Showing 6 results for Rohani
M. Ghavam-Nasiri , F. Malek-Nejad , A. Rohani , M. Akbari ,
Volume 16, Issue 2 (8 2003)
Abstract
Statement of Problem: A lot of efforts have been made to create a complete adaptation between tooth and amalgam restorations.
Purpose: The aim of this study was to evaluate microleakage and interfacial micromorphology of amalgam restorations lined with dentin adhesives, namely One Coat Bond, Syntac, Excite and Copalite,as liners.
Materials and Methods: 144 intact human canine teeth were selected. Then class V cavities, with enamel and dentinal margins, were prepared on each of them. Cavities were lined with different dentin bonding systems (Syntac, One Coat Bond and Excite) according to the manufacturer's instructions and restored with Oralloy and Cinalloy, non gamma 2 spherical amalgams and Aristaloy a non gamma 2 Admixed alloy. Copalite was used in the group, served as controls. After thirty days storage in synthetic saliva at 37°c, the specimens were thermocycled in saliva (4000 cycles). The degree of microleakage was assessed by means of basic fushin dye penetration and recorded. The gap width was evaluated with Scanning Electron Microscope. Pearson and %2 tests were used to analyze the results.
Results: None of the systems, tested in this study, eliminated microleakage completely, Pearson's correlation coefficient showed a positive correlation between gap and microleakage (P<0/05).Statistical significant differences were revealed among the liners regarding gap and microleakage (P<0.05).One Coat Bond and Syntac appeared to leak less than other groups. The gap width by One Coat Bond and Syntac were respectively 0.35 and 0.3 urn in dentine, 0.2 and 0.1 in enamel. Excite and copalite gap width in dentine and enamel were 1,3-1.36 urn and 0.3-0.6, respectively. The type of amalgam did not have any effect in the degree of microleakage and gap width (P>0/05).
Conclusion: One Coat Bond and Syntac, comparing to Excite and Copalite, showed less microleakage and gap width.
A. Rohanian, Gh. Ommati Shabestari,
Volume 23, Issue 1 (22 2010)
Abstract
Microstomia is defined as an abnormally small oral orifice. Microstomia can occur as a result of trauma from electrical and thermal lesions, chemical burns and trauma from surgeries. Prosthetic rehabilitation of microstomia patients presents difficulties at all stages, from the preliminary impressions to fabrication of prosthesis. For impression procedures different treatment methods have been suggested. Swing hinge and collapsible dentures are used to provide prosthodontic treatment to patients with microstomia. Not only is such a prosthesis difficult to fabricate, but may be expensive. The literature contains reports on the fabrication of sectional denture with the denture pieces connected by different designs. This article describes a simple method of fabricating a 2-pieces denture using removeable partial denture metal framework to connect the sections, for a patient with limited oral opening. Combination of metal framework and sectional complete denture for a patient with limited oral opening is an acceptable, effective and available method.
Mahmod Kazemi, Saeed Nokar, Ahmad Rohanian, Adel Pazhohan,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: Thermal changes in the oral cavity can be transferred to the implants placed in bone and affect the prognosis of the treatments. Furthermore, some investigators proposed improvement of habitual consumption of hot or cold beverages. The aim of the present study was to measure the effect of temperature changes in the oral cavity following consumption of hot and cold drinks on the temperature of implant.
Materials and Methods: In this clinical trial, 3 eligible patients were selected. Two months after implant insertion, temperature of the implants was measured following the drinking of hot and cold beverages using a sensor connected to a thermometer. The thermal changes of the implants through the different time intervals were analyzed using Friedman non-parametric test.
Results: The implant temperatures were significantly increased in the time following drinking of the hot beverages (P=0.009). Furthermore, the implant temperature were statistically decreased in the time after drinking cold beverage (P=0.004). When drinking hot beverages, the maximum and minimum temperatures were 41.57 0 C and 36.77 0 C, respectively. The maximum and minimum temperatures of the implants were also 34.13 0 C and 26.83 0 C , respectively, when drinking cold beverages.
Conclusion: It seems that the temperatures noted in the implants in the current study cannot weaken the prognosis of implant restorations however, habitual consumption of hot and cold beverages can lead to debilitating implant prognosis and therefore, should be given the necessary warnings to patients.
