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.

Nonsurgical management of type II dens invaginatus with cone beam computed tomography: A rare case.

Dens invaginatus is a progressive abnormality resulting from invagination of the crown or root before calcification. This case report presents nonsurgical endodontic treatment and nine-year follow-up results of a right maxillary canine tooth with type II dens invaginatus. A 40-year-old female patient was referred to the clinic for treatment of her maxillary right canine tooth. The invagination was managed on a two-visit appointment. On the first visit, the invagination area, which was disconnected, was completely removed from the root canal. The invagination area was instrumented, and the root canal was dressed with calcium hydroxide. At the second appointment, apexification was done using mineral trioxide aggregate compacted to the apical 3mm. Finally, the invaginated area and the root canal were obturated with a warm vertical compaction technique. At a nine-year follow-up, the invaginated tooth was asymptomatic, and the periradicular lesion showed satisfactory healing radiographically.

Efficacy of Mineral Trioxide Aggregate Repair High Plasticity, Biodentine, and EndoSequence Root Repair Material Putty as Apical Barriers in Immature Permanent Teeth: An In Vitro Bacterial Leakage Study.

AIM: To assess the microleakage of mineral trioxide aggregate (MTA) repair high plasticity (HP), EndoSequence root repair material (ESRRM) putty, and Biodentine, when used as an apical plug in immature permanent teeth. MATERIALS AND METHODS: In an in vitro model, 55 extracted maxillary incisors were decoronated and resected 3 mm apically to obtain standardized 15-mm root blocks, which were then cleaned and shaped. All samples had a 1.1-mm standardized, prepared artificial open apex. The teeth were arbitrarily designated into three experimental groups (n = 15) and two control (positive/negative) groups (n = 5). In the experimental groups, orthograde 4-mm thick apical plugs of Biodentine (group I), ESRRM putty (group II), and MTA repair HP (group III) were placed. Positive control samples were left vacant while negative control samples were filled with Biodentine. The bacterial leakage method was used to appraise the sealing efficiency of the cements. RESULTS: Statistical package for the social sciences (SPSS) software, version 21.0, was used for data analysis. Post hoc Tukey's test, one-way analysis of variance (ANOVA), and repeated measures of ANOVA were used for intergroup and intragroup comparisons. On day 1, there was a significant difference between the groups, with group II showing the least and group 1 showing the maximum microleakage. No significant difference among the groups was seen at other observational periods. There was a tendency for leakage to increase significantly from day 1 to 7, then decrease till the end of the experimental period. CONCLUSION: It was concluded that the three materials evaluated, with time, exhibited comparable apical microleakage when treating teeth with open apices. CLINICAL SIGNIFICANCE: MTA repair HP can be used as an apical plug material in open apices with similar success as ESRRM putty and marginally better outcome than Biodentine.

Effectiveness of MTA apical plug in dens evaginatus with open apices.

BACKGROUND: The present study aims to evaluate the effectiveness of mineral trioxide aggregate (MTA) application in treating dens evaginatus affected teeth with apical lesions and open apices using haemostatic collagen membrane to prevent the apical extrusion of MTA. METHODS: Twelve patients with 14 dens evaginatus affected teeth with apical lesions and open apices were treated with MTA apical plug and haemostatic collagen membrane. Clinical symptoms of subjective pain, pain of palpation, percussion, sinus tract, and the apical lesions' radiographic parameter were recorded at every 3-month interval up to 9 months after treatment. Paired t-test or Wilcoxon signed-rank test was used for statistical analysis with P < 0.05 as the threshold for considering results to be statistically significant. RESULTS: No patient experienced clinical symptoms 3 months after endodontic treatment. In addition, there was a significant difference in the dimensions of the apical lesions' before compared to 3 months after endodontic treatment. CONCLUSIONS: The combination of MTA apical plug and haemostatic collagen membrane effectively treated dens evaginatus affected teeth with apical lesions, and open apices.

Use of Mineral Trioxide Aggregate with or without a Collagen Sponge as an Apical Plug in Teeth with Immature Apices.

