Journal of the World Federation of Orthodontists最新文献

Background: The assessment of growth stages, typically determined by Cervical Vertebrae Maturation (CVM), plays a crucial role in orthodontics. However, there is a potential deviation from actual growth stages when using CVM. This study aimed to introduce CDSNet, an interpretable deep learning model for assessing growth stages based on cervical vertebrae, dentition, and frontal sinus in lateral cephalograms.

Methods: A dataset of 1,732 pairs of lateral cephalograms and hand-wrist radiographs from patients who underwent orthodontic treatment was annotated by four dentists. Benchmarks were conducted using CVM and logistic regression. Experiments were designed to evaluate CDSNet's performance in assessing growth stages using various methods and anatomical regions.

Results: CDSNet achieved remarkable Accuracy (90.99%), Precision (89.98%), Recall (92.50%), and F-1 Score (91.22%) in assessing growth spurt, representing significant improvements of 26.56%, 27.96%, 30.26%, and 29.30% compared to the CVM-based method. Additionally, when compared to a deep learning method based on cervical vertebrae, improvements of 12.25%, 11.40%, 14.14%, and 12.56% were observed. The interpretable module's side output revealed the involvement of cervical vertebrae, dentition, and frontal sinus in assessing growth spurt.

Conclusions: In the clinical domain, CDSNet is able to assist clinicians in determining patients' growth stages, particularly those near the boundary between two stages with less distinct features. This study demonstrated the role of interpretable deep learning in investigating the external manifestations of craniofacial growth. Integrating algorithmic or clinical research to analyze multiple features on lateral cephalograms proved a feasible approach to assist orthodontists and improve diagnostic efficacy.

Background: Using miniscrews to control anchorage made the application of force for various orthodontic treatment approaches easier and increased their effectiveness. Some problems may occur during the use of miniscrews, such as peri‑implant mucositis, mobility, postoperative pain, and failure. This study compared the success rate of miniscrews coated with chlorhexidine hexametaphosphate antimicrobial nanoparticles with that of uncoated miniscrews.

Methods: In a double-blind randomized controlled clinical trial using a split-mouth design, 80 miniscrews were inserted symmetrically into 40 individuals between the maxillary second premolar and first molar. Random allocation software was used to distribute the coated and uncoated miniscrews. The patients were monitored monthly, for a duration of 4 months. The main measure of interest was the success rate of miniscrews, which was assessed throughout follow-up periods of up to 4 months. The secondary objective was the assessment of the mobility of the miniscrews, peri‑implant health, and pain perception. A Wilcoxon signed-rank test and Kaplan-Meier survival analysis were applied to analyze the data.

Results: Main outcome: After the 4-month follow-up, the success rates of the miniscrews for coated and uncoated samples were 81.3% and 84.4%, respectively, which was a statistically insignificant difference.

Secondary outcome: Mobility and peri‑implant health were not statistically different between the coated and uncoated miniscrew groups. Pain intensity was rated higher on the first day, then decreased gradually, diminishing completely on the sixth and seventh day. However, the pain perception between the coated and uncoated miniscrews did not differ statistically.

Conclusions: Chlorhexidine-hexametaphosphate nanoparticles did not increase the success rate and stability, nor did they enhance peri‑implant health or affect pain perception during the short observation period.

Trial registration: This trial was registered at ClinicalTrials.gov; ID: NCT06124235.

This case report describes the successful orthodontic management of a 25-year-old female patient presenting with Class II Division 2 malocclusion, moderate maxillary anterior crowding, and a missing mandibular left first molar. Treatment plan involved extraction of two maxillary first premolars to address crowding and protraction of two mandibular left molars, combined with the strategic use of mini-implants for precise tooth movement control. Ridge-split surgery was adopted to manage alveolar ridge resorption in the edentulous area. This procedure was essential for widening the narrow alveolar ridge, thereby reducing resistance and facilitating the mesial movement of two mandibular left molars. Lingual and labial biomechanics, including linguoincisal elastics and a cantilever system, were utilized to optimize torque control and molar protraction. Clear aligners were employed throughout the treatment phases, navigating challenges such as the closure of extraction spaces and achieving stable buccal interdigitation. The treatment spanned 4 years, using a total of 175 aligners. The initial phase required 66 aligners to close maxillary extraction spaces and the mandibular edentulous space, followed by 52 aligners in the first refinement and 57 aligners in the second refinement phase. Posttreatment evaluations demonstrated successful alignment of dental arches, correction of malocclusion, and enhancement of facial aesthetics. This case highlights the efficacy of integrated orthodontic techniques in achieving comprehensive functional and aesthetic outcomes in complex orthodontic cases.

Introduction: Advancements in technology have led to the adoption of digital workflows in dentistry, which require the segmentation of regions of interest from cone-beam computed tomography (CBCT) scans. These segmentations assist in diagnosis, treatment planning, and research. However, manual segmentation is an expensive and labor-intensive process. Therefore, automated methods, such as convolutional neural networks (CNNs), provide a more efficient way to generate segmentations from CBCT scans.

Methods: A three-dimensional UNet-based CNN model, utilizing the Medical Image Segmentation CNN framework, was used for training and generating predictions from CBCT scans. A dataset of 351 CBCT scans, with ground-truth labels created through manual segmentation using AI-assisted segmentation software, was prepared. Data preprocessing, augmentation, and model training were performed, and the performance of the proposed CNN model was analyzed.

