Progress in Orthodontics最新文献

Background: Clear aligners face biomechanical limitations in complex tooth movements, particularly first molar mesialization, despite attachment use. Finite element analysis (FEA) can elucidate optimal attachment designs for force delivery.

Objectives: To compare displacement patterns and stress distribution during maxillary first molar mesialization using four attachment designs via 3D FEA.

Methods: A maxillary model (MRI-derived) was created with periodontal ligament (PDL), alveolar bone, and clear aligner (0.75 mm thickness). Five scenarios were simulated: no attachment (Model-I), vertical rectangular (Model-II), horizontal rectangular (Model-III), optimized double semi-ellipsoidal (Model-IV), and Yin-Yang attachments (Model-V). Mesial displacement (0.5 mm) was applied, and deformation/stress were analyzed using ANSYS Workbench.

Results: Model-IV (optimized attachment) demonstrated the least first molar tipping, evidenced by its lowest total mesial crown displacement (0.319 mm), and provided the best mesiodistal control. Conversely, Model-I (no attachment) exhibited the highest tipping, with a total mesial crown displacement of 0.376 mm. Yin-Yang attachments (Model-V) significantly reduced buccal displacement by 92% compared to Model-I. Horizontal rectangular attachments minimized rotational movement.

Conclusions: Optimized double semi-ellipsoidal attachments provide superior first molar mesialization control, while Yin-Yang designs enhance buccal-lingual stability. Attachment geometry critically influences aligner efficacy.

The "periodontal ligament-periosteum (PDL-PS) sandwich hypothesis" has been proposed to explain the mechanism of bone recovery around roots moved outside their bony housing. This hypothesis suggests that the presence of the periosteum and periodontal ligament facilitates bone recovery in such cases. This retrospective case series examines three adult patients who developed iatrogenic dehiscences and fenestrations of the anterior teeth due to the placement of fixed lingual retainers after orthodontic treatment. Each patient then underwent orthodontic retreatment aimed at repositioning the roots back into the alveolar housing. Cone-beam computed tomography (CBCT) scans and intraoral photographs taken before (T2) and after (T3) retreatment were used to evaluate bone recovery. To test the PDL-PS sandwich hypothesis, predictions of bone recovery were made based on T2 parameters and the root movements achieved during retreatment. The observed bony recovery at T3 was then compared with these predictions. Roots that were partially or fully repositioned into the original alveolar housing exhibited partial to complete bony recovery. In contrast, teeth with minimal root movement back into bone showed limited or no recovery. In cases with pre-existing gingival recession, bone recovery occurred only apical to the areas of recession, even with favorable root movements. Additionally, the dimensions of the alveolar housing remained stable as roots moved through the alveolar bone, supporting the theory that roots move through alveolar bone, rather than with bone, in adults. These findings highlight the need for evidence-based clinical strategies to guide the management of inadvertent tooth movement caused by orthodontic appliances or retainers, with particular attention to the potential for bone recovery when repositioning teeth into their original alveolar housing.

Background: Maxillary 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).

Methods: This 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.

Results: The 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.

Conclusions: Custom 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.

Background: The 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 methods: A 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.

Results: After 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.

Conclusions: The 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.

Objective: There is a lack of studies on patient-reported outcomes in orthodontics. The aim of this study was to evaluate the changes in patient-reported chief complaints during orthognathic surgery treatment.

Materials and methods: Patients undergoing orthognathic surgery at the University Hospital Münster between 2019 and 2023 were eligible for inclusion in this prospective cohort study. Patient-reported chief complaints were recorded on visual analogue scale (VAS) forms before treatment ([Formula: see text]), and reevaluated after presurgical orthodontic treatment ([Formula: see text]), and 6-9 months after surgery ([Formula: see text]). Chief complaints were grouped into three main categories (pain, function, aesthetics) and ten subcategories, and their intensity was quantified over time.

