Comparison of intraoperative CT- and cone beam CT-based spinal navigation for the treatment of atlantoaxial instability

BACKGROUND CONTEXT

Due to the complexity of neurovascular structures in the atlantoaxial region, spinal navigation for posterior C1-C2 instrumentation is nowadays a helpful tool to increase accuracy of surgery and safety of patients. Many available intraoperative navigation devices have proven their reliability in this part of the spine. Two main imaging techniques are used: intraoperative CT (iCT) and cone beam computed tomography (CBCT).

PURPOSE

Comparison of iCT- and CBCT-based technologies for navigated posterior instrumentation in C1-C2 instability.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

A total of 81 consecutive patients from July 2014 to April 2020.

OUTCOME MEASURES

Screw accuracy and operating time.

METHODS

Patients with C1-C2 instability received posterior instrumentation using C2 pedicle screws, C1 lateral mass or pedicle screws. All screws were inserted using intraoperative imaging either using iCT or CBCT systems and spinal navigation with autoregistration technology. Following navigated screw insertion, a second intraoperative scan was performed to assess the accuracy of screw placement. Accuracy was defined as the percentage of correctly placed screws or with minor cortical breach (<2 mm) as graded by an independent observer compared to misplaced screws.

RESULTS

A total of 81 patients with C1-C2 instability were retrospectively analyzed. Of these, 34 patients were operated with the use of iCT and 47 with CBCT. No significant demographic difference was found between groups. In the iCT group, 97.7% of the C1-C2 screws were correctly inserted; 2.3% showed a minor cortical breach (<2 mm); no misplacement (>2 mm). In the CBCT group, 98.9% of screws were correctly inserted; no minor pedicle breach; 1.1% showed misplacement >2 mm. Accuracy of screw placement demonstrated no significant difference between groups. Both technologies allowed sufficient identification of screw misplacement intraoperatively leading to two screw revisions in the iCT and three in the CBCT group. Median time of surgery was significantly shorter using CBCT technology (166.5 minutes [iCT] vs 122 minutes [CBCT]; p<.01).

CONCLUSIONS

Spinal navigation using either iCT- or CBCT-based systems with autoregistration allows safe and reliable screw placement and intraoperative assessment of screw positioning. Using the herein presented procedural protocols, CBCT systems allow shorter operating time.

Assessment of Nasal Septum Change after Le Fort I Osteotomy Using Cone Beam Computed Tomography

Objective

Le Fort I osteotomy (LF-IO) is widely used for the correction of dentofacial deformities, which may cause changes in the postoperative nasal septum (NS). The objective of this study was to evaluate the effects of LF-IO on the NS deviation and to determine whether the NS was affected by differences in the direction of maxilla movement.

Materials and Methods

A retrospective study including 57 patients who underwent LF-IO and received cone beam computed tomography (CBCT) preoperatively and 6-12 months postoperative evaluation was performed. The NS angle of each patient was measured both pre- and postoperatively in the two coronal sections (nasion and ostium levels). The patients were divided into five paired groups and calculated. Group 1 to 4 were divided depending on the differences in the direction of maxilla movement (Group 1. Impaction ≥ 5 mm vs. Impaction < 5 mm; Group 2. Anterior movement vs. Non-anterior movement; Group 3. Impaction symmetry vs. Impaction asymmetry; and Group 4. Impaction vs. Inferior repositioning). Group 5 was divided as One-piece osteotomy vs. Multi-segmental osteotomy.

Results

The mean NS angles at both nasion and ostium levels of all patients were significant increased after LF-IO. However, there were no statistical significant differences of the five paired groups.

Conclusions

LF-IO osteotomy influenced increasing of the NS deviation at both the nasion and ostium levels. However, differences in the direction of the maxilla movement and maxilla segmentation showed no statistically significant changes.

Assessment of gubernacular canal frequency with CBCT in a group of Turkish population

OBJECTIVE

The aim of this study is to investigate the frequency of the gubernacular canal observed on cone-beam computed tomography (CBCT) images in a group of Turkish populations according to age and gender.

MATERIALS AND METHODS

CBCT images of 500 cases were evaluated retrospectively, and a total of 117 impacted or erupting teeth were included in the study, and the presence of gubernacular canal was recorded according to age, gender and eruption status of the tooth. SPSS program was used for statistical analysis.

