Dental Research Journal最新文献

Background: 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.

Materials and methods: 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).

Results: 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).

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

Background: Digital smile design (DSD) is a technique that utilizes the scientific methods and advanced software to design patients' smiles, presenting the visualized smile map directly to the patient. However, patients may not always find the proposed smile satisfactory or feel a sense of alignment with it. To address this concern, dentists have been integrating the tooth shape with the overall facial shape and other parameters to develop a personalized smile plan for each patient.

Materials and methods: This study employed a descriptive-analytical, cross-sectional research design conducted during the summer and fall of 2022. This research sought to evaluate patient satisfaction levels associated with three distinct DSD techniques: Visagism, Proportional, and Stepwise Comprehensive. A sample of 20 participants, evenly split between males and females, was selected, all of whom were seeking smile design treatment and did not present with skeletal, jaw, facial, or periodontal complications. Interviews were conducted to analyze personality and temperament, and smile maps were created utilizing the Visagism, Stepwise Comprehensive, and Proportional methods. Subsequently, patients evaluated the designs produced by all three methods and completed a satisfaction questionnaire. Nonparametric statistical tests, namely the Kruskal-Wallis test and post hoc Bonferroni tests, were used to examine the research hypotheses at a significance level of 0.05.

Results: The results indicated a high level of satisfaction with all three DSD methods, with no statistically significant differences observed among them. These results suggest that all three approaches effectively met the patients' expectations and preferences.

Conclusion: The outcomes of this study have practical implications for dental professionals engaged in DSD, potentially enhancing patient experiences and treatment outcomes. Further research in this domain may explore the additional factors that could influence patient satisfaction and refine the DSD process.

Background: The aim of this study was to investigate the impact of the distance between the gutta-percha and the post, as well as the type of cement used, on the incidence of microleakage in endodontically treated teeth.

Materials and methods: This experimental-laboratory study involved 72 single-canal, single-rooted teeth, which were randomly sorted into six study groups and two control groups, each containing nine teeth. The six groups were further divided based on the distance between gutta-percha and post (0 mm, 0-2 mm, and >2 mm) and then categorized by cement type into glass ionomers and resins. Microleakage was evaluated using the fluid filtration method at 15 and 30 days. Data were analyzed using SPSS software, employing between-subjects effects and post hoc Tukey tests at a 5% significance level.

Results: Cement type did not significantly affect microleakage (P = 0.598). However, microleakage increased significantly with larger gaps between the post and remaining gutta-percha (P = 0.002). No significant difference in microleakage was observed between the gapless and ≤2 mm groups (P = 0.328). Similarly, ≤2 mm and >2 mm groups did not show any notable difference (P = 0.054). However, the difference in microleakage between the gapless group and the ≥2 mm gap group was significant (P = 0.001).

Conclusion: This study found no significant difference in microleakage between glass ionomers and resin cements. Only gaps >2 mm significantly affected microleakage.

Background: This study assessed the effect of the number of short implants on stress and strain distribution in bone in the posterior mandible using finite element analysis (FEA).

Materials and methods: The study design utilized FEA, a computational technique. In FEA models, short implants (4 mm diameter and 6 mm length) were placed at the site of the mandibular first premolar to the second molar in four models: (I) two implants at the sites of teeth #4 and #7 with two pontics at the sites of teeth #5 and #6, (II) three implants at #4, #5, and #7 with one pontic at #6, (III) three implants at #4, #6, and #7 with one pontic at #5, and (IV) four implants at #4, #5, #6, and #7 with no pontic. A 100 N load was applied vertically and at a 30° angle to the occlusal surface of the crowns. Stress and strain distribution patterns in bone were evaluated using ANSYS Workbench.

Results: The highest maximum von Mises and shear stress and strain values under vertical and off-axial loadings were observed in the model with two short implants at the sites of teeth #4 and #7 with two pontics at the sites of teeth #5 and #6. In general, the highest stress and strain values were recorded following the application of off-axial loads compared to vertical loads. In all models, the highest stress was noted in the cervical part of the implants, while the maximum strain occurred in the apical part of the implants.

