European journal of orthodontics最新文献

Objective: To determine whether miniscrew-root contact can be diagnosed by assessing tooth mobility before and after miniscrew implantation.

Materials and methods: Cadaveric pig mandibles were used, with 80 miniscrews placed mesial to the first premolars and distal to the fourth premolars. Maximum insertion torque (MIT) was measured for the first premolar miniscrews. Tooth mobility was assessed before and after implantation, and the Periotest Value difference (PTV-Diff) was calculated. Miniscrew-root distance (MS-R Dist) was measured using computed tomography. Spearman's rank correlations were analysed between MS-R Dist and PTV-Diff, and between MS-R Dist and MIT. Diagnostic efficacy was assessed using receiver-operating characteristic (ROC) curve analysis.

Results: PTV-Diff exhibited a positive correlation with MS-R Dist (rs > 0.7, P < 0.001), confirming reduced tooth mobility when miniscrews contacted tooth roots. PTV-Diff demonstrated high diagnostic accuracy, with an area under the ROC curve > 0.9, outperforming MIT. Three observed root fractures influenced the correlation between MS-R Dist and PTV-Diff.

Limitations: The primary limitation is the use of cadaveric mandibles, allowing ideal perpendicular percussion with the Periotest system, which may be challenging to replicate in humans due to anatomical constraints.

Conclusion: Our results suggested that PTV-Diff effectively diagnoses miniscrew-root contact, outperforming MIT. Differences between first and fourth premolars emphasize the need for tooth-specific cut-off values in clinical applications. Root fractures significantly affected diagnostic accuracy, underscoring the importance of multiple PTV measurements during miniscrew placement. Measuring tooth mobility before and after miniscrew implantation may hold promise as a diagnostic approach for detecting miniscrew-root contact.

Background: Therapeutic mouthwashes are commonly used in dentistry to support mechanical plaque removal. Their interaction with orthodontic materials is increasingly studied due to potential effects on biocompatibility and biomechanics.

Objective: To investigate in a systematic manner and evaluate the quality of the available evidence from randomized clinical trials regarding the effects of various mouthwashes on the morphology, structure, and mechanical properties of polymeric and metallic orthodontic materials.

Search methods: Comprehensive electronic and manual searches were conducted in seven databases from inception until August 2024.

Selection criteria: We analysed randomized controlled clinical studies that examined the impact of mouthwashes on the morphology, structure, and mechanical properties of both polymeric and metallic orthodontic materials.

Data collection and analysis: Data eligibility, data extraction, and risk of bias (RoB-2 tool) were performed independently.

Results: Ten studies were included, with most of them presenting some concerns in terms of bias. Chlorhexidine mouthrinse use did not affect the shear bond strength of polycarbonate brackets, the soldering alloys, as well as the stainless-steel bracket surfaces, but increased the roughness and friction of stainless-steel wires. The corrosion and mechanical properties of NiTi wires were not significantly affected by chlorhexidine. Rinsing with fluoride solutions increased surface roughness of NiTi wires, with more pronounced effects seen in acidulated fluoride solutions. While yield strength increased, no significant impacts on unloading force or modulus of elasticity was observed. Mouthwashes containing Salvadora persica did not significantly alter the surface topography of stainless-steel brackets and the roughness of stainless-steel archwires.

Conclusions: The evidence from randomized clinical trials suggests that chlorhexidine- and fluoride-containing mouthwashes may impact the structure and certain mechanical properties of stainless-steel and NiTi archwires. While study limitations exist, clinicians should be mindful of possible effects on orthodontic treatment.

Registration: Open Science Framework: osf.io/hz6wk.

Introduction: This study aims to evaluate the predictability of derotation in incisors, canines, and premolars, as well as to determine overtreatment ratios associated with derotation using clear aligners.

Methods: This study included 461 rotated teeth from 44 patients undergoing Invisalign® (Align Technology, Santa Clara, CA) clear aligner treatment. The sample was divided into maxillary and mandibular incisors, canines, and premolars. The occlusal and mid-sagittal planes were constructed, and derotation angles and efficiencies were measured using intraoral scans imported into Geomagic Control X (3D Systems, Rock Hill, SC, USA, 2022). Age, sex, skeletal patterns, derotation direction, anterior spacing, premolar extraction, attachment types, and direction of intermaxillary elastics traction were recorded and analyzed for their correlation with derotation discrepancies. Calibrated predictability values were reevaluated, and the corresponding overtreatment design ratios were determined.