RESULTS

The mean age of 117 buried/continuing patients was 17 ± 15.32, 55 (47%) were female and were 62 (53%) male patients. Presence of gubernacular canal was observed in 91 (77.8%) cases and this duct was not detected in 26 (22.2%) cases. While 40.2% of female were found to have canals, 37.6% of male had canals. When the presence of canals was examined, the presence of canals was found to be significantly higher in the erupting teeth. A significant difference was found when analyzed according to the mean age.

CONCLUSIONS

CBCT is a useful method of detecting the gubernacular canal. The presence of gubernacular canal was significantly higher in erupting teeth.

Maxillary sinus in gender determination: a morphometric analysis using cone beam computed tomography

Gender determination of skeletal remains is an important forensic procedure in the identification process. Maxillary sinus remains intact even when the skull and other bones may be badly disfigured. Cone beam computed tomography (CBCT) can provide precise information about complex anatomical structures, as it is characterized by rapid volumetric image acquisition with high resolution. The present study aimed to assess the accuracy of maxillary sinus measurements using cone beam computed tomography in gender determination and to develop a formula using discriminate function analysis. Bilateral maxillary sinus images (left and right) were acquired for 200 patients (100 females and 100 males) and different parameters (width, length, height, area, perimeter, and volume) were measured and evaluated. Mean and standard deviation of both maxillary sinuses measurements were calculated and compared. The data was subjected to discriminative statistical analysis and analyzed using an unpaired t-test. The difference between all these variables was statistically significant between males and females. Based on discriminant analysis, the most pronounced variable in the differentiation of gender groups was maxillary sinus height. Gender assessment was established correctly with an accuracy of 75% for females and 64% for males with an overall accuracy of 69.5%. Adding other independent variables to the model did not result in an improvement in overall accuracy. Cone beam computed tomography measurement of maxillary sinus can be used as an aid in forensic anthropology for gender determination.

Reliability and accuracy of a semi-automatic segmentation protocol of the nasal cavity using cone beam computed tomography in patients with sleep apnea

OBJECTIVES

The objectives of this study included using the cone beam computed tomography (CBCT) technology to assess: (1) intra- and inter-observer reliability of the volume measurement of the nasal cavity; (2) the accuracy of the segmentation protocol for evaluation of the nasal cavity.

MATERIALS AND METHODS

This study used test-retest reliability and accuracy methods within two different population sample groups, from Eastern Asia and North America. Thirty obstructive sleep apnea (OSA) patients were randomly selected from administrative and research oral health data archived at two dental faculties in China and Canada. To assess the reliability of the protocol, two observers performed nasal cavity volume measurement twice with a 10-day interval, using Amira software (v4.1, Visage Imaging Inc., Carlsbad, CA). The accuracy study used a computerized tomography (CT) scan of an OSA patient, who was not included in the study sample, to fabricate an anthropomorphic phantom of the nasal cavity volume with known dimensions (18.9 ml, gold standard). This phantom was scanned using one NewTom 5G (QR systems, Verona, Italy) CBCT scanner. The nasal cavity was segmented based on CBCT images and converted into standard tessellation language (STL) models. The volume of the nasal cavity was measured on the acquired STL models (18.99 ± 0.066 ml).

RESULTS

The intra-observer and inter-observer intraclass correlation coefficients for the volume measurement of the nasal cavity were 0.980-0.997 and 0.948-0.992 consecutively. The nasal cavity volume measurement was overestimated by 1.1%-3.1%, compared to the gold standard.

CONCLUSIONS

The semi-automatic segmentation protocol of the nasal cavity in patients with sleep apnea and by using cone beam computed tomography is reliable and accurate.

CLINICAL RELEVANCE

This study provides a reliable and accurate protocol for segmentation of nasal cavity, which will facilitate the clinician to analyze the images within nasoethmoidal region.

Deep learning for detection and 3D segmentation of maxillofacial bone lesions in cone beam CT

OBJECTIVES

To develop an automated deep-learning algorithm for detection and 3D segmentation of incidental bone lesions in maxillofacial CBCT scans.

METHODS

The dataset included 82 cone beam CT (CBCT) scans, 41 with histologically confirmed benign bone lesions (BL) and 41 control scans (without lesions), obtained using three CBCT devices with diverse imaging protocols. Lesions were marked in all axial slices by experienced maxillofacial radiologists. All cases were divided into sub-datasets: training (20,214 axial images), validation (4530 axial images), and testing (6795 axial images). A Mask-RCNN algorithm segmented the bone lesions in each axial slice. Analysis of sequential slices was used for improving the Mask-RCNN performance and classifying each CBCT scan as containing bone lesions or not. Finally, the algorithm generated 3D segmentations of the lesions and calculated their volumes.