OBJECTIVE: This retrospective study aimed to evaluate the clinical outcomes of the apical plug performed using MTA with or without collagen sponge in immature anterior maxillary teeth with necrotic pulp. STUDY DESIGN: The study included apical obturation of 20 upper incisor teeth from 18 patients and outcomes of 12-month follow-up. The teeth were divided into 2 groups with 10 cases in each group according to the apexification protocol (Group 1; apical plug with MTA, Group 2; collagen sponge and apical plug with MTA). The artificial apical barrier, approximately 4-mm-thick, was created with MTA in each group. Based on clinical and radiographic criteria, the outcome was assessed using the periapical index (PAI) by 2 calibrated investigators. RESULTS: In this study, 3 of the 6 teeth (50%) in Group 1 and 5 of the 8 teeth (62.5%) in Group 2 healed at the 12-month follow-up. However, there was no statistically significant difference between the groups at the post-treatment follow-up times. CONCLUSION: The use of collagen as an apical matrix prior to the MTA plug can be suggested due to favorable clinical outcomes.

Mineral trioxide aggregate and other bioactive endodontic cements: an updated overview - part II: other clinical applications and complications.

Mineral trioxide aggregate (MTA) is a dental material used extensively for vital pulp therapies (VPT), protecting scaffolds during regenerative endodontic procedures, apical barriers in teeth with necrotic pulps and open apices, perforation repairs as well as root canal filling and root-end filling during surgical endodontics. A number of bioactive endodontic cements (BECs) have recently been introduced to the market. Most of these materials have calcium and silicate in their compositions; however, bioactivity is a common property of these cements. These materials include the following: BioAggregate, Biodentine, BioRoot RCS, calcium-enriched mixture cement, Endo-CPM, Endocem, EndoSequence, EndoBinder, EndoSeal MTA, iRoot, MicroMega MTA, MTA Bio, MTA Fillapex, MTA Plus, Neo MTA Plus, Ortho MTA, Quick-Set, Retro MTA, Tech Biosealer, and TheraCal LC. It has been claimed that these materials have properties similar to those of MTA but without the drawbacks. In Part I of this review, the available information on the chemical composition of the materials listed above was reviewed and their applications for VPT was discussed. In this article, the clinical applications of MTA and other BECs will be reviewed for apexification, regenerative endodontics, perforation repair, root canal filling, root-end filling, restorative procedures, periodontal defects and treatment of vertical and horizontal root fractures. In addition, the literature regarding the possible drawbacks of these materials following their clinical applications is reviewed. These drawbacks include their discolouration potential, systemic effects and retreatability following use as a root filling material. Based on selected keywords, all publications were searched regarding the use of MTA as well as BECs for the relevant clinical applications. Numerous publications were found regarding the use of BECs for various endodontic applications. The majority of these investigations compared BECs with MTA. Despite promising results for some materials, the number of publications using BECs for various clinical applications was limited. Furthermore, most studies had several methodological shortcomings and low levels of evidence.

Comparison of fracture resistance of simulated immature teeth using four different commercially available apexification materials - An in vitro study.

Introduction: The aim of this study was to compare the fracture resistance of simulated immature teeth using four different apical plug materials, i.e. Pro- Root MTA, Neo- MTA Plus, Biodentine, and Bioactive Glass. Materials and Methods: 80 extracted human maxillary anterior teeth were divided into 4 groups for this study. They were prepared using Peeso reamers to simulate immature teeth and to mimic Cvek's stage 3 of root development. A 5 mm apical barrier was placed using different materials. The remaining canal was obturated using gutta-percha and AH plus sealer. The final samples were stored at 37°C and 100% humidity for 4 weeks. Fracture resistance of the teeth was measured in Newtons using a universal testing machine. The comparison of fracture resistance between the four groups was done using Kruskal Walis ANOVA followed by post hoc Mann Whitney U test for pairwise comparison. Results: Biodentine group showed the highest fracture resistance as compared to the other three groups and the difference was highly significant (P < 0.001). Conclusions: Biodentine can be advocated over MTA as an effective material for the management of teeth with wide open apex. Bioactive glass also has shown promising results in increasing the fracture resistance of simulated immature teeth.

Simplified Orthograde Apical Plug and Intra-Orifice Barriers for Resolving a Complex Endodontic Challenge: A Case Report.

