Use of fractal analysis in dental images for osteoporosis detection: a systematic review and meta-analysis

Evaluation of mandibular bone structure changes in patients with phenylketonuria through fractal analysis and radiomorphometric indices

OBJECTIVES

The aim of this study was to evaluate the effect of phenylketonuria (PKU) on mandibular bone structure by comparing the bone of PKU patients with healthy controls using fractal analysis (FA) and the radiomorphometric indices of mandibular cortical width (MCW) and mandibular cortical index (MCI).

STUDY DESIGN

In total, 32 patients with PKU were analyzed and compared with the control participants. Regions of interest in panoramic radiographs were selected and the fractal dimension (FD) obtained from FA was calculated. MCW was defined as the cortical thickness of the inferior border of the mandible at the level of the mental foramen. MCI classified the endosteal edge of the mandibular cortex as C1: straight and sharp, C2: the presence lacunar resorption spaces, and C3: distinctly porous and severely eroded. The significance level was P < .05.

RESULTS

All FD and MCW values were significantly lower in the PKU patients. The prevalence of C1 was significantly lower and prevalence of C2 was significantly higher in the PKU group.

CONCLUSIONS

The differences in FD and radiomorphometric indices between patients with PKU and healthy controls may indicate a potential impact of PKU on mandibular bone structure.

Characterization of a Novel Col1a1G643S/+ Osteogenesis Imperfecta Mouse Model with Insights into Skeletal Phenotype, Fragility, and Therapeutic Evaluations

Osteogenesis imperfecta (OI) is an inheritable skeletal disorder characterized by bone fragility often caused by pathogenic variants in the COL1A1 gene. Current OI mouse models with a glycine substitution in Col1a1 exhibit excessive severity, thereby limiting long-term pathophysiological analysis and drug effect assessments. To address this limitation, we constructed a novel OI mouse model mimicking a patient with OI type III. This was achieved by introducing a G-to-A transversion at nucleotide position 2428 in the Col1a1 gene via CRISPR-Cas9 technology in C57BL/6 J mice. The resulting heterozygous variant mice (Col1a1G643S/+) displayed reduced body weight and pronounced skeletal abnormalities. Micro-CT analysis at 12 weeks revealed decreased vertebral bone parameters and altered cortical bone characteristics, indicative of bone fragility. Additionally, the abnormalities of the anisotropy, complexity, connectivity, and structure of trabecular bone were revealed. A three-point bending test confirmed the fragility, with reduced displacement and fracture energy in both sexes. Furthermore, we evaluated the effect of 4-phenylbutyric acid on the bone in Col1a1G643S/+ mice at 12 weeks, observing no significant effects, likely due to the absence of collagen retention in the ER in this model. Despite being a moderate OI model, Col1a1G643S/+ mice manifest a distinct and fragile bone phenotype, making them suitable for extended studies. This model offers a valuable platform for investigating long-term pathophysiological aspects of OI and assessing the efficacy of potential therapeutic interventions.

Fractal analysis and assessment of lacunarity in mandibular osteoradionecrosis: a cross-sectional study with control group

The objective of this study was to evaluate the fractal dimension (FD) and lacunarity of the mandibular bone, comparing patients with and without osteoradionecrosis (ORN). In a cross-sectional study with a control group, 25 patients were included and divided into a case group (with ORN, n = 14) and a control group (without ORN, n = 11). A digital panoramic radiograph taken after the end of radiotherapy (RT) was evaluated for each patient. FD and lacunarity of the mandibular bone were determined using ImageJ software. Descriptive, bivariate, and ROC curve analyses were performed. Cohen's d effect sizes were calculated. Significance was established at p < 0.05. The mean FD and lacunarity values were not significantly different between the groups. The area under the curve for FD and lacunarity were 0.579 and 0.661, respectively. The cut-off point for FD was ≤1.1714 and for lacunarity, > 0.3821, correctly classifying the majority of cases and controls. Most participants in the case group (63.6%) had a FD ≤ 1.1714 and the majority of participants in the control group (63.6%) had a FD >1.1714 (p = 0.395). For lacunarity, most individuals in the case group (72.7%) had a value > 0.3821 and most participants in the control group (63.6%) had a value ≤ 0.3821 (p = 0.198). In conclusion, the FD and lacunarity values did not show statistically significant differences between patients with and without ORN. However, the moderate and large magnitude of the effects seem to indicate that the results may be clinically relevant.

Palatal rugae change shape following orthodontic treatment: a comparison between extraction and non-extraction borderline cases using fractal analysis and 3D superimposition

INTRODUCTION

Palatal rugae are used as anatomical landmarks on the hard palate, in various clinical applications; in forensics, for insertion of mini-screws, and for superimposition. There is ambiguous evidence on whether they change during orthodontic treatment and to what extent. Therefore, we investigated changes in the shape, complexity, and area occupied by palatal rugae following orthodontic treatment with and without extractions.

MATERIALS AND METHODS

Pre- and post-treatment plaster models of maxillae of 28 cases involving first premolar extractions (17 females and 11 males) and 33 non-extraction cases (19 females and 14 males) were scanned and analysed. All participants were selected from a parent sample via discriminant analysis and represent borderline cases. We applied mesh cropping, ball pivoting, distance mapping, contour cropping of rugae, best-fit superimposition, fractal dimension (FD) analysis, and creation of rugae's convex hull area with Viewbox 4 software. The average distance between the closest points of the outlines of pre- and post-treatment palatal rugae (indicating shape change in the set of rugae), disparity in their pre- and post-treatment FDs (reflecting the complexity of their shapes), area occupied by rugae, arch depth, and size of palatal surface were then computed.