Conclusion: Increasing the number of short implants significantly reduces stress and strain values in peri-implant bone.

Background: This study compared the antioxidant, cytotoxic, and antibacterial effects of Citrus reticulata (C. reticulata) peel and Olea europaea (O. europaea) leaf hydroalcoholic extracts and essential oils.

Materials and methods: In this in vitro study, the antibacterial effect of the C. reticulata and O. europaea extracts and essential oils was evaluated on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) by the agar diffusion test. Their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method. Their cytotoxicity against human gingival fibroblasts was evaluated by the methyl thiazolyl tetrazolium assay in 24 and 72 h, and their antioxidant effect was assessed by the 2,2-diphenyl-1-picrylhydrazyl assay. Data were analyzed by ANOVA and Tukey's test (P < 0.05).

Results: The O. europaea hydroalcoholic extract and C. reticulata essential oils had significant antibacterial effects on A. actinomycetemcomitans. The highest and lowest growth inhibition zones belonged to C. reticulata essential oils (40.0 ± 0.0 mm) and O. europaea extract (32.3 ± 2.2 mm), respectively. The MIC and MBC were 0.78 v/v% for O. europaea extract and 6.25% for C. reticulata essential oils. Unlike the essential oils (1%, 5%, and 10% v/v), none of the extracts showed significant cytotoxicity at low concentrations (1% v/v). All essential oils and extracts, particularly O. europaea and C. reticulata extracts, had significant antioxidant effects.

Conclusion: Of the tested materials, O. europaea extract had the highest potential for possible use as an organic mouthwash due to its strong antibacterial and antioxidant effects and absence of cytotoxicity in low concentrations.

Background: Factors influencing the success of an implant placed in augmented maxillary sinus need to be recognized. The aim of this study was to investigate the effect of various oral health conditions and treatment plan details on the clinical and radiographical outcomes of implants placed in the augmented sinus.

Materials and methods: In this clinical retrospective study, 39 participants (81 implants) that received dental implants after sinus lifting between January 2005 and July 2016 were evaluated. All the participants were examined by an operator clinically and radiographically in a blinded manner. A checklist including oral health and host condition, implant and prosthesis characteristics, and surgical approach variables was completed for each participant. The effect of these variables on probing depth (PD), marginal bone loss, bone formation in sinus, and patient satisfaction was analyzed using analysis of covariance models. P <0.05 was considered statistically significant.

Results: Survival rates after surgery and restoration placement were 93% and 100%, respectively. PD was found to be significantly higher in restorations with infragingival finish lines over 1.5 mm and in implants with score "2" for gingival index. Moreover, more bone formation was observed in implants with score "0" compared with score "2" for gingival index. In addition, the participants with plaque score "0" reported significantly more satisfaction than the participants with score "2" for plaque index.

Conclusion: Inflamed gingiva was associated with more PD and less peri-implant bone formation in maxillary sinus. In addition, more patient satisfaction was reported by participants that had better plaque control.

Background: Due to a lack of manual dexterity, impaired cognitive and general development, and awareness of caregivers, special children are not able to maintain good oral health. This leads to the development of dental plaque, gingival inflammation, and further periodontal diseases. It is, thus, necessary for dentists and caregivers to understand which of oral hygiene aids can be best suited for a child with special healthcare needs. The aim of this review is to evaluate the most efficacious oral healthcare aids in children and adolescents with special healthcare needs.

Materials and methods: Systematic search was conducted in databases: PubMed, Cochrane, Google Scholar, Scopus, and ProQuest for studies published from January 1, 2000, till December 31, 2023. Randomized trials conducted among children and adolescents with special healthcare needs below 18 years using oral hygiene aids to reduce plaque were included in this review.