Successful endodontic treatments are contingent upon establishing a hermetic seal within the root canal system. This seal is pivotal in preventing/resolving apical periodontitis. This case report introduces a simplified orthograde apical plug and intra-orifice barrier technique as an effective alternative to previously unsuccessful invasive nonsurgical and surgical treatments. A 28-year-old patient presented with persistent discomfort and localized swelling in the furcation area of the mandibular left first molar. The tooth had previously undergone both root canal therapy and surgical retreatment. A distinctive feature of this case was the unconventional amputation of the mesial root, unlike conventional periradicular surgery or root amputation. This unusual scenario was accompanied by the presence of a large endodontic lesion. An apical plug, utilizing calcium-enriched mixture (CEM) cement, was placed, complemented by the use of CEM intra-orifice barriers to ensure the hermetic sealing of the entire root canal system. Long-term follow-up assessment demonstrated the complete healing of the preexisting large endodontic lesion. This case underscores the significance of proper diagnosis, right treatment planning, and considering conservative treatment options for complex cases, highlighting the pivotal role played by a reliable seal in achieving successful results in endodontic procedures.

Comparative evaluation of mineral trioxide aggregate and biodentine apical plug thickness on fracture resistance of immature teeth: An In vitro study.

Aim: This study aims to compare the fracture resistance of simulated immature teeth after using different thicknesses of Mineral Trioxide Aggregate (MTA) and Biodentine apical plug. Materials and Methods: Forty human maxillary anterior teeth were selected. Teeth were randomly divided into eight groups of five teeth in each group. Positive control group = 5 teeth; prepared without access cavity preparation. Access cavities of the remaining 35 teeth were prepared, and instrumented with Peeso reamers. Negative control = 5 teeth; filled with calcium hydroxide. Thirty teeth divided into Groups 1 and 2 of MTA (MTA-Angelus, Londrina, Brazil) and Biodentine (Septodant, Saint Maur des Fosses, France) and each group divided into three subgroups: subgroup A - 3 mm apical plug; subgroup B - 6 mm apical plug; and subgroup C: full canal length. The rest of the canals in subgroups A and B were filled with gutta-percha and AH Plus sealer. After the required storage period, all the samples were subjected to fracture testing under universal testing machine and fracture strength was recorded. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons. Results: The negative control group showed the lowest fracture resistance compared with the other groups (P < 0.0001). The 6-mm apical plug subgroup of biodentine showed the highest fracture resistance. Conclusion: Within the limitations of this study, MTA and Biodentine can be used as an apical plug instead of root canal filling material to increase the fracture resistance of immature teeth.

Résumé Objectif: Cette étude vise à comparer la résistance à la fracture de dents immatures simulées après utilisation de différentes épaisseurs de trioxyde minéral Agrégat (MTA) et bouchon apical Biodentine. Matériel et Méthodes: Quarante dents antérieures maxillaires humaines ont été sélectionnées. Les dents étaient divisé au hasard en huit groupes de cinq dents dans chaque groupe. Groupe témoin positif = 5 dents; préparé sans préparation de la cavité d'accès. Les cavités d'accès des 35 dents restantes ont été préparées et instrumentées avec des alésoirs Peeso. Contrôle négatif = 5 dents; rempli de calcium hydroxyde. Trente dents réparties en groupes 1 et 2 de MTA (MTA-Angelus, Londrina, Brésil) et Biodentine (Septodant, Saint Maur des Fosses, France) et chaque groupe divisé en trois sous-groupes: sous-groupe A - bouchon apical de 3 mm; sous-groupe B - bouchon apical de 6 mm; et sous-groupe C: longueur totale du canal. Les autres canaux des sous-groupes A et B étaient remplis de gutta-percha et de scellant AH Plus. Après le stockage requis période, tous les échantillons ont été soumis à des essais de fracture sous une machine d'essai universelle et la résistance à la rupture a été enregistrée. Les données étaient analysé à l'aide d'une analyse de variance unidirectionnelle avec le test post hoc de Tukey pour des comparaisons multiples. Résultats: le groupe témoin négatif a montré la résistance à la fracture la plus faible par rapport aux autres groupes (p <0,0001). Le sous-groupe du bouchon apical de 6 mm de la biodentine a montré le plus résistance à la fracture. Conclusion: Dans les limites de cette étude, le MTA et la Biodentine peuvent être utilisés comme bouchon apical au lieu de canal radiculaire matériau de remplissage pour augmenter la résistance à la fracture des dents immatures. Mots-clés: bouchon apical, biodentine, résistance à la fracture, agrégat de trioxyde minéral.

Evaluation of a Novel Tool for Apical Plug Formation during Apexification of Immature Teeth.