RESULTS

The medians of the average distance between pre- and post-treatment outlines after best-fit superimposition were 0.39 mm (interquartile range [IQR]: 0.34-0.51) and 0.27 mm (IQR: 0.22-0.34) mm for the extraction and non-extraction groups, respectively (P < 0.001). The median pre-treatment FDs were 1.497 (IQR: 1.481-1.521) for the extraction group and 1.481 (IQR: 1.456-1.509) for the non-extraction group, whereas their median post-treatment FDs were 1.502 (IQR: 1.472-1.532) and 1.489 (IQR: 1.469-1.501), respectively. The differences between pre- and post-treatment fractal dimensions were not found to be significant, neither within each group, nor across the groups. On the other hand, the surface area occupied by rugae showed a median increase of 14.7 mm2 (IQR: 0.0-46.5) (P = 0.003) following non-extraction treatment only.

CONCLUSION

Palatal rugae change shape during orthodontic treatment, but their shape complexity, as measured by fractal dimensions, remains unaltered. Extraction treatment exerts a more pronounced effect in shape change compared to treatment without extractions. Nevertheless, non-extraction orthodontic treatment increases the surface on which rugae lie, as measured by means of the convex hull. Although the alterations may appear minor, it is necessary to exercise caution and prudence when employing rugae for superimposition and forensic dentistry purposes.

Photobiomodulation With Infrared and Dual-Wavelength Laser Induces Similar Repair and Control of Inflammation After Third Molar Extraction: A Double-Blinded Split-Mouth Randomized Controlled Trial

BACKGROUND

Photobiomodulation therapy (PBMT) has been showed to have beneficial effects on the healing and control of inflammation associated with oral surgical wounds. However, different PBMT protocols have been proposed and it is not clear if different protocols impact the hard and soft tissues healing equally.

PURPOSE

To compare the tissue repair of postextraction alveoli of third molars between treated with dual-wavelength PBMT (red and infrared) or PBMT with infrared laser (IRL) alone.

STUDY DESIGN, SETTING, SAMPLE

This split mouth randomized controlled trial enrolled 20 patients, who were submitted to the extraction of the 4 partially erupted or fully impacted third molars between August 2023 and December 2023 at the clinic of the INPES postgraduate school (Institute for Clinical Health Research), and at the Federal University of Uberlândia. Adult with all the 4 molars were included in this study, while patients with systemic diseases/conditions, with less than 4 third molars were excluded of this study.

EXPOSURE VARIABLE

The exposure variable is PBMT treatment. Treatment side was randomly allocated to according to the PBMT protocol applied on the postextraction sockets: IRL-PBMT: irradiation with PBMT with an IRL (808 nm) and IRL-RL-PBMT: irradiation with dual-wavelength PBMT (660 and 808 nm).

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was the bone tissue healing that was measured using the fractal analysis and bone tissue density assessed using the radiographic images. The secondary outcome variable was soft tissue healing measured assessing the facial dimensions variations and a healing index that assessed the tissue consistence, color, exudation, bleeding, and edema. Additionally, the analyses centered on the patients' perceptions was assessed by the application of a visual analogic scale to assess pain, bleeding, edema, difficulty in chewing, and mouth opening conditions. Subjects were clinically evaluated at 3, 7, 14, 30, and 90 days after the surgical procedure.

COVARIATES

The covariates are the tooth position, and the demographic data (age and sex).

ANALYSES

The evaluation of the effects of the independent variables (Treatment and period of evaluation) on the primary and secondary outcomes was performed through the application of the repeated measures ANOVA (P < .05).

RESULTS

The sample was composed of 20 subjects with a mean age of 28.58 ± 8.94 years, and 12 (60%) were females. There were no statistically significant differences between the 2 treatments for any outcome variables (P > .10).

CONCLUSION AND RELEVANCE

It can be concluded that PBMT with dual wavelengths (red and infrared) and an IRL alone induced similar postoperative clinical results after third molar extraction surgeries.

How does the direction of region of interest selection affect the fractal dimension?

OBJECTIVES

Introduction Fractal analysis (FA) is a computational method used to quantify the complex trabecular structure of bone. While FA has been widely applied in dentistry, there are challenges in standardizing the technique due to factors such as image resolution, region of interest (ROI) selection, and image processing. This study aimed to investigate the impact of the direction of ROI selection (DROIS) on fractal dimension (FD) calculations.

METHODS

Panoramic radiographs of 226 individuals aged 20-35 years were analyzed. ROIs were selected on the mandibular condyle, angular region, and mental region, and oriented at 0°, 22.5°, 45°, and 67.5° angles. FD was calculated using the box-counting method in ImageJ. The Friedman test and Wilcoxon signed-rank test were used for statistical analysis.

RESULTS

The FD values differed significantly between the angled ROI groups in all three regions (Friedman test, p < 0.0001). Pairwise comparisons showed significant differences in FD between most ROI orientations, except between 22.5° and 67.5° in the angular region.

CONCLUSIONS

DROIS is an important factor that should be considered in FA studies to ensure reliable and reproducible FD values. Appropriate methodological choices can help account for the influence of DROIS on FD calculations..

The relationship between radiomorphometric indices and fractal dimension analysis: a cone-beam computed tomography study

The purpose of this study is to evaluate the relationship between radiomorphometric indices and fractal dimension (FD) analysis in jawbone radiographic density using Cone-Beam Computed Tomography (CBCT). The study included 87 CBCT datasets from dental patients aged 50-79. Four radiomorphometric indices (Computed Tomography Cortical Index (CTCI), Computed Tomography Mental Index (CTMI), Computed Tomography Index-Superior (CTI-S), and Computed Tomography Index-Inferior (CTI-I)) along with age, gender, remaining teeth, and mandibular bone height were evaluated. FD was assessed in trabecular bone near the mental foramen (ROI 1) and on the mandibular cortical bone (ROI 2). Relationships between indices and variables were analyzed using Pearson chi-square, Fisher's exact, one-way ANOVA, Kruskal-Wallis, and Spearman's rho tests. ANOVA showed significant differences in mandibular bone height (p = .004) and FD at ROI 2 (p = .000) across three mandibular cortex types (C1, C2, C3). Spearman's rho indicated significant correlations between FD at ROI 2 and CTMI, CTI-S, CTI-I (p = .000), and between mandibular bone height and CTMI (p = .010). The correlations of FD at ROI 2 ranged from strongest to weakest with CTCI, CTMI, CTI-S, and CTI-I. High-risk osteoporosis radiomorphometric indices are associated with FD analysis of cortical bone.

