Progress in Orthodontics最新文献

Objective: To develop a machine-learning-based model and construct a nomogram that integrates ClinCheck features and clinical risk factors for accurately predicting open gingival embrasures (OGE) between mandibular central incisors after clear aligner treatment (CAT).

Methods: A total of 297 patients (163 normal and 134 with OGE) who underwent Invisalign^® treatment were enrolled. A ClinCheck model was developed based on predicted OGE-area in the final step from initial ClinCheck treatment plan. Twenty-three clinical features were extracted from electronic medical records and ClinCheck tooth movement metrics. Predictors were selected through Least Absolute Shrinkage and Selection Operator (LASSO) regression to establish a clinical model. Additionally, a nomogram incorporating ClinCheck features and clinical predictors was constructed via logistic regression and validated with bootstrap resampling. The performances of these models were evaluated through receiver operating characteristic (ROC) curves, area under curves (AUC), and decision curve analyses (DCA).

Results: Six clinical features, including age, gingival papilla angle, interproximal reduction, crown morphology and two types of tooth movement, were selected through LASSO regression. The combined model that consisted of OGE-area and clinical features demonstrated superior predictive capacity (AUC: 0.880; 95% CI: 0.840-0.916), outperforming both clinical model (AUC: 0.815; 95% CI: 0.767-0.861; P < 0.001) and ClinCheck model (AUC: 0.860; 95% CI: 0.817-0.900; P < 0.05). The corrected C-statistic of the combined nomogram was 0.888, and the calibration curve exhibited great performance with a mean absolute error of 0.012. In the DCA curve, the combined model showed higher net benefit than the clinical model when the threshold probability exceeded 0.13, and higher than the ClinCheck model between 0.13 and 0.63.

Conclusion: The integration of clinical features and ClinCheck in the machine-learning-based model demonstrated favorable predictive capabilities for OGE between lower central incisors. This comprehensive nomogram may contribute to precisely prediction and prevention of OGE in clinical practice.

Background: A deep bite is a prevalent malocclusion, and its treatment remains one of the most debated topics in orthodontics due to the variety of underlying causes and the diverse orthodontic approaches employed to address it.

Objective: This systematic review aimed to assess the evidence on the most effective approach for treating deep bites in adult and adolescent patients.

Search methods: A thorough search was performed up to January 2025 among these databases: PubMed^®, the Cochrane Library, Scopus^®, Web of Science™, Embase^®, and Google™ Scholar.

Selection criteria: Only randomized controlled trials (RCTs) were included in this review on adult and adolescent patients with deep bite malocclusion who underwent any orthodontic treatment to correct this malocclusion.

Data collection and analysis: The Cochrane tool (ROB2) was employed to assess the risk of bias, while the GRADE approach was used to evaluate the quality of evidence.

Results: Eight RCTs were included in this review. Five of the eight studies were suitable for qualitatively synthesizing the data. The meta-analysis showed that the miniscrew-supported intrusion (MSI) caused a statistically significant amount of overbite reduction (mean difference (MD) = - 0.36 mm), upper incisor intrusion (MD = - 0.77 mm), and upper incisor proclination (MD = 0.63^o) compared to the Connecticut intrusion arch (CIA), and the quality of evidence was low to moderate. Moderate-quality evidence indicated that there was no statistically significant difference between the anterior bite turbos (ABT) and the lower reversed curve of Spee (RCS) regarding overbite reduction (MD= - 4.07 mm, MD = - 3.27 mm, respectively). A low-quality evidence indicated that the MSI and the utility arch (UA) caused more overbite reduction than the J-Hook headgear (J-Hg) (MD = -2.33 mm, MD = - 2 mm, MD = - 0.8 mm, respectively). However, the MSI was superior regarding upper incisor intrusion than the UA and the J-Hg (MD = - 2.08 mm, MD = - 1.33 mm, MD= - 0.1 mm, respectively).

