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Showing 27 results for Dentin
Effect of Re-application of microbrush on micro tensile bond strength of an adhesive to dentin
Alireza Danesh Kazemi, Abdolrahim Davari, Seied Majid Mosavi Nasab, Ehsan Geravand,
Volume 25, Issue 4 (1-2013)
Abstract

Background and Aims: Re-application of microbrush may affect the micro tensile bond strength of adhesives to dentin. The aim of this study was to evaluate the effect of re-application of microbrushes on the micro tensile bond strength of an adhesive to dentin.

Materials and Methods: Thirty freshly extracted molars teeth were collected and enamel of occlusal surface were removed to expose superficial dentin. Then superficial dentin was etched, washed and partially air dried. According to the times of application of microbrush, teeth were divided into two test groups. In group 1, new microbrushs were used, but in group 2, the ones that were already used for twice were included. Ambar dentin bonding agent (FGM/Brazil) was applied to the etched dentin with microbrushes according to the manufacturer's instructions. Then the crown of teeth was built up with LLiss (FGM/Brazil) composite resin. The teeth were sectioned in buccolingual direction to obtain 1mm slabs. Then 50 hourglass- shape samples were made from 30 teeth (25 Specimens per group). The microtensile bond strength of the specimens was tested using MTD500 (SD Mechatronik, Germany). The data were statistically analyzed by T-test.

Results: The mean values for the microtensile bond strength were 30.49±7.18 and 23.61±9.06 MPa±SD for the first and second groups, respectively. There was significant difference between the groups (P=0.005).

Conclusion: Microbrushes should not be used for more than one cavity preparation.


Effect of different air-drying periods on microtensile bond strength of an adhesive to dentin
Alireza Daneshkazemi, Abdolrahim Davari, Majid Mousavinasab, Alireza Zahedifar,
Volume 26, Issue 2 (5-2013)
Abstract

Background and Aims: Today, use of adhesive systems is the most common materials in restorative dental procedures. The aim of this study was to evaluate the effect of different air-drying periods on the microtensile bond strength of composite to dentin using adhesive.

Materials and Methods: 15 sound molar teeth were selected. The an occlusal surfaces of teeth were removed with silicon carbide disks (3M/USA) to reach flat surface of dentin. Then according to the air drying of solvent, the teeth were divided to five groups. After 5 sec etching and rinsing for 15 sec , the teeth were air dried for 3 sec . Then Singlebond (3M) was used with different air-drying times (0s, 2s, 5s, 10s, 30s) and cured. Then after insertion and curing of Saremco (microhybrid low shrinkage/Switzerland) composite, the teeth were thermocycled for 500 cycles. Then hour glass slabs with 1 mm2 interface was created. Specimens were then subjected to µTBS force until fracture. Data were analyzed using ANOVA and Bonferroni tests.

Results: Statistical tests showed that there were significant differences between bond strength of groups (P=0.002). The mean of µTBS for the 2 Sec and 30 Sec evaporating time was the most and the least vawes, respectively.

Conclusion: An optimum air-drying time for solvent evaporation was the lowest time recommended by the manufacturer. Over and under evaporation time decreased µTBS significantly.


Investigation on the effect of two dual cure resin cements on the retention of fiber posts (in vitro)
Nina Rahshenas, Mohammad Hasan Salari, Maryam Koukabi Salehi, Mahshad Mohebbi,
Volume 29, Issue 1 (7-2016)
Abstract

Background and Aims: Debonding at the cement-dentine interface is the main reason of failure in restoration of endodentically treated teeth with fiber posts. The aim of this study was to compare the effect of Starfill 2B danville and Panavia F2 kuraray cements on the retention of fiber posts to root canal dentin.

Materials and Methods: Twenty extracted mandibular premolar teeth which had single root canal were endodentically treated and decoronated. Teeth were randomly divided into 2 groups, (n=40). Fiber posts were cemented using 2 dual cure resin cements. Group A was cemented with Starfill 2B Danville and group B was cemented with Panavia F2 Kuraray. Each root was mounted in acrylic resin and then sliced in 2 parts. The retention strength of each specimen was determined using push-out test using a universal testing machine. Data was analyzed using T-test.

Results: The retentive strength for groups A and B were 48.16±12.11 and 61.44±9.16 MPa, respectively. There was significant difference in the retentive strength between group A and B (P<0.05).

Conclusion: It seems that type of cement had effect on the retention of fiber posts. Panavia F2 Kuraray resin cement significantly provided higher retention than that of Starfill 2B Danville cement.


Effectiveness of a desensitizing dentifrice containing potassium nitrate 5% on cervical hypersensitivity of teeth: A randomized clinical trial
Zainab Kadkhoda, Sahar Rafiei Chokami, Azam Hosseini,
Volume 30, Issue 1 (6-2017)
Abstract

Background and Aims: Cervical tooth hypersensitivity (CTH) is defined as a sharp pain of short term that occurs in dentin exposed to the oral environment. The aim of this study was to evaluate the efficacy of a desensitizing toothpaste containing potassium nitrate (Sensodyne®) for relieving of CTH, when used locally or as tooth paste.

Materials and Methods: 36 patients were enrolled in this study. They were randomly divided into three groups I) Tooth brushing without toothpaste, II) Local application of toothpaste containing potassium nitrate 5%, III) Tooth brushing with toothpaste containing potassium nitrate 5%. Assessment of CTH was done by evaporative (using air and water spray) and cold stimuli at baseline, 1, 3, and six weeks after the treatment. To compare pain changes over time, due to the interaction between the variables of the studied groups and time, one-way ANOVA was used at any time. Due to the difference of variance between groups to compare pairs of groups, Dunnett T3 test was used.

