Journal of Islamic Dental Association of IRAN
Volume:32 Issue: 3, Summer And Autumn 2020

Water/powder ratio is effective on some properties of irreversible hydrocolloid impression materials. This study aimed to determine the ef-fects of water/powder ratio of irreversible hydrocolloid impression materials on di-mensional stability of impressions.

In this in vitro experimental study, a metal model with two abutments as anchoring support for a three-unit dental bridge was used. Sixty alginate impressions were made with different water/powder ratios (control group and test group with 50% extra water). The impressions were made by acrylic trays. Alginate impressions were poured with dental stone after 15, 60 and 240 min of removal from the model. The diagonals and heights of the small and large dies as well as the outer space between the two dies were measured trice using a digital caliper with 0.01 mm accuracy, and the mean values were reported. The obtained dimensions were com-pared with each other and with the model. Data were analyzed by one-way ANOVA, one-sample t-test, and independent samples t-test (α=0.05).

In the majority of dimensions in both the control and test groups, there was a significant difference in comparison with the metal model. The mean dimensions of casts did not show any significant difference between the two groups after 240 min (P>0.1).

Increasing the water added to alginate powder by 50% affected the di-mensional stability of the resulted casts. The time interval before pouring the cast had a significant effect on dimensional accuracy of the casts.

This study aimed to evaluate the microleakage of cervical res-torations with the use of a one-step self-etch adhesive after application of three differ-ent hemostatic agents.

In this in vitro study, 96 cervical cavities were prepared on 24 intact and 24 demineralized teeth. Forty-eight class V cavities with sound tooth substrate were assigned to groups 1 to 4, and 48 cavities with demineralized tooth substrate were assigned to groups 5 to 8. In groups 1 and 5, no hemostatic agent, in groups 2 and 6, Viscostat, in groups 3 and 7, Viscostat Clear, and in groups 4 and 8, tri-chloroacetic acid (TCA) were used. After composite resin filling and thermocycling, the teeth were immersed in dye, sliced, and dye penetration was scored under a mi-croscope. Data were analyzed with the Kruskal-Wallis and Mann-Whitney tests.

The mean enamel microleakage values were significantly different among the groups (P=0.027); however, there was no significant difference in the mean dentin mi-croleakage values between the study groups (P=0.072). Significant differences were also noted in enamel marginal leakage between groups 1 and 3, 1 and 5, 3 and 8, and 5 and 8 (P<0.05). No significant difference was observed in microleakage of groups with normal dentin and groups with simulated caries-affected dentin (P=0.063).

Within the limitations of this study, Viscostat Clear exhibited the greatest enamel microleakage. There were no significant differences in dentin microleakage between the study groups; however, among the groups with simulated caries-affected dentin, TCA showed lower microleakage.

Facial features are different depending on gender and race. These features are usually studied in profile view. Angular evaluation of the facial soft tissue profile is important in males and females of different races for correct diagnosis and treatment planning. For this reason, in the present study, we measured the facial profile angles in young adults in Zanjan.

In this descriptive cross-sectional study, the photographs of 35 males and 35 females between 16 to 30 years were studied. The patients had class I malocclusion without a history of trauma, plastic surgery, or previous orthodontic treatment. Using AutoCAD software (version 2015), 12 angles were meas-ured on the facial profile view photographs. Student t-test was used for statistical analysis.

There were significant differences between males and females in four angles namely the nasal angle, angle of the nasal dorsum, angle of the inferior facial third, and angle of facial convexity (P<0.05). The nasal angle in females was larger than that in males, but the angle of the nasal dorsum, angle of the inferior facial third, and angle of facial convexity were wider in males. Other angles did not show any sig-nificant difference between males and females.

In the present study, soft tissue facial measurements were performed by means of photogrammetric analysis to help orthodontists carry out quantitative eval-uations and make disciplined decisions. The mean values obtained can also be used for studies comparing the records of participants with the same characteristics in other ethnicities.

The aim of this study was to evaluate the micro-shear bond strength of an indirect composite resin to three different types of cores.