Comparison of quantitative radiomorphometric predictors of healthy and MRONJ-affected bone using panoramic radiography and cone-beam CT

OBJECTIVES

To determine the most distinctive quantitative radiomorphometric parameter(s) for the detection of MRONJ-affected bone changes in panoramic radiography (PR) and cone-beam CT (CBCT).

METHODS

PR and sagittal CBCT slices of 24 MRONJ patients and 22 healthy controls were used for the measurements of mandibular cortical thickness (MCT), fractal dimension (FD), lacunarity, mean gray value (MGV), bone area fraction (BA/TA), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N). MCT was measured in the mental foramen region. While FD and lacunarity were measured on mandibular trabecular and cortical regions-of-interest (ROIs), the remaining parameters were measured on trabecular ROIs. The independent samples t-test was used to compare the measurements between the MRONJ and control groups for both imaging modalities (P = .05).

RESULTS

MCT was the only parameter that differentiated MRONJ-affected bone in both PR and CBCT (P < .05). None of the remaining parameters revealed any difference for MRONJ-affected bone in CBCT (P > .05). FD, lacunarity, MGV, BA/TA, and Tb.Sp could distinguish MRONJ-affected trabecular bone in PR (P < .05). The correspondent ROI for both imaging methods that was reliable for detecting MRONJ-affected bone was the trabecular bone distal to the mental foramen above the inferior alveolar canal (ROI-3).

CONCLUSIONS

MCT is a reliable parameter for the discrimination of MRONJ-affected bone in both PR and CBCT images. PR may be used to detect MRONJ-affected trabecular bone using FD, lacunarity, MGV, BA/TA, and Tb.Sp measurements as well.

Efficacy of the CALM® Algorithm in Reducing Motion-Induced Artifacts in CBCT Imaging: A Fractal Dimension Analysis of Trabecular Bone

OBJECTIVE

The primary goal of this investigation was to ascertain the efficacy of the CALM® motion artifact reduction algorithm in diminishing motion-induced blurriness in Cone Beam Computed Tomography [CBCT] images. The assessment was conducted through Fractal Dimension [FD] analysis of the trabecular bone.

METHODS AND MATERIALS

A desiccated human mandible was subjected to Planmeca ProMax 3D® scanning under eight distinct protocols, marked by variations in motion presence [at 5, 10, and 15 degrees] and the deployment of CALM®. In every scan, five distinct regions of interest [ROIs] were designated for FD analysis, meticulously avoiding tooth roots or cortical bone. The FD was computed employing the box-counting method with Image-J 1.53 software.

RESULTS

Our findings reveal that a 5-degree motion does not significantly disrupt FD analysis, while a 10-degree motion and beyond exhibit statistical differences and volatility among the sites and groups. A decreased FD value, signifying a less intricate or "rough" bone structure, correlated with amplified motion blurriness. The utilization of CALM® software seemed to counteract this effect in some instances, reconciling FD values to those akin to the control groups. Nonetheless, CALM®'s efficacy differed across sites and motion degrees. Interestingly, at one site, CALM® application in the absence of motion resulted in FD values considerably higher than all other groups.

CONCLUSION

The study indicates that motion, particularly at 10 degrees or more, can considerably impact the FD analysis of trabecular bone in CBCT images. In some situations, the CALM® motion artifact reduction algorithm can alleviate this impact, though its effectiveness fluctuates depending on the site and degree of motion. This underscores the necessity of factoring in motion and the employment of artifact reduction algorithms during the interpretation of FD analysis outcomes in CBCT imaging. More research is necessary to refine the application of such algorithms and to comprehend their influence on different sites under varying motion degrees.

The Utility of Radiomorphometric Mandibular Indices on Cone Beam Computer Tomography in the Assessment of Bone Mass in Postmenopausal Women: A Cross-Sectional Study

BACKGROUND

The present study examined the potential use of computed tomography radiomorphometric mandibular indices on cone beam CT (CBCT) for the assessment of bone density in postmenopausal women with low bone mass.

METHODS

We included 104 postmenopausal women who received dual-energy X-ray absorptiometry (DXA) using a DXA scanner and mental foramen (MF) region CBCT using a NewTom VGi EVO Cone Beam 3D system. We assessed the relationships between the following DXA parameters: lumbar, femoral neck, and total hip T-scores, bone mineral density (BMD), lumbar trabecular bone score (TBS), and mandibular inferior cortical bone thickness at 4 sites. The cross-sectional images were obtained, as follows: anterior (A)-10 mm anterior from the MF; molar (M)-10 mm posterior from the MF; posterior (P)-25 mm posterior from the MF; symphysis (S)-equidistant from the centers of the right and left MF.

RESULTS

We found that A and M indices showed statistically significant moderate positive correlations with lumbar spine, femoral neck, and total hip BMD, as well as TBS. The P index demonstrated moderate positive correlations with these measurements, while the S index did not show significant correlations with BMD or TBS in postmenopausal women.

CONCLUSIONS

These findings support the potential usefulness of CBCT-derived radiomorphometric mandibular indices for non-invasive bone health assessment in clinical practice.