Conclusion: Low-quality evidence suggests that MSI is superior to CIA for reducing overbite, and causing more upper incisor proclination. Moderate -quality evidence indicates that MSI is superior to CIA for intruding the upper incisors. Moderate-quality evidence indicates that the ABT and the RCS effectively reduce overbite. Low-quality evidence suggests that the MSI and the UA cause more overbite reduction and upper incisor intrusion than the J-Hook headgear, and the MSI causes more upper incisor intrusion than the UA.

Registration: The protocol was registered in the PROSPERO database (CRD42025633739) during the first stages of the review.

Objective: This retrospective clinical study, using cone-beam computed tomography (CBCT), examined the presence of fenestration and dehiscence in anterior teeth following non-extraction clear aligner therapy, along with the associated risk factors.

Methods: The study included 224 adult patients who underwent non-extraction clear aligner treatment. CBCT scans taken before (T1) and after treatment (T2) were analyzed to detect the presence of fenestration and dehiscence. Patient-related and treatment design-related variables were collected, with the latter from the planned tooth movements specified in the aligner software. The exact McNemar test was used to compare the occurrence of alveolar bone defects between T1 and T2. Univariate and multivariate logistic regression analyses were performed to evaluate the associations between posttreatment alveolar bone defects and various factors.

Results: From T1 to T2, the occurrence of fenestration and dehiscence increased on most maxillary and mandibular anterior root surfaces. At T2, the presence of alveolar bone defects at different tooth positions was influenced by multiple factors, including crowding, curve of Spee depth, alveolar bone thickness, gingival thickness, sagittal skeletal pattern, magnitude and type of intrusion, amount of retraction, molar distalization, and number of attachments. Specifically, labial fenestration of the maxillary lateral incisors and canines, as well as the mandibular central incisors and canines, and lingual dehiscence of the mandibular central incisors were significantly associated with the amount of intrusion (P < 0.05). Labial dehiscence of the mandibular central and lateral incisors was significantly associated with the number of attachments (P < 0.05). No significant associations were found between alveolar bone defects and factors such as age, gender, vertical skeletal pattern, changes in arch width, use of miniscrews, the amount of interproximal enamel reduction, attachment type, or treatment duration.

Conclusions: In patients undergoing non-extraction clear aligner therapy, factors such as crowding, curve of Spee depth, alveolar bone thickness, gingival thickness, sagittal skeletal pattern, amount and type of intrusion, amount of retraction, molar distalization, and number of attachments were significantly associated with the presence of fenestration and dehiscence at T2. Orthodontists should assess these factors, conduct thorough pretreatment evaluations of individual oral conditions, and develop tailored treatment plans accordingly.

Background: It is generally accepted that the ideal time to benefit from functional therapy in Class II patients is during the circumpubertal growth period (CVM 3-4). However, in severe cases, early intervention during the mixed dentition phase may be indicated, particularly to reduce the risk of dental trauma and to protect the child from potential bullying. The aim of this study was to evaluate the effects of the Manni Telescopic Herbst (MTH) appliance in young patients with mixed dentition, comparing the outcomes with two control groups: one treated with Class II elastics and a Wilson arch, and the other with a removable functional appliance (Paolone-Kaitsas, PK).

Methods: Following statistical matching for age, sex and pre-treatment overjet, lateral cephalograms taken at beginning (T0) and at appliance removal (T1) from 30 patients treated with the MTH appliance were compared with those of 15 patients treated with Class II elastics and 15 treated with the PK appliance.

Results: Regarding skeletal parameters, significant differences were observed in the mandibular sagittal position (SNB (T1-T0), p = 0.01) and in the relationships between skeletal bases (ANB (T1-T0), p = 0.03; Wits (T1-T0), p < 0.01), when comparing MTH and PK groups to the Class II elastics group. The Herbst group exhibited the most substantial skeletal changes. For dental variables, better incisor control was achieved with the removable PK appliance (Ii/GoGn T1-T0 1.513 ± 5.739, and Is/PP (T1-T0) 2.507 ± 6.482). No statistically significant difference was found regarding skeletal divergence (SN/GoGn (T1-T0), p = 0.38) when focusing on younger patients in mixed dentition phase.

