Mandibular bone changes in 24 years and skeletal fracture prediction

METTL14 promotes TBK1 mRNA stability through IGF2BP3-recognized m6A modification and enhances mitophagy in BMSCs

Osteoporosis, particularly postmenopausal osteoporosis, represents a growing global health challenge characterized by impaired bone remodeling and increased fracture risk. The impairment of bone regeneration manifests in the field of oral and maxillofacial medicine as delayed alveolar bone healing after tooth extraction and poor osseointegration of dental implants, significantly compromising oral functional rehabilitation. This study investigates the role of METTL14 in osteogenic differentiation and its potential regulatory mechanisms in bone metabolism. We identified differential expression patterns of METTL14 in bone marrow-derived mesenchymal stem cells (BMSCs) between osteoporotic patients and healthy controls. Through loss-of-function experiments, we further demonstrated the critical role of METTL14 in promoting osteogenic differentiation, providing direct evidence for its functional importance in bone metabolism regulation. Transcriptome sequencing analysis revealed a significant association between METTL14 and mitophagy. JC-1 assay, Mitosox assay, mt-Keima assay, western blotting and immunofluorescence demonstrated METTL14's positive regulatory role in mitophagy, with TBK1 identified as the most significantly altered downstream target through qRT-PCR and rescue experiments. We further elucidated that IGF2BP3, an m6A reader, promotes osteogenesis and regulates TBK1 mRNA stability, as evidenced by Actinomycin D treatment and mitochondrial-lysosomal colocalization assays. In vivo experiments showed that METTL14 overexpression enhanced alveolar bone healing in ovariectomized osteoporotic mice. These findings provide novel evidence supporting METTL14 as a potential therapeutic target for osteoporosis.

Does low bone mineral density have an association with head and neck soft tissue calcifications?

OBJECTIVES

To evaluate whether low bone mineral density (BMD) has an association with the presence of head and neck soft tissue calcifications (STC), aging, and impaired mandibular canal cortices visibility.

MATERIALS AND METHODS

Panoramic radiographs of 1000 women aged between 50 and 75 years old were evaluated by two examiners to classify BMD using mandibular cortical index (C1- normal, C2-moderately eroded and C3-severely eroded), the presence of STC, and also the mandibular canal cortices visibility at the ramus region. Chi-square test evaluated the association between the variables (α = 5%).

RESULTS

There was no association between bone loss and the presence of head and neck soft tissue calcifications, except for calcified thyroid cartilage, which was less visualized at C3 group than others (p < 0.05). Women aged 61 to 70 years old presented higher bone loss than those between 50 and 60 (p < 0.05). The mandibular canal was more poorly visualized at C3 group than C1 and C2 (p < 0.05).

CONCLUSIONS

In general, no association between BMD and the presence of STC was found. However, greater bone loss had a positive correlation with aging and impaired mandibular canal cortices visibility.

CLINICAL RELEVANCE

No relationship between bone mineral density and the existence of soft tissue calcifications was found. Nevertheless, increased bone loss was positively associated with aging and a reduced mandibular canal cortices visibility. This finding highlights the clinical importance of considering bone density factors when planning treatment strategies for patients with related disorders.

Ultrasound Characterization of Cortical Bone Using Shannon Entropy

OBJECTIVE

Ultrasound backscattered signals encompass information on the microstructure of heterogeneous media such as cortical bone, in which pores act as scatterers and result in the scattering and multiple scattering of ultrasound waves. The objective of this study was to investigate whether Shannon entropy can be exploited to characterize cortical porosity.

METHODS

In the study described here, to demonstrate proof of concept, Shannon entropy was used as a quantitative ultrasound parameter to experimentally evaluate microstructural changes in samples with controlled scatterer concentrations made of a highly absorbing polydimethylsiloxane matrix (PDMS). Similar assessment was then performed using numerical simulations on cortical bone structures with varying average pore diameter (Ct.Po.Dm.), density (Ct.Po.Dn.) and porosity (Ct.Po.).

RESULTS

The results suggest that an increase in pore diameter and porosity lead to an increase in entropy, indicating increased levels of randomness in the signals as a result of increased scattering. The entropy-versus-scatterer volume fraction in PDMS samples indicates an initial increasing trend that slows down as the scatterer concentration increases. High levels of attenuation cause the signal amplitudes and corresponding entropy values to decrease drastically. The same trend is observed when porosity of the bone samples is increased above 15%.

CONCLUSION

Sensitivity of entropy to microstructural changes in highly scattering and absorbing media can potentially be exploited to diagnose and monitor osteoporosis.

The outcome of an automated assessment of trabecular pattern in intraoral radiographs as a fracture risk predictor

OBJECTIVES

This study aims to investigate if automated analyses of the trabecular pattern in intraoral radiographs independently contribute to fracture risk assessment when other risk factors incorporated in the Fracture Risk Assessment Tool (FRAX) are taken into account. A secondary aim is to explore the correlation between the automated trabecular pattern assessment in intraoral radiographs and Trabecular Bone Score (TBS).

