Long-term seal provided by some root-end filling materials

Sealing Ability of Bioactive Root-End Filling Materials in Retro Cavities Prepared with Er,Cr:YSGG Laser and Ultrasonic Techniques

The aim of this in vitro study was to compare the apical sealing ability of total fill bioceramic root repair material (BC-RRM) and mineral trioxide aggregate (MTA), regarding the retrograde preparation technique used: ultrasonic or erbium, chromium: yttrium, scandium, gallium, or garnet (Er,Cr:YSGG) laser. The study sample consisted of 48 human single-rooted teeth. After root-end resection, the samples were divided into two groups, according to the retrograde preparation technique used: Group 1: ultrasonic; Group 2: Er,Cr:YSGG laser. In each group, half of the retrograde cavities were filled with BC-RRM, and the other half were filled with MTA. The specimens were mounted in tubes and sterilized in plasma. The root canals were inoculated with Enterococcus faecalis, and the tubes were filled with fetal bovine serum, leaving the apical part of the root in the serum. After 30 days, the canals were sampled and cultured, and the colony forming units (CFUs) were counted with the additional polymerase chain reaction (PCR analysis). There was no significant difference between ultrasonic groups and the Er,Cr:YSGG-MTA group, regarding the number of CFUs (p > 0.05). The Er,Cr:YSGG-BC-RRM group showed the highest number of remaining viable bacteria (p < 0.001). Both filling materials filled in ultrasonic preparations presented similar sealing abilities. The BC-RRM showed more leakage when used in retro cavities prepared with the Er,Cr:YSGG laser.

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

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

Nonsurgical Management of Apical Root Perforation Using Mineral Trioxide Aggregate

This study illustrates a conservative approach to nonsurgical management of apical root perforation in maxillary first molars. A patient was referred for retreatment of a maxillary left first molar. Her chief complaint was dull pain while biting in her maxillary left first molar. Periapical radiography showed radiolucency related to the mesiobuccal root and overextended gutta-percha through a perforation in the apical part of the distobuccal root. A CBCT scan was acquired and revealed the location and size of the apical perforation. The clinical examination showed that the tooth has been endodontically treated and the canals were filled, tender to percussion and palpation. Thus, the nonsurgical root canal retreatment was done and the perforation site was repaired by using mineral trioxide aggregate (MTA). At the one-year follow-up, after the management of apical root perforation, we observed periapical tissue healing and no pain due to percussion and palpation, without any clinical/radiological signs or symptoms. The prognosis of this case has a higher success rate with the development of new materials such as MTA. The MTA not only can seal the site of the perforation but also has the ability to induce calcification. Many factors can contribute to the success rate of perforated cases, including time, size, and location of the perforation. With the use of this material and good tools like a microscope, there are those with having higher chances of repair and eventually higher success rates.

Synthesis and characterization of novel calcium phosphate glass-derived cements for vital pulp therapy

Evaluation of the physicochemical behavior and setting reactions of a novel inorganic pulp capping cement which makes use of the unique corrosion properties of sodium metasilicate (NaSi) glass. NaSi and calcium phosphate (CaP) glass powders were synthesized through a melt-quench method. Cements were created by mixing various amounts of the glasses with deionized water at a powder-to-liquid ratio of 2.5 g mL^-1. Working and setting times were measured using the indentation standard ISO 9917-1. Sealing ability was tested by placing set samples of each composition in methylene blue dye solution for 24 h. Set samples were also submerged in phosphate buffered saline and incubated at 37 °C for one week. X-ray diffraction was used to identify mature crystalline phases after incubation. Infrared spectroscopy and scanning electron microscopy were used to characterize cements before and after setting and after incubation. Working and setting times measured in the ranges of 2-5 and 10-25 min, respectively. Working and setting time generally decrease with increased NaSi concentration. Cements with compositions of 25 and 33 wt% NaSi were found to resist the infiltration of dye and maintain their shape. Compositions outside this range absorbed dye and collapsed. Infrared spectroscopy provided insight into the setting mechanism of these cements. After one week in vitro, cements were found to contain crystalline phases matching chemically stable, bioactive phases. The combination of NaSi and CaP glasses has favorable setting behavior, sealing ability, and mature phases for pulp capping while relying on a relatively simple, inorganic composition.

