In vitro endotoxin penetration of coronally unsealed endodontically treated teeth

Lipopolysaccharide penetration analysis of two different resin cement systems to dentin and ceramic surface

Background/purpose

One of the challenges in adhesive ceramic restorations is deterioration of tooth-cement-ceramic interfaces. This study was to quantitatively investigate lipopolysaccharide (LPS) penetration through adhesive ceramic restorations.

Materials and methods

Standardized holes were formed on ceramic (IPS Empress CAD, Ivoclar Vivadent) and human dentin discs. Prepared discs were randomly assigned to experimental groups (n = 6/group): SC, self-adhesive resin cement (SmartCem 2, Dentsply Sirona) bonded to ceramic discs; ST, self-adhesive resin cement bonded to dentin discs; VC, etch-and-rinse resin cement (Variolink II, Ivoclar Vivadent AG) bonded to ceramic discs; VT, etch-and-rinse resin cement bonded to dentin discs. The specimens underwent thermocycling (10,000 cycles; 5-55 °C) then LPS penetration test until 5-weeks. A mixed effect analysis using R statistical language was performed for data analysis.

Results

Dentin and ceramic bonded with etch-and-rinse resin cements (groups VT and VC) showed significantly less penetration than those with self-adhesive resin cement (groups ST and SC) (P < 0.05). ST showed significantly lower penetration than SC (P < 0.05), that showed similar penetration with positive control (P > 0.05). VC showed minimal penetration during observed time of period (P < 0.05). Scanning electron microscope observations showed different interfacial characteristics among the groups.

Conclusion

Within the limitation of this study, etch-and-rinse resin cement showed less LPS penetration than self-adhesive resin cement on both ceramic and dentin surfaces.

Calcium Silicate-based Sealer Extrusion into the Mandibular Canal: Three Different Recovery Outcomes: A Report of Three Cases

The use of calcium silicate-based sealers (CSS) is increasing in dentistry as result of their favorable properties. The inadvertent extrusion of these sealers into the mandibular canal (MC) can result in temporary or permanent neurosensory alterations. Three different recovery outcomes of CSS extrusion into the MC after endodontic treatment of mandibular molars, confirmed by cone beam computed tomography (CBCT) imaging, are described. In Case 1, CSS from the mesiolingual canal of #31 was extruded into the MC during obturation. The patient reported paresthesia. The symptoms of paresthesia were completely resolved by nine months. In Case 2, CSS from the mesial canals of #30 was extruded into the MC during obturation. "Plasma-like spreading pattern" of the extruded sealer was observed on the radiographs. The patient reported paresthesia and dysesthesia. In addition, the patient complained of hyperalgesia with heat and mechanical allodynia. The symptoms continued to persist during follow up. At 22 months, the patient still reported persistent paresthesia, hyperalgesia and mechanical allodynia, affecting the ability to eat. In Case 3, CSS from the distal canal of #31 was extruded into the MC during obturation. The patient did not report any paresthesia or dysesthesia. All three patients elected a follow up approach and monitoring rather than surgical intervention. These cases illustrate the need for the development of guidelines for the management of iatrogenic CSS extrusion into the MC because such an occurrence may not necessarily result in permanent, temporary or no neurosensory alterations.

Sealing ability in vitro study and biocompatibility in vivo animal study of different bioceramic based sealers

INTRODUCTION

The effectiveness of root canal therapy in endodontic practice is largely determined by providing a compact fluid-tight closure at the apex of the root canal, which inhibits irritant entry and buildup, which leads to a biological breakdown of the attachment mechanism and failure. During obturation, along with gutta-percha, root canal sealers are employed to fill voids and seal root canals. Root canal sealers come in a variety of shapes and sizes, each with its own set.

AIM

Evaluation of sealing ability in vitro study by using scanning electron microscopy (SEM) and biocompatibility in vivo animals study of BioRoot RCS and meta Biomed bio_ceramic sealer (CeraSeal RCS) and compared the findings with that of Zinc oxide eugenol (ZOE) sealer as control.

MATERIALS AND METHODS

This study utilized two bio_ceramic sealers (BioRoot RCS and meta Biomed bio_ceramic sealer (CeraSeal RCS) and compared the findings with that of ZOE sealer as control. Biocompatibility was determined by examining histopathological biopsy specimens collected from rabbits. Each rabbit had four dentin tubes implanted into the subcutaneous tissues, one for BioRoot RCS, one for CeraSeal RCS, and one for ZOE RCS, with the fourth tube being empty haematoxylin and eosin were used to stain histological sections, and a light microscope was used to evaluate them. Extracted human single canal premolars were used to evaluate the sealing ability. The root canals were divided into three sections (coronal, middle, and apical). SEM was used to assess the adhesion quality at the sealer-dentin interface.

RESULTS

BioRoot and CeraSeal sealers have excellent sealing adaptation and biocompatibility, as well as rapid tissue recovery, while ZOE sealers have a slower recovery of inflammatory reaction results when compared to bio_root and ceraSeal sealers, as well as a less sealing adaptation than the two other bio_ceramic sealers.

CONCLUSION

In general, the two bioceramic sealers tested were biocompatible and capable of sealing or adhesion. While ZOE had less adherence ability and less biocompatibility.

Effect of phytic acid as an endodontic chelator on resin adhesion to sodium hypochlorite-treated dentin

Objectives

Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed.

Materials and Methods

Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded.

Results

The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA.

Conclusions

IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.

Evaluation of the sealing ability of different root canal sealers: a combined SEM and micro-CT study

Objective

The purpose of this study was to analyze the ability of multiple compounds to seal the dental tubules using scanning electron microscopy (SEM) and micro-computed tomogra-phy (micro-CT).

Material and Methods

Twenty-four single-root human mandibular premolars were selected and instrumented with nickel-titanium rotary file and the final file size was #40/06. They were then randomly allocated into 2 groups, and all samples were filled with single cone gutta-percha (#40/06) and one of the tested sealers (AH Plus and EndoSequence BC sealers). All specimens were scanned using micro-CT and then three from each group were randomly selected for SEM analysis.

