Frontiers in Dentistry

This systematic review aims to investigate the relationship between voxel value obtained from Cone Beam Computed Tomography (CBCT) in studies compared to Hounsfield of Multidetector Computed Tomography (MDCT) in homogeneous and heterogeneous samples. A literature search was carried out in the databases PubMed, Scopus, Embase, and Web of Science searching for relevant literature until February 2022 (updated at July 2023). A risk of bias assessment of the studies was performed using a modified checklist based on the Cochrane Collaboration’s tool and the Journal of Biomedical Informatics. The software version 20.104 of MedCalc was used to conduct the meta-analysis of correlation coefficients. Out of 4750 articles in the initial search, 13 met the eligibility criteria. Out of the articles, eight studies were included in the meta-analysis. Both heterogeneous and homogenous samples showed a strong correlation between the voxel value of CBCT and Hounsfield Unit (HU), with high heterogeneity (r=0.900 and 0.998 respectively and I2>70%). Two other meta-analyses were conducted for kVp and voxel size, which showed a high correlation. The 95% confidence interval was used to present the estimated pooled correlation. The strong correlation of voxel value and HU indicates the possible potential of CBCT in radiographic bone density measurement. However, further research is needed to obtain an accurate conversion equation for translating voxel values of CBCT to HU. Calibration of voxel values within each scan using a reference object and consideration of both linear and non-linear regression could improve accuracy.

Objectives: Radicular cyst (RC) and odontogenic keratocyst (OKC) are among the most commonly identified cysts in both the maxilla and mandible. With the advancements in 3D imaging techniques such as cone-beam computed tomography (CBCT), there is an opportunity to thoroughly examine the boundaries of these lesions and quantify the grayscale of CBCT images, known as the grayscale value (GSV). This study investigated the reliability of CBCT GSV in distinguishing between RC and OKC.

Materials and Methods: A total of 60 specimens with confirmed pathological diagnoses of RC and OKC were meticulously selected. Before surgical biopsy of each lesion, CBCT images were obtained and analyzed using Romexis version 2.9.2 software to compute the mean GSV of each lesion. Statistical analysis was then conducted using SPSS version 1.0.0.1406, and a linear, backward regression model was used to analyze the differences in GSV between lesion categories (alpha=0.05).

Results: Upon extracting the mean GSV of the selected sections of each type of lesion, no statistically significant difference was observed between the mean GSVs of the two lesion categories (P>0.05).

Conclusion: The present findings regarding lack of a significant difference in the mean GSV between RC and OKC were substantial, and suggest that the GSV may not be a reliable index for differentiating these cystic lesions from each other, a conclusion that could potentially impact future diagnostic practices.

Objectives: Psychological disorders are prevalent medical conditions that can negatively affect oral health. Due to the increase in the elderly population, and higher risk of psychological conditions in this age group, this study assessed the association of mental health evaluated by the 28-Item General Health Questionnaire (GHQ-28) and oral health in the elderly patients.

Materials and Methods: Overall, 150 elderly patients aged 60 years and higher presenting to the dental clinic of School of Dentistry, Tehran University of Medical Sciences in 2019 participated in this cross-sectional study. Oral and dental examinations were conducted to assess the dental caries status using the decayed, missing, and filled teeth (DMFT) index, number of existing teeth, and self-reported dry mouth. Sociodemographic status, oral hygiene behaviors, and medical history of the participants were also recorded. The GHQ-28 was used to assess their mental health. Data were analyzed by SPSS version 25 using the correlation tests (alpha=0.05).

Results: Of all the participants, 64 (42.7%) were females, and the age range was 60 to 90 years (mean age: 67.56±6.42 years). The mean total GHQ score was 4±3.8. The DMFT score and number of teeth had significant associations with severe depression and social dysfunction (P<0.05). Dry mouth was directly associated with the total GHQ score and anxiety (P<0.05).

Conclusion: Elderly people with severe depression suffered from poor oral health. Comprehensive oral and dental examination and paying close attention to mental health aspects should be considered in regular dental check-ups and oral health promotion programs for the elderly.

Objectives: This study aimed to examine the morphological and morphometric characteristics of the incisive foramen and incisive canal in dry human skulls.

Materials and Methods: The sample consisted of 150 dry adult skulls, with no distinction regarding sex or ethnicity. The analysis included the number of incisive canals within the foramen, their dimensions (area and diameter), and their anatomical connections with the incisive fossa and the nasal cavity.

Results: All incisive canals were found to communicate with the nasal cavity. The most frequently observed configuration was foramina containing two or more canals.

Conclusion: Precise anatomical knowledge about the incisive canal and its foramen is essential for clinical procedures involving the anterior maxilla. Morphological variations in this region may affect surgical access, technique selection, and procedural outcomes.

Objectives: This study assessed the impact of rinsing water temperature on microleakage of dental composite restorations.

Materials and Methods: This in vitro study was conducted on 72 extracted premolars. Buccal and lingual Class V cavities were prepared with gingival margins 1mm beneath the cementoenamel junction (CEJ) and occlusal margins 2mm above the CEJ. The specimens were classified into three groups (n=24) for rinsing with water at 23°C, 4°C, and 45°C before the bonding procedure. Lingual cavities were bonded with a self-etch adhesive, and buccal cavities were bonded with a total-etch adhesive. After composite restoration, the specimens underwent 1000 thermal cycles between 5-55°C. They were then divided into two groups for storage for either 24 hours or 2 months. Optical and electron microscopic assessments were performed to score microleakage at the occlusal and gingival margins of the specimens. The Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests were run to analyze the data (alpha=0.05).