The Effect of Resection Angle on Stress Distribution after Root-End Surgery

Introduction:

This study aimed to investigate the influence of the resection angle on the stress distribution of retrograde endodontic treated maxillary incisors under oblique-load application.

Methods and Materials:

A maxillary central incisor which was endodontically treated and restored with a fiber glass post was obtained in a 3-dimensional numerical model and distributed into three groups according to type of resection: control; restored with fiber post without retrograde obturation, R45 and R90 with 45º and 90º resection from tooth axial axis, respectively and restored with Fuji II LC (GC America). The numerical models received a 45^º occlusal load of 200 N/cm² on the middle of lingual surface. All materials and structures were considered linear elastic, homogeneous and isotropic. Numerical models were plotted and meshed with isoparametric elements, and the results were analyzed using maximum principal stress (MPS).

Results:

MPS showed greater stress values in the bone tissue for control group than the other groups. Groups with apicectomy showed acceptable stress distribution on the fiber post, cement layer and root dentin, presenting more improved values than control group.

Conclusion:

Apicectomy at 90^º promotes more homogeneity on stress distribution on the fiber post, cement layer and root dentin, which suggests less probability of failure. However, due to its facility and stress distribution also being better than control group, apicectomy at 45^° could be a good choice for clinicians.

Current status of direct pulp-capping materials for permanent teeth

Direct pulp-capping is a method for treating exposed vital pulp with dental material to facilitate the formation of reparative dentin and to maintain vital pulp. Two types of pulp-capping materials, calcium hydroxide and mineral trioxide aggregate, have been most commonly used in clinics, and an adhesive resin has been considered a promising capping material. However, until now, there has been no comprehensive review of these materials. Therefore, in this paper, the composition, working mechanisms and clinical outcome of these types of pulp-capping materials are reviewed.

Interface Between MTA and Dental Bonding Agents: Scanning Electron Microscope Evaluation

Aims and Objectives:

Nowadays, the material that offers the best sealing characteristic in the field of endodontic treatment is the mineral trioxide aggregate (MTA), nevertheless, this material necessities an adhesive bonding agent to perfectly join to the dental surface. The aim of this study was to analyze using a scanning electron microscope (SEM) the possible microgap between the adhesive, MTA, and the dental surface.

Material and Methods:

Fourteen extracted molars were divided into two groups – group A was prepared with MTA-component adhesive and group B was prepared with MTA and composite dual etching. The observations were carried out with a SEM Phenom G2 Pro mode S.E.I. JMP® software was used for statistical analysis, and a t-test was used for evaluating the difference between the two groups.

Results:

The gap of the areas at higher magnification (1000×) with a size greater than 5 microns in width and 20 microns in length were considered significant, and only group A recorded significant data.

Conclusions:

The SEM analysis performed in the group A with interposition of adhesive and flow between the dental pulp chamber and MTA demonstrates the presence of a marginal gap of considerable amplitude in the all of the samples investigated.

Comparison of the Root End Sealing Ability of Four Different Retrograde Filling Materials in Teeth with Root Apices Resected at Different Angles - An Invitro Study

INTRODUCTION

Insufficient apical seal is the significant reason for surgical endodontic disappointment. The root-end filling material utilized should avoid egress of potential contaminants into periapical tissue.

AIM

The aim of this study was to compare the sealing ability of four root-end filling materials MTA, Portland cement, IRM, RMGIC in teeth with root apices resected at 0 and 45 angle using dye penetration method under fluorescent microscope.

