The current status of cone beam computed tomography imaging in orthodontics

AAPM Task Group Report 261: Comprehensive quality control methodology and management of dental and maxillofacial cone beam computed tomography (CBCT) systems

Cone-beam computed tomography (CBCT) systems specifically designed and manufactured for dental, maxillofacial imaging (MFI) and otolaryngology (OLR) applications have been commercially available in the United States since 2001 and have been in widespread clinical use since. Until recently, there has been a lack of professional guidance available for medical physicists about how to assess and evaluate the performance of these systems and about the establishment and management of quality control (QC) programs. The owners and users of dental CBCT systems may have only a rudimentary understanding of this technology, including how it differs from conventional multidetector CT (MDCT) in terms of acceptable radiation safety practices. Dental CBCT systems differ from MDCT in several ways and these differences are described. This report provides guidance to medical physicists and serves as a basis for stakeholders to make informed decisions regarding how to manage and develop a QC program for dental CBCT systems. It is important that a medical physicist with experience in dental CBCT serves as a resource on this technology and the associated radiation protection best practices. The medical physicist should be involved at the pre-installation stage to ensure that a CBCT room configuration allows for a safe and efficient workflow and that structural shielding, if needed, is designed into the architectural plans. Acceptance testing of new installations should include assessment of mechanical alignment of patient positioning lasers and x-ray beam collimation and benchmarking of essential image quality performance parameters such as image uniformity, noise, contrast-to-noise ratio (CNR), spatial resolution, and artifacts. Several approaches for quantifying radiation output from these systems are described, including simply measuring the incident air-kerma (Kair) at the entrance surface of the image receptor. These measurements are to be repeated at least annually as part of routine QC by the medical physicist. QC programs for dental CBCT, at least in the United States, are often driven by state regulations, accreditation program requirements, or manufacturer recommendations.

Alveolar bone morphology in patients with palatally-displaced maxillary lateral incisors before and after orthodontic treatment: A cone-beam computed tomography study

INTRODUCTION

Palatal displacement of maxillary anterior teeth is common in clinical practice. Previous studies have reported that the labial bone around palatally-displaced incisors is thinner than that around normally-placed teeth. Therefore, it is necessary to elucidate alveolar bone changes after alignment to guide orthodontic treatment. In this study, we investigated the alveolar bone changes around palatally-displaced maxillary lateral incisors before and after treatment, and the effects of extraction and age using cone-beam computed tomography.

METHODS

In this retrospective study, 55 patients with unilateral palatally-displaced maxillary lateral incisors were included. Three-dimensional alveolar bone changes were measured at three levels (25%, 50% and 75% of the root length) using cone-beam computed tomography. Group comparisons were made between displaced and control teeth, extraction and non-extraction groups, and adult and minor groups.

RESULTS

After orthodontic treatment, labiopalatal and palatal alveolar bone widths decreased at all measured levels. Labial alveolar bone width increased significantly at P25, but decreased at P75. Concavity decreased, while tooth-axis angle, tooth length, B-CEJ and P-CEJ increased. Changes in LB and LP at P75, B-CEJ and P-CEJ were statistically significant. After treatment, the tooth-axis angle on the PD side increased by 9.46°. The change in tooth-axis angle on the PD side was significantly smaller, and LB and LP decreased more at P75, in the extraction group.

CONCLUSIONS

Compared to the control teeth, alveolar bone thickness and height for the displaced teeth decreased more significantly after treatment. Tooth extraction and age also influenced alveolar bone changes.

Development of occlusal canting identifying tool: verification, reliability and validation assessment

INTRODUCTION

Occlusal cant (OC) is a malocclusion trait that lacks accurate clinical assessment methods. The occlusal canting identifying tool (OCIT) was invented and patented as a clinical tool to accurately identify and quantify the degree of maxillary OC. This study aimed to 1) develop a prototype of the OCIT, 2) verify the functionality of the OCIT and 3) assess the validity and reliability of the OCIT.

MATERIALS AND METHODS

A patented OCIT design was revised, and the dimensions were finalized, followed by a three-dimensional conceptual prototype design that was reviewed and approved by the inventors. Verification was performed using a digital angle gauge to determine the accuracy of the bubble level as well as the angle between the bite plate and the protractor. For laboratory validation, 40 orthodontists measured the simulated OC at (0°, 2°, 4°, 6° and 8°) on five phantom heads using the OCIT. A reliability assessment of the tool was performed in three occasions by one orthodontist using the same laboratory settings.

RESULTS

The OCIT was prototyped from a medical-grade stainless steel alloy (316 L). Verification assessment revealed that the accuracy error of the bubble level (0.316° ± 0.028°) was statistically significant but clinically insignificant, while that of the angle between the bite plate and protractor (0.100° ± 0.050°) was statistically insignificant. Validation assessment showed high validity of the OCIT with no statistically significant difference between the OCIT and the reference values, having more errors in identifying smaller OC degrees compared to larger OC degrees. The intraclass correlation coefficient indicated the high reliability of the OCIT.

CONCLUSION

The OCIT was verified and proven to be a valid and reliable clinical tool that accurately evaluates the degree of OC.

Indications and use of cone beam computed tomography in children and young individuals in a university-based dental hospital

BACKGROUND

The aim of this study was to evaluate the indications of cone beam computed tomography (CBCT) in children and young individuals in a university-based dental hospital and their association with age, gender and field of view.

METHODS

7131 CBCT scans, taken during 3-year period, were reviewed and a total of 649 pediatric patients (0-18 years) with complete request forms were included. Data related to gender, age, referring department, CBCT indications, field of view (FOV), region of interest (ROI), need for re-exposure and patients received more than one CBCT examination were recorded.

RESULTS

The mean age was 13.57 ± 3.52 years and "malocclusion and dentofacial anomaly" (28.7%) was the most common clinical indication. Facial trauma, dental trauma and supernumerary tooth in males; "malocclusion and dentofacial anomaly" and implant planning in females were recorded more frequently compared to other gender. Maxilla was the most frequently monitored ROI (35.1%) for patients. Small (≤ 10 cm) FOV was preferred in 58.1% of all patients. Large FOV was selected in the majority of patients who underwent CBCT scan for "malocclusion and dentofacial anomaly" (89.6%). The repeated scans constituted 2.3% of patients and 105 patients (16.2%) underwent multiple CBCT scans on different dates for mainly orthodontic follow-up.

CONCLUSIONS

The justification of CBCT scans was not fully compatible with current guidelines and mainly larger FOV was preferred. The number of CBCT examination in children and young individuals tends to increase.

TRIAL REGISTRATION NUMBER

Not applicable.

Connecting the dots towards precision orthodontics

Precision orthodontics entails the use of personalized clinical, biological, social and environmental knowledge of each patient for deep individualized clinical phenotyping and diagnosis combined with the delivery of care using advanced customized devices, technologies and biologics. From its historical origins as a mechanotherapy and materials driven profession, the most recent advances in orthodontics in the past three decades have been propelled by technological innovations including volumetric and surface 3D imaging and printing, advances in software that facilitate the derivation of diagnostic details, enhanced personalization of treatment plans and fabrication of custom appliances. Still, the use of these diagnostic and therapeutic technologies is largely phenotype driven, focusing mainly on facial/skeletal morphology and tooth positions. Future advances in orthodontics will involve comprehensive understanding of an individual's biology through omics, a field of biology that involves large-scale rapid analyses of DNA, mRNA, proteins and other biological regulators from a cell, tissue or organism. Such understanding will define individual biological attributes that will impact diagnosis, treatment decisions, risk assessment and prognostics of therapy. Equally important are the advances in artificial intelligence (AI) and machine learning, and its applications in orthodontics. AI is already being used to perform validation of approaches for diagnostic purposes such as landmark identification, cephalometric tracings, diagnosis of pathologies and facial phenotyping from radiographs and/or photographs. Other areas for future discoveries and utilization of AI will include clinical decision support, precision orthodontics, payer decisions and risk prediction. The synergies between deep 3D phenotyping and advances in materials, omics and AI will propel the technological and omics era towards achieving the goal of delivering optimized and predictable precision orthodontics.

