Qualitative and quantitative evaluation of bony structures based on DICOM dataset

Multislice computed tomography demonstrating mental nerve paresthesia caused by periapical infection: A case report

Components derived from an infected lesion within the bone can spread through various passages in the mandible, particularly via the mental foramen. Radiologically, the spread of infection is typically nonspecific and challenging to characterize; however, multislice computed tomography (MSCT) can effectively detect pathological changes in soft tissues and the bone marrow space. This report describes the case of a 55-year-old woman who experienced mental nerve paresthesia due to a periapical infection of the right mandibular second premolar. MSCT imaging revealed increased attenuation around the periapical lesion extending into the mandibular canal and loss of the juxtamental foraminal fat pad. Following endodontic treatment of the tooth suspected to be the source of the infection, the patient's symptoms resolved, and the previous MSCT imaging findings were no longer present. Increased bone marrow attenuation and obliteration of the fat plane in the buccal aspect of the mental foramen may serve as radiologic indicators of inflammation spreading from the bone marrow space.

Evaluation of the effect of long-term use of antidepressants in the SSRI group on bone density with dental volumetric tomography

Aim

The present study aims to employ dental volumetric tomography to examine bone mineral density among men that used antidepressants in the SSRI group for a long time.

Method

The present study was conducted through the utilisation of data related to patients that presented to the Faculty of Dentistry of Dicle University and had a dental volumetric tomography (DVT) scan for any reason. The patients were divided into 2 groups based on the use of antidepressants: Group 1 included 68 patients as the control group, and Group 2 consisted of 68 patients that used antidepressants. Radiomorphometric measurements were performed on DVT data: DVT-Mandibular Index (DVT-MI), DVT-Cortical Index (DVT-CI), Hounsfıeld Unit (HU) CORTICAL, and HU SPONGIOSIS values were calculated.

Results

The group of patients that used antidepressants exhibited a significant increase in DVT CI and a significant decrease in HU CORTICAL, HU SPONGIOSIS and DVT MI values. These findings were suggestive of osteoporosis.

Conclusion

Long-term use of antidepressants should be taken into consideration as a risk factor for osteoporosis in men.

CBCT-based bone quality assessment in decompression of large odontogenic cystic lesions

OBJECTIVES

Bone quality comprises bone mineral density and trabecular microstructure. The aim of this study was to explore the effectiveness of cone-beam computed tomography (CBCT) in evaluating bone quality of large odontogenic cystic lesions after decompression using CBCT and BoneJ software, and to determine whether secondary definitive surgery can be guided using CBCT data.

METHODS

Twenty-seven patients with large odontogenic cystic lesions treated by decompression were evaluated by CBCT. Medical history and perioperative details were analyzed.

RESULTS

The [Formula: see text]CT values for all patients with cystic lesions decreased after decompression, with no differences for age, sex, and histology (p > 0.05). Bone volume fraction and trabecular number of new cancellous bone (0.012%, 0.17/mm³) were lower than those of normal cancellous bone (0.189%, 0.47/mm³) (p < 0.05), while new cancellous bone trabecular separation (11.344 ± 2.556 mm) was stronger than normal cancellous bone trabecular separation (4.833 ± 2.232 mm) (p < 0.05). There were no differences in trabecular thickness between new cancellous bone (3.812 ± 1.593 mm) and normal cancellous bone (4.598 ± 3.573 mm) (p = 0.746). The [Formula: see text]CT values of five patients with favorable osteogenesis were - 72, -86, - 86, -47, and - 55, those of three patients with moderate osteogenesis were - 107, -120, and - 71, and those of two patients with poor osteogenesis were - 165 and - 127 during secondary definitive surgery.

CONCLUSIONS

CBCT is considered beneficial for evaluating bone quality of large odontogenic cystic lesions after decompression, while providing potentially useful information for referral to secondary definitive surgery.

Improving the Evaluation of Alveolar Bone Grafts with Cone Beam Computerized Tomography

Objective

Cone Beam computed tomography (CBCT) is used increasingly as a replacement for periapical x-rays when evaluating alveolar bone grafting. The manufacturer's standard settings for dental imaging may not, however, represent the optimal settings for evaluating postoperative alveolar bone grafts. We examined the influence of exposure parameters on CBCT image quality to optimize the quality of CBCT images while reducing the radiation dose to the minimum level necessary to obtain adequate images.