MATERIALS AND METHODS

Hundred extracted human maxillary anterior teeth were sectioned horizontally at the cement-enamel junction. After cleaning, shaping and obturation with gutta-percha and AH Plus sealer, the tooth samples were randomly divided in two groups (the root apices resected at 0° and 45° to the long axis of the root). The root resections were carried out by removing 2 mm and 1 mm in both the groups. Following which 3 mm deep root-end cavities were prepared at the apices and the root were coated with nail varnish except the tip. The teeth in both the group were randomly divided into four subgroups each (Pro root MTA, Portland cement, IRM and Light cure nano GIC Ketac N-100). All the retrofilled samples were stored in acrydine orange for 24 hours after which they were cleaned and vertically sectioned buccolingually. The sectioned root samples were observed under fluorescent microscope.

RESULTS

The root apex sealing ability of Mineral Trioxide Aggregate (MTA) was superior to Portland cement, Intermediate Restorative Material (IRM) and LC GIC. IRM demonstrated the maximum apical leakage value among all the materials. Portland cement and LC GIC showed comparable sealing ability.

CONCLUSION

The angulation whether 0° or 45° angle did not affect the sealing ability of all the four materials used, MTA proved to be one of the superior materials for root-end filling.

Comparative evaluation of sealing ability and microstructure of MTA and Biodentine after exposure to different environments

OBJECTIVES

The aim of this study was to evaluate the sealing ability and morphological microstructure of Biodentine in comparison to ProRoot mineral trioxide aggregate (MTA) after storage in an acidic environment.

MATERIALS AND METHODS

Biodentine and ProRoot MTA were prepared and packed into the canal lumen of dentin disks. Twenty specimens of each material were further randomly divided into two groups according to the storage media: group A: materials with saline as storage medium; group B: materials with citric acid buffered at pH 5.4 as storage medium. The sealing ability was evaluated at 1, 3, 6, and 24 h and 1 or 3 months, using a fluid transport model for quantitative analysis of endodontic microleakage. The morphological microstructures of the materials were also evaluated using scanning electron microscopy.

RESULTS

During the first 24 h, MTA showed greater fluid transport values than Biodentine in both environments. At the 3-month measurement, when the materials were stored in saline, MTA showed greater ability to prevent fluid movement than Biodentine (p < 0.0001). However, when the materials were stored in an acidic environment, no statistical significant difference was found after 3 months. After storage in saline, both materials showed an uneven crystalline surface with similar hexagonal crystals. The microstructure of Biodentine changed after exposure to citric acid, showing a relatively smooth surface with more spheroidal crystals.

CONCLUSIONS

The exposure to an acidic environment, within the limits of this study, seems to result in morphological changes of Biodentine in a different manner than MTA. MTA shows good ability to prevent fluid movement over time, in both environments. The ability of Biodentine to prevent fluid movement over time was enhanced in the acidic environment.

CLINICAL RELEVANCE

The findings of the present study could imply that both materials are indicated for use in an acidic environment.

Similar sealability between bioceramic putty ready-to-use repair cement and white MTA

This study was designed to assess the ability to prevent glucose penetration of a bioceramic putty ready-to-use repair cement comparing to white mineral trioxide aggregate (WMTA). After root canal instrumentation, the apical 3 mm of maxillary incisors were resected and root-end cavities with depth of 3 mm were prepared with ultrasound and filled with the tested materials (15 roots per group). All roots were mounted in a double chamber system to assess glucose penetration using 15 psi pressure application. After 1 h, glucose concentrations in the lower chamber were measured following an enzymatic reaction. Four roots were used as controls. The Mann-Whitney test verified differences in glucose leakage between groups and the Tukey's test was used for multiple comparisons. Significance level was set at 5%. There was no significant difference in glucose leakage between iRoot BP Plus and White MTA groups. iRoot BP Plus had a similar ability to that of white MTA in preventing glucose leakage as a root-end filling material.

