Dental Research Journal最新文献

Background: In dentistry, esthetic restorations are vital. Adequate polishing can minimize color changes of a tooth. The aim of this study was to evaluate the effect of the Prophy-Mate neo device, which uses airflow, on surface roughness and color changes in enamel.

Materials and methods: In this in-vitro study included 30 teeth immersed in tea solution for 7 days. The specimens were divided into three groups based on the polishing procedure (airflow with calcium carbonate, airflow with sodium bicarbonate, and diamond paste). The whitening procedure was performed according to the instructions for each powder of airflow (Prophy-Mate neo, NSK, Japan) and paste. After polishing, the specimens were again immersed in a tea solution for another 7 days. Color assessment was carried out at baseline (T1) and after polishing (T2) using the CIELab* system. In addition, the morphology of the enamel surface for each specimen from each group was evaluated by profilometer at T1 and T2, and the paired t-test and Tukey's were used to compare results between groups.

Results: The variation in surface roughness (Ra) between calcium carbonate (0.381 μm) and sodium bicarbonate (0.447 μm) powders was not significant, but the performance of diamond paste was significantly better. The difference between the secondary staining after polishing was lower than the pigment absorption in the primary staining (before polishing) in the diamond paste group.

Conclusion: Overall, the study did not show any significant reduction in the amount of surface roughness and color changes in airflow compared to traditional polishing methods. The cost and services of the Prophy-Mate neo device make it challenging to introduce airflow as an alternative to conventional techniques (P<0.05).

Background: Minimizing apical debris extrusion may help reduce postoperative pain, flare-ups and enhance the patient's comfort. This study aimed to compare the apical debris extrusion weights of two rotary file systems, Denco Gold and Denco Blue, with those of hand files.

Materials and methods: In this in vitro study, 69 mandibular first molars with a curvature < 10° and two separate root canals and foramen in the mesial root were selected. The samples were randomly divided into three groups: Denco Blue rotary file, Denco Gold rotary file, and hand files. After instrumentation, the extruded apical debris was gathered in glass containers and dehumidified. The weight of the debris was measured and compared. Data analysis was conducted using SPSS 22 with one-way analysis of variance and Tukey tests.

Results: The highest mean (standard deviation) of debris extrusion weight was observed with hand files at 0.21 (0.03), followed by the Denco Gold rotary file at 0.10 (0.31), and the lowest with the Denco Blue rotary file at 0.08 (0.27). There was a significant difference (P < 0.001) between the rotary files and hand files, but no significant difference among the rotary files (P > 0.159).

Conclusion: Both Denco Blue and Denco Gold rotary files resulted in less apical debris extrusion compared to hand files, with the two rotary file systems showing similar levels of debris extrusion.

Background: Current challenges in bone grafting revolve around the limited availability of autografts and the complications associated with their use. Promising alternatives include osteoinductive substances stimulating stem cells to mature into bone-forming osteoblasts. However, existing products lack optimal characteristics of a bone graft. The study aimed to evaluate the impact of L-arginine treatment on hydroxyapatite (HA) derived from ovine bone and compare its surface and mechanical properties to that of the commercially available xenograft-Bio-Oss.

Materials and methods: The research was structured as an in vitro investigation, wherein HA was formulated from ovine bone. The sintering process involved heating it to 360°C for 3 h and adding the amino acid L-arginine. Different tests were done which included scanning electron microscopy (SEM), X-ray diffractometry, Fourier-transform infrared spectroscopy (FTIR), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The goal was to compare these results with a commercially available bone graft called BioOss, especially regarding their physical and chemical characteristics. Data were analyzed in SPSS software using one way ANOVA test, significant level at 0.05.

Results: A bone graft made of HA and L-arginine displayed a complex and interconnected pore structure, indicating that the sintering process had a significant impact. SEM confirmed this. FTIR analysis identified peaks at 650-700 cm^-1 and 1000-1100 cm^-1, confirming the presence of HA and L-arginine. X-ray Diffraction assessments also confirmed the existence of both substances in the sintered specimens, supporting their suitability for various biomedical applications.

Conclusion: The study presents a novel approach, deproteinizing a bone graft followed by sintering at 360°C with L-arginine. Physicochemical analyses confirmed desired mechanical attributes and surface characteristics. Further investigations are needed to evaluate cellular adherence, immunological response, and osteogenesis in relevant animal models.

Background: Intraoral scanners (IOS) have been developed to address the drawbacks of traditional impression systems, such as improving patient comfort and expediting the restoration process. The objective of this study was to compare the dimensional accuracy of IOSs with traditional impression systems.

Materials and methods: In this experimental study, a maxillary reference model was utilized for the study. The mesiodistal, occlusogingival, and buccolingual distances between points were measured on the model using a digital caliper and recorded as the control group. The reference model was then scanned once using an IOS device (CEREC AC) to generate a digital model. Reference points were measured and recorded using EXOCAD V.2019 software. Sixteen alginate impressions were cast in separate trays from the reference model, and dental stone IV was poured into them. Reference points were also measured on the casts using a caliper. Finally, the measurements of IOS models, alginate templates, and reference models were compared in terms of size and dimensional differences. Data analysis was performed using the analysis of variance with independent t-tests, with a significance level of <0.05. The study utilized a maxillary reference model.

