Showing 11 results for Rokn
Ar. Rokn , M. Paknezhad,
Volume 9, Issue 2 (9 1996)
Abstract
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AR-SA In a 2 year study, indices of implant health
such as PPD, PAL, BI and GI were measured and compared at the baseline, 6
months, 1 and 2 years after implant delivery.
It was found that PPD and PAL
indices were decreased in second year in compare to the first year which
implicates success and health of implant in a 2 year period following
prosthesis insertion.
Ar. Rokn , F. Geramipanah ,
Volume 11, Issue 1 (7 1998)
Abstract
A 48 year old patient was candidate for anterior mandibular reconstruction by 2 fixtures of Branemark implant. Residual infection lead to removal of one of the implants from the extracted tooth socket. Afterwards, 2 fixtures of Bonefit was inserted adjacent to previously placed Branemark implants and final prosthesis were loaded in a joint cemented and screwed design.
Ar. Rokn , E. Tabatabaei ,
Volume 12, Issue 2 (9 1999)
Abstract
This study is for appointment the dose of systemic 4 groups of patients selected for this study.First group had sealling, root planing and planing and periodontal surgery and no drugs. Second group had sealling, root planing and periodontal surgery with 1 gr per day of tetracycline for two weeks and third group for 3 weeks and fourth group for 4 weeks.The fourth group was.the best clinical improvement. The indexes were PPD, CAL, PI, GI.
M. Pak Nejad, Am. Rokn , H. Semyari ,
Volume 14, Issue 3 (9 2001)
Abstract
The aim of the present study was the histological evaluation of Enamel Matrix Derivative (EMD) effectiveness for regeneration of periodontal defects. EMD activates cementum synthesis, PDL and bone during the maturation stage of follicole. In this research, EMD was used in surgical defects of premolar teeth in four adult sheep. Muccoperiosteal flap was reflected in buccal site of teeth. The buccal bone plate was removed from mesial to distal in 4 mm depth. After eliminating the cementum by bur and its etching, EMD was applied on exposed dentine and flap was sutured. In opposite sites of those teeth (control sites) the same process was performed without etching. After 100 days, sheep were sacrificed and histological study through light microscopic was performed on black sections of operation sites. The results showed that in test sites, regeneration of cementum and bone was 62/5% and 42/5-50% respectively. But in control sites regeneration of cementum and bone was 37.5% and 32/5-42/5% respectively. Also the migration of junctional epithelium in control sites was 8-10% more than test sites. The important point is that in test sites, cementum was completely attached to undermining dentine. But, in control sites, the gap between cementum and dentine was visible. As a result, this study suggests that EMD promotes periodontal regeneration, and EMD application is a successful achievement in regenerative periodontal therapy.
Sa. Miremadi , Ar. Rokn , A. Nikbakht ,
Volume 15, Issue 4 (9 2003)
Abstract
In the past two decades, replacement of the missing teeth with implant borne prosthesis has become a treatment modality, accepted by the scientific community for fully and partially edentulous patients. The aim of the present study is to evaluate retrospectively, 502 ITI dental implants application, in partial and complete edentulous patients, treated in two private centers, based on clinical and radiographic parameters.One hundred and forty patients, with 502 ITI dental implants, who were treated from 1994 to 2000 in two private centers, were investigated. For such patientsT a minimum of one year and a maximum of six years were passed since prosthesis placement over implants, so they were cooperative subjects. There was a significant relation between implant type and bone loss, so was between the presence and absence of BOP and the rate of bone loss. From totality 502 implants, 6 implants (28%) and 4 implants (1.4%) were lost, in maxilla and mandible, respectively. The total success rate was 98%. This rate, in maxilla with 212 implants was 97.2% and in mandible with 90 implants was 98.6%. The mean value of bone loss (RBL) and periodontal pocket depth (PPD) during 6 years, for the remaning 492 implants were 0.93±0.39mm and 1.99mm, respectively. The results showed that ITI dental implants, with a success rate of more than 97%, can be used as a desirable treatment choice in partial and complete edentulous patients.
Ar Rokne , M. Paknejad , B. Eslami , A . Safiri ,
Volume 16, Issue 3 (10 2003)
Abstract
Statement of Problem: The goal of bone regenerative therapy is to reconstruct the damaged tissues to initial condition, which seems so important in periodontoiogy and implantology. In such therapies, different biomaterials, with some advantages and disadvantages, may by use.
Purpose: The aim of this research was to evaluate the quality, bone trabecular density and thickness of newly forming bone as well as foreign body reaction against Biostite®, in comparison with the control group.