The purpose of this study was to compare the sealing ability and time required for the formation of Biodentine and mineral trioxide aggregation (MTA) apical plugs, using three different delivery methods: an amalgam carrier (AC), the Micro Apical Placement (MAP) System or a novel tool using a modified cannula (MC). Materials and Methods: A total of 60 uniformed molar roots were divided into three main groups, according to the technique of apical plug formation: AC, MAP, and MC. Each group was divided into two subgroups, according to the filling material used: MTA and Biodentine. A timer was used to calculate the required time for apical plug formation. After setting the filling materials, the apical microleakage of the formed plugs was quantified using the dye extraction method and spectrophotometry. The differences between the groups were analyzed using the one-way ANOVA and LSD post hoc tests. The significance level was set at 0.05. Results: No significant differences were reported in the time required to form the apical plugs in all groups (p > 0.05). However, the apical plugs formed by the AC method had significantly higher microleakage than those formed using the MAP and MC methods (p < 0.05). Conclusion: Within the limitations of this study, the sealing ability of the apical plugs formed by the MC method is comparable to the MAP method and better than the AC method.

The Effect of Ultrasonic Agitation on the Porosity Distribution in Apically Perforated Root Canals Filled with Different Bioceramic Materials and Techniques: A Micro-CT Assessment.

The present study evaluated the effect of ultrasonic agitation on the porosity distribution of BioRoot RCS/single gutta-percha cone (BR/SC) and MTA Flow (MF) root canals fillings used as apical plugs in moderately curved and apically perforated roots. Eighty mesial root canals of mandibular first molars were enlarged up to ProTaper NEXT X5 rotary instrument 2 mm beyond the apical foramen, simulating apical perforations. Specimens were randomly divided into four experimental groups (20 canals per group) according to the material and technique used for root canal obturation: BR/SC, BR/SC with ultrasonic agitation (BR/SC-UA), MF and MF with ultrasonic agitation (MF-UA). The ultrasonic tip was passively inserted into the root canal after the injection of flowable cement and activated for 10 s. The specimens were scanned before and after obturation with a high-resolution micro-computed tomography scanner, and the porosity of the apical plugs was assessed. The differences between groups were analyzed using the Kruskal-Wallis and Mann-Whitney tests, with the significance level set at 5%. None of the obturation materials and techniques used in this study was able to provide a pore-free root canal filling in the apical 5 mm. Considerably higher percentages of open and closed pores were observed in the MF and MF-UA groups, with the highest porosity being in the MF-UA group (p < 0.05). No significant differences were observed between the BR/SC and BR/SC-UA groups, where the quantity of open and closed pores remained similar (p > 0.05).

Effect of the Periapical "Inflammatory Plug" on Dental Pulp Regeneration: A Histologic In Vivo Study.

INTRODUCTION: In the current study, we investigate the effect of the inflammation occupying the apical foramen-a phenomenon we refer to as "inflammatory plug"-on the regenerative potential of a root canal therapy. METHODS: We performed root canal treatment (RCT) in 12 canine root canals while aseptically instrumenting the apex to a 0.5-mm-wide foramen and obturating the canals with the following materials: collagen sponge, platelet-rich fibrin, and blood clot (no material introduced). RESULTS: We were successful in maintaining the integrity of the periapical tissue in 8 of 12 RCTs. Injury to the periapical tissue occurred during the remaining 4 RCTs, which initiated inflammation accompanied by bone and dentin resorption. Our histologic analyses showed that the resulting inflammatory plug contained abundant M1 macrophages and was associated with an absence of intracanal cellular infiltration. On the contrary, noninflamed samples showed signs of repair, as indicated by the migration of periapical cells throughout the root canal. CONCLUSIONS: We conclude that controlling periapical inflammation is key while attempting to achieve dental pulp regeneration.

Finite element analysis of immature teeth filled with MTA, Biodentine and Bioaggregate.

