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.     

Dentin bridge formation after white mineral trioxide aggregate (white MTA) pulpotomies in primary molars

PURPOSE: To evaluate, clinically and radiographically, the dentin bridge formation potential of white mineral trioxide aggregate (white MTA) when used in pulpotomy treatments in primary molars. METHODS: A total of 23 primary molars received a pulpotomy treatment using white MTA followed by stainless steel crown restoration and controlled 6 months after treatment. RESULTS: Clinical and radiographic success was 100% as none of the molars showed any clinical or radiographic pathological signs. Reparative dentin deposition was found in some of the cases: stenosis was present in 69.2% of the pulp canals from mandibular molars and formation of dentin bridges was seen in 11.5% of the pulp canals from mandibular molars 6 months after treatment with white MTA.     

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.     

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.     

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.     

Mineral trioxide aggregate (MTA) solubility and porosity with different water-to-powder ratios

This study tested mineral trioxide aggregate (MTA) solubility and porosity with different water-to-powder proportions. The study also determined the chemical composition of the salts dissolved by MTA. Four sets of specimens using the following water-to-powder proportions were prepared: 0.26, 0.28, 0.30, and 0.33 grams of water per gram of cement. The latter is the ratio recommended by the manufacturer. It was determined that the degree of solubility and porosity increased as the water-to-powder ratio increased. Significant differences were found among the sets of specimens. The chemical analyses of the salts dissolved by MTA in the water identified the presence of calcium as the main chemical compound. The pH level of the solution was highly alkaline, ranging between 11.94 and 11.99. It can be stated that the calcium found in the solution should be in its hydroxide state at this high pH level. This ability to release calcium hydroxide could be of clinical significance because it could be related to the proven capacity of MTA to induce mineralization.     

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.     

Use of mineral trioxide aggregate (MTA) in root repairs. Clinical cases

Several clinical situations, such as lateral root or furcation perforation during endodontic treatment, apexification and/or apicoectomy, require the use of reliable materials and techniques to address the problem. The materials historically used for these conditions do not provide a reliable clinical outcome nor a long-term prognosis. New materials and technology may help this challenging issue. Ideally, the repair material should be nontoxic, bacteriostatic and nonresorbable; should promote healing; and should provide an optimal hermetic seal. Among different materials usually used for this purpose--amalgam, ZOE, ZOP, gutta-percha, IRM, Super-EBA, glass ionomers, calcium hydroxide, bonding agents, Cavit, hydroxyapatite and, finally, mineral trioxide aggregate--only the last has provided a substantial advantage.     

Human pulpal response to mineral trioxide aggregate (MTA): a histologic study

The purpose of this study was to study the histologic changes in the dental pulp following pulpotomy with Mineral Trioxide Aggregate (MTA) and Calcium hydroxide. Pulpotomies were performed on premolar teeth that were to be extracted for orthodontic reasons. The radicular pulp was capped with either MTA or Calcium hydroxide and restored with IRM. The teeth were extracted at 4 and 8 week intervals, fixed in 10% formalin and then kept in 5% nitric acid for 28 days for demineralization. Longitudinal sections were then prepared and viewed under light microscope. The pulps capped with MTA (at the end of 4 weeks and 8 weeks) showed dentin bridge formation which was more homogenous and continuous with the original dentin when compared to the pulps capped with calcium hydroxide. The pulpal inflammation was also less in the MTA group as compared to the calcium hydroxide group at the end of 4 and 8 weeks.     

Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study

AIM: To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. METHODOLOGY: Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. RESULTS: Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). CONCLUSIONS: This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.     

Scanning electron microscopy evaluation of the hard tissue barrier after pulp capping with calcium hydroxide,mineral trioxide aggregate (MTA) or ProRoot MTA

The aim of this study was to investigate the morphology and localisation of calcium hydroxide‐ and mineral trioxide aggregate (MTA)‐induced hard tissue barriers after pulpotomy in dogs' teeth. Pulpotomies were performed on maxillary and mandibular premolars of five dogs. The teeth were assigned into three groups according to the pulp‐capping agent used. The pulpal wounds were capped with calcium hydroxide (Ca(OH)₂– control), MTA or ProRoot MTA, and the cavities were restored with amalgam. After a 90‐day follow‐up period, the dogs were euthanised and the teeth were examined under scanning electron microscopy (SEM). An image‐processing and analysis software was used to delimit the perimeters of the root canal area and the hard tissue barrier to determine the percentage of root canal obliteration. SEM data were used to assess the morphology, localisation and extension of the reparative hard tissue barriers. ProRoot MTA was statistically different from MTA and Ca(OH)₂ (P < 0.05) regarding tissue barrier morphology. Localisation data showed that ProRoot MTA was significantly different from Ca(OH)₂ (P < 0.05) and similar to MTA (P > 0.01; P > 0.05). No statistically significant difference (P > 0.01; P > 0.05) was observed between MTA and Ca(OH)₂. A larger number of complete (centroperipheral) hard tissue barriers with predominance of dentinal tubules was observed to the ProRoot MTA when compared with the Ca(OH)₂ group.     

Clinical outcomes of artificial root-end barriers with mineral trioxide aggregate in teeth with immature apices

The purpose of this retrospective study was to evaluate the clinical outcomes of ProRoot mineral trioxide aggregate used as an artificial apical barrier in teeth with immature apices. Twenty teeth from 19 patients were included in this study. A healed diagnosis was based on periapical index scores of 1 or 2 and no clinical signs or symptoms at recall examinations. Eighty-five percent (17/20) of these teeth were healed, and improvements in periapical index scores at recall appointments were shown to be statistically significant (P < .001, Wilcoxon signed-rank test). Chi-square test indicated that age, gender, primary treatment versus retreatment, presence of preoperative lesion, and differences in recall times did not significantly influence healing outcome. Overall, these results indicated that the mineral trioxide aggregate apical barrier technique is a successful method for obturating teeth with immature apices.     

Clinical assessment of mineral trioxide aggregate (MTA) as direct pulp capping in young permanent teeth

Carious pulp exposure in permanent molars of children is a common incident. Mineral trioxide aggregate is a new material that possesses numerous exciting possibilities for pulp therapy. AIM: The purpose of this study was to evaluate the efficiency of MTA as a direct pulp capping agent in young permanent teeth. METHODS: Thirty asymptomatic permanent molars with pulp exposures were treated by pulp capping using MTA. At each recall (6 12, 18 and 24 months), the teeth were assessed clinically, through pulpal sensitivity tests, as well as radiographically to evaluate periapical healing. RESULTS: None of the cases reported spontaneous pain at the six months follow up and the pulp showed signs of vitality and absence of periapical radiolucency. At 24 months, the clinical and radiographic success rate was 93% with evidence of continued root growth. CONCLUSION: Pulp capping with MTA is recommended for teeth with carious pulp exposures specially immature teeth with high potential for healing.     

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.

Use of mineral trioxide aggregate (MTA by postgraduates in restorative dentistry in the UK

All postgraduate trainees in Restorative Dentistry within the United Kingdom were contacted by e-mail and invited toparticipate in a structured on-line questionnaire regarding MTA usage. Responses were received from 46/65 (70.8%) postgraduate trainees. MTA was used by 15/46 (32.6%) trainees in the primary dentition and 46/46 (100%) in the permanent dentition. Barriers to the use of MTA in the permanent dentition related to material cost and in the primary dentition, the lack of an evidence base. Overall, 32/46 (69.6%) had received tuition during their postgraduate programme and 21/46 (45.7%) indicated an interest in further educational opportunities in material use.     

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。