The Effect of Thickness on the Sealing Ability of CEM Cement as a Root-end Filling Material

Background and aims. Different materials have been used for root-end filling during surgical endodontic treatment. The aim of this in vitro study was to evaluate the dye penetration in different thicknesses of calcium enriched mixture (CEM) cement as root-end filling material. Materials and methods. Following root canal filling in 70 extracted human single-rooted premolar teeth, the apical 3 mm of their root-ends was resected; the root-end cavities with depths of 1, 2 and 3 mm were prepared by ultrasonic retrotips and filled with CEM cement. After setting of cement, the roots were immersed in 2% Rhodamine B and the dye leakage was measured under stereomicroscope (×16) using Image J software. The data were analyzed by one-way ANOVA and Bonferroni post hoc tests at 5% significance level. Results. The means and standard deviations of dye penetration in the 1, 2, and 3 mm groups were 3395.5±1893.4, 3410.4±1440.5, and 2581.6±1852.9 μm, respectively. The one-way ANOVA analysis indicated significant differences (P < 0.001); however, the Bonferroni post hoc test revealed that only the positive control group differed significantly from the experimental groups (P < 0.001). Conclusion. The findings demonstrated CEM cement to have an adequate root-end sealing ability in 3-mm thickness.

Comparative evaluation of push-out bond strength of ProRoot MTA, bioaggregate and biodentine

OBJECTIVE

To evaluate the push-out bond strength of Biodentine (BD) in comparison with two available calcium silicate based materials, bioaggregate (BA) and ProRoot MTA (WMTA).

MATERIALS AND METHODS

One hundred and twenty-three Root dentin slices of freshly extracted single Rooted human teeth were randomly divided into three groups (n = 41) according to the used test material: WMTA, BA, BD. After canal space preparation, the filling materials were placed inside the lumen of the slices. After 72 hours, the maximum force applied to materials at the time of dislodgement was recorded and slices were then examined under a stereomicroscope at ×40 magnification to determine the nature of bond failure. Analysis of variance (ANOVA) test was used to compare means of push-out bond strength. Post-hoc test was then accomplished for multiple comparisons. Chi-square test was used to determine if there is significant association between the type of material and type of failure.

RESULTS

The mean push-out bond strength ± standard deviation in MPa values of WMTA, BA and BD were 23.26 ± 5.49, 9.57 ± 3.45, 21.86 ± 6.9, respectively. There was no significant difference between the means of WMTA and BD (p = 0.566), but the mean of BA was significantly lower than those of WMTA and BD (p = 0.000). Under stereomicroscope, WMTA and BA showed a majority of mixed type of failure than cohesive failure, while BD showed the opposite. No adhesive failure was observed in any specimen.

CONCLUSION

The findings of the present study imply that the force needed for BD displacement is similar to WMTA and significantly higher than the force required to displace BA.

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.

Calcium Hydroxide vs. Mineral Trioxide Aggregates for Partial Pulpotomy of Permanent Molars with Deep Caries

AIM

To prospectively compare the clinical success rate of partial pulpotomy treatment in permanent molars using calcium hydroxide (CH) and mineral trioxide aggregates (MTA) as pulp dressing agents.

METHODS

Restorable permanent first molars (64) with carious pulp exposures were randomly assigned to two groups; CH and MTA. A standardized operative procedure was followed in both groups. Following isolation and caries removal, the exposed superficial pulp tissue layers were removed with a sterile flame shape diamond bur to a depth of 2-4 mm. Bleeding was controlled and pulp dressed with either a paste of non-setting Ca(OH)2 followed by a setting layer of Ca(OH)2, or with grey MTA. The dressing materials in both groups were then covered with a layer of light cured glass ionomer cement. The teeth were either restored using amalgam, or where grossly carious with preformed metal crowns. Patients were scheduled for follow-up at 3, 6, 12 months and annually thereafter.

RESULTS

There were 34 patients (17 males and 17 females) with 51 teeth available for evaluation. The age of patients at the time of restoration ranged between 6.8 to 13.3 years (mean of 10.3 +/- 1.8 years). The follow-up period ranged from 25.4 to 45.6 months with an average of 34.8 +/- 4.4 months. There was no statistically significant difference in the success rate of teeth treated with CH (91%) in comparison to teeth treated with MTA (93%). Radiographically, a hard tissue barrier under CH was noticed in 12 (55%) teeth compared with 18 (64%) teeth under MTA (p=0.4).

CONCLUSIONS

MTA has clinical success rate comparable to CH as a pulp dressing material for partial pulpotomy in permanent molars with carious exposures.