Effect of Fixed and Removable Functional Therapy on Mandibular Anterior Bone Structures: A Fractal Analysis Study

(1) Background and aim: The effects of functional therapies on dentoalveolar and skeletal structures have been investigated in orthodontics for many years. The aim of this retrospective study was to evaluate the changes caused by fixed and removable functional therapy in the mandibular anterior trabecular structures using fractal dimension (FD) analysis. (2) Methods: A total of 60 patients with skeletal and dental class II malocclusion were included in the study and three groups were formed: the untreated control group (CG), the Forsus fatigue-resistant device group (FFRDG), and the Monoblock group (MBG). Bone areas of interest determined in the buccoapical of the mandibular incisors and the symphysis in the lateral cephalometric radiographs taken before (T0) and after (T1) functional therapy were evaluated using FD analysis. The relationship between the FD and IMPA (Incisor Mandibular Plane Angle) angles was evaluated. Parametric and nonparametric tests were used in statistical analysis according to normality distribution. The statistical significance level was determined as p < 0.05. (3) Results: There was no statistically significant difference between the FD values of all groups at T0 (p > 0.05). At T1, buccoapical FD values were significantly lower in FFRDG and MBG compared to the control group (p < 0.05), while symphyseal FD values were not found to be significant (p > 0.05). The IMPA angle was significantly lower in the FFRDG and MBG than in the control group at T0, while it was higher at T1 (p < 0.05). While a significant negative correlation was observed between the IMPA angle and buccoapical FD values in both FFRDG and MBG (p < 0.05), it was not observed with the symphysis FD values (p > 0.05). (4) Conclusions: Trabecular changes caused by functional therapy in the mandibular anterior bone can be evaluated on lateral cephalometric radiographs with FD analysis. It was concluded that orthodontists should ensure controlled changes in the IMPA angle during functional therapy, especially for the decreases in FDs seen in the buccoapical alveolar region due to the forward movement of the mandibular incisors.

Pilot study of fractal dimension analysis of osteogenesis for bone substitute materials of Bio-Oss in lateral sinus augmentation

BACKGROUND

Fractal dimension (FD) analysis has been proposed and validated in osseointegration-related research. The aim of this study was to evaluate the feasibility of FD analysis in the osteogenesis detection of bone substitute materials (BSMs) of Bio-Oss in maxillary lateral sinus augmentation.

METHODS

Patients who received lateral maxillary sinus augmentation and underwent grafting with BSMs (Bio-Oss) were included in the study. The cross sections of the BSMs under cone-beam computed tomography (CBCT) at mesial, distal, and sagittal directions were obtained immediately after the graft (T0) and 6 months later (T1), and the obtained images were cropped to include only the BSMs. The FD analysis was performed, and the FD value was obtained by the method of box-counting. Paired t-tests and analysis of variance (ANOVA) were used, and p-values <0.05 was considered statistically significant.

RESULTS

Twelve participants with 22 implants, which were inserted simultaneously after sinus augmentation, were included in this study. A total of 22 mesial, 22 distal, and 14 sagittal images were obtained after FD analysis. The mean FD value and standard deviation at T0 was 1.2860 ± 0.0896, while at T1, it was 1.2508±0.1023; thus, significant differences were detected (p = 0.022). However, the increasing or decreasing trend of FD value was not stable, and no significant difference was detected for FD values of mesial, distal, and sagittal images between T0 and T1. ANOVA indicated that no significant difference was detected among the FD values of mesial, distal, and sagittal images at any timepoint. Differences in FD values between the sexes were not significant either.

CONCLUSIONS

Since the FD analysis for the osteogenesis detection of BSMs in maxillary sinus augmentation indicated unstable trends of change, its feasibility is not reliable. The initially rough surface, self-degradation, and volume change of the BSMs during osteogenesis may be the reason for the variation in FD values.

Evaluation of trabecular bone in individuals with periodontitis using fractal analysis: An observational cross-sectional study

Background

It is very difficult to objectively evaluate the negative changes in bone structure due to periodontitis. The present study was aimed to evaluate the trabecular bone structure between healthy individuals and periodontitis patients by fractal analysis (FA) on digital panoramic radiographs.

Material and Methods

The study included 50 periodontally healthy individuals (control group), 50 individuals with Stage 1 periodontitis (S1-P group), 50 individuals with Stage 2 periodontitis (S2-P), and 50 individuals with Stage 3 periodontitis (S3-P), a total of 200 individuals were included. The fractal dimension (FD) value of the trabecular bone in the interdental space between mandibular first molar and second premolar tooth roots was evaluated using Image J program. The mean FD values of the two regions were calculated by box counting method.

Results

There was a statistically significant difference between the groups in terms of all periodontal parameter values (p<0.05). The mean FD values of individuals diagnosed with periodontitis were 1.36±0.08 in the S1-P group, 1.35±0.07 in the S2-P group, 1.28±0.15 in the S3-P group, and 1.44±0.06 in the control group. When the FD values between the groups were examined, it was seen that there was a statistically significant difference between the control and individuals with periodontitis, and the mean FD values were significantly higher in the healthy group (p<0.05). The best receiver operator curve was identified for periodontitis at the ≤1.409 cut-off FD value (area under the curve: 0.828; 95% CI: 0.758-0.899); p=0.000, p<0.001).

Conclusions

FD evaluation can give an objective result about the effect of periodontitis on alveolar bone. The FD values of trabecular bone are different in healthy individuals and individuals with different stages of periodontitis. The findings suggested that a negative correlation between the periodontal data with the sites in which FD was measured and as the periodontitis stage progresses, FD decreases. Key words:Diagnosis, Periodontal Diseases, Radiographic Evaluation.

