Short-term periradicular tissue response to mineral trioxide aggregate (MTA) as root-end filling material

AIM: The aim of the present study was to evaluate the short-term response of periradicular tissues to MTA when used as a root-end filling material in ideal tissue conditions. METHODOLOGY: The experimental procedures were performed on the healthy teeth of dogs. Pulps were removed and root canals prepared and filled with gutta-percha and sealer. At the same session, buccal mucoperiosteal flaps were reflected and the root ends resected. MTA or IRM were used as root-end filling materials. The periradicular tissue reactions were evaluated histologically from 1 to 5 weeks. Hard tissue formed on the MTA surface was further examined by scanning electron microscopy. RESULTS: The most characteristic tissue reaction to MTA was the presence of connective tissue after the first postoperative week. Inflammation was seen occasionally. Early tissue healing events after MTA root-end filling were characterized by hard tissue formation, activated progressively from the peripheral root walls along the MTA-soft tissue interface. In contrast, hard tissue was not seen over the IRM root-end filling. CONCLUSIONS: MTA is a biocompatible material that stimulates periradicular tissue repair at the root-end situation; however, the nature of the newly formed tissues requires further elucidation.     

银汞材料与MTA材料作为根尖倒充填材料的临床效果评价

目的比较银汞材料与MTA材料作为根尖倒充填材料的不同临床疗效。方法采集既往实施根尖外科手术病例86例,按倒充填材料不同分为2组,A组47例,用MTA材料;B组39例,用银汞合金胶囊。2组均在根管显微镜下使用超声器械进行根尖倒预备。根据临床及X线片判定标准判定术后疗效,分为完全愈合、不完全愈合、不确定愈合、失败4组,统计术后1年手术成功率。结果不同的倒充填材料间成功率比较无统计学差异。结论银汞合金与MTA材料在显微超声根尖倒预备中,作为倒充填材料的临床效果无显著性差异。     

MTA用于根管倒充填临床疗效观察

目的:观察MTA用于根管倒充填的临床疗效.方法:选择需要进行根管外科的病人92例95个患牙,常规牙龈切开,暴露根尖,3例因根裂拔除,其余常规根尖切除,断面处用超声根尖工作头预备与牙体长轴平行的盒型洞,洞深约3 mm,MTA倒充填,术后3、6个月、1年复查.结果:1年复查时,有80例病人82个患牙复诊,74例76个牙成功,2例可疑.4例失败.成功率为92.7%.结论:MTA用于根管倒充填,疗效满意.     

A comparison of MTA, Super-EBA, composite and amalgam as root-end filling materials using a bacterial microleakage model

AIM: The aim of this study was to compare traditional and newly developed root-end filling materials for resistance to bacterial microleakage. METHODOLOGY: Sixty extracted single-rooted teeth were randomly divided into five groups for root-end filling with mineral trioxide aggregate, Super-EBA, TPH composite resin with ProBond dentine bonding agent, Dispersalloy amalgam with and without ProBond, and positive and negative control groups. Root canals were instrumented using the step-back technique and simulated root-end resections performed. Root-end filling materials were placed in 3 mm ultrasonic retropreparations. Nail varnish was applied to all external root surfaces to the level of the resected root ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 h. Using a newly designed model system, the apical 3-4 mm of the roots were immersed in BHI culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 h with a suspension of Streptococcus salivarius. Culture media were observed every 24 h for colour change indicating bacterial contamination. Media demonstrating colour change were plated for S. salivarius. Samples were observed for 12 weeks. RESULTS: At 4 weeks 10% of specimens from each experimental group had evidence of leakage. At 8 weeks 20% of specimens filled with amalgam without dentine bonding agent, Super-EBA and MTA had evidence of leakage. At 12 weeks minor differences between materials were noted. CONCLUSIONS: Under the conditions of the study, despite some variations, there were no statistically significant differences in rate of microleakage among the five groups tested at either 4, 8 or 12 weeks.     

牙本质黏结剂增强根管倒充填材料密闭性能的实验研究

目的观察在使用MTA进行根尖倒封闭术时,牙本质粘结剂对其密闭抗微渗漏的影响.方法取40颗离体单根恒牙,分别用MTA、MTA 牙本质粘结剂进行根尖倒封闭术,用染料渗透法检测根尖微渗漏的情况.结果MTA 牙本质粘结剂组的根尖密闭效果明显优于单纯使用MTA组,其差别具有统计意义(P<0.05).结论在使用MTA进行根尖倒封闭术时,使用牙本质粘结剂可提高充填体的密闭效果.     

