Orthodontics & Craniofacial Research最新文献

Objectives

To investigate the prevalence and contributing factors of mandibular labial gingival recession in patients with fixed lingual orthodontic retainers.

Methods

This cross-sectional study involved 83 post-orthodontic patients with fixed lingual retainers. Labial gingival recession was assessed on the lower incisors and classified using Cairo's Recession Type system. Clinical parameters were collected, including bleeding on probing, biofilm, brushing habits and oral hygiene behaviours. Logistic regression was used to analyse factors associated with recession.

Results

Labial gingival recession was observed in 27 of 83 patients (32.53%). The mean recession was 0.66 mm. Significant associations were found between gingival recession, age (p = 0.008) and nail/pen/pencil biting habits (p = 0.021). Brushing technique and frequency also showed a significant association.

Conclusions

Labial gingival recession was present in one-third of patients with fixed lingual retainers. Age and mechanical habits, such as nail-biting, were significant predictors. Preventive strategies should target behaviour modification and enhanced oral hygiene education.

Objectives

This study aimed to establish a clustering-based classification model for skeletal expansion outcomes after miniscrew-assisted rapid maxillary expansion (MARPE) and evaluate its clinical implications.

Material and Methods

The study samples comprised 61 patients with transverse discrepancy who underwent maxillary skeletal expansion using MSE I. Cone-beam computed tomography images before (T0) and after (T1) expansion were analysed with nine measurements assessing transverse changes in the maxilla, molars and appliance. Gaussian mixture model clustering, random forest models and decision trees identified expansion patterns and key classifiers, establishing a classification system. Two- and one-way analyses of variance compared intergroup characteristics.

Results

The clustering-based classification model identified four distinct clusters of skeletal expansion patterns, establishing two key classifiers: expansion efficiency (good/poor) and parallelism (parallel/V-shaped). Poor responders had an older age and showed significantly lower efficiency, more V-shaped tendencies, greater activation loss and longer intervals until interincisal diastema than good responders (p < 0.001). V-shaped responders exhibited less efficiency, reduced posterior expansion and increased miniscrew slippering (p < 0.001). Twenty days until interincisal diastema can be used to monitor expansion efficiency. Age is a useful predictor of efficiency, except during the ambiguous period of 16.81–20.14 years (17.91–19.88 for males, 16.95–18.94 for females) and for outliers.

Conclusion

This study introduces a concrete classification system for MARPE outcomes, emphasising the role of expansion efficiency and parallelism in optimising clinical results. These four identified phenotypes provide a data-driven validation of the existing concepts of expansion patterns and their implications for treatment.

Objective

This study aims to investigate the correlation between alveolar bone loss and IMPA (Incisor Mandibular Plane Angle) in individuals with skeletal Class III malocclusion during pre-surgical orthodontic decompensation (POD).

Materials and Methods

This retrospective cohort study evaluated 90 Class III patients, grouped by initial IMPA into Low-IMPA group (IMPA ≤ 78.5°), Moderate-IMPA group (78.5 < IMPA ≤ 85.7) and High-IMPA group (IMPA > 85.7), and by IMPA change into Small-change group (change ≤ 3.7°), Moderate-change group (3.7 < change ≤ 8.17°) and Large-change group (change > 8.17°). Cone-beam computed tomography (CBCT) measured alveolar bone area (ABA), vertical bone level (VBL), mid-root horizontal thickness (mHBT) and apical horizontal thickness (aHBT). Mandibular regional superimpositions were used to measure horizontal and vertical movements of the incisal edge and root.

Results

Before POD, mHBT, aHBT and ABA were highest in the High-IMPA group and lowest in the Low-IMPA group, while VBL was highest in the Low-IMPA group and lowest in the High-IMPA group. After POD, significant changes were observed only on the lingual side, with the same pattern. Labial aHBT and ABA changes followed Large-change group > Moderate-change group > Small-change group, whereas lingual aHBT and ABA changes followed the opposite pattern.

Conclusion

Higher initial IMPA correlated with better alveolar bone condition before POD and better lingual bone condition after POD. Greater IMPA change during POD was linked to increased labial bone thickness and area, but reduced lingual bone thickness and area. The horizontal backward movement of the root apex was the primary factor driving these changes.

