European journal of orthodontics最新文献

Objective: The main objective was to analyse the clinical effectiveness of ramus mini-implant-assisted traction of mandibular second molars with eruption disturbances.

Materials and methods: A prospective study was carried out during a 3-year period. A total of 16 patients with 19 impacted mandibular second molars underwent surgical exposure followed by implant-assisted orthodontic traction. The pre- and post-treatment cone-beam computed tomography, and pre-, in-, and post-treatment panoramic radiographs were collected and measured for the changes in space, angles and alveolar bone at pre-, in-, and post-treatment stages.

Results: Mandibular second molars showed progressive uprighting (the angle between MM2 and the mandibular plane increased to 95.70 ± 11.96°, p < .0001) and improved root parallelism (the angles between MM2 and the mandibular second premolar decreased to 8.45 ± 7.06°, p < .0001) after the treatment. While molar crowns exhibited no significant deviation from the standard arch form, roots predominantly shifted lingually (2.29 ± 1.84 mm lingually at post-treatment, p < .05). Regarding alveolar bone changes, there was a significant increase of bone height at the distal side of the mandibular first molar (p < .05), coupled with a decrease of bone height at the mesial side of the second molar (p < .05). Root lengths of all patients indicated no statistical significance before and after treatment (p = .63).

Conclusion: Mini-implants placed at the mandibular ramus region are clinically effective in the orthodontic traction of impacted mandibular second molars. The orthodontic traction favours periodontal regeneration between first and second molars and bears no or minimal risk of root resorption of mandibular second molars.

Objective: This prospective controlled study aimed to assess whether changes in mandibular incisor inclination during orthodontic treatment with fixed appliances affect gingival thickness (GT) and the width of keratinized gingiva (WKG), and having as reference an untreated group of participants.

Materials and methods: Forty consecutively recruited adult orthodontic patients and 40 untreated volunteers, matched for age and gender and selected from the same background population serving as controls, were included. Mandibular incisor inclination was measured in lateral cephalograms before treatment commencement (T0) and 1 month before fixed appliances' removal (T1). Gingival thickness was measured using an Ultrasound Device (US) and width of keratinized gingiva (WKG) using a standard periodontal probe within the frames of a full periodontal examination at T0, T1, and 1 year after bracket removal (T2), that is, at about 30 months from T1.

Results: Nineteen females and 21 males in each group [mean age in years (range): intervention group 23.1 (16.8-43.3); control: 21.85 (18.2-43.9)] were analysed. Overall, change in incisor proclination [mean change in Incisor Mandibular Angle Plane-IMPA (ΔIMPA) was 6.35° (SD 5.08°)] was not associated with any significant change in soft tissue thickness and with alterations in WKG. The group receiving fixed appliances did not exhibit thickening or thinning of GT in comparison to the control group; the WKG was reduced in the intervention group in comparison to the untreated group, where it essentially remained unchanged (#41: coeff.: -0.29, P value: .1, 95% CIs: -0.65, 0.06; #31: coeff.: -0.51, P value: .01, 95% CIs: -0.88, -0.14).

Conclusions: Lower incisor proclination during orthodontic treatment does not appear to significantly alter GT and WKG, but orthodontic treatment, overall, leads to reduction of the WKG.

Background/objectives: Mandibular second molar (MdM2) is often lost, and its space is filled with a bridge or implant. MdM2 extraction followed by orthodontic treatment protracting mandibular third molar (MdM3) towards the MdM2 position may overcome the missing of MdM2. The objectives of our study were to describe the outcome of the procedure and examined clinical risk factors such as external apical root resorption (EARR) and alveolar bone loss (ABL), as the indicators of poor orthodontic treatment outcomes.

Materials/methods: This retrospective study included 70 cases in 56 patients who received orthodontic treatment at Tokyo Medical and Dental University Hospital between 2007 and 2018. Multi-bracket appliances were used in all patients for MdM3 protraction. Using linear mixed effects models, EARR and ABL were regressed on various factors, including panoramic and cephalometric variables.

Results: With the mean treatment duration of 1040.4 ± 441.8 days, MdM2 space closure was achieved in 92.8% (65 cases). The ANB angle (P = .023) and the use of temporary anchorage devices (TADs) (P = .021) were significantly associated with the greater EARR, while the mandibular plane angle (P = .033) was associated with the greater ABL. MdM3 protraction using the fixed appliances resulted in the closure of MdM2 space in > 90% of cases without evident root resorption.

Limitation: There is a possibility of residual confounding due to the nature of observational study.

Conclusion/implication: Orthodontic treatment of MdM3 protraction may be a feasible strategy to close the space of the missing MdM2.

Objectives: To compare cephalometric long-term outcomes in patients with unilateral cleft lip and palate (UCLP) and treated with three different surgical protocols for palatal repair. Furthermore, to investigate growth longitudinally and evaluate the possibility to predict the outcome at age 19 from cephalometric values at 5 years.

