Orthodontics & Craniofacial Research最新文献

Objective: Few studies have analysed the outcome of bone grafts in bilateral alveolar clefts and the bone fill with a two-step surgery method. The currently applied three-dimensional method used in this study enables a comprehensive description of the bone fill of bilateral clefts after bone grafting. The study aimed to describe alveolar cleft volume and bone fill after alveolar bone grafting of bilateral alveolar clefts treated with two-step bone grafting, with a comparison between the first and the second bone graft site. A secondary aim was to investigate whether the cleft volume on the non-surgical side changed after contralateral surgery.

Materials and methods: In this retrospective study, 60 CBCT scans from 20 patients were included (8 girls and 12 boys) with an age range of 6.5-11.5 years (mean age 8.7). The cleft volume was measured in pre- and post-operative CBCT scans and assessed in ITK-SNAP to calculate the bone fill of the cleft.

Results: After bone grafting, 47% of the first bone-grafted cleft was filled with bone, and 33% of the second bone-grafted cleft, without significant difference between them (p = 0.03). The mean preoperative cleft volume was 0.42cm³ and the mean residual cleft volume after bone graft was 0.23cm³. There was however a significant difference when comparing the bone fill between the nasal and the dental part (p < 0.001).

Conclusion: Almost half of the cleft volume was filled with bone after bone grafting. The order of the bone graft side did not influence the bone fill of the cleft.

Objectives: The objectives are to assess the severity and frequency of clinically relevant external apical root resorption (EARR) ≥ 2 mm during orthodontic treatment with Damon passive self-ligating and Victory conventional standardised fixed appliance systems and to evaluate the relevance of intermediate radiographic examinations for early detection and prevention of severe EARR.

Materials and methods: Adolescents aged 12-17 years with crowded and displaced teeth planned for non-extraction treatment were recruited from three orthodontic clinics. Participants were randomly allocated in a 1:1 ratio to treatment with either Damon Q (n = 35) or Victory (n = 40) using stratified blocks, with allocation concealed. EARR was assessed for all roots from incisors to molars using multiplanar reconstruction in cone beam computed tomography (CBCT) images acquired from various CBCT machines before, during and after treatment.

Results: Sixty-two patients were included in the EARR analysis. The upper incisors were the most affected tooth group, with mean EARR values of 0.20 mm for Damon and 0.51 mm for Victory (NS, alpha 1%). The frequency of clinically relevant EARR in this tooth group was 5.0% for Damon and 7.2% for Victory (NS, alpha 5%). Only one case with clinically relevant EARR after treatment was identified in the intermediate radiographic examinations.

Conclusions: The overall severity and frequency of EARR were below clinically relevant levels in both treatment groups. The results strengthen the evidence that routine intermediate radiography appears to be of limited relevance for early detection and prevention of severe EARR in non-extraction treatments for adolescents with crowded teeth.

Trial registration: ClinicalTrials.gov: NCT05664282.

Objective: Primary aim was to analyse dentoalveolar and skeletal effects induced by an anterior open bite (AOB) treatment protocol for intrusion of maxillary buccal segment. Secondary aim was to investigate whether a subsequent change occurred in hyoid position.

Materials and methods: Study group included 28 non-growing subjects treated in academic setting for correction of AOB. All patients received same appliance that included bilateral acrylic bite-blocks covering posterior dentition. Intrusive force was applied between buccal bars of appliance and zygomatic multipurpose implants. Lateral cephalograms taken at pre-treatment (T0) and after intrusion (T1) were analysed using NemoCeph software. Eight skeletal, 9 dental, 6 soft tissue and 5 hyoid parameters were measured and evaluated statistically.

Results: Mean open bite was -3.2 ± 2.1 mm at T0. T1-T0 duration was 9.6 ± 1.9 months. Increase in SNB (1.1° ± 2.1°) and the decrease in ANB (-1.1° ± 1.3°), Y-axis (-0.5° ± 3.5°), SN-GoGn (-2.0° ± -2.5°) and lower facial height (-1.4 ± 2.1 mm) were significant, indicating mandibular counter-clockwise rotation. Overjet and open bite decreased significantly (-1.8 ± 2.3 mm and 4.2 ± 2.1 mm, respectively). Maxillary molars intruded (U6-PP: -3.1 ± 1.3 mm) and distalised (ΔU6-TVL: -1.5 ± 2.7 mm) significantly. Mean change in L6-MP was significant (0.9 ± 1.4 mm) showing mandibular molar eruption. Lower lip-true vertical line (TVL) showed significant forward movement of lower lip (-1.8 ± 2.3 mm). Mean changes in hyoid parameters were not significant.

