Digital treatment planning software in clear aligner (CA) therapy incorporates virtual simulations to generate planned tooth movements. While baseline tooth positions constitute one of the geometric inputs to digital setups, limited information is available regarding the association between pre-treatment positional asymmetry and the magnitude of planned movements, and how these associations vary by tooth and movement type. A retrospective analysis was conducted on 65 patients (390 anterior teeth) treated with Invisalign®. Baseline malpositions of anterior teeth were measured using 3D digital models in ClinCheck®, while planned movements-including rotation, angulation, extrusion, and intrusion-were extracted from the corresponding digital treatment plans. Baseline asymmetry between contralateral teeth was calculated to quantify movement complexity. General Linear Model (GLM) regression analyses were employed to assess the relationship between initial asymmetry and the magnitude of planned movements. Descriptive statistics and normality assessments were also performed. In the 11-21 tooth pair, baseline asymmetry was significantly associated with planned extrusion (p = .002) and rotation (p < .001), but not intrusion (p = .190) or angulation (p = .270). For the 12-22 pair, significant associations were observed for intrusion (p = .008), angulation (p < .001), and rotation (p < .001), but not extrusion (p = .493). In the 13-23 pair, only extrusion was significantly associated with baseline differences (p < .001); no significant effects were observed for the other movement types. Baseline positional asymmetry was associated with variation in planned extrusion, intrusion, and rotation movements within digital CA setups. These findings should be interpreted as descriptive associations rather than evidence of software-imposed constraints or internal planning strategies, and underscore the relevance of baseline geometry when interpreting digitally planned tooth movements.

Successful canine derotation in Clear Aligner Therapy (CAT) relies on strategic attachment design, influencing force direction and root control. This study employs Finite Element Analysis (FEA) to compare the biomechanical efficacy of three attachment designs, aiming to optimize treatment strategies for canine derotation. A three-dimensional finite element model of the maxillary arch was developed to simulate the rotational movement of maxillary canine in CAT. Three attachment groups used for evaluation were- VL: Vertical-angulated labial attachments only, VLP: Vertical-angulated labial and palatal attachments, VLPPP: Vertical-angulated labial attachments with palatal pressure points. Incremental rotational force of 10, 20, 30, 40 degrees was applied across all three groups. Tooth displacement, attachment deformation, periodontal ligament (PDL) stress and alveolar bone stress were analyzed and compared using ANSYS simulation software. VLPPP showed the highest tooth displacement pattern of 0.017mm with incremental rotational force application but also exhibited highest stress concentration at PDL and alveolar bone level of 516.10 Mpa. VL showed the least tooth movement of 0.012mm and lowest stress levels of 374.33 Mpa. VLPPP generated the highest force output, but also induced the greatest biological stress. In contrast, VLP with dual surface attachments effectively facilitated tooth movement while minimizing biological stress. Multi-surface force application enhances biomechanical control in clear aligner canine derotation.

BackgroundTo 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).MethodologyAn 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.ResultsCompressive 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.ConclusionsCompressive 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.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40510-026-00607-4.

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.

BackgroundOrthodontic 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.MethodologyLinear 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.ResultsThe 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.ConclusionOur 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.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40510-025-00596-w.

BackgroundMaxillary 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).MethodsThis 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.ResultsThe 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.ConclusionsCustom 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.

BackgroundThe aims of this study were to gather expert agreement about essential aspects of clear aligner therapy (CAT) and to determine what research areas need further investigation.Materials and methodsA steering committee performed literature selection and compiled a list of 25 statements. This study used a modified Delphi method involving a panel of 23 international orthodontic experts. Six essential areas of CAT were investigated: treatment efficacy, quality of life, side effects, management of growing patients, treatment with extraction, and treatment of periodontal patients. A panel of experts assessed 25 statements using a 5-point Likert scale throughout 3 rounds of the study. A steering committee adjusted statements that failed to achieve consensus through either revision, splitting, merging, or complete removal.ResultsAfter the third round, 22 statements achieved consensus while 3 statements were rejected. The panel agreed that aligners could be used effectively in some types of malocclusions, such as those with mild or moderate crowding or open bite cases. The experts reached a consensus on the biomechanical limits of clear aligners. However, they agreed on the benefits in terms of improved quality of life during treatment and easier maintenance of oral hygiene maneuvers. Regarding specific patient categories, the panelists supported the use of aligners in periodontal patients with tooth migration requiring tipping movements. They also agreed on the advantages of using a rapid palatal expander over aligners in growing patients.ConclusionsThe panel members reached agreement on most topics. However, they acknowledged limitations in the current literature regarding root resorption and orthodontic relapse with CAT compared to fixed appliances. The absence of agreement on treatment duration, effects on skeletal growth, and the management of periodontally compromised patients highlights significant evidence gaps that warrant further research.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40510-025-00575-1.

