JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2003 | Volume:14 | Issue:4 (43)|Papers Count:10

Investing methods affect marginal adaptation of casting restorations considerably. There are few studies comparing metal ring and ringless casting technique for fixed restorations and there is no adequate scientific data to support the use of ringless casting technique. so, this study evaluated the marginal gap of full casting crowns fabricated with "one layer wet ring liner" and "ringless casting technique". This is an experimental study. 10 of the same wax patterns immediately after refining margin on the metal die, were invested under each foretold investing method, using phosphate boarded investment (Accufit). Shape, internal diameter and length of the casting rings using in metal ring and ringless casting technique were the same. Casting were produced using base metal alloy (Verabond). Marginal gap of each casting, along four predetermined reference marks on the die, under stereoscopic microscope. were photographed by digital camera. Then a "blind" operator performed the measurements in micron using scale of Photoshop. Data were analyzed with Univariate ANOVA at P=.05. Marginal gap (Mean±SD) of casting fabricated with the "one layer wet ring liner" was (46±32µm). and with the "ringless casting technique" was (163±77µm). "One layer wet ring" liner produced statistically significant (P<.001) smaller marginal gap than "ringless casting technique". Marginal gap showed no statistically significant (P>.05) difference among four reference marks in each investing method. Distribution of dispersion and inconsistency of casting fit showed no statistically significant (P=.102) difference between investing methods. "One layer wet ring liner" is more desirable method to fabricate dental casting with clinically acceptable marginal gap than "ringless casting technique".

Application of sealer is essential in every obturating technique. Since apical extrusion of sealer during obturation is not uncommon, biocompatibility is of prime importance. Roth's 800, Grossman's formula with ZOE base, Apexit with calcium hydroxide and Roth's 801 (Apadana Co.) were examined for biocompatibility. 80 male Sprague-Dawley rats with average weight of 800-400 grams were used. All the sealers were mixid according to the manufacture's instructions and placed into polyethylene tubes. Polyethylene tubes were selected as controls. The animals were classified in four groups, each containing 20 rats. After incisions, the materials were implanted subcutaneously in dorsal surfaces of animals. The materials were evaluated 4, 10, 30 and 60 days after surgery. After these periods, four rats of each group were selected and sacrificed with high doses of chloroform. After dissecting, the samples were inserted into 10% formalin solution and examined single blindly by oral pathologist in two stages at the Tehran dental faculty. The samples were classified on the basis of inflammation into four groups. Group 0 (Zero) (without inflammation), group 1 (with mild inflammation), group 2 (with moderate inflammation), group 3 (with severe inflammation). All the results were statistically evaluated by Kruskal-Wallis and Mann-Whitney tests. In the 4th day, in the control group moderate inflammation were observed which is statistically significant. In the 10th day, in the control group mild inflammation and in the other three remaining groups sever inflammation were observed which is statistically significant. In the 20th day, in the control group no,inflammation and in the Apexit group and Grossman's group moderate inflammation and in the Apadana's sealer group moderate to severe inflammation were seen which were statistically significant. In the 60th day, there was no inflammation in the control group. In Grossman's sealer group mild inflammation and in Apexit's sealer group mile to moderate inflammation were observed. In statistical manner, there is no significant difference between the Apadana's Roth sealer and Apexit's sealer but between these two sealers and Grossman's and the control group, there are significant statistical difference with P=0.008.

Esthetics of artificial teeth were emphasized with development of science. The tooth proportion of width to length should closely parallel the facial properties. Natural tooth size and its relation with other factor like the canines distance can aid to select correct tooth size. This article describes a method to select denture teeth. It describes the relations of the VDO and VDR to the length of right central incisors and width of right central incisor to chelion to chelion width and canine distance. One hundreds patients were selected and the measurement were made. Mean and standard deviation were computed. One sample K.S and ral r'spearman were used. There was a strong correlation between VDO, VDR, length and width of right central, ARCD. (P<0.05)

The purpose of this study was the evaluation of Iranian dental stones and comparison between Iranian and foreign ones. In this investigation, compressive strength and reproduction of details were compared between Pars Dandan, Almas and Hinrizit stones. The later is accepted by ADA (American Dental Association). In this study, the number and the methods of preparation of specimens and test conditions were done according to the ADA specification No 25 and Iranian standard organization specification N02569. In the setting expansion test, the mixture of each stone was poured in a V shaped steel dish and one minute before the setting time and two hours after the beginning of mixture of stone, the amount of expansion was recorded with a micrometer and then the percent of expansion was calculated in relation to the primary length. In the compressive strength test, the mixture of each stone was poured in the cylindrical steep molds. One hour after the beginning of mixture, the compressive strength of specimens was evaluated with Instron apparatus. This test was repeated five times for each stone. In the reproduction of details test, three grooved plates and three metal cylinders were used. The mixture of each stone was poured in to the beginning of mixture, all the specimens were inspected with a microscope by magnification of 6 and 12. This test was repeated 3 times for each stone. The setting expansion of Hinrizit stone is 0.018±0.01 (within the limits of ADA standards which is 0 to 0.2%), the compressive strength is 21.22±3.28 Mpa (the minimum of ADA standard is 20.6 Mpa), and the reproduction of details is also within the limits of ADA standards (which the minimum is 2 of 3 test). 1. The setting expansion of Pars Dandan stone is 0.69±0.03(out of the limits of ADA standards), the compressive strength is 13±1.96 Mpa (out of the limits of ADA standards), and the reproduction of details is within the limits of ADA standards. 2. The setting expansion of Almas stone is 0.22%±0.01(near the limits of ADA standards), the compressive strength is 8.4±1.59 Mpa (out of the limits of ADA standards) and the reproduction of details is within the limits of ADA standards. 1. Unhemogenousity of Iranian stones powder was caused by uncontrolled temperature, pressure and humidity in the production process of stone. This unhemgenusity may cause the increase of water needed in the mixture and decrease of compressive strength. 2. Impurities such as sodium chloride was responsible for increasing of Iranian stone's setting expansion.