Conclusion: Both the fixed MTH appliance and the removable PK appliance produced greater skeletal effects compared to Class II intermaxillary elastics, even when applied during the mixed dentition phase. Although the PK group demonstrated better dentoalveolar control, when significant skeletal modifications are required in young patients with mixed dentition, the use of a fixed functional appliance - such as the Herbst - is preferable.

Background: This study aimed to screen favorable and unfavorable profile outcomes in orthodontic camouflage treatment of skeletal Class II cases, based on which to identify the reference line and the associated value for the optimal incisor position objective (IPO) in such cases.

Methods: A total of 140 Chinese adult skeletal Class II cases were included, who finished orthodontic camouflage treatment with anterior retraction following premolars extraction. Post-treatment lateral cephalograms were trimmed and converted into silhouettes, rated by a panel of orthodontists. The top 30% and bottom 30% ranked cases were included as the favorable and unfavorable profile group respectively. The distances of U1 anterior to the GALL line (U1-GALL), point A vertical (U1-Av), and ANS-Pog line (U1-ANPo) were measured as IPO indicators.

Results: U1-ANPo in the favorable profile group was 4.74 ± 1.65 mm, significantly different from that in the unfavorable profile group (6.02 ± 3.61 mm). U1-GALL was -2.68 ± 2.30 mm and -1.12 ± 2.02 mm, and U1-Av was 4.49 ± 3.97 mm and 6.22 ± 4.42 mm, in the favorable and unfavorable profile group respectively, neither showing significant difference. Among three indicators, only U1-ANPo had a significant discriminatory capacity (AUC = 0.74, P = 0.007) for differentiating between the favorable and unfavorable profile group.

Conclusions: In skeletal Class II orthodontic camouflage treatment, the relatively favorable post-treatment profiles are associated with the U1 position anterior to the ANS-Pog line. U1-ANPo of around 4.7 mm could be tentatively proposed as a practical IPO reference in treatment planning for such cases.

Primary failure of eruption (PFE) is an uncommon autosomal dominant disorder predominantly defined by an impaired tooth eruption mechanism. It is characterized by a unilateral or bilateral open bite in the posterior area and incomplete or absent tooth eruption. Nonetheless, its etiology remains unclear. Current studies indicate that PFE may be directly associated with mutations in several genes, including parathyroid hormone receptor 1 (PTH1R), lysine (K)-specific methyltransferase 2 C (KMT2C), and transmembrane protein 119 (TMEM119). Despite the growing research on PFE genetics, no cohesive conceptual framework exists to integrate the known genetic information. This review seeks to address this gap and introduce a novel pathogenic model. The model posits that the normal eruption of teeth relies on the precise equilibrium between "The Pro-Eruptive Axis" and "The Anti-Resistance Axis," with the Dental Follicle (DF) serving as the central regulatory hub of this mechanism. This research will systematically categorize PFE-related genes and classify their pathogenic mechanisms as "insufficient motivation" or "excessive resistance" in eruption. On this basis, this review will analyze in depth the crosstalk of key signaling pathways (such as PTH, Wnt, TGF-β, and RANKL/OPG), investigate the complexity of genetic influences and temporal factors in elucidating phenotypic variability, enhance the existing classification framework into a dynamic, multi-dimensional comprehensive network, and ultimately suggest precise diagnostic approaches and prospective therapeutic targets based on pathogenic mechanisms from a translational medicine perspective. By constructing this integrated pathophysiological model, we aim to establish a robust theoretical framework for investigating molecular mechanisms and clinical diagnosis and formulating novel individualized treatment options for PFE.

Background: Clear aligners face biomechanical limitations in complex tooth movements, particularly first molar mesialization, despite attachment use. Finite element analysis (FEA) can elucidate optimal attachment designs for force delivery.

Objectives: To compare displacement patterns and stress distribution during maxillary first molar mesialization using four attachment designs via 3D FEA.

