Journal of Dental School
Year:2000 | Volume:18 | Issue:3|Papers Count:13

The purpose of this study was to evaluate the effect of scotchbond multipurpose plus (SBMPP) in comparrison to that of vitrebond on transverse and diametral tensile strength of set amalgam.A total of 60 specimens were selected and divided into two groups (with 30 cases for transverse test and 30 for diametral tensile test). Each groups were then divided into 3 subgroups as: control - vitrebond and SBMPP. Prepared specimens were then filled with amalgam (Luxalloy) in two fgrms using Teflon molds. All samples were tested by Zuick testing machine 1494 at 0.5 mm/min speed. Results indicated that specimens lined with SBMPP and Vitrebond had significantly lower transverse and diametral tensile strength than unlined specimens (p<0.05). Transverse strength of lined specimens with Vitrebond was significantly lower than specimens lined with SBMPP (p<0.01).In conclusion: Incorporation of adhesive resin liners within the body of amalgam can affect the mechanical properties of amalgam.

Thalassemia is an inherited genetic disorder of hemogolobin synthesis. It is Characterized by a quantitative reduction of their alpha or beta chains of globin. It results in an inherited problem in synthesis of a specific type of globin chain either due to deletion of the relevant gene or faulty translation of the genetic information.The onset of the severe from of the disease, homozygous beta thalassemia, occurs insidiously during the first or second year of life.The aim of this study was to evaluate relationship between thalasemia, caries and periodontal problems. A cross-sectional study was designed by evaluating 98 registered patients who had suffering from thalasemia and recieved monthly transfusion, during 1999.Results showed that:Over all 66 male patients, had been involved with an average age of 19.8 years and 32 female patients with an averge age of 155 years.There was a significant difference between those who had splenectomy compare to those who did not recieve this operation by an increase of both GI and DMF scores.

An exprimental study was designed to compare the invivo effects of Ariadent guttapercha with Roeko and Diadent. Twenty one mature Albinus rats (mean weight 200 ± 25 gr) were selected for this trial.Four intradermal incisions were made at the dorsal part of each rat, with a polyethylene tube containing a Gutta percha cone being implanted in each incised area.Animals were sacrificed at 15,30 and 60 day intervals and the tubes together with adjacent tissues were excised.All the speciemens were prepared histologically and stained using H & E staining method. Histological variables were assessed including diameter of capsule, inflammation, vascularity and necrosis using light microscope.Results using statistical analysis revealed that the diameter of the capsule was significantly different at 60 day interval in comparison to the control group (P< 0.03).The inflammatory and vascular variables were also found to be significantly different when compared to the control group at 30 day interval (P<0.008).None of the cases presented necrosis. In conclusion: It seems that Ariadent Guttapercha could be tolerated and is as acceptable as the two other brands (Roeko - Diadent) for it's biocompatibility.

A single blind cross sectional study was designed to evaluate the nonverbal communication of the 5th and 6th year Dental students. Sixty six male and 24 female dental students participated for this investigtion. All students were evaluated while treating their patients according to the nonverbal communication criteria checklist standards. Evaluating all students using a scale of 0-10 showed that the mean score was at 5.6 with no significant difference between male and famale students (girls=5.25, boys=5.72, P=0.159). The posture of the students was found to be overall satisfactory except for vertical status in sitting position on the dentist chair. All other items concerning nonverbal communication skills in relation to facial expression were below average. It is there fore, recommended to include the communication skills in the training programmes of dental students.

The aim of this study was to determine the TMD status in three different age groups: I (15-19), II (35-44), III (65-74). Sample size was 720 people of Tehran province in 1995. From the total of 720, 377 were females and 343 males.Cases were selected based on a ramdomized clustered stratified manner. Pain, muscle tenderness, clicking and maximum opening of the mouth ( objective and subjective) were measured in addition to the age, sex malocclusion, economic status and the level of education. Results revealed that 11.4% of the samples had subjective symptoms while 6.2% had objective signs (1.8% muscle tenderness 4.4% clicking). Limitation of the mandibular movements was increased in older people (p<0.01). Over all, TMD incidence was found to be less than the results reported from other countries particulary industrialized ones.

Primary hyperparathyroidism (PHP) is an alteration in the homostasis of calcium and phosphorus which affects bone metabolism. The most frequently bone change is known as osteopenia, signs of osteitis fibrosa with bone tumors which rarely occur in different locations.Although the central giant cell or "Brown Tumor" in mandible was frequently reported in association with hyperparathyroidism, but location of this tumor in the maxilla is an exceptional finding.Early recognition of PHP reduces the risk of morbidity and distribution of lesions.On this basis a case of primary hyperparathyroidism is presented herd as: "Brown Tumor" in maxilla with peripheral extension of it in oral mucosa. Patient had undergone surgical- PGCG in mandible without noticing the hyperparathyroidism. Clinical investigation indicated that the patient was suffering from hyperparathyroidism. This was later confirmed by radiographic examination and biochemical tests. Patient was then refered to Imam Khomeini General Hospital for excision of parathyroid adenoma. Results indicated a normalized metabolic situation. Resection of oral tumor performed, would however take a longtime to achieve regeneration of diffuse bony lesions which makes follow up of the case so critical.