Results

According to SEM, both root canal sealers showed sufficient adaptation to dentin along the whole length of the root canal, though the coronal sections presented superior sealing than the apical sections. Micro porosity analyses revealed that the volume of closed pores and the surface of closed pores had the largest values in the coronal sections, followed by the middle and the apical sections for both sealants (p<0.05). However, no significant difference was observed for those two parameters between AH Plus and EndoSequence BC sealers in any of the three sections (p>0.05), whereas they were larger in the apical section when the AH Plus sealer was used.

Conclusions

By using the single cone technique, neither EndoSequence or AH Plus pro-vides a porosity-free root canal filling. The EndoSequence BC sealer may have similar sealing abilities regarding the whole root canal as the AH Plus sealer. A better sealing effect could be obtained in the coronal and middle sections of a root canal than the apical part by using the tested sealers.

Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1), with gutta-percha + Sealapex (G2), and with gutta-percha + AH Plus (G3). Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0), applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively), whereas G1 showed significantly higher values (mean: 105.2 ng mL-1). At 60 days, leakage values were 182.6 ng mL-1 for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

Sealing ability of a novel hydrophilic vs. conventional hydrophobic obturation systems: A bacterial leakage study

Aim:

Comparative assessment of apical sealing ability of a novel Smart-Seal System, Resilon, and conventional Gutta-Percha system using a bacterial leakage model.

Materials and Methods:

Seventy freshly extracted human single rooted teeth with fully formed apices were randomly divided into three groups (20 each) and two control groups (5 positive and 5 negative). Teeth were de-coronated, and roots were standardized to a working length of 16 mm. Root canal preparation was done with rotary pro-taper file system in all groups. Group A was obturated using Smart-Seal system (Hydrophilic), Group B using Resilon/Epiphany system (Hydrophilic), and Group C using Gutta-Percha (GP)/AH plus system (Hydrophobic) in a single cone technique. Using Enterococcus faecalis, a split chamber bacterial leakage model was developed to evaluate the sealing ability of three obturation systems. Samples will be monitored every 24 hours for 60 days.

Results:

All three groups have shown leakage. Novel Smart-Seal System and Resilon have shown similar results and relatively lesser samples leaked in comparison to GP obturations at the end of the observation period. There was no significant difference amongst Resilon and Smart-Seal System (P > 0.05) but there was a significant difference amongst them when compared to GP obturations (P < 0.05).

Conclusion:

Hydrophilic obturations of the root canal shows a better resistance to bacterial leakage as compared to hydrophobic obturations.

Evaluation of bacterial microleakage of root canals irrigated with different irrigation solutions and KTP laser system

OBJECTIVE

The aim of this study was to evaluate bacterial microleakage of the root canals irrigated with different irrigation solutions and the potassium-titanyl-phosphate (KTP) laser system and filled with gutta-percha and AH26 root canal sealer. In addition, the effect of the irrigation solutions on dentin surface was evaluated with a scanning electron microscope (SEM).

BACKGROUND DATA

A few studies have reported that KTP laser has the capacity to remove the smear layer. Many researchers have demonstrated that propolis has a bactericidal effect. Both are important effects on root canal treatments.

MATERIALS AND METHODS

One hundred and twenty single-root single-canal mandibular premolar teeth were used for this study. The root canals were prepared by Dentaport Root ZX and ProTaper rotary instruments with the crown-down technique. The specimens were randomly divided into five groups of 20 teeth each. Each group was irrigated with 17% ethylenediaminetetraacetic acid (EDTA), 20% propolis, 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate (CHX), and KTP laser, respectively. A total of 20 teeth were used as controls-10 positive controls and 10 negative controls-which were irrigated with distilled water. The root canals were filled with gutta-percha and AH-26. The external surfaces of specimens were covered with three layers of nail varnish except the apical third. The teeth were inserted into Eppendorf plastic tubes and suspended in glass bottles containing sterile broth. All specimens were inoculated every 5 days with Enterococcus faecalis. The contamination onset time was continuously recorded, as turbidity was the first indication of contamination in a period of 30 days.

RESULTS

All statistical analysis was performed using the SPSS for Windows version 15.0 software. A χ(2) test was computed and the statistical significance was set at p<0.05. The controls behaved as expected.

CONCLUSIONS

This study showed that different irrigation solutions and KTP laser allowed microleakage of E. faecalis.

Dynamic sealing ability of MTA root canal sealer

AIMS

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

The effect of root canal sealers and timing of cementation on the microlekage of the parapost luted with resin cement

OBJECTIVES

The objectives of the study were to study the effect of root canal sealers either eugenol or non-eugenol and timing of cementation on microleakage of the parapost luted with resin cement.

MATERIALS AND METHODS

Seventy extracted human, single-rooted teeth were instrumented using a crown-down technique. All teeth were instrumented up to a size 50 .04 taper ProFile followed by the use of Gates Glidden drills from size 2 up to 5. Following instrumentation, the teeth were randomly divided into four experimental groups of fifteen teeth each, based on type of root canal sealer (eugenol or non-eugenol sealer) and timing of post cementation (immediate or delayed). The remaining ten teeth were divided into two control groups with five teeth per group. All teeth were tested for microleakage using a fluid filtration method.

RESULTS

The microleakage of the paraposts luted with resin cement increased over time, irrespective of sealer type or timing of post cementation. Immediate post cementation following obturation with AH26 (non-eugenol sealer) produced the least microleakage at all three time periods at 24 h, 2 months and 3 months.

CONCLUSIONS

The microleakage paraposts luted with resin cement was not influenced by either sealer type or timing of post placement. All experimental groups demonstrated a significant increase in microleakage over time as well as the presence of voids at the resin-dentin interface.

