JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2002 | Volume:14 | Issue:1 (40)|Papers Count:8

Temporary restorative materials are an important component of endodontic therapy. They must both adequately seal the access preparation between appointments and protect the obturated canals from microleakage until a permanent restoration can be placed. Standard ednodontic access preparations were made in 64 non- carious, nonrestored crowns of extracted human molars and premolars.Following access preparation, cotton pellets were placed in the pulp chamber, remaining minimum four mm for placement of test materials.They were divided into there groups, including positive and negative controls. The access preparation was sealed with one of the following materials: Cavisol, Coltosol and ZOE. The specimens were thermocycled (5c to 55 c for 50 cycles). Immersed in methylen blue dye for seven dayds, sectioned, and evaluated under a streomicroscope for microleakage.Results showed that there was not a statistically significat difference in leakage between the cavisol group and coltosol group. While ZOE exhibited greatest leakage and had a significant difference with cavisol and coltosol groups. The results of these study confirms the usefullness of cavisol and col to sol as temporary restorative material between endodontic appointments.

The purpose of a classification for partial edentulous arches is to simplify identification and enhance its teaching. A classification also allows a longitudinal comparsion of various classes of partial edentulous arches to determine whether the teaching of partial denture design is consistent with the relative frequencies of partial edentulous arches. This descriptive study evaluates the frequency of partial prosthesis classification among the people of Yazd. Sex, tooth loss classification, age and degrees of graduation were studied (300 males and 300 females). The results showed that Kenndy class III and class I classification were the most frequently in upper jaw and lower jaw respectively. If the cases that need fixed prosthesis exclude of this study, the Kennedy cl I classification would become the most frequently in both two jaws. With increasing the age, the frequency of ClI kennedy classification. Would become greater but with higher degrees of graduation, the frequency of cll classification would decreases (Chi-square test).Comparision with previous studies provide clinically and educational useful information for dental training and educational useful information for dental training and continuing education.

Prenatal hypoplasia is a generalized hypoplasia. Some diseases during pregnancy and, very low birthweight can create this type of hypoplasia. In this patient all of posterior teeth and two third of incisal parts of anterior were involved with severe hypoplasia.

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 resonable 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 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. Tukeys 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.

Recent years there is a considerable attention to infection control in dentistry. The news from publication, as well as authorities about the relationship between dentistry and Aids causes anxiety and uneasiness of the patients and dentists The emphasis on principles of personal protection and sterilization is but also for other infection.According to compulsory protocol for using autoclaves in dental offices various autoclaves are imported and some types manufactured in Iran.Choosing any system to buy and to invest necessitates knowledge and awareness.In this article different aspects about autoclave and important notes related to sterilization with autoclave and protecting procedures will be discussed.

To compare the shear bond strengths of composite to enamel using sctchbond multi-purpose and Syntac with and without primer and Single bond on moist and dry enamel.Small flat areas on the buccal surfaces of sixty sound human premolars were ground in enamel with diamond disk. Teeth were divided into six subgroups for each of three adhesives (n=10). In all groups, the surface was etched for 15 seconds with 37% phosphoric acid, rinsed with water for 10 seconds. Each of the two dentin bonding systems (scotch bond Mulitpurpose n=20 & syntac n=20) were applied on the etched enamel surface with and without primer. The Single bond was tested on moist and dry etched enamel (n=20). After adhesive application, Heliomolar composite restorative materials were applied in 3.1 mm diameter plastic mold to the completed specimens were stored in water for one week before testing.Shear bond strength were measured using an instron universal testing machine (40204)Data were subjected to two ANOVA and Tukeys multiple comparison test. Mean shear bond strengths observed in this study were between 20.12±9.24 MPa (Scotch bond Multi-purpose with primer) to 37.86±7.6 MPa (Single bond on moist enamel). The mean shear bond strength of the subgroup without primer was significantly higher than subgroup with primer. The mean shear bond strength of Single bond on moist enamel were significantly higher than the subgroup of Single bond on dry enamel. Mean shear bond strength between all groups were significantly different with each other (P<0.0001).The results of this study suggest that mean shear bond strength Single bond on moist enamel is higher than the other adhesive system. Using of primer show significantly lower bond strength than the without primer.There was significant different bond strength between moist and dry enamel with Single bond.

Maxillary expansion has prevalent use in orthodontics. The aim of this study was to evaluate the efficiency of removable appliance in rapid palatal expansion. 11 patients with posterior cross bite who had a mean age of 107 months were treated. Each appliance had an expansion screw and posterior bite plate. The patient advised to open the screw one time per day. After preparation of pre and post- treatment casts, photographs, occlusal X-rays and Lateral cephalograms were requested, 28 Linear and angular parameters were measured from preand post treatment cephalograms which were compared by paired t.test.1- Based on occlusal X-ray removable appliance in 75% could open the maxillary suture.2- Point a moved to anterior.3- There was no significant rotation in the jaws.4- Palatal plane did not translate down but anterior lower facial height was increased.5- Anterior upper and lower teeth did not show significant differences.We find that such removable expansion appliance is efficient, specially in the long face cases that have tendency to open bite. The important factors in treatment with removable expansion appliances are patient cooperation and good appliance retention.

A Comparative study of the absorbency properties of different brands of endodontic paper points (Diadent, Roeko, Ariadent, Ali) has been conducted. Four brands of standardized absorbent paper points were tested. 30 paper points of each brand (size 40) were selected randomly and each dry paper points were weighted using a laboratory balance with 10-5 gr accuracy. A length of 16mm from the tip was then lowered in normal saline for 5 seconds. The moist paper points were weighted again and the differences between two measurements were taken.In the second method we used lower premolar human teeth which were prepared endodonticaly (MAF=40 & Flaring = 60).Before drying with each paper points, the tooth canal was washed with 10cc of normal saline. And the difference between dry weight and postimmersion weight were measured.In both methods Diadent shows the highest absorbency properties then Roeko and Airadent & Ali but were not statisticaly significant.According to intracanal method Diadent has absorbed 965.333xI0-5gr of normal sa line & Ariadent 855.8´10-5 gr & Roeko 845.667´10-5 gr Ali 443.8´10-5gr.According to other method Diadent has absorbed 972.8´I0-5gr of normal saline & Roeko 866.4´I0-5gr & Ariadent 588.133´I0-5gr.