RESULTS

The algorithm correctly classified all CBCT cases as containing bone lesions or not, with an accuracy of 100%. The algorithm detected the bone lesion in axial images with high sensitivity (95.9%) and high precision (98.9%) with an average dice coefficient of 83.5%.

CONCLUSIONS

The developed algorithm detected and segmented bone lesions in CBCT scans with high accuracy and may serve as a computerized tool for detecting incidental bone lesions in CBCT imaging.

CLINICAL RELEVANCE

Our novel deep-learning algorithm detects incidental hypodense bone lesions in cone beam CT scans, using various imaging devices and protocols. This algorithm may reduce patients' morbidity and mortality, particularly since currently, cone beam CT interpretation is not always preformed.

KEY POINTS

• A deep learning algorithm was developed for automatic detection and 3D segmentation of various maxillofacial bone lesions in CBCT scans, irrespective of the CBCT device or the scanning protocol. • The developed algorithm can detect incidental jaw lesions with high accuracy, generates a 3D segmentation of the lesion, and calculates the lesion volume.

Prevalence and characteristics of accessory mandibular canals in an eastern Chinese population by cone beam computed tomography

PURPOSE

This retrospective study aimed to determine the prevalence and morphological characteristics of accessory mandibular canals (AMCs) in an eastern Chinese population to provide clinical guidance for reducing intraoperative and postoperative complications.

METHODS

Cone beam computed tomography (CBCT) scans of 300 Chinese patients were used to identify AMCs according to a modification of Naitoh's classification. The length of the branch (L0) and the upper and lower angles between the branch and mandibular canal were measured on sagittal images. Additionally, the branches were divided into narrow or wide types by calculating the ratio of the branch diameter to the main canal diameter. The location of the bifurcation point was characterized by measuring its distance to the buccal wall of the mandible (L1), lingual wall of the mandible (L2) and alveolar ridge (L3).

RESULTS

The prevalence rate of AMCs was 40.7% (95% CI: 35.1-46.3), and the most common type was the retromolar canal, followed by the forward canal, dental canal, trifid mandibular canals (TMCs) or others, inferior canal and buccolingual canal. Twenty-one cases of multiple branches with unusual patterns were observed in the study. The average values of L0, L1, L2 and L3 were 15.05 ± 0.63 mm, 5.79 ± 0.14 mm, 4.40 ± 0.18 mm and 14.61 ± 0.31 mm, respectively. The mean upper angle and lower angle were 141.59° ± 2.44° and 50.64° ± 2.57°, respectively. Approximately 20.8% of the branches were defined as wide type, and no statistical significance was found between different types.

CONCLUSION

AMCs are not rare anatomic variations of the mandibular canal in the eastern Chinese population; thus, CBCT examination is highly recommended for precise evaluation before surgeries involving the mandibles.

Evaluation of sex dimorphism of the mandible with geometric morphometric analysis: conventional and reconstructed panoramic radiography study

PURPOSE

The purpose of the study was to investigate the mandible shape dimorphism between males and females both on conventional panoramic radiographs (cPR) and reconstructed panoramic radiographs obtained from cone beam computed tomography (rPR) with geometric morphometric method.

METHODS

Panoramic radiographs and cone beam computed tomography scans were performed on 33 males and 35 females with median age 23.0 (13.0-57.0) years old. The mandibular shape comparisons between genders were examined with Procrustes analysis, mandible shape classification analysis was made with principal component analysis and shape deformations were concluded from thin plate spline (TPS) analysis.

RESULTS

Age had no statistically significant difference between gender (p = 0.580). For the shape of mandible on cPR and rPR, there were statistically significant differences between males and females (p = 0.002, p = 0.032, respectively). The shape variabilities of mandible on cPR for females were 0.054 and for males 0.053. The shape variabilities of mandible on rPR for females were 0.051 and for males 0.049. Both on cPR and rPR, the shape variability of the females' mandible was similar within their group, the shape variability of the males' mandible was similar within their group. In the examination of mandibular dimorphism in cPR, maximal deformations were seen in the region between the mandibular notch, posterior ramus, anterior ramus, gonion, in both sides, in TPS graphs. On the other hand, a high level of deformations was observed in all landmarks that define the mandibular shape on rPR.