METHODS

A total of 567 intraoral radiographs from older females participating in a large population-based study (SUPERB) based in Gothenburg, Sweden, were selected to analyse trabecular pattern using semi-automated and fully automated software. Associations between trabecular pattern analysis and incident fractures were studied using Cox proportional hazard model, unadjusted and adjusted for FRAX risk factors (previous fracture, family history of hip fracture, smoking, corticosteroids, rheumatoid arthritis, without and with bone mineral density (BMD) of the femoral neck). In addition, the correlation between trabecular pattern analysis and TBS of the lumbar spine was investigated using Pearson correlation analysis.

RESULTS

Neither the unadjusted nor the adjusted trabecular pattern analysis in intraoral radiographs was significantly associated with any fracture or major osteoporotic fracture (MOF). A weak correlation was found between semi-automated trabecular pattern analysis and TBS. No correlation was found between the fully automated trabecular pattern analysis and TBS.

CONCLUSIONS

The present study shows that semi-automated and fully automated digital analyses of the trabecular pattern in intraoral radiographs do not contribute to fracture risk prediction. Furthermore, the study shows a weak correlation between semi-automated trabecular pattern analysis and TBS.

Osteoporosis and periodontal diseases - An update on their association and mechanistic links

Periodontitis and osteoporosis are prevalent inflammation-associated skeletal disorders that pose significant public health challenges to our aging population. Both periodontitis and osteoporosis are bone disorders closely associated with inflammation and aging. There has been consistent intrigue on whether a systemic skeletal disease such as osteoporosis will amplify the alveolar bone loss in periodontitis. A survey of the literature published in the past 25 years indicates that systemic low bone mineral density (BMD) is associated with alveolar bone loss, while recent evidence also suggests a correlation between clinical attachment loss and other parameters of periodontitis. Inflammation and its influence on bone remodeling play critical roles in the pathogenesis of both osteoporosis and periodontitis and could serve as the central mechanistic link between these disorders. Enhanced cytokine production and elevated inflammatory response exacerbate osteoclastic bone resorption while inhibiting osteoblastic bone formation, resulting in a net bone loss. With aging, accumulation of oxidative stress and cellular senescence drive the progression of osteoporosis and exacerbation of periodontitis. Vitamin D deficiency and smoking are shared risk factors and may mediate the connection between osteoporosis and periodontitis, through increasing oxidative stress and impairing host response to inflammation. With the connection between systemic and localized bone loss in mind, routine dental exams and intraoral radiographs may serve as a low-cost screening tool for low systemic BMD and increased fracture risk. Conversely, patients with fracture risk beyond the intervention threshold are at greater risk for developing severe periodontitis and undergo tooth loss. Various Food and Drug Administration-approved therapies for osteoporosis have shown promising results for treating periodontitis. Understanding the molecular mechanisms underlying their connection sheds light on potential therapeutic strategies that may facilitate co-management of systemic and localized bone loss.

Mandibular cortical bone structure as risk indicator in fractured and non-fractured 80-year-old men and women

Objective

To investigate the association between mandibular cortex parameters and fracture in a group of 286 men and women, 79–80 years of age.

Study design

In a cross-sectional study, the mandibular cortex was evaluated with Klemetti’s index for cortical erosion. The cortical thickness was measured with a ruler adjusting for the magnification factor. The odds ratio (OR) for fracture when having a severely eroded cortex or a cortex thickness < 3 mm was calculated.

Results

A normal cortex was found in 65% of men, whereas only 7% had a severely eroded cortex. The OR for severely eroded cortex  as fracture risk predictor was significant (2.32; 95% CI 1.3–4.2), also when the female group was evaluated separately. A significant difference was found between the mean thickness for men (3.96 mm) and women (2.92 mm), respectively. The OR for cortical thickness < 3 mm was significant (2.00; 95% CI 1.1–3.6) in the total group, but not when men and women were evaluated separately.

Conclusions

Among old women, the cortical parameters were significantly associated with prevalent fracture. In old men, other circumstances may be more important.

An experimental study on the effects of the cortical thickness and bone density on initial mechanical anchorage of different Straumann® implant designs

Background

The aim of the current study was to comparatively assess the primary stability of different Straumann® implant designs (BLX, Straumann Tapered Effect, Bone Level Tapered, and Standard Plus) via resonance frequency analysis by using an implant insertion model in freshly slaughtered bovine ribs with and without cortical bone. Tapered Effect (4.1 × 10 mm), Bone Level Tapered (4.1 × 10 mm), Standard Plus (4.1 × 10 mm), and BLX (4.0 × 10 mm) implants were inserted into the distal epiphysis on the longitudinal axis of the freshly slaughtered bovine ribs. As a control, implants with the same sizes were inserted into the proximal diaphysis. The stability of the implants was examined with resonance frequency analysis.

