Progress in Orthodontics最新文献

Background: To explore the potential role of cGAS-STING/GPX4 axis-mediated ferroptosis in cementoblast mineralization under compressive force and to determine its involvement in orthodontically induced inflammatory external root resorption (OIIERR).

Methodology: An immortalized murine cementoblast cell line (OCCM-30) was subjected to a 2 g/cm² compressive force for 24 h to establish an in vitro loading model. Western blot was used to detect proteins associated with mineralization (RUNX2, OPN, OCN) and components of the cGAS-STING/GPX4 axis. Ferroptosis was assessed by measuring ROS, Fe²⁺, and MDA levels. Mitochondrial damage was examined via mitochondrial membrane potential analysis and mtDNA linkage evaluation. To further investigate the role of cGAS-STING/GPX4 axis-mediated ferroptosis, STING knockdown and Ferrostatin-1 (Fer-1) were employed. In vivo, an OIIERR mouse model was established, and the STING inhibitor H-151 was administered to assess the involvement of cGAS-STING/GPX4 axis-mediated ferroptosis in OIIERR.

Results: Compressive force significantly reduced RUNX2, OPN, OCN, and GPX4 expression, while increasing ROS, Fe²⁺, and MDA levels. Mitochondrial dysfunction, including decreased membrane potential and cytoplasmic mtDNA leakage, was observed. Western blot analysis showed that compressive force significantly upregulated cGAS, p-STING, p-TBK1 and p-IRF3 in OCCM-30 cells. Knockdown of STING or Fer-1 treatment restored mineralization under compressive force. In vivo, immunohistochemical staining confirmed the activation of cGAS-STING/GPX4 axis in the OIIERR group. Notably, administration of H-151 reduced the expression of pathway-related proteins and effectively mitigated root resorption.

Conclusions: Compressive force inhibits cementoblast mineralization by inducing ferroptosis via the cGAS-STING/GPX4 axis. Furthermore, H-151 effectively suppresses OIIERR in mice. Targeting cGAS-STING/GPX4 axis-mediated ferroptosis may serve as a potential therapeutic strategy for OIIERR treatment.

Background: This study aimed to evaluate the effect of external force applied from mini-screws to the aligner during space closure in extraction cases, and to determine the optimal loading conditions to prevent lingual crown tipping of the incisor and mesial tipping of the molar using the finite element (FE) method.

Methodology: A three-dimensional FE model of the maxillary dentition with extraction of first premolars was constructed, and three different loading conditions were designed. The aligner was activated for 0.25 mm of incisor retraction without using mini-screws, with application of 0, 100, 200, or 300 cN of distal force through mini-screws placed in the posterior region, or with application of 0, 100, 200, 300, or 400 cN of intrusive force through mini-screws placed in the anterior region, in addition to the application of 300 cN of distal force.

Results: As the magnitude of distal force increased, the degree of mesial tipping of the first molar gradually decreased, becoming almost zero with nearly 300 cN of distal force. As the magnitude of intrusive force increased in addition to the application of 300 cN of distal force, the degree of lingual crown tipping of the central incisor gradually decreased, becoming almost zero with nearly 400 cN of intrusive force.

Conclusion: Application of 300 cN of distal force to the aligner from mini-screws placed in the posterior region could completely prevent mesial tipping of the molar and anchorage loss during anterior retraction. Application of 400 cN of intrusive force from mini-screws placed in the anterior region could prevent lingual crown tipping of the incisor, thus providing better torque control for the incisors.

Background: This study evaluated the fit and thickness of aligners at tooth embrasures, comparing three-dimensional (3D)-printed and thermoformed aligners.

Materials and methods: Thirty aligners-3D-printed (no-offset and 0.05 mm offset) and thermoformed-were fabricated and mounted on a maxillary dental model. All aligners were scanned using microcomputed tomography. Embrasure gap distance and thickness were measured at coronal and cervical levels, and ratios reflecting aligner fit and thickness changes after fabrication were calculated. The Kruskal-Wallis and Mann-Whitney U tests were used for group and vertical level comparisons.

Results: The 0.05 mm offset 3D-printed aligners exhibited significantly smaller embrasure gaps than the no-offset 3D-printed and thermoformed aligners, with no significant differences between coronal and cervical levels. The other groups showed larger gaps at the cervical level. The embrasure fit ratio was higher in the 0.05 mm offset 3D-printed group (73-93%) compared with the no-offset 3D-printed group (58-86%) and thermoformed group (44-85%). Thermoformed aligners demonstrated significant thickness reduction after fabrication, with ratios of 36.5-88.5% relative to the original sheet, whereas 3D-printed aligners exhibited significant thickness increases, with ratios of 197-470% relative to the virtual design.

