Frontiers in Dentistry最新文献

Objectives: This study evaluated the effect of ozone water disinfection on dimensional stability and accuracy of silicone impression materials. Materials and Methods: According to ISO-4823, a stainless-steel die was fabricated for this in vitro study. Three horizontal parallel lines, namely x, y, and z (25, 50, and 75µm in width and 25mm in length) running perpendicular to two vertical lines, namely D1 and D2 (0.075±0.008mm wide), were created on the superior surface of the die. Group A served as the control group with no disinfection. Disinfection was performed with 2% glutaraldehyde in group B, 5.25% sodium hypochlorite in group C, and ozone water in group D for 10 minutes. Totally, 60 samples were fabricated. The silicone impression samples were allowed to polymerize in a thermostatically controlled water bath at 35±1ºC for 10 minutes. The dimensional stability and accuracy of the silicone impression samples were evaluated by using a video measuring microscope and an optical microscope. Data were analyzed by two-way ANOVA followed by post-hoc analysis with the Scheffe test (alpha=0.05). Results: The highest dimensional stability (25.01mm) and accuracy (25.02µm) were seen in addition silicone putty and light body impression with ozone water disinfection, and the lowest parameters were seen in condensation silicon putty and light body disinfected with 2% glutaraldehyde (24.87mm and 24.88 µm, respectively); this difference was statistically significant (P<0.001). Conclusion: Ozone water disinfection caused minimal changes in dimensional stability and accuracy when compared to 2% glutaraldehyde and 5.25% sodium hypochlorite disinfection.

Rhabdomyosarcoma is a rare soft tissue malignant neoplasm with striated muscle differentiation often found in the head and neck region. In our case a 33-year-old man presented with a bulging mass near his right mandibular second molar tooth, identified as a unilocular destructive lesion on an X-ray. An incisional biopsy confirmed rhabdomyosarcoma, leading to a hemi-mandibulectomy. Histopathologic findings showed spindle and rhabdoid cells with positive immunoreactivity to Desmin, myogenin and myoD1. In conclusion, it is crucial to differentiate rhabdomyosarcoma from other more common intraosseous malignancies, and using Desmin staining as part of the initial immunohistochemical panel can aid in the diagnosis process.

Objectives: Despite the recent advances in orthodontic appliances, color change of elastomeric ligatures over time remains a problem causing patient dissatisfaction. This study aimed to assess the color stability of different types of orthodontic elastomeric ligatures in the oral environment. Materials and Methods: This clinical trial was conducted on 67 patients. After applying the exclusion criteria, 11 participants were excluded, and 56 remained. Four different brands of elastomeric ligatures namely Ortho Technology, Ortho Organizers, American Orthodontics, and SIA were randomly used in the four quadrants of each patient (n=14 from each brand). Discoloration of ligatures was scored in the oral cavity by orthodontists and patients on the day of placement (T0) and 28 days later (T1). Photography and CIE L*a*b* color space were used to assess the color change (∆E). Data were analyzed by the Kruskal-Wallis and Bonferroni tests. Results: All brands showed discoloration. The highest ∆E was identified in SIA and Ortho Technology, while the lowest was recorded in Ortho Organizers. The lowest ∆b (yellowness) and the greatest reduction in L* (lightness) and ∆a (redness) were observed in Ortho Organizers. According to the opinion of patients and orthodontists at T0 and T1, SIA was the least visible followed by Ortho Technology. No significant difference was found between orthodontists and patients at T0 and T1 regarding the visibility of ligatures (P>0.05). Conclusion: After 28 days, all brands of elastomeric ligatures showed considerable discoloration. Ortho Organizers showed the highest color stability.