Results

BLX and Tapered Effect implants showed higher implant stability quotient values in both study and control groups. All implant systems showed a significant decrease of mechanical anchorage in the study group. BLX and Bone Level Tapered designs had a significantly lower loss of mechanical anchorage in the lack of cortical bone.

Conclusion

Both Tapered Effect and BLX designs could ensure sufficient initial stability; however, BLX implants could be an appropriate option in the lack of cortical bone and poor bone quality at the implant recipient site.

Clinical relevance

BLX is a novel implant system, which could be especially beneficial in the presence of spongious bone type at posterior maxillae.

Inflammasomes in Alveolar Bone Loss

Bone remodeling is tightly controlled by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Fine tuning of the osteoclast-osteoblast balance results in strict synchronization of bone resorption and formation, which maintains structural integrity and bone tissue homeostasis; in contrast, dysregulated bone remodeling may cause pathological osteolysis, in which inflammation plays a vital role in promoting bone destruction. The alveolar bone presents high turnover rate, complex associations with the tooth and periodontium, and susceptibility to oral pathogenic insults and mechanical stress, which enhance its complexity in host defense and bone remodeling. Alveolar bone loss is also involved in systemic bone destruction and is affected by medication or systemic pathological factors. Therefore, it is essential to investigate the osteoimmunological mechanisms involved in the dysregulation of alveolar bone remodeling. The inflammasome is a supramolecular protein complex assembled in response to pattern recognition receptors and damage-associated molecular patterns, leading to the maturation and secretion of pro-inflammatory cytokines and activation of inflammatory responses. Pyroptosis downstream of inflammasome activation also facilitates the clearance of intracellular pathogens and irritants. However, inadequate or excessive activity of the inflammasome may allow for persistent infection and infection spreading or uncontrolled destruction of the alveolar bone, as commonly observed in periodontitis, periapical periodontitis, peri-implantitis, orthodontic tooth movement, medication-related osteonecrosis of the jaw, nonsterile or sterile osteomyelitis of the jaw, and osteoporosis. In this review, we present a framework for understanding the role and mechanism of canonical and noncanonical inflammasomes in the pathogenesis and development of etiologically diverse diseases associated with alveolar bone loss. Inappropriate inflammasome activation may drive alveolar osteolysis by regulating cellular players, including osteoclasts, osteoblasts, osteocytes, periodontal ligament cells, macrophages, monocytes, neutrophils, and adaptive immune cells, such as T helper 17 cells, causing increased osteoclast activity, decreased osteoblast activity, and enhanced periodontium inflammation by creating a pro-inflammatory milieu in a context- and cell type-dependent manner. We also discuss promising therapeutic strategies targeting inappropriate inflammasome activity in the treatment of alveolar bone loss. Novel strategies for inhibiting inflammasome signaling may facilitate the development of versatile drugs that carefully balance the beneficial contributions of inflammasomes to host defense.

Two methods of evaluating mandibular trabecular pattern in intraoral radiographs and the association to fragility fractures during a 47-year follow up

In this longitudinal cohort study, we explored the association of fragility fractures to sparse trabecular bone pattern in intraoral radiographs using two methods, a visual and a semi-automated. Our aim was to study both sexes and to include younger age-groups, during a follow-up time of 47 years. The cohort consisted of 837 men and women aged 18-65 years, with intraoral radiographs from 1970-1971. The trabecular pattern was assessed in the mandibular premolar region with a visual and a semi-automated method. Data on fragility fractures were acquired from the Swedish National Patient Register for 47 years of follow-up time. Sparse trabecular pattern was found in 2.2% of the cohort using the visual method, and 18% were deemed at 'risk of osteoporosis' using the semi-automated method. A total of 132 individuals suffered at least one fragility fracture during the follow-up period. We found no significant association between fractures and sparse trabecular pattern using either method. This study shows that visual assessment, as a predictor of future fractures, may not be a suitable method for individuals of all ages and sexes. As for the semi-automated method, there is still very limited evidence for its fracture predictive ability.

Clinical guidelines for the application of panoramic radiographs in screening for osteoporosis

Osteoporotic fractures are associated with an increased risk of subsequent fractures, a higher rate of mortality, and incremental medical costs. Incidental findings, which include some measurements related to the mandibular inferior cortex and the alveolar trabecular bone pattern of the mandible determined on panoramic radiographs, are considered to be a useful tool for identifying asymptomatic individuals at risk of having osteoporosis and/or fragility fractures. We undertook a worldwide literature survey and present the following clinical recommendations. Postmenopausal female dental patients with a mandibular inferior cortical width of less than 3 mm on panoramic radiographs may be at risk of having low skeletal bone mineral density (BMD) or osteoporosis, but not fragility fractures. In addition, those with a severely eroded mandibular inferior cortex may have an increased risk of having low skeletal BMD, osteoporosis, and fragility fractures. The alveolar trabecular bone pattern of the mandible might be useful for identifying female dental patients at risk of having fragility fractures, although further investigation is necessary to confirm this possibility. These incidental findings on panoramic radiographs, when used for identifying asymptomatic postmenopausal female patients at risk of having osteoporosis in general dental practice, may be helpful in reducing the incidence of first fractures, with a consequent reduction in the secondary fractures, medical costs, and mortality associated with osteoporotic fragility fractures, without incurring any additional cost.

