Journal of Dental Medicine
Year:2013 | Volume:26 | Issue:3 (76)|Papers Count:11

Background and Aims: The purpose of this study was to evaluate the tissue responses to Octacalcium phosphate (OCP) and calcium hydroxide (CH) used as direct pulp capping (DPC) materials in cat teeth.Materials and Methods: 72 premolar teeth of 9 cats were selected and divided into 3 groups (Two experimental and one control group). After the cats had been anesthetized, the teeth were exposed and capped directly with OCP, CH or no capping material as control group. The cavities of all three groups were filled with Glass ionomer cement (GI). Histological evaluations were performed at two, four and eight weeks after pulp capping. After tissue preparation procedures, paraffin blocks were prepared. After preparation and staining of the sections, the relevant variables were measured by optical microscope. The results were analyzed using Mann-Whitney U and Chi-square tests (a=0.05).Results: Two weeks after pulp capping, all specimens in three groups showed mild to sever inflammation. The formation of hard tissues (dentinal bridge) initiated in the exposed areas of the experimental groups was more noticeable for calcium hydroxide than that of octacalcium phosphate group, These differences were statistically significant (P<0.001). At four weeks, hard tissues were observed in both groups which were more evident for the CH group and there were statistically significant differences between two experimental groups (p<0.003). At eight weeks, continuous hard tissues were observed in both groups and there were no statistically significant differences between them (P>0.05), but hard tissues continuity were better for in the OCP than that of the CH.Conclusion: It seems that the formation of hard tissue in CH because of its porosities had a worse percentage in sealing of the pulp than the OCP.

Background and Aims: The purpose of this study was research on a new herbal compound (Seidlitzia Rosmarinus) made by Traditional Medicine Research Group, University of shahed to find a safer alternative to HCL-Pumice compound technique.Materials and Methods: In this randomized clinical trial seventy two teeth from 9 patients were divided in to three groups according to fluorosis severity: mild (34 teeth), moderate (14 teeth), and sever (24 teeth). In each patient, half of the teeth were treated with “Shahed” compound and other half treated with HCL-Pumice compound. Before and after treatment, photographs were taken in both groups. HCL-Pumice treatment compound was applied for 30 seconds periods and continued for 10 minutes if necessary. In case of herbal Shahed compound the time was determined by clinical symptoms or when labial contour was dismissed, If the result was not esthetistically acceptabale for the patient, HCL-Pumice compound was applied on teeth. NaF was applied after mouth washing. The photographs of the teeth before and after treatment were reviewed by two experienced observer unaware of the treatment modality. The results were analyzed using willcoxon wallis, kruskal and scheffe' test. Results: There was over 81.3% acceptance between two observers and no significant differences in intraobservers evaluation (P>0.05). Improvement in beauty indexes were observed in all degrees of dental fluorosis by 18% with HCL-Pumice compound application, but “Shahed” herbal compound induced significant reduction in the amount of white spots in mild fluorosis and stain intensity of moderate fluorosis (P<0.05), While the reduction in the severity of discoloration in group 2, these two techniques were statistically equivalent but in the remainder, HCL-Pumice compound was more significantly effective (P<0.05).Conclusion: HCL-Pumice compound reduces the severity of the discoloration of the teeth. Shahed herbal compound cannot reduces the discoloration like as HCL-Pumice compound.

Background and Aims: Along with the advances in dental material and invention of new techniques of producing ceramics, the demand for the beauty and matching restoration's color with patient's natural teeth is growing. Nowadays, zirconia systems are the focus of attention. Despite their strength, one of the problems of such systems is high opacity and failing to provide the favored color. Considering few studies about the influence of shading on Zirconia, the purpose of this in vitro study was to evaluate the effect of different shading of zirconia-based ceramics on the biaxial flexural strength.Materials and Methods: In this in vitro experimental study, Rainbow (Dentium, Korea) zirconia-based ceramics (the diameter of 15mm and 1mm in thick) were divided into four groups of 10 specimens. According to Vita shade guide system and manufacturer's time recommendations (3 seconds), three groups of disc specimens were shaded to A3, B3 and D3 colors and other ten specimens remained uncolored as control group. The biaxial flexural strength test of discs was evaluated, and with the EDX analysis system the elements' composition available in colors was detected. Finally, data were analyzed using one-way ANOVA and Post-hoc tests.Results: The biaxial flexural strength in non colored specimens, A3 shaded discs, B3 shaded, and D3 shaded specimens were determined 1061.93, 819.16, 1100.10, and 825.48 MPa respectively which was statistically significant among groups (P<0.001). The statistical analysis revealed that the highest strength in B3 and non colored groups which were significantly higher than A3 and D3. EDX analysis showed significant differences among different colored compositions.Conclusion: The biaxial flexural strength of zirconia cores are affected by shading and the specific selected color.