Methods

A defect was created in a cadaver head to simulate an alveolar cleft, and the area was filled with a synthetic material to simulate an alveolar bone graft. Serial CBCT scans were acquired, systematically varying tube voltage and tube current settings from 72 to 96kV and 3 to 12mA. Region of interest analysis was undertaken, and image quality was evaluated by comparing the ratios of native alveolar bone to soft tissue and the ratios of synthetic bone graft to soft tissue and by assessing image noise.

Results

Twenty-one CBCT data sets were obtained. Reducing tube voltage (kV) resulted in increased contrast ratio between bone and soft tissue and between synthetic bone graft and soft tissue, with maximal contrast at values of 76 kV/11 mA, 72 kV/12 mA, and 72 kV/11 mA. Of these, the setting with lowest image noise was 76 kV/11 mA. This setting also resulted in a radiation dose of less than half of the manufacturer's recommended settings for the same scan volume.

Conclusions

There is potential to improve CBCT image quality significantly while dramatically reducing the radiation dose during postoperative examinations for alveolar bone grafting in patients with cleft lip and palate.

Classification of periodontal biotypes with the use of CBCT. A cross-sectional study

OBJECTIVES

The aim of this study is to investigate the relationship between periodontal morphometric parameters and to develop a biotype classification based on the variables examined with the use of cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Forty-two periodontally healthy subjects that underwent a CBCT examination as part of a different diagnostic procedure participated in the study. Measurements were performed on sectional images and included gingival thickness and labial bone plate thickness midbuccally, crown width to crown length ratio, bone crest to the CEJ distance and bone crest to the gingival margin distance midbuccally, and at the approximal aspects of 186 maxillary anterior teeth.

RESULTS

Gingival thickness at the level of CEJ was positively correlated with labial bone plate thickness and crown form. Crown form was not correlated with labial bone plate thickness. Cluster analysis supported the existence of four periodontal biotypes, "thin," "thick," "average," and "mixed." Labial bone plate thickness was thinner than 1 mm at 70 % of the measured sites.

CONCLUSIONS

Only 50 % of the teeth belonged to thin or thick biotype. The other 50 % of the teeth belonged to the average cluster or presented mixed characteristics. Assessment of labial bone plate thickness based on periodontal biotype should be made with caution.

CLINICAL RELEVANCE

Taking into consideration the characteristics of periodontal biotypes enables the clinician to avoid complications in periodontology, prosthetic dentistry, implant dentistry in the esthetic zone, and orthodontics.

Decreased Bone Volume and Bone Mineral Density in the Tibial Trabecular Bone Is Associated with Per2 Gene by 405 nm Laser Stimulation

Low-level laser therapy/treatment (LLLT) using a minimally invasive laser needle system (MILNS) might enhance bone formation and suppress bone resorption. In this study, the use of 405 nm LLLT led to decreases in bone volume and bone mineral density (BMD) of tibial trabecular bone in wild-type (WT) and Per2 knockout (KO) mice. Bone volume and bone mineral density of tibial trabecular bone was decreased by 405 nm LLLT in Per2 KO compared to WT mice at two and four weeks. To determine the reduction in tibial bone, mRNA expressions of alkaline phosphatase (ALP) and Per2 were investigated at four weeks after 405 nm laser stimulation using MILNS. ALP gene expression was significantly reduced in the LLLT-stimulated right tibial bone of WT and Per2 KO mice compared to the non-irradiated left tibia (p < 0.001). Per2 mRNA expression in WT mice was significantly reduced in the LLLT-stimulated right tibial bone compared to the non-irradiated left tibia (p < 0.001). To identify the decrease in tibial bone mediated by the Per2 gene, levels of runt-related transcription factor 2 (Runx2) and ALP mRNAs were determined in non-irradiated WT and Per2 KO mice. These results demonstrated significant downregulation of Runx2 and ALP mRNA levels in Per2 KO mice (p < 0.001). Therefore, the reduction in tibial trabecular bone resulting from 405 nm LLLT using MILNS might be associated with Per2 gene expression.

Long-term effects of antihypertensive medications on bone mineral density in men older than 55 years

Introduction

In this study, we investigated the effects of long-term antihypertensive treatment with calcium channel blockers or beta blockers on the bone mineral density of maxilla, as determined by cone-beam computed tomography (CBCT).

Material and methods

This retrospective study was conducted on CBCT images of men older than 55 years who had received different dental indications. Data were grouped into three categories according to the antihypertensive medication history of the patients: group A included patients who had been taking beta-blocker treatment for more than 5 years, group B included patients who had been taking calcium channel blocker treatment for more than 5 years, and the control group included patients who had never used any hypertensive medications before.

