JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2010 | Volume:22 | Issue:3 (76)|Papers Count:11

Background and Aim: Skeletal anchorage devices such as microimplants are successful attempts to have absolute anchorage. The aim of this study was to evaluate the effect of immediate and delayed orthodontic loading on maxillary and mandibular microimplants regarding histologic responses and bone implant contact (BIC) in a dog.Materials and Methods: Thirty-two microimplants (Abso Anchor) were bilaterally placed in the mandibular premolar regions of four adult male dogs. The microimplants were divided into loaded and unloaded (control) groups. The control group had two subgroups of 4 and 8 weeks and the loaded group comprised two subgroups of immediate and delayed (after 4 weeks healing period) loading. Loaded samples were subjected to 200g load provided by Ni-Ti coil spring for 4 weeks. The decalcified specimens were prepared for histological examination under light microscope. The microimplants’ surrounding tissue was observed histologically and the bone implant contact (BIC) percentage was calculated in each sample. Three ways ANOVA was used to compare BICs in different groups.Results: Mobility was detected in two mandibular microimplants, so the survival rate was calculated as 93.7%. BIC values were not significantly different between loaded and unloaded groups, and between immediate and delayed loaded groups.Conclusion: Immediate or delayed loading of microimplants does not lead to significant difference in the bone-microimplant contact.

Background and Aim: Dry mouth or xerostomia is a major complaint of many elderly individuals especially in menopause. The exact mechanisms that mediate xerostomia have not been firmly established. The aim of this study was to investigate the serum cortisol level in menopausal women with dry mouth.Materials and Methods: A case-control study was carried out on 96 selected menopausal women aged 42 to 77 years with or without dry mouth (48 as case and 48 as control) conducted at the clinic of oral medicine, Tehran university of medical sciences. Serum concentration of cortisol was assessed by enzyme-linked immunosorbent assay (ELISA). Statistical analysis of Student’s unpaired t-test was used.Results: The mean concentration of serum cortisol was significantly higher in the case group (109.2±5.5 ng/ml) compared to the control group (93.1±5.4 ng/ml) (P<0.05).Conclusion: The results showed that subjects with dry mouth had an increased serum level of cortisol compared with those without this symptom, which suggests an association between cortisol and symptoms of oral dryness.

Background and Aim: Fluoride has popularly been used as a caries prevention agent. This study evaluates the effect of fluoride gel (APF) on microleakage before and after restoration placement of tooth colored restorations.Materials and Methods: Eighty-four standard class V cavities were prepared and the specimens were randomly divided into three groups (n=14): Group 1- APF employed before cavity preparation; Group 2- APF employed after completed restoration; Group 3- without APF application (control). Buccal cavities were restored with OptiBond Solo adhesive system and Herculite XRV composite resin and lingual cavities were restored with Fuji II LC Glass ionomer. After finishing and polishing, thermal cycling followed by immersion in 0.5% basic fuchsin dye was performed. Then, the specimens were sectioned and microleakage was ranked under magnification (×40). Two teeth of each group were treated for SEM observation. Data were subjected to statistical analysis using Kruskal Wallis and Wilcoxon tests.Results: There were significant differences in enamel marginal microleakage of composite (14.68) and glass ionomer (16.00) restorations (p=0.02), but they similarly proceeded in dentinal margins (0.921). The dentinal margins (2.50) of the glass ionomer in control group showed more leakage than the enamel margins (0.00) (p=0.04). All experimental groups; either before or after fluoride therapy, showed similar microleakage in the enamel and dentinal margins.Conclusion: APF employed was ineffective on microleakage before and after composite resin restoration placement. Microleakage could increase in enamel margins of resin modified glass ionomer restorations with fluoride therapy protocol.

Background and Aim: The infection transmission by impressions to the laboratory is growing concern for clinicians and laboratory technicians. This study aimed to compare the self-antibacterial effect of six irreversible hydrocolloid impression materials (Iralgin, Xantalgin, Tropicalgin, Plastalgin, Hydrogum and Orthoprint) on oral flora microorganisms.Materials and Methods: In this experimental set-up, 108 irreversible hydrocolloid specimens including alginate disks with 1 mm thickness, 5 mm diameter and 30±2 mg weight, and 18 sterile paper disks as negative control specimens (totally 126 specimens) were prepared. These specimens were transferred to Staphylococcus aureus (Group 1), Pseudomonas aeruginosa (Group 2) and Candida albicans (Group 3) fresh microbial environments. After 48 hours incubation in 37 degrees Celsius, the maximum growth inhibition zone diameters were recorded. Statistical analysis was performed by ANOVA or Friedman test.Results: No zone of inhibition was observed around the control specimens. Iralgin and Tropicalgin specimens had significant growth inhibition on Group 1. Tropicalgin more than Iralgin and Iralgin more than the other specimens significantly inhibited Group 2 microorganisms. Plastalgin specimens had significant growth inhibition on Group 3 (P<0.05).Conclusion: Some of the investigated alginates had self-antibacterial effects; however, disinfection of impressions with other techniques are still inevitable.