Changing trabecular patterns in panoramic radiographs of Swedish women during 25 years of follow-up

OBJECTIVES

The radiographic trabecular pattern on dental radiographs may be used to predict fractures. The aim of this study was to analyze longitudinal changes in the mandibles of 145 females between 1980 and 2005.

METHODS

Panoramic radiographs were obtained in 1980 and 2005. On 290 radiographs, regions of interest (ROIs) were selected in the ramus, angle and body. In all ROIs, the orientation was measured in 36 directions with the line frequency deviation method. The effects of ageing were analyzed for the fracture and the non-fracture groups separately.

RESULTS

During the follow-up, 61 females suffered fractures of the hip, wrist, spine, leg or arm. The fracture and non-fracture groups displayed dissimilar age changes in each investigated ROI. All significant changes pertained to increasing values of line frequency deviation. With increasing age, the trabecular network in the mandible lost details and the trabeculae became more aligned in their main direction. In the "ramus", the alignment was to the 110-120˚ axis, parallel to the posterior and anterior ramus border. In the "angle", the alignment was to the 135-150˚ axis, parallel to the oblique line, and in the "body" ROI to the 150-175˚ direction, approximately parallel to the occlusal plane and inferior cortex.

CONCLUSION

Most changes were consistent with the notion that the bone aged less severely in the non-fracture group. In the fracture group, the findings indicate that bone loss leads to redistribution of the remaining bone tissue in such a way that the trabeculae are accentuated perpendicular to the principal loading.

Osteoporosis risk assessment in primary dental care-The attitudes of Swedish dentists, patients and medical specialists

OBJECTIVE

To explore and identify the attitudes of dentists, patients and medical specialists regarding implementation of osteoporosis risk assessment into Swedish primary dental care.

BACKGROUND

Osteoporosis is a major health problem leading to fragility fractures. As shown in academic-based research, dental radiological examination can be used for osteoporosis risk assessment. A substantial number of patients undergo radiographic examinations in primary dental care each year, but little is known about implementation of osteoporosis risk assessment in this setting.

MATERIALS AND METHODS

A qualitative research approach using focus group discussions and manifest content analysis was applied. Five focus groups with dentists and representatives from patient support groups and a single individual interview with one medical specialist were included in the sample.

RESULTS

From the manifest content analysis, three categories emerged: (a) barriers to change in practice, (b) benefits to change in practice, and (c) needs and requirements prior to change in practice. Most participants felt that there was insufficient knowledge of osteoporosis as well as a heavy existing workload. A concern was expressed about medical practitioners' willingness to take on responsibility for patients referred by dentists. Representatives from patient support groups highlighted a lack of knowledge about osteoporosis among both the general public and the medical professionals. Clear guidelines and improved communication channels between stakeholders would have to be established to ensure a smooth treatment path for patients.

CONCLUSION

Despite interest in osteoporosis risk assessment in primary dental care, there are political, workflow and educational barriers that must be overcome for successful implementation.

Usefulness of measuring radiographic density of axis vertebra in patients at risk of osteoporosis: A cone-beam computed tomography study

Objective:

Using cone-beam computed tomography (CBCT) images, the aim of the study was to evaluate the usefulness of measuring radiographic density of the axis vertebra (RDAV) in patients at risk of osteoporosis.

Materials and Methods:

Two hundred and forty-seven old patients (109 males and 138 females) aged between 50 and 80 years (mean age: 59.68 ± 7.27) were examined by CBCT. Using InVivoDental, v. 5.0 (Anatomage Inc., San Jose, CA), RDAV and mental index (MI) were measured twice and correlated using Pearson's correlation coefficients. Patients were divided into two categories: high risk and low risk of osteoporosis using 3.1 mm of MI as a cutoff value, and the mean value of RDAV was compared and correlated using independent samples’ t-test and regression analysis. Receiver-operating characteristic (ROC) curve analysis was also used to examine the predictive power of RDAV.

Results:

The mean value of RDAV was moderately correlated with MI (r = 0.32), and in patients at low risk of osteoporosis, the mean value of RDAV was significantly higher than in patients at high risk of osteoporosis. In multivariate binary logistic regression, the odds of being at risk of osteoporosis decreased by 1% with one unit increase in RDAV (odds ratio = 0.988, 95% confidence interval: 0.983–0.993; P < 0.005). ROC analysis showed that the mean value of RDAV had a high predictive power for predicting patients at risk of osteoporosis (area under the curve = 0.761 for females and 0.649 for males).

Conclusions:

Measuring RDAV is considered useful in predicting patients at risk of osteoporosis.