Histological evaluation of MTA as a root-end filling material

AIM: To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored. METHODOLOGY: Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using anova analysis and Tukey's test. RESULTS: A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls. CONCLUSIONS: GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present.     

Randomized clinical trial of root-end resection followed by root-end filling with mineral trioxide aggregate or smoothing of the orthograde gutta-percha root filling – 1-year follow-up

Aim  To compare healing after root-end resection with a root-end filling of mineral trioxide aggregate (MTA) or smoothing of the orthograde gutta-percha (GP) root filling.
Methodology  Forty-four patients (consisting of 52 teeth with periapical infection), average age of 54.6 years (range 30–77) participated in a randomized clinical trial (RCT) comparing the MTA and GP treatment methods. Radiographs produced 1-week and 12 months post-operatively were compared after blinding for treatment method, and healing was assessed as complete, incomplete, uncertain, or unsatisfactory.
Results  Six teeth were not available for the 12-month follow-up: three teeth (GP) had been re-operated because of pain and two teeth (one GP, one MTA) had been extracted because of root fracture (these five teeth were classified as failures). One patient (GP) was not available for recall. In the GP group, seven teeth (28%) showed complete healing, six teeth (24%) incomplete healing, six teeth (24%) uncertain healing and two teeth (8%) unsatisfactory healing after 1 year. In the MTA group, 22 teeth (85%) showed complete healing, three teeth (12%) incomplete healing, and none were scored as uncertain or unsatisfactory healing after 1 year. The difference in healing between the GP and the MTA groups was significant ( P  <   0.001).
Conclusions  The results from this RCT emphasize the importance of placing a root-end filling after root-end resection. Teeth treated with MTA had significantly better healing (96%) than teeth treated by smoothing of the orthograde GP root filling only (52%).     

Treatment of a non-vital immature incisor with mineral trioxide aggregate (MTA)

Abstract  – A case of severe crown fracture and luxation in the upper permanent incisors of a 9-year-old boy is reported. The treatment of one of the injured teeth included apexification with calcium hydroxide and endodontic treatment with gutta-percha obturation. The other incisor was also treated with calcium hydroxide, but as there was no apical stop after 3 years of treatment, it was decided to use a new root-end filling material: mineral trioxide aggregate (MTA). At follow-up 12 months later, the tooth was asymptomatic and radiographically showed the initial repair of the radiolucent apical lesion.     

Contamination of tooth-colored mineral trioxide aggregate used as a root-end filling material: a bacterial leakage study

This experiment investigated the ability of tooth-colored mineral trioxide aggregate (MTA) to maintain an apical seal in the presence of bacteria when contaminated with blood, saline or saliva. Ninety extracted human teeth with single canals were randomly placed into six groups of 15. Canals were prepared to size 50. The apical 3 mm of each root was removed and 3 mm root-end preparations were made with a #329 bur. Root-end preparations in groups 1 through 3 were filled with MTA after contamination with blood, saline, or saliva, respectively. In group 4, uncontaminated root-end preparations were filled with MTA. Groups 5 and 6 served as negative and positive controls. A tube/tooth assembly was utilized to suspend each root end in Trypticase Soy Broth (TSB). The access chambers were filled with Staphylococcus epidermidis. Positive growth over thirty days was demonstrated by turbidity of the TSB. Vitek analysis was used to confirm the presence of S. epidermidis in the positive samples. Data evaluation consisted of a chi(2) analysis (p < 0.05). Although all experimental groups demonstrated leakage, tooth-colored MTA contaminated with saliva (group 3) leaked significantly more than the uncontaminated tooth-colored MTA (group 4) (p = 0.028).     

Sealing ability of Biodentine versus ProRoot mineral trioxide aggregate as root-end filling materials

Aim

This study evaluated the sealing ability of ProRoot MTA and Biodentine as root-end filling materials.

