Frontiers in Dentistry

Relationship between Voxel Value of Cone Beam CT and Hounsfield Unit of CT: Systematic Review and Meta-Analysis

2026-02-08T08:13:19+0330

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.

Bonding to Molar-Incisor Hypomineralization Affected Teeth: A Scoping Review of Adhesive Strategies, In Vitro Performance, and Clinical Outcomes

2026-06-07T08:23:21+0430

Molar‑incisor hypomineralization (MIH) poses major restorative challenges due to compromised enamel and its reduced bonding capacity. This scoping review evaluated treatment options for MIH‑affected young permanent teeth following PRISMA‑ScR guidelines. A systematic search in PubMed, Cochrane, Science Direct and gray literature identified 21 eligible studies published between 2013 and 2025, including in‑vitro and clinical studies. Laboratory findings demonstrated lower bond strengths in MIH enamel compared with the sound enamel. Etch‑and‑rinse adhesives performed more reliably than that of self‑etch systems, while pretreatment procedures improved adhesion in some settings. Clinical studies showed resin‑based sealants and composites bonded with etch‑and‑rinse adhesives achieved higher retention. Glass ionomer and glass hybrid restorations offered mostly short-term success and are best used as an interim option. Investigated indirect restorations provided superior longevity in severe cases. Preventive adjuncts such as applying varnishes reduced hypersensitivity and caries risk. Finally, this review highlights the central role of adhesive performance in MIH management.

Accuracy of Grayscale Value in Diagnosis of Odontogenic Keratocyst and Radicular Cyst

2026-02-08T08:13:05+0330

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.

Association of Dental Status and Dry Mouth with Mental Health in Elderly Patients

2026-02-09T10:35:08+0330

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.

Morphological and Morphometric Analysis of the Incisive Foramen: A Retrospective Study on Dry Human Skulls

2026-02-08T08:16:55+0330

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.

Effect of Rinsing Water Temperature on Microleakage of Dental Composite Restorations: An In-Vitro Study

2026-05-02T11:37:05+0430

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.

Effects of 660 and 940nm Low-Level Laser Irradiation on Viability and Proliferation of Stem Cells from Human Exfoliated Deciduous Teeth

2026-05-02T11:37:09+0430

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.

Effect of Hypericum perforatum on Early Wound Healing after Tooth Extraction: A Randomized Controlled Clinical Trial

2026-05-02T11:38:59+0430

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.

Effect of Fresh Orange Juice and Industrial Orange Juice on Enamel Microhardness of Primary Teeth: An In-Vitro Study

2026-05-02T11:39:03+0430

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.

Comparison of Enamel Roughness and Calcium Release between Manual and Mechanical Stripping with and without Polishing after Demineralization

2026-05-20T08:53:43+0430

Objectives: Proximal enamel stripping is one way to create space in orthodontic treatments that leaves grooves on the enamel surface and predispose teeth to caries. The aim of this study was to compare the two common stripping systems and the effect of polishing after the stripping process on the level of surface roughness.

Materials and Methods: Twenty-five extracted teeth were randomly divided into five groups:untreated control (C), mechanical stripping (Sn), mechanical stripping and polishing (Sp), manual stripping (Dn), manual stripping and polishing (Dp). Mechanical stripping used a SWISS denta care Quality oscillating system, manual stripping used Dentaurum hand tapes, and polishing used Soflex disks. Teeth underwent pH-cycling and the amount of released calcium was measured by spectrometry. Samples were examined under atomic force microscopy (AFM) before and after demineralization. Baseline and post-demineralization surface roughness values (Ra, Rq, Rz) were calculated. Finally, scanning electron microscopy (SEM) images were obtained from two samples of each group. data analysis was done by One-way ANOVA. P-value<0.05 was considered statistically significant.

Results: There was no significant difference between the stripping methods in terms of surface roughness parameters, but there was a significant difference between the polished and unpolished groups (P<0.05). Calcium release was significantly lower in the Sp group compared to the other groups (P<0.05). In SEM images, the least amount enamel damage was related to the Sp group.

Conclusion: Unlike stripping systems, polishing is considerably useful in decreasing enamel roughness. Totally, mechanical stripping and polishing has shown the best consequences on enamel structure.

The Effect of Two Bleaching Techniques On Teeth Discolored with Different calcium silicate-based cements

2026-05-20T08:53:47+0430

Objectives: The objective of this study was to investigate tooth discoloration caused by different calcium silicate-based cements (CSCs), and assess the efficacy of two bleaching techniques in restoring the original tooth color.

Materials and Methods: In this in vitro study, 54 sound teeth were divided into three groups (n=18) of Endocem, MTA Angelus, and calcium-enriched mixture (CEM) cement. Baseline color assessments were conducted using a spectrophotometer, with subsequent color evaluation after 3 months. Each group was divided into two subgroups of internal bleaching and internal/external bleaching. The bleaching procedure was performed over a 2-week period. Two-way ANOVA was applied to investigate the interaction effect of bleaching technique and time on color change (∆E). The Tukey’s test was used as post-hoc for pairwise comparisons. P≤0.05 was considered significant.

Results: The results indicated noticeable color change in all test groups, surpassing the perceptibility threshold (ΔE>3.3). Endocem exhibited the maximum discoloration, while CEM cement displayed the minimum. Significant differences were observed between Endocem and other groups (P<0.05). Regarding the L*, a*, and b* parameters, no significant differences were found between the two subgroups except in Endocem group, where internal/external bleaching caused a significantly greater increase in color parameters compared to internal bleaching (P=0.001).

Conclusion: Endocem induced more discoloration than MTA Angelus and CEM cement. However, there was no difference in efficacy between the internal and internal/external bleaching techniques (except in Endocem), both proving effective in restoring the original color of discolored teeth.