Conclusion: Significant maxillary buccal segment intrusion was achieved in a relatively short period. AOB was corrected while facial profile and smile aesthetics were improved. Distalisation of maxillary molar suggests that intrusive force vector can be modified to achieve simultaneous intrusion and distalisation.

Objectives: This study aimed to evaluate and compare the antibacterial properties and optical characteristics of clear orthodontic aligners coated with zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles.

Materials and methods: In this experimental laboratory study, polyethylene terephthalate glycol (PETG) aligner samples were coated with nanoparticles of ZnO, MgO and a combination of both (ZnO + MgO). The surface coatings were analysed before and after stability testing using field emission scanning electron microscopy (FESEM). Colour changes and translucency were measured using a spectrophotometer, and the antimicrobial and antibiofilm properties were evaluated against Streptococcus mutans and Lactobacillus species. Statistical analysis was conducted using SPSS, with significance set at p < 0.05.

Results: Significant statistical differences were found in the colour changes between the groups (p < 0.001), with the greatest change in MgO-coated aligners (0.94 ± 0.09), followed by ZnO + MgO (0.75 ± 0.05) and ZnO (0.5 ± 0.09). ZnO-coated aligners exhibited the highest translucency (47.6 ± 0.44) compared to MgO (45.07 ± 0.74) and ZnO + MgO (45.76 ± 0.7) (p = 0.002 and p = 0.026, respectively). Nanoparticle-coated aligners showed significantly reduced bacterial growth (p < 0.05). The ZnO + MgO combination demonstrated superior antibacterial effects compared to individual coatings. Nanoparticles remained stable after 24-h agitation in artificial saliva and brushing, maintaining 60%-65% stability.

Conclusion: The aligners coated with ZnO nanoparticles exhibited the least colour change and the highest translucency compared to those coated with MgO nanoparticles and the ZnO + MgO combination. The highest antibacterial properties were observed in the aligners coated with a combination of ZnO and MgO nanoparticles.

Objectives: This non-randomised clinical study aimed to identify the phenotypic characteristics that distinguish responders from non-responders. Additionally, it sought to establish a predictive model for treatment response to obstructive sleep apnoea (OSA) using mandibular advancement devices (MAD), based on the analysed phenotypic characteristics.

Material and methods: This study, registered under identifier NCT05596825, prospectively analysed MAD treatment over 6 years using two-piece adjustable appliances according to a standardised protocol. Two response definitions aligned with the latest International Consensus Statement on OSA severity were established. Logistic regression and CHAID models integrated baseline clinical, anthropometric, cephalometric anatomical, soft tissue characteristics and physiological upper airway variables.

Results: A total of 112 patients completed the study: 64 responders and 48 non-responders according to response definition 1, and 81 responders and 31 non-responders according to response definition 2. Responders to MAD treatment had lower body mass index (BMI), neck and waist circumference, Epworth Sleepiness Scale scores, apnoea-hypopnea index (AHI), snoring intensity on the Visual Analog Scale, CPAP pressure, and higher T90% and minSaO₂. Patients exhibiting greater anatomical imbalance, smaller airway volume, smaller minimum cross-sectional area (CSAmin) and longer airway length demonstrated a poorer response to treatment.

Conclusions: Airway length, initial T90% and anterior facial height collectively formed a highly predictive logistic regression model for response definition 1. Jarabak's ratio, gonial angle, CSAmin, airway length, initial BMI and baseline AHI constituted a highly predictive model for the second response definition. Furthermore, the CHAID regression tree established cutoff values for the variables that form the predictive models.

Background: Orthodontic treatment need has commonly been assessed using treatment need indices during clinical examinations or using photographs in combination with plaster casts. Recently, the use of intraoral photographs alone to screen malocclusions has increased.