CONCLUSIONS

The mandible dimorphism can be detected in the examination performed with geometric morphometric methods on cPR and rPR. While mandible shape differences according to gender are seen most in the ramus region in cPR, differences can be detected in all landmarks in rRP.

Comparison of different methods of analysis of maxillary sinus volume and validation of a new proposal using cone beam computed tomography

PURPOSE

develop and validate a formula, through a discriminant analysis of sex estimation, evaluating maxillary sinus in cone beam computed tomography scans in a Brazilian population, comparing this formula with two other existing ones.

METHODS

190 cone beam CT scans of Brazilian adults were retrospectively evaluated by an independent examiner. Measurements were performed in the right and left MS region: height, width, length, distance between the breasts, distance between infraorbital foramina, and volume in the ITK software. The sample was divided into female and male. T test, ANOVA, Tukey test and the ROC Curve was performed (p > 0,05).

RESULTS

statistically significant differences were found in relation to the maximum height of the MS both right (p = 0,001) and left (p = 0,026) between sexes and the maximum length in the right MS (p = 0,01). Regarding the comparison of MS volume according to the different analysis methods, statistically significant differences were found between sexes for the right MS when using the method by Bangi et al. (p = 0,012) and the volume of the left MS in females (p < 0,001). Comparing the three classification models, statistically significant differences were found between the proposed method and the classification by Bangi et al. (p < 0.007). The ROC curve showed greater accuracy in the classification proposed in this work.

CONCLUSION

the new proposed formula obtained better predictions of sexual dimorphism, when compared to classifications already described in the literature.

CBCT imaging and root canal treatment for taurodontism in mandibular second molar - A case report and literature review

The mandibular second molar exhibits a wide range of intricate root canal variations, which can present challenges and difficulties in achieving successful root canal treatment. This report focuses on two specific cases involving a root canal variation in a typical taurodontism of the mandibular second molar. To provide a comprehensive analysis and illustration of the anatomical structure of intraoral taurodontism and the important considerations for root canal treatment, we utilized advanced imaging techniques such as cone beam computed tomography (CBCT) and a dental microscope. By combining these tools, we were able to gain a deeper understanding of the complex root canal system and make informed decisions during the treatment process.

Effects of rhBMP-2 with various carriers on maxillofacial bone regeneration through computed tomography evaluation

BACKGROUND

rhBMP-2 is regarded as the most potent osteoinductive growth factor, and it has been used in the oral cavity with different carriers. The purpose of this study is to evaluate the bone-regenerative effect of rhBMP-2 delivered with different carrier systems through three-dimensional cone beam computed tomography analysis.

METHOD

A total of 112 patients underwent oral surgery with rhBMP-2 application (Group 1, n = 53) or without rhBMP-2 application (Group 2, n = 59). Group 1 was divided into 3 groups according to carriers, rhBMP-2 with allograft (Group 1-1, n = 34), rhBMP-2 with xenograft (Group 1-2, n = 5), and rhBMP-2 with absorbable collagen sponge (Group 1-3, n = 14). Cone beam computed tomography scans were taken before surgery (T0) 6 months after surgery (T1). The volume of defects was measured through the three-dimensional image analysis tool.

RESULTS

The average bone regeneration rate of Group 1 was significantly greater than that of Group 2. Within Group 1, the group that used allograft as a carrier (Group 1-1) showed significantly higher bone regeneration rates than the group that used absorbable collagen sponge as a carrier (Group 1-3).

CONCLUSION

The use of rhBMP-2 after oral surgery results in a superior bone regeneration rate compared to not using rhBMP-2, and its efficacy depends on the carriers it is used with. Allograft affects bone regeneration more than absorbable collagen sponge when it is carried with rhBMP-2. Therefore, the appropriate use of rhBMP-2 with suitable bone grafting materials is useful for promoting postoperative bone regeneration in oral surgery.

An unsupervised dual contrastive learning framework for scatter correction in cone-beam CT image

PURPOSE

Cone-beam computed tomography (CBCT) is widely utilized in modern radiotherapy; however, CBCT images exhibit increased scatter artifacts compared to planning CT (pCT), compromising image quality and limiting further applications. Scatter correction is thus crucial for improving CBCT image quality.