Long-term morphometric changes in the anterior alveolar bone in adolescents and adults after space closure: A retrospective study

OBJECTIVES

To analyse the morphometric changes in the anterior alveolar bone of both the maxilla and mandible after space closure and retention for 18-36 mo in adults and adolescents.

MATERIALS AND METHODS

Forty-two subjects with 4 first premolars extracted followed by retracting anterior teeth were included and divided into two age groups: adult group (4 males, 17 females, mean age: 23.67 ± 5.29 y, treatment duration: 27.95 mo, retention duration: 26.96 mo, ANB: 4.8 ± 2.1, U1-L1: 117.2 ± 9.2, U1-PP: 120.2 ± 7.2, L1-MP: 99.2 ± 5.3) and adolescent group (6 males, 15 females, mean age: 11.52 ± 1.21 y, treatment duration: 26.18 mo, retention duration: 25.79 mo, ANB: 5.2 ± 2.1, U1-L1: 116.0 ± 8.6, U1-PP: 119.8 ± 4.9, L1-MP: 99.7 ± 4.9). Alveolar bone height and thickness of anterior teeth in both groups were measured using cone beam computed tomography (CBCT) imaging performed at the pretreatment (T1), posttreatment (T2) and retention phases (T3). One-way repeated-measure ANOVAs were performed to evaluate the alveolar bone changes. Voxel-based superimpositions were performed to measure the amount of tooth movement.

RESULTS

After orthodontic treatment, the lingual bone height and thickness of both arches and the labial bone height of the mandible decreased significantly in both age groups (P < .05). Most of the labial bone height and thickness of the maxilla in both groups remained unchanged (P > .05). After retention, the lingual bone height and thickness increased significantly in both age groups (P < .05). The amounts of increased height ranged from 1.08 to 1.64 mm in adults and from 0.78 to 1.21 mm in adolescents, and the amounts of increased thickness ranged from 0.23 mm to 0.62 mm in adults and from 0.16 mm to 0.36 mm in adolescents. Obvious movements of the anterior teeth during retention were not found (P > .05).

CONCLUSIONS

Although lingual alveolar bone loss occurred in adolescents and adults during orthodontic treatment, continuous remodelling occurred in the later retention phase, which provides a reference for clinical treatment planning of bimaxillary dentoalveolar protrusion.

Global network mapping research findings on orthognathic surgery and temporomandibular disorder

OBJECTIVES

The objective of this work is to assess the relationship between orthognathic surgery and temporomandibular disorders literature through a bibliometric analysis.

METHODS

A bibliographic search in line with the STROBE guidelines and the concepts of the Leiden Manifesto was performed on the Web of Science using the terms orthognathic surgery AND temporomandibular. A citation analysis and establishment of the more cited articles were performed. A graphical representation of the keywords was created with VOSviewer.

RESULTS

A total of 810 articles were analyzed in this study. The research revealed a significant increase in publications on this topic, particularly in English language articles and a high H-index. The publications represented 55 nations, with the highest number of articles coming from the USA. The discussion of highly cited articles covered various aspects such as the relationship between orthognathic surgery and TMD, including condylar resorption or displacement, predisposing factors, dentoskeletal and occlusion patterns, anatomical factors, osteotomy techniques, condylar positioning techniques, and emerging technologies for improved TMJ stability.

CONCLUSION

The analysis reveals an increasing research interest in this field, with a significant number of publications in English and a high citation rate per article, indicating the impact of the research. Various factors associated with TMD in orthognathic surgery are explored, including condylar alterations, predisposing factors, occlusion patterns, and surgical techniques. The study underscores the importance of thorough assessment, treatment, and monitoring of TMD in orthognathic surgery patients, while acknowledging the need for further research and consensus in management strategies.

Prevalence, clinical characteristics, and 3-dimensional radiographic analysis of supernumerary teeth in Guangzhou, China: a retrospective study

OBJECTIVE

The aim was to investigate the prevalence and clinical and 3-dimensional (3D) radiographic characteristics of supernumerary teeth (ST) in a paediatric dental population. The factors associated with ST eruption potential were analysed, and the optimal extraction time for nonerupted ST was discussed.

METHODS

A retrospective study was performed in a 13,336-participant baseline population aged 3-12 years for whom panoramic radiographs had been obtained in the hospital from 2019 to 2021. The medical records and radiographic data were reviewed to identify patients with ST. Both the demographic variables and ST characteristics were recorded and analysed .

RESULTS

In total, 890 patients with 1,180 ST were screened from the 13,336 baseline population. The ratio of males (679) to females (211) was approximately 3.2:1. Generally, ST occurred singularly and were frequently found in the maxilla (98.1%). A total of 40.8% of ST were erupted, and the 6-year-old age group presented the highest eruption rate (57.8%). The eruption rate of ST was highly negatively correlated with age. A total of 598 patients additionally underwent cone- beam computed tomography (CBCT). According to the CBCT images, the majority of ST were conical, normally oriented, palatally situated, nonerupted and symptomatic. The most common ST-associated complication was failed eruption of adjacent teeth. In addition, symptomatic ST were more common in the 7- to 8- and 9- to 10-year-old age groups. The eruption rate of ST was 25.3% among the patients who had undergone CBCT. A normal orientation and the labial position were significant protective factors for ST eruption, with odds ratios (ORs) of 0.004 (0.000-0.046) and 0.086 (0.007-1.002), respectively. Age and the palatal position were significant risk factors, with ORs of 1.193 (1.065-1.337) and 2.352 (1.377-4.02), respectively.

CONCLUSIONS

This study provides a detailed analysis of ST characteristics in 3-12 year old children. Age as well as the position and orientation of ST were reliable predictors of the ST eruption. An age of 6 years old may be the optimal time for extraction of nonerupted ST to maximize the utilization of eruption potential and reduce the incidence of ST-associated complications.

Accuracy of automated 3D cephalometric landmarks by deep learning algorithms: systematic review and meta-analysis

OBJECTIVES

The aim of the present systematic review and meta-analysis is to assess the accuracy of automated landmarking using deep learning in comparison with manual tracing for cephalometric analysis of 3D medical images.

METHODS

PubMed/Medline, IEEE Xplore, Scopus and ArXiv electronic databases were searched. Selection criteria were: ex vivo and in vivo volumetric data images suitable for 3D landmarking (Problem), a minimum of five automated landmarking performed by deep learning method (Intervention), manual landmarking (Comparison), and mean accuracy, in mm, between manual and automated landmarking (Outcome). QUADAS-2 was adapted for quality analysis. Meta-analysis was performed on studies that reported as outcome mean values and standard deviation of the difference (error) between manual and automated landmarking. Linear regression plots were used to analyze correlations between mean accuracy and year of publication.

RESULTS

The initial electronic screening yielded 252 papers published between 2020 and 2022. A total of 15 studies were included for the qualitative synthesis, whereas 11 studies were used for the meta-analysis. Overall random effect model revealed a mean value of 2.44 mm, with a high heterogeneity (I² = 98.13%, τ² = 1.018, p-value < 0.001); risk of bias was high due to the presence of issues for several domains per study. Meta-regression indicated a significant relation between mean error and year of publication (p value = 0.012).

CONCLUSION

Deep learning algorithms showed an excellent accuracy for automated 3D cephalometric landmarking. In the last two years promising algorithms have been developed and improvements in landmarks annotation accuracy have been done.

