Sealing ability of mineral trioxide aggregate and super-EBA when used as furcation repair materials: a longitudinal study

Present status and future directions - Managing perforations

Root perforations are severe complications and are associated with compromised endodontic treatment outcomes, especially when bacterial infection is allowed to establish. Perforations may occur due to pathological processes or treatment consequences. Various dental materials have been proposed over the years for perforation repair with varying degrees of success. The use of bioactive materials, such as mineral trioxide aggregate (MTA) and other calcium-silicate cements, promotes a favourable environment for regeneration and has been used successfully for perforation repair. This is in contrast to materials used previously that often led to unpredictable outcomes. With the increasing range of new bioactive endodontic materials available, the number of potential materials being used for repair of root perforations is growing. Though promising to date, there is little evidence to support the use of most of these new materials. The aim of this narrative review is to provide the background, clinical techniques and outcome of nonsurgical and surgical perforation repair.

Volumetric Evaluation of Voids and Gaps of Different Calcium-Silicate Based Materials Used in Furcal Perforations: A Micro-CT Study

This study aimed at evaluating volumetrically gaps and voids of calcium-silicate based materials of different generations and handling properties (BC—Endosequence BC RRM-Fast Set Condensable Putty, MTA—ProRoot MTA, and BIO—Biodentine) in simulated furcal perforations in an ex vivo setup by microcomputed tomography (Micro-CT) analysis. Thirty-six extracted human mandibular molars with sound furcation areas were selected. Standardized perforations were created in the furcation area of the pulp chamber using #4 diamond burs. The specimens were randomly assigned to three groups (BC, MTA and BIO; n = 12). Samples were then scanned (SkyScan 1172; Bruker-microCT, Kontich, Belgium), and three-dimensional (3D) images reconstructed. The relative volume of gaps (VG%) and voids (VV%) present on each material was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s HSD test (p < 0.05). Mean VG% for BC, MTA, and BIO groups were, respectively, 0.513%, 1.128%, 1.460%, with BC presenting statistically (p < 0.05) fewer gaps formation than the other groups. Mean VV% were, respectively, 0.018%, 0.037%, and 0.065%. The was no statistical difference regarding VV%. There were no gap-free and void-free samples. BC group had the lowest VG% among the groups with a significant statistical difference (p < 0.05).

A Systematic Review Comparing Mineral Trioxide Aggregate to Other Commercially Available Direct Pulp Capping Agents in Dogs

Vital pulp therapy (VPT) and direct pulp capping (DPC) are procedures regularly performed in dogs for the management of acute tooth fractures and as part of management for traumatic malocclusions. The purpose of this review is to apply an evidence-based medicine approach to systematically review and evaluate the scientific literature evaluating the efficacy of mineral trioxide aggregate (MTA) to other commercially available materials used for VPT in the permanent teeth of dogs. The 9 studies meeting inclusion criteria were reviewed and each studies evidence was classified using a grading system modified from the Oxford Centre for Evidence-Based Medicine. For the studies meeting inclusion criteria, MTA consistently performed as well or better than other commercially available products in terms of calcific barrier formation and biocompatibility. This review found a lack of consistency between the studies making a direct comparison of the results unreliable. Future studies would benefit from the implementation of a standard scoring system for histology, equivalent and longer study duration times and the correlation of histological and radiographic data.

Nonsurgical Management of Strip Perforation Using Platelet-Rich Fibrin and MTA by Matrix Concept - A Case Report with One Year Follow-up

Iatrogenic errors happen especially during endodontic treatment even with the experienced clinicians. It is impossible to predict the occurrence of an event. Although many of them can be corrected and managed successfully, few conditions might have the worst prognosis leading to uneventful extraction. The present case report highlights a 1-year follow-up of managed strip perforation in mesial canals of mandibular first molar, nonsurgically using MTA obturation. The present challenging case gives an insight on the importance of regenerative capacity and osteogenic potentiality of bioactive materials, when appropriate tissue engineering concepts are applied.

The Response of the Pulp-Dentine Complex, PDL, and Bone to Three Calcium Silicate-Based Cements: A Histological Study in an Animal Rat Model

Objective

The aim of this study was to histologically examine the tissue reaction of three different calcium silicate cements in the closure of perforations in rat incisor teeth. Material and Methods. An experimental lateral root perforation with pulp exposure was performed in 32 lower incisors of 16 male Wistar albino rats. They were randomly assigned into three test groups (each including eight teeth) that were filled either by Biodentine (BD) or MicroMega mineral trioxide aggregate (MM-MTA) or EndoSequence root repair material putty (ESRRM putty), besides eight unperforated incisors from the other four rats (control group). The inflammatory response and healing process were evaluated histologically and scored after one and four weeks. Differences among groups were tested by Kruskal-Wallis tests at P ≤ 0.05.