Clinical applications of glass ionomers in endodontics: a review

Glass ionomer cements (GICs) are biocompatible and have capacities to release fluoride and to bond to dentine, and thus are appropriate for use in endodontics. This paper reviews the composition and properties of different GICs, including their biocompatibility and antibacterial activity, their applications as intraorifice barriers and root canal sealers, and their use in the repair of root perforations, root-end fillings and temporary coronal restorations.

Dynamic sealing ability of MTA root canal sealer

AIMS

To evaluate (i) the sealing ability of two sealers, mineral trioxide aggregate sealer (MTAS) and Pulp Canal Sealer (PCS), used with gutta-percha utilizing the fluid filtration method, (ii) leaching and surface characteristics in Hank's balanced salt solution (HBSS) over a period of time.

METHODOLOGY

Surface characteristics in HBSS were evaluated under the scanning electron microscope after 1 and 28 days, and the leaching of both sealers were assessed by inductively coupled plasma atomic absorption spectrometry (ICP-AAS). In addition, 24 single rooted extracted teeth were root filled using warm vertical compaction with either MTAS or PCS used as sealers with gutta-percha. Four teeth were used as positive and negative controls. Sealing ability was evaluated after 1 or 28 days using the fluid filtration method.

RESULTS

Mineral trioxide aggregate sealer exhibited crystalline deposits rich in calcium and phosphorus on its surface when in contact with a physiological solution. These crystalline deposits were absent in PCS and on MTAS stored at 100% humidity. The sealing ability of MTAS was similar to that of PCS.

CONCLUSIONS

The novel sealer based on mineral trioxide aggregate had comparable sealing ability to a proprietary brand sealer cement. In contact with a simulated body fluid, the MTA sealer released calcium ions in solution that encouraged the deposition of calcium phosphate crystals.

Endodontic essay

"It has been said that Mineral Trioxide Aggregate is driving an endodontic revolution. Discuss this statement considering the biological and clinical attributes of this innovative material."

Periradicular regeneration after endodontic surgery with calcium-enriched mixture cement in dogs

INTRODUCTION

The aim of this in vivo study was to compare the response of periradicular tissues to mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement as root-end fillings and to analyze hard tissue healing after periradicular surgery.

METHODS

Intentional periradicular lesions were induced in 32 premolar teeth in 4 beagle dogs. The root canals were prepared, dried, and obturated with laterally condensed gutta-percha with sealer, and the coronal access cavities were filled with amalgam. After surgical exposure of the apices, 2-3 mm of the apical root was resected, and root-end cavities were ultrasonically prepared. The root-end cavities were randomly filled with MTA or CEM cement. After 2 months, the animals were killed; tissue blocks were removed and prepared for histologic examination. Hard tissue healing including cementum and new bone formation in addition to concentration and extent of inflammation were evaluated.

RESULTS

Eight samples were excluded. The major finding was the cementum deposition adjacent to MTA in 11 of 12 samples and CEM cement in 10 of 12 samples. With one-way analysis of variance, no significant difference was observed between the periradicular tissue response to tested materials.

CONCLUSIONS

CEM cement and MTA were associated with regenerative periapical tissue response when used as root-end filling biomaterials.

Reparative dentinogenesis induced by mineral trioxide aggregate: a review from the biological and physicochemical points of view

This paper aims to review the biological and physicochemical properties of mineral trioxide aggregate (MTA) with respect to its ability to induce reparative dentinogenesis, which involves complex cellular and molecular events leading to hard-tissue repair by newly differentiated odontoblast-like cells. Compared with that of calcium hydroxide-based materials, MTA is more efficient at inducing reparative dentinogenesis in vivo. The available literature suggests that the action of MTA is attributable to the natural wound healing process of exposed pulps, although MTA can stimulate hard-tissue-forming cells to induce matrix formation and mineralization in vitro. Physicochemical analyses have revealed that MTA not only acts as a "calcium hydroxide-releasing" material, but also interacts with phosphate-containing fluids to form apatite precipitates. MTA also shows better sealing ability and structural stability, but less potent antimicrobial activity compared with that of calcium hydroxide. The clinical outcome of direct pulp capping and pulpotomy with MTA appears quite favorable, although the number of controled prospective studies is still limited. Attempts are being conducted to improve the properties of MTA by the addition of setting accelerators and the development of new calcium silicate-based materials.