Fractal analysis of the mandible cortical bone: correlation among fractal dimension values obtained by two processing methods from periapical radiograph and micro-computed tomography with cone-beam computed tomography

The objectives of the present study were to assess Fractal Dimension (FD) values in the mandible cortical bone obtained from digital periapical radiographs (DPR), high-resolution microtomography (µCT), and cone-beam computed tomography (CBCT), by two processing methods: binarization (FD.b) and grayscale-based method (FD.f) and, finally, to identify the correlation among these values with other micro-architectural parameters. For this, a prospective study was conducted on 18 healthy individuals (mean age 23 ± 2.4 years old) who underwent third molar extraction. Pre-operative CBCT scans were conducted, bone fragments were removed from the retro-molar region, and DPR and µCT were performed on those bone samples. FD.b and FD.f values were calculated using three parasagittal sections for CBCT, one image for DPR, and three sections for µCT. The 3D bone microarchitecture was analyzed in µCT (voxel size: 19 µm). As a result, FD.b mean values of 1.55 ± 0.02 and 1.80 ± 0.01 were obtained for CBCT and µCT, respectively. Furthermore, FD.f mean values of 1.22 ± 0.12 for DPR, 0.99 ± 0.04 for CBCT, and 1.30 ± 0.07 for µCT were obtained. Both FD.b and FD.f values showed a good agreement. FD.f was negatively correlated with the standard deviation of the mean gray value (p = 0.003) for DPR and intra-cortical bone surface (p = 0.02) for µCT. In conclusion, image processing with or without binarization revealed different values for FD, although showing agreement. The grayscale-based method retrieved FD values correlated with the gray levels and the cortical porous network, which means that FD can be a valuable index for mandibular cortical bone evaluation. FD is associated with mineralization and microarchitecture. Nevertheless, there was no correlation between FD values obtained from low- (DPR) and high-resolution (µCT) X-ray modalities with FD obtained from the in vivo CBCT.

Modular Neural Networks for Osteoporosis Detection in Mandibular Cone-Beam Computed Tomography Scans

In this technical note, we examine the capabilities of deep convolutional neural networks (DCNNs) for diagnosing osteoporosis through cone-beam computed tomography (CBCT) scans of the mandible. The evaluation was conducted using 188 patients' mandibular CBCT images utilizing DCNN models built on the ResNet-101 framework. We adopted a segmented three-phase method to assess osteoporosis. Stage 1 focused on mandibular bone slice identification, Stage 2 pinpointed the coordinates for mandibular bone cross-sectional views, and Stage 3 computed the mandibular bone's thickness, highlighting osteoporotic variances. The procedure, built using ResNet-101 networks, showcased efficacy in osteoporosis detection using CBCT scans: Stage 1 achieved a remarkable 98.85% training accuracy, Stage 2 minimized L1 loss to a mere 1.02 pixels, and the last stage's bone thickness computation algorithm reported a mean squared error of 0.8377. These findings underline the significant potential of AI in osteoporosis identification and its promise for enhanced medical care. The compartmentalized method endorses a sturdier DCNN training and heightened model transparency. Moreover, the outcomes illustrate the efficacy of a modular transfer learning method for osteoporosis detection, even when relying on limited mandibular CBCT datasets. The methodology given is accompanied by the source code available on GitLab.

Utility of Cone-Beam Computed Tomography in the Detection of Low Bone Mass-A Systematic Review

INTRODUCTION

Cone-beam computed tomography (CBCT) is widely used in the preoperative qualitative and quantitative assessment of dental implant sites, offering dimensional accuracy, spatial resolution, gray density, and contrast comparable to those of classical CT scan, yet with disputable ability to determine bone mass density.

MATERIALS AND METHODS

A systematic review of the literature was performed using the PubMed and SCOPUS databases, with terms referring to low bone mass and cone-beam computed tomography (CBCT).

RESULTS

Sixteen studies were included in the review. The results show different perspectives, but the evidence favors the use of CBCT, combined with dual-energy X-ray absorptiometry bone density scan (DXA) evaluation, for the assessment of the osteoporosis status of the aging population and, more specifically, in postmenopausal women. Radiographic density (RD) values of the dens and the left part of the first cervical vertebra show the strongest correlation coefficients and the highest sensitivity, specificity, and accuracy for predicting osteoporosis (OP) in the lumbar vertebrae and the femoral neck.

CONCLUSIONS

Our review suggests the potential of CBCT as a screening tool for patients with low bone mass using different radiomorphometric indices. Linear measurements of the inferior mandibular cortex were lower in osteoporotic individuals, indicating the perspective of CBCT also as a diagnostic tool for this disease.

Application of Panoramic Radiography in the Detection of Osteopenia and Osteoporosis-Current State of the Art

PURPOSE OF REVIEW

Osteoporosis ranks high among morbidities in the elderly as it is a natural process to lose bone, making them susceptible to fractures from minor falls. The cost of managing these patients is staggering. The fractures can be prevented with better care of the elderly, and by treating the major predisposing factor, osteoporosis. Clinicians and scientists, in general, constantly look for early diagnostic and prognostic indicators for osteopenia and osteoporosis to proactively prevent fractures. Dental panoramic radiography (DPR) is a rotational pantomography used for identifying dental pathology in patients. Early signs of osteopenia and osteoporosis can be identified in DPR. The usefulness of notable jaw changes in DPR to predict osteopenia and osteoporosis is still evolving as more studies continue to delve into this concept. The purpose of this review is to present advances made in the practical application of DPR for predicting early onset of osteopenia and osteoporosis.

RECENT FINDINGS

Dental panoramic radiography, a form of tomography commonly used by dental practitioners, has been the standard of care for decades for detecting dento-alveolar pathology. Several technological advancements have taken place with respect to the use of DPR. These include conversion from plain film to digital radiography, advancements in the manufacture of flat panel detectors, and accurate imaging of the layers of mandible and maxilla that has become possible with appropriate patient positioning within the focal trough of the machine. Improvements in the software infrastructure make it easier to view, enhance, and save the radiographic images. The radiographic appearance of the trabecular bone within the mandible and indices measured from the dental panoramic radiographs focusing on the inferior cortex of the mandible are considered useful tools for identifying asymptomatic individuals with osteoporosis or at risk for developing osteoporosis. These indices apparently correlate with risks of fragility fractures of osteoporosis in other parts of the body. Dental panoramic radiography (DPR) is a commonly used radiographic procedure in dentistry for evaluation of teeth and associated maxillofacial structures. The evaluation of the inferior border of the mandible for reduction or loss of cortical thickness and evaluation of the trabecular bone within the mandible are helpful markers for early signs of osteopenia to identify patients at risk for osteoporosis. This review focused on research advancements on practical application of DPR in early identification of osteopenia and osteoporosis.

