Orthodontics & Craniofacial Research最新文献

Objectives: This study aims to determine the effect of gelatin-simvastatin hydrogel application on bone remodelling during relapse.

Materials and methods: Twenty-four rabbits (Oryctolagus cuniculus) were divided into a control group (n = 12) and a treatment group (n = 12). The lower incisors were subjected to orthodontic force and moved distally by an open coil spring. The force (50 cN) was extended for 1 week and retained in a new position for 2 weeks (stabilisation period). The treatment group received a local gelatin-simvastatin hydrogel administration during stabilisation, and the control group received only gelatin hydrogel. The springs were debonded after the stabilisation phase from both groups to facilitate a relapse. The percentage of relapse was measured in a model study using digital callipers. Levels of OPG and RANKL were analysed using ELISA.

Results: The local application of gelatin-simvastatin hydrogel in the treatment group significantly decreases the relapse percentage and RANKL level. Additionally, the gelatin-simvastatin hydrogel significantly increases the level of OPG and ratio of OPG/RANKL.

Conclusions: Applying gelatin-simvastatin hydrogel in the retention period can induce bone formation, inhibit orthodontic relapse and increase tooth stability (in vivo).

Objective: In Class II elastics treatment, the mandible is subject to sustained protraction. The study aimed to investigate the morphological and histological changes resulting from sustained mandibular protraction, through establishment of a novel model in rat.

Materials and methods: Forty-eight 4-week-old male Sprague-Dawley rats were randomly divided into three groups, including the 50 and 100 cN protraction groups, and the control. In the two protraction groups, NiTi coil springs were fixed between the metal bands on the maxillary incisors and mandibular molars to pull the mandible forward. CBCT scans were taken immediately before (T0), 2 weeks (T1) and 4 weeks (T2) after the traction. Histological and immunohistochemical analyses were performed at T1 and T2.

Results: Increase of the condylar process length and angular process length were significantly larger in the two protraction groups than that in the control; however, the condylar process angle (∠CPA) was significantly reduced by the protraction at T2, leading to decreased condylar height. The protraction decreased the condylar cartilage thickness at T1, which recovered to the control level at T2, with no significant changes detected in the expression of SRY-related high mobility group-box gene 9 (SOX9) and type II collagen (COL II), two chondrogenic markers.

Conclusion: The established rat model is manoeuvrable and reliable, which exerts sustained and measurable mandibular protraction. The sustained protraction increases the lengthening of the mandibular condylar process, but alters its growth direction by causing it to turn downwards.

Introduction: Upper airway obstruction (UAO) management in children, particularly those with associated anatomical mid-face structural differences, poses a significant challenge. This study describes using a nasopharyngeal airway (NPA) in managing infants with severe upper airway obstruction.

Methods: Infants discharged home from Queensland Children's Hospital with an NPA in situ for the management of upper airway obstruction were retrospectively evaluated for clinical and demographic parameters, underlying diagnoses and respiratory support, including NPA insertion details and comorbidities.

Results: Sixty-seven children (24 male) were included with a median age at NPA insertion of 24 (IQR 7-59) days and a median duration of NPA use of 229.1 (IQR 151.50-297.75) days. Fifty-two (77.6%) had Pierre Robin sequence. Other diagnoses included CHARGE syndrome, Treacher Collins syndrome, Stickler syndrome, Crouzon syndrome, Bohring-Opitz syndrome, isolated cleft palate, Beckwith-Wiedemann syndrome, Chromosome 3 deletion and VACTERL association. Four infants required tracheostomy, and no complications related to NPA use were reported. Those with oximetry and polysomnography data showed improving indices following NPA insertion [pre NPA median (IQR) SpO₂: 95.9% (94.73-97.73), AHI: 51.40 (44.50-69.45), OAHI 65.9 (56.45-73.35) and TcCO₂ (mmHg) 65.70 (61.95-67.30) vs. post-NPA median (IQR) SpO₂: 97.1% (96.19-97.9), AHI: 12.20 (11.25-24.35), OAHI 10.20 (6.12-5.62) and TcCO₂ (mmHg) 52.40 (47.90-58.40)].

Conclusion: Our findings highlight the effectiveness and safety of NPA as a noninvasive management option for severe upper airway obstruction in children, particularly in those with anatomical midface structural differences. Further research and larger studies are warranted to confirm these findings and optimise management strategies for these patients.

Objectives: This study aimed to assess the efficacy of active presurgical orthopaedics appliances in infants presenting with complete unilateral cleft lip and overlapped alveolus (T-shaped alveolus).

Materials and methods: A retrospective and prospective longitudinal study was performed. Infants diagnosed with complete unilateral cleft lip and overlapped alveolus, received treatment with the active presurgical orthopaedics appliances from June 2020 to June 2023, at Children's Hospital 1, Ho Chi Minh City. The treatment duration averaged 3 months. Pre- and posttreatment casts of noses and alveolus were scanned using TRIOS3 Wireless intraoral scanner (3Shape, Denmark) and analysed with Slicer 5.2.2 software. There were 16 quantitative variables. A pair t-test and Wilcoxon signed ranks were used for analysis. The statistical significance was adopted as p < 0.05.