The rise and fall of the alveolar process: Dependency of teeth and metabolic aspects

The alveolar bone has a unique capacity to follow the teeth's movements. It is formed around erupting teeth and their periodontal ligaments: the more the teeth have erupted, the larger the alveolar process. Throughout life the teeth erupt and migrate in an occlusal and mesial direction to compensate for attrition, an evolutionary trait. After tooth extraction, the alveolar process is resorbed to varying degrees. The mandibular alveolar bone mirrors skeletal bone condition. Due to fast bone turnover (which is the fastest in the whole skeleton), low bone mass and increased fracture risk may first be seen here. If a periapical radiograph of the mandibular premolars shows a dense trabeculation with well-mineralized trabeculae and small intertrabecular spaces, it is a reliable sign of normal skeletal bone density (BMD) and low skeletal fracture risk, whereas a sparse trabecular pattern indicates osteopenia and high fracture risk. The bone turnover rate in the mandible is twice that of the maxilla, and may, hypothetically, play a role in the development of osteonecrosis of the jaw (ONJ), which has been found mainly in the mandibular alveolar process?

Usefulness of measuring bone density of mandibular condyle in patients at risk of osteoporosis: A cone beam computed tomography study

Objective:

Using cone beam computed tomography (CBCT) images, the aim of the study was to evaluate the usefulness of measuring bone density of mandibular condyle (BDMC) in patients at risk of osteoporosis.

Materials and Methods:

Two hundred and four mandibular condyles (46 condyles from males and 158 condyles from females) were examined by CBCT. Using inVivo software (Anatomage, San Jose, Calif), BDMC and mental index (MI) were measured by two observers and correlated using Pearson's correlation coefficients. Patients were divided into high risk and low risk of osteoporosis using 3.1 mm of MI as a cutoff value, and the mean value of BDMC was compared and correlated using independent samples t-test and regression analysis. Receiver-operating characteristic (ROC) curve analyses were also used to examine the predictive power of BDMC.

Results:

The mean value of BDMC was moderately correlated with MI (r = 0.38), and in female patients at low risk of osteoporosis, the mean value of BDMC was significantly higher than in patients at high risk of osteoporosis. In multivariate linear regression analysis, being at risk of osteoporosis is significantly affected by BDMC, age, and gender. ROC analysis showed that the mean value of BDMC had a moderate predictive power for predicting patients at risk of osteoporosis (area under the curve = 0.621 for females and 0.649 for males).

Conclusions:

Measuring BDMC is considered useful in predicting patients at risk of osteoporosis.

Evaluation of clinical and radiographic indices as predictors of osteoporotic fractures: a 10-year longitudinal study

OBJECTIVES

The aim of the study was to evaluate 2 radiographic and 3 clinical indices as predictors of future osteoporotic fractures.

STUDY DESIGN

In a prospective, longitudinal study with a 10-year fracture follow-up, the 2 radiographic indices mandibular cortical erosion (normal, mild/moderate erosion, and severe erosion of the inferior cortex) and cortex thickness were assessed using panoramic radiographs of 411 women, age 62 to 78 years. The clinical indices were the fracture assessment tool FRAX, the osteoporosis index of risk (OSIRIS), and the osteoporosis self-assessment tool (OST).

RESULTS

The relative risks (RRs) for future fracture were significant for FRAX greater than 15%, 4.1 (95% confidence interval [CI] 2.4-7.2), and for severely eroded cortices, 1.7 (95% CI 1.1-2.8). Cortical thickness less than 3 mm, OSIRIS, and OST were not significant fracture predictors (RR 1.1, 1.4, and 1.5, respectively). For the 5 tested fracture predictors, Fisher's exact test gave the following P values for differences between fracture and nonfracture groups: FRAX <.001, cortical erosion 0.023, OST 0.078, OSIRIS 0.206, and cortical thickness 0.678. The area under the curve was 0.69 for FRAX less than 15%, 0.58 for cortical erosion, and 0.52 for cortical thickness. Adding OSIRIS and OST did not change the area under the curve significantly.

CONCLUSIONS

FRAX and severely eroded cortices predicted fracture but cortical thickness, OSIRIS, and OST did not.

Predicting fractures using trabecular patterns on panoramic radiographs

OBJECTIVES

The observer score of the trabecular pattern on panoramic radiographs is known to be a strong predictor of bone fractures. The aim of this study was to enhance the predictive power of panoramic radiographs by means of texture analysis methods.

MATERIAL AND METHODS

The study followed 304 postmenopausal women during 26 years. At the beginning of the study, panoramic radiographs were obtained. One observer assessed the trabecular pattern in the premolar region as dense, sparse, or alternating dense and sparse. In addition, on each radiograph, a region of interest was selected in the molar/premolar region and analyzed with texture analysis procedures. During 26 years of follow-up, 115 women suffered a fracture of the hip, spine, leg, or arm. Logistic regression was applied to test the predictive power of various variables with respect to fractures.

RESULTS

Of all variables, the observer score of the trabecular pattern correlated strongest with the occurrence of fractures. By itself, the score yielded an ROC curve with an area of 0.80 under the curve. Combining the observer score with the texture analysis features increased the area under the ROC curve to 0.85.