Objectives: The purpose of this study was to investigate the effect of laser etching, air bone particle abrasion and acid etching on shear bond strength between re-cast Nickel Chromium alloy and dental ceramics. Materials and Methods: A master die was made according to ISO 9693; TR (11406). A total of 40 samples were fabricated with 50%w nickel-chromium alloy and 50%w previously casted nickel-chromium alloy. The samples were divided into four groups based on the surface treatment applied. Group 1 served as the untreated control, Group 2 underwent etching with 10% hydrochloric acid (HCl), Group 3 received surface treatment via air-borne particle abrasion, while Group 4 was conditioned using a pulsed Nd:YAG laser. Shear bond strength between ceramic and metal was tested using a universal testing machine and the mode of debonding was evaluated using scanning electron microscope. The obtained values were statistically analyzed using one-way ANOVA and Tukey's HSD Post Hoc test. Results: The mean values of shear bond strength for Group 1 was 22.69±2.63Mpa, Group 2 was 27.05±2.15Mpa, Group 3 was 34.46±2.46Mpa and Group 4 was 39.54±2.16Mpa. The difference among the groups was significant (P<0.001). Hence there was a statistical difference seen in shear bond strength between control and acid etching, air borne particle abrasion and laser etching. Conclusion: Laser surface conditioning produced more surface roughness compared to acid etching and air bone particle abrasion on re-cast Nickel Chromium alloy which increased the shear bond strength markedly between recast nickel-chromium alloy and dental Ceramic.

Objectives: Pentraxin-3 (PTX3) and interleukin-6 (IL-6) are two of the most important inflammatory cytokines produced by cells in periodontal tissues. The present study aims to evaluate the levels of PTX3 and IL-6 in serum and gingival crevicular fluid (GCF) in patients with generalized periodontitis stages II and III, grades A and B, and periodontal health individuals before and after scaling and root planing (SRP). Materials and Methods: In this study, 22 patients with periodontitis (12 males and 10 females) and 22 periodontal health controls (11 males and 11 females) were selected. All patients underwent full-mouth SRP. Serum and GCF samples were collected before and one month after SRP. PTX3 and IL-6 levels in serum and GCF samples were evaluated by enzyme-linked immunosorbent assay. Data analysis was performed using Mann-Whitney U and Wilcoxon tests (P<0.05). Results: Serum levels of PTX3 were significantly higher in the periodontitis group than the controls (P<0.05). GCF PTX3 levels and serum and GCF IL-6 levels were not significantly different between the groups. Furthermore, this study did not show any significant changes in the levels of these cytokines before and after SRP. Conclusion: Among the studied cytokines and media, only serum PTX3 levels showed a significant difference between periodontitis patients and healthy controls and could serve as a diagnostic marker of periodontal inflammation. SRP did not affect the levels of these cytokines, suggesting that other inflammatory factors may be involved in disease process. However, additional longitudinal prospective studies are needed to confirm these results.

Objectives: The current study aimed to develop a valid and reliable questionnaire in both English and Persian to assess dental patients' knowledge and attitude during the COVID-19 outbreak. Materials and Methods: Through a comprehensive literature review, we designed the primary questionnaire in English and then translated it into Persian. The questionnaire consisted of six sections covering background information, knowledge of emergency dental treatments, transmission routes of disease, required preparation, source of information, and attitude. To evaluate the validity of the questionnaire, the researchers obtained expert opinions using the Item Content Validity Index (I-CVI) and Scale Content Validity Index (S-CVI/Ave). They distributed online versions of the questionnaire to a total of 60 English-speaking adults in Nigeria and the United States, and 60 Persian-speaking adults in Iran to measure its reliability using Cronbach's alpha. Results: I-CVI score, S-CVI/Ave, and Cronbach's alpha of the questionnaire ranged from 0.29-1, 0.62-0.99, and 41.1-87.6%, respectively. After reviewing the scores and comments received on each item, taking into account the opinions of the research team, a decision was made to remove, merge, modify, or retain certain items. This led to a final version of the questionnaire consisting of nine questions in the background section and 46 items in the remaining five sections. Conclusion: Overall, the developed questionnaire appears to be valid and reliable for assessing the knowledge and attitude of dental patients toward COVID-19 in dental settings. It can potentially serve as an appropriate scale in future infectious disease epidemics across diverse populations.

Objectives: Preserving the original canal morphology is the ideal goal during root canal preparation. This study aimed to compare canal transportation at various cross-sections using the Neoniti and Wave One Gold rotary systems, both applied with reciprocal motion. Materials and Methods: Forty acrylic S-shape canal simulator endo-blocks were used in this study. Two preparation protocols were applied: (1) Proglider (#16/0.02) followed by Wave One Gold (#20/0.07) and (2) GPS followed by A1#20 (reciprocal motion). The canals were dyed before and after preparation, and images were captured from both stages using blocks. These images were then superimposed using Adobe Photoshop to assess differences, and measurements were taken with Digimizer image analysis software. The data was analyzed using an independent samples T-test, with statistical significance set at P<0.05. Results: Transportation was significantly greater in the middle third of the canal simulator in the group that was treated with Proglider (#16/0.02) followed by Wave One Gold (#20/0.07). However, no significant differences were observed in the coronal or apical thirds. Conclusion: While the manufacturer of Neoniti recommends using this system with continuous rotational motion, it can also be effectively utilized with reciprocal motion, yielding satisfactory results while respecting the canal anatomy.

