فهرست مطالب

  • Volume:30 Issue: 1, 2018
  • تاریخ انتشار: 1397/01/18
  • تعداد عناوین: 6
|
  • Samaneh Doustfateme, Kazem Khosravi, Somayeh Hosseini * Pages 1-8
    Comparative Evaluation of microleakage of Bulk-fill and Posterior Composite Resins Using the Incremental Technique and a Liner in Cl II Restorations Abstract
    Background And Aim
    I recent years there has been a surge in the use of tooth-colored restorations. However, the polymerization shrinkage of these materials can form gaps, resulting in microleakage. This study aimed to compare microleakage by using different materials and techniques.
    Materials And Methods
    In this experimental study, Cl II cavities were prepared on the mesial surfaces of 60 sound human third molars. The teeth were randomly divided into five groups (n=12): Group 1 were filled with Surefil posterior composite using the oblique incremental technique. In group 2 Surefil SDR flowable composite was placed at the base of cavities followed by filling the cavity with Surefil posterior composite. Specimens in group 3 were restored only with Surefil SDR flowable composite resin in two steps, and in group 4, a layer of G-aenial Universal flow composite with 1 mm thickness was placed as the liner and the rest of the cavity filled with the Surefil posterior composite using the oblique incremental technique. Group5 benefited from snow plow technique using G-aenial Universal flow and Surefil posterior composite. Samples thermocycled and placed in 0.5% fuchsine solution for 24 hours. The teeth were evaluated under a stereomicroscope for the deepest dye penetration. Kruskal-Wallis and Mann-Whitney tests were used for analysis of data.
    Results
    The highest frequencies of scores 1 and zero were recorded in the group 5 which indicating the least microleakage in this group.
    Conclusion
    G-aenial Universal Flo composite resin with the snow plow technique resulted in a significant decrease in the microleakage.
    Keywords: Composite Resins, Dental leakage, Dental Cavity Lining, Polymerization
  • Haleh Heshmat, Mohammad Hossein Jahangiri, Maryam Hoorizad Ganjkar, Mansoureh Emami Arjomand *, Mohammad Javad Kharazifard Pages 9-14
    Background And Aim
    Recurrent caries and low bond strength are the main causes of composite restorations failure. This study sought to assess the effect of chlorhexidine (CHX) on micro-shear bond strength (MSBS) to dentin of a fourth generation adhesive system and a universal bonding agent after aging.
    Materials And Methods
    This in vitro study used 32 extracted third molars and 3-5mm thick dentin slices were cut out of each tooth. Specimens were randomly divided into 8 groups. After etching, Scotchbond fourth generation bonding agent or Single Bond universal adhesive was applied on dentin surfaces and Z250 composite cylinders were bonded to the surfaces. In groups B, D, F and H, CHX was applied for 1 minute after etching and prior to the application of bonding agent. The MSBS was measured after 24 hours and four months of water storage at 37C using a micro-tensile tester. The collected data were analyzed using three-way ANOVA.
    Results
    The Scotchbond yielded significantly higher MSBS than the universal adhesive at 24 hours and four months (P
    Conclusion
    The MSBS of Scotchbond fourth generation bonding agent was generally higher than that of Single Bond universal adhesive. The MSBS of both adhesives decreased over time, however, the application of CHX decelerated the deterioration rate.
    Keywords: Adhesives, Chlorhexidine, Shear Strength
  • Sohrab Tour Savadkouhi, Ehsan Esnaashari *, Reyhaneh Dowlatabadi, Keivan Saati, Mohammad Javad Kharazifard Pages 15-20
    Background And Aim
    Tooth discoloration induced by endodontic materials is a common finding which can impair the aesthetic outcome. The aim of this study was to compare the coronal discoloration induced by Well-Root ST and AH26 root canal sealers by using the Easyshade® colorimeter.
    Materials And Methods
    Forty-five intact maxillary central incisors were involved in this experimental study. The prepared specimens were randomly distributed in experimental and control groups as follows: group 1 (Well-Root ST, n=15), group 2 (AH26, n=15), positive control group (amalgam, n=5), negative control group1 (gutta-percha, n=5), and negative control group 2 (distilled water, n=5). In order to evaluate the discoloration rate (ΔE), The Easyshade® spectrophotometer was used at one and six months post-obturation. Analysis of variance (ANOVA) was used to com-pare color changes in the groups at the mentioned time intervals.
    Results
    The difference between the experimental groups (Well-Root ST and AH26) and the negative control groups was not statistically significant (P=0.99) at one and six months after obturation. However, the difference between the experimental groups and the positive control group was significant (P=0.000). The difference between the positive control group and the negative control groups was also significant (P=0.000).