Objective: This study aimed to validate intraoral photographs for the assessment of orthodontic treatment need.

Materials and methods: The study sample consisted of case files from 30 pre-orthodontic patients aged 12-19 years. Each case file included intraoral photographs and casts. The cases were consecutively recruited from two orthodontic treatment waiting lists: 15 from the Department of Orthodontics at Folktandvården Eastmaninstitutet, Stockholm, Sweden and 15 from the Center for Orthodontics and Pediatric Dentistry, Norrköping, Public Dental Service Östergötland. Their orthodontic treatment need was assessed by four raters (calibrated orthodontists) using the indices IOTN-AC, IOTN-DHC, ICON, and DAI. The four raters individually assessed the 30 cases on three occasions: (1) photos only, (2) photos and casts, and (3) photos only. Finally, the four raters jointly made a consensus assessment using both photos and casts. For IOTN-AC and IOTN-DHC, interrater agreement was assessed with Fleiss' kappa, and validity with the Wilcoxon signed-rank test. For ICON and DAI, interrater agreement was assessed with Intra Class Correlation (ICC) (1, 2) and validity with a paired t-test.

Results: Interrater agreement for IOTN-AC was slight (0.14-0.18) and moderate for IOTN-DHC (0.51-0.57), regardless of whether photographs were used alone or combined with casts. ICON demonstrated moderate interrater agreement (0.57-0.72), while DAI showed moderate to excellent (0.70-0.91), similarly unaffected by the use of photographs alone or in combination with casts. The validity analysis, which compared the individual assessments to the consensus one, revealed equivalent differences whether the assessment involved intraoral photographs alone or in combination with casts.

Conclusion: Intraoral photographs are sufficient for assessing orthodontic treatment need because interrater agreement and validity are similar whether photos are used alone or with casts. However, interrater variability was substantial for both assessment methods.

Trial registration: ClinicalTrial.gov. identifier: NCT05038865.

Objectives: Radiographs are routinely acquired for orthodontic evaluation, and incidental findings (IFs) may be detected early as part of this routine care. This study aimed to assess the prevalence of IFs on panoramic radiographs taken for orthodontic assessment and evaluate the ability of orthodontists to detect, interpret and recommend management for IFs.

Materials and methods: A retrospective analysis of 1756 patients aged 7-21 with a panoramic image taken for orthodontic evaluation was performed. IFs were categorised by anatomic region and assigned a significance level based on a custom-made risk assessment tool. Twelve selected images were evaluated by 30 orthodontists via a standardised online survey. Participants were tasked with reviewing each image, providing a radiological interpretation, and indicating whether a referral would be needed prior to commencing orthodontic treatment. The responses were scored against those of an expert oral and maxillofacial radiologist (OMFR). Inter-observer agreement was evaluated by computing the Cohen's K.

Results: The prevalence of IFs was 30.8%. The most common findings were impacted teeth (17.7%), hypodontia (14.9%) and dense bone islands (14.7%). After applying the risk assessment tool, 35% of the findings were considered highly significant. The overall agreement between the orthodontists and OMFR was k = 0.32 (95% CI = 0.30-0.34). The agreement for location was 0.52 (95% CI = 0.47-0.58), whereas it was k = 0.45 (95% CI = 0.40-0.50) for diagnosis and k = 0.19 (95% CI = 0.13-0.24) for referral need.

Conclusions: Orthodontists may benefit from additional education and training focused on interpretation and management of IFs on panoramic radiographs.

Objective: This retrospective study aims to assess the predictability of Overbite (OVB) reduction and Curve of Spee (COS) levelling in patients with deep bite malocclusion treated with Clear Aligner Therapy (CAT). The research evaluates the accuracy of the prescribed movements in growing and non-growing patients.

Materials and methods: Thirty-six patients treated with Invisalign from January 2018 using SmartTrack were included. Digital models at pre-treatment, virtual plan and post-treatment phases were collected and analysed using Geomagic Control X. Accuracy was assessed for COS levelling, OVB reduction and individual tooth movements. Statistical analyses included descriptive statistics, paired t-tests and linear regression between accuracy of the movements and the age of the patient.

