Comparison between Micro-Computed Tomography and Cone-Beam Computed Tomography in the Assessment of Bone Quality and a Long-Term Volumetric Study of the Augmented Sinus Grafted with an Albumin Impregnated Allograft

Are Artificial Intelligence-Assisted Three-Dimensional Histological Reconstructions Reliable for the Assessment of Trabecular Microarchitecture?

Objectives: This study aimed to create a three-dimensional histological reconstruction through the AI-assisted classification of tissues and the alignment of serial sections. The secondary aim was to evaluate if the novel technique for histological reconstruction accurately replicated the trabecular microarchitecture of bone. This was performed by conducting micromorphometric measurements on the reconstruction and comparing the results obtained with those of microCT reconstructions. Methods: A bone biopsy sample was harvested upon re-entry following sinus floor augmentation. Following microCT scanning and histological processing, a modified version of the U-Net architecture was trained to categorize tissues on the sections. Detector-free local feature matching with transformers was used to create the histological reconstruction. The micromorphometric parameters were calculated using Bruker's CTAn software (version 1.18.8.0, Bruker, Kontich, Belgium) for both histological and microCT datasets. Results: Correlation coefficients calculated between the micromorphometric parameters measured on the microCT and histological reconstruction suggest a strong linear relationship between the two with p-values of 0.777, 0.717, 0.705, 0.666, and 0.687 for BV/TV, BS/TV, Tb.Pf Tb.Th, and Tb.Sp, respectively. Bland-Altman and mountain plots suggest good agreement between BV/TV measurements on the two reconstruction methods. Conclusions: This novel method for three-dimensional histological reconstruction provides researchers with a tool that enables the assessment of accurate trabecular microarchitecture and histological information simultaneously.

Prevalence of middle mesial root canal in mandibular molars in an Iranian population: A micro-computed tomography study

Background

Knowledge about the anatomic variations of the root canal system and their prevalence is necessary for clinicians to ideally clean the root canal system. The anatomic complexity of the root canal system is one of the reasons for its inadequate debridement, resulting in residual microorganisms and root canal treatment failure. The present study aimed to evaluate the prevalence of middle mesial root canals in mandibular molars in an Iranian population.

Materials and Methods

The samples in the present descriptive/cross-sectional study consisted of mandibular first and second molars (n = 100, with 50 first and 50 s molars). A convenient sampling method was used to collect samples. The teeth were mounted in gypsum and scanned using a micro-computed tomography unit. The images were reconstructed with software, and the relevant checklist was completed by the observers. The data were analyzed with SPSS v26 using the Chi-squared test at a significance level of P < 0.05.

Results

The prevalence of the middle mesial root canal in the present study was 36% for mandibular first molars and 22% for mandibular second molars, with an overall prevalence of 29%. The prevalence of the middle mesial root canal was not significantly different between the first and second mandibular molars (P = 0.12). The mean distance between the mesiobuccal and mesiolingual root canal orifices in the teeth with a middle mesial root canal was significantly higher than in those without the middle mesial root canal (P < 0.001). In addition, there was no significant difference in the prevalence of the middle mesial root canal between the teeth with and without the second distal root canal (P = 0.89).

Conclusion

The prevalence of the middle mesial root canal in the studied population was 29%, which is significant clinically. In addition, the mean distance between the mesiobuccal and mesiolingual root canal orifices in teeth with a middle mesial root canal was higher than that in teeth without this root canal.

Correlation between gray values in cone-beam computed tomography and histomorphometric analysis

Purpose

The aim of this study was to analyze the relationships between bone density measurements obtained using cone-beam computed tomography (CBCT) and morphometric parameters of bone determined by histomorphometric analysis.

Materials and Methods

In this in vivo study, 30 samples from the maxillary bones of 7 sheep were acquired using a trephine. The bone samples were returned to their original sites, and the sheep heads were imaged using CBCT. On the CBCT images, gray values were calculated. In the histomorphometric analysis, the total bone volume, the trabecular bone volume (referred to simply as bone volume), and the trabecular thickness were assessed.