Saeed Nokar, Amir Azizi, Ahmad Rohanian,
Volume 27, Issue 1 (4-2014)
Abstract
Background and Aims: Nowadays, the application of all ceramic restorations are being raised, because of their physical characteristics, such as translucency and good appearance. Numerous researchers investigated the impact of surface treatments on the bond strength of zirconia ceramic with resin cements. The aim of this study was to compare the microshear bond strength of Cercon and Zirkonzahn (two kind of zirconia) ceramics, to two types of resin cements after thermocycling.
Materials and Methods: In this study, 24 rectangular specimens were made from each group of Cercon and Zirkonzahn ceramics. After sandblasting, these specimens were connected to 3×1 mm2 composite cylinders by two resin cements (Panavia F2 and Rely X Unicem2). After performing a thermocycling regime for 5000 cycles (5-55 ◦ C), the microshear bond strengths were measured by a universal testing machine. The mode of failures were determined by a stereomicroscope. Data were analyzed using two-way ANOVA.
Results: Type of ceramics had no significant impact on the microshear bond strength (P=0.317). The highest bond strengths in both ceramics were obtained with Reply X Unicem (P=0.035). The predominant failure mode was adhesive between the cement and ceramic.
Conclusion: Type of resin cement had a significant effect on their bond strengths to zirconia ceramics.
Alireza Hashemi Ashtiani, Ali Rohani, Sara Kholghi,
Volume 31, Issue 1 (6-2018)
Abstract
Background and Aims: Wear resistance of artificial teeth has an important role in denture longevity. The purpose of this in vitro study was to evaluate the wear resistance of three types of composite resin denture teeth with that of acrylic resin.
Materials and Methods: In this study, four types of artificial teeth, including 3 types of composite artificial teeth (Ivoclar, Apple and Yamahachita) and 1 type of acrylic resin artificial teeth (Ivoclar) were used. Ten maxillary first premolars were selected from each set and were fixed in autopolymerising acrylic resin. The wear test was performed for 1000 and 2000 cycles. The heights and weights were measured under a light stereo microscope and scales (0.001 gram accuracy) before and after wear cycles. Data were analysed by ANOVA and Duncan tests (P=0.05).
Results: There was no significant difference between the mean wear of the composite and acrylic resin ivoclar artificial teeth in 1000 and 2000 cycles (P>0.05), but this difference was significant between the other artificial teeth (P<0.05). In 1000 and 2000 cycles, there was a significant difference between the mean weight loss of samples of all four artificial teeth groups (P<0.05). Also, in this study, the composite and acrylic ivoclar artificial teeth showed significantly less wear-resistant than that of other teeth, and the highest wear rate was found for Yamahachita's composite artificial teeth.
Conclusion: The findings of this study suggested that Ivoclar composite or acrylic resin denture teeth can be more suitable options than other artificial teeth used in this study in cases susceptible to abrasion.
Mohammad Javad Moghadas, Ehsan Rohani, Sara Majidinia, Najmeh Ojrati, Negin Vatanparast,
Volume 31, Issue 4 (1-2019)
Abstract
Background and Aims: The aim of the present study was to evaluate the effect of applying hydrophobic resin after use of different generation of the bonding systems on nanoleakage.
Materials and Methods: 20 third molar teeth were selected. The teeth were randomly divided into 4 groups of 5, each was treated using the fourth, fifth, sixth, and seven generation of dentin bonding. Then, the crown of teeth was sectioned from the CEJ region and each specimen was divided into two halves with mesiodistal cut, one half for the application of dentin bonding without the addition of a hydrophobic resin, and the other for the same dentin bonding by the addition of a hydrophobic resin. Afterwards, the specimens were restotred by composites. After placement of specimens in silver nitrate, the amount of nanoleakage was evaluated by SEM. Data were analyzed using a repeated measurement statistical analysis (α=0.05).
Results: The use of hydrophobic resins decreased nanoleakage and range of variations in all groups (P<0.05). This reduction was greater for total-etch dentin bonding. Higher degree of nanoleakage occurred in total-etch dentin bonding in most evaluated areas. In general, Clearfil S³ bond showed the least percent of the nanoleakage.
Conclusion: All dentin bonding systems showed some degree of reduction in nanoleakage after hydrophobic layer application and the reduction was greater in Total-etch adhesives systems.