Results: A total of 23 articles satisfying eligibility criteria were included in the systematic review and 11 articles for meta-analysis. Meta-analysis was divided into two parts. Novel toothbrushes were more effective than manual toothbrushes with P = 0.01 (SMD: Standard Mean Difference) 95% confidence interval: -4.23 (-7.62, -0.85), I ² = 99.63%). In chemical oral hygiene aids, chlorhexidine (CHX) spray at concentration of 0.12% was found to be more effective than placebo to control plaque and was not statistically significant.

Conclusion: Current evidence suggests that novel mechanical oral hygiene aids used with CHX spray as an adjunct can be best suited for children and adolescents with special healthcare needs to control plaque.

Carcinoma ex-pleomorphic adenoma (PA) is a complex group of malignant neoplasms arising in PA. When microscopic features of the neoplastic cells are representative of carcinoma, the pathologist can easily make a definite diagnosis, but when worrisome morphology is replaced by metastatic behavior, the metastasizing PA (MPA) is a diagnostic challenge for the pathologist. Here, we present an unusual MPA to cervical lymph nodes and discuss diagnostic challenges.

Background: Oral health plays a crucial role in maintaining the general health of an individual. Parkinson disease (PD) has known to disrupt the oral functions. Prosthetic rehabilitation can be done in these patients. However, there is scarcity of literature to assess the effectiveness or impact of rehabilitation with prosthesis either fixed or removable on various oral functions and quality of life (QoL) or satisfaction of PD patients. The purpose of this systematic study was to assess the effectiveness of prosthodontic rehabilitation in patients with PD.

Materials and methods: The literature search was conducted in the PubMed and CINAHL database for the articles till 2024 in English language. An exploration of gray literature was also included through Google Scholar. Manual search in the references of the selected articles was also done for relevant articles. The methodological quality assessment of cohort studies was done using Newcastle-Ottawa quality assessment form for Cohort Studies (NOS). Assessment of cross-sectional studies was done using the Appraisal tool for Cross-Sectional Studies (tool) and aassessment of case series was done using JBI critical appraisal tool for case series.

Results: A total of 6 articles were selected from PubMed, 1 from CINAHL, and 2 from Google Scholar. Four articles studied the masticatory efficiency. Oral perception and motor ability were analyzed in two articles. Oral Health QoL was assessed in four articles. One article studied the electromyographic activity.

Conclusion: Based on this systematic review, it can be suggested that prosthetic rehabilitation using fixed or removable prosthesis offer potential benefits in PD patients improving the oral functions and QoL. However, there is a dearth of long-term research on evaluation of impact of prosthetic rehabilitation in improving the oral function and QoL of PD patients.PROSPERO Registration: CRD42024570296.

Background: The extent of surgery in cases of parotid gland pleomorphic adenoma (PA) remains challenging. This study aims to evaluate the importance of surgical margins in ensuring safe surgery for patients with PA.

Materials and methods: This prospective study was conducted to evaluate the risk of local recurrence based on surgical margins in patients with parotid PA who underwent superficial or total parotidectomy between May 2019 and November 2021 at a tertiary referral hospital in Tehran, Iran. Patients were followed for at least 2 years. Data were analyzed using SPSS version 23. The normality of data distribution was assessed using the Kolmogorov-Smirnov test. Quantitative and qualitative variables were analyzed with the independent t-test and Chi-square test, respectively. A P < 0.05 was considered statistically significant.

Results: Fifty-seven cases were included in the study. The mean age was 40.7 years, with 37 of 57 (64.9%) patients being female. Of these, 35 of 57 (61.4%) underwent superficial parotidectomy. All tumors were resected with negative margins, with an average safe margin of 0.58 cm (range: 0-3.7 cm). The greatest margin was found at the anterior side (average: 0.76 cm), whereas the smallest margin was at the vertical side (average: 0.39 cm). Postoperative radiotherapy was not administered to patients with close surgical margins. No recurrence was observed after a 2-year follow-up.

Conclusion: In the surgical resection of parotid PA, negative margins are sufficient, and there is no need to obtain additional safe margins to reduce the risk of recurrence. Therefore, extracapsular dissection (which carries higher morbidities) can be replaced by superficial parotidectomy with negative margins (which carries lower morbidities).