[Comparison of the intranasal and intraperitoneal injection of MPTP on density of dark neurons in pars compacta of substantia nigra in animal model of Parkinson's disease]

Background and Objective: Parkinson disease [PD] is the second most common neurologic disorder that results following degeneration of dopaminergic neurons in the pars compacta of substintia nigra [SNc]. The 1-methyl-1,2,3,6-tetrahydropiridine [MPTP] is a chemical neurotoxin that widely used in animal models of PD. This study was carried out to evaluate the numerical density of dark neurons [DNs] in the SNc in mice subjected to intraperitoneal and intranasal injection of different doses of MPTP

Methods: In this experimental study, 90 male adult BALB/c mice were randomly allocated int four experimental groups including: group 1 [MPTP was injected via i.p. at the dose of 20mg/kg per 2 hours for 4 times], group 2 [MPTP was injected via i.p. at the dose of 30mg/kg for 5 consecutive days], group 3 [MPTP was injected via i.n. at a single dose of 1mg/kg], group 4 [MPTP was injected via i.n. at a single dose of 1mg/kg], four sham and one normal groups. 20 days after the final injection, the animal's brain were removed and stained by toluidine blue. Numerical density of DNs was counted

Results: Intranasal injection of MPTP significantly increased density of dark neurons in the pars compacta of substintia nigra in compare to intraperitoneally injection of MPTP [P<0.05]

Conclusion: Intranasal injection of MPTP is more effective manner to induce degeneration of neurons in substintia nigra in animal model of Parkinson's disease

[Psychological disorders among inhabint residing in poor social district of Gorgan, Iran]

Normal psychological behaviour is one of the general concept of health. This study was carried out to evalute psychological disorders among inhabint residing in poor social district of Gorgan, Iran. This cross-sectional study was done on 376 subjects [188 males and 188 females] with simple random sampling method. Data were gathered using the general health questionnaire [GHQ-28]. Data was analyzed by SPSS-16, Kruskal-Wallis and Pearson tests. The prevalence of psychological disorders was 37% [33.5% in men, 40.4% in women], depression was 24.45% [22.5% in men and 26.4% in women] and anxiety was 31.6% [31.2% in men, 32% in women]. Social affairs disorder 21% [19.2% in men, 22.7% in women] and psychosomatic disorders in 28.5% [22% of men, 35% of women]. The relationship between psychological disorder with economic level and family size was significant [P<0.05]. This study showed that 37% of inhabint residing in poor social district of Gorgan, Northern Iran had psychological disorders

[Effect of using calcium hydroxide as an intra- canal medicament on apical seal]

Commonly, calcium hydroxide is used as an intra-canal dressing for disinfection and accelerating the repair of periapical lesions.The purpose of this study was to determine the effect of using calcium hydroxide as an intra-canal medicament on apical seal In this experimental study, total of 60 one-rooted extracted human central incisors were instrumented with step-back technique. K-file [No 35] was selected as master apical file and flaring was done up to 60. The teeth were randomly divided into two experimental each containing 20 teeth and two control groups each containing 10 teeth. In one experimental group, the root canals were filled with calcium hydroxide. After one week, the paste was removed using 35 K-file and normal saline irrigation. The root canals of experimental and negative control groups were obturated with gutta percha and AH 26 sealer using lateral condensation technique. In the positive control group the root canals were not obturated. Dye penetration technique was used for evaluating the rate of longitudinal microleakage. Dye penetration was measured by a milimetric ruler under stereomicroscope. For statistical analysis, Mann-Whitney test was used.The results showed that there was no significant difference in apical microleakage between experimental groups [p< 0.05]. Using calcium hydroxide as an intra-canal medicament has no negative effect on apical seal. Further leakage studies are suggested to confirm the results of the present study

in vitro study of the effect of immediate and delayed post space preparation with two different methods on apical seal

Nowadays, posts are widely used in the restoration of severely damaged teeth. They are considered resistant restorative features. The aim of this in vitro study was to evaluate the effect of immediate and delayed post space preparation with two different methods on apical microleakage. A total of 96 one-rooted extracted human teeth were used in this study. The crowns of the teeth were resected at the CEJ. Canal preparation was carried out by the step-back technique, in which file # 35 was chosen as MAF and the canals were flared up to file # 60. The canals were obturated with Gutta-percha and AH26 sealer using the lateral compaction technique. Then the teeth were randomly divided into 4 experimental groups, each containing 20 teeth and two positive and negative control group, each containing 8 teeth. In group A, a peeso reamer was used to prepare the post space immediately after canal obturation. In group B, the post space was prepared with a peeso reamer one week after canal obturation. In groups C and D a heat carrier was used to prepare the post space immediately and one week after canal obturation, respectively. Dye penetration technique was used to evaluate the microleakage. The liner measurement of dye penetration was carried out under a stereomicroscope and the data were statistically analyzed with ANOVA and LSD tests. The results of the study showed that group B [peeso reamer with delay] and group C [heat carrier with immediate] had the greatest and least dye penetration, respectively, demonstrating a statistically significant difference [p=0.03]. There was no statistically significant difference in dye penetration among other groups [p>0.05]. According to the results of the present study, the most appropriate time and procedure for post space preparation is immediately after canal obturation using a heat carrier

Root canal configurations of the maxillary first and second premolar teeth [in vitro]

As a cause of treatment failures, lack of a working knowledge of pulp anatomy ranks second only to errors in diagnosis and treatment planning. The purpose of this study was to investigate variations in the root canal system of maxillary first and second permanent premolar teeth. In this study, 188 maxillary first premolars and 138 second premolars, after access cavity preparation, the teeth were decalcified by 5% Nitric acid, dehydrated, cleared using Methyl salysilate, dye-injected and studied. The results showed that 6.38% of maxillary first premolars had one canal, 90.43% had two canals and 3.19% had three canals, and also 50% of maxillary second premolars had one canal and 50% had two canals. The first and second maxillary premolars should always be considered as having two root canals, unless Other wist is Proved, and also first maxillary premolars with three canals should be considered