Materials/methods: Lateral cephalograms of 68 patients, operated according to the Veau-Wardill-Kilner technique (n = 13), the minimal incision technique (n = 39), or MIT with muscle reconstruction (MITmr) (n = 16) were assessed. At a mean age of 19.0 (SD 0.7) years, 17 skeletal and 6 soft tissue variables were analysed using analysis of variance (ANOVA) with pairwise comparison. Lateral cephalograms at a mean age of 5.1 (SD 0.4) years, from 32 of the 68 patients were used to predict values at 19 years, using a multiple linear regression.

Results: There were statistically significant differences between the three surgical techniques for eight of the skeletal variables and for two of the soft-tissue variables at 19 years. The angle between the sella/nasion plane and the nasion/A plane (SNA) was 74.5 (SD 3.8) after Veau-Wardill-Kilner (VWK), 77.6 (SD 5.3) after minimal incision technique (MIT), and 76.7 (SD 2.6) after MITmr. Adjusted for baseline values, at 5 years, only face height had a significant effect dependent on surgical technique.

Limitations: Due to the exclusion criteria or missing medical records, only 43% of 157 consecutive patients could be included in the study.

Conclusion: MIT and MITmr resulted in better cephalometric results regarding facial growth sagittally and vertically compared to VWK. Most of the cephalometric variables measured showed a strong positive relation between the value at 5 and the value at 19 years of age.

Background: Automatic landmarking software packages simplify the analysis of the 3D facial images. Their main deficiency is the limited accuracy of detecting landmarks for routine clinical applications. Cliniface is readily available open-access software for automatic facial landmarking, its validity has not been fully investigated.

Objectives: Evaluate the accuracy of Cliniface software in comparison with the developed patch-based Convoluted Neural Network (CNN) algorithm in identifying facial landmarks.

Materials /methods: The study was carried out on 30 3D photographic images; twenty anatomical facial landmarks were used for the analysis. The manual digitization of the landmarks was repeated twice by an expert operator, which considered the ground truth for the analysis. Each 3D facial image was imported into Cliniface software, and the landmarks were detected automatically. The same set of the facial landmarks were automatically detected using the developed patch-based CNN algorithm. The 3D image of the face was subdivided into multiple patches, the trained CNN algorithm detected the landmarks within each patch. Partial Procrustes Analysis was applied to assess the accuracy of automated landmarking. The method allowed the measurement of the Euclidean distances between the manually detected landmarks and the corresponding ones generated by each of the two automated methods. The significance level was set at 0.05 for the differences between the measured distances.

Results: The overall landmark localization error of Cliniface software was 3.66 ± 1.53 mm, Subalar exhibiting the largest discrepancy of more than 8 mm in comparison with the manual digitization. Stomion demonstrated the smallest error. The patch-based CNN algorithm was more accurate than Cliniface software in detecting the facial landmarks, it reached the same level of the manual precision in identifying the same points. The inaccuracy of Cliniface software in detecting the facial landmarks was significantly higher than the manual landmarking precision.

Limitations: The study was limited to one centre, one groups of 3D images, and one operator.

Conclusions: The patch-based CNN algorithm provided a satisfactory accuracy of automatic landmarks detection which is satisfactory for the clinical evaluation of the 3D facial images. Cliniface software is limited in its accuracy in detecting certain landmark which bounds its clinical application.

Introduction: B-cell lymphoma 6 (Bcl6) inhibits osteoclast differentiation in vitro; however, its role in orthodontic tooth movement (OTM) remains unclear. This study aimed to investigate the role of Bcl6 in OTM of rat molars.

Materials and methods: OTM was performed on the maxillary first molars of male rats using nickel-titanium coil springs (25 gf) for 14 days with or without local injection of FX1 (50 mg/kg), a Bcl6 inhibitor (n = 10 per group). Micro-computed tomography (CT) images were used to analyse OTM distance and bone morphometric parameters. Immunohistochemistry (IHC) determined Bcl6 expression and tartrate-resistant acid phosphatase staining (TRAP) staining assessed osteoclast differentiation. TRAP staining, and reverse transcription-quantitative polymerase chain reaction determined the effect of FX1 (1 μM) on in vitro rat osteoclast differentiation. The effect of FX1 on cell proliferation and Smad4 expression in periodontal ligament (PDL) cells was determined.

Results: Administration of FX1 significantly increased OTM distance and decreased the bone/tissue volume compared with vehicle treatment. IHC staining showed that the vehicle-OTM group had higher expression of Bcl6 than the FX1-OTM group. The number of osteoclasts on the compression side was significantly higher in the FX1-OTM group than that in the vehicle-OTM group. FX1 enhanced osteoclast differentiation and expression of Nfatc1, Dc-stamp, and Ctsk mRNA in osteoclasts in vitro. FX1 significantly promotes PDL cell proliferation in vivo and in vitro.

Limitations: We evaluated only 14 days of OTM.

Conclusions: Bcl6 may play an important role in OTM via modulation of osteoclast differentiation and PDL cell proliferation.