In vivo evaluation of the sealing ability of two endodontic sealers in root canals exposed to the oral environment for 45 and 90 days

This in vivo study evaluated the sealing ability of a resin-based sealer (AH Plus) and a zinc oxide-eugenol sealer (Endofill) in dogs' teeth, exposed to the oral environment for 45 and 90 days. Forty eight lower incisors from 8 dogs were endodonticaly treated. A stratified randomization determined the sealer use in each root canal. All canals were filled using the lateral condensation technique. The excess filling material at the cervical portion of the root canal was sectioned, leaving a 10-mm obturation length inside the canal. Teeth were provisionally sealed with glass ionomer cement for 24 h and the canals were exposed to the oral environment for either 45 or 90 days. Therefore, the experimental groups were as follows: A45- AH Plus for 45 days; A90- AH Plus for 90 days; E45- Endofill for 45 days; and E90- Endofill for 90 days (n=12). After the experimental period, the dogs were killed and the lower jaw was removed. The incisors were extracted and the roots were covered with two coats of nail varnish. The teeth were immersed in India ink for 96 h and submitted to diaphanization. Dye leakage (in mm) was measured using stereomicroscopy (10x magnification). The results were statistically analyzed using two-way ANOVA and Tukey test for multiple comparisons (á = 0.05). Group E90 (2.03+/-0.94) showed significantly higher mean leakage value than all other groups (p<0.001). None of the sealers, in both study conditions, were able to prevent dye leakage.

Comparative in vivo analysis of the sealing ability of three endodontic sealers in dog teeth after post-space preparation

This study compared the sealing ability of RoekoSeal, AH Plus and EndoRez in dog premolars after post-space preparation and exposure to the oral environment. Seventy-four root canals were cleaned, shaped and filled with gutta-percha and one of the sealers. Post spaces were prepared with about 4-mm root canal filling remaining in the apex. Teeth were sealed for 24 h for sealer setting. Teeth were exposed to the oral environment for 45 days. The dogs were killed and root canals were soaked in India ink and sealed for 96 h. The teeth were cleared, and leakage was measured under stereoscopy. The Kruskal-Wallis test was used for analysis. A significant difference was found between EndoRez and RoekoSeal groups (P < 0.05). EndoRez had lower leakage values than RoekoSeal after 45-day exposure to the oral environment. No statistic difference was found in the comparison of AH Plus with the other sealers under study.

Microbial Leakage of Gutta-percha and Resilon™ Root Canal Filling Material: A Comparative Study Using a new Homogeneous Assay for Sequence Detection

The sealing ability of gutta-percha/sealer root canal filling was compared to a new thermoplastic synthetic polymer-based obturation material (Resilon TM), using a microleakage model and a new sequence detection assay One Cut Event AmplificatioN (OCEANTM). Eighty-eight extracted human teeth, shaped with K-Files and the ProTaper Technique, were randomly assigned to four groups (n = 22) and obturated in the apical 5 mm. Group R were obturated with the Resilon/Epiphany technique; group GP were obturated with gutta-percha and Zinc oxide eugenoe sealer; group RCH and GPCH received calcium hydroxide intracanal medication before being obturated. Sterilized specimens were inoculated with Enterococcus faecalis and incubated in sterile medium for 47 days. DNA extracted from the specimens was amplified by PCR and then identified by the OCEAN technique. Samples obturated with Resilon root canal filling material showed a greater number of microleakage events than the other groups (p = 0.036). Calcium hydroxide medication did not have a relevant impact on the quality of the apical seal (p = 0.044).

Endotoxin contamination in the dental surgery

Dental waterlines contain large numbers of Gram-negative bacteria. Endotoxin, a component of such organisms, has significant health implications. Paired samples of dental unit water and the aerosols generated during dental procedures were collected, and assayed for bacteria and endotoxin levels, using heterotrophic plate counts and the Limulus amoebocyte lysate test. Consistent with published studies, the extent of bacterial contamination in the dental waters sampled for this investigation surpassed the levels associated with potable water, with counts in excess of 2.0x10(6) c.f.u. ml(-1) in some samples. Correspondingly high concentrations of endotoxin [up to 15 000 endotoxin units (EU) ml(-1)] were present in the water. A statistically significant Spearman correlation coefficient of rho=0.94 between endotoxin (EU ml(-1)) and bacterial load (c.f.u. ml(-1)) was demonstrated. All of the aerosol samples contained detectable endotoxin. Further studies of the consequences of dental endotoxin exposure, and evaluation of means to prevent exposure, are warranted.

Bacterial penetration along different root canal filling materials in the presence or absence of smear layer

AIM

To study the effect of the smear layer on the penetration of bacteria along different root canal filling materials and to examine the dentine/sealer and sealer/core material interfaces for the presence of bacteria.

METHODOLOGY

A total of 110 human root segments were instrumented to size 80 under irrigation with 1% sodium hypochlorite. Half of the roots were irrigated with a 5-mL rinse of 17% EDTA. Roots with and without smear layer were filled with gutta-percha (GP) and AH Plus sealer (AH), GP and Apexit sealer (AP), or RealSeal cones and sealer (RS). Following storage in humid conditions at 37 degrees C for 7 days, the specimens were mounted into a bacterial leakage test model for 135 days. Survival analyses were performed to calculate the median time of leakage and log-rank test was used for pairwise comparisons of groups. The level of significance was set at P = 0.05. Selected specimens were longitudinally sectioned and inspected by scanning electron microscopy for the presence of bacteria at the interfaces.

RESULTS

In the presence of the smear layer, RS and AP leaked significantly more slowly than in its absence. In the absence of the smear layer, AH leaked significantly more slowly than RS. SEM results indicated a differential pattern of bacterial penetration among the sealers.

CONCLUSIONS

Removal of the smear layer did not impair bacterial penetration along root canal fillings. A comparison of the sealers revealed no difference except that AH performed better than RS in the absence of the smear layer.

