CBCT in orthodontics: a systematic review on justification of CBCT in a paediatric population prior to orthodontic treatment

Timing of Spheno-Occipital Synchondrosis Ossification in Children and Adolescents with Cleft Lip and Palate: A Retrospective Case-Control Study

Background: Cleft lip and palate (CLP) can affect the development of the maxilla; which may create a midfacial deficiency as well as an interference of the facial growth pattern and dentofacial esthetics. Objective: This study aimed to estimate the chronological age of complete fusion of the spheno-occipital synchondrosis (SOS) in cleft lip and palate patients and a control group; using cone beam computed tomography (CBCT) images. Methods: In this retrospective study; 125 patients were enrolled (cleft lip and palate group (n = 91); control group (n = 34)). Age comparison was made with a chi-square test; and a Kaplan–Meier analysis determined the median time to reach complete fusion of the spheno-occipital synchondrosis (p < 0.05). Results: The experimental group showed statistically significant differences in the median time for complete ossification between males and females (p = 0.019). The median time for complete ossification of the spheno-occipital synchondrosis was; for males; 15.0 years in both groups; for females; it was 14.0 years and 13.0 years in the experimental group and in the control group; respectively. Both for males and females; there were no statistically significant differences between experimental and control groups (p = 0.104). Conclusions: The present study showed no differences in the ossification of the spheno-occipital synchondrosis between individuals with and without cleft lip and/or palate.

Dentomaxillofacial CBCT: Clinical Challenges for Indication-oriented Imaging

This critical review discusses the clinical challenges for patient-specific and indication-oriented dentomaxillofacial cone beam computed tomography (CBCT). Large variations among units and protocols may lead to variable degrees of diagnostic and three-dimensional model accuracy, impacting both specific diagnostic tasks and treatment planning. Particular indications, whether diagnostic or therapeutic, may give rise to very specific challenges with regard to CBCT unit and parameter setup, considering the required image quality, segmentation accuracy, and artifact level. Considering that dental materials are in the field of view needed for diagnosis or treatment planning, artifact expression is a dominant factor in proper CBCT selection. The heterogeneity of dental CBCT units and performances may highly impact the scientific results. Thus research findings cannot be simply generalized as published evidence, and a demonstrated clinical applicability for a specific indication should not be simply extrapolated from one CBCT unit to another.

Interventions for impacted maxillary canines: A systematic review of the relationship between initial canine position and treatment outcome

BACKGROUND

The objective of this review was to critically assess the existing literature on the relationship between the initial position of impacted canines and treatment outcomes.

METHODS

We performed a systematic review of the available literature until February 2020 using the MEDLINE, Cochrane Central, Web of Science and PubMed databases. Prospective and retrospective studies (randomized controlled trials [RCTs], cohort studies, longitudinal follow-up studies) considering impacted maxillary canines that were orthodontically and/or surgically treated, and clearly reporting the initial position using 2D and/or 3D classifications, were included if they assessed at least one of the following: treatment success, treatment duration, number of treatment visits, radiographic outcome, periodontal health, esthetics and/or treatment complications. The included studies were assessed for risk of bias according to the Cochrane guidelines.

RESULTS

Seventeen studies were reviewed (2 RCTs and 15 non-RCTs). The included studies enrolled a total of 1247 patients with an average age of 14.1 years and a total of 1597 impacted canines. Various causal relationships were detected between the success of treatment modalities and the initial state of the impacted canine (bucco-palatal position, vertical position, canine angulation, root development).

DISCUSSION

Evidence, though limited, suggests that a higher alpha angle, higher vertical position and more mesial sector of the impacted canine are related to less successful interceptive and active treatment solutions, prolonged treatment time and inferior outcomes.

Periodontal implications of surgical-orthodontic treatment of an impacted dilacerated maxillary incisor: A case report with a 2-year follow-up

The treatment of an 8-year-old girl with a dilacerated maxillary incisor began in the mixed dentition; a modified palatal arch attached to the molars served as anchorage for the forced eruption of the dilacerated tooth to prevent the intrusion of the adjacent teeth and reduce the risk of root resorption. Two surgical sessions were planned: the first to permit the closed eruption; the second was an apically positioned flap to add attached gingiva to the labial side of the erupting tooth. The result was an optimal periodontal outcome; moreover, the roots of the adjacent teeth did not show any sign of resorption at the end of the forced eruption. The tooth was vital at the end of the treatment, and the apex covered by alveolar mucosa. The root developed normally throughout the treatment, and the periodontium was healthy and esthetically acceptable at the 2-year follow-up. Further study is needed to assess the advantages of the combined surgical-orthodontic treatment.

Alveolar Bone Segmentation in Intraoral Ultrasonographs with Machine Learning

The use of intraoral ultrasound imaging has received great attention recently due to the benefits of being a portable and low-cost imaging solution for initial and continuing care that is noninvasive and free of ionizing radiation. Alveolar bone is an important structure in the periodontal apparatus to support the tooth. Accurate assessment of alveolar bone level is essential for periodontal diagnosis. However, interpretation of alveolar bone structure in ultrasound images is a challenge for clinicians. This work is aimed at automatically segmenting alveolar bone and locating the alveolar crest via a machine learning (ML) approach for intraoral ultrasound images. Three convolutional neural network–based ML methods were trained, validated, and tested with 700, 200, and 200 images, respectively. To improve the robustness of the ML algorithms, a data augmentation approach was introduced, where 2100 additional images were synthesized through vertical and horizontal shifting as well as horizontal flipping during the training process. Quantitative evaluations of 200 images, as compared with an expert clinician, showed that the best ML approach yielded an average Dice score of 85.3%, sensitivity of 88.5%, and specificity of 99.8%, and identified the alveolar crest with a mean difference of 0.20 mm and excellent reliability (intraclass correlation coefficient ≥0.98) in less than a second. This work demonstrated the potential use of ML to assist general dentists and specialists in the visualization of alveolar bone in ultrasound images.

Quantification of DNA Double Strand Breaks and Oxidation Response in Children and Adults Undergoing Dental CBCT Scan

Assessing the possible biological effects of exposure to low doses of ionizing radiation (IR) is one of the prime challenges in radiation protection, especially in medical imaging. Today, radiobiological data on cone beam CT (CBCT) related biological effects are scarce. In children and adults, the induction of DNA double strand breaks (DSBs) in buccal mucosa cells and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and antioxidant capacity in saliva samples after CBCT examination were examined. No DNA DSBs induction was observed in children nor adults. In children only, an increase in 8-oxo-dG levels was observed 30 minutes after CBCT. At the same time an increase in antioxidant capacity was observed in children, whereas a decrease was observed in adults. Our data indicate that children and adults react differently to IR doses associated with CBCT. Fully understanding these differences could lead to an optimal use of CBCT in different age categories as well as improved radiation protection guidelines.

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.