فهرست مطالب
Frontiers in Dentistry
Volume:13 Issue: 4, Jul 2016
- تاریخ انتشار: 1395/05/05
- تعداد عناوین: 10
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Pages 223-230ObjectivesTo assess the effect of lactic acid (LA) on microleakage of silorane-based composite restorations and methacrylate-based composites with self-etch and etch-and-rinse bonding systems.Materials And MethodsClass V cavities were prepared in 120 extracted human teeth, divided into four groups and restored as follows: 1. Silorane-based composite㿝 adhesive system (P90); 2. Filtek Z250 Bond (Z250SE); 3. Filtek Z350 Bond (Z350SE) and 4. Filtek Z250䨩 Bond (Z250SB). Half of the samples in each group were immersed in LA and the other half in distilled water (DW) for seven days. Degree of microleakage was determined by dye penetration. Data were analyzed using Kruskal Wallis and Mann Whitney-U tests (type 1 error was considered 0.05 for primary and 0.017 for post-hoc tests).ResultsNo significant difference was found in microleakage between LA and DW groups. The difference among groups in gingival margin microleakage was significant (PConclusionsImmersion in LA has no effect on microleakage of class V composite restorations regardless of the type of composite and adhesive system. At gingival margins, the highest microleakage occurred in Z250SB followed by P90 and self-etch groups.Keywords: Silorane Composite Resin, Dental Leakage, Lactic Acid
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Pages 231-237ObjectivesThis study aimed to evaluate the effect of chlorhexidine (CHX) application protocol on durability of marginal seal of class V composite restorations.Materials And MethodsClass V cavities (4×2×1.5mm) were prepared in the buccal surfaces of 160 human third molars. The teeth were randomly divided into five groups (n=32) of (G1) CHX긩爘, (G2) CHX竗↊, (G3) etchingࡵﺮ⧬, (G4) etching CHX, and (G5) etching alone as the control group. Adper Single Bond 2 was applied as an etch and rinse (E & R) bonding system. Cavities were filled with Z350 composite. Half of the teeth in each group were stored in distilled water for 24 hours and the other half were thermocycled (10,000 cycles, 5-55˚C). For dye penetration test, the teeth were sectioned buccolingually and assessed at the enamel and dentin margins under a stereomicroscope at ×20 magnification. The Kruskal-Wallis, Dunn and Mann-Whitney tests were used for statistical analyses.ResultsThere was no significant difference in immediate microleakage among the groups at the enamel and dentin margins (P= 0.894). After thermocycling, there was significantly less microleakage in G4 than the control group at dentin margin. There were significant differences in microleakage between G4 and G1(P=0.002), G4 and G2 (P=0.001) and G4 and G5 (P= 0.001) at dentin margin.ConclusionsApplication of CHX after etching without rinsing is effective to decrease microleakage. However, it has no effect if applied before etching in use of this particular type of E & R adhesive after thermocycling.Keywords: Dental Leakage, Chlorhexidine, Composite Resins
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Pages 238-243ObjectivesAsthma is a common chronic disease. Asthma and anti-asthmatic medications have been suggested as risk factors for increased susceptibility to caries. This study was conducted to evaluate the effects of different types and forms of antihistaminic medications and the duration of drug consumption on the severity of dental caries in asthmatic children.Materials And MethodsThis cross-sectional study was conducted in Asthma and Allergy Department of Childrens Medical Center in Tehran, Iran. Eighty-five children between three to 12 years who had been diagnosed with asthma, by means of taking medical history, clinical examination and spirometry were chosen by non-simple random sampling. The participants and their parents were interviewed. Oral examination was performed by a qualified dentist. The data were collected by use of questionnaires and analyzed by the stepwise multivariate linear regression analysis, using SPSS version 16. PResultsThere was a significant correlation between the number of cetirizine and ketotifen tablets taken and decayed/missing/filled (dmf/DMF) teeth score (P=0.006). There were no correlations between the number of consumed sprays and dmf/DMF score (P=0.923), the duration of drug therapy (P=0.907) or the type of medication taken including ß2 agonists, antihistamines, steroids or a combination of them (P=0.907).ConclusionsThe present study showed that the tablet form of medications significantly increased the severity of dental caries even in presence of confounders (sex, age, duration of disease, tooth brushing, sugar consumption, fluoride therapy, mouth dryness).Keywords: Asthma, Anti, Asthmatic Agents, Dental Caries