METHODS

In this study, we proposed an unsupervised contrastive learning method for CBCT scatter correction. Initially, we transformed low-quality CBCT into high-quality synthetic pCT (spCT) and generated forward projections of CBCT and spCT. By computing the difference between these projections, we obtained a residual image containing image details and scatter artifacts. Image details primarily comprise high-frequency signals, while scatter artifacts consist mainly of low-frequency signals. We extracted the scatter projection signal by applying a low-pass filter to remove image details. The corrected CBCT (cCBCT) projection signal was obtained by subtracting the scatter artifacts projection signal from the original CBCT projection. Finally, we employed the FDK reconstruction algorithm to generate the cCBCT image.

RESULTS

To evaluate cCBCT image quality, we aligned the CBCT and pCT of six patients. In comparison to CBCT, cCBCT maintains anatomical consistency and significantly enhances CT number, spatial homogeneity, and artifact suppression. The mean absolute error (MAE) of the test data decreased from 88.0623 ± 26.6700 HU to 17.5086 ± 3.1785 HU. The MAE of fat regions of interest (ROIs) declined from 370.2980 ± 64.9730 HU to 8.5149 ± 1.8265 HU, and the error between their maximum and minimum CT numbers decreased from 572.7528 HU to 132.4648 HU. The MAE of muscle ROIs reduced from 354.7689 ± 25.0139 HU to 16.4475 ± 3.6812 HU. We also compared our proposed method with several conventional unsupervised synthetic image generation techniques, demonstrating superior performance.

CONCLUSIONS

Our approach effectively enhances CBCT image quality and shows promising potential for future clinical adoption.

Furcation area and root proximity of molars as a risk indicator of periodontitis: a cone‑beam computed tomography-based study

OBJECTIVES

This study assessed the root proximity in molars and the furcation area (FA) in the first root separation point (RSP) using cone‑beam computed tomography (CBCT) and evaluated the association between the furcation area of molars and periodontal status of the patients.

METHODS

A total of 264 molar teeth in 66 participants were included in the study. The control group consisted of 110 molar teeth of participants, and 154 molar teeth were included in periodontitis group, which consisted of only stage II and III periodontitis patients. FA, RSP, and root proximities were measured in axial slices, and bone resorption rates were measured in sagittal slices.

RESULTS

Both maxillary and mandibular molar groups had significantly less FA in periodontitis group than in controls (p < 0.005), and there were significant relationships between the degree of bone resorption in molars and FA and furcation grades (p < 0.001). According to regression analysis, the risk of periodontitis increased by 1.011 times as total FA decreased (p < 0.001), and periodontitis risk of maxillary molar was 1.693 times higher than mandibular molars but not found to be statistically significant (p = 0.152). When assessing the root proximity between molar teeth, maxillary molars showed significantly higher root proximity in CEJs than mandibular molars in both periodontitis and control groups (p < 0.05).

CONCLUSIONS

The results indicate that the association between FA and the degree of bone resorption and root proximity of maxillary molars might be considered as a risk indicator for bone resorption in molars and might play a role during disease progression.

Assessment of the diagnostic accuracy of strip and furcal perforations in different sizes by cone beam computed tomography

OBJECTIVE

Root perforation is an adverse event that may accidentally occur during root canal treatment and can adversely affect the treatment plan and tooth prognosis. This study aimed to assess the accuracy of cone beam computed tomography (CBCT) for detecting the strip and furcal perforations with different sizes.

METHODS

The mesiolingual canals of 155 extracted human mandibular first molars were instrumented and randomly divided into four experimental groups and one control group (n = 31). Furcal (in the pulp chamber floor) and strip perforations with 0.5, 1, 1.5, and 2 mm in diameter were manually created. The teeth were randomly mounted in bovine ribs and scanned using CBCT. Two radiologists unaware of the study groups observed the images and reported the greatest perforation diameter. The inter-observer agreements were calculated. The diagnostic accuracy was compared for furcal and strip perforations with different sizes.

RESULTS

The inter-observer agreement for detecting furcal and strip perforations with different sizes were good. The diagnostic accuracy was 100% for the absence of perforation in each group.

CONCLUSIONS

CBCT can detect the absence of perforation with high accuracy. The diagnostic accuracy of CBCT in the presence of strip and furcal perforation with different sizes was not significant.

Evaluation of maxillary palatal process pneumatization by cone-beam computed tomography

PURPOSE

The aim of this study is to investigate the pneumatization type of the palatal process (PTP) and angular and distance measurements of neighbouring structures on cone beam computed tomography (CBCT) images.