Radiomorphometric indices and fractal dimension of the mandible in individuals with osteogenesis imperfecta: a matched cross-sectional study

OBJECTIVE

The objective was to analyze radiomorphometric indices (RMIs) of mandibular cortical bone and fractal dimension (FD) of trabecular bone of individuals with osteogenesis imperfecta (OI) and compare the findings to those of individuals without OI.

METHODS

Digital panoramic radiographs of 20 individuals with OI (case group) and 40 individuals without OI (control group) were examined. The RMIs of mandibular cortical index (MCI) and mandibular cortical thickness (MCT) were analyzed. FD of mandibular trabecular bone was calculated bilaterally in 3 regions. The chi-squared test and paired t test were used to compare the significance of differences between the groups. The effect size and minimal clinically important difference (MCID) were also determined. Significance was established at P < .05.

RESULTS

Categories C2 and C3 of the MCI were more frequent in individuals with OI (P < .001). The Mean MCT was 2.08 ± 0.79 in the OI case group and 2.91 ± 0.60 in the control group (P < .001). Mean FD in the condylar region was significantly lower in the OI case group (P = .002). The effect size for these 2 measures was large, and the difference between groups was greater than the MCID.

CONCLUSION

Radiographs of individuals with OI exhibited more porosity and diminished thickness of the mandibular cortical bone and lower FD values in the condylar trabecular bone.

Fractal dimension, lacunarity, and cortical thickness in the mandible: Analyzing differences between healthy men and women with cone-beam computed tomography

Purpose

The objective of this study was to assess the fractal dimension, lacunarity, trabecular microarchitecture parameters, and cortical linear measurements in the mandibles of male and female individuals to identify differences between them.

Materials and Methods

In total, 116 cone-beam computed tomography scans of healthy individuals of different ages (57 men and 59 women, aged between 20 and 60 years) were selected. The following bone parameters were measured: 1) buccal, lingual, and basal cortical bone thickness in 5 standard parasagittal sections (the midline, the left and right sides of the lower lateral incisors, and the left and right sides of the lower canines); 2) the bone volume fraction of 10 sequential axial sections from each patient by creating a volume of interest in the area between the lower canines; and 3) fractal dimension and lacunarity using grayscale images of the same region of the volume of interest in the anterior mandible. Spearman correlation coefficients and the Mann-Whitney test were used.

Results

A significant and positive correlation was found between age and cortical thickness, especially in the region of the central incisors. Significant differences between sexes in terms of fractal dimension, lacunarity, and bone volume were found. Women revealed lower fractal dimension values and higher lacunarity and bone volume ratio values than men.

Conclusion

Fractal dimension, lacunarity, trabecular bone volume, and cortical thickness were different between men and women of different ages.

Morphologic Mandibular Bone Changes on Panoramic Radiographs of Children and Adolescents with Congenital Heart Disease

Congenital heart disease (CHD) has effects on growth and development. However, information on how the structure of the mandibular bone is affected is limited. In the present study, we aim to compare mandibular bone structures of children affected with CHD and healthy ones through the fractal analysis method and radiomorphometric indices based on panoramic radiographs. The study consisted of 80 children (20 with cyanotic CHD, 20 with acyanotic CHD, 40 control) who were diagnosed with CHD and were treated through interventional therapy or followed up through medical therapy. Fractal dimension (FD) was performed in three different areas (angulus, corpus, and interdental bone) on 80 panoramic radiographs. Additionally, we assessed various radiomorphometric indices: mandibular cortical width (MCW), panoramic mandibular index (PMI), mandibular cortical index (MCI), and simple visual estimation (SVE). p < 0.05 was accepted as statistically significant in the analysis. Values of mean MCW, PMI, MCI, SVE, and FD measurements in children affected with CHD were found to be similar to the control group, regardless of whether they were cyanotic or acyanotic (p > 0.05). In this study, fractal analysis and radiomorphometric indices revealed no trabecular structure and mineral density changes in mandibular bone of children and adolescents with CHD compared to healthy subjects.

Magnetic resonance imaging and fractal analysis findings in temporomandibular joints with disk perforation

OBJECTIVE

This study compared magnetic resonance imaging (MRI) findings and fractal dimension (FD) values in the temporomandibular joints (TMJs) of study patients with disk perforation vs control patients.

STUDY DESIGN

Of 75 TMJs examined with MRI for characteristics of the disk and condyle, 45 were included in the study group and 30 in the control group. MRI findings and FD values were compared for significance of differences between the groups. The frequency of subclassifications was analyzed for differences between the two forms of disk configuration and grades of effusion. Mean FD values were analyzed for differences among subclassifications of MRI findings and between groups.

RESULTS

Examination of MRI variables revealed that the study group had significantly greater frequencies of flattened disks, disk displacement, flattening and combined defects in condylar morphology, and grade 2 effusion (P = .001) Joints with perforated disks had a large percentage of normal disk-condyle relationships (73.3%). Significant differences were discovered between biconcave and flattened disk configuration in the frequencies of internal disk status and condylar morphology. FD values of all patients varied significantly among the subclassifications of disk configuration, internal disk status, and effusion. Mean FD values were significantly lower in the study group with perforated disks (1.07) compared with the control group (1.20, P = .001).

CONCLUSIONS

MRI variables and FD can be useful in investigating intra-articular TMJ status.