This epidemiologic study was designed to evaluate the dental health status of two age - groups: a - Patients with 35-44 years of age (178 individuals) and patients above 64 years of age (150 individuals). In this survey the W.H.O assessment criterias were recorded. Results revealed that the DMFT index was at 15.4±7.3 in group a with 29.01±5.7 in group b. The detailed data achieved showed that the DT in 35-44 year olds was at 2.6 while this was at 1.11 for 65-95 year olds.Figures for MT was 10.05 in group a 1.117 with 27.6 in group b The DMFT score was found to be higher in females compare to male patients.The rate of edentulous patients was 7.9% in 35-44 year olds while this figure was at 70.7% in those over 64 years of age.

This experimental and prospective study deals with the investigation of the effect of the terminal point of the canal filling (1mm above the apex) on the complex of apical - periapical tissues.The crowns of the canine teeth of twelve healthy and mature cats were cut and the pulps were afterwards intentionally afflicted with pulpitis. The canals were then cleaned as usual (up to 1 mm above the apex), formed and filled with gutta percha. After six months animals were killed and samples were histologically evaluated.The histologic results verified the presence of a very slight inflammation which was due mostly to the lymphocyte and plasma cells. Inactive macrophage cells (histocysts) were rarely seen. This degree of inflammation does not indicate a meaningful difference in comparison to normal samples and verifies complete healing of the complex of apical - periapical tissues.

Changes of up to 80°C has been reported for oral cavity temperature. This could well effecti on the nature of restorations for example failure of bonding of adhesive restorations. It is advocated that using opaque layer in porcelane to restorations could reduce this problem. This experimental study was designed to evaluate the effect mentioned using finitelement analysis method.Results showed that cooling has a more destructive effect than warming process restorations with the presence of opaque having a finitelement analysis effect on restorations.

The purpose of this study was to evaluate the root coverage procedure using a partial thickness double pedicle graft (test group) and compare it to full thickness double pedicle graft (control group).Eight patients with 20 paired (mirror image) defects with Miller's class I,II gingival recessions were randomly selected in two group.After initial treatment, the clinical measurments were taken at baseline, these parameters included recession depth, recession width, clinical attachment level, probing depth and width of keratinized tissue. Measurements were repeated at 3 months post-surgery. A mucosal double papillary flap was elevated and the respective root thoroughly planed in the test group, during the surgical procedures. The connective tissue graft which harvested from palate, was then adapted over the root and sutured with 5-0 gut followed by the pedicle flap securing over the graft with 5-0 gut sutures. Surgical technique was similar in control group except that the pedicle which was prepared in a full thickness manner. Results demonstrated that the amount of mean root coverage obtained was 89.14% (2.83mm) in test group and 85.7% (2.75mm) in control group. No statistical differences were found in mean reduction of vertical recession, width of recession and probing depth between test and control groups. In both procedures the width of keratinized tissue was increase after three months and the difference between the two groups was not statistically significant.In conclusion: connective tissue with partial and full thickness double pedicle graft can be used successfully in the treatment of gingival recession.

Bacteria and their products play a major role in initiation and perpetuation of pulpo-periapical pathosis, and therefore the most important phase of endodontic treatment is the elimination or reduction of bacteria from root canal system.The purpose of this study was to compare the antimicrobial effects of two intracanal agents, an antibiotic combination and calcium hydroxide on infected dentinal tubules.Dentinal tubules of 60 root canal specimens of human teeth were infected with Enterococcus faecalis (RITCC 1918) for 3 weeks, and then exposed to a calcium hydroxide / saline paste or a mixure of ciprofloxacin, Metronidazole and tetracycline (25 microgram/ml of each drug) for periods of 24h, 48h, 7days.The bacteriological samples were taken by shaving the inner dentine from root canal with dental bur. Powder samples were incubated and the quantity of bacteria present assessed using spectrophotometry. Furthermore, the target organisms were cultured on blood agar plates and total numbers of colony forming units/m1 (CPU/m1) were counted.Results indicated that the drug combination effectively kills bacteria in the tubules after a 24h period of exposure, in contrast calcium hydroxide was in effective against E.faecalis even after 1 week of exposure.

This research was carried out on 48 patients aged from 12 to 67 who refered to Oral Surgery Department at Tabriz Dental school for their teeth extraction.Patients were divided into 4 groups as follow:Group A1: Patients with teeth on both sides of lower jaw to be extracted. One side, was adopted as Experimental while the other side was considered as control (Inferior alveolar nerve block anesthesia or mental nerve block anesthesia).Group A2 Patients with teeth on both sides of lower jaw to be extracted, with the difference that only on one side Mod I.O.A was adopted with no injection of any kind on the other side. Group B: Patients with teeth only on one side of the lower jaw to be extracted, in which Mod I.O.A was employed.Group C: Patients, in whom inferior alveolar nerve block anesthesia was failed and then Mod I.O.A was adopted for Extractions.To perform this technique, a manual terphinator was designed. Use of this device removes the need for incision of mucosa and the bone at the apex of the tooth. This is because, these tissues will be perforated. rated during the technique, with an access to spongeous bone.Results showed, the effect of the anesthetic solution in this technique is rapid, short and limited. In addition there is no relationship between the degree of anesthesia with age, sex or the kind of tooth to be extracted. In spite of the passage of the anesthetic solution from the midline, it's distribution through the bone differs among the different people.