Results

In the first week, BD produced more inflammatory response in the pulpal (score 3) than other materials (score 2). Only ESRRM putty showed odontoblast-like cells in 50%, 25% dentine-like deposit, 25% evidence of bone deposition in the drilling site (score 2), and minimum periodontal ligament (PDL) necrosis and disorganization (25%, score 2). After one month, all groups had healthy pulpal tissue, but 25% of ESRRM putty retained score 1 inflammatory response, and 50% of the BD case had an incomplete palisading odontoblast layer (score 3). A thick and regular dentine bridge deposition was seen in the ESRRM putty group in comparison with MM-MTA and BD cases. The cortical plate healing in all ESRRM putty samples was complete (score 3), while an incomplete closure was seen in MM-MTA and BD groups (score 2). Both the MM-MTA and ESRRM putty groups had fully organized PDL (score 2), while in 50% of BD cases, a necrotizing area and disorganized PDL with inflammatory cells infiltration were still present. Statistically significant differences in the scores of any histologic parameters among the three tested materials were observed neither in the 1st nor in the 4th weeks of the experimental period.

Conclusion

Better tissue compatibility and repair of pulpal and periodontal tissue have been detected after lateral perforation in the root of rat incisors when treated with ESRRM putty than MM-MTA and BD. However, the difference was not significant.

A review of the literature on the efficacy of mineral trioxide aggregate in conservative dentistry

The aim of this literature review was to assess the clinical performance of MTA to establish the evidence level for its effectiveness in vital pulp therapy, perforation repair, and retrograde root canal filling. A comprehensive literature survey was performed via electronic databases of PubMed/MEDLINE. A total of 58 papers were reviewed in this study, of which 2 were systematic reviews/meta-analysis, 9 were randomized controlled trials (RCTs), and the rest were fallen into other categories. Mineral trioxide aggregate (MTA) provided better pulp protection as a direct capping material when compared with calcium hydroxide. As perforation repair materials, MTA demonstrated an excellent sealing ability in vitro. For periodontal tissues around a perforation, MTA provided normal healing processes in clinical trials. It is therefore concluded that MTA has a high potential in repairing perforations. MTA is the most promising material when used for retrograde root canal filling demonstrating normal healing in short/long term clinical outcomes.

Effect of sodium hypochlorite and chlorhexidine irrigating solutions and their inactivating agents on the push-out bond strength of mineral trioxide aggregate

The objective of this study was to evaluate the effect of sodium hypochlorite and chlorhexidine solutions and their inactivating agents on the push-out bond strength of mineral trioxide aggregate (MTA). One hundred fifty root slices were prepared and their root canal spaces were enlarged using diamond burs. MTA was prepared and compacted to root canal spaces. The samples were randomly separated to 4 groups that would be immersed into the selected solutions (5.25% sodium hypochlorite (NaOCl), 5.25% NaOCl and sodium thiosulfate, 2% chlorhexidine (CHX), 2% CHX and a mixture of Tween 80 and 0.3% L-alfa-lecithin) and a control group (n = 30). Push-out bond strength of each specimen was tested with universal testing machine. The data was analyzed by one-way analysis of variance and Tukey tests. There were no significant differences between the push-out bond strength values of the irrigation groups and the control group. A significant difference was found between the push-out bond strength values of NaOCl-Sodium thiosulfate and CHX-L-alpha-lecithin groups. Contact with NaOCl and its neutralizing agent with MTA after 10 minutes of setting period increased the push-out bond strength of MTA. On the other hand, any contact with CHX alone or with subsequent application using L-alfa-lecithin should be avoided since that might decrease the push-out bond strength of freshly mixed MTA.