MATERIALS AND METHODS

400 maxillary sinuses (MS) of 200 patients (96 female; 104 male; mean age: 43.2) were retrospectively evaluated. PTP was divided into three as types 1,2 and 3 and evaluated at distances 4, 8, 16, and 24 mm posterior to incisive foramen. The sinus and alveolar ridge height, palatonasal recess angle (PRA) and palatal junction angle (PJA) were also measured and recorded.

RESULTS

PTP I (101, 25.3%) was the most frequent type, followed by PTP II (95, 23.8%), and the least was PTP III (4, 1%). In patients with PTP I, the alveolar ridge height in the 4 mm and 8 mm group was significantly higher than in the patients with PTP II and III (p<0.05). In patients with PTP I, PRA in the 4 mm and 16 mm groups was significantly higher than in patients with PTP II and III (p<0.05). Sinus and alveolar ridge height, PRA and PJA did not differ significantly between the right and left sides in the 4 mm, 8 mm, 16 mm, and 24 mm groups (p>0.05).

CONCLUSION

Knowing the anatomy of the MS is very important for a successful surgical procedure in this area. Anatomy and pathology of the MS can be understood more clearly in CBCT.

Dimensional and positional temporomandibular joint osseous characteristics in normodivergent facial patterns with and without temporomandibular disorders

OBJECTIVE

This study evaluated the dimensional and positional osseous temporomandibular joint features in normodivergent facial patterns with and without temporomandibular disorders.

METHODS

A total of 165 adult patients were divided into two groups: group 1 (n = 79 patients; 158 joints): temporomandibular disorders patients and group 2 (n = 86 patients; 172 joints): non-temporomandibular disorders patients. Three-dimensional positional and dimensional temporomandibular joint characteristics, including glenoid fossa, mandibular condyles, and joint spaces, were assessed by cone beam computed tomography.

RESULTS

The glenoid fossa positions in the three orthogonal planes and height showed statistical significance between the two studied groups. The temporomandibular disorders patients showed higher horizontal and vertical condyle inclinations while anteroposterior inclination was less, and the condyle was positioned more superior, anterior, and lateral in the glenoid fossa. The condyle width and length showed no significance between the two groups, while condyle height was smaller in temporomandibular disorders patients. Anterior and medial joint spaces increased while the superior and posterior joint spaces reduced in temporomandibular disorders patients.

CONCLUSION

There were significant differences between the patients with and without temporomandibular joint disorders in terms of mandibular fossa positions and height as well as condylar positions and inclinations in horizontal and vertical planes together with reduced condylar height and reduced posterior and superior joint spaces in the temporomandibular disorders patients.

CLINICAL RELEVANCE

The temporomandibular disorder is a multifactorial disorder in which one of these factors is the dimensional and positional characteristics of the temporomandibular joints; including or excluding this factor requires a comprehensive three-dimensional investigation of patients with TMD compared to the normal group under the condition that the facial pattern is average as a confounding factor.

Evaluation of the morphology of accessory canals of the canalis sinuosus via cone-beam computed tomography

PURPOSE

This study aims to assess the presence of accessory canal (AC) associated with canalis sinuous (CS), describing their frequency, lateralization, location, direction, and measurements in cone beam computed tomography (CBCT).

METHODS

Axial, coronal, sagittal, and cross-sectional reconstructions were analyzed in 248 CBCT images and the presence of CS, the presence of AC associated with CS, the lateralization, localization, and direction course of AC associated with CS was evaluated. CS diameter, AC diameter, the distance between the nasal cavity floor and CS (M1), CS and the buccal cortical bone (M2), and CS and the alveolar ridge (M3) were measured.

RESULTS

CS was detected in all CBCT scans as bilaterally. The prevalence of AC associated with CS was 35.5%. There was a significant difference between dental status anthe d presence of AC associated with CS. There was a significant difference between gender, dental status, and lateralization of AC associated with CS. While M1 was greater in male patients than females, M3 was greater in female patients. M2 and M3 were greater in younger patients.

CONCLUSION

Clinicians performing surgical procedures should keep in mind that anatomical variations of the vascular nerve bundle may be seen. M1, M2, and M3 measurements can be affected by gender, age, and dental status.