The nociceptive and anti-nociceptive effects of white mineral trioxide aggregate

AIM

To assess the nociceptive and antinociceptive effects of white mineral trioxide aggregate (WMTA) using the orofacial formalin test in rats.

METHODOLOGY

Rats (n = 10 in each group) were separately injected into the ipsilateral upper lip with either 40 microL of a 2.5% formalin solution and eugenol (50 mg kg(-1)) or WMTA (5, 10 and 20 mg dissolved in 0.2 mL saline) alone. In a second experiment to evaluate antinociception effects, 15 min prior to formalin injection, rats were pre-treated with either white ProRoot MTA (20 mg dissolved in 0.2 mL saline) or eugenol. The time each rat spent rubbing the injected site with its paw, as an index of nociception, was recorded for a period of 45 min.

RESULTS

Administration of 40 microL white ProRoot MTA (5, 10 and 20 mg per 0.2 mL) alone did not produce any significant nociceptive response. Moreover, prior treatment with WMTA caused significant (P < 0.001) inhibition of formalin-induced nociception. Injection of eugenol (50 mg kg(-1)) provoked the first phase of a nociceptive response, although its intensity was reduced compared with that produced by formalin. Pre-treatment with eugenol significantly (P < 0.0001) inhibited the induction of nociception by formalin. Comparison of the behavioural responses observed in WMTA and eugenol-treated rats alone or in combination with formalin revealed that WMTA did not only induce pain behaviour but also prevented formalin-induced nociception.

CONCLUSION

White mineral trioxide aggregate, when compared with eugenol, was more effective in treating nociceptive pain in the orofacial formalin test.

Immediate and delayed solubility of mineral trioxide aggregate and Portland cement

This study investigated the solubility of mineral trioxide aggregate (MTA) and Portland cement since its mixture until 672 hours, by means of two complimentary methods. Metal ring molds filled with the cements were covered with distilled water and, at each experimental time (3, 24, 72, 168, 336 and 672 hours), were weighed as soon as the plates in which the samples have been placed. Empty rings served as the control group (n=8). Mean weight gain and loss was determined and analyzed statistically by two-way ANOVA and Tukey's test for all pairwise comparisons. Only Portland cement showed less than 3% weight loss through 24 hours. Detached MTA residues were heavier than those of Portland cement over the 3 to 168 hours. The weight of MTA rings increased more than that of Portland rings within 672 hours (p=0.05). The findings of the present study indicate that, in an aqueous environment MTA is more soluble than Portland cement and exceeds the maximum weight loss considered acceptable by ISO 6876 standard (2001).

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.

Bioactive materials in endodontics

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

The effect of a physiologic solution pH on properties of white mineral trioxide aggregate

The purpose of this study was to investigate the effect of two solutions differing by pH (6.4 and 4.0) and the use of a setting accelerator (15% Na(2)HPO(4) solution) on the properties of white-colored mineral trioxide aggregate (WMTA). These studies indicated that pH 4.0 had a deleterious effect on the morphology of WMTA mixed with water, however, not for WMTA mixed with Na(2)HPO(4). When immersed in a pH 4.0 solution for 7 days, WMTA mixed with water or Na(2)HPO(4) achieved a diametral tensile strength of 7.9 and 9.0 MPa, respectively, which was significantly lower (p < 0.05) than those obtained at pH 6.4 (11.2 and 12.0 MPa) but significantly higher (p < 0.05) than day 0 samples (4.4 and 4.8 MPa). Mixing WMTA with the accelerator did not significantly affect the microstructure, solubility, or strength in an acidic environment.

