intact, extracted, human molars. The teeth were randomly assigned to three groups and the access openings filled with one of three temporary filling materials. In five teeth (negative control), no restorative material was placed but the preparations were coated entirely with sticky wax. The five teeth of the positive control group had no restorative material and no sticky wax applied. After thermocycling for 500 cycles (5-55 degrees C), the experimental teeth were dipped in molten sticky wax to the CEJ. The coronal enamel was subsequently coated with two layers of nail varnish, leaving an area of 1 mm around the filling material uncovered. The samples were then immersed in 2% methylene blue dye solution for leakage assessment. The teeth were sectioned and the greatest depth of dye penetration was recorded. Positive control sections exhibited complete dye penetration, whereas negative controls had none. There was no statistically significant difference in marginal leakage between Cavit, IRM, and Ultratemp Firm (p > 0.05). All materials leaked at the interface material-dentin, whereas some IRM specimens absorbed the dye into the bulk of the material.     

Dye penetration in dry and water-filled gaps along root fillings

AIM: The aim of this study was to investigate the influence of hydration in voids along root fillings on methylene blue penetration. METHODOLOGY: A total of 80 human root canals were prepared using a step-back technique and filled with a zinc oxide based sealer and gutta-percha. Leakage along the fillings was measured by a transport fluid model and classified into three categories: gross leakage (GL), slight leakage (SL) and no leakage (NL). Specimens with NL and SL were immersed into methylene blue (MB) 2% for 24 h (group I). Specimens with GL which had wide gaps filled with water were randomly divided into two groups (II, III). Transport air was applied to remove water from gaps only in specimens of group III. All tested specimens from groups II and III were also immersed into MB 2% for 24 h. Each specimen was then split longitudinally and linear measurements of dye penetration were recorded. RESULTS: Group III (with dry gaps) showed significantly more dye penetration than group II. No significant difference was found between group I and group II. CONCLUSIONS: Methylene blue penetrates along root fillings more easily in dry gaps than in water-filled gaps.     

Apical leakage following root canal dressing with calcium hydroxide

Abstract The purpose of this study was to analyse the apical leakage in teeth filled by the lateral condensation technique following medication with calcium hydroxide. One hundred and twenty extracted human teeth were biomechanically prepared by using exclusively reaming motion with files up to #40. Half of the teeth received a calcium hydroxide dressing for 3 days. The medication was removed by irrigation and reaming motion with files #40 up to #70. The teeth were divided in 6 experimental groups, according to the dimension of the utilized instrument. The root canals were filled and posteriorly the teeth were placed into a 2% methylene blue dye solution inside a flask, which was attached to a vacuum pump. Leakage was measured linearly, and the results showed significantly (p<0.01) less leakage in the experimental groups that received calcium hydroxide dressings than in the control groups. The results persisted even after the removal of 300 of dentin from the root canal dentinal walls.     

Dye extraction results on bacterial leakproof root fillings

This study was designed to assess and compare the sensitivity and sealability results between bacterial leakage and dye extraction. Eighty mandibular incisors were prepared, and their roots were filled as follows (n = 20): G1, lateral condensation; G2, System B; and G3, Thermafil system. All teeth were mounted in a 2-chamber apparatus, and the coronal access was exposed to human saliva for 100 days. The remaining bacterial leakproof specimens were randomly assigned to create 3 new and equal groups (n = 10). These bacterial leakproof specimens were submitted to a dye extraction setup. Each specimen was placed into a plastic vial with 5 mL of 2% methylene blue for 48 hours. After storage, the specimens were rinsed with tap water and dissolved in nitric acid. A sample of 100 microL of the supernatant from each specimen was analyzed in a UV-Visible spectrophotometer to determine the amount of methylene blue leakage. The log-rank test showed no significant difference in the bacterial leakage pattern among the groups (P > .05). In the dye extraction analysis, Kruskal-Wallis H test was unable to detect significant differences among all experimental groups (P > .05). The 3 filling techniques displayed similar leakage for both leakage models. Moreover, the present study demonstrated that all bacterial leakproof specimens leaked when submitted to the blue methylene extraction model.     

Electrical and dye leakage comparison of three root-end restorative materials.