Evaluation of cuspid cortical anchorage with different sagittal patterns using cone-beam computed tomography: a retrospective study

BACKGROUND

No studies have focused on cortical anchorage resistance in cuspids, this study aimed to characterize the cortical anchorage according to sagittal skeletal classes using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 104 men and 104 women were divided into skeletal class I, II, and III malocclusion groups. Skeletal and dental evaluations were performed on the sagittal and axial cross-sections. One-way analysis of variance followed by least significant difference post-hoc tests was used for group differences. Multiple linear regression was performed to evaluate the relationship between influential factors and cuspid cortical anchorage.

RESULTS

All cuspids were close to the labial bone cortex in different sagittal skeletal patterns and had different inclinations. There was a significant difference in the apical root position of cuspids in the alveolar bone; however, no significant difference in the middle or cervical portions of the root was found between different sagittal facial patterns. The middle of the cuspid root was embedded to the greatest extent in the labial bone cortex, with no significant difference between the sagittal patterns. For all sagittal patterns, 6.03 ± 4.41° (men) and 6.08 ± 4.45° (women) may be appropriate root control angles to keep maxillary cuspids' roots detached from the labial bone cortex.

CONCLUSIONS

Comparison of skeletal class I, II, and III malocclusion patients showed that dental compensation alleviated sagittal skeletal discrepancies in the cuspid positions of all patients, regardless of the malocclusion class. Detailed treatment procedures and clear treatment boundaries of cuspids with different skeletal patterns can improve the treatment time, periodontal bone remodeling, and post-treatment long-term stability. Future studies on cuspids with different dentofacial patterns and considering cuspid morphology and periodontal condition may provide more evidence for clinical treatment.

DIAGNOSTIC PERFORMANCE OF CONE-BEAM COMPUTED TOMOGRAPHY TO DIAGNOSE IN VIVO/IN VITRO ROOT RESORPTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

This review analyses the diagnostic performance of cone-beam computed tomography (CBCT) for the in vivo/in vitro detection of external root resorption (ERR) and critically analyses current and past methods of measuring or classifying ERR in vivo/in vitro in terms of radiation doses and cumulative radiation risks.

METHODS

A diagnostic test accuracy (DTA) protocol was used for a systematic review of diagnostic methods following PRISMA guidelines. The protocol was registered with PROSPERO (ID: CRD42019120513). A thorough and exhaustive electronic search of 6 core electronic databases was performed, applying the ISSG Search Filter Resource. The eligibility criteria were designed [problem-intervention-comparison-outcomes (PICO) statement: Population, Index test, Comparator, Outcome] and methodological quality was assessed by QUADAS-2.

RESULTS

Seventeen papers were selected from a total of 7841 articles. Six in vivo studies were assessed as having a low risk of bias. The overall sensitivity and specificity of CBCT for diagnosis of ERR was 78.12% and 79.25%, respectively. The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%.

DISCUSSION

Most of the selected studies reported quantitative diagnoses with single linear measurements of ERR even though multislice radiographs were available. The cumulative radiation dose (μS) to radiation-sensitive structures, such as the bone marrow, brain and thyroid, was observed to increase using the 3-dimensional (3D) radiography methods reported.

CONCLUSIONS

The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%. The minimum and maximum effective doses of dental CBCT for external root resorption diagnosis are 34 μSv and 1073 μSv.

Evaluation and comparison of planum clival angle in three malocclusion groups : A CBCT study

PURPOSE

Cranial base flexure is an overlooked topic in craniofacial research. The aim of this retrospective observational study was to compare a new parameter, the planum clival angle (PCA), which represents cranial base flexure, in skeletal class I, II, and III malocclusions using cone beam computed tomographic images (CBCT) and correlate PCA with the stages of the fusion of the spheno-occipital synchondrosis (SOS).

MATERIALS AND METHODS

A total of 125 CBCTs were divided into two groups based on chronological age (19-25 years and 12-18 years). The CBCT images from 57 subjects (19-25 years old) were categorized into three groups based on their skeletal malocclusion for measuring PCA and cranial base angles (CBA). In the second group, comprising 68 CBCT data sets of individuals in the age group of 12-18 years, the PCA angle was correlated with stages of fusion of the SOS. Data were statistically analyzed using independent samples t test, one-way analysis of variance (ANOVA, intergroup), Pearson correlation, and χ2 test.

RESULTS

There was a statistically significant linear correlation (P < 0.001) between the two parameters PCA and CBA but no significant difference was found in PCAs between the three groups. One-way ANOVA to compare the PCA values in the three stages of fusion of the SOS revealed a highly significant relationship in male subjects (p < 0.001), thereby, suggesting that as fusion progresses, the planum clival angle increases. The χ2 test to compare the planum clival angle in males and females revealed that SOS fusion occurred earlier in females.

CONCLUSION

There is a constant dynamic change in the value of the parameter PCA that progresses until completion of SOS fusion. The SOS fuses earlier in females. Assessment of the stage of fusion of the SOS can be used in deciding whether growth modification of the craniofacial complex is still possible during orthodontic therapy.

Cone-beam computed tomography use in postgraduate orthodontic programs in North America and Europe

OBJECTIVES

Cone-beam computed tomography (CBCT) has emerged over recent decades as a rapid acquisition technology that allows practitioners to view the craniofacial complex in high spatial detail. This study aimed to assess the latest trend of CBCT use in postgraduate orthodontic programs in North America and Europe/Australia.

METHODS

An electronic multiple-choice survey was sent via email requesting anonymous participation of postgraduate orthodontic program directors: 73 in North America (as listed on the American Association of Orthodontists website) and 189 in Europe/Australia (as listed on the European Orthodontic Society website). Survey collection was over a 2-month period with two follow-up emails sent 2 weeks and 1 month after the initial email to each program director who had not responded. Responses were collected directly on Qualtrics for analysis.

RESULTS

The response rate was 46.6% (34 responses) for North America and 11.1% (21 responses) for Europe/Australia. Results revealed that 100% of respondents from North America had access to a CBCT scanner, while 90.48% of respondents (19 responses) from Europe/Australia had access. Most North American postgraduate orthodontic programs have CBCT scanners within their clinic, while most European/Australian programs do not, and they refer patients to the radiology department. Although there is a higher percentage of programs in North America compared to Europe/Australia that use CBCT as part of routine orthodontic records for all patients, most programs in both regions use CBCT imaging for specific diagnostic purposes and not for routine records.

CONCLUSION

Overall, North American programs have more access to CBCT scanners in postgraduate clinics and use CBCT imaging more routinely than European/Australian programs.

Application of digital positioning guide plates for the surgical extraction of multiple impacted supernumerary teeth: A case report and review of literature

BACKGROUND

An extra tooth in the normal tooth sequence in any region of the dental arch is regarded as a supernumerary tooth (SNT). Due to the large variation in location and morphology, the extraction of impacted SNTs is an extensive and complex procedure with high risks of several complications. This report presents a rare case of seven impacted SNTs in the bilateral upper and lower arch that were successfully extracted with the use of digital positioning guide plates.

CASE SUMMARY

In January 2022, a 21-year-old male was referred to our department with a chief complaint of pain in relation to tooth #36. Clinical examination showed a deep carious lesion with pulpal involvement in tooth #36 and lingual swelling of the bilateral mandibular posterior area. Radiographic examination revealed seven deeply impacted SNTs in the bilateral posterior area and bilateral impacted mandibular third molars. Based on these findings, the patient was diagnosed with bilateral, multiple impacted SNTs and tooth #36 chronic pulpitis. A root canal treatment and an all-ceramic crown restoration for tooth #36 were performed. An individualized digital positioning guide plate was designed by computer-aided design/computer-aided manufacturing technology and cone-beam computed tomography for extraction of the impacted SNTs. During the operation, the digital positioning guide plate allowed rapid positioning and exposure of the SNTs while avoiding adjacent important anatomical structures. At 3-month follow-up, regeneration of bone and soft tissues was visible.

CONCLUSION

The application of digital positioning guide plates is useful for the individualized and minimalized extraction of impacted supernumerary teeth.