Comparison of microleakage with three different thicknesses of mineral trioxide aggregate as root-end filling material

The aim of this study was to compare the microleakage at three different thicknesses of mineral trioxide aggregate (MTA) as a root-end filling material. Ninety extracted human maxillary incisor teeth were selected and the root canals of the teeth were cleaned, shaped and obturated with gutta percha and AH-plus sealer. Teeth were randomly divided into 3 groups each containing 20 experimental samples, and 5 positive and 5 negative controls. In the first, second and third experimental groups, cavities of 1 mm, 2 mm and 3 mm in depth, respectively, were prepared and filled with MTA. Leakage was determined by the dye penetration method using India ink, and a stereomicroscope at x16 magnifications and 0.1 mm accuracy. The microleakage in the 3-mm and 2-mm root-end cavities was less than at 1 mm depth, but analysis of variance revealed no significant differences among the three different thicknesses.     

SEM evaluation of neodentinal bridging after direct pulp protection with mineral trioxide aggregate

The purpose of this study was to observe the basic morphology and determine the chemical composition of neodentinal bridges adjacent white mineral trioxide aggregate (WMTA) when used as a direct pulp capping material. The experimental procedures were performed on six intact dogs' teeth. The pulps were exposed and cavities were filled with WMTA. After 2 weeks, neodentinal bridge formation was evaluated by scanning electron microscope (SEM) of cross-sections of the specimens and electron probe microanalysis (EPMA) of the pulpal surfaces. Results of SEM observation showed that the most characteristic reaction of pulp cells was the intimate connection of cell processes and secreted extracellular fibres with the crystals of the pulp capping material. Results of EPMA indicated that the mineralisation of neodentinal bridge formation occurred progressively from the periphery to the central area. Based on these results, it appears that WMTA has the potential to be used as a direct pulp capping material during vital pulp therapy.     

Effect of pH on sealing ability of white mineral trioxide aggregate as a root-end filling material

The aim of the present study was to evaluate microleakage of mineral trioxide aggregate (MTA) used as a root-end filling material after its exposure to a range of acidic environments during hydration. Seventy single-rooted teeth were divided into 4 experimental and 2 control groups. All the teeth were instrumented, and their apices were resected. Root-end cavities were filled with white MTA in the experimental groups. In the control groups root-end cavities were not filled. Root-end fillings were exposed to acidic environments with pH values of 4.4, 5.4, 6.4, or 7.4 for 3 days in the experimental groups. Microleakage was evaluated by using bovine serum albumin. The evaluation was conducted at 24-hour intervals for 80 days. Data were analyzed by using one-way analysis of variance and a post hoc Tukey test. The earliest bovine serum albumin microleakage was observed in a pH value of 4.4 followed by pH values of 5.4, 6.4, and 7.4, respectively. There was a significantly longer time necessary for leakage to occur in samples stored in higher pH values (P < .000).     

A prospective clinical study of periradicular surgery using mineral trioxide aggregate as a root-end filling

A prospective outcome study of periradicular surgery using microsurgical techniques and root-end filling with mineral trioxide aggregate (MTA) was performed. Nonhealing endodontically treated teeth (n = 321) were included in the study. Surgery was completed under local anesthesia using a standardized clinical protocol. Patients were recalled periodically and examined for signs and symptoms of failure. Thirty-nine teeth were lost from recall. Of the 276 teeth examined, 163 showed complete healing radiographically with no other signs and symptoms; 82 teeth had no symptoms but incomplete or uncertain healing, and 31 teeth showed nonhealing (three had persistent pain despite evidence of complete radiologic healing and eight teeth did not heal for reasons unrelated to the surgical treatment). The overall success rate was 88.8%, including all teeth with no clinical symptoms. In this study, the use of MTA as a root-end filling, following microsurgical techniques, showed a high success rate.     

The dentinogenic effect of mineral trioxide aggregate (MTA) in short-term capping experiments