Results

Statistical testing showed significant correlations between CBCT gray values and total bone volume (r=0.537, P=0.002), bone volume (r=0.672, P<0.001), and trabecular thickness (r=0.692, P<0.001), as determined via the histomorphometric analysis.

Conclusion

The results indicate a significant and acceptable association between CBCT gray values and bone volume, suggesting that CBCT may be used in bone densitometry.

The Use of CBCT in Evaluating the Health and Pathology of the Maxillary Sinus

The use of cone-beam computed tomography (CBCT) has been increasing in dental practice. This narrative review summarized the relevance and utilizations of CBCT to visualize anatomical structures of the maxillary sinus and common pathologies found in the maxillary sinus. The detection/visualization rate, the location and the morphometric characteristics were described. For sinus anatomy, the reviewed features included the posterior superior alveolar artery, sinus pneumatization, sinus hypoplasia, sinus septa, and primary and accessory sinus ostia. For pathology, the following items were reviewed: membrane thickening associated with periapical lesions/periodontal lesions, mucous retention cyst, and antrolith. The visualization and assessment of the maxillary sinus is very important prior to procedures that take place in close proximity with the sinus floor, such as tooth extraction, implant insertion, and sinus floor elevation. Some sinus pathologies may be associated with odontogenic lesions, such as periapical diseases and periodontal bone loss.

Criteria for the Classification of the Interradicular Septum Shape in Maxillary Molars with Clinical Importance for Prosthetic-Driven Immediate Implant Placement

The aim of this study was to use cone-beam computed tomography (CBCT) to evaluate the morphometric properties of the interradicular septum (IRS) in the maxillary molar region that may be indicative for prosthetic-driven implant placement. Following the repetitive algorithm based on the visual identification of IRS shapes, we described the following IRS shapes: arrow, boat, drop, and palatal and buccal convergence. The incidence of IRS shapes showed significant differences for the first and second maxillary molars (the highest frequency for the arrow shape, and the lowest for the drop shape) with no significant difference between the molars. The most prominent width indicative for implant placement was observed in the palatal convergence shape, whereas the height criteria were the most satisfying in the buccal convergence-shaped IRS for both molars. Apart from the parameters in the coronal view, the image analysis in the axial view revealed that IRS surface area, required for the implant placement, was the most prominent in the palatal convergence shape for the first, and boat shape for the second molars. Our results showed the benefits of CBCT diagnostics in posterior maxilla morphometric analysis. IRS shape classification may be helpful in achieving more rapid and accurate planning for interventions in this region.

Micro-computed tomography in preventive and restorative dental research: A review

Purpose

The use of micro-computed tomography (micro-CT) scans in biomedical and dental research is growing rapidly. This study aimed to explore the scientific literature on approaches and applications of micro-CT in restorative dentistry.

Materials and Methods

An electronic search of publications from January 2009 to March 2021 was conducted using ScienceDirect, PubMed, and Google Scholar. The search included only English-language articles. Therefore, only studies that addressed recent advances and the potential uses of micro-CT in restorative and preventive dentistry were selected.

Results

Micro-CT is a tool that enables 3-dimensional imaging on a small scale with very high resolution. In this method, there is no need for sample preparation or slicing. Therefore, it is possible to examine the internal structure of tissue and the internal adaptation of materials to surfaces without destroying them. Due to these advantages, micro-CT has been recommended as a standard imaging tool in dental research for many applications such as tissue engineering, endodontics, restorative dentistry, and research on the mineral density of hard tissues and bone growth. However, the high costs of micro-CT, the time necessary for scanning and reconstruction, computer expertise requirements, and the enormous volume of information are drawbacks.

Conclusion

The potential of micro-CT as an emerging, accurate, non-destructive approach is clear, and the valuable research findings reported in the literature provide an impetus for researchers to perform future studies focusing on employing this method in dental research.