Microbial leakage and apical inflammatory response in dog's teeth after root canal filling with different sealers, post space preparation and exposure to the oral environment

Coronal leakage is an important factor affecting the outcome of endodontic therapy. This study evaluated the microbial leakage (ML) and the apical inflammatory response (AIR) in dog’s teeth after root canal filling with three endodontic sealers, post preparation and exposure to the oral environment, testing the hypothesis that there is a positive correlation between these two histological parameters (ML and AIR). Sixty-four root canals of 8 mongrel dogs were cleaned, shaped and randomly distributed into groups according to the sealer to be used: Sealer 26 (n=18); AH Plus (n=18); RoekoSeal (n=19); no sealer – control group (n=9). Root canals were filled by the lateral condensation technique. Post space preparation left 4 mm of filling material in the apical root third, and specimens were exposed to the oral environment for 90 days. The dogs were killed and jaw blocks were histologically processed using Brown & Brenn and HE staining techniques. ML and AIR were scored from 1 to 4. Results were analyzed statistically using ANOVA, Duncan’s post-hoc test and Spearman’s correlation. ML and AIR score means were: Sealer 26 - 2.44±0.98 and 2.50±0.70; AH Plus - 2.50±0.78 and 2.22±0.54; RoekoSeal - 1.84±0.95 and 2.63±0.83; Control - 2.56±1.23 and 3.11±0.60. Statistically significant differences in AIR scores were found between the AH Plus and control groups (p<0.05). Although RoekoSeal had the lowest ML means, and AH Plus, the lowest AIR means after 90-day exposure to the oral environment, no statistically significant differences were found between the three sealers under study, and no correlation was found between ML and AIR.

Sealer area associated with cold lateral condensation of gutta-percha and warm coated carrier filling systems in canals prepared with various rotary NiTi systems

AIM

To compare the area of sealer surrounding root fillings completed by two coated carrier systems (Thermafil Obturator and System GT Obturator) and the cold lateral compaction technique, following root canal preparation with two different NiTi rotary systems (Profile ISO and System GT).

METHODOLOGY

Sixty extracted human mandibular premolars were instrumented with ProFile ISO 0.06 taper and System GT instruments (n = 30 each). The teeth were divided into four subgroups (n = 15) for filling as following: group 1: ProFile + Thermafil Obturator, group 2: ProFile + Cold Lateral Compaction, group 3: System GT + GT Obturator, and group 4: System GT + Cold Lateral Compaction. In all groups the canals were prepared to a final size of 40, 0.06 taper in accordance with the manufacturer's instructions and Topseal was used as a sealer. Horizontal sections were obtained every 1 mm up to 12 mm from the apical foramen. Sections were digitally photographed under a stereomicroscope and the images were transferred to an IBM-compatible PC for image analysis. The cross-sectional area of the root canal and the area filled by sealer were calculated for each section and compared statistically both at all levels and by grouping the data as apical, middle and coronal segments; using the Kruskal-Wallis test with Bonferroni correction and chi-square tests (P = 0.05).

RESULTS

In the apical third (1-4 mm), the GT Obturator (group 3) had significantly less area of sealer (P < 0.05), while the difference between groups 1 and 2 was not significant (P > 0.05). For the middle and coronal thirds, both coated-carrier systems had significantly less area of sealer compared with their laterally compacted counterparts (P < 0.05).

CONCLUSIONS

With the combined use of ProFile + Thermafil Obturator and System GT + GT Obturator, significantly less area of sealer occurred than that achieved with both NiTi preparation systems followed by cold lateral compaction.

Effects of different root canal obturation techniques on bacterial penetration

OBJECTIVES

The aim of this study was to compare bacterial penetration following obturation with 5 different techniques.

STUDY DESIGN

This study was performed on 120 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 100). One hundred teeth were randomly divided into 5 groups of 20 teeth each and obturated with System B (Sb), Lateral Compaction (Lc), Thermafil (T), Single ProTaper Gutta-percha (P), and laterally compacted ProTaper Gutta-percha (PLc). Enterococcus faecalis was used for determination of the bacterial penetration. Evaluation was carried out for 60 days.

RESULTS

At 30 days, the chi2 test showed that the slowest penetration was observed in Group Sb and Group PLc, which were not significantly different from each other. The fastest penetration in the all experimental groups was observed in Group T and Group P, which were not significantly different from one another. Also, there was no statistically significance difference (P > .05) among all groups at 60 days.

CONCLUSION

It may be concluded that under the conditions of this study System B and laterally compacted ProTaper Gutta-percha prevent bacterial penetration of the root canal at 30 days. Furthermore, there was no difference among obturation techniques at 60 days.

Bacterial penetration after obturation with four different root canal sealers

The aim of this study was to compare bacterial penetration after obturation with lateral compaction technique using four different root canal sealers. This study was performed on 100 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 80). 80 teeth were randomly divided into five groups of 20 teeth each and obturated with AH 26 (A), AH Plus (AP), Sealapex (S), Ketac-Endo (K) root canal sealers. Evaluation was carried out for 60 days. After 30 days of comparing the bacterial penetration values, total penetration was observed in 85% of the Group AP, and group K, 80% of the group S, and 75% of the group A. According to the results of chi(2) test, there was no statistically significant difference observed between any groups (p > 0.05). After 60 days of comparing the bacterial penetration values, total penetration was observed in 100% of the group AP, group K, and group S and 95% of the group A. It may be concluded that under the conditions of this study, there was no difference in the bacterial penetration of the four root canal sealers tested at 30 and 60 days.

The relation between apical periodontitis and root-filled teeth in patients with periodontal treatment need

AIM

To investigate a number of clinical and treatment variables that might have influenced the prevalence of apical periodontitis in root-filled teeth in a population of periodontally compromised patients.