Background and Aims: Different adhesives with different solvents may have different solvent evaporation rates. The purpose of this study was to evaluate the solvent evaporation in the self etch and total etch adhesive in different air drying times. Materials and Methods: Five adhesives were used in this study: Excite, Prime & Bond NT, UNO, Single Bond, SE Bond Primer. Twelve drops of each adhesive were used for each period of air drying (5, 15, 30 sec). The percentage of mass loss was measured during each test. Data were analized using two-way ANOVA and Tukey. Results: Acetone base adhesives showed more loss of mass than other adhesives (P<0.01). P&B NT showed more loss of mass than other adhesives in all air drying times (P<0.01). Adhesives showed different evaporation rates in different air times (P<0.01). Conclusion: Adhesives with acetone/water or alcohol/water solvent shows more stable behavior in comparison with adhesives containing pure aqueous solvents.

Background and Aims: Oral health prepares us for daily activities without discomfort, and dissatisfaction. In this research, agreement level between parents and children aged 11-14-year-old in reporting child oral health-related quality of life was studied in Isfahan city.Materials and Methods: In this descriptive, analytical and cross-sectional study 128 pairs of parents and children aged 11-14 were selected with random sampling technique from schools in Isfahan and were asked to complete the relevant questionnaires. The questionnaires evaluated quality of life in four fields of oral signs, functional deficits and emotional and social health. In order to evaluate child-parent agreement, intra-correlation coefficient (ICC), Pearson's correlation coefficient, Spearman's correlation coefficient and intra-class correlation coefficient (ICC) were used (a=0.05).Results: The agreements between PPQ11-14 (parent perception questionnaire), CPQ11-14 (child perception questionnaire) and the related fields were 0.81, -0.67. The highest agreement level (ICC=0.83) was related to emotional health (excellent), followed by functional deficits (ICC=0.80), social health (ICC=0.69) and oral signs (ICC=0.64). Pearson's test showed significant correlations between CPQ11-14 and PPQ11-14 (r=0.81) (P<0.01).Conclusion: Although parents, especially mothers, may be used as proxies for their children in relation to quality of life and related fields, the views of both should be obtained in order to fully represent child oral health-related quality of life issues.

Background and Aims: Bleaching agents not only affect the tooth structure, but also may alter the properties of restorative materials. The aim of this in vitro study was to evaluate the effect of different bleaching regimens on the microhardness of four tooth-colored restorative materials.Materials and Methods: Eighty specimens of four restorative materials (Microhybrid resin composite (Z250 (3M, ESPE), nanohybrid composite Z350 (3M, ESPE), packable composite P60 (3M, ESPE), and resin modified glass ionomer Vitremer (3M, ESPE)) were fabricated and were polished after 24 h with Soflex discs (3M, ESPE). Then the specimens were divided into two groups: In office bleach group, 40 specimens (10 of each restorative material) were bleached with hydrogen peroxide 37.5% for 30 min in two sessions with 7 days interval. In home bleaching group, 40 specimens were bleached with carbamid peroxide 22%, 6 h a day for 14 days. Vickers microhardness test were done before and after bleaching (baseline). Finally data were evaluated using analysis of Variance.Results: Two bleaching regimens were significantly decreased the microhardness values. In Z250 resin composite, the microhardness values before and after bleaching were 95.30 and 92.67 kg/mm2, respectively. for office bleaching (P=0.011) and 95.38 and 92.39 kg/mm2 for home bleaching (P<0.001). In Z350 resin composite, the microhardness values before and after bleaching were 98.29 and 92.41 kg/mm2, for office bleaching (P<0.001) and 97.35 and 93.44 kg/mm2 for home bleaching (P<0.001) respectively. In P60 resin composite, the microhardness values before and after bleaching were 103.10 and 96.16 kg/mm2, respectively. for office bleaching (P=0.045) and 102.61 and 98.16 kg/mm2 for home bleaching (P=0.001). In resin modified glass ionomer (Vitremer), the microhardness values before and after bleaching were 56.79 and 49.41 kg/mm2, respectively. for office bleaching (P=0.004) and 54.17 and 46.50 kg/mm2 for home bleaching (P<0.001). There was no significant difference between two bleaching agents (P=0.365).Conclusion: Dental bleaching agents decrease the microhardness of tooth-colored restorative materials.