Objectives: This study aimed to investigate the aesthetic aspect of screw-retained restorations by examining three different types of filling materials used for the access cavity, highlighting the significance of aesthetics in implant restorations. Materials and Methods: In this laboratory investigation, simulation samples of screw-retained restorations were filled with flowable composite resin (group F), opaque and flowable composite resin (group O) and porcelain plug (group P) at baseline (T0). The samples were subjected to thermocycling twice (T1 and T3), undergoing 1000 cycles in coffee, orange juice, and distilled water, followed by washing performed after each thermocycling (T2 and T4). Colorimetric analysis and surface roughness measurements were conducted, and the data were statistically analyzed using. two-way analysis of variance (ANOVA), ,Tukey post hoc, two-way analysis of covariance (ANCOVA), and paired-t test. P<0.05 was considered significant. Results: The type of filling material had a significant effect on the color difference observed between the restoration and filling materials (P<0.05). Notably, samples from group P exhibited a more pronounced color difference at T4, despite showing a lower color difference at T0, when compared to group O. Conclusion: The use of porcelain plugs did not provide a notable advantage over the combination of flowable and opaque composite resins, particularly given the difficulties in fabricating and positioning porcelain plugs within the access cavity. Therefore, it is recommended to utilize flowable composite resins in conjunction with an opaque composite resin layer beneath, to effectively conceal any dark shades from the underlying metal.

Objectives: This study aimed to compare the antifungal efficacy of Ganoderma lucidum (G. lucidum) and clotrimazole for treatment of denture stomatitis (DS). Materials and Methods: This double-blind randomized clinical trial was conducted on 50 patients with DS types I and II assigned to two groups (N=25). In the first group, G. lucidum extract was administered in the form of 5% gel while 1% clotrimazole gel was prescribed for the second group. Pain intensity according to the visual analog scale (VAS), and the percentage of DS recovery based on the Budtz-Jorgenson index were evaluated and recorded after 7 and 14 days. Data were analyzed using the Chi-square test, independent samples t-test, repeated measures ANOVA, and logistic regression (alpha=0.05). Results: The percentage of complete recovery on day 7 in the G. lucidum group (28%) was higher than that in the clotrimazole group (16%) but not significantly (P=0.592). Not wearing dentures overnight significantly increased the odds of recovery by 6.56 times, while the odds of recovery decreased by 0.03 times in DS type II, as compared to DS type I (P= 0.009). Conclusion: No significant difference existed between the antifungal efficacy of G. lucidum and clotrimazole for clinical treatment of DS. Thus, Ganoderma may be regarded as an alternative treatment, especially in patients' resistant to azoles. Nonetheless, further clinical studies are required to shed more light on this topic.

Objectives: Dental clinics are one of the major producers of mercury-containing waste due to the use of dental amalgam.  The atmospheric transport and persistence of mercury and its compounds in the environment, coupled with their high potential for bioaccumulation and detrimental effects on human health and ecosystems, underscore the necessity for effective management of mercury waste. Due to the lack of comprehensive and integrated guidelines for the effective management of dental amalgam waste in Iran, the objective of this study was to adapt a guideline for the management of amalgam waste in dental settings within the country. Materials and Methods: The method used was based on the adaptation principles presented by the Ministry of Health and Medical Education, and included searching and reviewing guidelines related to the management of amalgam waste in developed countries, extracting recommendations, revising the recommendations considering the local infra-structures and conditions, and receiving expert opinions and reaching consensus according to the RAND/UCLA Appropriateness Method. Results: The final guideline includes 34 recommendations in 5 areas: manage-ment of the amalgam scraps, considerations for dental equipment, management of the extracted teeth containing amalgam restorations, management of the amalgam capsules, and considerations for placement and replacement of the amalgam restorations. Conclusion: The use of this guideline in medical universities, public and private dental clinics, along with the supervisory role of the Ministry of Health and Medical Education, can be a way to minimize the environmental hazards of mercury.