Results: A total 40 patients (17 males, 23 females, mean age 23.85 ± 19.22 days) were evaluated. After treatment, the nostril height increased by 2.62 ± 0.22 mm and the deviation columella decreased by -23.45° ± 2.29°. There was a reduction in cleft gap (-3.77 ± 2.01 mm), and in the overlap of alveolus (-3.71 ± 1.83 mm), the growth of cleft segment increased by 2.27 ± 2.00 mm, while the rotation of the noncleft side alveolus decreased by -5.29° ± 5.31°. The changes were statistically significant (p < 0.001).

Conclusions: Active presurgical orthopaedics appliances improved the nasal deformity and overlapped alveolus morphology in infants with complete unilateral cleft lip and T-shaped alveolus.

The objective of the present systematic review and meta-analysis was to assess the effectiveness of clear aligner therapy (CAT) for the treatment of anterior open bite (AOB) in adults. The focused question was "Is CAT effective for the management of AOB in adults?". Databases were searched without time and language barriers up to and including August 2024 based on pre-specified eligibility criteria. Risk of Bias (RoB) assessment was performed using the Risk-of-Bias-In-Non-randomised-Studies-of-Intervention (ROBINS-I) tool. Meta-analyses were conducted using a random effects model (REM) for change in AOB and cephalometric measurements with an evaluation of the mean difference (MD) and/or standardised mean difference (SMD). The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) tool was used to assess the quality of evidence. Publication bias was assessed using Funnel plots and Egger's regression test. There were 14 studies included in the qualitative assessment and 12 in the meta-analysis. The RoB was moderate in 13 studies and low in one. The meta-analysis showed significant AOB correction with CAT [(MD) = 2.76 mm, 95% confidence interval (CI): 2.23-3.28] due to maxillary and mandibular incisor extrusion (MD = 0.85 mm, CI: 0.43-1.26 and MD = 0.86 mm, CI: 0.29-1.44, respectively). There were no significant changes identified for maxillary and mandibular molar intrusion or changes in the mandibular plane angle (MPA). The level of confidence was high for AOB correction, incisor extrusion, and molar intrusion and low for MPA. CAT leads to a significant correction of AOB of approximately 2.76 mm, which can be mainly attributed to incisor extrusion.

Objective: Although the technique of orthodontic aligners has risen in popularity, their mechanical properties have not been thoroughly investigated. The aim of this study was to evaluate the mechanical properties of the orthodontic aligners Clear Aligner after intraoral use for 7, 10 and 14 days, and to compare them with as-received aligners (0 days). It was also sought to examine the properties of the unprocessed raw material (polyethylene glycol terephthalate) used to manufacture these aligners.

Materials/methods: Thirty-two aligners by four patients were evaluated and studied at 0, 7, 10, 14 days of use. Each aligner was divided into three segments (two posterior and one anterior), which resulted in 96 samples. Also, 16 samples of unprocessed material were studied. For all samples, elastic modulus, ultimate tensile stress (UTS) and yield stress were calculated by conducting tensile testing. Additionally, material hardness was tested. The two-tailed Mann-Whitney test was performed, having set the level of significance at p = 0.05.

Results: Analysis of the measurements indicated a statistically significant decrease in elastic modulus between days 0 and 14 of use, of UTS between days 0 and 7, 7 and 10, and of yield stress between days 0 and 7. For hardness, in every period, posterior segments demonstrated significantly higher values than anterior segments. All properties of the unprocessed material were statistically significantly higher than the processed samples.

Conclusions: The unprocessed material presented significant differences in every property tested in comparison to the processed aligners. The processed material showed further deterioration over time during use. The present study provides evidence that thermoforming and ageing affect the mechanical properties of the aligners.

Objectives: To explore orthodontists' (OTs) and paediatric dentists' (PDs) practices and perceptions regarding the screening and management of paediatric obstructive sleep apnea (OSA).

Methods: This explanatory sequential mixed methods design included OTs and PDs with active clinical practice in Brazil and encompassed a quantitative phase followed by a qualitative phase. In the quantitative phase, a survey assessing OSA screening and management practices was administered to OTs and PDs practicing in Brazil. Information-rich OTs and PDs were interviewed in the qualitative phase. Descriptive statistics and the chi-square test were used to analyse the survey data, while inductive content analysis was applied to the interview data. The results from both phases were integrated and reported narratively.

Results: Three hundred eighty-one OTs and PDs completed the survey, and ten of them were interviewed. Nearly half of OTs and PDs administered sleep questionnaires and demonstrated some knowledge about paediatric OSA signs and symptoms. PDs and OTs primarily offered rapid maxillary expansion and functional mandibular advancement for managing selected children with OSA, with OTs being more frequently involved in this task than PDs. OTs and PDs identified several barriers and expressed the need for support regarding access to reliable screening tools and interprofessional care.