OBJECTIVE: The purpose of this study was to assess three modern root-end restorative materials with electrical and dye leakage tests. METHOD AND MATERIALS: Thirty-three human canine teeth were prepared and filled with gutta-percha and sealer. Stainless steel rods were inserted into the root canals as anodes, and the teeth were varnished. The apical 3 mm of each tooth was resected, and 3-mm root-end preparations were made ultrasonically. Mineral trioxide aggregate, Super EBA, and IRM were used to restore 10 teeth each, and three teeth were varnished as controls. Following 24 hours' setting in blood, the specimens were placed in 1% potassium chloride electrolyte, and leakage was recorded electrically for 70 days. The teeth were then submerged in methylene blue dye for 72 hours, sectioned longitudinally, and scored for leakage by six examiners. RESULTS: In both tests, the mineral trioxide aggregate restorations leaked significantly less than the IRM and Super EBA restorations. Super EBA showed significantly less leakage than did IRM restorations in the electrochemical test but not in the dye leakage experiment. The teeth sealed with mineral trioxide aggregate performed similarly to the varnished negative control teeth. CONCLUSION: The results of this study indicated that mineral trioxide aggregate provides a superior seal in root-end-restorations.     

Effect of calcium hydroxide dressing on seal of permanent root filling

Abstract Low apical leakage along root fillings following an application of calcium hydroxide was reported in a few methylene blue dye penetration studies. It has been found recently that methylene blue is decolored by calcium hydroxide, indicating that the short penetration of methylene blue may not be due to a tight seal only. Of the 80 roots of human maxillary central incisors used in this study, 40 roots (group 1) received calcium hydroxide root canal dressing whereas another 40 roots (group 2) did not. All the roots were then obturated with gutta-percha and Tubli-Seal sealer. Leakage along 20 filled roots in each group was measured using a modified fluid transport model at 48 h, 2, 4, 8 and 16 weeks after obturation; whereas leakage of another 20 filled roots in each group was measured using dye penetration with 1% methylene blue. Using the fluid transport model, no significant difference was found between the two groups at any time interval (P=0.4847, 0.3875, 0.9490, 0.4786, 0.9148 respectively after 48 h, 2, 4, 8 and 16 weeks); using the methylene blue penetration method, leakage in group 1 (with root canal dressing) was significantly less than that in group 2 (without root canal dressing) P=0.0374). The contradiction in results from the different models indicated that problems existed with the models.     

Comparison of the root-end sealing ability of MTA and Portland cement

The aim of this study was to compare the in vitro sealing ability of ProRoot MTA, ProRoot MTA (Tooth-Coloured Formula), ordinary Portland cement and white Portland cement when used as root-end filling materials. Twenty-four single-rooted human premolars were prepared and obturated using standard techniques, then retrofilled with the test materials. The prepared teeth were immersed in 1% methylene blue dye for 72 hours and then assessed for dye leakage. The depth of dye penetration was measured and expressed as a percentage of the length of the retrofilling. Data was analysed using ANOVA and Fisher's Least Significant Test (LSD) (p < 0.05). None of the teeth in any of the test groups showed leakage beyond the retrofillings. Given the low cost and apparently similar sealing ability of the cements, it is reasonable to consider Portland cement as a possible substitute for MTA as a root-end filling material. However, further tests, especially in vivo biocompatibility tests, need to be conducted before Portland cement can be recommended for clinical use.     

Clinical, radiographic, SEM evaluation and assessment of microleakage of Class II composite restorations

The influence of incremental or bulk filling techniques, and reapplication of unfilled resin (impregnation) to the margins with an enamel bonding agent, on marginal adaptation was evaluated in Class II composite restorations by clinical, radiographic, scanning electron microscope (SEM) and dye penetration techniques. Cavities were prepared in 80 extracted permanent posterior teeth. All cavity walls were treated with polyacrylic acid for 10 seconds. The enamel was etched for 1 minute, rinsed, dried, and lined with Scotchbond. Forty cavities were filled by increments of P30 and 40 cavities in bulk. The margins of the restorations of 20 teeth in each group were re-etched for 30 seconds and Concise Enamel Bond reapplied. The clinical scores were excellent for all restorations. Radiographic examination showed twice as many bubbles in the incrementally filled restoration than in the group filled in bulk. In 53 teeth, a radiolucent area between the dentin and the restorative material was found. After sectioning, this area was found to correspond to a hard material. The SEM revealed excellent margins in the groups of teeth that were impregnated with an unfilled resin, whereas 13 teeth without impregnation showed defective margins. The dye penetration, as a test for marginal leakage, was minimal at the occlusal surface of all teeth. At the cervical surface, 10.5% of the impregnated teeth showed severe dye penetration compared to 18% of the nonimpregnated teeth. No correlation was found between dye penetration at the cervical surface and the thickness of the residual enamel in this area.(ABSTRACT TRUNCATED AT 250 WORDS)     