Background: The study aimed to compare the short- and long-term effectiveness of hybrid Hyrax (HH) -Facemask (FM) and HH-mentoplate (MP) treatment protocols for maxillary protraction using Alt-RAMEC.

Methods: A single-center 2-arm parallel randomized controlled trial. Participants: 28 skeletal class III patients (female: 14, male: 14; average age: 9.7 ± 1.3 years;) were included. Interventions: Two treatment groups where protraction therapy was combined with Alt-RAMEC. Group 1: Facemask group (Hybrid Hyrax + Facemask) and Group 2: Mentoplate group (Hybrid Hyrax + Mentoplate). Objective: To compare skeletal and dental changes between groups using low dose computed tomography (CT) scan from which virtual lateral cephalograms were generated. Outcome: Outcomes include changes in Wits appraisal (primary outcome), and cephalometric analysis of skeletal and dental changes (secondary outcomes) at 1 year and 5 years after treatment initiation. Randomization: 28 patients were allocated to either treatment-protocols using sequentially numbered opaque, sealed envelopes. The randomization sequence was generated with a 1:1 allocation ratio. Blinding: Due to the nature of the trial, the operator and children could not be blinded to the treatment allocation. However, blinding was used when assessing the outcomes.

Results: Follow-up: one patient was lost at the one-year follow-up and an additional three patients were lost at the 5-year follow-up. Outcomes: Both treatment protocols effectively improved intermaxillary relationship. Wits measurements showed improvements of 4.42 mm (FM) and 2.86 mm (MP) at T1, decreasing slightly to 3.33 mm (FM) and 1.50 mm (MP) at T2. While vertical control and incisor inclination were comparable between groups long-term, short-term differences were noted in upper and lower incisor inclination. Results remained equally stable after five years (T2). Harms: minor harms were encountered with the anchor hooks (fracture or mucosal irritation), however none led to treatment cessation.

Conclusions: Early class III treatment with HH + MP provided similar outcomes and stability to that of HH + FM suggesting that the choice between FM and MP should be based on individual patient factors rather than presumed mechanical advantages.

Trial registration: Clinical Trials ID: NCT02711111.

Background/objectives: Third molar agenesis and palatally impacted canines (PICs) are two independent dental phenotypes with different developmental backgrounds. Isolated reports indicate a common genetic origin for both, however, current data is inconsistent. The aim of this study was to investigate the presence of third molar agenesis in individuals with PICs, compared to individuals without PICs.

Materials/methods: This retrospective case-control study comprised 310 individuals (188 females and 122 males), half of whom presented with unilateral or bilateral PICs. Individuals with other dental anomalies of known genetic origin were excluded. The association between PICs and third molar agenesis was assessed using four regression models, with PIC as the dependent variable and sex, age, and third molar agenesis as predictors. One model treated PIC as a nominal variable (pattern) and the other as ordinal (severity), and both were run testing either third molar agenesis severity or third molar agenesis patterns. All statistical tests were performed assuming a type-1 error of 5%.

Results: There was no significant association between canine impaction and third molar agenesis in any of the four regression models. Neither the severity nor the patterns of palatally impacted canines were associated with either the severity or the patterns of third molar agenesis (P > .05).

Limitations: Due to the common racial background of all participants, the results of this investigation might not be generalizable to the general population.

Conclusions/implications: Palatal canine impaction is not associated to third molar agenesis, after accounting for age, sex, and various patterns of PICs and third molar agenesis. These results indicate that these two dental phenotypes do not share a common biological mechanism for their occurrence.

Objectives: The aim of the study was to determine the genetic and environmental effects on transverse growth of craniofacial structures, within and between identical and fraternal twins.

Methods: The sample consisted of 142 children in total, divided into 29 pairs of monozygotic twins, 42 pairs of dizygotic twins, and 1 set of dizygotic triplets. Postero-anterior cephalometric radiographs were taken at the ages of 9, 12, and 15 years. Intercanine width, maxillary width, mandibular width, nasal width, and facial width variables were measured. The genetic and environmental components of variance were analyzed with structural equation modeling for multilevel mixed effects.

Results: Intercanine width was initially mainly characterized by a moderate genetic component at 9 years (53%), with environmental influence increasing at age 12 (36%) and peaking at 15 years (84%). Maxillary width was under strong genetic influence at 9 years (70%), with genetic influence remaining strong up to 15 years (73%). Mandibular width was under additive genetic influence at 9 years (76%), with dominant genetic influence remaining high at 15 years (81%). Nasal width was under strong additive genetic influence at 9 years (69%) but switched to increased environmental influence at 15 years (59%). Finally, facial width had a moderate genetic influence at 9 years (66%), which increased at 15 years (90%).

Limitations: This study included patients of European descent, which may limit the generalizability of the findings to other ethnic groups.

Conclusions: Although monozygotic and dizygotic twins share at least part of their genetic material, environmental factors accounted for about 10%-84% of variability at various ages, with intercanine width being most affected.