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Pages 244-251ObjectivesA reduction in bond strength of composite to bleached enamel has been reported immediately after bleaching treatment. Application of some antioxidant agents may decrease the adverse effects of whitening agents on bond strength and enhance composite bond to enamel. This study aimed to assess the effect of green tea, sodium ascorbate, sage and grape seed extract on bond strength of composite to bleached enamel.Materials And MethodsIn this in-vitro study, 90 human enamel surfaces were randomly divided into six groups as follows (n=15): G1, no bleaching; G2, bleaching with 40% hydrogen peroxide (HP); G3, HP흍 μmol epigallocatechin gallate (EGCG) for 10 minutes; G4, HP% sodium ascorbate for 10 minutes; G5, HP% sage for 10 minutes and G6, HP% grape seed extract for 10 minutes. The specimens were bonded to composite in all groups. The shear bond strength of specimens was measured in Megapascals (MPa). Data were analyzed using one-way ANOVA and Tukeys HSD test (α=0.05).ResultsThe highest and the lowest mean shear bond strength values were observed in group 1 (22.61±3.29MPa) and group 2 (5.87±1.80MPa), respectively. The reduction in bond strength in group 2 was greater than that in other groups (P0.05).ConclusionsAll the herbal antioxidants used in this study equally compensated for the reduced bond strength of composite to bleached enamel.Keywords: Antioxidants, Tooth Bleaching, Composite Resins, Shear Strength
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A Comparison of Radiographic Film Densitometry Using a New Computerized Tool with a Digital DensitometerPages 252-260ObjectivesThe purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge.Materials And MethodsWe reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mmx3mx10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer.ResultsThe new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new methods sensitivity in determining density changes was 5.26%, 84.1% and 93.02% in steps 2, 7, and 12 respectively.ConclusionsOur new method has an acceptable sensitivity for determining density changes of at least 7 mmEq/Al.Keywords: Densitometry, Image Processing, Computer, Assisted, Aluminum, Phantoms, Imaging
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Pages 261-270ObjectivesThis study aimed to assess the effects of two energy drinks on color change (∆E) of two methacrylate-based and a silorane-based composite resin after one week and one month.Materials And MethodsThirty cubic samples were fabricated from Filtek P90, Filtek Z250 and Filtek Z350XT composite resins. All the specimens were stored in distilled water at 37°C for 24 hours. Baseline color values (L*a*b*) of each specimen were measured using a spectrophotometer according to the CIEL*a*b* color system. Ten randomly selected specimens from each composite were then immersed in the two energy drinks (Hype, Red Bull) and artificial saliva (control) for one week and one month. Color was re-assessed after each storage period and ∆E values were calculated. The data were analyzed using the Kruskal Wallis and MannWhitney U tests.ResultsFiltek Z250 composite showed the highest ∆E irrespective of the solutions at both time points. After seven days and one month, the lowest ∆E values were observed in Filtek Z350XT and Filtek P90 composites immersed in artificial saliva, respectively. The ∆E values of Filtek Z250 and Z350XT composites induced by Red Bull and Hype energy drinks were not significantly different. Discoloration of Filtek P90 was higher in Red Bull energy drink at both time points.ConclusionsProlonged immersion time in all three solutions increased ∆E values of all composites. However, the ∆E values were within the clinically acceptable range (Keywords: Color, Composite Resins, Energy Drinks, Silorane Composite Resin, Spectrophotometry
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Pages 271-278ObjectivesStem cell (SC) therapy is a promising technique for tissue regeneration. This study aimed to compare the viability and proliferation ability of periodontal ligament stem cells (PDLSCs) isolated from the periodontium of healthy and periodontitis-affected teeth to obtain an autologous, easily accessible source of SCs for tissue regeneration in periodontitis patients.Materials And MethodsThe PDLSCs were isolated from the roots of clinically healthy premolars extracted for orthodontic purposes and periodontally involved teeth with hopeless prognosis (with and without phase I periodontal treatment). Cells were cultured and viability and proliferation ability of third passage cells in each group were evaluated using the methyl thiazol tetrazolium assay. The results were statistically analyzed using t-test.ResultsNo SCs could be obtained from periodontitis-affected teeth without phase I periodontal treatment. The viability of cells was 0.86±0.13 OD/540 in healthy group and 0.4±0.25 OD/540 in periodontitis-affected group (P=0.035). The proliferation ability (population doubling time) of cells obtained from healthy teeth was 4.22±1.23 hours. This value was 2.3±0.35 hours for those obtained from periodontitis-affected teeth (P=0.02).ConclusionsViability and proliferation ability of cells isolated from the periodontium of healthy teeth were significantly greater than those of cells isolated from the periodontitis-affected teeth.Keywords: Stem Cells, Periodontitis, Tooth, Regeneration