Marginal leakage of Gallium Alloy root-end fillings: an in-vitro assessment

The sealing ability of amalgam and Gallium Alloy Gallium Filling (GF) root-end fillings was evaluated in vitro using a highly uniform collection of sheep incisor roots. Following ultrasonic canal debridement and orthograde obturation with gutta-percha and sealer, root-end cavities were prepared in 100 roots and filled with amalgam (50 teeth) or Gallium Alloy GF (50 teeth). Twenty-five teeth from each group were subjected to immediate dye leakage assessment under vacuum conditions with methylene blue dye (2%), pH 7. Linear dye penetration was measured following longitudinal splitting. The other 25 teeth from each group were incubated in Ringer's solution for 12 weeks before leakage assessment by the same method. Control teeth were included in each component of the study. Mean linear dye penetration was: amalgam—5.17mm at baseline, 2.33mm after 12 week's incubation; Gallium Alloy GF—2.21mm at baseline, 1.41mm after 12 week's incubation. The apical marginal seal of both materials improved significantly following storage in Ringer's solution (P < 0.001). Gallium Alloy GF provided a better apical seal than amalgam, both at baseline and following storage (P < 0.001). Subjective evaluation of the general handling characteristics of Gallium Alloy GF revealed that it was a more difficult material to manipulate than amalgam, largely because of its wetting ability and consequent adhesion to dental instruments.     

Dentin penetrability evaluation of three different dyes in root-end cavities filled with mineral trioxide aggregate (MTA)

The purpose of this study was to evaluate the penetration of three dyes in MTA root-end fillings. In 30 single-rooted teeth, cavities for retrofilling were prepared with an ultrasound appliance and filled with MTA. The specimens were randomly assigned to three groups (n = 10) and immersed in the following solutions: 2% methylene blue (MET), 50% silver nitrate (NIT) and 0.2% rhodamine B (ROD). Two transversal slices (1 mm) of the retrofilling region were obtained and evaluated using the Image Tool 3.0 software to obtain a quantitative evaluation (in mm2) of the dye penetration around the retrofillings. Data were submitted to statistical analysis using Students t-test. The lowest degree of dye penetration was observed for the NIT group, in both slices (p < 0.05). Dye penetration was significantly larger in the ROD group when compared to the NIT group, in both slices (p < 0.05), and to the MET group, only in slice 1 (p < 0.05). Within the limitations of this study, it was concluded that the choice of dye could influence the penetration evaluation in root-end filling studies, and that the NIT had the lowest penetration capacity in the apical dentine.     

Evaluation of apical sealing of three endodontic sealers

AIM: The apical sealing ability of three different endodontic sealers was evaluated in extracted teeth using dye penetration. METHODOLOGY: The root canals of 99 extracted human maxillary central incisors were prepared sequentially 2 mm beyond the apical foramen with a size 55 Nitiflex file. The teeth were divided into three experimental groups and obturated by lateral condensation of cold gutta-percha and one of the following sealers: group 1, zinc oxide and eugenol sealer (Fill Canal); group 2, glass ionomer sealer (Ketac-Endo) and group 3, epoxy resin sealer (AH Plus). The teeth were covered with nail varnish to within 1 mm of the apical foramen and immersed in 2% methylene blue in a reduced pressure environment for 24 h. After this period, the teeth were washed and cut longitudinally for apical leakage analysis. The values were obtained from the maximum depth of leakage as well as the average between the maximum and minimum values observed for each group. RESULTS: Statistical evaluation of the results showed no significant difference in the leakage between Fill Canal and Ketac-Endo (P > 0.05). Leakage with AH Plus was significantly less (P < 0.01) than with the other sealers. CONCLUSIONS: All three sealers allowed some leakage to occur. Leakage with AH Plus was significantly different than with Fill Canal or Ketac-Endo.     

Comparison of apical leakage in teeth obturated with a polyamide varnish or zinc oxide and eugenol cement using lateral condensation.

The sealing ability of copal varnish has been investigated when used as an adjunct in restorative procedures, retrofilling procedures, and dontic obturation procedures. Barrier, a polyamide-type polymer cavity varnish, has been compared with copal varnishes in restorative dentistry. This investigation compared the apical sealing properties of a zinc oxide and eugenol sealer (Roth) with a polyamide varnish (Barrier). Twenty-four teeth were instrumented and divided into two groups, one obturated with gutta-percha and Roth sealer and one with gutta-percha and Barrier, using submersion in methylene blue dye to demonstrate apical leakage. Roth sealer exhibited less dye penetration than Barrier when used as an endodontic sealant (p < 0.02).     