Material and Methods: In this experimental study the total number of 5 sheep was operated with general anesthesia. At first 10 standard defects were created in 5x5x5mm on the left and right edentulous mandibular ridge. Five defects were randomly treated by Biostite®, the remaining five were considered as controls. After six months, the sheep were sacrificed and the separated defect areas with intact margin
were placed in 10% formaline and prepared for histologic and histomorphometric study. To analyze the data, Mann-Whitney U test was used.
Results: The mean percentage of new bone formation in Biostite® group was statistically more than the control group (PO.05). Newly formed bone was vital in both groups which was a combination of lamellar and woven types, however, the thickness and density of new bone in biostite® group was more than the controls. Foreign body reaction was observed in Biostite® group.
Conclusion: It is suggested that Biostite® synthetic material can be useful in bone regenerative
therapies.
R. Khodadadi , Sh. Rokni , M. Najafipoor. ,
Volume 17, Issue 3 (7 2004)
Abstract
Statement of Problem: In order to eliminate the esthetic problem of metal collar in porcelain fused to metal crowns various techniques, such as shoulder porcelain, have been suggested.
Purpose: The aim of this study was to investigate the effects of repeated porcelain firing cycles on the marginal integrity of shoulder in porcelain fused to metal crowns, made of two kinds of alloys: noble and base-metal.
Materials and Methods: In this experimental study, four groups of ten brazen models (Die) were used. Metal crowns of groups A&B were made of a noble alloy and those of C&D of a base-metal alloy. Groups A&C had the shoulder width of 1mm and groups B&D had the shoulder width of 1.5mm. After degassing and opaqing, shoulder porcelain was completed in the area of shoulder. At this stage, the average vertical gap of margin was measured by a reflective microscope (400). Data were analyzed using ANOVA and Duncan tests.
Results: No simoltaneouse interaction between the type of alloy and the shoulder width was found (P=0.709). The type of alloy had a significant effect on marginal integrity (P=0.021) attributing the best marginal integrity of shoulder porcelain to base-metal alloys. Shoulder width played also a significant role on marginal integrity (P=0.00) indicating that the reduction of shoulder width would increase the marginal integrity.
Conclusion: According to these findings, the best marginal integrity of shoulder porcelain is achieved through shoulder width of 1mm along with base-metal alloys.
Sh. Rokni. , Sh. Mehdizade,
Volume 17, Issue 3 (7 2004)
Abstract
Statement of Problem: Ceramics and resins belong to the earliest tooth restorative materials. Nowadays new generations of these materials have provided a revolution in cosmetic dentistry. Ceramic Optimized polymer (Ceromer) is a newly made product that the bond between this material and base metal alloys, which are used widely today, is paid too much attention.
Purpose: The aim of this study was to evaluate the bond strength of targis (Ceromer) to three types of base metal alloys through three different surface treatment methods.
Materials and Methods: In this experimental study, ninety plates of Rexillium III, Silver cast and super cast alloys (3050.4) were prepared and surface treated through three different methods (air oxidation, vaccum oxidation and sandblast). All samples were then veneered with 1.mm thickness of Targis. After thermocycling, three-point bending test was performed by universal testing machine (Instron) to evaluate the amount of forces at crack or fracture times in Targis. The type of failure (cohesive or adhesive) was also evaluated microscopically. Statistical analyses were made using 2-factor ANOVA and Duncan tests.
Results: The type of surface treatment method caused a statistically significant difference in force rate required for crack and fracture in Targis. Sandblasting was found as the best method. The type of alloys, in all three methods, had a significant effect just on crack creation attributing the largest amount of force to Rexillium III. Adhesive type of failure occurred mostly in super-cast alloys through air-oxidation method, and cohesive type was more among silver cast alloys and sandblast method.
Conclusion: According to the results of this study, bond strength between Ceromer materials and base metal alloys is significantly great and Rexillium III alloy associated with sandblast technique the best combination.
M. Paknejad , Ar. Rokn , P. Motahhari , R . Mirza Toloei,
Volume 19, Issue 2 (4 2006)
Abstract
Background and Aim: Several biomaterials have been presented for regeneration of intraosseous defects and Bio-Oss is one of the most accepted materials in this field. Neo-Oss may be the first and only regenerative material made in Iran which few studies have been published about it. The aim of this study was the histologic evaluation of Neo-Oss in comparison with Bio-Oss in experimental rabbit calvarial defects. Materials and Methods: This was an interventional in vivo study. After elevating muccoperiosteal flap 18 standard defects (3×6mm) in frontal & parietal bone were made by round bur on the calvarium of 6 New Zealand rabbits. Defects were randomly assigned to one of the following treatments: 1-No graft (control), 2-Bio-Oss graft 3-Neo-Oss graft. After 4 weeks the animals were killed and histologic sections prepared. The studied variables consisted of inflammation, type of regenerated bone, thickness of bony trabeculation and foreign body reaction. Data were analyzed by Friedman test with p<0.05 as the limit of significance.