Results

Statistically significant differences were observed between the beta blocker and calcium channel blocker groups.

Conclusion

In hypertension treatment, beta blockers may be preferred to calcium channel blockers in patients at high risk for osteoporosis and bone resorption.

Variability of dental cone beam CT grey values for density estimations

OBJECTIVE

The aim of this study was to investigate the use of dental cone beam CT (CBCT) grey values for density estimations by calculating the correlation with multislice CT (MSCT) values and the grey value error after recalibration.

METHODS

A polymethyl methacrylate (PMMA) phantom was developed containing inserts of different density: air, PMMA, hydroxyapatite (HA) 50 mg cm(-3), HA 100, HA 200 and aluminium. The phantom was scanned on 13 CBCT devices and 1 MSCT device. Correlation between CBCT grey values and CT numbers was calculated, and the average error of the CBCT values was estimated in the medium-density range after recalibration.

RESULTS

Pearson correlation coefficients ranged between 0.7014 and 0.9996 in the full-density range and between 0.5620 and 0.9991 in the medium-density range. The average error of CBCT voxel values in the medium-density range was between 35 and 1562.

CONCLUSION

Even though most CBCT devices showed a good overall correlation with CT numbers, large errors can be seen when using the grey values in a quantitative way. Although it could be possible to obtain pseudo-Hounsfield units from certain CBCTs, alternative methods of assessing bone tissue should be further investigated.

ADVANCES IN KNOWLEDGE

The suitability of dental CBCT for density estimations was assessed, involving a large number of devices and protocols. The possibility for grey value calibration was thoroughly investigated.

Miniscrew design and bone characteristics: an experimental study of primary stability

INTRODUCTION

The purpose of this study was to evaluate the correlations between bone characteristics, orthodontic miniscrew designs, and primary stability.

METHODS

Four different miniscrews were placed in pig ribs. The miniscrews were first scanned with a scanning electron microscope to obtain measurable images of their threads. Subsequently, the maximum insertion torque of the screws and the maximum load value in the pullout force tests were measured; furthermore, bone specimen characteristics were analyzed by using cone-beam computed tomography. For each bone sample, the insertion site cortical thickness as well as both cortical and marrow bone density were evaluated. The nonparametric Kendall rank correlation (tau) was used to evaluate the strength of the associations among the characteristics measured. The nonparametric Kruskall-Wallis test was used to evaluate the differences among the groups, and post-hoc comparisons were assessed by using the Nemenyi-Damico-Wolfe-Dunn test.

RESULTS

A significant dependence was found between pitch and maximum insertion torque (tau, -0.49). Positive correlations were also found between pullout force and maximum insertion torque (tau, 0.64), cortical thickness (tau, 0.36), and marrow bone density (tau, 0.35).

CONCLUSIONS

In this in-vitro experimental study, strong correlations were observed among miniscrew geometry, bone characteristics, and primary stability.

Incidence of maxillary sinusitis and oro-antral fistulae in bisphosphonate-related osteonecrosis of the jaw

OBJECTIVE

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious side-effect of bisphosphonate therapy. In the majority of cases BRONJ occurs in the mandible. As a consequence a detailed investigation of BRONJ of the maxilla and in particular of involvement of the maxillary sinus has largely so far been neglected. The aim of this study was to analyse the frequency of maxillary sinusitis and oro-antral fistulae in BRONJ of the maxilla.

SUBJECTS AND METHODS

A retrospective multicentre analysis was carried out in three Departments of Oral and Maxillofacial Surgery focussing on patients suffering from BRONJ in the maxilla. The role of involvement of the maxillary sinus, in particular sinusitis and oro-antral fistula, was analysed.

RESULTS

Out of a total of 170 patients suffering from BRONJ 53 cases (31.2%) with involvement of the maxilla were identified. At least one sign of maxillary sinusitis was present in 43.6% (23/53) and an oro-antral fistula in the course of the disease was detected in 35.8% (19/53) of those patients. The mean length of time of bisphosphonate intake was 36.16±16.32 months. Zoledronate was most frequently associated (60.4%) with symptoms, followed by the combination of Zoledronate/Ibandronate (13.2%), and Zoledronate/Pamidronate or Pamidronate alone (both 7.5%).

CONCLUSION

Maxillary sinusitis and oro-antral fistulae are associated with a BRONJ manifestation in the upper jaw in approximately 44%. The involvement of the maxillary sinus should be given special attention and three-dimensional imaging modalities might be necessary, not only to evaluate the extent of necrosis, but also to exclude involvement of the maxillary sinus.