Results: There was no significant difference in derotation effectiveness across tooth types (P > 0.05). The discrepancy between the predicted and achieved derotation values was significantly correlated with the designed derotation values for maxillary teeth and mandibular incisors (P < 0.001). Multivariate analysis revealed that age, sex, skeletal patterns, derotation direction, anterior spacing, premolar extraction, attachment types, and direction of intermaxillary elastics traction differentially influenced derotation movements. The suggested overtreatment ratios for maxillary incisors, mandibular incisors, maxillary canines, and maxillary premolars are 27%, 30%, 35%, and 38%, respectively.

Conclusions: Derotation predictability is primarily influenced by factors such as the magnitude of derotation, available space, derotation direction, intermaxillary elastics traction direction, and the mesiodistal/buccolingual ratio, but not by the type of attachment used.

Purpose: This study aimed to compare the initial forces and moments exerted by 3D-printed clear aligners on a maxillary left lateral incisor during distal rotation using pressure points and/or relief channels.

Materials and methods: An in vitro setup using multi-axis force/moment transducers measured forces and moments on tooth 22, rotated 3° distally. Six experimental groups were tested, using TC-85 clear resin aligners with varying pressure points (PP) and relief channel configurations: Group 1 (CON): Control with no PPs or channels; Group 2 (FP): Facial PP on the distofacial aspect; Group 3 (LP): Lingual PP on the mesiolingual aspect; Group 4 (DBL): Combined facial and lingual PPs; Group 5 (FWR): FP with a distolingual relief channel; and Group 6 (LWR): LP with a mesiofacial relief channel.

Results: Adding PPs generally increased the desired distal rotational moment, with LP showing the highest and CON the lowest rotational moment. However, relief channels yielded mixed outcomes. CON, FP, and FWR showed significant lingual forces, while LP, DBL, and LWR produced facial forces. All groups exhibited distal forces, except for CON and FP which generated mesial forces (p < 0.001). Also, all groups demonstrated intrusive forces except for the DBL group, which showed significant extrusive forces (p < 0.001). CON, FP and LP produced facial torque, whereas DBL, FWR, and LWR resulted in lingual torque. Groups without relief channels (e.g. FP, LP) demonstrated no significant differences in faciolingual or incisogingival forces compared to their relief-channel counterparts (FWR, LWR), though FP showed a significantly lower distal rotational moment than FWR and LP produced significantly higher rotational moments than LWR. DBL showed no significant difference in faciolingual and mesiodistal forces compared to LP but showed significant opposite forces when compared to FP. Moreover, DBL showed a significantly higher distal rotational moment than FP but lower than LP (p < 0.001).

Conclusions: Pressure points in 3D-printed aligners create rotational moments on maxillary lateral incisors without the need for attachments. These findings highlight the clinical potential of direct-printed aligners to deliver customized biomechanics for improved predictability.

Background/objectives: In individuals with cleft lip and palate, nasolabial asymmetry and dysmorphology are associated with lower aesthetic ratings, though this relationship remains unclear. This study examines how deviations in nasolabial shape from the average affect aesthetic ratings.

Materials/methods: 3D stereophotogrammetric images were taken from 53 children with unilateral cleft lip and palate (UCLP) (34 boys, 19 girls; mean age: 10.5 ± 0.6 years) and 53 age and sex-matched children without cleft. UCLP repair was performed by three experienced surgeons in a single stage at 8.2 ± 2.3 months. An average 3D nasolabial shape model of noncleft individuals was created via geometric morphometrics with 10 fixed points and 100 semilandmarks. The Procrustes distances of the noncleft average shape from each cleft shape quantified nasolabial dysmorphology, while 15 laypersons rated nasolabial aesthetics on a 100-mm visual analogue scale (VAS; lower scores = poorer aesthetics). Internal rater-consistency was assessed via the intraclass correlation coefficient (ICC). Correlation analysis examined the relationship between aesthetics and nasolabial dysmorphology in the cleft group.