Results: The mean differences in mesiodistal dimensions of only the right second premolars (P = 0.017), buccolingual dimensions of central incisors (P = 0.037), lateral incisors (P = 0.050), and right first molar (P = 0.028) showed significant differences between IOS and alginate methods compared to the reference model. The dimensions reported in the IOS method were higher (0.71-1.26 mm) than those in the alginate method compared to the reference model.

Conclusion: Based on the results of this study and acknowledging its limitations, it can be concluded that the IOS method yielded a greater number of measurements than the reference model when evaluated on a limited number of teeth within the complete maxillary arch. However, the measurements obtained using the alginate method were more closely aligned with those of the reference model. The minimal differences observed between digital impressions and traditional measurement techniques, the IOS method may be regarded as a viable alternative to conventional methods, owing to its numerous advantages.

Background: Coronal discoloration is a common complication when using calcium silicate-based cements in esthetic zones. An ideal endodontic cement should provide favorable esthetic results alongside optimal biological and mechanical properties. This study aims to evaluate the discoloration of three calcium silicate-based cements-Cold Ceramic, Ortho MTA, and Retro MTA-in the presence of blood and normal saline.

Materials and methods: In this experimental study, 48 human anterior teeth were prepared and randomly divided into six groups (n = 8) based on the type of cement (Cold Ceramic, OrthoMTA, RetroMTA) and environment (blood or normal saline). Color analysis of tooth crowns was performed using a spectrophotometer before applying the cements and at 30 and 60 days after application. Repeated measures analysis of variance was used to evaluate the effects of blood, material type, and time on discoloration (ΔE). As the data showed a non-normal distribution, the Kruskal-Wallis test was used for intergroup comparisons, and the Wilcoxon test was applied for intragroup analyses over time (P-value < 0.05).

Results: After one month, specimens exposed to blood exhibited greater discoloration than those exposed to normal saline. All groups showed noticeable discoloration at two months, with blood exposure exacerbating the effect. Across different times and environments, OrthoMTA caused more discoloration than the other materials. However, the differences were not significant. (P-value > 0.05).

Conclusion: IIn all three groups, blood-exposed and normal saline environments caused clinically noticeable discoloration over time. These materials are, therefore, not recommended for use in esthetic zones.

Background: It is suggested to use a customized abutment confirming to the configuration of the new extraction socket. Since there are no systematic reviews regarding this issue, the aim of this systematic review was to assess the efficacy of customized healing abutments versus titanium healing abutments on peri-implant tissue healing in fresh socket implants to improve the treatment prognosis in the clinic.

Materials and methods: Electronic searches were conducted on PubMed/MEDLINE, Embase, Cochrane, and Google Scholar databases by the end of June 2022. All randomized controlled studies, prospective, retrospective, human studies of preimplant tissue healing around customized or titanium healing abutments, follow-up studies of more than 6 months, and in English were included in this study. The exclusion criteria were studies that were not clinical, with a follow-up period of <6 months, and those that assessed abutment healing.

Results: Forty-six studies were obtained following database research. Based on the eligibility criteria, five studies were finally included. Qualitative data analysis showed that two studies reported that customized abutments caused a significant decrease in a buccolingual width while two others did not report accurate results. Furthermore, one study only pointed to the significance of this change within 1 month after implant placement. Consequently, customized healing abutments may cause higher volume changes in the presence of thin bone phenotypes and facilitate the closure of large sockets. In addition, these investigations reported the same implant survival rate during the follow-up period for both methods.

Conclusion: Customized healing abutments exhibit efficacy in sealing immediate implant sockets, particularly in cases with thin bone phenotypes. These abutments induce significant volume changes, aiding in the closure of larger sockets and thereby preserving the socket volume.

Background: Recent studies have indicated that assessing the expression levels of cancer stem cell markers is critical in predicting the behavior of these neoplasms. This study aimed to evaluate and compare the expression levels of CD44 and epithelial cell adhesion molecule (EpCAM) markers in pleomorphic adenoma (PA) and mucoepidermoid carcinoma (MEC) using immunohistochemistry.

Materials and methods: In this cross-sectional descriptive-analytical study, 20 samples each of PA and MEC were selected from Kashani Hospital, Isfahan, Iran, based on inclusion and exclusion criteria. Specimens were prepared using immunohistochemical methods and analyzed under an optical microscope. Pathologists evaluated microscopic grade, staining intensity and percentage, and the staining intensity distribution (SID) index. Statistical analysis was conducted with SPSS (version 26), employing the Kolmogorov-Smirnov test, t-test, Chi-square, and Fisher's exact test.

Results: The mean frequency of stained cells for both CD44 (P = 0.39) and EpCAM (P = 0.40) markers showed no statistically significant differences between the PA and MEC groups. Similarly, the mean intensity of staining did not differ significantly for either CD44 (P = 0.40) or EpCAM (P = 0.18). The average SID index for the EpCAM marker in the MEC group was significantly higher than the PA group (P = 0.03) and for the EpCAM marker, there was a significant difference between the average SID index and all three variables of microscopic grade (P = 0.01), clinical stage (P = 0.00), and 3-year prognosis (P = 0.02).