Results: During the study period, no adverse event observed. In all three groups, pain decreased gradually. Local application of toothpaste had the most favorable effect on CTH. Therefore, when compared with that of the first group, the percentage reduction in pain were statistically significant (P=0.03).

Conclusion: Local application of toothpaste containing potassium nitrate as a desensitizing ingredient is a better choice for treatment of CTH than that of application with toothbrush.


Comparison of dentinal tubules closure under the effect of carbonated nano structural hydroxyapatite toothpaste produced inside the country with fluoride toothpaste
Rahelesadat Mirseifi Nejad Naini, Alireza Daneshkazemi, Fahime Shafiee,
Volume 31, Issue 2 (9-2018)
Abstract
Background and Aims: Increased tooth sensitivity is a common dental problem. One of the mechanisms of dentin hypersensitivity treatment is blocking dentinal tubules. The aim of this study was to compare the average closing dentinal tubules affected by carbonated Nano-hydroxyapatite and fluoride toothpaste using scanning electron microscope (SEM).
Materials and Methods: The enamel of gingival buccal crown surfaces of 42 sound maxillary premolars teeth were removed until the dentin surfaces were exposed. The dentine specimens of 3×3 mm were prepared. The specimens were washed by distilled water after etching and randomly divided into 6 groups. 3 groups were interfered with the carbonated nano-hydroxyapatite toothpaste and the other three groups interfered with Colgate toothpaste in 3, 7 and 14 days. The samples were examined by SEM to check the status of dentinal tubules. Then, they were evaluated by two researchers according to the Hulsmann index. Data were analyzed by using SPSS23 software and Kruskal-Wallis statistical test. The significance level of 0.05 was considered.
Results: The amount of dentinal tubules closure by the two toothpastes was significantly different. This difference was higher in the hydroxyapatite toothpaste than fluoride which were (P=0.024, 0.004 and 0.000), respectively. There were no significant differences among the groups in 3,7 and 14 days (P=0.230, 0.069, 0.537).
Conclusion: The toothpaste containing carbonated nano structural hydroxyapatite was more successful in closing dentinal tubules than Colgate toothpaste in short period of time.

Overview of recent advances in pulp/dentine complex tissue engineering
Parisa Noohi, Mohammad Jafar Abdekhodaie, Mohammad Hossein Nekoofar, Prof. Paul Mh Dummer,
Volume 36, Issue 0 (5-2023)
Abstract
Background and Aims: Pulp necrosis in immature teeth disrupts root development and makes the teeth susceptible to fracture. Regenerative endodontics is a relatively new modality of treatment where the necrotic pulp is replaced with newly formed healthy tissue which has normal functionality. Many clinical reports have demonstrated the potential of this strategy to induce root maturation and apical closure. However, clinical outcomes are patient-dependent and unpredictable. Developing predictable protocols can be achieved through the interplay of three basic elements of tissue engineering, namely, scaffolds, stem cells, and signaling molecules. Furthermore, the clinical success of this treatment is influenced by both the method of preparing the inner space of the root and the type of biomaterial utilized in the coronal part. In this review, we discuss recent advances in tissue engineering-based strategies for regeneration of the pulp/dentine complex along with their advantages and limitations. 

The effect of curcumin photosensitizer on bond strength of a universal adhesive to the caries-affected dentin
Maryam Saadat, Marzieh Moradian, Zahra Akbari, Parisa Ghodati,
Volume 37, Issue 0 (3-2024)
Abstract
Background and Aims: The bond strength of direct composite restoration to the caries affected dentin is a challenging issue. Preparation of dentin with an antibacterial agent is a method for creating durable bonded restorations. The aim of this study was to investigate the effect of curcumin photosensitizer on the bond strength of a universal adhesive to the caries-affected dentin (CAD).
Materials and Methods: In this experimental in vitro study, forty-four decayed human molar teeth were selected. After removing the surface enamel and dentin by a water-cooled saw, the decayed mid-coronal dentin was stained with a caries detection solution. The green and soft infected dentin was removed and CAD and hard and healthy surrounding dentin were left. Then, the remaining dentin surfaces were treated by 600 grit silicon carbide papers and polished. The specimens were divided into two groups (n=22): dentin pretreatment group by curcumin and control with no dentin pretreatment group by curcumin.  Each group was divided into two subgroups based on the method of application of All-Bond Universal adhesive (Bisco, USA) (etch and rinseand self-etching methods). After placing the Aelite All Purpose Body (Bisco, USA) composite, all  specimens  were placed in a universal testing machine for microshear bond strength (µSBS) test. The failure mode of the isolated surfaces was evaluated under a stereomicroscope. Two-way ANOVA analysis was used for statistical analysis.
Results: Based on the obtained results, intervention with the adhesive application method and surface pretreatment with curcumin had no significant effect on the bond strength. Also, there was no significant difference in the bond strength of the curcumin group in both etch and rinse and self-etching methods (SE=56.3±27.11 MPa; ER=52.4±84.11 MPa) (P=0.847). In the curcumin-free group, there was no significant difference between the two different adhesive application methods (P=0.187).
Conclusion: The results obtained in the present study showed that the pretreatment of dentin affected by caries with light-sensitive curcumin and also use of a universal adhesive by either self-etching or self-etchinf methodshad no influence on the microshear bond strength of the composite restoration.

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