Successful Management of Teeth with Different Types of Endodontic-Periodontal Lesions

Endodontic-periodontal diseases often present great challenges to the clinician in their diagnosis, management, and prognosis. Understanding the disease process through cause-and-effect relationships between the pulp and supporting periodontal tissues with the aid of rational classifications leads to successful treatment outcomes. In this report, we present several treatment modalities in patients with different endodontic-periodontal lesions. A modification to the new endodontic-periodontic classification, Al-Fouzan's classification, was also added. The first case was classified as retrograde periodontal disease (i.e., primary endodontic lesion with drainage through the periodontal ligament). The second case was diagnosed as an iatrogenic periodontal lesion caused by root perforation. The third case was diagnosed as an iatrogenic periodontal lesion caused by tooth trauma due to orthodontic treatment. The first two cases were managed with a nonsurgical approach, whereas the third case was managed with nonsurgical and surgical approaches. All patients showed complete healing of soft and hard tissue lesions. A thorough understanding of the disease history and the patient's signs and symptoms, complete examination with full investigation, and the use of a systematic step-by-step approach in the management of such challenging endodontic-periodontal lesions with regular recall visits were very useful and successful.

Animal models used in furcation perforation studies: A systematic review and comprehensive synthesis of model characteristics

In order to systematise furcation perforation (FP) experimental animal models described in the literature and to determine whether there is evidence that a model is superior to others, MEDLINE/PubMed, SciELO and Cochrane Library were searched to find studies which used animal models of FP. Data were gathered concerning model characteristics, chosen groups, sample numbers, type of outcomes, journal and main area studied. Twenty-five articles were included in this systematic review, four conducted in rodent models, three in non-human primates and 18 in dogs. Medians were six animals and 34 teeth per study; 10 teeth per test group and, when performed, six teeth per control group. Twenty-four studies investigated the use of materials for FP repair; eight also tested adjuvant materials/substances. Although there is no model which can be described as ideal and superior than others for FP studies, dogs appear to possess the most suitable model characteristics.

Behavior of mineral trioxide aggregate apical plugs and root fillings under cyclic loading

AIM

The aim of the present study was to develop a methodology for constant monitoring of the resistance to fluid flow during functional loading and to then compare the efficacy of 4-mm mineral trioxide aggregate (MTA) apical plugs and full-length MTA root fillings.

METHODS

The root canals of 24 single-rooted teeth were instrumented and assigned into two groups: group 1 (filled with a 4-mm MTA apical plug and gutta percha) and group 2 (filled with MTA to cementoenamel junction level). All teeth were subjected to stepwise cyclic loading with a constant simulated interstitial pressure of 25 cm H₂ O applied apically. A Flodec machine (De Marco Engineering, Geneva, Switzerland) constantly monitored the rate and direction of fluid flow. Student's t-test, Kruskal-Wallis test, Fisher's exact test, and Newcombe-Wilson test were used for statistical analysis, with P < 0.05.

RESULTS

Crown fractures occurred in 21 teeth with no change in the rate of fluid flow. Three teeth (filled with full-length MTA) showed sudden change in the rate of fluid flow through the root canal after cyclic loading.

CONCLUSIONS

The methodology reliably monitored fluid flow during cyclic loading. There was no difference between a 4-mm MTA apical plug and full-length MTA root filling after cyclic loading using a dynamic fluid-flow monitoring technique.

Comparison of Tooth Discoloration Induced by Calcium-Enriched Mixture and Mineral Trioxide Aggregate

Introduction:

The aim of this in vitro study was to evaluate the tooth discoloration induced by calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA).

Methods and Materials:

Forty five endodontically treated human maxillary central incisors were selected and divided into three groups (n=15) after removing the coronal 3 mm of the obturating materials. In the MTA group, white MTA plug was placed in pulp chamber and coronal zone of the root canal. In CEM cement group, CEM plug was placed in the tooth in the same manner. In both groups, a wet cotton pellet was placed in the access cavity and the teeth were temporarily sealed. After 24 h the teeth were restored with resin composite. In the negative control group the teeth were also restored with resin composite. The color change in the cervical third of teeth was measured with a colorimeter and was repeated 3 times for each specimen. The teeth were kept in artificial saliva for 6 months. After this period, the color change was measured again. Data were collected by Commission International de I'Eclairage's L*a*b color values, and corresponding ΔE values were calculated. The results were analyzed using the one-way ANOVA and post-hoc Tukey’s test with the significance level defined as 0.05.

Results:

There was no significant differences between CEM group and control group in mean discoloration. The mean tooth discoloration in MTA group was significantly greater than CEM and control groups (P<0.05).

Conclusion:

According to the result of the present study CEM cement did not induce tooth discoloration after six months. Therefore it can be used in vital pulp therapy of esthetically sensitive teeth.