Histological, ultrastructural and quantitative investigations on the response of healthy human pulps to experimental capping with mineral trioxide aggregate: a randomized controlled trial

AIM

To investigate the pulpal response to direct pulp capping in healthy human teeth with mineral trioxide aggregate (MTA) as against calcium hydroxide cement (Dycal) as control.

METHODOLOGY

Twenty healthy human third molars had iatrogenic pulpotomy and direct pulp capping with MTA. Another 13 teeth were capped with Dycal as controls. The teeth were restored, with IRM, clinically reviewed and extracted after a number of pre-determined intervals (1 week, 1 month and 3 months). The specimens were fixed, decalcified, subdivided axially into two halves in the oro-buccal (lingual-buccal) plane, embedded in plastic, serial sectioned and evaluated qualitatively and quantitatively by correlative light and transmission electron microscopy with appropriate statistical evaluation of the quantitative data.

RESULTS

Iatrogenic pulpal wounds treated with MTA were mostly free from inflammation after 1 week and became covered with a compact, hard tissue barrier of steadily increasing length and thickness within 3 months following capping. Control teeth treated with Dycal revealed distinctly less consistent formation of a hard tissue barrier that had numerous tunnel defects. The presence of pulpal inflammation up to the longest observation period (3 months) after capping, was a common feature in Dycal specimens.

CONCLUSIONS

The MTA was clinically easier to use as a direct pulp-capping agent and resulted in less pulpal inflammation and more predictable hard tissue barrier formation than Dycal. Therefore, MTA or equivalent products should be the material of choice for direct pulp capping procedures instead of hard setting calcium hydroxide cements.

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.

Sealing ability of white and gray mineral trioxide aggregate mixed with distilled water and 0.12% chlorhexidine gluconate when used as root-end filling materials

This in vitro study used dye penetration to compare the sealing ability of white and gray mineral trioxide aggregate mixed with distilled water and 0.12% chlorhexidine gluconate when used as root-end filling materials. Ninety-six single-rooted human teeth were cleaned, shaped, and obturated with gutta-percha and AH26 root canal sealer. The apical 3 mm of each root was resected, and 3-mm deep root-end cavity preparations were made. The teeth were randomly divided into 4 experimental groups, each containing 20 teeth, and 2 negative and positive control groups, each containing 8 teeth. Root-end cavities in the experimental groups were filled with the experimental materials. After decoronation of the teeth and application of nail polish, the teeth were exposed to India ink for 72 hours and longitudinally sectioned, and the extent of dye penetration was measured with a stereomicroscope. Statistical analysis showed that there were no significant differences among the 4 experimental groups.

Apical capping as a new technique for retrograde treatment of an infected root apex: introduction and first results

INTRODUCTION

The success rate of surgical retrograde treatment of an infected root apex is limited by the existence of infected side canals which are not treatable by conventional retrograde preparation and filling techniques. This experimental study introduces a new technique of retrograde apex preparation followed by covering the apex with a titanium cap.

MATERIAL AND METHODS

In 10 extracted canines, retrograde circular preparation of the root apex was performed using a new ultrasonic preparation tip and a high-power ultrasound machine. The prepared stump was covered by a titanium cap fixed with glass ionomer cement. The teeth were examined clinically and radiologically for unevenness, steps or clefts in the border between the titanium cap and root surface. Furthermore, a histological work-up was performed to register the existence and number of side canals, as well as their covering by the titanium cap and the width of the cement layer.

RESULTS

The clinical and radiological examinations revealed only a small degree of unevenness in one case. In all other teeth the border was without any unevenness. There were 0 - 4 side canals as noted in the histological cross sections, all of which were covered by the titanium cap. The mean width of the cement layer was 27.2microm. From a technical point of view there were no difficulties or complications.

CLINICAL CASE REPORT

For demonstration of the clinical use, a case of a 32-old-patient with an apical cyst on an upper lateral incisor is reported. The patient was treated successfully by apical capping.

CONCLUSIONS

Apical capping is a new technique for retrograde treatment of an infected root apex which seals all side canals effectively. The technique is easy to perform and can be carried out quickly without complications. The technique is suitable for clinical testing.

