Effect of MTA and Portland Cement on Fracture Resistance of Dentin.

Background and aims. It is important to evaluate the effects of endodontic materials on tooth structures to avoid endodontic treatment failure. The aim of the present study was to investigate the effect of mineral trioxide aggregates (MTA) and Portland cement (PC) on fracture resistance of dentin. Materials and methods. Thirty-six freshly extracted human single-rooted premolar teeth were selected. The crowns were removed and the roots were randomly divided into two experimental groups and one control group. The root samples were longitudinally divided into two halves and a dentin bar (2×2×10 mm) was cut from each root section for short-term (2weeks) and long-term (12 weeks) evaluations. The root sections in the experimental groups were exposed to MTA or PC, while keeping the control group specimens in physiologic saline. The fracture resistance of each specimen was measured using an Instron testing machine. The results were statistically analyzed using ANOVA, a post hoc Tukey test and paired t-test at 5% significance level. Results. The fracture resistance of MTA-treated specimens significantly increased between 2 and 12 weeks (P<0.05). After 12 weeks, MTA-treated specimens had the highest fracture resistance. In the PC group, the fracture resistance of specimens did not change significantly over time (P>0.05). Conclusion. The results showed that MTA increased the fracture resistance of root dentin, while PC had no significant effect on dentin fracture resistance.

Clinical and radiographic evaluation of vital pulp therapy in open apex teeth with MTA and ZOE.

The purpose of this study was to report the success rate of using mineral trioxide aggregate (MTA) and zinc oxide eugenol (ZOE) as vital pulp therapy agents in immature permanent teeth with carious or traumatic pulp exposure. Subjects were children with permanent teeth requiring pulpotomy (apexogenesis) and without systemic diseases. Both ZOE and MTA treatments as pulpotomy agents showed clinical and radiographic success in immature permanent teeth. Although MTA was more successful, it is more expensive, and dentin bridges may develop over canal orifices, complicating future root canal therapy.

Comparison of tooth crown discoloration with Epiphany and AH26 sealer in terms of chroma and value: an in vitro study

Tooth crown discoloration may possess a heavy emotional burden and esthetic concern, especially when the anterior teeth are affected. Residue of sealers within the pulp chamber is a major contributor to the occurrence of tooth discoloration. Aim: The aim of this study was to evaluate the degree of crown discoloration when recently introduced sealer, Epiphany, is used. Methods: Forty human incisors were examined in vitro. Fifteen teeth were sealed with either AH26 or Epiphany sealer as experimental groups and root canals of the remaining 10 teeth with distilled water. Digital photographs of the buccal aspect of teeth were then examined in terms of brightness (value) and saturation (chroma) using Photoshop software at the beginning and consecutive 3, 6 and 9 months. Degree of brightness and saturation changes was defined as follows: less than 5% as slight, 10% to 15% as moderate and 15% to 20% as severe. Results: Fifteen, 14 and 10 teeth entered in Epiphany, AH26 and control groups, respectively. Significant brightness deterioration was noticed by time in both experimental groups [F (2, 8) =29.16, p<0.001], with no differences in Epiphany compared with AH26 (p=0.086). Saturation differed neither by time [F (2, 8) =0.129, p=0.881, nor by sealer type (p=0.136) during 9-month observation. At 9th month, crown segments (incisal, middle and cervical thirds) were not contrasted by the sealer type (p=0.982) or discoloration type (either brightness or saturation) (p=0.50). All changes in the experimental groups were significantly higher than the control group (p<0.001). Conclusions: Epiphany was equal to AH26 sealer in terms of relative long-term crown discoloration. One clinical correlation learned from the results of the present study is that Epiphany may safely be used interchangeably with the traditional AH26 sealer.

Comparison between gutta-percha and Resilon retreatment.

Retreatment procedures in endodontic practice require complete removal of the original root filling materials. The aim of this study was to compare the amount of residual filling material on the walls of root canals that were obturated with gutta-percha or Resilon. Thirty extracted single-rooted human teeth were selected and instrumented by RaCe rotary instruments up to MAF #35. They were randomly divided into two groups of 15 teeth each. Group 1 was obturated with gutta-percha and AH26 sealer and group 2 was obturated with the Resilon/Epiphany system by lateral condensation technique. All canals were then retreated using Gates-Glidden drills, MAF #40 and chloroform. The teeth were split longitudinally and photographs were taken by a digital camera connected to a stereomicroscope and then samples were analyzed. The amount of residual material and time of retreatment were determined in each group at three levels in the canal. Data were analyzed by Mann-Whitney and Friedman tests. The Resilon group had significantly more residual material in the canal than the Gutta-percha group (P = 0.009). According to the level of the canal, the differences were statistically significant (P = 0.013) only in the Resilon group. Time required for retreatment in the two groups was not significantly different (P = 0.381). Orthograde retreatment of Resilon was less efficient than that of gutta-percha.

Simulated root resorption: a new study model.

INTRODUCTION: The aim of this innovative study was to regenerate a condition that makes it possible to carry out researches in the field on a variety of resorption. MATERIALS AND METHODS: In order to develop apical resorption, the root canals of selected teeth were instrumented and then drilled with #4 Gates Glidden drills. In the next stage, the teeth were submerged in melted rose wax up to 3 mm to the apex. The waxed teeth were submerged in 20% sulfuric acid for 4 days. After that, all samples were evaluated under stereomicroscope and also the SEM. RESULTS: Images showed areas with different pattern of resorption in root apex and entire root canals in all samples. CONCLUSION: Simulation of the root resorption can be helpful in many experimental studies.

Clinical and radiographic evaluation of root perforation repair using MTA.

An accident that can occur during endodontic treatment is perforation, which adversely affects the prognosis of the teeth. A restorative material should be easy to use, nonresorbable, biocompatible, esthetically pleasing, and should provide a complete seal. Mineral trioxide aggregate (MTA) is a relatively new material that is being used successfully to repair perforation. The purpose of this study was to perform a clinical and radiographical evaluation of the success rate of root perforation repairs using mineral trioxide aggregate. Based upon the results of this study, MTA is a suitable material for root perforation repair and can be used confidently.

Evaluation of Adhesion and Morphology of Human Osteoblasts to White MTA and Portland Cement.

INTRODUCTION: Osteoblasts and periodontal ligament cells are major cells for wound healing after root end resection. The interaction of osteoblasts with filling materials could play a critical role in healing of surgical lesion. Adhesion and spreading of cells on material surface are the initial phase for cellular function. The purpose of the present study was the evaluation of morphology and attachment of human osteoblasts in present of white MTA, Portland cement (PC) and IRM as root end filling and perforation repair materials. MATERIALS AND METHODS: The human osteoblasts (MG-63 cell line) were prepared from Iranian Pasteur Institute; Cellular Bank, were grown in RPMI 1640 medium. The testing materials were mixed according to the manufacture's instruction, inserted in to the wells of 24-well flat-bottomed plate, and condensed to disk of 1mm thickness and 1×1mm diameter. Cells were added to the materials after two weeks. During 1,3,7 days intervals, the disk of materials along with cells were grown on their surface, examined by a scanning electron microscope (SEM). We used of IRM as negative group. RESULTS: Results showed that after 7 days many of osteoblasts were attached on the surface of white MTA and PC and appeared partially round or flat. The cells appeared round with no attachment and spreading in conjunction with IRM. CONCLUSION: The results indicate that human osteoblasts have a favorable response to white MTA and Portland cement compared with IRM.