BackgroundThis cross-sectional observational study seeks to determine the clinical differences in eruption failure of permanent first molars presenting in cases of ankylosis, failure due to mechanical obstruction (MFE), and failure due to genetic causes (PFE). A total of 34 patients between 7 and 12 years old (mean ± SD: 9.3 ± 1.28 years), with anomalies in the eruption of the first permanent molars, were selected based on clinical observation, the evaluation of orthopanoramic radiographs, and intra- and extra-oral photographs. Genetic testing was also conducted to identify variants of the PTH1R gene in 27 patients with clinical signs of PFE. The familial nature of the condition was investigated through anamnesis of the first-degree relatives.ResultsOut of the 34 patients, 3 were diagnosed with PFE, confirmed by the presence of PTH1R variants. Twelve patients showed clinical signs suggestive of MFE diagnosis. The remaining 19 cases, in which no variants of the PTH1R gene were found, were considered cases of ankylosis. Roots in ankylosed teeth were located in the basal bone and often dilacerated. The reduction of vertical growth of the alveolar bone was present in both PFE and ankylosis cases, but teeth were nearer to the basal bone in ankylosis cases. Infraocclusion of deciduous teeth was present in PFE and MFE cases. Asymmetry due to bilaterally unbalanced eruption of the teeth was present in six cases with ankylosis. Bilateral affection was noticed in one PFE case and 6 MFE cases. A descriptive statistical analysis using Fisher’s exact test was employed to evaluate the significant association between variables.ConclusionsThe study highlighted some characteristic signs that help in early diagnosis of cases of PFE, MFE, and ankylosis. However, genetic testing remains necessary to understand the nature of the most dubious cases.

BackgroundSkeletal Class II malocclusion, often associated with mandibular deficiency, is commonly treated with functional appliances. Precision Wings are a functional appliance that provides an alternative approach by combining mandibular advancement with dental alignment.ObjectiveThis systematic review aimed to evaluate the effectiveness of Precision Wings in treating skeletal Class II malocclusion in growing patients.Eligibility criteriaStudies assessing the correction of skeletal Class II malocclusion in growing patients treated with Precision Wings were selected according to the PICOS strategy. The PRISMA guidelines were followed.Information sourcesUnrestricted electronic searches were conducted across seven databases up to February 2025.Risk of bias and synthesis of resultsThe ROBINS-I tool was used to assess the risk of bias (RoB) in non-randomized studies. A random-effects meta-analysis was performed, and the certainty of the evidence was evaluated using the GRADE approach.ResultsSeven studies were included, and data were extracted. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated using random-effects meta-analysis. The findings suggest that Precision Wings may be effective in treating skeletal Class II malocclusion in growing patients through both dental and skeletal changes. Regarding skeletal effects, sagittal changes were limited to the mandible and were of small magnitude, with a reduction in ANB° (MD = -0.81; 95% CI: -1.04 to -0.58; p < 0.001) occurring exclusively due to an increase in SNB° (MD = 0.55; 95% CI: 0.11 to 0.98; p = 0.01), while no significant changes were observed in SNA° (MD = -0.02; 95% CI: -0.42 to 0.38; p = 0.91). The included studies did not report significant vertical effects. Meta-analyses comparing Precision Wings with other functional appliances were not feasible due to the small number of studies evaluating each comparison and the substantial clinical and methodological heterogeneity across the included studies.ConclusionAlthough the available scientific evidence on this topic is limited, treatment with Precision Wings appears to offer minimal clinical improvement in mandibular growth for the correction of skeletal Class II malocclusion. To obtain more conclusive findings, future research should prioritize well-structured randomized clinical trials with standardized treatment protocols, extended follow-ups, and consistent cephalometric assessment methods.

IntroductionAchieving a harmonious soft tissue profile and enhancing facial appearance are key goals of early treatment for skeletal class III malocclusion.AimTo summarize the current evidence regarding the effects of Class III orthodontic treatment on facial soft tissues, and to compare various Class III orthodontic appliances.MethodsA 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.ResultsThirty 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.ConclusionsThere 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.RegistrationPROSPERO (CRD42024517924).