Progress in Orthodontics最新文献

Background: The symbiotic relationship between the oral microbiome and the host immune system is a prerequisite of oral health. Disruptions to this system can be associated with the development of diseases like dental caries. Introducing orthodontic treatments, such as aligners and fixed appliances, might impact this microbial ecosystem. This study evaluated potential changes in salivary microbiome and the level of inflammatory marker myeloid-related protein 8/14 in patients undergoing orthodontic treatment with aligners or fixed appliances.

Methods: Forty-eight patients were divided into two groups for treatment with fixed appliances or clear aligners. Unstimulated saliva samples were collected at baseline, three, and six months for microbiome analysis via 16 S rRNA sequencing and MRP-8/14 level measurement using ELISA.

Results: Among 503 identified microbial species, no significant changes were noted in overall microbiome. A considerable increase of caries-relevant species could not be observed either. MRP-8/14 levels remained unchanged across treatments, indicating no alterations in the inflammatory level.

Conclusion: Orthodontic treatment with fixed or removable appliances does not significantly alter the salivary microbiome or influence inflammation, suggesting that these interventions are unlikely to affect oral health negatively.

Background: The mechanical properties of directly 3D-printed clear dental aligners are currently constrained by the limitations of available 3D printing materials. This study aimed to investigate the mechanical properties of direct 3D-printed clear resin embedded with orthodontic wire under different surface treatments to propose a novel integration method for orthodontic appliances and treatment.

Methods: The stainless-steel wires were divided into three groups based on surface treatments: control groups (C), sandblasting group (S), sandblasting and acid etching group (SA). Surface characteristics were analyzed and interfacial shear strength (IFSS) was measured. Dumbbell-shaped specimens were fabricated using 3D-printed clear resin and divided into four groups, depending on whether they were embedded with stainless-steel wires subjected to different surface treatments. The static and dynamic mechanical properties tests were carried out to calculate elastic modulus, tensile strength, and stress relaxation.

Results: The average roughness and surface morphology of stainless-steel wires exhibited significant differences (P < 0.001) following different surface treatments. Sandblasting and acid-etching significantly enhanced IFSS, resulting in a fivefold increase to 28.8 MPa. The elastic modulus and tensile strength of the 3D-printed resin embedded with wires were significantly higher than those of the pure 3D-printed resin group. However, no significant differences in elastic modulus were observed among the different wire surface treatment groups. The sandblasting and acid-etching group exhibited higher residual stress compared to the other groups during both 6-hour and cyclic stress relaxation tests.

Conclusion: This study presents a novel approach to 3D-printed clear dental aligners integrated with metal wires for orthodontic treatment. Surface treatment of orthodontic metal wire through sandblasting and acid etching enhances the bonding strength between the wire and 3D-printed clear resin, improving the static and dynamic mechanical properties of directly 3D-printed clear resin appliances. The innovative process and device provide an integrated solution for digital orthodontic treatments.

Introduction: Achieving a harmonious soft tissue profile and enhancing facial appearance are key goals of early treatment for skeletal class III malocclusion.

Aim: To summarize the current evidence regarding the effects of Class III orthodontic treatment on facial soft tissues, and to compare various Class III orthodontic appliances.

Methods: A comprehensive search was conducted up to July 2024, using seven databases, with no language restrictions. RCTs and controlled non-randomized studies were included in this systematic review. The GRADE framework was applied to evaluate the quality of evidence.

Results: Thirty studies were included in this review, of which sixteen were appropriate for quantitative synthesis. The age range fell between 6.6 and 12.3 years. The FM/RME protocol resulted in a 1.58 mm increase in upper lip protrusion and a 4.73-degree decrease in the nasolabial angle compared to the control group. Chincup treatment led to a 2.13 mm increase in upper lip protrusion and a 2.63 mm decrease in lower lip protrusion compared to the control group. The pooled estimate demonstrated a significant increase of 1.82 mm in upper lip protrusion, a significant retrusion of 3.14 mm in the lower lip, and a backward movement of the chin by 4.8 mm in patients treated with miniplate-anchored orthopaedic facemask (FM/MP) compared to the untreated group. However, no significant difference was found between FM/RME and FM/MP, except for a noticeable decrease in the nasolabial angle in the FM/RME group. The analysis of FM/Alt-RAMEC versus FM/RME did not reveal any difference in soft tissue outcomes, except for the upper lip protrusion. The Alt-RAMEC group showed a more pronounced anterior movement of the upper lip by 0.67 mm compared to the RME group. The quality of evidence supporting these findings ranged from low to moderate.