METHODOLOGY

This investigation was a retrospective cross-sectional study on data collected from periodontal charts in addition to intra-oral full-mouth radiographs from patients attending the Department of Periodontology of the Dental School of the Ghent University Hospital. Periodontal parameters (clinical attachment loss and the lowest marginal bone level, the history of periodontal treatment), endodontic treatment (length, homogeneity and overall quality of the root filling) and the quality of coronal restorations were related to the prevalence of apical periodontitis. A total of 272 root-filled teeth in 94 patients were evaluated.

RESULTS

The periapical condition was significantly influenced by the quality of the root filling and the coronal filling (P < 0.05). More apical periodontitis was seen when the coronal level of the root filling exceeded the marginal bone level (P < 0.005). The marginal periodontal condition seemed to influence the periapical status. Teeth with apical periodontitis were associated with significantly more extended marginal bone loss (P < 0.001). Significantly less apical periodontitis was seen in patients that had received marginal periodontal treatment (P < 0.005), compared with untreated periodontal patients.

CONCLUSIONS

Signs of periodontal disease, as reflected by marginal bone loss, are of importance for the periapical condition of root-filled teeth. Efforts should be taken in preventing spread of infection through the periodontal-endodontic pathway by periodontal infection control and a high quality of root filling and coronal filling. Care should also be taken to seal the coronal cavity up to the level of the root filling, where it is advisable to reduce the coronal level of the root filling below or at least at the level of the surrounding marginal bone.

An in vitro study of coronal leakage after intraradicular preparation of cast-dowel space

STATEMENT OF PROBLEM

Coronal leakage can produce contamination of periapical tissues, resulting in endodontic failure.

PURPOSE

The purpose of this in vitro study was to evaluate the ability of 2 sealers to prevent coronal leakage in canals filled with gutta-percha and prepared for cast dowels but without coronal sealing.

MATERIAL AND METHODS

The crowns of 60 extracted single-rooted teeth were amputated. The root canals were prepared corono-apically and filled with gutta-percha cones and 1 of 2 different endodontic sealers: a resin-based sealer (AH Plus) and a calcium hydroxide-based sealer (Sealapex). Specimens were then stored in water for 7 days to allow the sealers to set. The specimens were prepared in 1 of 2 ways: no preparation for cast dowel or preparation of cast-dowel space (n=15). External surfaces of the roots were sealed with cyanoacrylate cement. The teeth were thermal cycled at 5 degrees and 55 degrees C in water baths (dwell time=30 seconds) for 500 cycles. Specimens were then submerged in 2% methylene blue colorant for 24 hours. Microleakage was measured according to the percentage of area stained with the colorant. Effects of each factor (cast-dowel preparation and type of sealant) on microleakage were analyzed by the Student t test (alpha=.05).

RESULTS

The AH Plus and Sealapex sealers with cast-dowel preparation resulted in significantly (P<.001) more leakage compared to sealers with no dowel preparation.

CONCLUSION

Cast dowel-space preparation had a negative influence on the sealing ability of the remnant root-canal filling material.

Effect of root canal filling/sealer systems on apical endotoxin penetration: a coronal leakage evaluation

Endotoxin, elaborated by gram-negative organisms, is an important factor in apical periodontitis. The objective of this study was to evaluate the magnitude of endotoxin penetration through root canal treated teeth using a dual chamber model system. Forty-four maxillary anterior teeth were prepared endodontically and canals filled either by lateral condensation or a warm thermoplasticized technique in combination with either Roth's 801 or AH 26 sealer. Teeth were suspended in the model system with a mixed anaerobic bacterial suspension in the upper chamber and HBSS in the lower chamber. The QCL-1000 LAL assay was used to measure endotoxin at 0, 1, 7, 14, and 21 days. Response feature analysis using trapezoidal area under the curve was performed; the four treatment groups were compared using nonparametric methods. Groups differed (p = 0.028), with thermoplasticized root canal filling/Roth's 801 sealer permitting the least apical endotoxin penetration. Results suggest that Roth's 801 sealer may have a role in inhibiting endotoxin penetration.

Tooth preparation for post-retained restorations

Failure of root canal treatment and/or post crowns can be avoided in many cases if appropriate tooth preparation is carried out. This paper discusses the rationale for the timing of post placement following root canal treatment and appropriate methods for removal of gutta-percha prior to post space preparation. The basic principles of post space preparation are described, which should reduce the risk of weakening the root unnecessarily, causing damage to the periodontium and post perforation.

Diffusion ability of endotoxin through dentinal tubules

The aim of this study was to evaluate the ability of endotoxin to diffuse through dentinal tubules towards the cement and to observe the period of time needed for it to reach the external root surface. Thirty single-rooted human teeth had their crowns and apices removed in order to standardize the root length to 15 mm. Teeth were instrumented until #30 K-file and made externally impermeable with epoxy adhesive, leaving 10 mm of the exposed root (middle third). The specimens were placed in plastic vials and irradiated (60Co gamma-rays). Then, they were divided into 2 groups (n = 15): G1) Escherichia coli endotoxin was inoculated into the root canal of the specimens and 1 ml of pyrogen-free water was put in the tubes; G2) (control): pyrogen-free water was inoculated into the root canals and 1 ml of pyrogen-free water was put in each tube. After 30 min, 2 h, 6 h, 12 h, 24 h, 48 h, 72 h and 7 days, the water of the tubes was removed and replaced. The removed aliquot was tested for the presence of endotoxin. Considering that the endotoxin is a B-lymphocyte polyclonal activator, at each experimental period, B-lymphocyte culture was stimulated with a sample of water removed from each tube and antibody (IgM) production was detected by ELISA technique. The results of IgM production were higher in groups of 24 h, 48 h, 72 h and 7 days in relation to the other studied groups, with statistically significant differences (ANOVA and Tukey's test p < 0.05). Endotoxin was able to diffuse through the dentinal tubules towards the cement, reaching the external root surface after the period of 24 h.

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.