Conclusions: The 0.05 mm offset 3D-printed aligners exhibited a superior fit compared with the no-offset 3D-printed and thermoformed aligners. The 3D-printed aligners showed significant thickness increases at embrasures, in contrast to the notable thickness reductions observed in thermoformed aligners.

Background: Clear aligner therapy is gaining traction owing to its esthetics and comfort. Although most aligners use thermoforming, 3D printing offers advantages such as higher accuracy and reduced waste. While literature on the properties of some 3D-printed aligner materials compared to thermoformed ones is available, a comprehensive study is currently lacking that compares all three materials (iLuxclear (LC), Graphy Clear Aligner (GY), and RightBio Clear Aligner (RD)) with thermoformed materials, particularly regarding optical and biofilm adhesion characteristics.

Methodology: Three 3D direct-printed materials (LC, GY and RD) and two thermoformed materials (easyDu (ED) and Biolon (SC)) were tested. Surface morphology was analyzed by stereomicroscopy. Surface roughness (Ra) was measured at baseline (0 day) and after 45 days of immersion in artificial saliva. Light transmittance and color stability (ΔE₀₀) were evaluated after 7 and 14 days of aging in saliva, black tea, and coffee. Bacterial adhesion was quantified using Streptococcus mutans (S. mutans) at baseline and after 3 and 7 days.

Results: The 3D direct-printed aligners, particularly the LC group, exhibited increased surface morphology irregularities and significantly higher Ra values than the thermoformed materials; Ra increased after 45 days of immersion in artificial saliva across all groups. The thermoformed materials maintained stable color integrity, while the 3D-direct printed materials varied in performance. GY demonstrated a uniform surface structure, lower roughness, and the highest color stability, whereas LC and RD experienced significant discoloration. The RD group exhibited significantly higher S. mutans adhesion, whereas the thermoformed materials exhibited superior biofilm resistance. Notably, GY achieved comparable S. mutans adhesion to the thermoformed materials after a 7-day culture.

Conclusions: Among the 3D direct printed aligners, GY achieved comparable surface and microbiological performance to conventional options. These findings underscore their potential for balancing esthetics, susceptibility to bacterial adhesion, and clinical performance in clear aligner therapy.

Objective: This study examined the relationship between smile aesthetics perception and personality factors among individuals with varying dental education backgrounds.

Materials and methods: This cross-sectional study included 412 participants categorized into four groups: pre-clinical dental students, clinical dental students, practicing dentists, and laypeople. Participants rated 20 photographs depicting variations in maxillary midline diastema, central incisor crown length, smile arc, gingival display, and incisal plane cant on a ten-point attractiveness scale. Personality factors were assessed using the NEO-FFI questionnaire, measuring Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness.

Results: Dental professionals assigned significantly lower aesthetic scores to smiles with a 2.0 mm central incisor crown reduction, a 4.0 mm gingival display increase, and an incisal plane cant compared to non-dental raters (P < .05). Higher Agreeableness and Conscientiousness scores were associated with a preference for smiles without midline diastema (r = .118, 0.112; P = .017, 0.023). Higher Extraversion and Openness scores were associated with a preference for no gingival display (r = .147, 0.123; P = .003, 0.012).

Conclusions: Perceptions of smile aesthetics varied significantly between dental and non-dental raters. Severity of smile discrepancy has a predictive role in aesthetic preferences, influencing the perceived attractiveness of specific smile characteristics. Personality factors had some associations with the perceived attractiveness of specific smile characteristics. Understanding how severity of smile discrepancy, personality traits and dental training influence esthetic preferences can help clinicians better tailor smile design and treatment communication to individual patient expectations.

Background: Miniscrew-assisted palatal expansion techniques such as MARPE (Miniscrew-Assisted Rapid Palatal Expansion) and MASPE (Miniscrew-Assisted Slow Palatal Expansion) represents non-surgical alternatives for the correction of transverse maxillary deficiencies in adults. However, concerns have arisen regarding their potential to cause craniofacial complications due to the high forces applied for midpalatal suture opening in skeletally mature patients.

Methodology: This article aims to present and describe isolated clinical cases of cranialfacial complications observed in adult patients following MARPE and MASPE procedures, and to discuss the potential biomechanical mechanisms behind these events. Eleven clinical cases involving adult patients who underwent skeletal midface expansion with miniscrew-assisted devices are presented. All cases exhibited craniofacial unwanted dislocations identified through CBCT imaging, including zygomatic fractures, parasutural bone fractures, and asymmetrical disjunction of craniofacial sutures. These events were retrospectively documented through clinical follow-up and radiographic analysis.