The aim of this research was conducted to clinically compare the efficacy of Persica toothpaste comparing to Darugar 1. This study was a single blind clinical trial. Every subject was accounted both as a experimental and control groups (Crossover study). Thirty dental school students participated in the study. (20 female and 10 male), with mean of age 23 years. They didn't have any systemic disease. Subjects have used Persica tooth past for 2 weeks and the following 2 weeks, Darugar 1, has been used. Tooth brushing method was modified stillmans and toothbrush type was soft Butler. At the end of 2 weeks period, the indexes of plaque of gingival have been recorded and analytical evaluations were done. Results showed that the mean of recorded plaque index for Darugar 1 was 49% and Persica 32% and gingival index, (for Darugar was 9% and Persica 6%. At end inter groups examination (Paired t-test) was done and it showed experimental group had significant effect on decreasing of Plaque and gingival index (P<0.00l). With regard to the potential side effects of the chemical agents of the toothpaste, in comparison to the herbal compounds, their production would be beneficial. Due to the limited scope of this research and further work on herbal toothpaste including taste and fluoride content, are recommended.

In the past two decades caries risk prediction has been and important subject for investigators. Caries risk assessment is an effective method for the prediction of future caries. By CRA the high-risk groups are determined. Then the prevention programs in relation to high-risk groups, be perform. This article is the results of a research project which has been performed by the author in Tehran. 218 primary school children (7 years old) have participated in this study. They have been examined for caries risk factors in three stages: 1- By a questionnaire for personal and socio demographic information. 2- Bite wing radiography to diagnosis the incipient proximal caries. 3- Dental examination of the student. Results of the research showed 34 person (15.6%) were high-risk, 63 person were low-risk and 121 person (55.5%) were moderate risk. Some of the caries risk factor have been also evaluated.

The aims of this study were to evaluate the clinical and microbiological effects of mechanical debridement with the adjunct of systemic coamociclav subjects with Localized Juvenile Periodontitis (UP). Patients harboring subgingival Actinobacillus actinomycet comitans (A.a) in deepest Pocket 6/6 23 patients aged 14-25 years in one quadrant of the mandible were exposed to Flap surgery and in contra lateral quadrant Scaling and Root Planning was Performed under local anesthesia. The patients randomly distributed in 2 different sample. One samle (test) received antibiotic during periodontal therapy and 6 month later. And others don’t receive drug (control). Clinical Parameter measured in 0 day, 3, 9 and 12 month later. After 12 month the results were as follow; In group A+1 (Antibiotic and surgery) decrease Probing Pocket depth (PPd) 3 mm, gaine of Attachment (A) 3.1 mm(P<0.001). Group A+2 (Antibiotic with scaling) decrease PPd 1.96 mm, gaine of A 1.35 mm. (P < 0.001) But in group A-1 (No antibiotic & surgery) PPd increased 0.16 mm and loss of A was 0.19 mm. Group A-2 (No antibiotic & scaling) PPd increased 0.29 mm and loss of A 0.38 mm. All the subjects first were 100% Aa + But after 1 year demonstrated in group A+I 8.6%, A+2 25%, A-I 81.8% and in A-2 100% . So Bop in A+ 1 0%, A+ 28.6% , A- 27.2, and in A-2 72.7%. This results suggest coamoxiclav was effective in reducing PPd, eliminating Aa and gaine of attachment. And they were stable for 1 year.

Ameloblastoma of the jaws that involves the mandible frequently (80%) is a benign tumor with locally invasive character that has the most important recurrence feature. This tumor has the recurrence rate 55%-90% for curettage and enucleation procedures and 5%-15% for complete resections. Also recurrence of tumor in autogenous bone graft may occur and destroy the grafted bone. In this case presentation will be presented. One case of recurrence of ameloblastoma within autogenous rib graft.

Improved dental stone has been widely used for producing dies for the fabrication of restorations with the lost-wax technique. Improved dental stone is used for several reasons, most often because of its reasonable cost, ease of the use, and ability to produce consistent results. The purpose this study was to compare the dimensional accuracy of dies made three type IV die stones. A metal master model, containing 2 complete crown fixed partial denture (FPD) abutment preparations, was fabricated. Three die stones were compared Ultra rock, SH074 and Begostone. Ten master casts were fabricated for each die material from a master metal model using conventional prosthodontics laboratory techniques. A mean measurement and percent relative change for each dimension was calculated. One-way ANOVA revealed that significant differences existed among the materials. Tukey's multiple comparisons testing ranked the dies as follows: from largest to smallest; SH074, Ultrarock, Begostone, Maste model. Begostone die material had the least mean dimensional change from the master model.