In vitro microbial leakage of endodontically treated teeth using new and standard obturation techniques

Coronal microbial leakage is an important cause of apical periodontitis and thus should be prevented if possible. The purpose of this study was to compare microbial leakage of new and standard obturation techniques over a 30-day period. A split chamber microbial leakage model was used in which Streptococcus mutans placed in the upper chamber could reach the lower chamber only through the obturated canal. Leakage was assessed every day for 30 days. One hundred forty single-rooted human teeth were used in this study, equally split between lateral, vertical, and Obtura II condensation; SimpliFill with Obtura II condensation; FibreFill; and a combination of FibreFill and SimpliFill. Cochran-Mantel-Haenszel row mean score statistics showed a high statistical significance when all groups were compared (p < 0.0001). Microbial leakage occurred more quickly in lateral and vertical condensation techniques compared with SimpliFill and FibreFill techniques. A combination of an apical plug of gutta-percha with SimpliFill and a FibreFill coronal seal was the best obturation technique used (SimpliFill-FibreFill group).

An Evaluation of Microbial Leakage in Roots Filled with a Thermoplastic Synthetic Polymer-Based Root Canal Filling Material (Resilon)

The purpose of this study was to compare bacterial leakage using Streptococcus mutans and Enterococcus faecalis through gutta-percha and a thermoplastic synthetic polymer-based root filling (Resilon) using two filling techniques during a 30-day period. Teeth were decoronated, roots prepared to a length of 16 mm, and instrumented to ISO sizes 40 to 50. A total of 156 roots were randomly divided into 8 groups of 15 roots (groups 1-8) and 3 control groups (12 roots each). Roots were filled using lateral and vertical condensation techniques with gutta-percha and AH 26 sealer (groups 1 and 2) or with gutta-percha and Epiphany sealer (groups 3 and 4). Groups 5 and 6 were filled with Resilon and Epiphany sealer using the lateral or vertical condensation techniques. A split chamber microbial leakage model was used in which S. mutans placed in the upper chamber could reach the lower chamber only through the filled canal. Groups 7 and 8 were identical to groups 5 and 6 respectively; however, E. faecalis was used to test the leakage. Positive controls were filled with Resilon (12 roots) and gutta-percha (12 roots) without sealer and tested with bacteria, whereas negative controls (12 roots) were sealed with wax to test the seal between chambers. All but one positive control leaked within 24 h, whereas none of the negative controls leaked. Resilon showed minimal leakage (group 8: one leakage; groups 5-7: each with two leakages), which was significantly less than gutta-percha, in which approximately 80% of specimens with either technique or sealer leaked. Kruskal-Wallis test showed statistical significance when all groups were compared (p < 0.05). Mann-Whitney U test compared the respective groups and found Resilon groups superior to gutta-percha groups (p < 0.05).

Comparative in vivo analysis of the sealing ability of three endodontic sealers in post-prepared root canals

AIM

To compare the sealing ability of the endodontic sealers AH Plus, Sealer 26 and Endofill in premolar teeth of dogs exposed to the oral cavity after post-preparation.

METHODOLOGY

Forty teeth with two canals each underwent root canal cleaning and shaping. Before filling, the canals were randomly distributed into three groups according to the sealer to be used: Group 1 - AH Plus; Group 2 - Sealer 26; and Group 3 - Endofill (Dentsply, Indústria e Comércio Ltda.). Immediately after filling, the gutta percha and sealer were partially removed from the canals, leaving material only in the apical third of the root. The teeth were temporarily sealed with glass ionomer sealer for 72 h to ensure setting. The coronal seal was then removed and the canals were exposed to the oral cavity for 45 days. The animals were euthanased and their mandibles and maxillae were removed. After abundant irrigation with distilled water, the canals were dried and filled with India ink. The teeth were sealed again for 96 h before extraction. The roots of the extracted premolars were separated and stored in labelled test tubes. The roots were cleared and the extent of dye penetration was measured with a 20x stereoscopic magnifying lens.

RESULTS

Statistical analysis revealed that there were significant differences between the sealers studied (P < 0.001). Means for the extent of dye penetration for AH Plus, Endofill and Sealer 26 were, respectively, 0.13, 2.27 and 3.08 mm.

CONCLUSIONS

After 45 days exposure to the oral cavity, none of the sealers was capable of preventing leakage and coronal dye penetration. There were significant differences between the sealers studied, in terms of mean dye penetration.

Bacterial status in root-filled teeth exposed to the oral environment by loss of restoration and fracture or caries - a histobacteriological study of treated cases

AIM

To describe histological and microbiological findings in teeth where root fillings had been exposed to caries and the oral environment for a prolonged period.

METHODOLOGY

For inclusion in the study, only teeth with a follow-up period of 3 years or more and those that had been without proper restoration for at least a period of 3 months were considered. Some root fillings had been without restoration for several years. In all, 39 roots representing 32 teeth were examined by histology.

RESULTS

The majority of the specimens were without a discernible periapical bone lesion as assessed by radiography. Osteolytic lesions were seen with five roots. Longitudinal tissue sections stained with a modified Brown/Brenn staining technique revealed presence of stainable bacteria in abundance at the canal entrance and in dentinal tubules but were absent mid-root and apically in all but two specimens. Soft tissue attached to the root tip and in apical ramifications displayed distinct inflammatory cell infiltrates, suggesting microbial exposure in 7 of the 39 roots examined. In all other specimens, inflammatory cell infiltrates were either nonexistent or sparse and then associated with extruded sealer material.

CONCLUSIONS

Well-prepared and filled root canals resist bacterial penetration even upon frank and long-standing oral exposure by caries, fracture or loss of restoration.