Analysis of the feasibility of using deep learning for multiclass classification of dental anomalies on panoramic radiographs

The aim of the feasibility study was to construct deep learning models for the classification of multiple dental anomalies in panoramic radiographs. Panoramic radiographs with single supernumerary teeth and/or odontomas were considered the "case" group; panoramic radiographs with no dental anomalies were considered the "control" group. The dataset comprised 150 panoramic radiographs: 50 each of no dental anomalies, single supernumerary teeth, and odontomas. To classify the panoramic radiographs into case and control categories, we employed AlexNet, which is a convolutional neural network model. AlexNet was able to classify whole panoramic radiographs into two or three classes, according to the presence or absence of supernumerary teeth or odontomas. The performance metrics of the three-class classification were 70%, 70.8%, 70%, and 69.7% for accuracy, precision, sensitivity, and F1 score, respectively, in the macro average. These results support the feasibility of using deep learning to detect multiple dental anomalies in panoramic radiographs.

Association of the three-dimensional skeletal variables with self-recognition of facial asymmetry in skeletal Class III patients

OBJECTIVES

To investigate the association between three-dimensional (3D) skeletal variables and self-recognition of facial asymmetry in skeletal Class III patients.

MATERIALS AND METHODS

Questionnaires and cone beam computed tomography of 74 patients (42 men and 32 women; mean age: 22.8 ± 4.5 years) with skeletal Class III and facial asymmetry were collected retrospectively. Patients were classified into three groups: group Sy (recognition of symmetry), group NS (not sure), and group Asy (recognition of asymmetry), according to their responses to the questionnaires. To assess 3D anatomic differences in the maxillomandibular region, six 3D hard tissue variables: maxillary height, ramal length, frontal ramal inclination (FRI), lateral ramal inclination (LRI), mandibular body length (Mn BL), and mandibular body height (Mn BH) were compared among the three self-recognition groups. Six 3D hard tissue variables and Menton deviation were reduced into three factors and their association with the self-recognition of facial asymmetry was investigated.

RESULTS

Maxillary height, FRI, LRI, Mn BH, and Menton deviation demonstrated significant differences among the three self-recognition groups. The reduced factors, which consisted of transverse and vertical parameters, and vertical parameter of the mandibular corpus, demonstrated significant differences among the three self-recognition groups. The difference in Mn BH influenced the self-recognition of facial asymmetry.

CONCLUSIONS

Both the transverse and vertical parameter of the skeleton were determinant in self-recognition of facial asymmetry. Identification of the skeletal difference in the lateral view involving LRI and Mn BH should be included for assessment of facial asymmetry.

Precise extraction of impacted supernumerary tooth in the maxillary anterior region with a digital guide plate: A case report

RATIONALE

Removal of impacted supernumerary teeth requires precision and accuracy to prevent iatrogenic injury to important anatomical structures during dental surgery and to improve postoperative healing.

PATIENT CONCERNS

A 12-year-old girl visited our department for the assessment and management of her deviated front teeth.

DIAGNOSIS

Impacted supernumerary tooth extraction in the maxillary anterior region.

INTERVENTIONS

The digital guide plate was fabricated after the integration of cone beam computed tomography data with that obtained from scanning the patient's dental model. Impacted supernumerary tooth extraction was performed.

OUTCOMES

The use of the digital guide plate and planting instruments made the removal of the impacted supernumerary tooth less invasive, faster, and more accurate, whereas the wound was smaller, and the patient experience more comfortable.

LESSONS

Combining the digital guide plate with planting instruments offers a useful aid for the removal of impacted supernumerary teeth among the maxillary anterior region and is, thus, worth promoting.

Accuracy of dental arch form in customized fixed labial orthodontic appliances

INTRODUCTION

This study evaluated arch form accuracy with or without premolar extraction in customized fixed labial orthodontic appliance treatment.

METHODS

Setup and posttreatment digital models of 27 samples (15 extractions and 12 nonextractions) were selected and superimposed by best-fit surface-based registration in both the maxilla and the mandible. The facial axis points were identified and converted into Cartesian coordinates. A sixth-order polynomial equation was used to fit dental arches. Arch discrepancies (the mean distance between 2 arch forms) and similarities were compared between extraction and nonextraction groups, maxilla and mandible, and anterior and posterior arches.

RESULTS

The arch discrepancy between extraction and nonextraction groups showed no statistically significant difference, but a statistically significant difference in arch similarity was found in the mandible. There were statistically significant differences between anterior and posterior arch discrepancies in the extraction (mandible) and the nonextraction (maxilla and mandible) groups. However, no statistically significant correlation was shown between anterior and posterior arch discrepancies. The arch similarities were 96.18% and 97.38% in the maxilla and 96.01% and 97.49% in the mandible between extraction and nonextraction groups. Arch form discrepancies and similarities showed a moderate correlation but no statistically significant differences between the maxilla and the mandible.

CONCLUSIONS

In customized fixed labial orthodontic appliance treatment, arch form setup can be accurately achieved with and without premolar extraction. Anterior arch form acquires fewer discrepancies than the posterior arch, and overcorrection should be added to the end of the customized archwire to reduce posterior arch discrepancies. The discrepancy of the maxillary and mandibular arches is interrelated, and adjustments should be made on both maxillary and mandibular archwires to correct single-jaw transverse malposition.

Assessment of Growth Changes in the Width of Dental Arches Caused by Removable Appliances over a Period of 10 Months in Children with Malocclusion

(1) Background: A large number of patients of orthodontic clinics are diagnosed with improper jaw relationships. Intraoral scanners have become an important part of orthodontic practice and provide an opportunity to measure the changes in the width of dental arches. The purpose of the study was to evaluate the impact of removable appliances used over a 10-month period on growth changes in children with narrowed jaw dimensions. (2) Methods: Twenty four patients were included in the study (a study group—patients, treated with removable appliances in the upper dental arch for a minimum of 10 months; a control group—patients with no craniofacial abnormalities and who did not require orthodontic treatment). A panoramic radiograph and digital intraoral scan were taken, followed by palatal width measurements in Ortho-CAD before treatment, and after a period of 10 months of treatment with removable appliances. (3) Results: After a period of 10 months of the treatment, the study group had a statistically significantly greater mean change in the anterior width of the upper dental arch than the control group. (4) Conclusions: The use of removable appliances in children with narrowed maxillary transverse dimension contributes to offsetting growth changes in comparison to children with normal occlusion.

Relationship between non-syndromic oral clefts and cancer: a systematic review and meta-analysis

OBJECTIVE

To summarize the clinical evidence on the relationship between cancer and non-syndromic oral cleft (NSOC).

METHODS

The review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, and a literature search was conducted in six databases and gray literature. Studies published in any language mentioning cancer in patients with NSOC and their relatives and NSOC in patients with cancer and their relatives were included. Risk of bias was assessed using the Joanna Briggs Institute appraisal tool. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) assessment. After a 2-step selection process, 33 studies were included: 17 case-control studies, 13 cross-sectional studies, and 3 case reports.

RESULTS

The study evaluated 206,096 patients from 20 countries. Of these, 0.35% of patients with cancer (95% CI: 0.0% to 1.1%; I² = 86%), 3.0% of relatives of patients with cancer (95% CI: 1.19% to 5.46%; I² = 55%), and 0.26% of controls (95% CI: 0.0% to 0.83%; I² = 87%) had NSOC. Among the studies that examined the prevalence of cancer, 2.4% (95% CI: 0.0% to 19.3%; I² = 99%) of patients with NSOC, 15.4% of relatives of patients with NSOC (95% CI: 2.0% to 37.6%; I² = 99%), and 5.3% of controls (95% CI: 0.0% to 22.8%; I² = 99%) had cancer. Although no relationship was observed between the risk of cancer in patients with NSOC and the risk of NSOC in patients with cancer, there was an association for an increased risk of cancer in relatives of patients with NSOC (OR: 9.96, 95% CI: 1.55 to 63.99; P = 0.01) and a significant association for the NSOC risk in relatives of patients with leukemia (OR: 9.31; 95% CI: 1.13 to 76.67; P = 0.03).