Comparison of different gutta-percha root filling techniques: Thermafil, Quick-fill, System B, and lateral condensation

OBJECTIVES: In this in vitro study, the core (gutta-percha or gutta-percha and carrier)/sealer ratio and the sealing ability were calculated for 4 different gutta-percha techniques: Thermafil, JS Quick-Fill, System B, and lateral condensation. STUDY DESIGN: One hundred single-rooted teeth were instrumented and obturated. Forty of the teeth were embedded in resin and sectioned horizontally at 1, 2,3, and 4 mm from the anatomic apex. Photographs were taken of each section, and the total area of the canal filled with core material or sealer was calculated. Sixty of the teeth were kept in wet storage for 90 days, after which the teeth were immersed in 2% methylene blue for 48 hours. The length of dye penetration was measured. RESULTS: Roots obturated with Thermafil and JS Quick-Fill contained significantly more core material than did those obturated with System B or with lateral condensation. The lateral condensation technique had the lowest core/sealer ratio (P < .05). Roots using Thermafil and Quick-Fill showed significantly less dye leakage than did the lateral condensation technique. CONCLUSIONS: Through use of these techniques in vitro, Thermafil and JS Quick-Fill with carrier and System B were found to be superior to the lateral condensation technique in terms of core/sealer ratio. Thermafil and Quick-Fill were superior to lateral condensation in terms of dye leakage.     

Use of glass ionomers as retrofilling materials

Many materials have been used as retrofillings. Because of the bonding property of glass ionomer cement, this study was conducted to evaluate its possible use as a retrofilling material. Seventy human maxillary anterior teeth were chosen. The root canal systems were cleansed and shaped, and the teeth were assigned to six groups of 10 each. The root canals were obturated with gutta-percha and Grossman sealer, and the apical 2 mm of each root was resected. In all groups a retrofilling preparation was made to a depth of a number 331 bur. The apical preparations were filled in the following manner: silver amalgam (group I), silver amalgam plus two layers of varnish (group II), Ketac-Silver plus two layers of varnish (group III), Ketac-Silver without varnish (group IV), Ketac-Fil plus two layers of varnish (group V), Ketac-Fil without varnish (group VI), and Ketac-Bond (group VII). All the root surfaces with the exception of 2 mm from the resected line were coated with two layers of clear varnish. All the teeth were immersed in methylene blue for 24 hours. After vertical sectioning, dye penetration was measured under a dissecting microscope. The mean apical leakage (in millimeters) was as follows: I = 0.57, II = 0.39, III = 0.22, IV = 0.54, V = 0.11, VI = 0.46, and VII = 0.17. One-way analysis of variance performed on the group means indicated that Ketac-Fil with varnish (group V) and Ketac-Bond (group VII) had significantly less leakage than other groups (p less than 0.05). This study indicates that Ketac-Fil and Ketac-Bond may have potential as retrofilling materials.     

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 in vitro study of apical and coronal microleakage of laterally condensed gutta percha with Ketac-Endo and AH-26

The purpose of this in vitro study was to compare both apical and coronal dye penetration when Ketac-Endo and AH-26 sealers were user with laterally condensed gutta percha. Crowns were removed from 28 teeth and the root canals were biomechanically prepared. The teeth were divided into two groups of 12 teeth. each and a control group of 4 teeth. Root canals in the two experimental groups were filled with laterally condensed gutta percha and either Ketac-Endo or AH-26 sealer. The ketac-Endo group had the coronal 3 mm of gutta percha and sealer removed and the resultant cavity was filled with Ketc-Endo alone. After the sealers had set, the root surfaces were coated with nail varnish except at the apex and at the coronal end. Positive control had no root fillings and were coated with nail varnish in the same manner while the negative controls were sealed apically and coronally with Cavit prior to apically and coronally with Cavit prior to sealing the entire external root surface with nail varnish. Specimens were placed in 2% methylene blue dye in a vacuum of 660 mm of mercury for five minutes and than left immersed for a further two days. The roots were vertically sectioned to determine the following mean levels of dye penetration: keta-Endo, 1.08 mm apically and 6.29 mm coronally; AH-26, 0.75 mm apically and 6.67 mm coronally. Positive controls had total leakage and negative controlls had no leakage. This study demonstrated that the apical and coronal seals obtained with Ketac-Endo and AH-26 were not significantly different although the apical seal obtained with each material was significantly better than the corresponding coronal seal.     