Results: The mean ICC of 0.85 (95% CI: 0.78-0.91) indicated high consistency among the raters. The average aesthetic rating for the cleft group was 42.2 ± 16.5. The mean Procrustes distance was 0.0993 ± 0.0205. Greater deviation from the average noncleft shape was associated with lower aesthetic ratings (Pearson's r = -0.282, p = 0.041).

Limitations: This single-centre, retrospective study may have selection bias and limited generalizability, with a predominantly prepubertal sample.

Conclusions/implications: Nasolabial aesthetics is influenced by the degree of deviation from the average noncleft shape, although this relationship explains only a small portion of the variance (R2 = 0.08). Other factors likely contribute to nasolabial aesthetic ratings.

Background/objectives: Recent advances in AI have enabled its application in dentistry. This study assessed the diagnostic accuracy of an AI-based model (Diagnocat™) in detecting congenitally missing and supernumerary teeth on panoramic radiographs.

Materials/methods: Three groups of 50 orthopantomograms each-control, congenitally missing, and supernumerary teeth-were evaluated by two human observers and Diagnocat™. Diagnostic performance was compared using the Wilcoxon Signed Rank and McNemar's tests. Agreement was measured using Cohen's Kappa, and diagnostic metrics (sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)) were computed using IBM SPSS 29.0.

Results: For congenitally missing teeth, Cohen's Kappa indicated strong agreement (0.91); however, significant differences were found in the diagnostic performance (p < 0.01). The model exhibited 84.7% sensitivity, 100.0% specificity, 100.0% PPV, and 99.4% NPV. For supernumerary teeth, the agreement was moderate (Kappa = 0.60), with significant differences in the diagnostic performance (p < 0.001). Sensitivity was 43.9%, while specificity, PPV, and NPV were 100.0%, 100.0%, and 98.9%, respectively.

Limitations: Using convenience sampling and a retrospective design may affect generalizability and applicability.

Conclusions/implications: Although the AI-based model shows promise, it is not yet able to replace human assessment as the standard for detecting missing and supernumerary teeth in panoramic radiographs.

Objective: The aim of this study was to investigate the electrochemical characteristics and ionic release of three-dimensional (3D) printed orthodontic metallic bands made of stainless-steel (SS) and Cobalt-Chromium (Co-Cr) alloys.

Materials and methods: Thirty-six orthodontic metallic bands were prepared by 3D printing, employing SS (n = 18) and Co-Cr (n = 18) alloys. The ionic release from each alloy was determined according to ISO 27020:2019 requirements employing flame atomic absorption spectrometry (FAAS). The electrochemical properties were characterized by Open Circuit Potential (OCP), Anodic Scan (AS) and Electrochemical Impedance Spectroscopy (EIS). In all cases a 0.1M NaCl, 0.1 M lactic acid solution was used. The EIS data were fitted to a Randles circuit and the sum of ionic release of probed elements after immersion along with OCP, zero corrosion potential (Ecorr), corrosion current density (Icorr), and pitting corrosion potential (Epit) were compared with t-tests/Mann-Whitney tests (α = 0.05).

Results: SS bands showed an approximately 44-fold higher total ionic release compared to Co-Cr ones. Electrochemical testing revealed no statistically significant differences for Ecorr but Co-Cr illustrated more beneficial OCP, Icorr and Epit values than SS. Both alloys illustrated semicircles in Nyquist plots, implying that the electrochemical process was under charge transfer control, while the equivalent circuit simulation showed a higher charge transfer resistance for Co-Cr alloy (SS:14191.1 vs Co-Cr:33158.7 Ωcm2), implying lower corrosion current and thus decreased corrosion rate.

Conclusion: Immersion and electrochemical testing indicated that Co-Cr alloys showed increased corrosion resistance over SS ones, which might affect efficacy under clinical use.

Background: In many European countries, orthodontic treatment is offered in publicly funded healthcare to those with severe malocclusion. In the Finnish public health care, the modified Grainger's treatment priority index (TPI) is used to determine malocclusion severity and treatment eligibility. The uniform use of occlusal indexes is crucial for equitable treatment allocation.

Objective: This study aimed to investigate equity in access to orthodontic care in one wellbeing services county in Finland.