A Review on Perforation Repair Materials

Perforation is an artificial communication between the root canal system and supporting tissues of the teeth. Root perforation complicates the treatment and deprives the prognosis if not properly managed. A wide variety of materials to seal the perforations have been suggested in literature. There are many comparative studies showing the efficacy of one material over the other. Literature shows many reviews on diagnosis, treatment plan and factors affecting prognosis of perforation repair; but none of these articles elaborated upon various materials available to seal the perforation. The present article aims at describing all the materials used for perforation repair from the past till date; it also offers a literature review of all the articles published over last four decades referred to the treatment of perforation with various root repair materials.

Boon of MTA Apexification in Young Permanent Posterior Teeth

Single visit apexification using mineral trioxide aggregate (MTA) is a new boon in effective management of nonvital tooth with an open apex which has steadily gained popularity with clinicians; also it shortens the treatment period and improves patient compliance. Importance of this approach lies in expedient cleaning and shaping of the root canal system, followed by its apical seal with MTA. There are several case reports available describing the use of MTA as an apexification agent in incisors and premolar, but presented cases are the unique case reports demonstrating successful apexification procedure using MTA in young permanent mandibular molars. After eight-month follow-up, teeth were without any abnormal clinical symptoms; rather there were radiographic resolution of the periapical lesion and induction of root end closure with new hard tissue formation over MTA.

Tooth discoloration after the use of new pozzolan cement (Endocem) and mineral trioxide aggregate and the effects of internal bleaching

INTRODUCTION

The aim of this study was to evaluate tooth discoloration after the use of mineral trioxide aggregate (MTA) and to examine the effect of internal bleaching on discoloration associated with MTA.

METHODS

Thirty-two teeth were endodontically treated. Three-millimeter plugs of MTA, ProRoot, Angelus, or Endocem were placed on the access cavities of 24 teeth. Eight teeth served as the control group. After 24 hours, the access cavities were restored, and the tooth color was recorded at baseline and at 1, 2, 4, 8, and 12 weeks. After 12 weeks, the MTA materials were removed under a microscope, and an internal bleaching treatment was performed. After removal of the MTA materials and after a 1-week bleaching treatment, the color changes were measured, and the MTA-dentin interfaces were observed under a microscope.

RESULTS

The ProRoot and Angelus groups displayed increasing discoloration during a period of 12 weeks. The discoloration associated with ProRoot and Angelus was observed at the MTA-dentin interface and on the interior surface of the dentin. However, the Endocem groups demonstrated no significant discoloration (P < .05). No marginal discoloration was observed around the material in the Endocem group. Removal of the discolored MTA was effective for resolving the discoloration in all of the experimental groups (P < .05). However, a subsequent internal bleaching treatment was not significantly effective compared with the removal of MTA.

CONCLUSIONS

ProRoot and Angelus caused tooth discoloration. However, Endocem did not affect the contacting dentin surface. Removing the discolored MTA materials contributed more to resolving the tooth discoloration than post-treatment internal bleaching.

Comparison of sealing ability of bioactive bone cement, mineral trioxide aggregate and Super EBA as furcation repair materials: A dye extraction study

CONTEXT

Sealing ability of furcation repair material.

AIMS

To evaluate the sealing ability of bioactive bone cement, mineral trioxide aggregate (MTA) and Super Ethoxybenzoic Acid (EBA) as furcation repair materials in mandibular molars using a dye extraction leakage model.

SETTINGS AND DESIGN

In vitro, dye extraction study.

MATERIALS AND METHODS

FORTY MANDIBULAR MOLARS WERE RANDOMLY DIVIDED ACCORDING TO THE MATERIAL USED TO REPAIR PERFORATION: Group I-MTA, Group II-bioactive bone cement, Group III-Super EBA, Group IV-Control (furcation left unrepaired). All samples were subject to ortho grade and retrograde methylene blue dye challenge followed by dye extraction with 65% nitric acid. Samples were then analyzed using Ultra violet (UV) Visible Spectrophotometer.

STATISTICAL ANALYSIS USED

One way analysis of variance (ANOVA), Tukey-Kramer Multiple Comparisons Test.

RESULTS

MTA and bioactive bone cement showed almost similar and lower absorbance values in comparison to Super EBA.

CONCLUSIONS

Bioactive bone cement provi ded an excellent seal for furcal perforation repair and at the same time it provided comfortable handling properties, which could overcome the potential disadvantages as faced with MTA.