Results: The CNN model achieved high accuracy in segmenting maxillary and mandibular teeth from CBCT scans, with average Dice Similarity Coefficient values of 91.83% and 91.35% for maxillary and mandibular teeth, respectively. Performance metrics, including Intersection over Union, precision, and recall, further confirmed the model's effectiveness.

Conclusions: The study demonstrates the efficacy of the three-dimensional UNet-based CNN model within the Medical Image Segmentation CNN framework for automated segmentation of maxillary and mandibular dentition from CBCT scans. Automated segmentation using CNNs has the potential to deliver accurate and efficient results, offering a significant advantage over traditional segmentation methods.

Background: While orthodontic miniscrews have been widely documented for their successful application, limited research exists on the stability and effectiveness of reused miniscrews. This systematic review aims to evaluate the stability and effectiveness of reused miniscrews in orthodontic treatments.

Methods: An electronic search was conducted for studies published up to February 2024 across MEDLINE, Web of Science, EMBASE, Scopus, and Cochrane CENTRAL. Additionally, gray literature sources and manual searches of prominent orthodontic journals from 2010 to 2023, were also examined. Studies that investigated the use of miniscrews after retrieval and sterilization involving both in vitro studies and clinical trials were included.

Results: From 946 searched studies, 18 were finally included in our review. Thirteen studies investigated retrieved and sterilized miniscrews, while five examined unused and sterilized miniscrews to isolate the effects of sterilization. After performing a meta-analysis on in vitro studies, no significant difference in insertion, removal, or fracture torque between retrieved and unretrieved miniscrews was found, though sterilized miniscrews had a statistically significant increase in insertion torque without affecting fracture resistance. Meta-analysis of clinical studies revealed that retrieved miniscrews exhibited a significantly higher failure rate with a risk ratio of 0.46 (95% confidence interval = 0.24, 0.69), indicating a higher likelihood of failure on reuse.

Conclusion: There were no significant differences in insertion and fracture torque between new and reused miniscrews. However, reused miniscrews were associated with a higher failure rate. This outcome may be influenced by factors such as sterilization methods, insertion technique, and patient-specific anatomical considerations.

Background: This study used cone-beam computed tomography (CBCT) via voxel-based superimposition to evaluate lip and incisor changes after orthodontic treatment with four premolar extractions (Ext) versus nonextraction (Non-Ext) among African American (AA) and White (W) patients.

Methods: A total of 240 CBCTs of 120 adolescent orthodontic patients with Class I skeletal/dental relationships were included. Patients were initially divided according to treatment, and then each group was subdivided according to patients' ethnicity (Ext/W = 30, Ext/AA = 30, Non-Ext/W = 30, and Non-Ext/AA = 30). CBCTs were imported into Invivo6 for voxel-based superimposition. Lip and incisor measurements were recorded. Independent t tests and two-way ANOVA were used for statistical assessment.

Results: The Non-Ext/W group had a greater increase in all outcome variables compared with the Non-Ext/AA group, with a significant change in volume and position of upper (UL) and lower lips (LL), inclination of upper (U1) and lower incisors (L1), and position of U1. The Ext/AA group had a greater decrease in all measured outcomes compared with the Ext/W group, with significant change in inclination of U1 and L1, and position and volume of LL. W patients had more crowding than AA patients in both treatment approaches. Retraction ratios of 6.5:1 and 2.1:1 were recorded between the U1 and UL positions, and L1 and LL positions, respectively. There were no direct interaction effects between ethnicity and treatment, nor were there any significant effects of ethnicity after controlling for the covariates.

Conclusions: Ethnicity alone has no impact on incisor and lip position after treatment. However, ethnicity in the form of initial presentation of malocclusion can have a significant influence.

Background: Non-invasive restoration of tooth enamel is a topic of high relevance in dental material science. Multiple approaches have been proposed to reach optimum reconstruction results. The current study was performed to evaluate the cross-sectional microhardness besides mineral quality and content in artificially induced carious enamel after treatment with hydroxyapatite-chitosan (HAp-CS) nanocomposite gel.

Methods: Artificially carious lesions were induced by immersion of teeth in acidic carboxymethyl cellulose gel (pH 4.95-5) for 24- and 72-hours periods. Two different compositions of HAp-CS nanocomposite hydrogel were prepared with two different ratios 50/50 (%) and 70/30 (%), respectively. Additionally, sodium fluoride gel (1000 ppm concentration) was prepared and used as reference. Gels were applied to carious lesions twice/day for 3 min/each. After 45 days of application, surface morphology, energy dispersive x-ray spectroscopy, micro-Raman analysis in addition to cross-sectional microhardness were evaluated. Statistical analysis was performed using two-way ANOVA and Tukey's post hoc statistical tests.

Results: Surface morphological evaluation of treated surfaces showed obliteration of surface irregularities. Groups demineralized for 24 hours and treated with 70/30 (HAp-CS) showed highest significant cross-sectional-microhardness (P ≤ 0.05). Evaluated subsurface cross-sectional microhardness showed better mineral quality for groups demineralized for 24 hours and treated with HAp-CS nanocomposite gels.

Conclusions: Nanocomposite gel with 70/30 (HAp-CS) could efficiently improve cross-sectional microhardness and both minerals composition and quality for lesions demineralized for 24 hours. More severely induced lesions, as demineralized for 72 hours, need more powerful agent compositions and/or prolonged application protocols for improvement.