Conclusion: Brazilian OTs and PDs were aware of the main signs and symptoms of paediatric OSA and were somewhat involved in offering oral appliance management options. To further define the role of these professionals, increasing support for dental professionals in OSA management and updating existing clinical guidelines is warranted.

Objective: To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion.

Materials and methods: An in vitro orthodontic force tester (OFT) was used to measure the forces and moments from a typodont where the buccal teeth were translated lingually 0.2 mm to simulate expansion. Hemi-ellipsoid and rectangular attachments with either 0.5 or 1.0 mm thickness were added on upper right first premolar (UR4), second premolar (UR5) and first molar (UR6). Analysis of variance (ANOVA) was used to determine two-way interactions among the factors on the outcomes.

Results: The interactions between group and tooth were significant for all outcomes (p < 0.001). The greatest buccal forces (Fy) were observed with 1 mm rectangular attachment on the UR4 (0.78 ± 0.29 N), with 1 mm hemi-ellipsoid attachment on UR5 (0.28 ± 0.21 N) and with 0.5 mm rectangular attachment on UR6 (1.71 ± 0.18 N). The greatest buccolingual moments (Mx) were obtained with 1 mm rectangular attachment on UR4 (5.61 ± 1.43 Nmm), without any attachments on UR5 (3.33 ± 1.73 Nmm) and with 1 mm hemi-ellipsoid attachment on UR6 (4.18 ± 4.31).

Conclusion: Direct attachment shape and size had a significant effect on the orthodontic forces and moments generated by thermoplastic aligners during simulated expansion. Although loads varied significantly by tooth morphology and its location in the arch, best forces and moments for expansion were obtained with 1 mm rectangular attachments on UR4s, 1 mm hemi-ellipsoid attachments on UR5s and 0.5 mm rectangular attachments on UR6s.

During orthodontic treatment, undesirable reciprocal forces are generated during tooth movement, which explains the use of anchorage strategies to minimise their harmful effects through intra and/or extraoral appliances. Miniscrews are intraoral devices used for temporary skeletal anchorage. Miniscrews are small-sized intraoral devices used for temporary skeletal anchorage and are easy to place and remove. However, some studies refer to adverse effects such as inflammation, pain, and discomfort. This systematic review aims to synthesise the available evidence on the use of miniscrews during orthodontic treatment from the patient's perspective. The literature search was conducted using various databases MedLine through PubMed, Cochrane Library, Web of Science Core Collection, and EMBASE. A search was also carried out in the grey literature. The search terms used were "Orthodontic Anchorage Procedures," "mini-implant," "Mini Dental Implant," "Miniscrew," and "microimplant." Cochrane risk of bias tools was used to assess the quality of included studies. Patients tend to overestimate the pain inherent in this procedure. The insertion of micro implants is more accepted than the tooth extraction procedure, with less postoperative pain reported. The location, surgical technique, and type of anaesthesia used in the placement of miniscrews influence levels of discomfort. Additionally, the execution of a good surgical technique and the clinician's communication skills are factors that influence patient satisfaction and positive perception. The most frequent outcome reported is pain and discomfort, which varies depending on its location (less with mini interradicular screws than with extra-alveolar screws). Most patients are satisfied or very satisfied with this application.

Objectives: Oral appliance (OA) has been increasingly used for the treatment of obstructive sleep apnoea hypopnea syndrome (OSAHS). OAs work by propelling the mandible, increasing the upper airway calibre and reducing collapsibility. While they have shown efficacy in reducing OSAHS, long-term use can lead to adverse effects, such as dental displacement. The present study focuses on the impact on dental displacements of the NARVAL® computer-aided design and manufacturing OA from the ResMed laboratory.

Materials and methods: The study included 39 patients aged 18 or older who were treated for OSAHS using OAs initiated between 2019 and 2021 and had initial digital dental impressions. A new digital print was taken for each patient using the TRIOS 4 Wireless intra-oral scanner from 3SHAPE. Dental displacement was measured using a 3D system's GEOMAGIC design X 3D reverse engineering software. The study analysed different blocks of teeth in both the maxillary and mandibular arches. Statistical analysis was conducted to determine the significance of dental displacements.

Results: Patients had been wearing the OA for an average of 2.5 years. The study found dental displacements in both the maxillary and mandibular arches. However, these displacements were not statistically significant. Qualitative analysis revealed palatoversion and vestibuloversion, while quantitative analysis showed minor dental displacements.

Conclusion: This study on patients wearing the NARVAL® OA for an average of 2.5 years found dental displacements in both the maxillary and mandibular arches. However, these displacements were not statistically significant. The results suggest that the OA, designed using a complete digital workflow, did not significantly impact dental positions. To confirm the impact, further investigations with larger sample sizes, an exclusively digital protocol and a control group are required.