CONCLUSIONS

The trabecular pattern on panoramic radiographs provides a strong predictor of fractures, at least for postmenopausal women. The assessment by an observer combined with texture analysis procedures yields a predictive power that parallels best known predictions in literature.

CLINICAL RELEVANCE

This study illustrates that panoramic radiographs are state of the art predictors of postcranial fractures.

Assessment of the changes in alveolar bone quality after fixed orthodontic therapy: A trabecular structure analysis

Background. Tooth displacement changes the periodontium. The aim of orthodontic treatment is desired tooth movement with minimum side effects on the alveolar bone quality. The aim of the present study was to assess changes of alveolar trabeculation in children, young adults and adults and the two genders.

Methods. In this cross-sectional study, 63 patients who had been treated in Department of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran, were chosen with convenient sampling method. They were divided into three groups based on their age. Their digitized panoramic radiographs (PRs) were evaluated at six interdental sites from the mesial aspect of the mandibular second molars to the distal aspect of the mandibular first premolars using a visual index. The trabeculation pattern was assigned as either dense (score 3), dense-sparse (score 2) or sparse (score 1). Data were imported to SPSS. Mean of the scores before treatment (score B) and mean of them after treatment (score A) were compared for each group with paired t-test. Changes between score B and sore A of the groups were compared using one-way ANOVA and post hoc tests.

Results. Mean score A was significantly higher than mean score B in children (P = 0.001). In contrast, mean score A was significantly lower than mean score B in young adults (P = 0.003).

Conclusion. Orthodontists should be cautious when treating young adults and adults regarding the probable, yet possibly temporary, negative effects of orthodontic therapy on the alveolar bone quality.

IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices

Purpose

The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening.

Materials and Methods

A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS.

Results

The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%).

Conclusion

IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices.

Comparison of mandibular cortical thickness and QCT-derived bone mineral density (BMD) in survivors of childhood acute lymphoblastic leukemia: a retrospective study

OBJECTIVE

To examine whether panoramic radiograph-determined mandibular cortical thickness correlated with quantitative computed tomography-derived bone mineral density (BMD) in survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

We identified patients treated for ALL at St. Jude Children's Research Hospital, seen in the After Completion of Therapy (ACT) Clinic between January of 2006 and January of 2014 who had QCT-derived BMD and panoramic radiographs obtained within 1 month of each other. Panoramic radiographs were independently scored by a pediatric radiologist, two pediatric dentists, and a general dentist using the Klemetti technique. We used the Spearman's rank correlation test and the multivariate regression model to investigate the effect of evaluator experience on results.

RESULTS

The study cohort comprised 181 patients with 320 paired studies: 112 (62%) male, 112 (71%) were white. Median age at ALL diagnosis was 6.4 (range, 0-18.8) years. Median age at study was 11.9 (range, 3.3 to 29.4) years. The median average BMD was 154.6 (range, 0.73-256) mg/cc; median QCT Z-score (age and gender adjusted) was -0.875 (range, -5.04 to 3.2). We found very weak association between panoramic radiograph score and both QCT-BMD average (P = 0.53) and QCT Z-score (P = 0.39). Results were not influenced by level of reader experience.

CONCLUSIONS

The Klemetti technique of estimating BMD does not predict BMD deficits in children and young adult survivors of ALL, regardless of reviewer expertise. Alternative methods are needed whereby dental healthcare providers can identify and refer patients at risk for BMD deficits for detailed assessment and intervention.

Predicting Trabecular Bone Stiffness from Clinical Cone-Beam CT and HR-pQCT Data; an In Vitro Study Using Finite Element Analysis

Stiffness and shear moduli of human trabecular bone may be analyzed in vivo by finite element (FE) analysis from image data obtained by clinical imaging equipment such as high resolution peripheral quantitative computed tomography (HR-pQCT). In clinical practice today, this is done in the peripheral skeleton like the wrist and heel. In this cadaveric bone study, fourteen bone specimens from the wrist were imaged by two dental cone beam computed tomography (CBCT) devices and one HR-pQCT device as well as by dual energy X-ray absorptiometry (DXA). Histomorphometric measurements from micro-CT data were used as gold standard. The image processing was done with an in-house developed code based on the automated region growing (ARG) algorithm. Evaluation of how well stiffness (Young's modulus E3) and minimum shear modulus from the 12, 13, or 23 could be predicted from the CBCT and HR-pQCT imaging data was studied and compared to FE analysis from the micro-CT imaging data. Strong correlations were found between the clinical machines and micro-CT regarding trabecular bone structure parameters, such as bone volume over total volume, trabecular thickness, trabecular number and trabecular nodes (varying from 0.79 to 0.96). The two CBCT devices as well as the HR-pQCT showed the ability to predict stiffness and shear, with adjusted R2-values between 0.78 and 0.92, based on data derived through our in-house developed code based on the ARG algorithm. These findings indicate that clinically used CBCT may be a feasible method for clinical studies of bone structure and mechanical properties in future osteoporosis research.