Conclusions: There is low to moderate evidence suggesting that early treatment positively influences the soft tissues in Class III patients. However, these conclusions are based on a two-dimensional analysis of cephalometric images, which may not provide complete or accurate information. Therefore, more RCTs using comprehensive 3D analysis are needed to confirm these results.

Registration: PROSPERO ( CRD42024517924 ).

Background: During the process of intruding the mandibular anterior teeth (MAT) with clear aligners (CA), the teeth are susceptible to undesigned buccal and lingual inclinations, leading to complications such as excessive alveolar bone resorption and root exposure that significantly compromise the treatment outcome. Therefore, it is imperative to investigate the underlying causes and develop effective coping strategies.

Methods: We first statistically analyzed the clinical issues, then used FEA to explore their underlying mechanisms to guide the design of attachments in clinical practice. Specifically, CBCT data before and after the intrusion treatment of MAT were collected to analyze the labial-lingual inclination of the MAT and the distance between the root apex and alveolar bone wall. Finite element analysis (FEA) models of MAT undergoing vertical intrusion with standard CA were created with eight incisor mandibular plane angles (IMPA) to assess displacement trends, labial and lingual moments, and crown contact forces. Additionally, six aligner attachments were designed to simulate and analyze their biomechanical mechanisms.

Results: Significant differences were observed in changes before and after treatment. When the IMPA was 90°, the crown experienced a labial moment. The labial root control ridge (RCR) increased the labial moment of the crown, while the lingual RCR and labial attachment (LA) increased the lingual moment. The lingual fossa excavating holes (LFEH) group also increased the labial moment. The lingual RCR enhanced the lingual movement of the crown, whereas the LFEH promoted labial movement. During the intrusion of MAT, a comprehensive design incorporating labial intrusive attachments, labial RCR, lingual RCR, and LFEH can be employed to ensure true vertical intrusion of the lower anterior teeth.

Conclusion: This study revealed the biomechanical changes during intrusion, and innovatively designed the LFEH, thereby promoting the development of novel orthodontic techniques and improving clinical treatment outcomes.

Background: To establish consensus of skeletal anchorage versus conventional anchorage in treating: 1. Maxillary transverse deficiency in growing and adult patients, 2. Class II skeletal disharmony due to mandibular retrusion in growing patients, 3. Class III skeletal disharmony in growing patients.

Methods: A four-rounds modified Delphi method was conducted. A steering committee performed a literature selection and compiled a list of 33 statements. An international panel of 25 experts in orthodontics agreed to participate. In each round, panelists were asked to rate their level of agreement with each statement using a 5-point Likert scale and provide comments. Statements that reached consensus were either accepted or rephrased. Statements that did not reach consensus were either rephrased, rejected, or split into two statements or merged with another.

Results: After the four rounds, 24 statements achieved consensus while 9 were rejected. The distribution of consensus statements was as follows: Maxillary transverse deficiency: 4 statements; Class II skeletal disharmony: 10 statements; Class III skeletal disharmony: 10 statements.

Conclusions: This modified Delphi consensus study aimed to provide guidance for orthodontists in choosing between skeletal and conventional anchorage for various treatment conditions. The study generated 24 consensus statements across three key domains. While the Delphi method provides valuable expert opinions, future studies, including randomized controlled trials, are needed to confirm these findings and address remaining uncertainties. Such efforts will aid in refining orthodontic treatment protocols and enhancing patient outcomes.

Background: Orthodontically induced root resorption (OIRR) is a common side effect of orthodontic treatment. This study compares the degree of OIRR between root-filled teeth (RFT) and vital pulp teeth (VPT), and analyzes relevant study variables.