Novel method to delineate palatal rugae and assess their complexity using fractal analysis

Palatal rugae constitute significant morphological landmarks, with wide clinical applications in forensics, insertion of mini-screws, and superimposition. Their morphology has been studied mainly with indices relevant to their qualitative characteristics. The present paper aims at presenting a new quantitative method to evaluate their complexity, by means of box-counting fractal dimension analysis, and to investigate its inter- and intra-rater reliability. Twenty maxillary plaster models were scanned for the needs of this study. A sequence of steps, including cropping of the mesh, ball pivoting, distance mapping and fractal dimension analysis, performed with Viewbox 4 software, was followed. Box-counting fractal dimensions were calculated as a measure of rugae's complexity. Inter- and intra-rater reliability were investigated, using Bland-Altman analysis. Fractal dimensions ranged from 1.274 to 1.491 (average: 1.412). Bland-Altman analysis of inter- and intra-examiner reliability demonstrated that the 95% limits of agreement ranged from - 0.012 to 0.011 and from - 0.004 to 0.004, respectively. The method is reliable and can be applied in research and forensics. It offers comprehensive evaluation of the rugae's complexity and a complete set of information about their outlines and height profiles, with minimum user intervention.

Fractal analysis of dental periapical radiographs: A revised image processing method

OBJECTIVE

To assess trabecular bone structure as calculated with fractal analysis by 2 binarization processes: White and Rudolph's original method (WR.o) and a revised version (WR.r). Fractal dimension (FD) values calculated with WR.r (FD.r) and a gray-scale-based method (FD.f) were also compared. FD, histogram parameters, and lacunarity were compared by dentate status, jaw location, and sex.

STUDY DESIGN

Regions of interest from digital periapical radiographs were defined below the teeth roots and in the edentulous sites of 37 patients. Histograms were assessed for pixel values. Binarization was performed with WR.o and then with WR.r, in which the outliers were removed. FD was assessed using WR.r (FD.r) and (FD.f). Histograms were assessed to obtain pixel values. Lacunarity was calculated.

RESULTS

WR.r revealed fewer trabeculae, branches, and junctions than WR.o (P < .0001). The majority of the mean differences between FD.r and FD.f were within the 95% CI. Dentate areas had greater mean gray levels than partially edentulous areas (P = .0027). FD.f was higher in the mandible (P = .01), but gray-level SD (P < .0001) and lacunarity (P = .02) were greater in the maxilla. FD.f and lacunarity were higher (P = .0005) and lower (P = .0014) in males, respectively.

CONCLUSION

WR.r was effective in revealing skeletonized bone trabeculae by removing non-trabecular noise. FD.r and FD.f revealed good agreement. FD.f, histogram parameters, and lacunarity differed based on dentate status, jaw location, and sex.

Indices in dental image exams for bone mineral density evaluation of aromatase inhibitor users

We evaluated the accuracy of radiomorphometric indices (RI) and fractal dimension (FD) for screening bone mineral density (BMD) in postmenopausal patients who had breast cancer and were using aromatase inhibitors (AI). The sample consisted of 40 participants. Digital panoramic radiography (DPR) and cone beam computed tomography (CBCT) were evaluated along with dual-energy X-ray absorptiometry (DXA), which is the gold standard for detecting low BMD. According to the T-scores of DXA, the subjects were assigned into two groups: with normal BMD and with low BMD (osteopenia and osteoporosis). The area under the curve (AUC), sensitivity, and specificity with their respective confidence intervals were determined for DPR and CBCT. For DPR indices, AUC ranged from 52.6 to 75.8%. The mandibular cortical width (MCW) had the highest AUC. For FD, the total trabecular index had the highest sensitivity, while the index anterior to the mental foramen (MF) had the highest specificity. In CBCT, the AUC ranged from 51.8 to 62.0%. The indices with the highest AUC were the molar (M) and anterior (A). The symphysis (S) index had the highest sensitivity and the posterior (P) index had the highest specificity. Sensitivity and specificity were adequate for the computed tomography index (Inferior; CTI [I]). Therefore, MCW, FD of the mandible angle, and total trabecular ROI in DPR and the CTI (I), M, P, and A indices in CBCT proved to be promising tools in distinguishing individuals with low BMD. Cutoff point for these indices could be a useful tool to investigate low BMD in postmenopausal women taking AI.

The Construction and Evaluation of a Multi-Task Convolutional Neural Network for a Cone-Beam Computed-Tomography-Based Assessment of Implant Stability

Objectives: Assessing implant stability is integral to dental implant therapy. This study aimed to construct a multi-task cascade convolution neural network to evaluate implant stability using cone-beam computed tomography (CBCT). Methods: A dataset of 779 implant coronal section images was obtained from CBCT scans, and matching clinical information was used for the training and test datasets. We developed a multi-task cascade network based on CBCT to assess implant stability. We used the MobilenetV2-DeeplabV3+ semantic segmentation network, combined with an image processing algorithm in conjunction with prior knowledge, to generate the volume of interest (VOI) that was eventually used for the ResNet-50 classification of implant stability. The performance of the multitask cascade network was evaluated in a test set by comparing the implant stability quotient (ISQ), measured using an Osstell device. Results: The cascade network established in this study showed good prediction performance for implant stability classification. The binary, ternary, and quaternary ISQ classification test set accuracies were 96.13%, 95.33%, and 92.90%, with mean precisions of 96.20%, 95.33%, and 93.71%, respectively. In addition, this cascade network evaluated each implant's stability in only 3.76 s, indicating high efficiency. Conclusions: To our knowledge, this is the first study to present a CBCT-based deep learning approach CBCT to assess implant stability. The multi-task cascade network accomplishes a series of tasks related to implant denture segmentation, VOI extraction, and implant stability classification, and has good concordance with the ISQ.