BACKGROUND AND OBJECTIVE: Finite element based simulation has emerged as a powerful tool to analyse the tooth strength and its fracture characteristics. The aim of this study is to compare and evaluate the fracture resistance of immature teeth reinforcement with MTA, Biodentine and Bioaggregate as an apical plug and backfill material using Finite Element Method. METHODS: A 3D finite element analysis model was generated using a simulated immature maxillary central incisor. Seven different models were developed representing (Model 1): control group having an immature tooth model without any reinforcement material; (Model 2): Mineral trioxide aggregate (MTA) as apical plug 4 mm; (Model 3): Biodentine as apical plug 4 mm; (Model 4): Bioaggregate as apical plug 4 mm; (Model 5): MTA filled in the entire root canal 8.5 mm; (Model 6): Biodentine filled in the entire root canal 8.5 mm; (Model 7): Bioaggregate filled in the entire root canal 8.5 mm. A force of 100 N was applied at an angle of 130° to the palatal surface of the tooth. Stress distribution at cemento­enamel junction was measured using the Von Mises stress criteria. RESULTS: It was found that the 4 mm apical plug using MTA showed higher fracture resistance when compared to 8.5 mm backfill using MTA. When MTA was replaced as backfill material by Biodentine and Bioaggregate, the von mises stress increased by 64% and 94% respectively. CONCLUSIONS: It is not desirable to restore the entire root canal of an immature teeth using same material due to higher stress concentration at the cervical region. Considering the shorter setting time and improved handling characteristics, Biodentine can be preferred over the time­tested MTA as an apical plug.

Comparative evaluation of calcium release of the apical plugs formed by mineral trioxide aggregate, Biodentine, and EndoSequence root repair material with and without 2% triple antibiotic powder: An in vitro study.

BACKGROUND: Apical plug formation by mineral trioxide aggregate (MTA), Biodentine, and EndoSequence root repair material (RRM) is an excellent alternative technique to the conventional apexification procedure. Several antimicrobial agents have been incorporated in MTA and Biodentine to boost their antimicrobial efficacy. Considering the polymicrobial nature of root canal infection, a combination of potent antimicrobials like triple antibiotic powder (TAP) would be needed to address the diverse flora encountered. Calcium release is the consequential factor in the clinical excellence of these cements. AIM: The aim of the study was to evaluate and compare the calcium released from the apical plugs formed by MTA, Biodentine, and EndoSequence RRM with and without incorporation of 2% TAP. METHODS: Ninety single-rooted teeth were divided into (n = 15) Group A: MTA + 2% TAP, Group B: MTA, Group C: Biodentine + 2% TAP, Group D: Biodentine, Group E: EndoSequence RRM + 2% TAP, and Group F: EndoSequence RRM to form the 4 mm apical plugs. Each sample tooth was then immersed in 10 ml of deionized water. Evaluation of calcium release was done on days 7, 15, and 30 using an atomic absorption spectrophotometer. Data were analyzed using one-way analysis of variance, post hoc test, and unpaired t-test. RESULTS: Calcium released was maximum for Group E compared to Group F (P < 0.05), maximum for Group C compared to Group D, and was maximum for Group A compared to Group B (P < 0.05) at days 7, 15 and 30. CONCLUSION: Incorporation of 2% TAP resulted in increased calcium ions released from MTA, Biodentine, and EndoSequence RRM.

Porosity Distribution in Apically Perforated Curved Root Canals Filled with Two Different Calcium Silicate Based Materials and Techniques: A Micro-Computed Tomography Study.

The present study evaluated the porosity distribution of BioRoot RCS/single gutta-percha point (BR/SC) and MTA flow (MF) fillings, which were used as plugs for the apical perforation repair in curved canals of extracted mandibular molars using micro-computed tomography (µCT). Forty mesial root canals of mandibular first molars were shaped with ProTaper NEXT X1-X5 files 2 mm beyond the apex to simulate apical perforations that were randomly divided into two groups (n = 20) according to the material and technique used for the apical plug: BR/SC or MF. The specimens were scanned before and after canal filling at an isotropic resolution of 9.9 µm. The volumetric analysis of voids in the apical 5 mm of the fillings was performed. Data were analyzed using one-way ANOVA with Bonferroni correction (p < 0.05). Micro-computed tomography (µCT) evaluation revealed significant differences between the groups in terms of porosity: the total volume and percentage volume of voids was lower in the BR/SC group in comparison with the MF group (p < 0.05), with the predominance of open pores in both groups. Neither of the materials and/or application techniques were able to produce void-free root fillings in the apical region of artificially perforated curved roots of mandibular molars.

Non-surgical endodontic management of immature permanent mandibular first molar: a 3 year follow-up.