Conclusion: The use of EpCAM immunohistochemical marker may help to predict the behavior of salivary gland tumors and obtain better treatment measures for patients.

Background: Any deficiency or problem in the shear bond strength between restoration and tooth surface can lead to recurrent decay, gingival issues, and associated esthetic concerns. Cement acts as a material to bond restorations to the tooth surface, filling the void space between the tooth and the restoration to establish this bond. This study aims to investigate the bonding strength of two common types of cement - polycarboxylate and zinc phosphate - with Sintron alloy (chromium-cobalt) in dental restorations.

Materials and methods: This research is conducted in vitro on 24 Sintron alloy discs cemented with two types of polycarboxylate (Poly-F, Dentsply, US) and zinc phosphate cement (Harvard Cement, Germany) on 24 extracted maxillary central incisors. Teeth were sandblasted with 50-micrometer aluminum oxide (Al₂O₃) particles. Disc-shaped alloy specimens with specific dimensions were prepared. The specimens were then bonded to the teeth surface using each cement and were subjected to shear bond strength testing using a Universal Testing Machine (Instron, 3367, Canton, MA, USA). An independent sample t-test was performed with P value significance of lower than 0.05.

Results: The t-test with P = 0.150 showed no significant difference between the zinc phosphate and polycarboxylate cement groups.

Conclusion: The study found no statistically significant difference in the bond strength of Sintron alloy when using zinc phosphate and polycarboxylate cement. Therefore, it can be concluded that the bond strength is similar for both cements.

Background: The aim of the present study was to evaluate the clinical and radiological effectiveness of transcrestal sinus elevation and simultaneous implant placement using osseodensification (OD) and crestal approach sinus (CAS) instruments.

Materials and methods: This randomized controlled double-blinded clinical trial included 20 participants with edentulous spaces requiring 20 implants having residual bone height >5 mm in the posterior maxilla. Participants were randomly allocated into the CAS group and OD group. Indirect sinus elevation with simultaneous implant placement was performed in both groups. Implant stability (IS) was evaluated at baseline and 3 months. Crestal bone loss (CBL) was measured at 3, 6, and 12 months. Apical bone gain (ABG) was measured at 6 and 12 months. Surgical time and patient comfort using the Visual Analog Scale were assessed during the surgery. Unpaired t-test, ANOVA, and Friedman tests were used for inter- and intragroup comparisons. P ≤ 0.05 was deemed statistically significant.

Results: Sinus elevation and simultaneous implant placement showed good clinical and radiological outcomes in both groups. Intergroup comparison showed a significantly greater primary and secondary IS (P = 0.005, 0.008) in the OD group. CBL was less in the OD group (P = 0.02 and 0.03 on mesial and distal sides) than in the CAS group at 6 months of evaluation. ABG was higher in the OD group (4.164 ± 0.293) than the CAS group (2.819 ± 0.415). The average surgical time taken was greater (87.00 ± 15.49 min) in the CAS group than in the OD group (69.00 ± 20.24 min).

Conclusion: Both CAS and OD groups showed significant improvement in all parameters. OD group showed greater benefits in terms of enhanced primary stability, less CBL, enhanced ABG, and lesser surgical time compared to the CAS group.

Background: Dental caries are caused by acidic by-products from bacterial fermentation of dietary carbohydrates and can lead to oral complications. Oral candidiasis is another disease affecting quality of life, especially in diabetic and immunocompromised patients. Interest in using Persian medicine to manage oral diseases has been growing recently. Persian medicine texts highlight medicinal plants such as Artemisia dracunculus, Citrus medica, and Pimpinella anisum for oral health benefits. The present research explores the antimicrobial effects of these plants against microorganisms causing caries and oral candidiasis.

Materials and methods: This is an in vitro study, aimed to evaluate the chemical composition, and antimicrobial effects of C. medica, P. anisum, and A. dracunculus on oral pathogens. Based on criteria such as accessibility, recognizability, and novelty, leaves of A. dracunculus, peels of C. medica, and seeds of P. anisum were chosen. Their chemical compositions were analyzed after procuring the plant samples and preparing their essential oils (EOs). Subsequently, the diameters of the inhibition zones and their minimum inhibitory concentration (MIC) and minimum bactericidal concentration/minimum fungicidal concentration values were measured.

Results: The major chemical components of P. anisum's EO (PAEO), A. dracunculus' EO (ADEO), and C. medica's EO (CMEO) were estragole (75.77%), anethole (89.03%), and limonene (92.31%), respectively. All pathogens were susceptible to all EOs except Streptococcus salivarius, which was resistant to CMEO and had the highest MIC. Except for this EO, all the other EOs showed inhibition zones with diameters ranging from 6 to 30 mm, ADEO being the most effective. In MICs, Lactobacillus acidophilus was the most sensitive microorganism tested with MIC. In contrast, the most resistant microorganism was S. salivarius.

Conclusion: The attained results demonstrated that the examined plants possess notable antimicrobial properties against oral pathogens.