In this in-vitro study, 14 blocks (5×5×2 mm) were designed and milled by computer from cobalt-chromium (Co-Cr) alloy, zirconia, and polyether ether ketone (PEEK). Each sample was treated according to the manufacturer’s instructions, and the appropriate primer, and a layer of Crea.lign opaquer were applied on the surface. For micro-shear bond strength test, a plastic tube with an internal diameter of 1 mm and height of 2 mm was placed on each block, and Crea.lign paste was condensed in it. The Crea.lign paste and opaquer were light-cured separately for 180 s, and finally for 360 s. All samples were placed in 37°C distilled water for 24 h and thermocycled for 5000 cycles (5 to 55°C). The microtensile tester machine was used to measure the micro-shear bond strength. The samples were also evaluated for failure modes. Data were analyzed using one-way ANOVA (P<0.05).

According to one-way ANOVA, the mean micro-shear bond strength (MPa) in Co-Cr alloy, zirconia, and PEEK groups was 25.19±5.53, 23.49±5.48, and 20.58±5.68 MPa, respectively. There was no significant difference in micro-shear bond strength of the three groups (P= 0.099). The most frequent mode of failure in all three groups was adhesive, followed by mixed, and cohesive.

Applying the standard procedure, type of core material had no significant effect on the micro-shear bond strength of Crea.lign composite veneer.

Considering the critical role of inflammatory responses in periodontal disease, knowledge about the immune system and cytokines seems nec-essary. The aim of this study was to evaluate the level of IL-23 and IL-17 in gingival crevicular fluid (GCF) of patients with chronic and aggressive periodontitis, before and after non-surgical periodontal therapy.

In the present clinical trial, GCF samples were collected from 54 patients (with aggressive and chronic periodontitis) before and after the ini-tial phase of periodontal therapy. The cytokine concentration was measured using ELISA. The Wilcoxon signed-rank test was performed to analyze the effect of non-surgical periodontal therapy on each group. The correlation between variables was investigated by the Spearman’s correlation coefficient.

Non-surgical periodontal therapy in both groups significantly decreased the IL-17 and IL-23 levels (P<0.05). A significant correlation was noted between the con-centration of IL-23 and IL-17 before the treatment in the chronic periodontal group (P<0.05), while such a correlation was not seen in the aggressive periodontitis group (P>0.05).

Due to the reduction of IL-17 and IL-23 after nonsurgical periodontal therapy, these factors may play a role as mediators of periodontitis pathogenesis. Di-rect statistical correlation between the concentration of IL-17 and IL-23 before treat-ment in the chronic group shows the possible role of IL-23 in inducing Th-17 cells and production of IL-17.

High blood pressure is a common cardiovascular disease. Most cardiovascular medications have adverse oral side effects. This study aimed to determine the prevalence of oral manifestations associated with the intake of anti-hypertensive medications.

This cross-sectional analytical study examined 142 patients with a history of hypertension referred to Dr. Heshmat Hospital in Rasht who were taking one of the four drug categories of diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or beta-blockers. The patientschr('39') demographic information, medications, and oral symptoms such as mucosal burning, xerostomia, angioedema, and lichenoid reactions were recorded. The data were analyzed by SPSS version 24 using Fisher’s ex-act test and Chi-square test (P<0.05).

From 142 participants, 103 were males and 39 were females; 58.4% of the participants were 61 years or older. Concomitant use of beta-blockers and angiotensin receptor blockers (especially metoprolol and losartan) had the highest frequency among patients. Xerostomia was the most common side effect; angioedema was not reported in any patient. The prevalence of xerostomia increased with age (P=0.044) but it was not correlated with gender (P=0.119). Lichenoid reactions and burning mouth were neither age-related nor gender-related (P>0.05 for all).

Oral complications are inevitable in patients taking anti-hypertensive medications, and in most cases it is not possible to change or decrease the dosage of medications. Therefore, regular dental examinations and palliative treatment can play a role in improving the patientschr('39') quality of life.