Quantitative Measurement of Swallowing Performance Using Iowa Oral Performance Instrument: A Systematic Review and Meta-Analysis

Swallowing is a complex but stereotyped motor activity aimed at serving two vital purposes: alimentary function and the protection of upper airways. Therefore, any impairment of the swallowing act can represent a significant clinical and personal problem that needs an accurate diagnosis by means of reliable and non-invasive techniques. Thus, a systematic review and meta-analysis was performed to investigate the reliability of the Iowa Oral Pressure Instrument (IOPI) in distinguishing healthy controls (HC) from patients affected by swallowing disorders or pathologies and conditions that imply dysphagia. A comprehensive search was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and using PubMed, Scopus, Web of Science, Cochrane, and Lilacs databases. Overall, 271 articles were identified and, after a three-step screening, 33 case-control and interventional studies reporting IOPI measurements were included. The methodological quality of the retrieved studies resulted in being at a low risk of bias. The meta-analysis on case-control studies showed that maximum tongue pressure (MIP) values were always higher in HC than in patients, with an overall effect of the MIP difference of 18.2 KPa (17.7–18.7 KPa CI). This result was also confirmed when the sample was split into adults and children, although the MIP difference between HC and patients was greater in children than in adults (21.0 vs. 15.4 KPa in the MIP mean difference overall effect, respectively). Tongue endurance (TE) showed conflicting results among studies, with an overall effect among studies near zero (0.7 s, 0.2–1.1 s CI) and a slight tendency toward higher TE values in HC than in patients. Among the intervention studies, MIP values were higher after treatment than before, with a better outcome after the experimental tongue training exercise than traditional treatments (the MIP mean difference overall effect was 10.8 and 2.3 KPa, respectively). In conclusion, MIP values can be considered as a reliable measure of swallowing function in adults and in children, with a more marked MIP difference between HC and patients for the children population. MIP measures in patients are also able to detect the best outcome on the tongue function after the training exercise compared to traditional training.

Does Fractal Analysis Have a Role in Diagnosis of Langerhans Cell Histiocytosis?

PURPOSE

Langerhans cell histiocytosis (LCH) of the jaws is a rare disease and is often diagnosed at an advanced stage. This study aims to assess the trabecular pattern of jaws via fractal analysis (FA) on initial panoramic radiographs (OPG) of the patients with LCH to facilitate interpretation of the radiographic changes.

METHODS

A case-control study investigated LCH cases with jaw involvement retrieved from the databases of Istanbul and Kocaeli Universities between 2010 and 2021. Initial OPGs of LCH cases and OPGs of healthy sex- and age-matched controls were investigated with FA. All images were assessed using ImageJ software. On each OPG, a total of 6 regions of interest (ROIs) located on the mandible were investigated bilaterally. The independent variables were the trabecular patterns of jaws of LCH cases and their control matches. The outcome variables were the fractal dimension (FD) values obtained from the ROIs on OPGs. Data were analyzed using the Mann-Whitney U test and Student's t test.

RESULTS

Fifteen LCH-control pairs were investigated. In one ROI located in the supracortical area above the left mandibular angle, FD values of LCH cases (1.273 ± 112.8) were significantly lower than controls (1.308 ± 85.3; P < .05). Lower FD values were also calculated for some of the remaining ROIs, but there was no significant difference between groups (P > .05).

CONCLUSIONS

Regarding our results, FA was not a useful parameter to discern radiographical trabecular changes between LCH cases and controls. Multicenter studies with larger populations are needed to investigate the potential of FA in the identification of this rare disease.

Cone beam computed tomography analysis of mandibular inferior cortical thickness and bone texture in cemento-osseous dysplasia

OBJECTIVE

This study compared mandibular cortical thickness (CTh) and fractal dimension (FD) in patients with cemento-osseous dysplasia (COD) and controls, as measured with cone beam computed tomography.

STUDY DESIGN

In total, 28 female patients with COD and 28 age-matched controls were selected retrospectively. Inferior cross-sectional CTh was measured at the symphysis (sCTh), anterior (aCTh), mental foramen (mfCTh), molar (mCTh), and posterior (pCTh) regions. The alternate measurement of mean CTh of the volume including buccal, lingual, and inferior cortices between the mental foramina (alternate CTh) was measured in ImageJ. FD was calculated in cortical and trabecular bone. Data were analyzed for significance of differences in CTh and FD between patient groups and for correlation of inferior and alternate CTh measurements.

RESULTS

Inferior CTh values were lower overall in the patients with COD than in the controls (P = .01), specifically at sCTh, mCTh, and pCTh (P ≤ .042). Alternate CTh was also significantly lower in the COD group (P = .005). There was a significant correlation between inferior and alternate CTh measurements (r = 0.636, P < .001). No significant differences were observed in cortical or trabecular FD between groups (P ≥ .072).

CONCLUSIONS

Female patients with COD had significantly lower inferior and alternate CTh than healthy controls. Both groups had similar cortical and trabecular bone textures.

Fractal dimension analysis on CBCT scans for detecting low bone mineral density in postmenopausal women

Purpose

The aim of this study was to compare the fractal dimension (FD) measured at 2 bone sites (second cervical vertebra and mandible) on cone-beam computed tomography (CBCT). The research question was whether FD could serve as an accessory tool to refer postmenopausal women for densitometric analysis. Therefore, the reliability and accuracy of FD were evaluated.

Materials and Methods

In total, 103 postmenopausal women were evaluated, of whom 52 had normal bone mineral density and 51 had osteoporosis, according to dual X-ray absorptiometry of the lumbar spine and hip. On the CBCT scans, 2 regions of interest were selected for FD analysis: 1 at the second cervical vertebra and 1 located at the mandible. The correlations between both measurements, intra- and inter-observer agreement, and the accuracy of the measurements were calculated. A P value less than 0.05 was considered to indicate statistical significance for all tests.

Results

The mean FD values were significantly lower at the mandibular region of interest in osteoporotic patients than in individuals with normal bone mineral density. The areas under the curve were 0.644 (P=0.008) and 0.531 (P=0.720) for the mandibular and vertebral sites, respectively.

Conclusion

FD at the vertebral site could not be used as an adjuvant tool to refer women for osteoporosis investigation. Although FD differed between women with normal BMD and osteoporosis at the mandibular site, it demonstrated low accuracy and reliability.