Results: Among the eleven cases presented, complications included seven asymmetric fractures of the frontonasal process, two orbital fractures, one zygomatic bone fracture, and one parasagittal fracture of the palatine bone. These complications were primarily observed in patients who underwent MARPE with rapid activation protocols. One minor complication occurred in a MASPE case, where the patient followed the prescribed slow activation schedule.

Conclusion: Non surgical mid facial expansion is a potential source of unwanted and unpredicted dislocations in the craneofacial complex. According to this report the observed complications do not seem to be age related and are difficult to predict from the CBCT. A close clinical follow up including force monitoring and force limitation should be mandatory when performing MARPE. MASPE and minimally invasive SARPE could be alternatives to minimise the incidence of creaniofacial complications.

Background: The application of deep learning techniques in cephalometric analysis has become increasingly prominent. Although automatic landmarking models for cephalometric analysis have been developed, their accuracy still requires validation and relies heavily on clinicians to resolve discrepancies between results. To address these limitations, automatic diagnostic models have gained attention. However, there is no direct evidence establishing the superiority of one model over the other, especially the generalization and transferability.

Methods: Based on the same northern Chinese population external test dataset data and the data of the IEEE (Institute of Electrical and Electronics Engineers) 2015 ISBI (International Symposium on Biomedical Imaging) Grand Challenge dataset, we compared the performance, generalization ability, and transfer ability of the proposed two models, respectively.

Results: Our findings suggest that the automatic landmarking model outperforms the automatic diagnostic model in both external test dataset, with an accuracy of 90.80% on the IEEE dataset.

Conclusions: In this study, the comparison was indirect, with each model having its strengths: the automatic landmarking model offers precise measurements, while the automatic diagnostic model provides quicker results. The choice between them depends on clinical needs, and future work should explore hybrid models to combine the advantages of both.

This narrative review critically summarizes that microplastics and nanoplastics have been found in many different environments, including water and food, raising concerns on their possible harm to human health. Previous research indicates that microplastics may cause inflammation and tissue damage; however, the full extent of their health risks remains uncertain. Given the long-term use of plastic-based orthodontic appliances such as aligners, retainers, and widespread usage of adhesives, the potential release of microplastics and nanoplastics during routine wear and mechanical stress warrants thorough investigation to ensure patient safety and long-term biocompatibility. The literature search conducted for this review was structured but non-systematic, with no formal risk-of-bias evaluation. This review aimed to critically evaluate the impact of microplastics and nanoplastics on human health, with a focus on their relevance to orthodontics. The review also aimed to identify possible gaps in current research, particularly regarding the quantification of microplastic leakage from orthodontic appliances and their possible long-term effects. Current evidence highlights a clear need for more targeted research to inform and improve safety standards regarding microplastics and plastic usage in orthodontic and dental practice.

Background: Orthodontic tooth movement (OTM) is a complex biological process triggered by orthodontic forces (OF). This study aims to study the influence of sex and age on the gene expression of the dental pulp (DP) and periodontal ligament (PDL) of human premolars subjected to 7 and 28 days of OF in vivo.

Methodology: Linear mixed and negative-binomial models were used on previously published RNA sequencing (RNA-seq) datasets of DP and PDL tissue subjected to OF for 7 days and 28 days to verify if the effect of OF depends on sex and age. Differentially expressed genes (DEGs) were identified using false discovery rate and functional analysis was performed.

Results: The datasets consisted of 69 DP and 63 PDL samples from 46 and 41 patients respectively, with similar sex and age distribution. RNA-seq showed that sex did not influence the DP's gene expression profile, since only one DEG related to immune response was detected after 28-days of OF. In contrast, sex significantly affected PDL: 505 DEGs were found after 7 days of OF, related to bone homeostasis, osteoclastic activity and immune response. Age impacted both tissues; in DP, 18 DEGs related to Ca²⁺ regulation and DNA damage repair were found at 7 days, and 10 DEGs associated with repair and adaptive capacities emerged at 28 days. In PDL, 181 genes related to bone regeneration were identified at 28 days, with no DEGs noted at 7 days.

Conclusion: Our study demonstrates that under OF, DP's reaction is not sex-based, whereas PDL's is, particularly in the early phase of OTM, with women showing a more pronounced osteoclastic response. Age-related effects in DP tissue primarily influence Ca²⁺ homeostasis and DNA damage repair in early phases, and tissue repair and adaptive responses later. In contrast, age impacts PDL tissue mainly in the later stages of OTM, affecting its regenerative capacity.