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Effect of Voxel Size and Object Location in the Field of View on Detection of Bone Defects in Cone Beam Computed TomographyPages 279-286ObjectivesThis study aimed to assess the effect of voxel size and object location in the field of view (FOV) on diagnostic accuracy of cone beam computed tomography (CBCT) for detection of simulated bone defects.Materials And MethodsIn this in vitro study, bone defects were drilled in four sections of a dry human mandible. Bone blocks were fixed on a platform parallel to the horizontal plane and CBCT images were acquired using 0.2mm and 0.3mm resolutions and five locations of FOV (anterior, posterior, left, right and center). Three reviewers viewed the images twice and the presence or absence of simulated bone defects was determined in positive and negative cases.ResultsSensitivity in different locations of FOV ranged between 0.25-1.0 and 0.75-1.0 in low and high resolutions, respectively. These values were 0.625-1.0 and 0.69-1.0, respectively for specificity. Intra-observer agreements were in the range of 0.84-1.0 and 0.75-1.0 and inter-observer agreements were in the range of 0.3-0.61 and 0.46-0.69 in high and low resolutions, respectively. The highest sensitivity was seen at the center of the FOV and with an increase in resolution from 0.3mm to 0.2mm, the sensitivity increased specially in the posterior region of the FOV while image resolutions and FOV locations did not affect specificity.ConclusionsThe highest sensitivity values were obtained at the center of the FOV and lowest values were seen in images acquired in the posterior region in low resolution. Diagnostic accuracy improved with increased resolution.Keywords: Bone, Bones, Sensitivity, Specificity, Cone, Beam Computed Tomography
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Pages 287-294ObjectivesPrecise radiographic assessment of the nasopalatine canal is required to prevent implant failure. The purpose of the current study was to determine the three dimensional (3D) morphology, as well as the dimensions of the nasopalatine canal using cone beam computed tomography (CBCT).Materials And MethodsIn this descriptive cross-sectional study, maxillary CBCT images from 300 patients (150 men, 150 women) were retrospectively evaluated. Sagittal and coronal views were reviewed to determine the nasopalatine canal morphology and dimensions. The difference in canal dimensions between men and women was evaluated using the Students t-test while the difference in canal morphology between the two sexes was assessed using Chi-square test.ResultsA total of 199 (66.3%) patients had type A canal (cylindrical without a branch), 69 (23%) had type B canal (a canal with a branch in the upper part), and 32 (10.7 %) had type C canal (a canal with a branch in the middle part). Incisive foramen diameter was 4.7±1.11mm on the sagittal section. Alveolar bone width in the anterior part of the canal was 12.3±1.7mm in the upper one third, 10.7±1.7mm in the middle one third, and 9.8±1.4mm in the lower one third. The angle of canal with palate was 109.5±5.7°. On the coronal sections, canal length was 14.1±3.0mm, incisive foramen diameter was 4.6±1.0mm, and canal diameter in the nasal floor was 5.1±1.0mm.ConclusionsSignificant differences in canal morphology were observed among the patients and CBCT was useful in determining nasopalatine canal morphology and its dimensions before implant placement.Keywords: Anatomy, Cone, Beam Computed Tomography, Dental Implants, Maxilla
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A Multidisciplinary Approach to a Seven Year-Old Patient with Incontinentia Pigmenti: A Case Report and Five-Year Follow UpPages 295-301Incontinentia pigmenti is a rare inherited disorder involving abnormalities of the skin, hair, eyes, musculoskeletal system, central nervous system, and the teeth. Dental abnormalities are the most common manifestations of this disorder. The purpose of this case report was to present the clinical and radiological findings of a seven-year-old girl as well as the results of her five-year follow up. The patient showed faded linear pigmented macular lesions on the trunk and on upper and lower limbs. Dental examination was notable for conical and peg-shaped anterior teeth as well as delayed eruption of primary and permanent teeth. In addition to conservative treatments, prosthetic treatments such as interim removable partial dentures were indicated for the patient.Keywords: Incontinentia Pigmenti, Dental Prosthesis, Genetic Diseases, Inborn