Results: The study found that the prescribed movements in ClinCheck often overestimated the achieved outcomes. The mean accuracy for COS levelling was 62%, and for OVB reduction, it was 61%. No significant association was observed between the accuracy and the age of the patient.

Conclusion: Clear Aligner Therapy demonstrated moderate accuracy in achieving prescribed movements for COS levelling and OVB reduction. Clinicians should exercise caution in virtual treatment planning and may need to consider potential modifications to software projections to enhance desired outcomes. Further research comparing different aligner protocols and brands is warranted to advance understanding and improve treatment predictability.

Background: Different protocols exist regarding wear time of invisible aligners. There is no study that compared the effect of different protocols. The aim of this study was to assess the effect of Invisalign aligners in four first-premolar extraction treatments in adolescents using three aligner wear protocols, every 7, 10 and 14 days.

Materials and methods: In the experimental set-up, 50 participants were divided into three distinct groups: group A, with a regimen of changing aligners every 7 days; group B, with a 10-day interval for aligner replacement; and group C, where aligners were replaced every 14 days. The evaluation of occlusal adjustments was conducted employing the Discrepancy Index (DI) and the Cast-Radiograph Evaluation (CRE), as defined by the American Board of Orthodontics for the purpose of recording orthodontic outcomes. The treatment duration, number of maxillary and mandibular Invisalign aligners, and number of Invisalign restarts were simultaneously recorded and evaluated. The data set was statistically examined using ANOVA, complemented by the F-test, least significant difference (LSD) method and Tamhane's T2 test.

Results: The final sample size for analysis is 45 cases, with five cases lost to follow-up. Before treatment, the three groups showed no significant difference in the degree of malocclusion or each item of DI (p > 0.05). Posttreatment, within groups, and regardless of the wearing protocol, the total CRE scores demonstrated no statistically significant differences (p > 0.05). For the other items, groups A and C completed occlusal relations and interproximal contacts significantly better than did group B (p < 0.05). The group C cases had the least number of Invisalign refinement (3.93 ± 0.96 vs. 4.93 ± 0.70 vs. 6.00 ± 1.25, p < 0.05), but the treatment duration and number of Invisalign aligners were not significantly different (p > 0.05).

Conclusions: The different treatment timing protocols showed equivalent effectiveness regarding treatment outcome, with significantly improved results for the 7- and 14-day protocol in terms of occlusal relations and interproximal contacts. The attainment of comparable clinical accuracy between the 7- and 14-day protocol, within a treatment duration of fewer than 3 months, indicates that the 7-day protocol can be deemed an effective treatment approach.

Objective: This retrospective study aimed to evaluate morphometric changes in mandibular condyles of patients with skeletal Class III malocclusion following two-jaw orthognathic surgery planned using virtual surgical planning (VSP) and analysed with automated three-dimensional (3D) image analysis based on deep-learning techniques.

Materials and methods: Pre-operative (T1) and 12-18 months post-operative (T2) Cone-Beam Computed Tomography (CBCT) scans of 17 patients (mean age: 24.8 ± 3.5 years) were analysed using 3DSlicer software. Deep-learning algorithms automated CBCT orientation, registration, bone segmentation, and landmark identification. By utilising voxel-based superimposition of pre- and post-operative CBCT scans and shape correspondence, the overall changes in condylar morphology were assessed, with a focus on bone resorption and apposition at specific regions (superior, lateral and medial poles). The correlation between these modifications and the extent of actual condylar movements post-surgery was investigated. Statistical analysis was conducted with a significance level of α = 0.05.

Results: Overall condylar remodelling was minimal, with mean changes of < 1 mm. Small but statistically significant bone resorption occurred at the condylar superior articular surface, while bone apposition was primarily observed at the lateral pole. The bone apposition at the lateral pole and resorption at the superior articular surface were significantly correlated with medial condylar displacement (p < 0.05).

Conclusion: The automated 3D analysis revealed distinct patterns of condylar remodelling following orthognathic surgery in skeletal Class III patients, with minimal overall changes but significant regional variations. The correlation between condylar displacements and remodelling patterns highlights the need for precise pre-operative planning to optimise condylar positioning, potentially minimising harmful remodelling and enhancing stability.