Background and Aims: Successful root canal therapy requires knowledge of tooth anatomy and root canal morphology. For permanent mandibular premolars, great variety in size, shape and number of roots and root fusion expression has been reported in the literature. There is a wide variety of methods used in studies for evaluating the root canal morphology. One of these methods is Cone-bean Computed tomography (CBCT) that reduces the limitations of two-dimensional X-ray image and with less exposure in comparison with other 3D radiographies. Thus, this study was designed to evaluate the differences in the root and canal morphology of permanent mandibular premolars in an Iranian population by means of CBCT images.Materials and Methods: We searched a database of CBCT scans and evaluated 400 (20-60 years old) patients who met the inclusion criteria and teeth in this images (CBCT) were evaluated in three dimensions (Axial, Coronal and Sagital). Tooth length, number of roots, number of canals, canal type, root curvature and the effect of gender on any of the items mentioned were evaluated. Data were analyzed using T-test.Results: The average length of the first premolar of mandibular was 22.27 mm and second premolar was 22.28 mm. 98.4% of the first premolar and 98.2% of the second premolar were single root., and 87.3% and 93.1% were single channel. The incidence of number of canals based on vertochy divisions were: type 1: 90.7% and 90.8%, type 0: 2.2% and 2.8%, type 4: 3.3% and 3.1%, type 6: 1.4% and 2.1% and type 3: 2.5% and 1.5% respectively. In any case, there was no significant difference between males and females (p<0.001).Conclusion: Results indicates that dentists can obtain valuable information about the anatomy and morphology of the root canals using CBCT.

Background and Aims: Metallic nano-particles show exclusive biological, chemical and physical characteristic.The purpose of this research was to evaluate the effect of various amounts of nanosilver incorporation (0 (as control), 20, 40, 80, 120, 200 ppm) on the mechanical Properties (compressive and flexural strength) of resin modified Glass ionomer Cement.Materials and Methods: Based on ISO 4049 and ISO 9971 for polyalkenoid cements, 90 cases in each group were prepared for the flexural and compressive strength. Specimens in 6 groups with different amounts of nanosilver (20, 40, 80, 120 and 200 ppm) and control (Fuji II LC improved), stored in distilled water at 37oC for 1 day and 30 days. Flexural strength, using a three-point bending method, Modulus of elasticity and the compressive strength were measured by universal testing machine (Zwick) with crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey post HOC test.Results: The flexural strength and modulus of various amounts of nanosilver incorporation of resin modified glass-ionomer cement were not significantly different (P>0.05). The compressive strength of incorporating of 20 ppm compared with control (P=0.01), 40 ppm (P=0.02) and 80 ppm compared with control (P<0.001) were increased. The flexural strength and compressive strength of Fuji II LC, containing nanosilver particles were increased after 1 day and 1 month significantly (P<0.001).Conclusion: Incorporation of 20 to 80 ppm nanosilver into Fuji II LC had increased mechanical properties compared to the original cement.

Background and Aims: Iatrogenic damage to adjacent tooth during proximal cavity preparation is one of the most common side effects in operative dentistry. The aim of this study was to determine prevalence of iatrogenic damages to adjacent tooth during the preparation of proximal Class II cavities among undergraduate students at dental faculty of Tehran University of Medical Sciences in 2010.Materials and Methods: 106 posterior permanent teeth which had Class II decay with sound proximal surfaces of adjacent teeth were selected and restored by dental students awarding the aims of the present study. After finishing restoration, proximal surfaces were completely dried by air and evaluated with dental chair light. In doubtful cases, surfaces were evaluated with×3 magnification. Damages were classified into 2 groups, abrasion and groove. Data were analyzed using Fishers exact and Pearson chi square tests.Results: The frequency of adjacent surfaces damage were 57.5%, with 31.1% damages as abrasion and 26.4% as groove. Students who used matrix band and wedge in proximal area as preventive instruments showed 53.4% damages and other students showed 57.3% damages (P>0.05). A significantly higher number of females and students at restorative course level (3) used wedge and matrix band than males and students at restorative course level (4) for protecting adjacent teeth (P<0.05).Conclusion: According to the high percentage of iatrogenic damages on adjacent sound teeth in class II cavity preparation, teaching of preventive methods and using proper techniques is necessary for dental students as future dentists.

Untreated caries are common findings in low-income communities. Treatment of dental caries in young children is challenging and requires a high skill and high cost of dental anesthesia for controlling patients and thus, chemical methods for arresting dental caries have been proposed. Silver diamine fluoride (SDF) is a material that is used to control and to arrest dental caries, especially in primary teeth. It is noninvasive, safe, easy to use, and cost-effective. The SDF can be used as a therapeutic agent in oral health projects in low-income communities. In this article we reviewed the silver diamine fluoride and its application in dentistry.