Methods: We conducted a retrospective study on 69 patients who had undergone orthodontic treatment. Using Cone-beam computed tomography (CBCT), we measured changes of root length before and after treatment through a unique method involving three-dimensional (3D) image registration and superimposition. Factors related to the OIRR such as gender, type of treatment, tooth type, age, duration of treatment and distance of root movement were considered.

Results: The sample included 55 females and 14 males aged 27.19 ± 6.08 years. On the basis that there was no significant difference in the root movement distance between RFT and VPT, RFT showed significantly less OIRR than VPT (P < 0.05). Gender did not significantly impact on OIRR for either RFT or VPT group (P > 0.05). In women specifically, RFT displayed less resorption than VPT (P < 0.05). For treatment type, extraction cases demonstrated a lower degree of OIRR in RFT than VPT (P < 0.05), and notable greater OIRR in with-extraction group compared to no-extractions group was found in RFT (P < 0.05), but not in VPT (P > 0.05). Tooth type did not yield significant differences in OIRR overall; however, upper teeth and premolars experienced lower resorption in RFT than in VPT (P < 0.05). Cases treated with fixed appliance had higher OIRR in both RFT and VPT than those with clear aligners (P < 0.05). Age did not correlate significantly with OIRR for either group (P > 0.05). And duration of treatment positively correlated with OIRR for both types (RFT: r = 0.5506, P < 0.0001; VPT: r = 0.4371, P = 0.0002), so did root movement distance (RFT: r = 0.2955, P = 0.0140; VPT: r = 0.2790, P = 0.0206).

Conclusions: RFT exhibit significantly less OIRR than VPT after orthodontic treatment. Treatment type, appliance type, duration of treatment and root movement distance are significant factors influencing OIRR. Personalized orthodontic treatment plans and vigilant monitoring are crucial to mitigate OIRR risks.

Background: Primary failure of eruption (PFE) is a rare disorder characterized by a posterior open bite. While mutations in the parathyroid hormone 1 receptor (PTH1R) gene have been demonstrated to cause PFE, the underlying mechanisms remain largely unknown.

Methods: Whole exome sequencing was conducted to identify PTH1R variants in a PFE family. MG63 cells that stably expressed the corresponding mutant PTH1R were established using lentiviruses. Next, osteogenesis was assessed by measuring cell alkaline phosphatase activity, conducting alizarin red staining, and evaluating osteoblast-specific gene expression. Then, computational analysis of binding affinity and RNA sequencing were carried out. Lastly, rescue experiments were performed to validate the mechanism underlying the pathogenesis of PFE.

Results: A novel PTH1R missense mutation (c.904G > A, p.E302K) was identified in a Chinese family affected by PFE. Moreover, the E302K mutation inhibited the expression of osteogenic-specific genes and proteins in MG63 cells. Computational analysis revealed the E302K mutation decreased the binding affinity of Gα_s to the PTH1R protein. Consistently, cAMP accumulation assays demonstrated that the E302K mutation impaired the intracellular PTH_1-34 -induced accumulation of cAMP. Further RNA sequencing analysis and validation experiments revealed that the PI3K-AKT signaling pathway was predominantly down-regulated in response to the E302K mutation. Finally, forskolin partially restored the effects of the E302K mutation on osteogenesis.

Conclusions: This study indicated that the E302K mutation in PTH1R decreased the binding affinity of PTH1R protein for Gα_s, down-regulated the cAMP-PI3K/AKT signaling pathway, and inhibited osteogenesis, eventually leading to PFE. This study not only expands the genotypic spectrum of PTH1R mutations but also elucidates the underlying pathogenic mechanism of PTH1R-associated PFE.

Objective: This study aims to evaluate the incidence of open gingival embrasures (OGES) after orthodontic treatment and analyze its correlation with various clinical and radiographic parameters.

Methods: We retrospectively analyzed 330 orthodontic patients at West China Hospital of Stomatology from 2016 to 2023, categorizing them into Non-OGES (200) and OGES (130) groups based on post-treatment OGES presence in the central incisor area. Basic information of patients, pre- and post-treatment lateral cephalometric radiographs, and cone-beam computed tomography (CBCT) data were collected. Chi-square tests, two-sample t-tests, Welch's t-tests, and Mann-Whitney U tests were used to compare differences in gender, initial age, treatment duration, and cephalometric and CBCT indicators between the two groups. Binary logistic regression analysis was further employed to explore the clinical characteristics and cephalometric indicators of the study population.