CONCLUSION

Our findings demonstrate an increased risk of cancer in relatives of patients with NSOC and that relatives of patients with leukemia were more frequently affected by NSOC. Together, these findings can help guide cancer screening in patients with NSOC and their relatives and shed light on the risk of NSOC in families with a history of cancer.

The Effects of Additional Filtration on Image Quality and Radiation Dose in Cone Beam CT: An In Vivo Preliminary Investigation

Purpose. The aim of this study was to investigate the effect of reduced radiation doses on the image quality of cone-beam computed tomography scans and the suitability of such imaging for orthodontics, oral surgery, dental implantology, periodontology, and endodontology. Materials and Methods. Cone-beam computed tomography scans of a live patient were performed using seven attenuation filters with increased thickness to decrease the effective radiation dose from 22.4 to 1.8 μSv, and the effects of different radiation doses on image quality were further analysed. Quantitative image quality was calculated using dedicated measures, such as signal and contrast-to-noise ratio and sharpness. A panel of five certified raters assessed the cone-beam computed tomography scans qualitatively. Nine anatomical structures relevant to dentistry were identified, and the overall acceptance was assessed. Results. Linear reduction of the effective radiation dose had a nonlinear effect on image quality. A 5-fold reduction in the effective dose led to acceptable quantitative and qualitative image quality measures, and the identification rate of dental anatomical structures was 80% or greater. The use of less than 40% of the reference dose was unacceptable for all dental specialties. Conclusions. The ideal radiation dose for specific diagnostic requirements remains a patient-related and specialty-related decision that must be made on an individual basis. Based on the results of this study, it is possible to reduce exposure in selected patients, and at the same time obtain sufficient quality of images for clinical purposes.

A randomized controlled trial: evaluation of efficiency and safety of a novel surgical guide in the extraction of deeply impacted supernumerary teeth in the anterior maxilla

Background

Preoperative X-ray and cone-beam computed tomography (CBCT) are helpful for locating supernumerary teeth, but the images cannot be transferred to the operation. To design a novel surgical guide plate for intraoperative navigation, we transfer the patient's oral CBCT and gypsum model scan data to a computer for analysis. In our study, we evaluate the efficiency and safety of a novel surgical guide plate for the extraction of deeply impacted supernumerary teeth (DIMSNT) in the anterior maxilla.

Methods

Forty patients treated at the Department of School & Hospital of Stomatology, Wenzhou Medical University from March 2019 to December 2020 with DIMSNT (type II/III according to Liu et al.) in the anterior maxilla were randomly divided into 2 groups (20 patients for each group) for the extraction. For group I, a novel surgical guide was selected using CBCT and gypsum model scan. In contrast, for group II who underwent freehand surgery, only the CBCT data was used. The evaluation of operation time, complications, satisfaction score, and the number of cases that underwent extraction immediately after removing the bone were performed to assess the efficiency and safety of this novel surgical plate.

Results

All patients completed the surgery successfully. The guides for group I had a good application effect. Group I's operation time (23.35±5.39 min) was shorter than group II (29.60±9.76 min) (P=0.0194). The average pain degree of group I (1.8±1.08) was significantly less than group II (2.82±1.68) (P<0.05). The average swelling score of group I (34) was significantly less than group II (44.7). Patient satisfaction was significantly higher in group I (8.95±1.05) than in group II (7.90±1.51) (P=0.0152).

Conclusions

The novel surgical guide assisted with DIMSNT extraction have been effective in improving the quality of the surgery, patient satisfaction, and reduce its difficulty and duration. We can construct a surgical guide plate to guide the incision and osteotomy in DIMSNT surgery through the data analysis of DIMSNT on computer, which has a broad application prospect for clinical use.

Trial registration

Chinese Clinical Trial Registry ChiCTR2100054523.

Effects of Photobiomodulation on the Upper First Molar Intrusion Movement Using Mini-Screws Anchorage: A Randomized Controlled Trial

Objective: The aim of this study was to quantify the changes obtained when the molar intrusion movement is complemented by photobiomodulation (PBM). Background: A common problem in adult patients is the super-eruption of maxillary molars caused by the loss of the antagonist tooth. Super-erupted molars impair oral rehabilitation and can cause both occlusal and functional problems. There is increasing research confirming the benefits of adjunctive PBM during orthodontic treatment. Methods: Twenty patients with indication of a maxillary first molar intrusion for oral rehabilitation were selected. Patients were randomized into two groups to receive orthodontic intrusion (control group) or the same treatment complemented by PBM (PBM group) in repeated doses (days 0, 1, 2, 3, 4, and 7 from the start of the intrusion and in each monthly follow-up) by using a low-power red laser diode (670 nm, 150 mW, 12 min around the molar). Plaque index (PI), probing depth (PD), and bleeding of probing (BOP) were assessed at 0, 1, 2, 3, and 6 months. Stereolithography models generated from an intraoral scanner were taken at 0, 3, and 6 months and cone beam computed tomography (CBCT) records were taken at 0 and 6 months. Mean intrusion distance, mean intrusion velocity, and volumetric resorption were calculated. Results: Periodontal clinical assessments (PI, PD, and BOP) and mean intrusion distance or mean intrusion velocity yielded no differences (p > 0.05) between groups. However, PBM group showed lower values of all these scores during the first 3 months. Intraoral scanner and CBCT were equally effective in accurately monitoring the intrusion distance (p > 0.05). CBCT records allowed volumetric evaluation of the root resorption process, being lesser in the PBM group, but not significantly (p > 0.05). Conclusions: During orthodontic intrusion process, the adjunctive application of PBM may provide better periodontal records and lower progression of root resorption at the expense of a little lower intrusion distance and velocity.

Correlation of spheno-occipital synchondrosis fusion stages with a hand-wrist skeletal maturity index: A cone beam computed tomography study

OBJECTIVES

To examine the correlation between spheno-occipital synchondrosis fusion stages and the hand-wrist skeletal maturity index.

MATERIALS AND METHODS

Digital records of 164 individuals (77 males, 87 females) aged 10 to 18 years old were examined. Three-dimensional CBCT scans and hand-wrist two-dimensional radiographs were scored for the spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity index, respectively. Statistical analyses were performed for associations using R software with a significance threshold of P< .01.

RESULTS

A significant positive relationship was demonstrated between spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity in both sexes. The Kendall's rank correlation τ between hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion percentage were high and positive in males and females (r = .74 and r = .71, respectively).

CONCLUSIONS

The significant, positive relationship between the hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion stages support the idea of using spheno-occipital synchondrosis fusion as a biological indicator for craniofacial and mandibular growth spurt prediction.

Diagnostic accuracy of lateral cephalograms and cone-beam computed tomography for the assessment of sella turcica bridging

INTRODUCTION

The purpose of this research was to assess the diagnostic accuracy of sella turcica bridging on lateral cephalograms when compared with true sella turcica bridging determined via cone-beam computed tomography (CBCT).

METHODS

A cross-sectional study was conducted using CBCT images from which lateral cephalograms were generated. The study included 185 subjects (118 females and 67 males; age range, 10-30 years; mean age, 16.63 ± 4.20 years). Sella turcica landmarks and related measurements were calculated for both diagnostic modalities and analyzed by 1 examiner. Subjects were classified into 1 of 3 outcome groups: no bridging, partial bridging, and complete bridging. Diagnostic accuracy was evaluated using sensitivity, specificity, positive and negative predictive values, and receiver operator characteristic curves.

