Vol 16, No 6 (2019)

Published: 2020-06-24

Original Article

  • XML | PDF | downloads: 84 | views: 131 | pages: 407-414

    Objectives: It has been reported that bulk-fill composites simplify tooth restoration with no adverse effect on the success rate. This study sought to assess the cuspal deflection of premolars with mesio-occluso-distal (MOD) cavities restored with bulk-fill and conventional posterior composite resins.
    Materials and Methods: This in-vitro experimental study was conducted on 64 human maxillary premolars. MOD cavities were prepared on teeth and restored with Filtek P60 conventional composite and Filtek Bulk Fill flowable, X-tra fill, and X-tra base bulk-fill composites in four groups (n=16). Distance between the cusp tips was measured before, five minutes, 24 hours, 48 hours, and one week after restoration. The data were analyzed using repeated-measures analysis of variance (ANOVA) and Tukey’s test (α=0.05).
    Results: The mean±standard deviation (SD) of cuspal deflection at five minutes after the restoration was 13.5±5.3, 12.2±3.5, 11.3±4.4, and 10.4±3.7 µm for Filtek P60, Filtek Bulk Fill, X-tra fill, and X-tra base, respectively. ANOVA showed that bulk-fill composites did not cause a significant reduction in cuspal deflection compared to P60 (P>0.05). Cuspal deflection in all groups significantly decreased with time (P<0.05).
    Conclusion: Bulk-fill composites have no superiority over P60 in the reduction of cuspal deflection. The cuspal deflection was variable at different time points in all groups and decreased over time.

  • XML | PDF | downloads: 29 | views: 88 | pages: 415-420

    Objectives: Hydroxyapatite (HA) nanoparticles are used to improve the physical and mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of different weight percentages of nano-HA on degree of conversion (DC) of Fuji II LC GI cement using a spectrometer.
    Materials and Methods: In this in vitro experimental study, 30 samples were fabricated of Fuji II LC (improved) GI cement in six groups (n=5) containing 0%, 1%, 2%, 5%, 7% and 10wt% nano-HA. The obtained paste in each group was subjected to Fourier-transform infrared spectroscopy (FTIR) before curing to assess the monomer to polymer DC percentage. The paste was then light-cured and underwent FTIR again. One-way ANOVA was applied to compare the DC percentage of different groups. Pairwise comparisons were performed using the Tukey’s test.
    Results: The DC was 57.88±0.57% in 0%, 60.04±0.63% in 1%, 66.92±0.54% in 2%, 65.5±0.71% in 5%, 51.49±0.24% in 7% and 50.09±0.32% in 10% nano-HA group. The difference in DC among the groups was statistically significant (P<0.0001). The highest DC was noted in 2% nano-HA and the lowest DC was found in 10% nano-HA group. Pairwise comparisons revealed significant differences between the groups in DC (P<0.0001).
    Conclusion: Increasing the weight percentage of nano-HA to 2% increased the DC but increasing the nano-HA weight percentage over 5% decreased the DC of resin-modified glass ionomer cement (RMGIC). The highest DC was noted in 5w% and 2w% nano-HA groups. Thus, 5w% and 2w% nano-HA can be used to improve the DC of RMGIC.

  • XML | PDF | downloads: 36 | views: 84 | pages: 421-428

    Objectives: Considering the importance of timesaving in pediatric dentistry, if the efficacy is achieved along with shorter working time and less technical sensitivity, the behavior management of young patients can be anticipated. This study aimed to compare the effect of precuring and postcuring of total-etch and self-etch bonding agents on the microleakage of sealants.
    Materials and Methods: This study was conducted on forty impacted third molars, which were surgically extracted. The samples were divided into five groups: 1. Control (etching and sealant), 2. Precured fifth-generation bonding agent (Adper Single Bond 2) and fissure sealant, 3. Postcured fifth-generation bonding agent (Adper Single Bond 2) and fissure sealant, 4. Precured seventh-generation bonding agent (Single Bond Universal) and fissure sealant, and 5. Postcured seventh-generation bonding agent (Single Bond Universal) and fissure sealant. All specimens were thermocycled (×1000), immersed in 0.5% basic fuchsine solution for 24 hours, sectioned, digitally photographed, and measured using the LAS EZ program. The data were analyzed using Kruskal-Wallis and Dunn’s tests.
    Results: Leakage in the control group and the third group was significantly lower than that in other groups. In pairwise comparisons, a significant difference was found between the control group and the fifth group and between the third group and the fifth group.
    Conclusion: The conventional method of sealant placement showed superior results in comparison with the use of an intermediate layer of the bonding agent.

  • XML | PDF | downloads: 34 | views: 149 | pages: 429-435

    Objectives: Cone-beam computed tomography (CBCT) is used in diagnostic situations, as well as tooth impaction and its complications. A possible sequela of tooth impaction is resorption of adjacent teeth, complicating the treatment plans. This study aimed to determine the diagnostic accuracy of high- and low-resolution CBCT scans in the detection of external root resorptions (ERRs), caused by an adjacent impacted tooth in the cementoenamel junction (CEJ), mid-root, and apical areas.
    Materials and Methods: Forty-five intact single-rooted teeth were divided into three groups of 15. Each group was dedicated to each zone of the root. Slight, moderate, and severe ERRs were formed, and CBCT scans were taken before and after the formation of ERRs. The diagnostic accuracy was assessed, and the Proportion test was used to compare the results.
    Results: The statistical analyses of high- and low-resolution images showed a significant difference (P<0.05), which implies the higher accuracy of high-resolution images. The highest diagnostic accuracy among different zones was related to the mid-root, and the lowest was related to the apical zone. In terms of the size of ERRs, the diagnostic accuracy was the lowest for slight ERRs.
    Conclusion: The most reliable and accurate diagnostic mode was found in high-resolution images, in the mid-root zone, and with severe ERRs. The lowest diagnostic accuracy was found in low-resolution images, in the apical zone, and with slight ERRs.