Methods: A maxillary model (MRI-derived) was created with periodontal ligament (PDL), alveolar bone, and clear aligner (0.75 mm thickness). Five scenarios were simulated: no attachment (Model-I), vertical rectangular (Model-II), horizontal rectangular (Model-III), optimized double semi-ellipsoidal (Model-IV), and Yin-Yang attachments (Model-V). Mesial displacement (0.5 mm) was applied, and deformation/stress were analyzed using ANSYS Workbench.

Results: Model-IV (optimized attachment) demonstrated the least first molar tipping, evidenced by its lowest total mesial crown displacement (0.319 mm), and provided the best mesiodistal control. Conversely, Model-I (no attachment) exhibited the highest tipping, with a total mesial crown displacement of 0.376 mm. Yin-Yang attachments (Model-V) significantly reduced buccal displacement by 92% compared to Model-I. Horizontal rectangular attachments minimized rotational movement.

Conclusions: Optimized double semi-ellipsoidal attachments provide superior first molar mesialization control, while Yin-Yang designs enhance buccal-lingual stability. Attachment geometry critically influences aligner efficacy.

The "periodontal ligament-periosteum (PDL-PS) sandwich hypothesis" has been proposed to explain the mechanism of bone recovery around roots moved outside their bony housing. This hypothesis suggests that the presence of the periosteum and periodontal ligament facilitates bone recovery in such cases. This retrospective case series examines three adult patients who developed iatrogenic dehiscences and fenestrations of the anterior teeth due to the placement of fixed lingual retainers after orthodontic treatment. Each patient then underwent orthodontic retreatment aimed at repositioning the roots back into the alveolar housing. Cone-beam computed tomography (CBCT) scans and intraoral photographs taken before (T2) and after (T3) retreatment were used to evaluate bone recovery. To test the PDL-PS sandwich hypothesis, predictions of bone recovery were made based on T2 parameters and the root movements achieved during retreatment. The observed bony recovery at T3 was then compared with these predictions. Roots that were partially or fully repositioned into the original alveolar housing exhibited partial to complete bony recovery. In contrast, teeth with minimal root movement back into bone showed limited or no recovery. In cases with pre-existing gingival recession, bone recovery occurred only apical to the areas of recession, even with favorable root movements. Additionally, the dimensions of the alveolar housing remained stable as roots moved through the alveolar bone, supporting the theory that roots move through alveolar bone, rather than with bone, in adults. These findings highlight the need for evidence-based clinical strategies to guide the management of inadvertent tooth movement caused by orthodontic appliances or retainers, with particular attention to the potential for bone recovery when repositioning teeth into their original alveolar housing.

Background: Maxillary expansion has been a treatment of choice for correcting transverse skeletal discrepancies, especially in growing patients. For older patients, Mini-implant Assisted Rapid Palatal Expansion (MARPE) offers a promising treatment option. This study evaluates the treatment outcomes of Custom 3D-printed MARPE compared to Conventional MARPE (MSE-II).

Methods: This retrospective study analyzed CBCT images from 42 patients aged 16 to 35 years, comparing measurements before (T1) and after (T2) expansion. The conventional (n = 21) and custom (n = 21) MARPE groups were matched with age and sex. Skeletal and dental changes were evaluated measuring twelve distances and four angles using Dolphin Imaging Software (Chatsworth, Calif). The measurements included frontozygomatic and maxillary widths, nasal cavity width, and dentoalveolar inclination. The effectiveness of each appliance was evaluated based on magnitude of expansion and successful correction of transverse discrepancy.

Results: The custom MARPE group demonstrated comparable or greater increase in width across various anatomical landmarks to the conventional group. Logistic regression suggested a trend toward higher odds of successful transverse discrepancy correction with custom MARPE.

Conclusions: Custom 3D-printed MARPE appliances may offer advantages in achieving skeletal expansion in older patients. Individualized appliance design and strategic mini-implant placement could contribute to effective treatment. However, further research is needed to evaluate long-term outcomes, cost-effectiveness, and potential complications to better guide appliance selection for each patient.