RESULTS

Ten patients were diagnosed as complete bridging on CBCT, whereas 31 patients were diagnosed as complete bridging on lateral cephalogram. Although the lateral cephalogram detected all subjects with complete bridging, it incorrectly classified 12% of subjects. The percent agreement between both diagnostic methods was 55.68%, with a kappa statistic of 0.22 on the right sella turcica and 0.20 on the left sella turcica, indicating fair but statistically significant agreement. The overall accuracy of lateral cephalograms as a diagnostic modality in discriminating between no bridging and partial bridging was good as determined with the area under the curve values of 0.86 and 0.85 for right and left sides, respectively.

CONCLUSIONS

Although lateral cephalograms overestimate patients with complete bridging compared to CBCTs, they are a suitable screening modality for accurately suggesting complete sella turcica bridging and differentiating between patients with no bridging and partial bridging.

Reliability and accuracy of automatic segmentation of mandibular 3D models on linear measurements

OBJECTIVE

Evaluate if automatic segmentation of mandibular three-dimensional (3D) models is reliable and accurate.

MATERIALS AND METHODS

Eight dry mandibles with eight silica markers were scanned in the i-CAT Classic device (Imaging Sciences International). Automatic segmentation was performed using nine standard preset thresholds in the Dolphin software (Dolphin Imaging & Management Solutions). Three observers individually made twice eight linear measurements on the mandibular 3D models. Another observer made physical measurements, twice as well, on the dry mandibles. Reliability and accuracy were evaluated with intraclass correlation coefficients (ICCs), Dahlberg's formula, Bland-Altman analyses, and changing bias with regression analyses.

RESULTS

Inter-observer and intra-observer ICCs and Dahlberg's error were ≥ 0.75 and ≤ 1.0 mm, respectively, for all measurements. Inter-observer agreement between mandibular 3D models and physical measurements ranged from -0.37 to 0.91 mm.

CONCLUSIONS

Linear measurements made on mandibular 3D models obtained using standard preset thresholds are reliable and accurate. However, additional studies are necessary to confirm this hypothesis for clinical applications.

CLINICAL RELEVANCE

Since the 3D models are useful for diagnostics and surgical planning, it is necessary to determinate whether the linear measurements made on 3D models obtained by automatic segmentation are sufficiently reliable and accurate.

Evaluation of the palatal bone in different facial patterns for orthodontic mini-implants insertion: A cone-beam computed tomography study

Objective:

Evaluate the height, thickness and cortical density of the palatal bone of adults with different vertical facial patterns using Cone-Beam Computed Tomography (CBCT).

Methods:

This study analyzed 75 CBCTs of patients between 18 and 35 years old (45 men and 30 women). The CBCTs were classified into three groups based on their facial pattern: normodivergent, hypodivergent and hyperdivergent as determined from lateral cephalograms synthesized from the CBCTs. The height, cortical thickness and cortical density of the palatal bone were measured at 4, 8, 12, 16 and 20mm posterior to the incisive foramen, and at 3, 6 and 9mm lateral to the midpalatal suture. ANOVA with Tukey post-hoc tests were used for analysis of the data, at significance level of p< 0.05.

Results:

The hypodivergent pattern had a significant difference and the greatest height and cortical thickness of the palatal bone, followed by the hyperdivergent and the normodivergent patterns. No significant differences were found in minimum and maximum values of cortical density.

Conclusion:

The palatal bone is a favorable anatomical area to install different orthodontic temporary anchorage devices (TADs), where individuals with the hypodivergent vertical facial pattern have a higher height and cortical thickness of the palatal bone, followed by the hyperdivergent pattern and finally the normodivergent pattern. No significant differences in the cortical density of the palatal bone in the three facial patterns were found.

Comparative Reliability Assessment of Tooth Volume Measurement with Different Three-Dimensional Imaging Software

Objective. To evaluate the in vivo tooth volume through VRMesh and 3Matic programs and to compare the measurements to the physical volume. So, the aim of the study was to ensure the reliability and sensitivity of the three-dimensional software (VRMesh and 3Matic) in measuring tooth volume. Material and Methods. The volume of 26 extracted upper first premolars from orthodontic patients who had CBCT before orthodontic treatment were measured. Two different commercial programs, which were VRMesh and 3Matic, were used to calculate the volume of the segmented upper first premolar from CBCT. The in vivo tooth volume was compared to the physical tooth volume to examine the accuracy of the two software in measuring the tooth volume. Results. The difference between the mean of the in vivo and in vitro tooth volume measurements was too small, making it clinically nonsignificant. ANOVA test was used as a statistical tool, and no statistically significant difference was noticed among the measurements. The values were normally distributed when tested for normality by Kolmogorov-Smirnov and Shapiro-Wilk test. $\mathit{P}$ value less than or equal to 0.05 ( $\mathit{P}\le 0.05$ ) was considered statistically significant. Conclusion. The assessment of the in vivo tooth volume measurement with different three-dimensional imaging software (VRMesh and 3Matic) programs in comparison with the tooth physical volume is reliable. The use of a mouse pen during the refining stage of the segmentation may have increased the accuracy of the procedure. The determined in vivo tooth volumes are dependable and can be applied in orthodontic diagnosis and treatment planning.

Sella Turcica Morphology in Patients With Genetic Syndromes: Protocol for a Systematic Review

Background

The sella turcica is an important anatomical reference used in orthodontics and the evaluation of craniofacial growth. Studies have found an association between variations in sella turcica morphology in patients with certain syndromes affecting the craniofacial complex. It is hypothesized that each related syndrome or pathological condition is associated with a specific pattern of malformation of the sella turcica.

Objective

This study outlines the protocol for a systematic review that aims to determine if genetic syndromes involving the craniofacial complex are associated with abnormal radiographic sella turcica morphology and if there is a pattern of malformation that is consistent with each syndrome.

Methods

An electronic database search was conducted using a planned search strategy to identify relevant studies. We included primary studies evaluating the morphology of the sella turcica based on imaging from a lateral view. Specifically, only studies with postnatal human participants with genetic syndromes involving the craniofacial complex were included in this review. We placed no restrictions on the language or time frame of these studies. Based on the search findings, studies were further screened for relevance and eligibility by two independent reviewers. Data were extracted from the selected studies. We assessed the selected studies for risk of bias and quality by using risk of bias tools from the Joanna Briggs Institute. We will provide a narrative synthesis of our findings and a structured summary based on prespecified themes.

Results

The protocol is registered with PROSPERO (#CRD42019148060) and approved by the University of Western Cape Biomedical Science Research Ethics Committee (BM205/3). The literature search was conducted in September 2019 and updated in July 2020. The study was completed in August 2020, and the findings will be published in an open-access journal.

Conclusions

The results of this systematic review are expected to provide a comprehensive list of morphological variations of the sella turcica, which will aid in the identification of syndromes associated with the craniofacial complex. We also expect to identify patterns of sella turcica morphology that highlight genotype-phenotype correlations, thus adding to the body of evidence relating to genetics and craniofacial malformations.

Trial Registration

PROSPERO International Prospective Register of Systematic Reviews CRD42019148060; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=148060

International Registered Report Identifier (IRRID)

RR1-10.2196/16633

Epidemiological, clinical, radiographic characterization of non-syndromic supernumerary teeth in Chinese children and adolescents

OBJECTIVE

This retrospective study was purposed to evaluate epidemiological, clinical, and 3D radiological features of supernumerary teeth (ST) in a non-syndromic Chinese children and adolescent dental population.

MATERIALS AND METHODS

Original cone-beam CT (CBCT) data from 18,861 patients aged from 6 to 17 years with dental maxillofacial diseases treated in a Chinese dental hospital from June 2012 to December 2018 were utilized to screen patients with ST. Diagnosis and characterizations of ST were analyzed by CBCT coupled with 3D reconstruction. All relevant epidemiological, clinical, and radiographic details about ST were collected and statistically analyzed.