The comparative sealing ability of hydroxyapatite cement, mineral trioxide aggregate, and super ethoxybenzoic acid as root-end filling materials

A comparison was made of the ability of hydroxyapatite cement, mineral trioxide aggregate, and super ethoxybenzoic acid to prevent the leakage of bacteria from root canals, when used as root-end filling materials. The materials were tested in a double-chamber device in which a root segment connects the upper (delivery) chamber and the lower (receiving) chamber. The root segment was prepared by having the root canal instrumented to a #45 file, and a 3-mm-deep, root-end preparation placed at the apical foramen. The canal of each root segment was filled with gutta-percha, and the root-end preparation was filled with one of three test materials, mixed according to the manufacturer's directions. Negative controls were constructed with sticky wax sealing the apical foramen. A titered suspension of radioactively (3H-thymidine)-labeled bacteria (Enterococcus fecalis) was placed into the delivery chamber, and sterile saline was placed into the receiving chamber such that the apical third of each root section was immersed. At various time points, samples were taken from the receiving chamber, and measured for 3H activity. The results indicated that (a) all the test materials leaked significantly compared with the negative controls; and (b) there was no significant difference found between the leakage rates of the three materials tested.

Periapical health related to the quality of coronal restorations and root fillings

AIMS

To evaluate the impact of the quality of coronal restorations scored on a clinical and radiographic basis and the quality of root fillings on periapical health.

METHODOLOGY

Periapical radiographs were taken of 745 root-filled teeth, randomly selected from patients attending the Ghent University Dental School. The teeth had not received restorative treatment in the previous year. The coronal status was scored both clinically according to modified Ryge's criteria, and radiographically by evaluating the presence of signs of marginal leakage or decay. The quality of the root filling was scored according to criteria of length and homogeneity and the periapical status was categorized on the basis of presence or absence of radiographic signs of apical periodontitis. The relationship between coronal status, quality of root filling and periapical health was determined. The data were analyzed using Chi2 test, Odds ratio, Spearman's r(S) and logistic regression.

RESULTS

Thirty-three percent of the teeth had apical periodontitis as diagnosed radiographically. Teeth with good and poor coronal restorations scored clinically had apical periodontitis in 31.1 and 36.8%, respectively; this difference was not statistically significant. The quality of the coronal restorations scored radiographically had a statistically significant influence on the periapical condition (P<0.001) with apical periodontitis in 23.8 and 49.1%, respectively, for acceptable and unacceptable restorations. Marginal decay did not influence the periapical status. Teeth restored without a base under the coronal filling had apical periodontitis in 41.3%, whereas teeth with a base had significantly less (P<0.005) apical periodontitis (25.9%). Composite-restored teeth exhibited apical periodontitis in 40.5% of cases whilst amalgam-restored teeth had apical periodontitis in 28.4% of cases; this difference was statistically significant (P<0.01). Root-canal posts had no influence on periapical health. The length and homogeneity of the root-canal fillings had a significant influence (P<0.01 and P<0.001, respectively) on the presence of apical periodontitis, as well as the quality of the coronal restoration scored radiographically (P<0.001).

CONCLUSION

The importance of a good coronal restoration, as well as of a good root filling should be emphasized as the technical quality of both influencing the periapical status.

Endodontic failure caused by inadequate restorative procedures: review and treatment recommendations

A review of the literature was performed to determine whether prompt placement of coronal restorations, including sealing and placement of posts and cores, can positively influence the long-term prognosis of teeth after root canal therapy. Both hand and MEDLINE searches were employed to identify peer-reviewed articles on radicular apical integrity after coronal restorations, especially where root canal space was used for post and core fabrication. A total of 41 articles published between 1969 and 1999 (the majority from the 1990s) were reviewed. The literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimizing the leakage of oral fluids and bacteria into the periradicular areas as soon as possible after the completion of root canal therapy.

Evaluation of leakage of bacteria and endotoxins in teeth treated endodontically by two different techniques

Root canal recontamination occurs after contact between oral-bacterial flora and the coronal extremity of the root canal. The aim of this study was to evaluate the time required for endotoxins and bacteria to penetrate through root-canal obturations performed with vertical and lateral gutta-percha condensation techniques. Specimens prepared by the two alternative methods were exposed to contaminated saliva, and leakage into the root was evaluated over time. None of the obturated roots was infiltrated by endotoxins after 31 days. On the contrary, between day 13 and day 37 bacteria had infiltrated all specimens.

Leakage evaluation of root end filling materials using endotoxin

Mineral trioxide aggregate (MTA) has been shown to possess excellent sealing ability when tested with dye, bacteria, and a fluid filtration technique. Endotoxin, a component of the cell wall of Gram-negative bacteria, has been proposed to play a role in the pathogenesis of periradicular lesions. This study used a modified Limulus Amebocyte Lysate test for the presence of endotoxin as a tracer and compared the sealing ability of Super-EBA, IRM, amalgam, and MTA. The results showed that MTA permitted less endotoxin leakage than IRM and amalgam at 1, 2, 6, and 12 wk (p < 0.05), and leaked less than Super-EBA at 2 and 12 wk (p < 0.05).

Comparison of laterally condensed .06 and .02 tapered Gutta-Percha and sealer in vitro

The purpose of this in vitro study was to compare the quality of the seal in canals prepared in a standardized manner and obturated with a .06 or a .02 tapered gutta-percha master cone using lateral condensation. Forty-four extracted human anterior teeth with single, straight canals were divided into two experimental groups of 20 teeth each and two control groups of 2 teeth each. The teeth were instrumented with Series 29 Profile .06 tapered rotary nickel-titanium files to a master apical file of 0.46 mm. Teeth in group 1 were obturated with a .02 tapered master gutta-percha cone and Roth 801 sealer using lateral condensation. Teeth in group 2 were obturated similarly, except a .06 tapered master gutta-percha cone was used. The depth of spreader penetration was recorded in millimeters. Positive control teeth were instrumented but not filled. Negative control teeth were instrumented, obturated, and externally sealed. The teeth were placed into a coronal leakage apparatus that contained an upper and lower reservoir of trypticase soy broth separated by the tooth. A 24-h growth of Proteus vulgaris in 0.25 ml of trypticase soy broth was placed in the coronal reservoir every 7 days for 70 days and incubated at 37 degrees C. Student's t test was used to determine whether there was a difference in spreader penetration between the groups, and a Fisher's exact test was used to determine whether there was a difference in bacterial leakage. The positive and negative controls validated the testing model. When a .02 tapered master cone was used, the spreader penetrated significantly closer to working length than when a .06 tapered master cone was used (p < 0.05). The difference between the groups in the number of samples that demonstrated complete bacterial penetration was not significant (p > 0.05).