  • XML | PDF | downloads: 44 | views: 91 | pages: 436-449

    Objectives: The present study aimed to evaluate CD4 cell counts, lipid profile, and oral manifestations in human immunodeficiency virus (HIV)-infected and acquired immune deficiency syndrome (AIDS) patients and their correlation with seronegative controls.
    Materials and Methods: In this cross-sectional, hospital-based study, there were three groups of subjects: group A consisting of 500 healthy patients (controls), group B composed of 500 HIV-infected patients, and group C comprised of 500 AIDS patients based on their CD4 cell counts. CD4 cell counts were assessed using the CyFlow counter. Lipid profile was evaluated with the Erba EM 360 analyzer.
    Results: The results were statistically significant for CD4 cell counts (P<0.001). The levels of total cholesterol (TC) and low-density lipoproteins (LDLs) were significantly decreased while triglycerides (TGs) and very-low-density lipoproteins (VLDLs) were significantly increased in AIDS patients compared to the controls and HIV-infected patients. Various results were obtained regarding oral manifestations with different levels of significance.
    Conclusion: CD4 cell counts, TC, LDLs, TGs, and VLDLs were significantly changed in HIV-infected and AIDS patients compared to the controls.

  • XML | PDF | downloads: 63 | views: 137 | pages: 450-457

    Objectives: Toothpastes and mouthwashes contain ingredients that may be toxic for oral mucosal tissues. This study aimed to assess the cytotoxicity of the ingredients of commonly used toothpastes and mouthwashes.
    Materials and Methods: This experimental study was performed on 16 toothpastes and four mouthwashes widely available in the Iranian market. First, the concentration of six main ingredients of these products, namely sodium fluoride (NaF), sodium lauryl sulfate, cocamidopropyl betaine, zinc lactate, paraben, and sodium benzoate, was determined. The methyl thiazolyl tetrazolium (MTT) assay was used to assess the cytotoxicity of these materials for human gingival fibroblasts (HGFs). The MTT assay was performed at 1, 15, and 30 minutes following exposure to five concentrations of each material in triplicate (according to the concentrations obtained in the isolation step). Data were analyzed using three-way analysis of variance (ANOVA).
    Results: The difference in the cytotoxicity of the materials was statistically significant (P<0.001). Cytotoxicity was time- and concentration-dependent; by an increase in the concentration of the materials, their cytotoxicity increased over time. The cytotoxicity of sodium lauryl sulfate and cocamidopropyl betaine was >90%. The cytotoxicity of NaF varied from 25% to 70%, and the cytotoxicity of all concentrations of zinc lactate and sodium benzoate was <50% for HGFs.
    Conclusion: To decrease the cytotoxic effects of toothpastes, sodium lauryl sulfate and cocamidopropyl betaine should be replaced with safer detergents, and the concentration of fluoride should be decreased to 400 parts per million (ppm). Alternatively, fluoride may be replaced with other antibacterial and cariostatic agents.

  • XML | PDF | downloads: 74 | views: 106 | pages: 458-464

    Objectives: Light irradiation and heat have been used to accelerate the process of tooth bleaching. This study aimed to assess the efficacy of conventional bleaching compared to laser-bleaching using three different wavelengths of diode lasers.
    Materials and Methods: In this in-vitro experimental study, 40 extracted human central incisors were immersed in a coloring solution made of tea, coffee, and cola for 21 days. The L*, a*, and b* color parameters were measured before and after the immersion using spectrophotometry. The teeth were then randomly divided into four groups (n=10) as follows: group 1: 810-nm diode laser + Biolase Laser White 20, group 2: 940-nm diode laser + Biolase Laser White 20, group 3: 980-nm diode laser + Biolase Laser White 20, and group 4: conventional bleaching with Opalescence Boost without laser irradiation. One-way analysis of variance (ANOVA) was used to assess the effect of laser type and bleaching technique on color parameters.
    Results: The 940-nm (∆E=28.5896) and 810-nm laser groups (∆E=21.2382) showed the highest and the lowest bleaching efficacy, respectively; however, the groups were not significantly different in terms of bleaching efficacy (P>0.05).
    Conclusion: Laser-bleaching with 810-, 940- and 980-nm wavelengths of diode laser has an efficacy similar to that of conventional bleaching but in a shorter period. No difference was noted between different laser wavelengths in terms of bleaching efficacy.

  • XML | PDF | downloads: 30 | views: 87 | pages: 465-472

    Objectives: Parafunctional habits, as one of the etiological factors of temporomandibular disorders (TMD), are an individual’s response to increased stress. During stress and depression, biomarkers such as cortisol and salivary alpha-amylase (SAA) are secreted in the saliva. The present study aimed to investigate whether there is a correlation between salivary stress biomarkers and parafunctional habits.
    Materials and Methods: Thirty-two cases, from May to September 2015, were selected based on two standard stress questionnaires, namely the depression anxiety stress Scale-21 (DASS-21) and the Beck Anxiety Inventory (BAI). Saliva samples were collected to examine the level of unstimulated salivary cortisol and SAA. The significance of the results was assessed via student’s t-test and Mann-Whitney test (α=0.05).
    Results: The mean concentrations of cortisol and SAA in unstimulated saliva were significantly higher in the case group than in the control group (P=0.01 and 0.44, respectively). The mean scores of anxiety, stress, and depression were significantly higher in the case group than in the control group (P<0.05).
    Conclusion: It seems that the levels of salivary cortisol and SAA, as well as stress, anxiety, and depression scores, are higher in patients with parafunctional habits.

Case Report