RESULTS

Among total 18,861 patients, 2,768 ST were identified in 1984 subjects with a prevalence of 10.52% and a male:female ratio of 1.86:1. Majority of ST were single, conical, inverted, impacted, and located in maxilla anterior region. ST-associated complications mainly included malposition, rotation, and impaction of adjacent teeth, which were notably associated with morphology and position of ST.

CONCLUSION

The prevalence of ST in Chinese children and adolescent dental population was 10.52% and tended to present as single, conical, inverted, and impacted, which resulted in abnormalities of neighboring teeth. Our outcomes are beneficial for clinicians to more comprehensively understand the incidence, characterization, and clinical treatment planning of ST in dental children and adolescents.

Can modifying shielding, field of view, and exposure settings make the effective dose of a cone-beam computed tomography comparable to traditional radiographs used for orthodontic diagnosis?

OBJECTIVES

To analyze the effect of changes in exposure settings, field of view (FOV), and shielding on radiation to an adult and child phantom from cone-beam computed tomography (CBCT) imaging compared to panoramic and lateral cephalometric radiographs.

MATERIALS AND METHODS

The effective dose to an adult and child anthropomorphic phantom by the CS 9300 using various scan protocols was recorded. Absorbed radiation was measured with optically stimulated luminescence dosimeters and effective dose calculated using 2007 International Commission on Radiological Protection tissue weighting factors. Scan protocols included different FOVs, voxel sizes, and standard versus low-dose protocols. Radiation shielding was used when it did not interfere with FOV. Panoramic and lateral cephalometric radiographs were taken with the Orthophos SL.

RESULTS

Even with shielding, smaller FOVs, and increased voxel sizes, the effective dose of standard CBCT scans was higher than panoramic and lateral cephalometric radiographs. A shielded limited FOV standard scan combined with a lateral cephalometric radiograph resulted in a lower dose (P < .001) than a full FOV standard scan. Low-dose shielded scans resulted in significant dose reductions to the adult (P < .05) and child (P < .001) phantoms compared to the respective panoramic and lateral cephalometric radiographs combined. Image quality analysis was not possible with radiation equivalent phantoms.

CONCLUSIONS

Unlike standard CBCTs, shielded low-dose CBCT protocols in the CS 9300 have lower effective doses than conventional radiographs for adult and child phantoms. If high resolution and cranial base visualization are necessary, combining a shielded LFOV standard exposure with a cephalometric radiograph is recommended.

Diagnostic paths for a mouth-breathing patient

INTRODUCTION

The clinical choice of diagnostic tests or treatment options is determined by the probability that the value of their execution (called the warrant for the test) exceeds their cost, and by their usefulness. The purpose of this study was to determine the warrant and usefulness of STOP-Bang, an obstructive sleep apnea screening questionnaire, and cone-beam computed tomography (CBCT) information about the minimal cross-sectional area for referring a mouth-breathing patient to a sleep specialist and for modifying planned orthodontic treatment.

METHODS

A branching survey was used to identify the prominence of paths between the presenting situation, 2 diagnostic tests, and 2 referral and/or treatment options. A description was given of a hypothetical patient: an overweight, mouth-breathing female teenager. Path analysis was used as a method for quantifying diagnostic warrant and usefulness.

RESULTS

There was a wide variation among the 125 orthodontists who responded to the survey. All paths were chosen. The use of tests altered the referral (χ² = 8.039; P = 0.03) and/or treatment decisions (χ² = 12.636; P = 0.005). Ownership of a CBCT system significantly influenced the use of this diagnostic test, with owning a CBCT system resulting in greater use in-office (χ² = 50.416; P <0.001) and greater use in the study (χ² = 22.959; P <0.001). The usefulness of the diagnostic tests could not be determined directly because common values were used for each test, but the variation in the use of this standard stimulus was very large, indicating personal differences in the interpretation of actual data.

CONCLUSIONS

Wide variation in the choice and interpretation of diagnostic tests for referral and orthodontic treatment modification relative to airway condition exists among orthodontists. Diagnostic path analysis is a potentially useful model for studying how practitioners make decisions independent of research evidence.

A systematic approach on the frequency of cleft lip/palate in pediatric patients with leukemia

PURPOSE

The purpose of this study was to reveal the frequency between cleft lip/palate and leukemia in pediatric patients by a systematic analysis of the current literature.

MATERIALS AND METHODS

Electronic search on three database (PubMed, Web of Science, Cochrane) was carried out using the following keywords: cleft lip, cleft palate, facial cleft, oral cleft, orofacial cleft, leukemia, acute myeloid leukemia, acute lymphocytic leukemia, lymphoma. Studies published until March 2020 reporting an association between leukemia and cleft lip/palate (CL/P) were included in our research.

RESULTS

Five articles (2 case-controls, 3 cohorts), met the inclusion criteria. Case-control studies involved 268 patients with acute lymphocytic leukemia (ALL) and 177 patients with acute myeloid leukemia (AML), of which 9 patients had CL/P. The cohorts studies involved 10 patients with ALL, of which 6 patients with CL/P, 2 patients with cleft palate and 1 patient with cleft lip and palate.

CONCLUSION

This research was able to indicate a limited evidence of the association between CL/P and leukemia. In order to draw a clear conclusion, studies with larger cohorts are needed to establish this correlation.

[Application of digital positioning guide plate in extraction of impacted supernumerary teeth]

OBJECTIVE

To explore the application of digital positioning guide plate in extraction of impacted supernumerary teeth and evaluate its clinical efficacy.

METHODS

From March to August, 2019, 30 patients with labial impacted supernumerary teeth treated in the Department of Oral and Maxillofacial Surgery, Stomatological Hospital, Southern Medical University were enrolled in this study. Fifteen of the patients were treated with digital positioning guide plate to remove the impacted supernumerary teeth (test group). According to the CBCT data and the dentition model of the patients, the positioning guide plate was positioned by avoiding the important anatomical structure with the tooth-bone surface as the support to design the soft tissue incision line and bone tissue exposure range. The other 15 patients who were treated without the use of the guide plate for operation served as the control group. The design time, tooth searching time, operation time and complications were compared between the two groups.

RESULTS

The positioning guide plate was well attached during the operation and allowed quick location of the supernumerary teeth while helping to expose the supernumerary teeth and avoid the damage of the adjacent important anatomical structures. The pre-operative design time was 50 ± 5 min in the test group and 0 min in the control group. The average time of tooth finding in the test group was 5±2 min, as compared with 10±3 min in the control group (t=15.40, P &lt; 0.01); the average time of operation was significantly shorter in the test group than in the control group (25±4 min vs 45±6 min; t=35.50, P &lt; 0.01). No intraoperative complications occurred in the test group, and slight deviation occurred in one case in the control group.

CONCLUSIONS

The application of digital positioning guide plate in extraction of embedded supernumerary teeth can significantly shorten the time of tooth finding, reduce the difficulty of operation, and improve the quality of operation.

Evaluation of the accuracy of electronic apex locators, cone-beam computed tomography, and radiovisiography in primary teeth: An in vitro study

Electronic apex locators (EALs), cone-beam computed tomography (CBCT), and radiovisiography (RVG) claim to determine of working length (WL) in primary molar teeth. To evaluate the accuracy of WL determination by using three EALs, RVG, and CBCT imaging in extracted human primary molar teeth with/without root resorption. Twenty extracted primary molar teeth with resorption and 20 extracted primary molar teeth without resorption were used. After measuring actual lengths (AL) (Group 1), the electronic WL measurements were performed by using three different EALs [COXO C Smart-1 Pro (Group 2), iPex (Group 3), and Apex ID (Group 4)]. Two different image sets were obtained as follows: CBCT imaging (Group 5) and RVG (Group 6). AL measurements performed with an endodontic measuring ruler and compared with the EAL, CBCT, and RVG image measurements. For all groups, there were no significant differences between the teeth with resorption and without. There were no significant differences in measuring methods from AL and between the methods used (p > .05). When electronic and radiographic method were compared in different frequency ranges, there was no statistically significant difference (p > .05). This study showed that EALs, CBCT, and RVG have high accuracy in primary molar teeth both with resorption and without root resorption and can be used for determining WL.