Coronal leakage following three obturation techniques

AIM

To compare coronal bacterial and India ink leakage in three different obturation techniques with the smear layer having been removed.

METHODOLOGY

Seventy extracted single-rooted teeth were instrumented to an apical preparation size 7 Profile Series 29 (Tulsa Dental Products, Tulsa, OK, USA). The smear layer was removed and 20 teeth were randomly obturated with lateral compaction, 20 teeth with vertical compaction, and 20 teeth with Thermafil (Tulsa Dental Products, Tulsa OK, USA). Ten teeth were used for positive (five teeth) and negative (five teeth) controls. Teeth were stored for 90 days in 100% humidity, then subjected coronally to Proteus vulgaris for 21 days to assess bacterial leakage. Following bacterial challenge, India ink was placed coronally for a further 21 days, then scored according to depth of dye leakage.

RESULTS

Vertical compaction leaked significantly less than lateral compaction during bacterial challenge. However, when dye was used there were no significant differences.

CONCLUSIONS

Bacterial leakage and dye leakage demonstrated considerable variability. The use of a dye following bacterial testing may highlight the failure of experimental devices and vertical root fractures, thus avoiding false positive results found with bacterial testing alone.

Apical sealing ability of five endodontic sealers

Because apical leakage may be a cause of failure of endodontic treatment, the purpose of this study was to compare the apical seal provided by five endodontic sealers. After cleaning and shaping procedures, the root canals of 75 human cuspids were obturated by lateral condensation using gutta-percha and the following sealers: Kerr Pulp Canal Sealer EWT, Grossman's sealer, ThermaSeal, Sealer 26, and AH Plus. These root-filled teeth were then maintained at 37 degrees C and 100% humidity for two days. After immersion in a solution containing black India ink and fetal bovine serum for five days, the teeth were demineralised and rendered transparent. The extent of dye penetration was examined under a stereomicroscope. The results showed that Grossman's sealer exhibited significantly more leakage than the other sealers, except ThermaSeal. There was no significant difference between ThermaSeal and AH Plus. No significant differences were observed for Kerr Pulp Canal Sealer EWT when compared with either ThermaSeal or AH Plus. There was significantly less leakage for Sealer 26 when compared with the other sealers tested, except AH Plus.

Improving the seal of amalgam cores with cemented dowels: a comparative in vitro radioactive tracer study

Amalgam cores with cemented dowels are commonly used to restore endodontically treated teeth. These restorations were widely studied for their mechanical properties; however, less is known about their sealing ability. The effect of the cement type used for the dowel and that of a bonding agent application were studied in a radioactive tracer coronal leakage study. The sealing ability of posts and cores was also compared with that of 5 mm remaining root canal fillings. Composite luting cement provided a better seal than zinc phosphate cement. The seal provided by 5 mm root canal fillings was poorer than that provided by posts and cores. High variability in seal quality was found among all types of posts and cores studied. This may indicate that the seal provided by cemented dowels with amalgam cores is unpredictable. Because neither the remaining root canal filling nor the post and core may be trusted alone for a seal, each should be performed with the greatest care and both covered with a crown as soon as possible.

Correlation between remaining length of root canal fillings after immediate post space preparation and coronal leakage

The seal provided by root canal fillings after post space preparation was studied using a pressure-driven radioactive tracer assay. The coronal part of root canal fillings was immediately removed, using a hot plugger, to a remaining length of either 3, 5, 7, or 9 mm. Intact root canal fillings of 14 mm served as control. Application of air pressure of 130 mm Hg to the tracer solution drove it through the fillings and into phosphate-buffered saline surrounding the apex. Leakage gradually increased for 28 days, and differences in the leakage through 3 to 9 mm fillings were demonstrated. In a passive system by which an additional group of teeth were tested none of these differences could be detected. It was concluded that: (a) root canal fillings of 3, 5, and 7 mm have an inferior seal, compared with that of an intact filling; (b) the sealing is proportional to the length of the remaining filling; and (c) a passive system is unable to detect these differences, even when conducted for as long as 28 days.

Periapical status of root-filled teeth exposed to the oral environment by loss of restoration or caries

OBJECTIVE

Studies in vitro carried out on extracted teeth have demonstrated that bacterial elements may penetrate root fillings from the coronal to the apical end after a period of exposure to artificial saliva or bacterial culture. To address the clinical significance of this so-called issue of coronal leakage, a retrospective cohort analysis was conducted of 55 patients with root fillings that had been exposed to the oral environment because of caries or absent restorations.

STUDY DESIGN

Cases were matched 1-to-1 with regard to initial pulpal and periapical diagnosis, period after completion of endodontic therapy, tooth type, age of the patient, and the technical quality of the root filling. Only cases with a follow-up period of 3 years or more were included. Radiographs taken at the last follow-up examination were subjected to a masked evaluation.

RESULTS

A total of 14 osteolytic lesions were recorded. In 43 of the 55 matched pairs (78%), there were identical periapical conditions. In 9 pairs, a periapical lesion was present in the "open" tooth category, whereas in 3 pairs, a periapical lesion was seen exclusively in the "intact" tooth. Though the odds-ratio for a lesion to be present in the "open group" was 3. 0, this was not a statistically significant result (P >.10).

CONCLUSIONS

Data suggest that the problem of coronal leakage may not be of such a great clinical importance as implicated by numerous studies in vitro, provided instrumentation and root fillings are carefully performed.