Results: The results showed that Bio-Oss was effective for bone regeneration. Inflammation (P= 0.026) and foreign body reaction (P= 0.002) in Neo-Oss was significantly more than Bio-Oss group. Thickness of terabecula in Neo-Oss group (66.7% thin) was significantly different from Bio-Oss (100% thick) and control group (50% thin 50% thick) (P= 0.006). In Neo-Oss group, granulation tissue containing giant cells was observed and the rate of resorption during 4 weeks was high.
Conclusion: Based on the results of this study, the healing capacity of Neo-Oss in comparison with Bio-Oss is not acceptable.
M. Paknejad, A. Rokn, A. Sabur, F. Elhami,
Volume 23, Issue 3 (25 2010)
Abstract
Background and Aims: Nowadays reconstruction of alveolar defects has become one of dentists' problems especially in areas which are going to get dental implants. Inorganic bovine bone mineral (Bio-Oss) is one of the most popular graft materials that acts as a structure for migration of osteoblasts. If migration, proliferation, and differentiation of osteoblasts can be promoted by a material, it would be possible to reconstruct more amount of bone in a shorter period of time. Milk contains vital proteins that regulate bone growth. One of these important proteins is lactoferrin. The aim of this study was to examine the effect of added bovine lactoferrin to Bio-Oss on osteogenesis.
Materials and Methods: Two doses of 50 and 500 µg/ml of lactoferrin were prepared. Ten New Zealand white rabbits were selected for this study. Four 6-mm symmetrical detects were created in each rabbit's calvarium. Two of these sites were filled with Bio-Oss that was wetted with two doses of lactoferrin. Third detect was filled with Bio-Oss alone and the forth one was left empty as control group. After 4 weeks histologic and histomorphometric analysis was performed.
Result: There was no sign of obvious inflammation in any of four groups. Also there was no difference among four groups in terms of vitality, type of new bone, and foreign body reaction. However, amount of bone formation in control group was significantly lower compared with the other 3 groups. Although lactoferrin containing groups showed little increase in bone formation especially in higher concentration, there was not statistically significant difference among the three test groups. Amount of remaining biomaterial also was lower in lactoferrin containing groups compared with the Bio-Oss group but the differences were not significant.
Conclusion: Although there was no significant difference among the test groups, it seems that the added lactoferrin increases bone formation. Considering the limitations of this study, more studies are needed in different concentrations of lactoferrin and different healing periods. Furthermore, because of possible washout of the lactoferrin from the defects, it would be helpful to find and evaluate a proper carrier agent for lactoferrin to see its real effects.
Mansore Mirzaie, Esmaiel Yasini, Ladan Ranjbar Omrani, Morteza Rokni, Hojat Darvishpour ,
Volume 28, Issue 4 (1-2016)
Abstract
Background and Aims: Microleakage is a criterion proposed for assessing the success of any restorative material. Complete seal is difficult especially for dentin margins compared to enamel margins. The aim of this study was to assess the microleakage at the enamel and dentin margins of class V cavities restored by two GIs and two self-etch adhesive systems.
Materials and Methods: This study was done on forty third molars. Class V cavities (3×2×2mm) were prepared on the buccal and lingual surfaces of teeth using high speed handpiece with 0.8 mm diamond fissure burr. The occlusal margins of the cavities in the enamel and gingival margins were placed 1 mm below the CEJ. The teeth were divided into 4 groups and the bondings were cured for 20 sec and the teeth were restored. The specimens were kept in distilled water at the temperature of 37°C for 24 hrs. The teeth were thermo cycled and cut in buccolingual direction using diamond disc under water. The dye penetration was evaluated using a stereomicroscope and the leakage was scored. The scores were compared using Kruskal-Wallis test while the paired comparisons were done using Bonferroni correction. P≤0.05 was regarded as significant results.
Results: Microleakage scores were similar at the occlusal and gingival walls of all test groups. At the gingival walls, the least microleakage scores were observed. “Fuji IX + SE bond” group showed significant differences with the “Fuji IX + G bond” and “Nanoglass + G bond” groups (P≤0.05). At the occlusal walls, the least scores were observed in the “Fuji IX+SE bond” specimens which were significantly different from the other groups (P≤0.05).
Conclusion: Self-Cure glass ionomers yielded less microleakage scores compared to the different types of light-cures due to the less polymerization shrinkage.