Analysis of six heavy metals in Ortho mineral trioxide aggregate and ProRoot mineral trioxide aggregate by inductively coupled plasma-optical emission spectrometry

Ortho mineral trioxide aggregate (MTA) is a mineral aggregate newly developed for perforation repair, root end filling and pulp capping. The aim of this study was to investigate the levels of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) in Ortho MTA and ProRoot MTA. A total of 0.2 g of each MTA was digested using a mixture of hydrochloric and nitric acids and filtered. Six heavy metals in the resulting filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (n = 5). The results were statistically analyzed using the Mann-Whitney U-test. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in Ortho MTA were 0.10, 7.73, 49.51, 2.58, 0.82 and 10.09 p.p.m., respectively. The concentrations of Cd, Cu, Fe, Mn, Ni and Zn in ProRoot MTA were 0.16, 9.38, 1438.11, 74.51, 18.98 and 4.05 p.p.m., respectively. In conclusion, Ortho MTA had lower levels of Cd, Cu, Fe, Mn and Ni than ProRoot MTA.

Periradicular Tissue Responses to Biologically Active Molecules or MTA When Applied in Furcal Perforation of Dogs' Teeth

The aim of this study was the comparative evaluation of inflammatory reactions and tissue responses to four growth factors, or mineral trioxide aggregate (MTA), or a zinc-oxide-eugenol-based cement (IRM) as controls, when used for the repair of furcal perforations in dogs' teeth. Results showed significantly higher inflammatory cell response in the transforming growth factorβ1 (TGFβ1) and zinc-oxide-eugenol-based cement (IRM) groups and higher rates of epithelial proliferation in the TGFβ1, basic fibroblast growth factor (bFGF), and insulin growth factor-I (IGF-I) groups compared to the MTA. Significantly higher rates of bone formation were found in the control groups compared to the osteogenic protein-1 (OP-1). Significantly higher rates of cementum formation were observed in the IGF-I and bFGF groups compared to the IRM. None of the biologically active molecules can be suggested for repairing furcal perforations, despite the fact that growth factors exerted a clear stimulatory effect on cementum formation and inhibited collagen capsule formation. MTA exhibited better results than the growth factors.

Effect of internal matrices of hydroxyapatite and calcium sulfate on the sealing ability of mineral trioxide aggregate and light cured glass ionomer cement

Objective:

The present study was undertaken to evaluate the effect of hydroxyapatite (HA) and calcium sulfate (CS) on the sealing ability of mineral trioxide aggregate (MTA) and light cured glass ionomer cement (LC GIC) when used to repair furcation perforations.

Materials and Methods:

The study was conducted on 70 human molars. Sixty teeth with furcal perforations were randomly divided into six groups of 10 teeth each and repaired with MTA or LC GIC either alone or over an internal matrix, i.e., CS or HA. Access openings were filled with composite resin. Five teeth with unrepaired perforations were used as positive controls and five teeth without perforations were used as negative controls. The teeth were immersed in a solution of 2% methylene blue dye for 2 weeks. The samples were then sectioned and evaluated for linear dye leakage and analyzed statistically.

Results:

MTA showed the best sealing ability followed by LC GIC, MTA + CS, MTA + HA, LC GIC + CS and LC GIC + HA.

Conclusion:

Neither of the two internal matrices improved the sealing ability of the repair materials used.

Nonsurgical approach for strip perforation repair using mineral trioxide aggregate

“Stripping” is lateral perforation is caused by overinstrumentation through a thin wall in the root and is most likely to occur at the inside wall of a curved canal, such as the distal wall of the mesial roots in mandibular first molars. In the past, poor prognosis for strip and furcation perforations was probably due to bacterial leakage or lack of biocompatibility of repair materials. However, the recent development in the techniques and materials such as mineral trioxide aggregate (MTA) has enhanced the prognosis for such cases. There is limited literature on use of MTA as an obturating material in the treatment of strip perforation. This study presents two cases of strip perforation that are successfully repaired nonsurgically using MTA with 2-year follow up. Cases suggest that MTA can be used as an alternative root canal obturation material for the treatment of strip perforation. The property differences between gray and white MTA are reviewed.

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.

Bioactive materials in endodontics

Endodontic treatment in dentistry is a delicate procedure and many treatment attempts fail. Despite constant development of new root canal filling techniques, the clinician is confronted with both a complex root canal system and the use of filling materials that are harmful for periapical tissues. This paper evaluates reported studies on biomaterials used in endodontics, including calcium hydroxide, mineral trioxide aggregate, calcium phosphate ceramics and calcium phosphate cements. Special emphasis is made on promising new biomaterials, such as injectable bone substitute and injectable calcium phosphate cements. These materials, which combine biocompatibility, bioactivity and rheological properties, could be good alternatives in endodontics as root canal fillers. They could also be used as drug-delivery vehicles (e.g., for antibiotics and growth factors) or as scaffolds in pulp tissue engineering.