An in vitro study of apical and coronal microleakage of laterally condensed gutta percha with Ketac-Endo and AH-26

The purpose of this in vitro study was to compare both apical and coronal dye penetration when Ketac-Endo and AH-26 sealers were user with laterally condensed gutta percha. Crowns were removed from 28 teeth and the root canals were biomechanically prepared. The teeth were divided into two groups of 12 teeth. each and a control group of 4 teeth. Root canals in the two experimental groups were filled with laterally condensed gutta percha and either Ketac-Endo or AH-26 sealer. The ketac-Endo group had the coronal 3 mm of gutta percha and sealer removed and the resultant cavity was filled with Ketc-Endo alone. After the sealers had set, the root surfaces were coated with nail varnish except at the apex and at the coronal end. Positive control had no root fillings and were coated with nail varnish in the same manner while the negative controls were sealed apically and coronally with Cavit prior to apically and coronally with Cavit prior to sealing the entire external root surface with nail varnish. Specimens were placed in 2% methylene blue dye in a vacuum of 660 mm of mercury for five minutes and than left immersed for a further two days. The roots were vertically sectioned to determine the following mean levels of dye penetration: keta-Endo, 1.08 mm apically and 6.29 mm coronally; AH-26, 0.75 mm apically and 6.67 mm coronally. Positive controls had total leakage and negative controlls had no leakage. This study demonstrated that the apical and coronal seals obtained with Ketac-Endo and AH-26 were not significantly different although the apical seal obtained with each material was significantly better than the corresponding coronal seal.     

Effect of dentine surface treatment on leakage of root fillings with a glass ionomer sealer

The purpose of this study was to observe the quality of seal of the glass ionomer cement, Ketac-Endo, after treatment of the root canal wall. The root canals of 140 extracted human teeth were prepared biomechanically. The root canals were treated with either EDTA or received an intracanal dressing of calcium hydroxide or camphorated paramonochlorphenol. The root canals were filled by the lateral condensation technique with gutta-percha points and the sealer Ketac-Endo, or zinc oxide-eugenol cement or Sealapex. The teeth were placed into a 2% methylene blue dye solution inside a flask, which was attached to a vacuum pump. Leakage was measured linearly. Sealapex exhibited significantly less leakage than Ketac-Endo or zinc oxide-eugenol cement (P < 0.01). The use of EDTA and intermediary dressings reduced significantly (P <0.01) the leakage observed with the zinc oxide-eugenol sealer and Ketac-Endo.     

Evaluation of the apical seal in root canals prepared with a new rotary system and obturated with a methacrylate based endodontic sealer: an in vitro study

The purpose of this study was to evaluate in vitro the apical seal of root canals prepared with a new rotary system, Anatomic Endodontic Technology (AET) and filled with a methacrylate based endodontic sealer and a single gutta-percha cone and a lateral condensation technique, using the methacrylate based endodontic sealer/filler or Grossman's cement. The root canals of 45 freshly extracted human maxillary anterior teeth were prepared and then randomly assigned to three groups of 15 teeth each. After cleaning and shaping the teeth were obturated as follows: in group 1 the canals were filled with a methacrylate based sealer and a single gutta-percha cone; in group 2 the canals were filled using a lateral condensation technique with gutta-percha and the methacrylate based sealer; and in group 3, the canals were filled by means of lateral condensation of gutta-percha and Grossman's cement (control group). The specimens were stored in 100% relative humidity at 37 degrees C for 72 h, after which the coronal portion and the root surface of each tooth was covered with three layers of nail varnish and a final layer of sticky wax. After immersion in 2% methylene blue dye for 7 days, the specimens were imbedded in clear orthodontic resin and sectioned. Dye penetration was evaluated by an independent investigator using a stereo microscope. The results demonstrated that more pronounced leakage occurred in root canals obturated with the lateral condensation technique and Grossman's cement (p < 0.05). The least amount of dye leakage was observed for group 1 and 2 in which the methacrylate based sealer was used, either with a single gutta-percha cone or with lateral condensation of gutta-percha.     

A comparative study of apical leakage with endodontic implant stabilizers

The apical seals of 75 extracted teeth that were treated with three methods of endodontic implant stabilizers were compared with the seals of 25 teeth filled with silver cones and 25 teeth filled with laterally condensed gutta-percha. Apical leakage was measured with the use of methylene blue dye solution. Statistical analysis showed that there were significant differences between the apical leakage obtained from the teeth treated with endodontic implant stabilizers and those teeth filled with silver cones and with laterally condensed gutta-percha.