Dens invaginatus in an immature maxillary lateral incisor: a case report of complex endodontic treatment

This case report presents the surgical endodontic treatment of an Oehlers Class II invaginated immature tooth. In this case, communication between the invagination and the pulp caused pulp necrosis, periapical inflammation, and cessation of root formation. The initial treatment goal was to achieve apexification and then fill both the root canal and the canal of the invagination. After a 6-month treatment with calcium hydroxide dressings, there was no healing radiographically and no sign of a hard tissue barrier in the apex. Periapical surgery with the placement of mineral trioxide aggregate (MTA) root-end filling was deemed successful at the 1-year recall. To treat dens invaginatus, both conventional and surgical endodontic treatment techniques should be considered. In dens invaginatus, conventional endodontic treatment modalities may be unsuccessful because of inadequate debridement and disinfection; however, subsequent periapical surgery and retrofilling with MTA may promote healing.

Long-term assessment of the seal provided by root-end filling materials in large cavities through capillary flow porometry

AIM

To evaluate the long-term sealing ability of a variety of materials when used as root-end fillings.

METHODOLOGY

A total of 140 standardized horizontal bovine root sections (external diameter: 7 mm, height: 3 mm; internal diameter: 2.5 mm) were divided into seven groups, filled with either gutta-percha with AH26, Ketac Fil, Fuji IX, Tooth-Colored MTA, IRM, Ketac Fil with conditioner or Fuji IX with conditioner and submitted to capillary flow porometry at 1 and 6 months to assess minimum, mean flow and maximum pore diameters. Results of the different materials and results by material were analysed statistically using non-parametric tests; the level of significance was set at 0.05.

RESULTS

There were no significant differences between the minimum pore diameters associated with the materials at each time. At 1 month the mean flow pore diameters of Ketac Fil were significantly larger than those of gutta-percha, Ketac Fil with conditioner, Fuji IX with conditioner and IRM. There were significant differences between the maximum pore diameters at 1 month (all>IRM; Fuji IX>gutta-percha, Ketac Fil with conditioner, Fuji IX with conditioner) and 6 months (Fuji IX>gutta-percha, IRM; Ketac Fil>gutta-percha, IRM). There were significant differences in the minimum pore diameters between the different points in time for each material except IRM, in the mean flow pore diameters for each material and in the maximum pore diameters for each material except MTA.

CONCLUSIONS

All materials were associated with capillary flow. IRM root-end fillings had through pores that were smaller than those associated with other materials. Conventionally setting glass-ionomer cements had the largest pores, although dentine conditioning improved their performance. The seal of all materials improved after 6 months.

Mineral trioxide aggregate pulpotomies

BACKGROUND

The greatest threats to developing teeth are dental caries and traumatic injury. A primary goal of all restorative treatment is to maintain pulp vitality so that normal root development or apexogenesis can occur. If pulpal exposure occurs, then a pulpotomy procedure aims to preserve pulp vitality to allow for normal root development. Historically, calcium hydroxide has been the material of choice for pulpotomy procedures. Recently, an alternative material called mineral trioxide aggregate (MTA) has demonstrated the ability to induce hard-tissue formation in pulpal tissue. The authors describe the clinical and radiographic outcome of a series of cases involving the use of MTA in pulpotomy procedures.

METHODS

Twenty-three cases in 18 patients were treated with MTA pulpotomy procedures in an endodontic private practice. All of the patients had been referred to the practice for diagnosis and treatment of a symptomatic tooth. All of the authors provided treatment. Pulpal exposures were either due to caries or complicated enamel dentin fractures.

RESULTS

Nineteen teeth in 14 patients were available for recall. The mean time of recall was 19.7 months. Of the 19 cases, 15 involved healed teeth, and three involved teeth that were healing. One of 19 cases involved a tooth with persistent disease.

CONCLUSIONS

MTA may be useful as a substitute for calcium hydroxide in pulpotomy procedures. Further research, however, is required to clarify this conclusion.

CLINICAL IMPLICATIONS

MTA conceivably could replace calcium hydroxide as the material of choice for pulpotomy procedures, if future research continues to show promising results.