Materials and methods: We conducted five calibration events, where five orthodontists were calibrated against one gold standard orthodontist with the longest clinical experience. All the orthodontists independently clinically examined random groups of patients using the Finnish modified TPI scoring. The malocclusion severity scores, diagnosis codes, and the determined treatment eligibility were subsequently compared. Agreement between the orthodontists was analyzed with Cohen's Kappa and Bland-Altman statistics.

Results: In total, 166 patients, aged 6-63 years, were examined across the calibrations, each representing a comparison between one of the five orthodontists and the gold standard. The agreement between the orthodontists was found to be substantial. The same judgement on treatment eligibility was made in 145 out of 166 cases (87%), whereas a different decision on treatment eligibility was made in 21 cases (13%).

Conclusions: Despite the high level of interobserver agreement, differences in eligibility judgement were observed, which may have important consequences for the patient with respect to treatment provision. Therefore, systematic calibration and regular training in the use of national occlusal indexes should be implemented for all orthodontists.

Background/objectives: Gingival recession results from the displacement of the gingival margin apically to the cementoenamel junction. There is unclear evidence regarding the impact of orthodontic treatment on the development of gingival recessions. The aim of this study was to investigate the changes in clinical crown length and the development of gingival recession on the labial aspect of the maxillary and mandibular incisors associated with orthodontic treatment and relate these changes to the observed variations in their sagittal inclination.

Materials/methods: Eighty-two consecutive subjects treated with fixed orthodontic appliances in both dental arches, possessing high-quality pre- and post-treatment dental casts and lateral cephalometric radiographs, were selected from the archives of a private orthodontic clinic. Incisor clinical crown lengths before and after orthodontic treatment, as well as the presence or absence of recession, were measured using digitized study models. Changes in sagittal inclination were assessed from lateral cephalometric radiographs and categorized as proclination, retroclination, or no change (± 1°). Spearman's correlation coefficient, one-way analysis of variance, and chi-square tests were utilized for analysis.

Results: The mean change in clinical crown lengths for the maxillary incisors ranged from -0.24 to 0.01 mm, while for the mandibular incisors, it varied from 0.06 to 0.10 mm. The inclination changes were -1.78° and 1.03°, respectively, but no correlations were found between these inclination changes and the clinical crown length alterations. Overall, no statistically significant differences were observed in clinical crown length changes concerning the presence of gingival recession among the proclination, retroclination, and no change groups.

Limitations: The sample of this study was retrospective and assessments were carried out immediately post-treatment.

Conclusions/implications: The alteration of incisor inclination during treatment did not appear to impact the changes in labial clinical crown length and the development of gingival recession in this specific sample.

Background: An increasing number of adults with periodontitis are pursuing orthodontic treatment to enhance their occlusion and aesthetics. To manage these patients effectively, it is essential to develop a tailored orthodontic treatment plan that addresses key factors such as anchorage, biomechanics, and interdisciplinary collaboration between orthodontists and periodontists. This comprehensive approach can significantly improve treatment outcomes.

Objectives: This study aims to identify the most effective orthodontic protocols for treating patients with periodontitis or a reduced periodontium, paving a foundation for better clinical practices and improved patient satisfaction.

Search methods: The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline. Selection Criteria: It focused on patients aged 20-50 years, with no systemic disorders, and studies published since 2000.

Data collection and analysis: Data was collected and the quality was assessed using the Critical Appraisal Skills Program (CASP) checklist. A meta-analysis was performed using the R program, with I2 used to quantify heterogeneity. Sensitivity analysis was performed on each subset of studies.

Results: The sensitivity analysis reveals that orthodontic therapy significantly resulted in improved clinical attachment level (CAL), with a pooled mean gain of 3.84-4.34 mm. Also, a significant reduction in probing depth (PD) with a pooled mean reduction of 4.32 mm was revealed after orthodontic treatment for periodontitis patients .

Conclusion: This study suggested that individualized, interdisciplinary orthodontic and periodontic protocols are crucial for managing patients with periodontitis or reduced periodontium. Tailored approaches using conservative forces and regenerative strategies significantly improve clinical outcomes, making one-size-fits-all methods inadequate.

Registration: PROSPERO: ID: CRD42024573973.