Root changes in buccal versus palatal maxillary impacted canines of adults: A longitudinal and retrospective 3-dimensional study before and after orthodontic traction

OBJECTIVE

Maxillary impacted canines (MIC) could suffer root changes after canine traction. The aim of this study was to evaluate the 3-dimensional root changes in buccal versus palatal MIC after orthodontic traction.

MATERIALS AND METHODS

This longitudinal and retrospective study included pre-treatment and after traction cone beam computed tomography scans (CBCTs) of 30 subjects with unilateral/bilateral MIC. A total of 43 MIC were divided into 2 groups: buccal (n=17) or palatal (n=26). Root changes in length and area after orthodontic traction were measured at sagittal, coronal and axial sections. Intergroup comparison was carried out by t or U Mann-Whitney tests, depending on normality. Multiple linear regression analysis was used to evaluate the influence of all predictor variables on root changes (P<0.05).

RESULTS

Significant difference between groups was found for root area changes in the upper limit of the cervical third at axial section that showed greater appositional values for the palatal impacted canine group (-1.18mm²) and resorptive values for the buccal impacted canine group (0.62mm²) (P=0.024). Position of impaction palatal influenced the increase of root area in the coronal section and in the upper limit of the cervical third at axial section. Age directly influenced the decrease of total length and root area in sagittal and coronal sections, respectively.

CONCLUSION

Orthodontic traction of MIC produced an important appositional root change in the palatal impaction group in the axial root area of the upper limit of the cervical third. Impaction position and age influenced the increase and decrease of root area and length of some specific radicular regions.

Influence of tongue volume, oral cavity volume and their ratio on upper airway: A cone beam computed tomography study

Background

Our study aimed to measure the tongue volume (TV), oral cavity volume (OCV), and their ratio (TV/OCV) and correlate with upper airway using cone-beam computed tomography (CBCT).

Method

The volume of oral cavity, tongue and upper airway were obtained by the manual process of segmentation of CBCT data of 15 subjects. The mean age of the sample was 21.86 years (range 15-33 years). Segmentation of the upper airway, tongue and oral cavity was performed manually using Mimics 11.0 (Materialise, Leuven, Belgium) software at different thresholds for air and the tongue. The Hounsfield units (HU) for airway volume of the different facial region ranged from -1024 to -500. For tongue volume, Hounsfield units (HU), ranging from -200 to 200 was calculated.

Results

A significant negative correlation between TV/OCV and oropharynx (r = - 0.51; P = 0.04), TV/OCV and oral cavity airway volume (r = - 0.74; P = 0.002) was found. There was a significant and a positive correlation with TV/OCV and tongue volume (r = 0.65; P = 0.009).

Conclusion

A significant negative correlation established between TV/OCV, oropharynx and oral cavity airway volume. This finding indicates an influence tongue volume, oral cavity volume and their ratio on patency of the oropharynx.

3D superimposition of craniofacial imaging-The utility of multicentre collaborations

Clinical applications of 3D image registration and superimposition have contributed to better understanding growth changes and clinical outcomes. The use of 3D dental and craniofacial imaging in dentistry requires validate image analysis methods for improved diagnosis, treatment planning, navigation and assessment of treatment response. Volumetric 3D images, such as cone-beam computed tomography, can now be superimposed by voxels, surfaces or landmarks. Regardless of the image modality or the software tools, the concepts of regions or points of reference affect all quantitative of qualitative assessments. This study reviews current state of the art in 3D image analysis including 3D superimpositions relative to the cranial base and different regional superimpositions, the development of open source and commercial tools for 3D analysis, how this technology has increased clinical research collaborations from centres all around the globe, some insight on how to incorporate artificial intelligence for big data analysis and progress towards personalized orthodontics.

Adding Depth to Cephalometric Analysis: Comparing Two- and Three-Dimensional Angular Cephalometric Measurements

INTRODUCTION

Lateral cephalometric radiographs (LCR) have been the standard tool used for cephalometric analysis in craniofacial surgery. Over the past decade, a three-dimensional (3D) revolution in cephalometric analysis and surgical planning has been underway. To date, research has not validated whether cephalometric measurements taken from two-dimensional (2D) and 3D data sources are equivalent and interchangeable. The authors sought to compare angular cephalometric measurements taken with 2D and 3D modalities.

METHODS

Sixty-two head CT scans (36 females, 26 males) with an average age of 63 ± 20 years were studied. Twelve cephalometric angular measurements were taken from 3D reconstructed skulls using the software package Mimics 19.0 (Materialize; Leuven, Belgium). These same facial angles were measured from 2D lateral cephalograms reconstructed from the original CT scans using Dolphin 11.9. Measurements taken with both techniques were compared for agreement using a paired t test. Intra-class correlation coefficient assessment was used to determine inter-rater reliability. Statistical significance was set at P < 0.05.

RESULTS

Five of the 12 angular measurements (SNA, SNB, MP-FH, U1-SN, and U1-L1) demonstrated statistically significant differences (P < 0.05) between the 2D and 3D analyses. All of these differences were less than the standard deviations for the respective measure.

CONCLUSION

The differences between angular cephalometric values obtained from 2D LCRs and 3D CT reconstructions are small. This supports the practices of using 2D and 3D cephalometric data interchangeably in most applications. Clinicians must be selective in which measures they employ to maximize accuracy and care must be taken when measuring dental inclination with lateral cephalograms.

Clinical indications and radiation doses of cone beam computed tomography in orthodontics

Cone beam computed tomography can be used in pediatric population when a tridimensional analysis of dental and maxillofacial bone structures is required. Even though CBCT is considered a low dose radiological examination, ionizing radiation is a known human carcinogenic factor. Furthermore, biological effects are more important in young patients because of their higher radiosensitivity. Orthodontic treatment is typically initiated at young ages and the most common radiographs at this age are dental. This makes it important to quantify the effects of diagnostic radiographs, in particular of CBCT, due to the fact that the radiation doses are higher compared to conventional radiological methods. So far, the carcinogenic response after low dose radiation exposure is not fully understood in the scientific literature. The aim of our review was to emphasize the main indications of CBCT in orthodontics and to evaluate the radiation doses and potential risks of CBCT irradiation of pediatric patients.

Cone-Beam Computed Tomography in Orthodontics

Unlike patients receiving implants or endodontic treatment, most orthodontic patients are children who are particularly sensitive to ionizing radiation. Cone-beam computed tomography (CBCT) carries risks and benefits in orthodontics. The principal risks and limitations include ionizing radiation, the presence of artifacts, higher cost, limited accessibility, and the need for additional training. However, this imaging modality has several recognized indications in orthodontics, such as the assessment of impacted and ectopic teeth, assessment of pharyngeal airway, assessment of mini-implant sites, evaluation of craniofacial abnormalities, evaluation of sinus anatomy or pathology, evaluation of root resorption, evaluation of the cortical bone plate, and orthognathic surgery planning and evaluation. CBCT is particularly justified when it brings a benefit to the patient or changes the outcome of the treatment when compared with conventional imaging techniques. Therefore, CBCT should be considered for clinical orthodontics for selected patients. Prescription of CBCT requires judicious and sound clinical judgment. The central question of this narrative review article is: when does CBCT add value to the practice of orthodontics? To answer this question, this article presents discussion on radiation dosage of CBCT and other imaging techniques used in orthodontics, limitations of CBCT in orthodontics, justifying the use of CBCT in orthodontics, and the benefits and evidence-based indications of CBCT in orthodontics. This review summarizes the central themes and topics in the literature regarding CBCT in orthodontics and presents ten orthodontic cases in which CBCT proved to be valuable.