A Comparative Study on the Voxel Values in Alveolar Bones Acquired by MDCT and Newly Developed Dental Dual-Energy CBCT

The purpose of this study was to analyze the effectiveness of newly developed dental dual-energy (DE) cone-beam computed tomography (CBCT) to compare both the voxel values in hard bone tissue of DE-CBCT and multidetector computed tomography (MDCT) images, collected in a clinical trial conducted at Seoul National University Dental Hospital. A software implemented as a scripted module of a three-dimensional (3D) slicer was developed to register the volume data from the MDCT space to DE-CBCT, locate the same 3D regions of interest (ROIs) in each image space, and extract the statistics of the ROIs. The mean values were paired and used as representative values of the ROIs. A scatter plot with the line of equality and Bland–Altman (BA) plot of difference for a pair of measured means were used for statistical analysis. Of the ROI pairs, 96% were within ±15% from the identity line, and more than 95% of the measured ROI pairs were within the limits of agreement of the 95% confidence intervals (CIs), with the CI of the limits in BA plots. The newly developed dental DE-CBCT showed a level of voxel value accuracy similar to that of MDCT.

Influence of Anatomical Parameters on the Dimensions of the Subantral Space and Sinus Mucosa Thickening after Sinus Floor Elevation. A Retrospective Cone Beam Computed Tomography Study

BACKGROUND

Various anatomical parameters might influence the surgical approach for maxillary sinus floor elevation. The objective of the present study was to retrospectively evaluate the influence of anatomical parameters on the dimensions of the subantral space and of the sinus mucosa thickening after sinus floor elevation.

MATERIAL AND METHODS

Seventy-eight maxillary sinuses in sixty-five patients were evaluated on cone beam computed tomographies taken before surgery and after one week (t1w) and nine months (t9m). Several parameters such as the distance XF between an axis parallel to the base of the nose (X-axes) and the sinus floor (F) were correlated with the height gain (IF) at t1w and t9m and the post-surgical edema.

RESULTS

A weak significant positive correlation was observed between height gain vs. sinus height of interest (XF), the balcony, and the sinus floor angle. The post-surgical edema was influenced by the initial mucosa thickness and the xenograft used.

CONCLUSIONS

Various parameters might affect height gain and sinus mucosa thickening after sinus floor elevation. The height of interest, the balcony, and the sinus floor angle showed significant correlations with height gain. The initial thickness of the mucosa and the biomaterial used influenced the post-surgical edema.

Evaluation of the Histomorphometric and Micromorphometric Performance of a Serum Albumin-Coated Bone Allograft Combined with A-PRF for Early and Conventional Healing Protocols after Maxillary Sinus Augmentation: A Randomized Clinical Trial

The aim of this study was to compare the microarchitecture of augmented bone following maxillary sinus augmentation (MSA) after healing periods of 3 (test) and 6 (control) months using the combination of advanced platelet-rich fibrin (A-PRF) and a serum albumin-coated bone allograft (SACBA). Twenty-six patients with 30 surgical sites who required two-stage MSA were enrolled and grafted with the combination of A-PRF and SACBAs. The surgical sites were randomly allocated to the test or control group. During implant site preparation, 17 bone core biopsy samples were collected from each study group for histological, histomorphometric and micromorphometric analysis. Resonance frequency analysis was performed at the time of implant placement and 6, 8, 10, and 12 weeks postoperatively. The percentage of newly formed bone was 44.89 ± 9.49% in the test group and 39.75 ± 8.15% in the control group (p = 0.100). The results of the µCT analysis showed no significant differences in morphometric parameters between the study groups. The implant stability quotient was not significantly different between the two groups at 10 and 12 weeks postoperatively. Based on these findings, the total treatment time may be reduced by 3 months with the use of A-PRF and SACBAs for two-stage MSA.