Effects of mandibular advancement devices on upper airway dimensions in obstructive sleep apnea: responders versus non-responders

STUDY OBJECTIVES

To compare the effects of mandibular advancement device (MAD) therapy on upper airway dimensions between responders and non-responders with mild to moderate obstructive sleep apnea (OSA).

METHODS

Thirty-one participants (21 men and 10 women) with a mean ± SD apnea-hypopnea index (AHI) of 16.6 ± 6.7 events/h, and aged 48.5 ± 13.9 years, were included in this study. Polysomnographic recordings and cone beam computed tomography (CBCT) scans in supine position were performed for every participant at baseline and at 3-month follow-up with their MAD in situ. Responders were defined as having ≥ 50% reduction in baseline AHI with a residual AHI < 10 events/h. The primary outcome variable was the minimal cross-sectional area of the upper airway (CSAmin).

RESULTS

No significant differences were found between responders (n = 15) and non-responders (n = 16) in age, gender distribution, body mass index, and neck circumference (P = 0.06-0.93), nor in AHI and CSAmin (P = 0.40 and 0.65, respectively) at baseline. The changes of the CSAmin with MAD in situ in the responder group were not significantly different compared to those in the non-responder group (P = 0.06).

CONCLUSION

Within the limitations of this study, we conclude that the changes of the upper airway dimensions induced by MADs are not significantly different between responders and non-responders with mild to moderate OSA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865.

Comparison of the skeletal, dentoalveolar, and periodontal changes after Ni-Ti leaf spring expander and rapid maxillary expansion: a three-dimensional CBCT based evaluation

BACKGROUND

The aim of the present study was twofold:(1) three-dimensionally evaluate the quantitative skeletal and dentoalveolar changes after Ni-Ti leaf spring expander (leaf expander) and rapid maxillary expansion (RME) in mixed dentition patients;(2) analyze the modifications of the buccal alveolar bone plate of the maxillary first permanent molars.

METHODS

Patients who underwent CBCT scans before and after maxillary expansion were randomly selected from the records archived at the Department of Biomedical Surgical and Dental Sciences, University of Milan, Italy. Inclusion criteria were the following: no systemic disease or syndromes; maxillary transverse deficiencies (difference between the upper intermolar width and the lower intermolar width of at least 3 mm and/or clinical need based on radiographic evaluation), early mixed dentition with ages between 7 to 10 years old; cervical vertebra maturation stage (CVMS) 1 or 2; no pathologic periodontal status; skeletal class I or II; maxillary expander cemented on the upper second deciduous molars. Exclusion criteria were the following: patients with pubertal or post-pubertal stage of development (CVMS 3-6); late deciduous or late mixed dentition, impossibility to use the second primary molar as anchorage; skeletal class III malocclusion; craniofacial syndromes; patients unable to be followed during the treatment period. Twenty-three patients treated with Leaf Expander, 11 males (mean age 7.8 ± 0.6 years) and 12 females (mean age 8.1 ± 0.8 years), met the inclusion criteria and constituted the case group. Twenty-four (control group) treated with conventional RME, 12 males (mean age 8.4 ± 0.9 years) and 12 females (mean age 8.1 ± 0.7 years). The paired-sample T test was used for intra-group comparison to evaluate the difference between before (T1) and after (T2) maxillary expansion. Independent sample t-test was computed to perform between groups comparison of the skeletal, dentoalveolar, and periodontal changes.

RESULTS

The Leaf Expander and RME group showed a significant increase between T1 and T2 for most of the skeletal and dentoalveolar variables. Concerning the skeletal variables only the RME demonstrated a significant increase at the level of the posterior nasal (PNW) and apical base width (PABW) and maxillary mid-alveolar width (MMW). Despite this, when compare with the Leaf Expander, the RME group exhibited a statistically larger width increase for only two skeletal parameters: PNW (p = 0.03) and MMW (p = 0.02). No significant changes at the periodontal level were found in either group.

CONCLUSIONS

According to the current research, the authors confirm the effectiveness of the Leaf Expander and RME to produce similar skeletal and dentoalveolar effects in mixed dentition subjects. Moreover, the devices anchored to deciduous teeth did not reduce the thickness and height of the buccal bone at the level of the maxillary permanent first molars in either of the two groups.