Transverse maxillary deficiency, a common skeletal discrepancy among children and adolescents globally, can be treated using either bone-anchored (BA) and tooth-borne (TB) maxillary expanders. This systematic review and meta-analysis evaluated the three-dimensional (3D) difference in the skeletal and dentoalveolar effects of both expander types in growing patients. A systematic literature search was performed across four electronic databases to identify randomised clinical trials that evaluated the skeletal and dentoalveolar effects of BA and TB maxillary expanders using 3D radiographic images with comparisons made immediately after expansion, within 6 months, and beyond 6 months. Following risk of bias assessment, dimensional changes in sutural expansion (SE), nasal width (NW), maxillary width (MW), as well as tooth inclination (TI) and buccal bone thickness (BBT) of posterior tooth regions were extracted and pooled for further meta-analyses. The analyses were performed based on evaluation periods to determine immediate, short-term, and long-term effects. Among 1432 records that have been retrieved, ten studies followed our predetermined eligibility criteria, thus included in this systematic review for qualitative synthesis. Nine of them were able to undergo quantitative synthesis. Regarding the immediate effect, BA expanders presented significantly higher SE, NW, and MW changes than TB expanders, while showing no significant difference in TI and BBT at the molar region. During the first 6 months after expansion (short-term), evidence has shown that the skeletal and dentoalveolar effects were more favourable to BA expanders in terms of greater nasal width changes and less TI for premolars and molars. However, there were particularly insufficient studies that investigated the long-term skeletal and dentoalveolar effect differences, though there might be greater nasal width changes after 6 months. Current evidence suggests that hybrid/BA expanders produce significantly greater skeletal effect than tooth-borne expanders in the immediate and short term. These effects include increased sutural opening and nasal width, alongside less premolar buccal tipping and greater buccal bone thickness at the premolar and molar region less than 6 months after expansion. Over time, the differences between groups appear to diminish time, indicating potential instability in the long-term outcomes. Due to the high heterogeneity among studies and low quality of evidence reported, these findings should be interpreted with caution. Further studies with more standardised ways would be needed, particularly for long-term changes.

Registration

PROSPERO (CRD42023399235).

Background

Orthodontic tooth movement (OTM) pain poses a significant clinical challenge, yet its underlying molecular and cellular mechanisms remain incompletely understood.

Methods

We established a mouse OTM model validated by micro-CT and histology, alongside pain assessments (Mouse Grimace Scale, bite force). Bulk RNA-seq was performed on trigeminal ganglion (TG) tissues, integrated with public single-cell RNA-seq data for a more comprehensive view, and key genes were confirmed via qPCR and immunofluorescence. A user-friendly web platform (OTMPTGTA) was developed to enable researchers to explore differentially expressed genes, gene correlations and gene-set analyses without specialised coding skills.

Results

OTM induced both significant tooth movement and heightened pain, peaking at Day 3. Transcriptomic analyses pinpointed an Atf3+ population of injured TG neurons that showed marked upregulation of xanthine dehydrogenase (Xdh) during peak pain; by Day 14, both gene expression levels and pain scores subsided. QPCR and immunofluorescence confirmed coexpression of Atf3 and Xdh at Day 3, implicating Xdh in nociceptive signalling. The OTMPTGTA platform facilitates further exploration of these and other potential pain-related pathways, offering novel insights for targeted intervention.

Conclusions

Xdh is highly expressed in Atf3+ injured neurons during OTM pain, likely intensifying nociceptive signals through oxidative and inflammatory pathways. These findings highlight Xdh as a promising therapeutic target for alleviating orthodontic pain while preserving effective tooth movement.

Objective

Orthodontic treatment is a common approach for correcting malocclusion but is often associated with discomfort. The aim of this study was to assess the longitudinal changes in oral behaviours, temporomandibular disorder (TMD)-related pain and anxiety among university students undergoing orthodontic treatment compared to untreated controls.

Materials and Methods

A prospective cohort study was conducted at the University of Trieste, Italy. Participants were grouped based on the presence or absence of active orthodontic treatment and asked to complete an electronic survey comprising the Oral behaviour checklist-21 (OBC-21), TMD pain screener and generalised anxiety disorder-7 (GAD-7) at baseline (T0), after 6 months (T1), 12 months (T2) and 18 months (T3). Repeated measures ANOVA analysed within-group changes over time, while mixed ANOVA assessed group–time interactions.

Results

A total of 114 participants completed all follow-ups, with 57 in each group and comparable sex distribution. In the orthodontic group, no significant changes were observed across the three measures (p > 0.05). The non-orthodontic group showed a slight increase in OBC-21 scores after 12 months (p = 0.034) and a decrease in GAD-7 scores after 18 months (p = 0.048). Mixed ANOVA confirmed the absence of significant changes in the pattern of scores between the orthodontic and non-orthodontic groups over time (p > 0.05).

Conclusion

Orthodontic treatment does not significantly influence oral behaviours, TMD-related pain or anxiety over time. Routine screening for these factors in orthodontic patients is not required as a standard practice for all orthodontic patients; instead, individualised assessment should be based on clinical indications.