Effect of Listerine and Sodium Fluoride Mouthwashes on Force Decay of Orthodontic Memory Elastomeric Chains: An In Vitro Study

2026-06-01T09:03:43+0430

Objectives: The interaction of mouthwashes with orthodontic elastomeric materials may alter their mechanical properties. The main purpose of this study was to evaluate the impact of 0.05% sodium fluoride Oral-B PRO-Expert Multi Protection and fluoride-free Listerine Advanced with Tartar Protection mouthwashes on the force decay behavior of memory elastomeric chains.

Materials and Methods: In this in vitro study, 90 pieces of closed gray memory elastomeric chains were randomly allocated to three distinct groups (n=30): control, sodium fluoride, and Listerine. The control samples remained fully submerged in artificial saliva over the course of the experiment. Test samples were placed daily for 1 minute in either sodium fluoride or Listerine mouthwash, then in a solution consisting of equal parts of mouthwash and artificial saliva for 30 minutes, followed by a thorough rinse with distilled water, and then placed back in the artificial saliva. Tensile tests were conducted at various time points (baseline, 1 hour, and 1, 7, and 28 days) (n=6). Data were analyzed by one-way and two-way ANOVA, and Tukey’s post-hoc test (alpha=0.05).

Results: All groups exhibited a continuous force decay over time (P<0.001). The experimental groups demonstrated significantly greater force decay compared to the control group (P<0.001). The sodium fluoride group exhibited significantly greater force decay compared to the Listerine group at all measured time points (P<0.001) except on day 28 (P=0.970).

Conclusion: Both mouthwashes accelerated the force degradation of memory elastomeric chains, with sodium fluoride causing a greater reduction except on day 28.

Early Prediction of Oral Precancerous Lesions Using Artificial Intelligence

2026-06-01T09:05:12+0430

Objectives: Oral potentially malignant disorders may present as white, red, or mixed red-white lesions and require accurate early recognition. This study evaluated whether texture-analysis features extracted from clinical digital images could distinguish oral precancerous lesions from other oral mucosal lesions and normal mucosa using gray-level co-occurrence matrix (GLCM), gray-level run-length matrix (GLRLM), and wavelet analysis.

Materials and Methods: Sixty-four clinical digital images were selected according to predefined inclusion and exclusion criteria. The dataset included leukoplakia, erythroplakia, oral submucous fibrosis, candidiasis, lichen planus, leukoderma, frictional keratosis, white spongy nevus, and normal mucosa. Regions of interest were extracted from each image, and texture features were derived using GLCM, GLRLM, and wavelet analysis. A support vector machine (SVM) classifier was then used to categorize images as oral precancerous lesions or non-precancerous/normal mucosa.

Results: GLCM yielded the highest classification accuracy (88%), followed by GLRLM (81%) and wavelet analysis (79%). The corresponding sensitivity values were 77%, 64%, and 60%, and the specificity values were 93%, 90%, and 89%, respectively. The positive predictive values were 83% for GLCM, 75% for GLRLM, and 75% for wavelet analysis.

Conclusion: GLCM-based texture features provided the best diagnostic performance in this dataset. These image-analysis methods may be useful as non-invasive adjuncts to conventional clinical examination and histopathological diagnosis; however, larger datasets and external validation are required before clinical implementation.

Vaccine Design against Fusobacterium nucleatum FadA Protein in Periodontal Infections

2026-06-07T08:23:18+0430

Objectives: A common inflammatory condition affecting oral health is periodontitis, which can lead to tooth loss if not treated early, as it destroys the supporting structures of the teeth. Fusobacterium nucleatum is an orange-pigmented bacterium commonly referred to as "the bridging species" between early and late colonizers in the oral microbiota, and it is associated with the progression of periodontal disease. This study aimed to develop an effective and precise multi-epitope vaccine against F. nucleatum, as there is currently no approved vaccine for periodontal disease.

Materials and Methods: This study employed a computational method to design a multiple epitope-based vaccine against F. nucleatum using an immunoinformatics reverse vaccinology approach. FadA, a novel adhesin unique to F. nucleatum, was a suitable peptide for vaccine development. B- and T-cell epitopes were identified and assessed to design a multi-epitope vaccine. The developed vaccine construct was analyzed for potency based on its allergenicity, antigenicity, solubility, and stability.

Results: The vaccine structure was non-allergenic and exhibited high antigenicity, stability, and solubility. This vaccine may be a candidate for eradicating F. nucleatum, based on predictions of immunogenicity responses.

Conclusion: The designed vaccine construct could generate an effective immune

A Challenging Case of Prosthetic Dental Rehabilitation by a Root-Retained Overdenture Using Intra-Radicular Attachments: A Clinical Report with a Seven-Year Follow-Up

2026-02-08T08:16:59+0330

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.

Outcome of Guided Pulpal Regeneration in Immature Molar Teeth with Chronic Apical Abscess: A Case Report and Mini-Review

2026-06-01T09:03:47+0430

This case report describes guided pulpal regeneration (GPR) of two immature permanent molar teeth with chronic apical abscess, thin dentinal walls, and open apices. Both teeth were treated with an identical protocol in two sessions, with minimum instrumentation with hand files, irrigation with 1.5% sodium hypochlorite (NaOCl), and application of 1:1 mixture of ciprofloxacin and metronidazole as an intracanal medicament, blood clot as a scaffold, and mineral trioxide aggregate (MTA) as the capping material. At the one-year follow-up, both treated teeth were asymptomatic. However, the root development procedure was different even in different roots of the same tooth, varying from only an increased thickness of dentinal walls to complete closure of the apex along with an increase in root length and dentinal wall thickness. It is concluded that the outcome of GPR is not completely predictable, and may vary among teeth with similar initial conditions and treatment approaches.