AIM: The objective of the present experiment was to study the early pulpal cell response and the onset of reparative dentine formation after capping application of MTA in mechanically exposed pulps. METHODOLOGY: Thirty-three teeth from three dogs, 12-18 months of age were mechanically exposed via class V cavities. Light pressure was applied to control haemorrhage. ProRoot MTA (Dentsply Simfra, Paris) was placed at the exposure site and light pressure was applied with a wet cotton pellet. The cavities were restored with amalgam and the pulpal tissue reactions were assessed by light and electron microscopy (transmission and scanning) after healing intervals of 1, 2 or 3 weeks. RESULTS: A homogenous zone of crystalline structures was initially found along the pulp-MTA interface, whilst pulpal cells showing changes in their cytological and functional state were arranged in close proximity to the crystals. Deposition of hard tissue of osteotypic form was found in all teeth in direct contact with the capping material and the associated crystalline structures. Formation of reparative dentine (tubular matrix formation in a polar predentine-like pattern by elongated polarized cells) was consistently related to a firm osteodentinal zone. CONCLUSIONS: The present experiments indicate that MTA is an effective pulp-capping material, able to stimulate reparative dentine formation by the stereotypic defensive mechanism of early pulpal wound healing.     

恒磨牙MTA直接盖髓术的临床疗效观察

目的：观察MTA在磨牙深龋意外露髓时直接盖髓术的临床疗效。方法：磨牙深龋意外露髓病例60例60个患牙,随机分为治疗组和对照组,分别用MTA和氢氧化钙进行直接盖髓术,治疗后1、3、6个月复查,观察盖髓术后临床成功率,并进行统计学分析。结果：治疗组的成功率为83．3％,明显高于对照组的成功率53．3％,组间比较差异有统计学意义（P＜0．05）。结论：MTA应用于磨牙深龋意外露髓直接盖髓术时临床疗效好。     

Occlusal loading of EBA and MTA root-end fillings in a computer-controlled masticator: a scanning electron microscopic study

AIM: The aim of this investigation was to assess the marginal adaptation of Super-EBA (EBA) and Pro Root MTA (MTA) root-end fillings and the occurrence of microcracks in resected root-ends of extracted teeth before and after occlusal loading for a five-year equivalent period in a computer-controlled masticator. METHODOLOGY: Twenty-four molar teeth were root-filled using lateral condensation and their root-ends resected. Root-end cavities were prepared and either EBA or MTA root-end fillings were placed. All surgical procedures were completed in vitro under an operating microscope. Replicas taken of the root-end fillings and resected root-ends were examined using an SEM before and after they were subjected to in vitro chewing cycles in a computer-controlled chewing simulator for the equivalent of 5 years. Marginal adaptation and integrity of the two root-end filling materials were evaluated and the presence of microcracks recorded. RESULTS: Before loading, a continuous margin was observed with 99.4 +/- 2.4% of EBA and 99.2 +/- 1.6% of MTA root-end fillings. After loading, the percentage of continuous margin decreased to 93.1 +/- 6.6% and 98.9 +/- 3.2% for EBA and MTA, respectively. After occlusal loading, 39.5% of the EBA root-end fillings were overfilled, whilst 52.6% of the MTA root-end fillings were underfilled. In total, 12.5% of the resected root-end surfaces showed microcracking before loading and 25% after occlusal loading. CONCLUSIONS: Both EBA and MTA displayed excellent marginal adaptation before masticatory loading. After loading, the amount of continuous margin for both root-end filling materials decreased slightly but was still high.     

Cytotoxicity of calcium enriched mixture cement compared with mineral trioxide aggregate and intermediate restorative material

Calcium enriched mixture (CEM) cement has been recently invented by the last author. It is composed of calcium oxide, calcium phosphate, calcium silicate and calcium sulphate; however, it has a different chemical composition to mineral trioxide aggregate (MTA). The purpose of this ex vivo study was to investigate the cytotoxicity of CEM cement, and compare it with intermediate restorative material (IRM) and MTA. The materials were tested in fresh and set states on L929 fibroblasts to assess their cytotoxicity. The cell viability responses were evaluated with methyl‐tetrazolium bromide assay and Elisa reader at 1, 24 and 168 h (7 days). The tested materials were eluted with L929 culture medium according to international standard organisation 109935 standard. Distilled water and culture medium served as positive and negative controls, respectively. Differences in cytotoxicity were evaluated by one‐way anova and t‐tests. The cytotoxicity of the materials was statistically different at the three time intervals (P < 0.01). The lowest cytotoxic values recorded were expressed by MTA subgroups followed by CEM cement; IRM subgroups were the most cytotoxic root‐end/dental material (P < 0.001). CEM cement and MTA are reasonable alternatives to IRM because of lower cytotoxicity. CEM cement also has good biocompatibility as well as lower estimated cost to MTA and seems to be a promising dental material.