Evaluation of Quality of Life and Satisfaction in Patients with Fixed Prostheses on Zygomatic Implants Compared with the All-on-Four Concept: A Prospective Randomized Clinical Study

Purpose: No published research has compared patients’ quality of life and satisfaction with fixed prostheses supported by zygomatic implants with those supported by all-on-four prostheses. The aim of this study was to evaluate patients’ quality of life and satisfaction with fixed prostheses on zygomatic implants compared with the all-on-four concept. Materials and Methods: A total of 80 patients with atrophic edentulous maxillae were randomized into two groups: Group 1 (rehabilitated with fixed prostheses supported by 2–4 zygomatic and 2–4 conventional implants in the anterior region) and Group 2 (fixed prostheses on four implants in the anterior region following an all-on-four concept). One year after placement of the definitive prostheses, patients completed OHIP-14 and satisfaction questionnaires. Results: In all seven domains of the OHIP-14 and in the overall scores, a worse quality of life was found in Group 2 patients, with statistically significant differences between the two groups (p ≤ 0.05). Patients with zygomatic implants were more satisfied with their prostheses, with a statistically significant difference (p < 0.001). Conclusions: According to the results of this study, rehabilitation of patients with edentulous atrophic maxillae with prostheses supported by zygomatic implants combined with anterior implants provided better patient quality of life and satisfaction than prostheses supported by four implants.

Quantitative analysis of metal artefacts of dental implant in CBCT image by correlation analysis to micro-CT: A microstructural study

OBJECTIVES

Quantification of dental implant metal artefacts in CBCT images using correlation analysis of trabecular microstructural parameters from CBCT and micro-CT, and analysis of the effect of varying the angular position of the subject.

METHODS

Polyurethane synthetic bone blocks were first scanned without implants by micro-CT and CBCT. Two dental implants were then placed parallel in the bone blocks and these specimens were scanned by CBCT with different alpha angles. Three volumes of interest (VOI) were set for further analysis. Six microstructural parameters were measured: trabecular thickness (Tb_Th), trabecular spacing (Th_Sp), bone volume per total volume (BV/TV), bone surface per total volume (BS/TV), connectivity density (CD) andfractal dimension (FD). Micro-CT measurements were used as a gold standard for CBCT. Spearman correlation coefficients for each microstructural parameter from CBCT and micro-CT were calculated and compared using Steiger's Z test.

RESULTS

Without the implants, in VOI₁, the Spearman correlation coefficients of Tb_Th, Tb_Sp, BV/TV, BS/TV, CD and FD were 0.599, 0.76, 0.552, 0.566, 0.664 and 0.607, respectively. With the implants, the correlation coefficients decreased sharply in VOI₁. As the alpha angle increased from zero to 90°, the correlation coefficients increased and became significant. Similar results appeared in VOI₂. In contrast, in VOI₃, the correlation coefficient decreased as the alpha angle increased.

CONCLUSIONS

Metal artefacts were successfully quantified using microstructural parameters in terms of the image quality of the CBCT. Changes in alpha angle affected the quality of the CBCT image.

The Influence of Surgical Experience and Bone Density on the Accuracy of Static Computer-Assisted Implant Surgery in Edentulous Jaws Using a Mucosa-Supported Surgical Template with a Half-Guided Implant Placement Protocol-A Randomized Clinical Study

The aim of our randomized clinical study was to analyze the influence of surgical experience and bone density on the accuracy of static computer-assisted implant surgery (CAIS) in edentulous jaws using a mucosa-supported surgical template with a half-guided implant placement protocol. Altogether, 40 dental implants were placed in the edentulous jaws of 13 patients (novice surgeons: 18 implants, 6 patients (4 male), age 71 ± 10.1 years; experienced surgeons: 22 implants, 7 patients (4 male), age 69.2 ± 4.55 years). Angular deviation, coronal and apical global deviation and grey level measurements were calculated for all implants by a blinded investigator using coDiagnostiX software. 3DSlicer software was applied to calculate the bone volume fraction (BV/TV) for each site of implant placement. There were no statistically significant differences between the two study groups in either of the primary outcome variables. There was a statistically significant negative correlation between angular deviation and both grey level measurements (R-value: −0.331, p < 0.05) and BV/TV (R-value: −0.377, p < 0.05). The results of the study suggest that surgical experience did not influence the accuracy of implant placement. The higher the bone density at the sites of implant placement, the higher the accuracy of static CAIS.