In vitro evaluation of the sealing ability of MTA used for the repair of furcation perforations with and without the use of an internal matrix

OBJECTIVE

To evaluate the effect of matrix on mineral trioxide aggregate (MTA) when used to repair furcal perforations.

STUDY DESIGN

Forty-five human molars with furcal perforations were randomly divided into 3 groups and repaired with MTA either alone or over a barrier (calcium sulfate or Collaplug). Eight teeth without perforations provided negative control samples. After assessing repair quality, 1 mol/L glucose solution was used as the tracer to detect the leakage. The concentration of leaked glucose was measured after 1, 2, 4, 7, 15, and 20 days using a glucose oxidase method.

RESULTS

No significant difference in either leakage or overfilling was found between the groups with Collaplug and MTA alone (P > .05). Although no overfilling was detected in the group with calcium sulfate, that group had the most leakage (P < .05).

CONCLUSIONS

Neither of the 2 internal matrices improved the sealing ability and reduced the incidence of overfilling simultaneously.

Reaction of the Lateral Periodontium of Dogs’ Teeth to Contaminated and Noncontaminated Perforations Filled with Mineral Trioxide Aggregate

It has been shown that the mineral trioxide aggregate (MTA) used to seal lateral/furcal perforations stimulates the deposition of newly formed cementum. Nevertheless, when the site of the perforation is contaminated, the healing process might occur under less favorable conditions. This study evaluated the repair healing process of noncontaminated and contaminated lateral perforations filled with MTA and the effect of previously filling the contaminated perforations with a bactericidal agent. Thirty lateral root perforations were prepared in endodontically treated dog's teeth, thus forming 3 groups with 10 specimens each. In group 1 the perforations were immediately sealed with MTA. In group 2 the perforations were left open for 7 days and thereafter sealed with MTA. In group 3 the perforations were left open for 7 days, filled temporarily with a calcium hydroxide-based paste for 14 days, and then sealed with MTA. The animals were killed after 90 days, and the pieces were prepared for histomorphologic and histomicrobiologic evaluations. The statistical analysis showed that group 1 had significantly better repair than groups 2 (P < .05) and 3 (P < .05), which validates the superior results obtained when MTA was immediately used to seal root perforations. Groups 2 and 3 had statistically similar repair to each other (P > .05). There were a larger number of cases of complete or partial biologic seal in group 1 compared with the contaminated groups. It might be concluded that the lateral root perforations sealed with MTA after contamination presented worse repair than the noncontaminated, immediately sealed perforations. The temporary filling with a bactericidal agent (calcium hydroxide-based paste) did not improve the repair of perforations exposed to contamination, and the contaminated groups presented similar results to each other.

Effects of EDTA on the hydration mechanism of mineral trioxide aggregate

Ethylenediaminetetraacetic acid (EDTA) is commonly used during the preparation of obstructed root canals that face a high risk of root perforation. Such perforations may be repaired with mineral trioxide aggregate (MTA). Due to EDTA's ability to chelate calcium ions, we hypothesized that EDTA may disrupt the hydration of MTA. Using scanning electron microscopy and energy-dispersive x-ray spectroscopy, we found that MTA specimens stored in an EDTA solution had no crystalline structure and a Ca/Si molar ratio considerably lower than those obtained for specimens stored in distilled water and normal saline. Poor cell adhesion in EDTA-treated MTA was also noted. X-ray diffraction indicated that the peak corresponding to portlandite, which is normally present in hydrated MTA, was not shown in the EDTA group. The microhardness of EDTA-treated specimens was also significantly reduced (p < 0.0001). These findings suggest that EDTA interferes with the hydration of MTA, resulting in decreased hardness and poor biocompatibility.

Evaluation of the formocresol versus mineral trioxide aggregate primary molar pulpotomy: a meta-analysis

OBJECTIVE

To apply meta-analysis to compare the clinical and radiographic effects of mineral trioxide aggregate (MTA) with formocresol (FC) when used as wound dressing for pulpotomy of primary molars.

STUDY DESIGN

The study list was obtained by searching MEDLINE, The Cochrane Library, EMBASE, and SCI. Only those papers that met the inclusion criteria were analyzed.