Background and Aim: Tea contains high concentrations of fluoride; therefore, tea consumption may contribute significantly to the total fluoride intake. Since different teas contain various amounts of fluoride, this study was conducted to compare the fluoride extraction of four popular domestic and foreign tea brands using spectrophotometric and ionic chromatography methods.Materials and Method: In this study, two foreign black tea brands (Lipton and Ceylon) and two domestic tea brands (Golestan and Mozafar) were selected. Three packages of each tea brand with the same production date and different batch types were purchased. To each 4 g of dried tea, 100 ml of boiling deionized water was added and the mixture was left on a water bath for the extraction of fluoride for 20 minutes at 85oc and then analyzed with spectrophotometric and ionic chromatography methods. ANOVA, Duncan and paired t tests were used for statistical analysis.Results: All four tea infusions had a considerable fluoride concentration (2.7-4.44ppm, using ionic chromatography and 2.77-4.38ppm using spectrophotometry). There was a significant difference between the fluoride concentration of these four tea brands (p<.05), of which Lipton had the highest floride concentration. Based on this research, there was no significant difference between spectrophotometry and ionic chromatography methods in determining the concentration of fluoride ions.Conclusions: The mean fluoride concentration in Lipton tea was significantly higher than the other brands. There was no significant difference between spectrophotometric and ionic chromatography.

Background and Aim: Different rotary NiTi systems have been introduced for root canal cleaning. This study was performed to compare the effectiveness of a manual file (K file) with two rotary systems (ProTaper and Mtwo) for root canal preparation in the first permanent molar teeth.Materials and Methods: India ink was injected to 140 of 150 mesiobuccal root canals of human mandibular first permanent molars, which were randomly divided into three experimental (including 40 canals) and three control groups (10 canals). In each of these first, second and third subgroups, either the manual instrument (K-file) or the rotary system (ProTaper and Mtwo) were used to prepare the root canals. Canals in group 4 were irrigated with normal saline. In group 5 and 6 no instrumentation was performed. After clearing the teeth, the root canals were observed with the help of a stereomicroscope and the data were analyzed by SPSS, Kruskal-Wallis and Friedman tests (p<0.05). Results: There was no significant difference between manual and rotary instruments. There was a significant difference between cleaning of the apical, middle and coronal areas of the canals prepared with K-file with a better performance at the apical area compared with the coronal and middle parts. While there were no significant differences in any of the three root canal regions using ProTaper or Mtwo systems.Conclusion: The ProTaper and Mtwo rotary systems showed acceptable cleaning ability and efficacy in permanent molar root canals.

Background and Aim: It seems that different growth mechanisms and biologic behaviors of odontogenic cysts are related to different expressions of various proteins and molecules. The purpose of this study was to determine the expression of p53 and ki-67 in radicular cysts (RC), odontogenic keratocysts (OKC), inflamed (IDC) and noninflamed dentigerous cysts (NIDC).Materials and Methods: In this cross-sectional descriptive study, 13 RCs, 10 NIDCs, 15 IDCs and 19 cases of OKC were selected and stained for p53 and ki-67. The slides were evaluated by light microscopy (x400 magnification) and brown-staining cells were counted. Data were analyzed by Mann-Whitney and Kruskal Wallis tests.Results: P53 expression was not observed in any cases of RCs and NIDCs. This marker was seen in 6.7% of IDCs and 57.9% of OKCs with an average of 0.27±1.03 and 17.31±27.68. There was a statistically significant difference between OKC and other cysts regarding the expression of this marker (p=0.006). Ki-67 expression was observed in 84.6%, 73.7%, 66.6% and 44% of RCs, OKCs, IDCs and NIDCs, respectively. A significant difference existed between OKC and NIDC, and also NIDC and IDC (p=0.048) and radicular cysts and inflamed dentigerous cysts (p=0.046).Conclusion: Based on the results of this study, expression of p53 and ki-67 is related to clinica l behavior and growth potential of odontogenic cysts.

Background and Aim: Different studies have demonstrated that resin penetration into collagen fibers is influenced and promoted by the presence of a solvent in the bonding agents, but in order to create a reliable bond, it should be removed before curing. This study investigates the effect of adding ethanol as a solvent on the microshear bond strength of a solvent-free dentin bonding agent.Materials and Methods: After removing the occlusal enamel of 20 caries-free human third molars, midcoronal dentin slices, each about 2 mm thick were prepared then polished by silicon paper. The superficial dentin surfaces were randomly distributed into four groups and treated with James-2 containing different concentrations of ethanol (0, 5, 10, and 20 wt%) in two layers and then light-cured. The micro shear bond strength (µSBS) was tested using a universal testing machine. The data were finally subjected to one-way ANOVA followed by Tukey's post-hoc test.Results: James-2 containing 5 wt% ethanol provided the highest micro-shear bond strength (32.1±6.69 MPa). There were no statistical differences in µSBS values between other groups (25±5.8 MPa, 24.8±4.93 MPa and 21.8±4.51 MPa, respectively).Conclusion: Adding ethanol as a solvent resulted in increased micro shear bond strength to dentin. At higher solvent concentrations no significant change was observed indicating that the solvents may not have been completely removed leading to poor polymerization and porosity reflected as lower bond strengths.