Intraoperative CBCT imaging in endovascular abdomen aneurysm repair - Optimization of exposure parameters using a stent phantom

Cone beam computed tomography (CBCT) may provide essential additional image guidance to endovascular abdominal aneurysm repair (EVAR) operations but also significant radiation exposure to patients if scans are not carefully optimized. The purpose of our study was to define the image quality requirements for intraoperative EVAR CBCT imaging and to optimize the CBCT exposure parameters accordingly. A Multi-Energy CT phantom simulating a large patient was used by replacing the central phantom cylinder with a custom water-filled insert including an EVAR stent. Different exposure parameters covering a range of radiation qualities and dose levels were used to define the optimal image quality level regarding stent graft evaluation (compressed, bent, or collapsed). The radiation dose was measured with a calibrated air kerma-area product (KAP) meter and organ doses were calculated based on Monte Carlo simulations and a mathematical patient model. Based on the results, updated exposure parameters with the highest mean energy and lowest dose level available were recommended. With the updated protocol, the radiation exposure could be significantly decreased. The KAP value decreased from 9720 μGy·m2 to 440 μGy·m2 and reference point air kerma from 351 mGy to 16 mGy (a reduction of 96%) and organ doses of the organs in the irradiated region decreased on an average 91%. The new protocol resulted in acceptable clinical image quality based on testing with clinical cases.

Radiographic patterns of periosteal bone reactions associated with endodontic lesions

Objectives

The formation of new bone by periosteum due to an insult is called periosteal bone reaction (PBR). This study assessed the cone beam computed tomography (CBCT) patterns of periosteal bone reactions associated with periapical inflammatory lesion (apical periodontitis/periapical rarefying osteitis).

Materials and Methods

Twenty-two small field of view CBCT images of patients with PBR were selected from a database of a private practice limited to endodontics. The volume of the periapical inflammatory lesion, the presence of cortical fenestration, the distance of the root apices to the affected cortex, and the location, pattern, and longest diameter of the periosteal reaction were recorded. Statistical analysis was performed using Wilcoxon Ranksum, Fischer's exact, Spearman Correlation Coefficient, and paired t-test.

Results

In all cases, periosteal bone reaction manifested as either parallel (90.9%) or irregular (9.1%). No correlation was found between periapical inflammatory lesion volume and the periosteal reaction's longest diameter (p > 0.05). Cortical fenestration was noted in 72.7% of the cases. In addition, the findings showed that periosteal reactions were located mostly on the buccal and were present 53.8% and 100% of the time in the mandible and maxilla, respectively.

Conclusions

The periosteal reactions of endodontic origin had a nonaggressive form (i.e., parallel or irregular), and none of the lesions resulted in a periosteal reaction with an ominous Codman's triangle or spicule pattern.

Radiologic findings of osteonecrosis, osteoradionecrosis, osteomyelitis and jaw metastatic disease with cone beam CT

PURPOSE

The purpose of this study was to assess CBCT scans of patients with medication related osteonecrosis of the jaws (MRONJ), osteoradionecrosis (ORN), osteomyelitis (OM) and jaw metastatic disease (JM), evaluate the presence and extent of radiologic findings, identify radiologic parameters that may distinguish the four entities and last, introduce a new modified radiographic index (CRIm), in order to contribute to the diagnosis of these conditions.

METHODS

Τwo major databases were retrospectively searched for fully documented and diagnosed CBCT scans of MRONJ, ORN, OM and JM from 2006 to 2019. 335 CBCT scans met the inclusion criteria and were assessed under standardized viewing conditions blindly by 2 observers. The CRIm index proposed in this study evaluates: lytic changes, sclerosis, periosteal bone formation, sequestration, non-healing extraction sockets and other findings which included: sinus implication, inferior alveolar canal implication and jaw fracture. Lytic changes, sclerosis, periosteal bone formation, sequestration and non-healing extraction sockets were scored as: absent (0), localized/single (1) and extensive/multiple (2). Each one of other findings were scored individually as: absent (0) and present (1). For statistical analysis t-test, Pearson's r correlation coefficient, one-way ANOVA and Bonferonni were performed.

RESULTS

Extensive lytic changes were the most common finding, especially for ORN, where it occurred in all CBCT scans (100%). The mean value of the CRIm index differs significantly between CBCT scans with MRONJ and JM, as well as between those with OM and JM (Bonferroni p < 0.001).

CONCLUSIONS

The new modified Composite Radiographic Index introduced in this study, appears to have improved an objective approach to the previously used Composite Radiographic Index by means of cumulative radiologic features. Τhe predominance of certain radiologic features in one or more of these entities may lead the diagnostician towards the correct diagnosis.