Relation between osteoporosis and radiographic and clinical signs of osteoarthritis/arthrosis in the temporomandibular joint: a population-based, cross-sectional study in an older Swedish population

OBJECTIVE

The aim was to elucidate the relation between osteoporosis and osteoarthritis/arthrosis (OA) in the temporomandibular joint (TMJ).

BACKGROUND

General epidemiological data support the hypothesis that osteoporosis and OA are inversely correlated but is not conclusively investigated in the TMJ.

MATERIALS AND METHODS

A group of 114 representative elderly women and men, randomised from a comprehensive population study in Gothenburg, Sweden, had bone mineral density established with whole-body, dual-energy X-ray absorptiometry (DXA) as part of a health survey. In addition, dental examinations were performed, including panoramic radiographs exposed as an overview of the TMJ's and jaws. In 88 of the 80-year-old participants (48 women and 40 men), a clinical orofacial examination according to the RDC/TMD system was performed.

RESULTS

A diagnosis of osteopenia/osteoporosis was found in 36% of the 114, with a statistically different greater proportion of women. Condylar alterations evaluated from panoramic radiographs were observed in 34%, with no significant gender difference. No significant differences were found in the proportion of individuals with osteopenia/osteoporosis and any condylar radiographic alteration or not. Forty-one of the clinically examined subjects, 47%, fulfilled the criteria for an RDC/TMD diagnosis with no gender difference. All participants graded the orofacial pain as low chronic pain. An opening capacity of <40 mm denoted a higher risk of having pain in the temporomandibular system. No association was found between clinical diagnosis of RDC/TMD and osteopenia/osteoporosis.

CONCLUSION

The prevalence of osteopenia/osteoporosis appears not to be of importance for radiological or clinical findings of OA in the TMJ.

Alveolar bone loss in osteoporosis: a loaded and cellular affair?

Maxillary and mandibular bone mirror skeletal bone conditions. Bone remodeling happens at endosteal surfaces where the osteoclasts and osteoblasts are situated. More surfaces means more cells and remodeling. The bone turnover rate in the mandibular alveolar process is probably the fastest in the body; thus, the first signs of osteoporosis may be revealed here. Hormones, osteoporosis, and aging influence the alveolar process and the skeletal bones similarly, but differences in loading between loaded, half-loaded, and unloaded bones are important to consider. Bone mass is redistributed from one location to another where strength is needed. A sparse trabeculation in the mandibular premolar region (large intertrabecular spaces and thin trabeculae) is a reliable sign of osteopenia and a high skeletal fracture risk. Having dense trabeculation (small intertrabecular spaces and well-mineralized trabeculae) is generally advantageous to the individual because of the low fracture risk, but may imply some problems for the clinician.

Botulinum toxin in masticatory muscles of the adult rat induces bone loss at the condyle and alveolar regions of the mandible associated with a bone proliferation at a muscle enthesis

In man, botulinum toxin type A (BTX) is injected in masticatory muscles for several indications such as trismus, bruxism, or masseter hypertrophy. Bone changes in the mandible following BTX injections in adult animal have therefore became a subject of interest. The aim of this study was to analyze condylar and alveolar bone changes following BTX unilateral injections in masseter and temporal muscles in adult rats. Mature male rats (n = 15) were randomized into 2 groups: control (CTRL; n = 6) and BTX group (n= 9). Rats of the BTX group received a single injection of BTX into right masseter and temporal muscles. Rats of the CTRL group were similarly injected with saline solution. Rats were sacrificed 4 weeks after injections. Masticatory muscles examination and microcomputed tomography (microCT) were performed. A significant difference of weight was found between the 2 groups at weeks 2, 3 and 4 (p < 0.05). Atrophy of the right masseter and temporal muscles was observed in all BTX rats. MicroCT analysis showed significant bone loss in the right alveolar and condylar areas in BTX rats. Decrease in bone volume reached -20% for right alveolar bone and -35% for right condylar bone. A hypertrophic bone metaplasia at the digastric muscle enthesis was found on every right hemimandible in the BTX group and none in the CTRL group. BTX injection in masticatory muscles leads to a significant and major mandible bone loss. These alterations can represent a risk factor for fractures in human. The occurrence of a hypertrophic bone metaplasia at the Mus Digastricus enthesis may constitute an etiological factor for tori.

Five-year alveolar bone level changes in women of varying skeletal bone mineral density and bone trabeculation

OBJECTIVES

To investigate alveolar bone level changes in women with varying skeletal bone mineral density (BMD) and bone trabeculation.

STUDY DESIGN

In a prospective, longitudinal study of 128 women (22-75 years of age), BMD (dual x-ray absorptiometry), and periapical radiography were performed in 1996 and 2001. The mandibular trabecular bone was assessed as dense, mixed, or sparse. Mandibular alveolar bone level was measured with a Schei ruler and related to BMD (osteoporotic, osteopenic, or normal) and trabeculation.