BACKGROUND: Deep carious lesions in immature permanent molars with pulp necrosis pose a serious challenge to contemporary paedodontic practice. A further complex clinical scenario is an immature permanent molar with varying root formation in both roots. This case report demonstrates the successful management of an immature permanent mandibular first molar. CASE REPORT: An 8-year-old boy was referred for endodontic management of 36 by a general practitioner. After clinical and radiographic evaluation, a diagnosis of recurrent chronic periapical abscess with abrupt root closure in the mesial root and cessation of root closure in the distal root was made. Apexification was undertaken in three appointments. In the first appointment, under local analgesia and isolation, the mesial canals were prepared to size #F3 with rotary Protaper Universal and the distal canal was left unprepared. Both canals were irrigated with 5% sodium hypochlorite and calcium hydroxide intracanal medicament was placed. One week later, the mesial canals were obturated and a 4 mm white MTA apical plug was placed in the distal canal. Partial extrusion of the MTA was seen periapically. After 24 h, the hard-setting of the MTA plug was verified, remainder of the distal canal was obturated and core filling was placed followed by a preformed metal crown as an intermediate restoration. FOLLOW-UP: The patient was asymptomatic and showed resolution of the lesion, normal thickness of the PDL space with continuity of the lamina dura after 12 months. Extruded MTA was partially resorbed. Three years follow-up showed complete resorption of the extruded MTA and an intact lamina dura.

Revascularization and Apical Plug in an Immature Molar.

Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient's symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development.

Effect of Mineral Trioxide Aggregate Apical Plug Thickness on Fracture Resistance of Immature Teeth.

INTRODUCTION: The aim of this study was to compare the fracture resistance of simulated immature teeth after using different thicknesses of mineral trioxide aggregate (MTA) apical plugs. METHODS: Fifty-two human maxillary anterior teeth were used. Five teeth were the positive control group; they were prepared using Peeso reamers to simulate immature teeth without any access cavity preparation. Access cavities of the 47 teeth were prepared, and the canals were instrumented with Peeso reamers. Five teeth served as the negative control; they were filled with calcium hydroxide. Forty-two teeth were divided into 3 groups; in groups 1, 2, and 3, MTA was placed into canals as a 3-mm and a 6-mm apical plug and a thorough canal length, respectively. The rest of the canals in groups 1 and 2 were filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). After the storage period, the roots were covered with a polyether impression material and were embedded into self-curing resin blocks. Each specimen was then subjected to fracture testing using a universal testing machine. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons. RESULTS: The negative group showed the lowest fracture resistance compared with the other groups. The 3-mm apical plug group showed the highest fracture resistance (P < .05). No significant differences were found between the 3-mm and 6-mm apical plug groups (P > .05). CONCLUSIONS: MTA should be used as an apical plug instead of root canal filling material to increase the fracture resistance of immature teeth.

Comparative Micro-computed Tomographic Evaluation of the Sealing Quality of ProRoot MTA and MTA Angelus Apical Plugs Placed with Various Techniques.

INTRODUCTION: This study compared the effects of different mixing and placement techniques on sealing of ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland) and MTA Angelus (Soluçoes Odontologicas, Londrina, Brazil) apical plugs using micro-computed tomographic (micro-CT) imaging. METHODS: Standardized divergent open apex models were created using 120 extracted maxillary incisors and divided into 8 groups (n = 15). ProRoot MTA and MTA Angelus were mixed manually or mechanically and introduced to form apical plugs by hand condensation or indirect ultrasonic activation for 10 seconds. The samples were scanned using micro-CT imaging, and volumetric analysis of the voids between the dentin walls and the apical plugs and the porosity inside MTA was performed. RESULTS: Irrespective of the mixing and placement techniques used, the voids between the dentin walls and the apical plugs in the MTA Angelus groups were greater than those in the ProRoot MTA groups (P < .05). The mechanically mixed groups were significantly less porous than the manually mixed groups (P < .05). Combined mechanical mixing and indirect ultrasonic activation yielded a less porous structure for both types of MTA than combined manual mixing and hand condensation (P < .05). Marginal adaptation for ProRoot MTA, both mixed and placed manually, was greater than for MTA Angelus (P < .05), but no difference was found when indirect ultrasonic activation was performed (P > .05). CONCLUSIONS: ProRoot MTA showed better marginal adaptation than MTA Angelus. Mechanically mixed products had better handling characteristics than the manually mixed product. Indirect ultrasonic activation did improve the adaptation of manually mixed MTA Angelus to the dentin walls.

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.