Dental Research Journal
Volume:22 Issue: 4, Apr 2025

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.

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.

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

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. 

The use of 3D printers in dentistry is expected to increase in the future. However, there is limited information available on the accuracy of dental 3D printers for creating dental and implant models. This study aimed to compare the accuracy of 3D‑printed casts and traditional plaster casts for the fabrication of tooth‑supported and implant‑supported restorations.

This in vitro study involved a dental model with implant analogs placed at the sites of the right first premolar and molar for an implant‑supported bridge and the left first premolar and molar that received preparation for a tooth‑supported bridge. Addition silicone impressions were made and poured with dental stone to create 10 plaster casts. The model was scanned using an intraoral scanner, and 20 casts were 3D‑printed using digital light processing (DLP) and liquid crystal display (LCD) printers (10 casts for each method). All 30 casts, including the reference model, were scanned using a laboratory scanner, and the obtained Standard Triangle Language files were superimposed in Geomagic software. Data analysis revealed violations of normality and homogeneity of variances. As a result, the Kruskal–Wallis H test, a nonparametric method, was employed to compare root mean square (1 RMS = 100 μm) values across three groups. All statistical analyses were performed using SPSS version 27. RMS values were calculated (P < 0.05).

The RMS value was significantly lower in the conventional plaster cast group compared to the LCD group (P = 0.002). However, there was no significant difference between the LCD and DLP groups (P = 0.214) or between the conventional and DLP groups (P = 0.345). The interdental distance in the conventional group was significantly lower than that in the 3D‑printed groups (P < 0.05), but there was no significant difference between the two printing methods (P = 0.31). The interimplant distance was lower in the 3D‑printed groups compared to the conventional group, and this difference was significant between the DLP and conventional groups (P = 0.02).

Although plaster casts demonstrated higher accuracy, 3D‑printed casts using additive technology yielded accurate results within the clinically acceptable range (<200 µm).

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.

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.

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.

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

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.

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.

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).

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

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.

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.

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).

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.