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Showing 4 results for Malekzadeh
Evaluation of the effect of patient’s age on the tooth response to electric pulp test
Jalil Modaresi, Vahid Shirani, Mohammad Malekzadeh,
Volume 27, Issue 2 (6-2014)
Abstract

  Background and Aims: Electric pulp tester is a valuable instrument to examine tooth’s pulp vitality. There is no agreement about the response of immature teeth to electric pulp tester and the reason is expressed as the failure of nerve fibers’ development. The aim of this study was to investigate the effect of patient’s age on the tooth response to electric pulp tester.

  Materials and Methods: In this cross-sectional study, 300 maxillary central permanent teeth in 150 volunteers were examined by using electric pulp tester. The volunteers were classified in 5 age groups of 7-8, 9-10, 11-12, 13-4, and 30-35 and teeth lacking sound and healthy pulp were excluded. Data were analyzed using SPSS-16 software, one-way analysis of variance, and Tukey post hoc test.

  Results: The average response to electric pulp tester in age groups of 7-8, 9-10, 11-12, 13-4, and 30-35 years old were 2.9±0.1, 2.8±0.1, 2.3±0.1, 2.2±0.1 and 1.8±0.1 ,respectively. This indicated that by increasing teeth age, they responded to lower level of electric pulp tester. In subjects less than 14 years old, there was no significant difference between neighboring groups (P=0.3) however, a significant difference was observed between subjects less than 14 years old and adults (P<0.001).

  Conclusion: This study showed that immature teeth responded at higher levels to electric test however, all teeth responded to electric pulp tester.


Marginal microleakage of class V composite restorations before and after AFP gel application
Davari Abdolrahim , Daneshkazemi Alireza , Modaber Maryam , Malekzadeh Mohammad ,
Volume 27, Issue 4 (1-2015)
Abstract

  Background and Aims: The most effective preventing tooth decay method is fluoride compounds applications. Some studies suggested that APF gels caused changes on the superficial physical properties of composite. Therefore, the purpose of this study was to evaluate the marginal microleakage of class V composite restorations before and after AFP gel application.

  Materials and Methods: The class V cavities in buccal surfaces of 45 molar teeth were made in such a way that occlusal margin was placed in enamel and cervical margin in cement. In group 1, at first fluoride-therapy and then cavity preparation and restoration by composite resin was done. In group 2, at first the class V cavities were prepared and restored, then fluoride-therapy was carried out. In group 3, cavities were prepared and restored with no fluoride-therapy. The dye penetration rate in occlusal and cervical margins was examined by stereomicroscope. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney test.

  Results: There was no statistically significant difference between groups ( P=0.975).

  Conclusion: Fluoride-therapy using AFP gel before and after class V composite restorations, had no significant effect on the microleakage of dentin and enamel margins.


The effect of Sandblasting and Laser surface treatment on shear bond strength between zirconia and porcelain veneer
Mohammad Hosain Lotfi Kamran, Mahnaz Hatami, Abbas Fallah Tafti, Mohammad Malekzadeh,
Volume 30, Issue 3 (10-2017)
Abstract
Background and Aims: To create a good adhesion between porcelain veneers and zirconia restorations has been important issues is the prosthesis. The aim of this study was to identify an effective way to prepare the zirconia surface infrastructure to increase its shear bond strength to the porcelain veneer.
Materials and Methods: 75 samples of zirconia (Y-TZP) cylinders (diameter of 7 mm and a thickness of 3 mm) were fabricated. Based on the surface treatment, specimens were randomly divided into 3 groups: control, air abrasion and
Er-YAG laser. After surface treatment, the specimen surfaces were examined by SEM. Using a metal mold, the porcelain was veneered on the zirconia surface and then fired. After thermocycling, the shear bond strength of porcelain to zirconia was measured and then the failure mode of each specimen was analyzed using a stereo-microscope. Data were analyzed by one-way ANOVA and Tukey test.
Results: Significant differences were observed between the mean shear bond strength of different groups (P=0.001). The greatest amount of shear bond strength was observed in the group (S) and the lowest bond strength in the control group. Analysis of failure modes showed no statistically significant difference in the type of failure among study groups. The adhesive failure was predominating failure at the intersection of porcelain veneers.
Conclusion: The highest shear bond strength between zirconia and porcelain was achieved by sandblasting the zirconia surfaces compare with that of Er_YAG application.

Effect of changing the horizontal angle of periapical X- ray radiation on detection of secondary caries under class II amalgam restorations:In vitro
Mehrafruz Daneshian, Kianoosh Malekzadeh, Masoomeh Afsa,
Volume 35, Issue 0 (5-2022)
Abstract
Background and Aims: Achieving non-invasive methods for the proper detection of secondary caries adjacent to dental restorations has a great importance. As alterations in horizontal and vertical angles of X-ray beam would affect the detection of dental caries on radiographs, this study was designed to evaluate the effect of changing the horizontal angle of X- ray on detection of dental caries adjacent to class II amalgam restorations in posterior teeth on periapical radiographs.
Materials and Methods: In this in vitro study, artificial carious lesions were prepared in axial walls of the amalgam restoration cavities in interproximal surfaces of 27 human extracted premolar teeth. Periapical radiographies with different horizontal X- ray angles were obtained, observed, and rated by 5 maxillofacial radiologists for detection of carious lesions. For each observer, the sensitivity, specificity, accuracy, PPV, and NPV of radiographs in the individual horizontal angles were calculated and compared by nonparametric Kruskal Wallis test. Interobserver agreement was assessed by fleiss’ kappa coefficient.
Results: The highest accuracy of periapical radiographs for the detection of secondary caries of mesial dental surfaces was in 5-degree of mesial and distal X- ray angle (86.66%) and for the distal dental surfaces was allocated to 10-degree of distal X- ray angle (85.90%). Also, there was a significant difference in the accuracy between different horizontal angles (mesial and distal 0, 5, 10, 15-degree) (P=0.01). The higher agreement between observers in detecting mesial surface caries was in 10-degree of distal angle (0.86) and in detecting distal caries was in 5-degree of distal angle (0.89).
Conclusion: In the case of doubt in the existence of recurrent caries in the interproximal tooth surface, if the carious lesion is not visible on standard radiographic image with direct angle of X- ray, A 5- 10 degree of x- ray horizontal angle can improve the detection of secondary caries under amalgam restorations in interproximal dental surfaces.

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