Results: Regardless of the bonding system and storage time, microleakage was significantly higher in the 4°C rinsing water group (P<0.05). Gingival margins bonded with the total-etch adhesive had a significantly higher microleakage than the occlusal margins in both 23°C and 45°C groups (P<0.05), but the self-etch adhesive showed no significant difference (P>0.05).

Conclusion: According to the results of this in vitro study, rinsing the cavity with warm water (23°C and 45°C) appears to be an effective method to reduce the rate of microleakage.

Objectives: This study evaluated the effects of 660 and 940nm lasers on viability and proliferation of stem cells from human exfoliated deciduous teeth (SHED).

Materials and Methods: SHED were cultured and divided into six groups for laser irradiation: 660nm laser at 25mW with energy densities of 1 and 2J/cm² for 8 and 16 seconds, and 940nm laser at 100mW with the same energy densities and durations. Two additional groups served as controls with no laser exposure. Cell viability was evaluated by the methyl thiazolyl tetrazolium (MTT) assay, and cell proliferation was measured by cell counting with a Neubauer chamber and qualitatively evaluated by 4′,6-diamidino-2-phenylindole (DAPI) staining at 24 and 72 hours post- irradiation. Data were analyzed using one-way ANOVA, followed by Tamhane’s and Tukey’s tests.

Results: Irradiation with 940nm laser enhanced cell proliferation compared to both 660nm laser and control groups at 24 and 72 hours (P<0.05), as confirmed by DAPI staining. At 24 hours, all laser-treated groups showed increased cell viability relative to the control, although the increase in the 660nm/2J/cm² group was not statistically significant (P>0.05). At 72 hours, only 940nm laser group showed significantly higher cell viability and proliferation than the control group (P<0.05).

Conclusion: These findings suggest low-level laser therapy, particularly at the wavelength of 940nm enhances the viability and proliferation of stem cell, supporting its potential as a promising tool in regenerative medicine and tissue engineering.

Objectives: Hypericum perforatum (H. perforatum) has natural anti-inflammatory properties when used as a dressing on ulcers and burn wounds. The aim of this study was to investigate the effect of topical application of hydroethanolic gel of H. perforatum on soft tissue healing in tooth extraction sockets.

Materials and Methods: This split-mouth randomized controlled clinical trial was performed on 30 patients aged 18-30 years who required simultaneous extraction of maxillary premolars bilaterally for orthodontic reasons. After tooth extraction, 2mL of 3% H. perforatum gel was injected into the extraction socket in the intervention side. Pain was measured based on a Numeric Rating Scale (NRS). Socket healing was assessed using the standardized Landry, Turnbull, and Howley index. Repeated measures ANOVA and generalized estimating equations (GEE) were employed to compare different indices between the two groups (alpha=0.05).

Results: The mean age of the participants was 23.53 years. Of all, 25 were females and 5 were males. The intervention side had a significantly lower pain than the control side (P<0.05). The wound size decreased at 3 and 7 days, and it was smaller in the intervention side than the control side (P<0.05). The healing index score was significantly higher in the intervention side than the control side (P<0.001).

Conclusion: The results showed that 3% H. perforatum hydroethanolic gel was effective for promoting soft tissue healing in tooth extraction sockets, decreasing pain, and improving the wound healing index.

Objectives: Increased consumption of non-alcoholic carbonated soft drinks, diet sodas, and fruit juices greatly contributes to dental erosion. This study aimed to compare the microhardness of primary tooth enamel before and after exposure to fresh and industrial (commercial) orange juices.

Materials and Methods: In this in vitro experimental study, 30 enamel blocks were obtained from primary teeth, and randomly divided into three groups (n=10). The pH levels of fresh and commercial orange juices were measured. The enamel blocks were immersed in fresh and industrial orange juices for 10 minutes, 4 times a day, over a period of 15 days. Specimens in the third group were stored in artificial saliva to serve as the control group. Enamel microhardness was assessed using the Vickers hardness test both before and after immersion in orange juices. Data were analyzed using paired t-test and ANOVA (alpha=0.05).

Results: There was a significant decrease in enamel microhardness in both the fresh and commercial orange juice groups (P<0.001), with no significant difference in this regard between the two orange juice groups (P=0.209).

Conclusion: The microhardness of primary enamel can decrease following exposure to both fresh and commercial orange juices, but no significant difference was found between the two types regarding the enamel microhardness reduction.

Conventional complete dentures cause underlying bone resorption over time, which leads to retention loss and poor adaptation of denture. These complications can be prevented in use of root-supported or tooth-supported overdentures. A tooth-retained overdenture with intra-radicular attachments is recommended in case of insufficient inter-arch space to improve denture retention, stability, function, and support. This study describes a tooth-supported overdenture to gain retention from the canine teeth, and compensate for the limitation in inter-occlusal space. This clinical report helps dental clinicians in selection of the appropriate attachment type in different conditions, and designing a suitable treatment plan. After 7 years of follow-up, no complication was observed.