RESULTS

Six studies met the inclusion criteria. There was significant difference between the success rates of FC- and MTA-treated pulpotomized primary molars (P < .05). Clinical assessments and radiographic findings of the MTA versus FC pulpotomy suggested that MTA was superior to FC in pulpotomy resulting in a lower failure rate, with the RR (Relative Risk) being 0.32 (95% confidence interval [CI] 0.11 to 0.90) and 0.31 (95% CI 0.13 to 0.74), respectively. Internal root resorption happened less in the MTA group with RR 0.29, 95% CI 0.11 to 0.77.

CONCLUSION

MTA induces less undesirable responses and might be FC's suitable replacement.

Healing of root perforations treated with Mineral Trioxide Aggregate (MTA) and Portland cement

Fourteen root perforations were performed for microscopic evaluation of the repair of interradicular tissue in dogs' teeth. These perforations were accomplished at low-speed with a STP 58 bur at the cervical third of the mesial root toward the furcation under irrigation with saline solution, followed by immediate sealing with ProRoot MTA, MTA-Angelus and white Portland cement. The dogs were killed after 90 days, revealing good results. The Kruskal-Wallis test did not demonstrate any statistically significant difference. It was concluded that the three materials showed good sealing in mineralized tissue, with complete closure, and they were free of inflammation in most teeth.

Effect of mineral trioxide aggregate on proliferation of cultured human dental pulp cells

AIM

To investigate the effect of mineral trioxide aggregate (MTA) on the proliferation of human dental pulp (HDP) cells ex-vivo.

METHODOLOGY

Human dental pulp cells were cultured with MTA or calcium hydroxide-containing cement (Dycal) using culture plate inserts. Control cells were cultured with culture plate inserts only. Cell proliferation was measured for up to 14 days using a Cell Counting kit, and the concentration of calcium ions released from the tested materials was assessed using a Calcium E-test kit. To confirm that the effect of MTA was attributable to released calcium ions, cell proliferation was measured in the presence of exogenous calcium chloride as a source of calcium ions while in the absence of MTA.

RESULTS

Mineral trioxide aggregate significantly stimulated cell proliferation after 12 days, whereas Dycal had no such effect. The number of calcium ions released from MTA was significantly higher than that released from Dycal. Following the addition of calcium chloride, cell proliferation increased in a dose-dependent manner after 12 days. Moreover, cell proliferation showed a similar pattern whether a given concentration of calcium ions was produced by calcium chloride or by release from MTA.

CONCLUSIONS

In this ex-vivo study, the elution components such as calcium ions from MTA had higher proliferation ability of HDP cells than control and Dycal.

Furcation Perforation Repair Comparing Gray and White MTA: A Dye Extraction Study

The purpose of this study was to evaluate the ability of gray and white ProRoot MTA to seal furcation perforations in mandibular molars using a dye extraction leakage model. Sixty-four mandibular molars were randomly divided into four experimental groups. Six teeth with perforations were used as positive controls and six teeth without perforations were used as negative controls. Perforations in groups 1 and 2 were repaired with white MTA. Groups 3 and 4 were repaired with gray MTA. Dye leakage was tested from an orthograde direction (groups 1 and 3) and a retrograde direction (groups 2 and 4). After dye extraction, absorbance was measured on a spectrophotometer at 550 nm. No statistically significant difference in leakage was found between gray and white MTA when used as a furcation perforation repair material. However, there was significantly more leakage when the perforations were challenged from the orthograde than the retrograde direction (p < 0.001).

Leakage of Bovine Serum Albumin in Root Canals Obturated with Super-EBA and IRM

The aim of this study was to determine the leakage of SuperEBA and intermediate restorative material (IRM) in root canal samples, with or without orthograde filling, by evaluating bovine serum albumin (BSA) microleakage using spectrophotometry. Thirty-five single-rooted teeth were divided into five groups, instrumented, and had apices resected. Root-end cavities in groups I and II were filled with SuperEBA and IRM. The samples from the groups III, IV, and V were filled with gutta-percha and sealer. In groups IV and V, root-end cavities were filled with SuperEBA and IRM. After 60 days, the greatest microleakage of BSA was observed in group II (4.1 +/- 0.0011 ng), followed by group III (3.4 +/- 0.0064 ng), and then group I (2.6 +/- 0.0019 ng). Samples from groups IV and V leaked the least (0.7 +/- 0.0014 ng). Significantly less leakage (p < 0.05) occurred in samples filled with orthograde and root-end fillings than did in samples filled only with an orthograde approach and the samples with IRM root-end fillings.