RESULTS

After 5 years, the total bone level score was significantly decreased (P = .001). No significant differences were found in the total bone level scores between the different BMD groups. The greatest decreased total bone level score in 1996 was found in the group with dense trabeculation (0.71 in the dense group vs. 0.31 in the nondense group, P = .005), and similarly in 2001 (0.75 in the dense group vs. 0.39 in the nondense group, P = .020). Five-year changes in the total bone level scores did not differ between trabeculation groups (P = .37).

CONCLUSIONS

The small group of women with dense mandibular trabecular bone seems to suffer a greater decrease in alveolar bone height compared with other women, including women with osteoporosis.

Panoramic radiography measurements, osteoporosis diagnoses and fractures in Japanese men and women

OBJECTIVES

The purpose of this study was to investigate the association of the shape of the mandibular cortex on panoramic radiographs with the risk of an osteoporosis diagnosis without prevalent fractures and with the risk of osteoporotic fractures in Japanese men and women.

SUBJECTS AND METHODS

One thousand and twenty-one subjects aged 40-89 years, who visited our university hospital and underwent panoramic radiography between 2007 and 2013, participated in this study. Eighty-eight patients received a diagnosis of osteoporosis without prevalent fractures, and 55 were diagnosed with osteoporotic fractures. Blinded to the groupings, we classified the shape of the mandibular cortex on panoramic radiographs as normal, moderately eroded or severely eroded.

RESULTS

After adjustment for confounding factors, the odds ratios for an osteoporosis diagnosis associated with moderately eroded and severely eroded mandibular cortices were 1.4 (95% CI, 0.8-2.6) and 2.6 (95% CI, 1.4-5.0), respectively. The odds ratios for an osteoporotic fracture associated with moderately eroded and severely eroded cortices were 0.8 (95% CI, 0.4-1.7) and 1.1 (95% CI, 0.5-2.5), respectively.

CONCLUSIONS

Subjects in Japan with eroded mandibular cortices tended to be at increased risk of osteoporosis diagnoses but not of fractures.

Trabecular bone histomorphometric measurements and contrast-to-noise ratio in CBCT

OBJECTIVES

The aim of this study was to evaluate how imaging parameters at clinical dental CBCT affect the accuracy in quantifying trabecular bone structures, contrast-to-noise ratio (CNR) and radiation dose.

METHODS

15 radius samples were examined using CBCT (Accuitomo FPD; J. Morita Mfg., Kyoto, Japan). Nine imaging protocols were used, differing in current, voltage, rotation degree, voxel size, imaging area and rotation time. Radiation doses were measured using a kerma area product-meter. After segmentation, six bone structure parameters and CNRs were quantified. Micro-CT (μCT) images with an isotropic resolution of 20 μm were used as a gold standard.

RESULTS

Structure parameters obtained by CBCT were strongly correlated to those by μCT, with correlation coefficients >0.90 for all studied parameters. Bone volume and trabecular thickness were not affected by changes in imaging parameters. Increased tube current from 5 to 8 mA, decreased isotropic voxel size from 125 to 80 μm and decreased rotation angle from 360° to 180° affected correlations for trabecular termini negatively. Decreasing rotation degree also weakened correlations for trabecular separation and trabecular number at 80 μm voxel size. Changes in the rotation degree and tube current affected CNR significantly. The radiation dose varied between 269 and 1153 mGy cm(2).

CONCLUSIONS

Trabecular bone structure can be accurately quantified by clinical dental CBCT in vitro, and the obtained structure parameters are strongly related to those obtained by μCT. A fair CNR and strong correlations can be obtained with a low radiation dose, indicating the possibility for monitoring trabecular bone structure also in vivo.

Mandibular bone structure, bone mineral density, and clinical variables as fracture predictors: a 15-year follow-up of female patients in a dental clinic

OBJECTIVE

To compare three mandibular trabeculation evaluation methods, clinical variables, and osteoporosis as fracture predictors in women.

STUDY DESIGN

One hundred and thirty-six female dental patients (35-94 years) answered a questionnaire in 1996 and 2011. Using intra-oral radiographs from 1996, five methods were compared as fracture predictors: (1) mandibular bone structure evaluated with a visual radiographic index, (2) bone texture, (3) size and number of intertrabecular spaces calculated with Jaw-X software, (4) fracture probability calculated with a fracture risk assessment tool (FRAX), and (5) osteoporosis diagnosis based on dual-energy-X-ray absorptiometry. Differences were assessed with the Mann-Whitney test and relative risk calculated.

RESULTS

Previous fracture, gluco-corticoid medication, and bone texture were significant indicators of future and total (previous plus future) fracture. Osteoporosis diagnosis, sparse trabeculation, Jaw-X, and FRAX were significant predictors of total but not future fracture.

CONCLUSION

Clinical and oral bone variables may identify individuals at greatest risk of fracture.

Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

OBJECTIVE

Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference.

MATERIALS AND METHODS

Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained.

RESULTS

The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini.

CONCLUSIONS

The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT.