In-Vitro Evaluation of Microleakage of an Orthograde Apical Plug of Mineral Trioxide Aggregate in Permanent Teeth with Simulated Immature Apices

Evaluation of Microleakage of Orthograde Root-Filling Materials in Immature Permanent Teeth: An In Vitro Study

Introduction: The absence of a barrier in an open root apex makes endodontic treatment challenging as root-filling material can easily reach the surrounding tissue. The aim of the study was to compare the apical microleakage associated with mineral trioxide aggregate (MTA), biodentine, custom-made gutta-percha with MTA plus and custom-made gutta-percha with Adseal in immature permanent teeth by dye penetration method. Methods: Apical 2 mm of 60 single-rooted mandibular premolar teeth was resected to create divergent open apices and 10 teeth each were filled with Biodentine plug, MTA plug, custom-made gutta-percha with MTA plus sealer and custom-made gutta-percha with Adseal sealer. Ten teeth each acted as positive and negative controls. All the samples were stored at 37°C at 100% humidity for 5 weeks and then immersed in 2% Rhodamine B dye for 24 h. Transverse sectioning was done apically at 1 mm and 3 mm to evaluate dye penetration under a fluorescence microscope using ImageJ software. Results: There was a significantly greater microleakage at 1 mm cross section compared to 3 mm (p < 0.0001). At 1 mm cross section, the apical microleakage was the highest for the MTA plug with a mean leakage percentage of 48.08 ± 16.38, a mean depth of leakage of 0.46 ± 0.10 mm and a mean area of leakage of 1.35 ± 0.74 mm2, compared to other groups, and the difference was statistically significant. However, at a 3 mm cross section, MTA plus sealer with gutta-percha demonstrated the highest mean leakage percentage (25.01 ± 7.77) compared to other groups and the difference was statistically significant (p = 0.03). Conclusion: It can be concluded that the 3-mm-thick apical plug provided better sealing of the open apex compared to the 1 mm apical plug and there was no significant difference in microleakage among the Biodentine plug, MTA plug and Adseal sealer with gutta-percha plug at 3 mm cross section.

Mineral trioxide aggregate obturation quality with two obturation techniques in severe curved root canals - a micro-CT study

BACKGROUND

The existence of voids within the mineral trioxide aggregate (MTA) composition is one of the factors that can influence the treatment outcome. The primary objective of this study was to quantitatively assess and compare the MTA orthograde obturation quality in severe curved root canals using two different MTA compaction techniques: manual compaction with K-file, or Auger technique using micro-computed tomography (micro-CT) imaging.

METHODS

For this study, 26 mandibular first molar teeth with severely curved mesiobuccal root canals were selected. These samples were randomly divided into two groups. All root canals were instrumented using ProTaper Gold rotary files up to the F3 file at the working length. In one group, OrthoMTA was compacted using a stainless steel K-file, while in the other group, the Auger technique was employed for compaction into the root canals. Once the MTA had completely set, the filled root canals were subjected to scanning using a high-resolution micro-CT scanner. The porosity volume was determined as a percentage in relation to the overal volume of the canal, and the collected data were subjected to analysis using SPSS software, with the significance level set at P < 0.05.

RESULTS

The two techniques had no significant difference in open, closed, and total mean porosity. In both groups, the mean of open porosity was significantly more than closed porosity.

CONCLUSIONS

According to the results of the present study, neither of these two techniques is preferred to the other, and factors such as working time, etc., can be considered to choose the more appropriate clinical technique.

In vitro bacterial penetration and dissemination through dentinal tubules in roots filled with calcium silicate-based cements

The aim of this study was to assess whether calcium silicate root fillings prevent bacterial penetration and to determine how bacteria penetrate roots. Extracted single-rooted, single-canal human teeth were decoronated, prepared and filled with ProRootMTA or Biodentine (n = 12 each). Positive and negative (n = 2 each) controls were not filled. A two-chamber model was used with Streptococcus gordonii. The lower compartment was evaluated for turbidity over 150 days. Roots were split and examined for bacteria via SEM. The chi-squared test was used for comparisons (α = 0.05). Experimental groups had bacteria in their coronal thirds. Tubules contained bacteria in 90.9% and 91.7% of areas examined in the Biodentine and ProRootMTA groups, respectively, with no significant difference (p = 0.914). Experimental and negative roots had no turbidity with no significant difference between Biodentine and ProRootMTA (p = 1.000). Positive controls had turbidity. Bacteria penetrate roots via dentine tubules of root-filled teeth. Biodentine was comparable to ProRoot MTA.

Effects of Access Cavity Design and Placement Techniques on Mineral Trioxide Aggregate Obturation Quality in Simulated Immature Teeth: A Micro-Computed Tomography Study

Background and Objectives: In teeth with open apices, performing single session apexification is a challenging treatment due to the difficulty in handling mineral trioxide aggregate (MTA). Minimally invasive approaches in dentistry have also influenced the cavity designs in endodontics. Until now, different techniques have not been investigated in addition to manual condensation during the process of placing MTA in traditional (TradACs) or conservative (ConsACs) endodontic access cavities. The aim of this in vitro study was to compare and evaluate the obturation quality of MTA apical plugs placed with different techniques in TradACs or ConsACs. Materials and Methods: Sixty upper central teeth were divided into two main groups based on cavity design, and then each main group was further divided into three subgroups according to MTA placement techniques (n = 10): TradAC-manual, TradAC-manual + indirect ultrasonic activation, TradAC-manual + XP-endo Shaper (XPS), ConsAC-manual, ConsAC-manual + indirect ultrasonic activation, and ConsAC-manual + XPS. Subsequently, the porosity percentages in the MTA apical plug were analyzed using micro-computed tomography. The statistical analysis was performed using the Kruskal-Wallis H test and Mann-Whitney U test. Statistical significance was set at p < 0.05. Results: There were differences in volume of porosity percentages (%) according to cavity designs and MTA application techniques (p < 0.05). Except for the XPS group, more porosity was observed in ConsACs compared to TradACs. In TradACs, the significantly lowest open and total porosity was observed in the manual, ultrasonic, and XPS techniques, respectively. In ConsACs, the significantly lowest porosity was observed in the manual, XPS, and ultrasonic techniques, respectively (p < 0.05). Conclusions: In MTA obturation, cavity designs and application techniques had an impact on the MTA porosity. Creating an apical plug in ConsACs may result in more porosity compared to TradACs, especially when manual or indirect ultrasonic activation is preferred. Opting for the manual technique alone may be considered sufficient for controlling porosity for both TradACs and ConsACs.

Effects of Apical Barriers and Root Filling Materials on Stress Distribution in Immature Teeth: Finite Element Analysis Study

PURPOSE

A finite element analysis (FEA) study was performed to determine whether the material of apical barrier used for root apexification and/or the use of canal reinforcement affect the stress distribution in an endodontically treated immature permanent tooth in order to infer in which clinical scenarios a fracture is more likely to occur based on the ultimate tensile strength threshold of dentin.

METHODS AND MATERIALS

An extracted human immature mandibular premolar was selected as the reference model and scanned by micro-computed tomography (micro-CT). The digital model was segmented and converted to STL (Standard Tessellation Language) using Simpleware Scan-IP and exported in IGES (Initial Graphics Exchange Specification) to Ansys 19. Six experimental models were designed with different combinations of composite, mineral trioxide aggregate (MTA), and Biodentine (BIO). Using FEA, a static 300N load at a 135 angle with respect to the axis of the tooth was applied to each model and Von-Mises stress values (MPa) were measured at the sagittal, apical 8mm, 5mm, 2mm, and 1mm levels.

RESULTS

In all regions examined, the control (NT model) had lower stress in the root compared to experimental models. At the mid-root level, models with composite, MTA, and BIO reinforcement exhibited lower stresses in the root dentin than those with pulp or gutta-percha. BIO models had equal or greater average Von-Mises stress values than those of MTA models in all regions. Both, MTA and BIO, caused increases in stress of surrounding root dentin, with BIO causing a greater increase than MTA.

CONCLUSIONS

Stress distribution in immature permanent teeth treated by apexification is affected by the types of materials used. Root dentin's stress was lower when the mid-root canal was reinforced by composite, MTA, or BIO, which provided similar stress reduction to the root dentin. MTA is a more favorable apical barrier material from a mechanical standpoint because it induces less stress on apical root dentin than BIO.

Surface Microstructure of Two Bioceramics: Calcium-Enriched Mixture and Cold Ceramic in Setting Environments with Different pH Values

Introduction

The pH of the setting environment could alter the surface characteristics of bioceramics. The present study aimed to assess the surface microstructure of calcium-enriched mixture (CEM cement) and cold ceramic (CC) in setting environments with different pH values.

Materials and Methods

12 dentin blocks with 3 mm height and internal diameter were prepared. CEM cement and CC were prepared and packed into the blocks. Samples in each bioceramics group (n = 6) were divided into 3 subgroups (n = 2) and exposed to acid, pH of 7.4, and alkaline pH for 1 week. Specimens were prepared for evaluation under a scanning electron microscope using backscattered electron (BSE) detectors. Monitoring of pH changes was rendered with a pH meter through the setting process.

Results

BSE detection in an acidic environment showed more amorphous microstructures in CC specimens in comparison to CEM cement. In pH of 7.4 and alkaline pH, more unhydrated structures were observed in CEM cement compared with CC samples. During the first 48 h of the setting process, the pH changes of setting environments were more rapid in the CEM cement group in comparison to CC samples.

Conclusion

pH changes during the setting process of cement could affect the surface microstructure and physical properties. In acidic environments, the crystallization of CC cement is more disrupted than that of CEM cement.

Apical Sealing Ability of Two Calcium Silicate-Based Sealers Using a Radioactive Isotope Method: An In Vitro Apexification Model

The aim of this study was to evaluate and compare the sealing ability of two calcium silicate-based sealers (TotalFill BC RRM Fast Set Putty and White ProRoot MTA) when used as apical plugs in immature teeth through nuclear medicine. Single-rooted extracted teeth (n = 34) had their crowns and root tip sectioned to obtain 14 mm long root segments to simulate an in vitro apexification model. Were created two experimental groups, namely MTA (n = 12) and BC (n = 12), and two control groups, PG (positive group, n = 5) and NG (negative group, n = 5). On the 4th day after placing the respective apical plug, the apical portions of the teeth were submerged in a solution of sodium pertechnetate (^99mTcNaO₄) for 3 h. Statistical analysis showed a significant difference between the MTA group and the controls (p < 0.05). The BC group had a significant difference regarding the negative control (p < 0.001) but showed no statistical significance regarding the positive control (p = 0.168). There was a statistically significant difference (p = 0.009) between the BC group (7335.8 ± 2755.5) and the MTA group (4059.1 ± 1231.1), where the last showed less infiltration. Within the limitations of this study, White ProRoot MTA had a significantly better sealing ability than TotalFill BC RRM Fast Set Putty.

Bioactive Materials for Direct and Indirect Restorations: Concepts and Applications

Currently, minimally invasive restorations could be made in dentistry applying adhesive materials and adhesion principles to the dental structures. Following this philosophy, endodontic interventions have been avoided largely, preserving hard tissues, and maintaining dental vitality. Advances in biologically favorable bioactive materials enabled clinicans to induce repair and regeneration of dental tissues. Such materials are primarily used for pulp protection and cementation of indirect restorations. This review highlights current bioactive materials available, principles of bioactivity and their mechanisms of action.

Comparative Evaluation of Mineral Trioxide Aggregate Obturation Using Four Different Techniques-A Laboratory Study

This study aimed to compare the density of mineral trioxide aggregate (MTA) as a root canal filling material in the apical 5 mm of artificial root canals. Forty transparent acrylic blocks with 30-degree curved canals were instrumented and allocated into four compaction technique groups (n = 10): Lawaty (hand files); gutta-percha (GP) points; auger (nickel–titanium rotary files in reverse mode); and plugger technique. Filled canals were weighed after setting the MTA to calculate difference in mass. Two postoperative radiographs compared radiopacity by measuring luminance variations at 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm from the root apex. Obturation time was measured using a digital chronometer. The significance level was set to p < 0.05. The plugger group had a lower mass. Relative luminance was significantly higher for the Lawaty group than the plugger group at all examined apical levels. The relative luminance of the auger and GP groups were significantly higher than the plugger group at depths between 0.5 mm and 2 mm. Relative luminance was highest for the Lawaty technique at all depths between 0.5 mm and 4 mm. The Lawaty technique group was associated with increased obturation time compared with pluggers. Compacting MTA in curved canals with the Lawaty technique has the highest mass and radiopacity but requires more time.

The Apical Extent of Mineral Trioxide Aggregate Apical Barrier Does not Influence the Treatment Outcome in a Nonvital Immature Permanent Anterior Tooth: A Split-Mouth Clinical Study

Objective:

The study aimed to compare treatment outcomes when MTA apical plugs are placed to different apical extents in nonvital immature permanent anterior teeth with an open apex.

Methods:

Six participants (five male & one female) between the age group of 8-18 years exhibiting bilateral traumatized nonvital immature permanent maxillary anterior teeth (n=12) with non-blunderbuss canal (Cvek’s stage 4) were included. Standardized endodontic procedures were performed, and an inter-appointment calcium hydroxide medicament placed for one week. Based on the apical position of the MTA apical barrier, two study groups were defined. Accordingly, Group I {(n=6) (4mm MTA plug up to the radiographic root end)} and Group II {(n=6) (4 mm MTA plug 2 mm short of the radiographic root-end)}. Teeth were obturated after twenty-four hours with thermoplasticized gutta-percha technique. They were evaluated clinically and radiographically at 12 and 24 months. Radiographs were assessed for periapical healing based on the periapical index (PAI) scores that were dichotomized as score <3 as healed and ≥3 as not healed. The data were compared using Mann Whitney U test, Kruskal Wallis and post hoc analysis.

Results:

At 24 months, all teeth in Group I and II were healed clinically and radiographically. On inter-group comparison, radiographically, all teeth (n=12) exhibited a PAI score <3 and were categorized as healed (P=1.00).

Conclusion:

The apical extent of MTA plug does not influence the treatment outcome. The clinician can place MTA apical plug either up to or 2 mm short of the radiographic root-end.

Treatment of immature teeth with nonvital pulps in adults: a prospective comparative clinical study comparing MTA with Ca(OH)2

AIM

To evaluate and compare the influence of various predictors on outcomes of apexification using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) in permanent immature anterior teeth with necrotic pulps and periapical lesions of adults.

METHODOLOGY

Ninety immature teeth with necrotic pulps and periapical lesions on adult patients (aged 18-40 years) were treated with MTA (45 teeth) or CH (45 teeth) between 2015 and 2018. Patients of both groups were recalled for follow-up examinations after the first intervention at 1,3,6 and 12 months for the first year, every 6 months for the second year and every year thereafter until the end of the study (median 32.3 months). The treatment outcome based on clinical and radiographic criteria was assessed by calibrated examiners and dichotomized as 'healed+healing' or 'not healed'. The age, gender, stage of root development, preoperative signs and symptoms of apical periodontitis and size of periapical lesion were recorded. The cumulative success proportion and mean time were analysed with the Kaplan-Meier test. The generalized logrank statistic was used to describe prognostic clinical variables. Fisher's exact test was applied for the evaluation of the healing rates.

RESULTS

Thirty-nine of the 45 teeth treated with MTA were available for recall. Of these, 29 teeth (74%) revealed calcific apical barrier formation with complete resolution of periapical lesions, 7 teeth (18%) were healing, and 3 teeth (8%) had persistent disease. Thirty-four of the 45 teeth in the CH group were available for recall. Of these, 27 teeth (79%) had complete healing of periapical lesions and had calcific barrier formation, 4 teeth (12%) were healing, and the remaining 3 teeth (9%) had not healed. The survival rate of teeth treated with MTA was similar to the survival rates observed in teeth treated with CH (90% and 91%, respectively, P > 0.05). The generalized logrank statistic revealed that the cumulative success rate of both materials was not significantly different (P > 0.05). None of the tested predictors had an influence on the treatment outcomes of teeth in both groups (P > 0.05).

CONCLUSIONS

Apexification with both MTA and CH was associated with similar treatment outcomes. MTA may be proposed as a material for apexification treatment in immature teeth of adult patients due to the shorter treatment time associated with its use.

In vitro comparison of apical microleakage by spectrophotometry in simulated apexification using White Mineral Trioxide Aggregate, TotalFill Bioceramic Root Repair material, and BioDentine

Aim

The purpose of this study was to compare the sealing ability of various calcium silicate-based root-filling materials with a glucose leakage model after orthograde obturation using an open apex model.

Materials and Methods

Thirty-two recently extracted human maxillary anterior teeth with single, straight root canals were selected and divided into four groups: Group 1 (G1), White Mineral Trioxide Aggregate; the material was delivered into the canal using the MAP system and further compacted with a specific plugger. Group 2 (G2), TotalFill bioceramic Root Repair material: the material was injected directly into the middle half of the root canal. Group 3 (G3), BioDentine; the material was delivered into the canal using the Hawe composite gun and prefitted pluggers.

Statistical Analysis

Statistical analysis was performed using the SPSS 23.0 statistical software package. The Kruskal-Wallis nonparametric test was applied to compare the differences in glucose microleakage.

Results

There were no significant differences among the three experimental groups. The results showed a tendency for leakage to increase from the 1^st day to the end of experimental period.

Conclusions

Within the parameters of this in vitro study, it may be concluded that the three materials evaluated present similar apical microleakage when treating teeth with open apices requiring orthograde delivery of an apical barrier.

Bacterial leakage and marginal adaptation of various bioceramics as apical plug in open apex model

AIM

The aim of the present study was to investigate bacterial leakage and marginal adaptation of bioceramic apical plugs.

METHODS

Extracted human mandibular premolars were prepared to simulate open apex using No. 4 Peeso reamer in retrograde direction. In total, 150 specimens were divided into 10 groups by obturation with five bioceramics in two thicknesses. Groups 1, 3, 5, 7, and 9 were obturated with ProRootMTA, Biodentine, TotalFill BC RRM paste, TotalFill BC RRM putty, and RetroMTA at 3 mm, and groups 2, 4, 6, 8, and 10 were obturated with the same materials at 4 mm. Ten specimens in each group were evaluated for bacterial leakage of Enterococcus faecalis for 75 days. Five specimens from each group were sectioned to investigate the gap area under scanning electron microscope.

RESULTS

The 3- and 4-mm Biodentine and TotalFill BC RRM putty groups and the 4-mm ProRootMTA group exhibited less bacterial leakage and lower mean percentage of gap area than those of the other groups. TotalFill BC RRM paste showed the highest leakage for both the 3- and 4-mm groups.

CONCLUSION

The 3- and 4-mm Biodentine and TotalFill BC RRM putty groups and the 4-mm ProRootMTA group exhibited the best sealing ability and marginal adaptation of apical plugs.

In Vitro Mechanical Properties of Mineral Trioxide Aggregate in Moist and Dry Intracanal Environments

Introduction:

The purpose of this study was to examine the microhardness and modulus of elasticity (MOE) of White ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK) after setting in moist or dry intracanal conditions.

Methods and Materials:

To simulate root canal system, 14 polyethylen molds with internal diameter of 1 mm and height of 12 mm were used. These molds were filled with 9-mm thick layers of White ProRoot Mineral Trioxide Aggregate (MTA; Dentsply Tulsa Dental, Tulsa, OK). The experimental group (n=7) had a damp cotton pellet with 1.5 mm height and a 1.5 mm layer of resin composite placed on it. In control group (n=7) the whole 3 mm above MTA were filled with resin composite. The specimens were kept in 37^°C and relative humidity of 80% for 4 days in order to simulate physiological conditions. Specimens were longitudinally sectioned and nanoindentation tests were carried out using Berkovich indenter at loading rate of 2 mN/s at 4×5 matrices of indents which were located in the coronal, middle and apical thirds of the specimen’s cross section, to evaluate the microhardness and modulus of elasticity of the specimen to appraise the progression of the setting process. Differences were assessed using nonparametric generalized Friedman rank sum and Wilcoxon Rank-Sum tests.

Results:

Statistical analysis showed that there was a significant difference in microhardness and MOE between control and experimental groups at coronal (P<0.001), middle (P<0.001) and apical (P<0.001) thirds of the simulated rod from simulated apical foramen. Kruskal-Wallis test showed no significant effect of depth on microhardness of material in experimental or control groups.

Conclusion:

Within limitations of this in vitro study, it seems that moist intracanal environment improves setting of MTA in various depths.

Analysis of sealing ability of endodontic cements apical plugs

Background

It is unknown whether the bioactivity of Biodentine characterized by the precipitation of hydroxyapatite and formation of tags into the dentinal tubules improve its sealing ability as an apical plug. Aim: To evaluate the sealing ability provided by Biodentine and mineral trioxide aggregate (MTA) apical plugs, with or without phosphate-buffered saline (PBS) intracanal dressing, using a glucose leakage method.

Material and Methods

The space of the canal of 100 root segments with about 12 mm long was shaped using Gates-Glidden. After created an apical retrograde cavity, the root segments were randomly divided into 4 groups (n = 25): G1 - Biodentine; G2 - Biodentine + PBS intracanal dressing; G3 - MTA and G4 - MTA + PBS intracanal dressing. All access openings were filled with temporary cement and all root segments were introduced in floral foams moistened with PBS. After 2 months, all root segments were prepared to evaluate the glucose leakage. The amount of glucose leakage was quantified by a spectrophotometer and the data were analyzed using chi-square test (p<0.05).

Results

Traces of the glucose were observed in a higher of samples that received Biodentine apical plug (p<0.05). The exposure to intracanal PBS did not influence the sealing provided by Biodentine and MTA.

Conclusions

The Biodentine had lower sealing ability than MTA. The interaction with PBS intracanal dressing did not improve the sealing ability provided by sealers. Key words:Apexification, dental cements, dental leakage, glucose, pressure.

Effect of Propylene Glycol on the Sealing Ability of Mineral Trioxide Aggregate and Calcium-Enriched Mixture Cement Apical Barriers

Introduction:

Propylene glycol (PG) improves the handling, physical, and chemical properties of mineral trioxide aggregate (MTA). This study aimed to evaluate the effect of PG on the sealing ability of MTA and calcium-enriched mixture (CEM) apical barriers.

Methods and Materials:

A total of 70 extracted human maxillary single-rooted teeth were prepared using ProTaper rotary system. The apical 3 mm of the root tips were resected and the root canals were enlarged with Peeso reamers up to #4, to create open apex teeth. The teeth were then randomly divided into four experimental (n=15) and two control (n=5) groups. Group1: MTA+ MTA liquid, group2; MTA+MTA liquid (80%) + PG (20%), group3; CEM+CEM liquid, group4; CEM+ liquid (80%) + PG (20%). Cements were mixed with their respective mixing agents and a 4-mm thick apical plug was fabricated. The microleakage was measured on day 1, 3, 7 and 21 using a fluid filtration technique. The repeated measures ANOVA and Sidak test were used to analyze the data.

Results:

All experimental groups demonstrated various amounts of microleakage. No significant difference was found between MTA and CEM cement (P=0.193), regardless of time and liquid components. There was no significant difference was observed between liquids (P=0.312) in all time intervals. The rate of microleakage decreased over time and a significant differences was observed between all intervals (P<0.05), except 3-7 and 7-21 (P=0.190) days.

Conclusion:

PG demonstrated neither a positive nor a negative effect on the sealing ability of Angelus MTA and CEM cement.

Combined effects of mineral trioxide aggregate and human placental extract on rat pulp tissue and growth, differentiation and angiogenesis in human dental pulp cells

OBJECTIVE

The aim of this study was to evaluate the combined effects of mineral trioxide aggregate (MTA) and human placental extract (HPE) on cell growth, differentiation and in vitro angiogenesis of human dental pulp cells (HDPCs) and to identify underlying signal transduction mechanisms. In vivo dental pulp responses in rats for a pulp-capping agent were examined.

MATERIALS AND METHODS

MTS assay. ALP activity test, alizarin red S staining and RT-PCR for marker genes were carried out to evaluate cell growth and differentiation. HUVEC migration, mRNA expression and capillary tube formation were measured to evaluate angiogenesis. Signal transduction was analysed using Western blotting and confocal microscopy. The pulps of rat maxillary first molars were exposed and capped with either MTA or MTA plus HPE. Histologic observation and scoring were performed.

RESULTS

Compared to treatment of HDPCs with either HPE or MTA alone, the combination of HPE and MTA increased cell growth, ALP activity, mineralized nodules and expression of marker mRNAs. Combination HPE and MTA increased migration, capillary tube formation and angiogenic gene expression compared with MTA alone. Activation of Akt, mammalian target of rapamycin (mTOR), p38, JNK and ERK MAPK, Akt, and NF-κB were significantly increased by combining HPE and MTA compared with MTA alone. Pulp capping with MTA plus HPE in rats showed superior dentin bridge formation, odontoblastic layers and dentinal tubules and lower inflammatory cell response, compared to the MTA alone group.

CONCLUSIONS

This study demonstrates for the first time that the use of MTA with HPE promotes cell growth, differentiation and angiogenesis in HDPCs, which were associated with mTOR, MAPK and NF-κB pathways. Direct pulp capping with HPE plus MTA showed superior results when compared with MTA alone. Thus, the combination of MTA and HPE may be useful for regenerative endodontics.

Efficacy of Biodentine as an Apical Plug in Nonvital Permanent Teeth with Open Apices: An In Vitro Study

The aim of this study was to evaluate the apical microleakage of Biodentine and MTA orthograde apical plugs and to compare the effect of thickness of these biomaterials on their sealing ability. A total of eighty maxillary anterior teeth were used. The apices were removed by cutting with a diamond disc (Jota, Germany) 2 mm from the apical root end in an attempt to standardize the working length of all specimens to 15 ± 1 mm. Both materials were placed in 1–4 mm thickness as apical plugs root canal. Root canal leakage was evaluated by the fluid filtration technique. One-way ANOVA was used in order to determine normality of dispersal distribution of parameters; thereafter, results were analyzed by Kolmogorov-Smirnov test. Overall, between microleakage values of MTA and Biodentine regardless of apical plug thickness, no difference was observed. In terms of plug thickness, a statistically significant difference was observed between the subgroups of MTA and Biodentine (p < 0.05). The apical sealing ability of Biodentine was comparable to MTA at any apical plug thickness.

A Randomized Controlled Study of the Use of ProRoot Mineral Trioxide Aggregate and Endocem as Direct Pulp Capping Materials: 3-month versus 1-year Outcomes

INTRODUCTION

The purpose of this study was to assess the long-term clinical outcomes of direct pulp capping (DPC) with ProRoot MTA (Dentsply, Tulsa, OK) and Endocem (Maruchi, Wonju, Korea) as pulp capping materials. To this end, the 1-year cumulative successes of both materials were evaluated and compared with those of the 3-month outcomes in a prospective, randomized controlled trial.

METHODS

Patients were recruited from the Department of Conservative Dentistry of the Yonsei University Dental Hospital, Seoul, South Korea, from January to May 2013. Of the 48 teeth that met the inclusion criteria, 46 teeth were randomly allocated to either ProRoot MTA or Endocem groups (n = 23). Direct pulp capping was performed, and clinical and radiographic examinations were conducted over 1 year after the treatment. Survival analyses were conducted to compare the cumulative successes between ProRoot MTA and Endocem and to evaluate other clinical variables.

RESULTS

Forty-one teeth were recalled 1 year after the treatments (recall rate = 89.13%). There were no significant differences between the cumulative successes of ProRoot MTA and Endocem in either log-rank or Cox proportional hazard regression analyses (P > .05). Among the other clinical variables, cavity type (class I, II, III vs class V) was determined to be significant in both the log-rank test (P = .001) and Cox regression analysis (P = .006).

CONCLUSIONS

Both ProRoot MTA and Endocem exhibited similar cumulative successes as direct pulp capping materials up to 1 year. The teeth restored with class V cavities exhibited significantly lower cumulative success rates after direct pulp capping compared with the teeth restored with other types of cavities.

Comparing the Coronal Seal of Different Thicknesses of MTA with Gutta-Percha after Post Space Preparation

INTRODUCTION

The aim of this study was to compare the coronal seal of different thicknesses of MTA with gutta-percha after post space preparation.

MATERIALS AND METHODS

A total of 50 maxillary central incisors randomly divided into 5 experimental groups (n = 8). After preparation of the root canals with step back technique, in groups 1 and 2, post spaces were prepared and 4 or 5 mm gutta-percha remained in the apical, respectively. In groups 3, 4, and 5, there was 1-2 and 3 mm MTA in the apical, respectively. The ten teeth serve as control groups. The teeth were connected to a bacterial microleakage evaluation system. The study period was 120 days and the samples were evaluated on ten-day intervals; Meier-Kaplan technique was used for estimation of the mean time of microleakage to occur. Log-rank test was used for comparison of microleakage.

RESULTS

Number of samples exhibiting microleakage in MTA was less than those of gutta-percha at all intervals. Means of days with no microleakage were maximum and minimum with 3 mm MTA and 4 mm gutta-percha, respectively.

CONCLUSION

Obturation of root canals using the MTA technique provides a proper seal with the minimum thickness of MTA in teeth requiring post space preparation.

Marginal adaptation of mineral trioxide aggregate (MTA) to root dentin surface with orthograde/retrograde application techniques: A microcomputed tomographic analysis

Background:

Achieving a good apical seal for root canals is known to be associated with good mineral trioxide aggregate (MTA) adaptation to dentin.

Aims:

This study aims to compare the marginal adaptation of MTA with root dentin between orthograde and retrograde application techniques using microcomputed tomography (micro-CT) analysis.

Settings and Design:

Fifty-two single-rooted human teeth were divided into four equal groups: (Group 1) Retrograde MTA (RMTA), (Group 2) Orthograde MTA (OMTA), (Group 3) Etched RMTA (ERMTA), and (Group 4) Etched OMTA (EOMTA).

Materials and Methods:

For Group 1, 3-mm retrograde cavities were prepared and filled with MTA. For Group 2, the apical 6 mm of the canals were filled with MTA and sealed with sealer cement and warm gutta-percha. In Groups 3 and 4, canals were treated the same as Groups 1 and 2, respectively, except that before placing the MTA, canals were irrigated with 17% ethylenediaminetetraacetic acid (EDTA). After 48 hours, all the teeth were analyzed using a micro-CT scanner.

Statistical Analysis:

Mean dentin-MTA contact and the mean length and width of each gap was analysed using one-way analysis of variance (ANOVA). Statistical significance was set at an α level of 5%.

Results:

No significant difference in gap volumes was observed in the dentin-MTA adaptation in both orthograde and retrograde application techniques. However, significant difference in the gap volumes was observed between RMTA and ERMTA (P = 0.045). Etching significantly improved the MTA-Dentin adaptation (P < 0.05). The type of application technique did not significantly improve the dentin-MTA adaptation, instead with the use of 17% EDTA, a significant improvement could be achieved.

Conclusion:

Within the limitations of the present study, it concludes that MTA adaptation to dentin tooth structure is not significantly different between an orthograde and retrograde approach. However, the use of EDTA significantly improved the MTA-Dentin adaptation.

Resistance to leakage of various thicknesses of apical plugs of Bioaggregate using liquid filtration model

AIM

The aim of this study was to compare the resistance to leakage of different thicknesses of Bioaggregate (BA) and 4-mm-thick white mineral trioxide aggregate (WMTA) in an apexification model using liquid filtration.

METHODS

32 extracted mandibular premolar teeth were sectioned at the cemento-enamel junction and 3-4 mm from the tooth apex to obtain 12-mm-long root segments. The apical and coronal thirds were prepared with size two through six Gates Glidden burs. The teeth were divided into four groups according to material and thickness, as follows: Group 1: 2-mm BA; Group 2: 4-mm BA; Group 3: 12-mm (total length) BA; Group 4: 4-mm WMTA (control). The empty parts of the roots in Groups 1, 2, and 4 were filled with gutta-percha and root canal sealer, and leakage was measured using fluid filtration. The data were analyzed using the Kruskal-Wallis H-test.

RESULTS

No statistical differences in microleakage were observed between Groups 1, 2, and 4 (P > 0.05). Group 3 (roots filled completely with BA) showed significantly less leakage than the other groups tested (P < 0.01).

CONCLUSIONS

The findings of this study showed that 12 mm of BA exhibited the best resistance to leakage. At the same time, 2-4 mm of BA showed similar results when compared to 4-mm MTA. In light of these results, this study suggests that BA may be a good candidate for further clinical studies when used as an apical barrier for apexification.

Mineral trioxide aggregate as apical plug in teeth with necrotic pulp and immature apices: a 10-year case series

INTRODUCTION

This 10-year study evaluated the clinical and radiologic outcomes of teeth with necrotic pulp, immature apices, and periapical lesions treated with the mineral trioxide aggregate (MTA) apical plug technique.

METHODS

Seventeen single-rooted immature teeth with necrotic pulp and periapical lesion from 17 patients treated between January 2001 and December 2001 were included in this study. Apical obturation on all teeth included in the study was completed in 2 visits: first using calcium hydroxide as an interappointment intracanal medication and a second visit for the creation of the artificial apical barrier with MTA. The outcome, based on clinical and radiographic criteria, was assessed by 2 calibrated investigators using the periapical index (PAI). The Friedman test was used to verify the differences between baseline and the 1-, 5-, and 10-year PAI scores.

RESULTS

Of the 17 patients treated, 1 patient dropped out at 5 years. At the 10-year follow-up, 15 teeth were healed (PAI ≤2), and 1 tooth had been extracted because of the presence of a longitudinal root fracture. The PAI score exhibited a significant decrease between baseline and 1 year and between 1 and 5 years. The difference between 5 and 10 years was not significant.

CONCLUSIONS

The apical plug with MTA was a successful and effective technique for long-term management of this group of teeth with necrotic pulps with immature root development and periapical lesions.

Root Reconstructed with Mineral Trioxide Aggregate and Guided Tissue Regeneration in Apical Surgery: A 5-year Follow-up

Apical surgery should be considered as the last treatment option and employed when conventional endodontic treatment does not provide the expected result. In teeth undergoing apical surgery, the type of retrograde filling material is one of the factors interfering with the repair of periapical tissues. The material in intimate contact with the periapical tissues plays a fundamental role in the repair process. Several materials have been studied and indicated for use in apical surgery procedures, but the mineral trioxide aggregate (MTA) is still the most frequently used one. Guided tissue regeneration (GTR) techniques have been proposed as an adjunct to apical surgery to enhance bone healing. Here is reported a clinical case in which apical surgery was performed in conjunction with MTA-based root reconstruction of the maxillary right second incisor. After the apical surgery, a root-end cavity was prepared at the vestibular face of the involved tooth and filled with MTA. A bovine bone graft and a cortical collagen membrane were placed on the bone defect. After 5 years, clinical and radiographic assessments showed that the treatment was successful. It may be concluded that MTA presents favorable characteristics in adverse conditions and can be used in conjunction with GTR in cases involving root reconstruction.

Evaluation of Apical Microleakage in Open Apex Teeth Using MTA Apical Plug in Different Sessions

Aim. To compare microleakage of apexification using MTA in one or two sessions. Materials and Methods. 88 single rooted teeth were prepared and divided into two groups then received MTA apical plug. In the first group, the teeth were immersed in normal saline for 24 hours and then backfilled with guttapercha and AH26 sealer. In the second group, the teeth were obturated immediately after receiving apical plug. Four positive and four negative controls were selected. All specimens were placed in 1% methylene blue and decalcified in 5% nitric acid and finally were placed in methyl salicylate until getting transparent. All teeth were visualized for assessment of dye penetration under stereo dissecting microscope. Results. 36 and 35 teeth showed dye leakage in the first and second groups. Dye penetration into the entire canal length was confirmed in the positive control group, and in the negative control group no dye penetration was seen. Mean dye penetration in the first and second group was 5813 and 9152  μ m. t-test revealed a significant difference between dye penetrations of two groups (P < 0.05). Conclusion. MTA requires adequate time for setting in the presence of the moisture, and final obturation should be delayed until final setting of MTA.

Comparison of endodontic biomaterials as apical barriers in simulated open apices

Objectives. To evaluate the effect of apical foramen diameter and apical barrier thickness on the sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs in open apices. Materials and Methods. The fluid filtration method was conducted on a total of 136 roots. Samples were randomly divided into two control (n = 8) and four experimental groups (n = 30). Apical foramen diameters measuring 1.1 and 1.7 mm were shaped for groups "1 and 3" and "2 and 4", respectively. In groups 1 and 2 MTA plug and in groups 3 and 4 CEM plug was inserted. The groups were further divided into subgroups according to the thickness of the apical plugs (3- or 5-mm). Microleakage was measured at 1, 7, and 30 days. Results. Mixed ANOVA test showed that the microleakage in groups 1 and 3 as well as all 5-mm plug subgroups were significantly less than groups 2 and 4 (P < 0.05) and 3-mm subgroups (P < 0.05), respectively. Microleakage was significantly lower at 30th day (P < 0.05). Conclusions. Reducing canal diameter or increasing apical plug thickness and the time interval increases the sealing ability of apical barriers. Furthermore, in comparison to MTA, CEM plugs demonstrated superior sealing ability.