Results: Univariate analysis revealed that the occurrence of maxillary central incisor OGES was significantly correlated with gender, initial age, treatment duration, and related cephalometric and CBCT indicators (P < 0.05). Similarly, the occurrence of mandibular central incisor OGES was also significantly associated with gender, initial age, treatment duration, and specific cephalometric changes (P < 0.05). Binary logistic regression analysis indicated that the occurrence of maxillary central incisor OGES was significantly related to initial age, treatment duration, and the change in the U1-SN angle, while the occurrence of OGES in the mandibular central incisor area was mainly related to initial age and treatment duration.

Conclusion: Orthodontic treatment plans should consider a variety of influencing factors, including initial age, treatment duration, anterior tooth angle and position, root-bone relationship, and the distance from the anterior tooth contact point to the alveolar crest, to prevent or reduce the occurrence of OGES after orthodontic treatment, thereby improving patients' aesthetic outcomes and periodontal health.

Background: Mid-palatal placement of temporary skeletal anchorage devices (TSADs) has become increasingly popular among clinicians due to high success rates, low associated risk and streamlining and enhanced customization of associated supra-structures. There is however limited patient data in relation to associated experiences and impacts.

Methods: A survey of patients undergoing mid-palatal TSAD insertion was undertaken using a 27-item bespoke questionnaire. Questionnaires were sent using both electronic and surface mail with a 3-month period allowed for response. Pain experience; the use of analgesia; requirement for additional visits; impacts on hygiene, speech, eating, and hobbies; and social impacts were assessed. Reponses involved the use of a Visual Analogue Scale as well as binary information.

Results: Overall, 152 responses were obtained with 87.5% describing experience of TSAD insertion either "as expected" or "better". Procedural pain was reported as mild in 62.5%. Local post-operative pain was scored as moderate in 21.1%. Some functional impairment was reported with 63.2% attributing difficulty with speech and 67.8% difficulty with eating due to the implant. However, these functional impairments were generally considered mild (by 68.1% and 60.2%, respectively) and most were very likely to recommend this treatment to others, with 65.1% (n = 99) scoring 8 or above out of 10.

Conclusions: Appreciable levels of pain, discomfort and functional impairment were noted with the use of mid-palatal TSADs. However, any unpleasant experiences were generally regarded as mild with most highly likely to recommend mid-palatal TSADs to prospective patients.

Objective: This study aimed to evaluate the positional and morphological changes in the temporomandibular joint (TMJ) in adult patients with skeletal Class I malocclusion treated with fixed orthodontic appliances (FAs) and clear aligners (CAs), both with and without premolar extractions.

Methods: This retrospective study involved 120 adult patients divided into non-extraction and extraction groups, each further subdivided equally into those treated with FAs and CAs. Cone beam computed tomography (CBCT) was used to assess the TMJ measurements before (T0) and after treatment (T1). Statistical analyses were conducted to compare the mean changes in intra- and inter-groups. A significance level of p ≤ 0.05 was considered.

Results: In the non-extraction group, specifically in FAs, significant increases were observed in TMJ parameters; anteroposterior condylar position (APCP) and mediolateral condylar inclination (MCI). Conversely, significant decreases were noted in vertical condylar position (VCP) and vertical condylar inclination (VCI). In the extraction group, significant increases were noted in APCP and anterior joint space (AJS), while posterior joint space (PJS) and anteroposterior condylar joint position (APCJP) decreased. For inter-group comparisons, the extraction group showed significant increases in APCP in FAs compared to CAs, and a significant decrease in APCJP in FAs compared to CAs.

Conclusion: FAs significantly impact condylar positions and joint spaces, especially in extraction cases. Monitoring TMJ parameters during orthodontic treatment is crucial to ensure positive outcomes and prevent TMJ disorders (TMDs). These findings may guide the selection of orthodontic appliances based on individual malocclusion characteristics.