فهرست مطالب
Dental Research Journal
Volume:2 Issue: 2, Mar 2005
- تاریخ انتشار: 1384/12/02
- تعداد عناوین: 8
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Page 1Introduction
In spite of multiple applications of bioactive glasses, these materials have not been evaluated yet for ridge augmentation. Due to the large number of patients who need ridge augmentation and the benefits of Nova Bone, in comparison with other alloplasts, this study was fulfilled for evaluation of Nova Bone ability in ridge augmentation.
Methods
The samples of this experimental study are four dogs. In each one, two months after extraction of lower premolors and alveolectomy of that area, one side was augmented with NovaBone alone and the other side was augmented with the combination of Nova Bone and autogenous bone. After 2,4, and 6months, changes in ridge height were evaluated with clinical and radiologic methods. In the end of study, the dogs were sacrificed for obtaining histologic samples.
Results
In the alone NovaBone group, grafts of two ridges were exposed, but in the other two ridges, in spite of insignificance of statistic test, the amounts of ridges augmentation were clinically significant (mean: 6.5 mm) and new tissue, containing bony texture, was formed. In the other three ridges, in addition to significance of statistic test and formation of new tissue containing bony texture, the amount of ridge augmentation was considerable(mean: 5.5 mm). There wasn''t significant difference between two forms of Nova Bone usage.
Discussion
Without considering of the results of statistic tests, the amounts of ridge augmentations were clinically significant in both groups. Therefore, considering the radiologic and histologic findings, and the biocompatibility of NovaBone, both forms of this material can be successful in ridge augmentation.Keywords: Ridge augmentation, Bioactive glass -
Page 1Introduction
This study was carried out in order to compare mineral trioxide aggregate (MTA) and dycal in dog’s teeth as pulp capping agents.
Methods
After general and local anesthesia forty-two teeth of three dogs were used. In each tooth a class V cavity was prepared and the pulp was exposed using No.1 round bur. Then the exposed area was capped using either MTA or calcium hydroxide and the rest of the cavity was restored by amalgam. Radiographic image was taken before the procedure and after 4, 8 , and 12 weeks. The animals were sacrificed at 4, 8, and 12 weeks and the teeth were prepared for H&E staining. The pulps of the teeth were evaluated for inflammation, necrosis, and formation and thickness of calcified bridge. Histologic data were analyzed by Kruskal Wallis, אַ², Cochran, and Friedman tests.
Results
Histopathologic results showed that in four weeks, MTA had significant differences with calcium hydroxide in the presence and thickness of calcified bridge (p=0.046) as well as inflammation (p= 0.014) and hyperemia (p=0.014). Eight weeks MTA specimens showed significant difference in thickness of calcified bridge (p=0.008). Twelve weeks after pulp capping, the amount of necrosis and chronic inflammation were higher in dycal specimens; however, there was no significant difference between two experimental groups. Radiographic evaluation did not show any periapical lesion, internal and external resorption, or widening of periodontal ligament in none of the teeth at all time intervals.
Conclusion
Based on the result of this study, MTA showed to be a more reliable material as pulp capping agent in comparison with calcium hydroxide.Keywords: Gray MTA, Pulp capping, Calcium hydroxide -
Page 1Introduction
Radiographs provide unique information about the status of periodontium and permanent records of condition of bone throughout the course of the disease. Interproximal images record the distance between the Cementoenamel Junction and the crest of the interradicular alveolar bone, more accurately. The aim of this study was to investigate the effect of different vertical angles of x-ray tube (0, -10, ) degrees in horizontal and vertical bite wing techniques in assessment of bone loss.
Methods: One hundred and twenty bitewing radiographs from 150 interproximal surfaces from 10 dried skull were by three degrees (0, -10, ) prepared. The level of alveolar bone loss was measured using ruler on the skulls and radiographs and data were registered. Type of bone loss was horizontal.
Results
The maximum differences between invitro and radiographic findings were and -2.745 mm. In all areas, radiographic data were less than clinical diameters. In all areas, by using zero degree vertical angulation, there was less difference between mean of radiographics and clinical measurements.
Conclusions
with changing vertical angulations, using 0, , and -10 degrees, a wide range of measures (2.75-3mm) in amount of alveolar bone loss were ohtained for evaluating periodontal disease or following them up, accurate and reproducible images are necessary. In this study we concluded that zero vertical angulation degree decrease the angulation errors and reduce understimation of radiographic assessment of alveolar bone loss. -
Page 1Introduction
A large number of orthodontists prefer to rebond the failed bonded brackets or use recycled brackets in some instances. The aim of this study was to compare the shear bond strength of rebonding with using recycled brackets on enamel surface.