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

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

Mineral trioxyde aggregate versus calcium hydroxide in apexification of non vital immature teeth: study protocol for a randomized controlled trial

Background

Pulp necrosis is one of the main complications of dental trauma. When it happens on an immature tooth, pulp necrosis implies a lack of root maturation and apical closure. A therapy called apexification is required to induce the formation of a calcified apical barrier allowing a permanent and hermetic root filling. The aim of this prospective randomized clinical trial is to compare Mineral Trioxide Aggregate(MTA)with Calcium Hydroxide(CH)as materials used to induce root-end closure in necrotic permanent immature incisors.

Methods/Design

This study, promoted by AP-HP, was approved by the ethics committee(CPP Paris Ile de France IV). 34 children aged from 6 to 18 years and presenting a non-vital permanent incisor are selected. Prior to treatment, an appropriate written consent has to be obtained from both parents and from children. Patients are then randomly assigned to either the MTA(experimental)or CH(control)groups. Recalls are performed after 3, 6 and 12 months to determine the presence or absence of a calcified apical barrier through the use of clinical and radiographic exams. Additional criteria such as clinical symptoms, apical radiolucencies, periapical index(PAI)are also noted.

Trial registration

ClinicalTrials.gov no. NCT00472173 (First inclusion: May 10, 2007; Last inclusion: April 23, 2009; study completed: April 15, 2010)

Strategies to manage permanent non-vital teeth with open apices: a clinical update

If dental pulp injury occurs prior to complete root formation and apical closure, normal root development is halted. This condition produces several complications. Firstly, the apical diameter of the canal is often larger than the coronal diameter, so debridement is difficult. Secondly, the lack of an apical stop makes the obturation in all dimensions virtually impossible. And finally, the thin walls of the root canal are prone to fracture, so that surgical treatment is generally not a viable option. There are a number protocols to manage non-vital open-apex teeth such as apexification, apical barrier technique (one-visit apexification), orthograde root filling using MTA, triple antibiotic paste, and tissue engineering concept. The aim of this paper is to review these treatment protocols.

Evaluation of alveolar socket response to Angelus MTA and experimental light-cure MTA

OBJECTIVE

The aim of this study was to evaluate the rat alveolar socket response to implanted polyethylene tubes filled with a light-cured MTA or Angelus MTA.

STUDY DESIGN

Fifty-seven Wistar rats received an implant filled with one of the materials in the dental socket of the right central incisor. After 30, 60, and 90 days, animals were killed, and the right hemimaxillas were removed and processed to be analyzed on light microscopy. After embedding in paraffin, 6-μm-thick sections were obtained and stained with hematoxylin and eosin. Qualitative and quantitative analyses of the reaction were performed.

RESULTS

It was observed that the light-cured MTA presented a similar response compared with Angelus MTA, characterized by the reduction of the chronic inflammatory response and organization of the alveolar bone close to the materials, especially at the 90th day of observation.

CONCLUSIONS

It was concluded that both materials were well accepted by the alveolar tissue of rats, with the formation of mineralized tissue close to the materials.

Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs

Objective

This study used dye leakage assay and scanning electron microscopy to evaluate, respectively, the sealing ability and marginal adaptation of three root-end filling materials used as apical plugs, as well as the possible correlation between these properties.

Material and Methods

Ninety-eight single-rooted human teeth were prepared to simulate an open apex. The teeth were allocated to three experimental groups (n = 30), which received a 5-mm thick apical plug of (1) gray MTA Angelus^TM, (2) CPM^TM and (3) MBPc, and two controls groups (n = 4). After immersion in 0.2% Rhodamine B solution for 48 h, the teeth were sectioned longitudinally and analyzed by Image Tool 3.0 software. The marginal adaptation between apical plugs and the root canal walls were analyzed by SEM.

Results

MBPc had significantly less (p<0.05) apical leakage than the other materials. Regarding marginal adaptation, CPM^TM showed the best numerical results, though without statistical significance from the other materials (p<0.05). There was no correlation between the two properties.

Conclusions

When used as apical plugs, the tested root-end filling materials had similar marginal adaptation to the dentin walls, but MBPc had the best sealing ability, as demonstrated by the least apical leakage from all tested materials.

In vitro sealing ability of white and gray mineral trioxide aggregate (MTA) and white Portland cement used as apical plugs

This study evaluated the sealing ability of apical plugs made of white and gray MTA-Angelus and white Portland cement placed via the root canal and having different thicknesses (2, 5 and 7 mm). Ninety extracted human single-rooted teeth were instrumented using a size 40 K-file to standardize the foraminal opening by the stepback technique. The teeth were assigned to 3 groups (n=30), according to the material used for fabrication of the apical plugs: A = gray MTA; B = white MTA; C = white Portland cement. The groups were subdivided into groups of 10 teeth each according to the apical plug thickness (2, 5 and 7 mm). Marginal apical dye leakage was assessed using 0.2% Rhodamine B solution in which the specimens were immersed for 72 hours at 37 degrees C. The roots were sectioned longitudinally in a buccolingual direction for apical plug exposure, and digital photographs were taken and analyzed by Image Tool image-analysis software. Data were analyzed statistically by Kruskal-Wallis and Dunn's tests. Significance level was set at 5%. The least percent leakage was observed for 5- and 7-mm-thick plugs (p<0.05). No significant difference (p>0.05) was found between gray MTA and white Portland cement. Among the three materials analyzed, white MTA presented the highest marginal leakage (p<0.05). The findings of the present study showed that gray MTA and Portland cement had better sealing ability than white MTA when used as apical plugs. Dye leakage was smaller for 5- and 7-mm-thick plugs compared to 2-mm-thick plugs.