Properties of a new root-end filling material

The purposes of this investigation were 2-fold: to study the physical properties and sealing ability of Viscosity Enhanced Root Repair Material (VERRM); and, to compare them with Mineral Trioxide Aggregate (MTA). VERRM has a composition similar to mineral trioxide aggregate, with handling characteristics and consistency similar to commercially available materials such as IRM and Super EBA. The pH, setting times, solubility, radiopacity, dimensional change upon setting, and apical sealing ability of VERRM were evaluated and compared to that of ProRoot MTA (GMTA) and ProRoot MTA (Tooth Colored Formula) (WMTA). The results showed that VERRM had physical properties similar to WMTA. VERRM and WMTA showed significantly greater dye penetration than GMTA (p < 0.05) when used as a root-end filling material. There was no significant difference in depth of dye penetration between VERRM and WMTA. Further development of VERRM is indicated to produce a biocompatible root-end filling material with superior handling characteristics.

Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

Histologic study of furcation perforations treated with MTA or Super EBA in dogs' teeth

OBJECTIVE

The aim of this study was to investigate the histologic response to MTA or Super EBA when used for the repair of furcation perforations in dogs' teeth.

STUDY DESIGN

Ninety mandibular premolar and molar teeth of 9 mongrel dogs were used in this study. The teeth were divided into 3 groups. Seventy-two teeth were repaired with either MTA or Super EBA (36 each), and 18 teeth were not repaired and used as negative controls. All groups were histologically examined at 1 month, 3 months, and 6 months after treatment. Histologic evaluation was done with regard to inflammation and type of healing.

RESULTS

The Super EBA group showed moderate inflammation in 1 month; the inflammation decreased over time, but most of specimens showed inflammatory reaction from mild to severe at the end of 6 months. The perforation area was filled by connective tissue in specimens in which no inflammation was seen. In the MTA group, mild inflammation was seen in 1 month, it decreased in 3 months, and no inflammation was detected in 6 months. New cementum formation was taken in place in 4 specimens in 1 month, in 8 specimens in 3 months, and in all specimens in 6 months.

CONCLUSIONS

MTA showed less inflammation than Super EBA. MTA specimens showed healing with new cementum formation in the perforation area, whereas Super EBA specimens in which no inflammation was seen showed connective tissue healing.

Effect of ProRoot MTA on Pulp Cell Apoptosis and Proliferation In Vitro

ProRoot Mineral Trioxide Aggregate (MTA) has been indicated as a pulp capping material. The purpose of this study was to evaluate the effect of tooth-colored (white) MTA on pulp cell apoptosis and cell cycle. Mouse odontoblast-like cells (MDPC-23) and undifferentiated pulp cells (OD-21) were exposed to 0 to 100 mg MTA for 24 h. Propidium iodide staining followed by flow cytometry demonstrated that MTA did not induce apoptosis of MDPC-23 or OD-21 (p > 0.05). Cell cycle analysis showed that MTA induced a modest (but significant) increase in the percentage of MDPC-23 in the S and G2 phases, and OD-21 in the S phase of cell cycle, as compared to untreated controls (p </= 0.05). In conclusion, MTA induced proliferation, and not apoptosis, of pulp cells in vitro. These findings suggest a potential mechanism to explain the regenerative effect observed in the dentin-pulp complex when MTA was used for direct pulp capping.

MTA Obturation of Pulpless Teeth with Open Apices: Bacterial Leakage as Detected by Polymerase Chain Reaction Assay

Polymerase chain reaction (PCR) followed by reverse dot blot was used to detect Enterococcus faecalis leakage through mineral trioxide aggregate (MTA) apical obturations of pulpless teeth with open apices. Prepared root canals of 34 extracted teeth were given a standard apical foramen opening and received orthograde apical obturation with MTA; three groups had 1-, 2-, or 3-mm thickness. Sterilized specimens were inoculated with E. faecalis and incubated in sterile medium. DNA extracted from the specimens was amplified by polymerase chain reaction, which yielded a specific segment of E. faecalis 16S rDNA. On day 10 of incubation, no specimens were contaminated. On day 50, almost 17% of specimens were contaminated, with no statistically significant difference between groups (Chi-square = 0.48; df = 2; p = 0.787). Therefore, MTA provides an adequate seal even in cases of orthograde apical obturation of pulpless teeth with open apices.