Methods
Bonding of brackets on the surface of extracted first bicuspids was tested in five different groups to compare their shear bond strength (SBS): Group N, new bracket on enamel surface of newly extracted teeth as a control group; Group R, recycled bracket on newly extracted teeth; Group NR, new bracket on the cleaned enamel surface of previously bonded teeth with Tungsten Carbide bur; Group RE, reused bracket on cleaned surface of previous teeth; and RR group, with brackets undergone two times of recycling on the newly extracted bicuspids. Adhesive Remnant Index was specified for each group.
Results
The highest SBS was related to control group (group N) which rated as 12.00 Mpa, and the next scores were related to groups NR, RE, RR, and R with 11.85, 10.80, 10.00 and 9.94 Mpa, respectively. The differences between groups N and NR with groups R and RR were significant.
Discussion
Rebonding had no significant effect on reduction of SBS. Tungsten Carbide burs are suitable for removing of remaining composite from brackets and enamel surface and finally, chemically recycled brackets had a clinically acceptable SBS.Keywords: bracket, chemical recycling, shear bond strength -
Page 1Introduction
Recurrent oral aphthous is one of the most common ulcerative lesions of the oral cavity which no specific treatment has been introduced for it, sofar. Some studies suggest the zinc deficiency as one of the etiologic factors in aphthous ulcers and also in other experimental studies, zinc composition has been effective in aphthous treatment. The aim of this stud was to determinate the serum zinc level in normal and aphthous individuals.
Methods
This was a case-control study in which 88 individuals (44 normal and 44 aphthous patients) were studied. Both groups were equalized for age and sex. Sampling was convinence. The blood samples were taken and the zinc level of them were measured by Atomic Absortion Spectrometer and then the results were statistically analyzed with t-test.
Results
This study showed that the average serum zinc level in the case group was 70 9µg/dlit and in the control was 94 14 µg/dlit and there is a significant difference between two groups (P -
Page 64Introduction
The materials used for obturation of root canal system may be extruded through apical foramen into the periapical tissue. Therefore, biocompatibility of these materials is very important. The purpose of this study was to evaluate the in vivo biocompatibility of three conventional endodontic sealers: AH26, Roth 801, and ZOE after their subcutaneous implantation in rats.Methods
Twenty-two mature male Albino rats, weighting from 250 to 500grs were used. Each animal received four polyethylene implants; three implants were containing test sealers and one was empty tube as negative control. The animals were sacrificed at third day and third month after implantation and the implants were dissected with 2cm of surrounding tissue margins. Then, tissue reactions to the test materials were evaluated histologically and quantitatively by a pathologist under light microscope, after histologic processing and staining with H-E. The obtained results were analyzed statistically by Mann-Whitney test.
Results
After 3 days, tissue reaction to ZOE was more acute than AH26, Roth 801, and control group. But after 3 months, no significant difference was observed among these three sealers and among those and control group.
Discussion
According to this study, all of the sealers cause inflammatory reactions immediately after contact with tissue, but the intensity of these responses decrease with time. The acute responses of third day changed to chronic, proliferative, healing processes in third month.Keywords: Endodontic Sealers, Tissue reaction (response), Subcutaneous Implantation -
Page 83Introduction
Microorganisms have an essential role in pulpo-periapical pathosis, therefore obtaining a successful treatment has a direct relationship with their elimination. According to previous studies, the most reliable method of sterilization is autoclave ,but in some instances there are limitations for using this method, and we need an alternative .One of the most popular and wide-spread materials in this field is Micro10 solution. The aim of this research is to determine the sterilization effect of Micro10 solution on endodontic hand instruments.
Methods
1200 endodontic hand files were selected for this study, (15 groups of 80 files). Each bacterial group was prepared in 0.5 Mc Farland standard concentration (1.5 ×108). Every 5 groups of files were contaminated with one of bacterial samples. Then each group of contaminated files, underwent sterilization process, using one of the following methods: a) Application of autoclave, b)Application of 2% Micro10 solution, in 15 minutes, c) Application of 2% Micro10 solution, in 60 minutes, d) Application of 10% Micro10 solution, in 15 minutes, and e) Application of 10% Micro10 solution, in 60 minutes.
Results
The results of this study indicated that only in group 1 (autoclave) all of samples were sterile, but in other groups sterility diminished to 82.1% (group2), 83.3% (group 3), 90.8% (group 4), and 93.3% (group 5).
Conclusion
Only autoclave is a reliable method for obtaining a sterile condition and Micro10 solution at the most is just a good disinfectant, especially in 10 % concentration. Also we concluded that the concentration of Micro10 solution has a direct effect on its killing ability of bacteria, while duration of process (60 minutes versus 15 minutes) has no effect.Keywords: Sterilization, Micro10 Solution, Disinfectant