Results: A total of 217 out of 386 recruited patients (56%) completed all study assessments and were included in the final analysis (female/male = 126/91, median age 24.1 years). Dental function, facial aesthetics, and dental aesthetics were the most frequently reported complaints at [Formula: see text]. At [Formula: see text], there was a statistically significant improvement in dental aesthetics. There was a statistically significant reduction in the intensity of each of the 10 subcategories from [Formula: see text] to [Formula: see text].

Conclusion: Orthognathic surgery patients most frequently report dental function, facial aesthetics, and dental aesthetics as their chief complaints, and these complaints were improved significantly after treatment.

Clinical relevance: The improvement in patient-reported chief complaints can be used to inform patients prior to treatment.

Background: The angulation of third molars is a critical factor influencing the likelihood of impaction. Orthodontic premolar extractions have been hypothesized to affect the eruption path of developing third molars by modifying available space and mesial drift patterns.

Objective: This systematic review and meta-analysis aimed to assess whether premolar extraction during orthodontic treatment alters the angulation of developing third molars compared to non-extraction protocols.

Eligibility criteria: Observational studies comparing angular measurements of third molars between extraction and non-extraction orthodontic treatments were included. Studies without a control group or adequate cephalometric data were excluded.

Information sources: A comprehensive literature search was conducted across two electronic databases (MEDLINE, Scopus) up to November 2024, following PRISMA 2020 guidelines.

Risk of bias and synthesis of results: Risk of bias was evaluated independently by two reviewers using the ROBINS-I tool. A random-effects meta-analysis was conducted, and the certainty of the evidence was assessed using the GRADE approach.

Results: Nine studies (865 participants) were included. For mandibular third molars, extraction was significantly associated with improved angulation (SMD = - 0.37; 95% CI: - 0.59 to - 0.15; p = 0.004). Significant differences were found in M3L/M2L (MD = - 1.31; 95% CI: - 1.76 to - 0.85; p = 0.003) and M3L/PP (MD = - 4.85; 95% CI: - 8.50 to - 1.21; p = 0.02). No statistically significant difference was observed in the M3L/MP angle. In the maxilla, only the M3U-PP angle showed a significant change (MD = - 5.79; 95% CI: - 11.53 to - 0.04; p = 0.049). Meta-regression revealed no association with age, sex, or premolar type. Certainty of evidence ranged from low to moderate.

Background: Skeletal Class II malocclusion is commonly treated using mandibular advancement appliances during growth. Evaluating the comparative effectiveness of different appliances can help optimize treatment outcomes.

Objectives: This study aimed to compare dental and skeletal outcomes of Class II malocclusion treatment using Herbst and PowerScope appliances in conjunction with fixed orthodontic therapy.

Methods: This retrospective comparative study included 46 consecutively treated patients in two university clinics: 26 with PowerScope and 20 with Herbst MiniScope. CBCT scans were obtained before and after treatment. Skeletal and dental changes were analyzed using maxillary and mandibular voxel-based regional superimpositions and cranial base registrations, aided by AI-based landmark detection. Measurement bias was minimized through the use of a calibrated, blinded examiner. No patients were excluded from the analysis. Due to the study's retrospective nature, no prospective registration was performed; the institutional review board granted ethical approval.

Results: The Herbst group showed greater anterior displacement at B-point and Pogonion than PowerScope (2.4 mm and 2.6 mm, respectively). Both groups exhibited improved maxillomandibular relationships, with PowerScope's SNA angle reduced and Herbst's SNB increased. Vertical skeletal changes were observed at points A, B, and Pog in both groups. Herbst also resulted in less lower incisor proclination and more pronounced distal movement of upper incisors.

Conclusion: Both appliances effectively corrected Class II malocclusion. Herbst promoted more pronounced skeletal advancement, while PowerScope induced greater dental compensation. These findings may be generalizable to similarly aged Class II patients in CVM stages 3-4.