    Conclusion
    The results of the current study indicate that both experimental sealers (Well-Root ST and AH26) have minimal discoloration effects and can be used safely in the aesthetic zone.
    Keywords: Tooth Discoloration, Root Canal Filling Materials, Esthetics, Dental
  • Mansoreh Mirzaie, Aiob Pahlavan, Tabassom Hooshmand, Hoda Safaee, Reihaneh Khalesi Tooyrekani * Pages 21-31
    Background And Aim
    Color match between prosthetic restorations and natural teeth is challenging in dentistry. The aim of the current study was to assess the effect of accelerated aging on color stability of two silica-based ceramics with leucite and lithium disilicate crystalline phases after glazing and polishing surface treatments.
    Materials And Methods
    In this experimental study, 30 disc-shaped specimens (1.5x10mm) of IPS e.max Press and Ceramco III ceramics were fabricated according to the manufacturers’ instructions. The specimens were randomly divided into two groups of surface treatments (glazing and polishing) and were then subjected to accelerated aging for 300 hours. Color parameters were measured before and after aging using a spectrophotometer. The L*, a* and b* parameters and the color change (∆E) of ceram-ics (based on the CIE L*a*b* system) before and after glazing were determined by spectrophotometry. Data were analyzed using two-way ANOVA and t-test. P
    Results
    After 300 hours of aging, the color stability (∆E), ∆L and ∆b of polished group was less than that of glazed group. The two ceramic types were not significantly different in terms of ∆E (range: 1.31 to 2.53; P=0.055).
    Conclusion
    Glazed silica-based ceramics had higher color stability than polished ceramics after aging in our study. Color stability of silica-based ceramic systems was influenced by the surface texture and not the type of crystalline phase.
    Keywords: Lithia Disilicate, Aging, Discoloration
  • Shima Safaeian, Sareh Habibzadeh *, Seyed Jalal Porhashemi, Niloofar Entezari Moghaddam Pages 32-38
    Background And Aim
    There is a gap of information on the effect of time, disinfectant, and storage conditions on the dimensional stability of direct post patterns made of self-cure acrylic resins. This study assessed the effect of Deconex® and wet or dry stor-age conditions on the dimensional stability of post patterns made of Duralay and GC acrylic resins.
    Materials And Methods
    Sixty specimens were fabricated of GC and Duralay acrylic resins (n=30) by using a stainless steel mold. The specimens in each group were divided into three subgroups (n=10). The specimens of subgroup 1 were immersed in Deconex® for 2 minutes followed by dry storage at 25°C. The specimens of subgroup 2 were stored in water at 25°C. The samples of subgroup 3 were immersed in Deconex® for 2 minutes followed by water storage at 25°C. The dimensions were measured immediately and 2 minutes, 1 hour, and 24 hours after setting. Data were analyzed by repeated measures ANOVA. One-way ANOVA and t-test were used for subgroup analysis at 5% significance level.
    Results
    The greatest mean dimensional changes occurred after 24 hours in both groups. In GC group, subgroup 1 experienced minimal changes during 24 hours. Duralay subgroups 1 and 2 experienced minimal changes after 1 and 24 hours; the difference between the two subgroups was not significant. Maximum changes were noted in GC subgroups 2 and 3 and in Duralay subgroup 3 (P
    Conclusion
    In case of a 24-hour delay, storage conditions would have no effect on the dimensional stability of Duralay patterns, while GC patterns should be stored in a dry condition.
    Keywords: Acrylic Resins, Dental Dowel, Post, Core Technique, Disinfection
  • Bahman Seraj, Mona Sohrabi *, Maryam Shafizadeh Pages 39-43
    Introduction
    Revascularization is the newest treatment proposed for an immature permanent tooth with necrotic pulp. Revascularization is defined as a treatment process with a biological base which is aimed at replacing the lost structures and the continued development of roots.
    Case Presentation
    Patient was an eight-year-old child with the history of trauma to the maxillary anterior region. After clinical and radiographic evaluations, tooth #9 was diagnosed with the pulp necrosis, and revascularization was carried out according to Banch and Trope principles.
    Conclusion
    The clinical and radiographic evaluation after treatment revealed no signs and symptoms and root development was in progress which was an indication of successful treatment. It seems that, in the case of proper selection of the patient, this method can be an appropriate replacement for apexification in immature teeth with pulp necrosis.
    Keywords: Necrosis, Dental Pulp, Regeneration, Apexification