Turkish Journal of Orthodontics最新文献

Objective: This study aimed to evaluate the micro-implant safest insertion site on the mandibular buccal shelf (MBS) without compromising the integrity of the mandibular canal (MC).

Methods: This retrospective investigation included cone-beam computed tomography (CBCT) of 96 Portuguese patients (58 females and 38 males, average age of 25.5±10.2 years). Measurements were taken in four bilateral MBS sites buccal to the mandibular second molar; tangent to the distal surface (7D), distobuccal cusp tip (7CD), buccal groove (7S) and mesiobuccal cusp tip (7CM). The transversal MBS midpoint was also determined, and the maximum angulation from the transversal MBS midpoint was extracted relative to the true vertical plane. Subsequently, the distance from the MBS midpoint to the MC was calculated at this angulation. Descriptive and inferential statistical analyses were performed at p<0.05.

Results: Significant correlations were observed among several variables and age, sex and bilateral asymmetry (p<0.05). The MBS transversal width and the distance from the MBS midpoint to the MC progressively increased in the posterior direction while the angulation decreased.

Conclusion: The most appropriate micro-implant insertion location compared to the other MBS investigated sites, in the absence of impacted third molars, is adjacent to the distal surface of the second molar. This finding is consistent across all age groups, sexes, and insertion sides. However, due to the demonstrated variability, taking a CBCT scan prior to mini-implant insertion might be considered to minimize the risk of injury to the inferior alveolar nerve.

Objective: The aim of this study was to evaluate the surface hardness, surface roughness, and chemical structure changes of four vacuum-formed retainer (VFR) materials after thermoforming.

Methods: Four groups of VFR materials were evaluated: Taglus, Lumex-G, Atmos, and Duran. Each group consisted of 12 samples (n=12) that were thermoformed according to the manufacturer's guidelines. Surface roughness was measured using a high-precision profilometer, and hardness was assessed with a micro-Vickers hardness tester. Chemical structure analysis was conducted using Fourier transform infrared spectroscopy (FTIR), and surface morphology was examined using scanning electron microscopy (SEM).

Results: Hardness measurements demonstrated a general decrease across all groups following thermoforming. After thermoforming, surface roughness increased significantly in the Taglus and Lumex-G groups, whereas the Atmos and Duran groups maintained greater surface stability. FTIR demonstrated that all materials retained their chemical stability, and no significant changes in functional groups were detected. SEM results revealed more pronounced surface irregularities in the Taglus and Lumex-G groups.

Conclusion: Polyethylene terephthalate glycol copolyester-based materials with high surface homogeneity, such as Atmos and Duran, may be recommended for clinical use due to their superior surface stability and chemical resilience. By contrast, the surface irregularities observed in Taglus and Lumex-G may compromise their long-term clinical performance.

Objective: To evaluate the positioning of brackets in customized and conventional bonding methods in accordance with Andrews' approach to bracket placement.

Methods: Twenty-six patients were enrolled; 11 were treated with the Insignia system and 15 with Kalange's method. Crown length was measured on a digital diagnostic model and the facial axis (FA) point was calculated. After leveling and alignment, a new digital model was created, and the bracket position was measured along the vertical axis. The distance between the bracket position and the FA point was calculated, and the deviation was determined according to Andrews' method. Teeth with significant deviation (TSD), i.e., >0.5 mm, were identified. Frequencies and percentages of TSD were calculated.

Results: The TSD percentage was 56.65% in the Insignia group and 69.5% in the modified Kalange group; the difference between groups was significant (p=0.003). The anterior and posterior regions differed significantly within groups: in the Insignia group, this difference was observed in the maxilla (p=0.002), whereas in the modified Kalange group it was observed in both the mandible and maxilla (P < 0.001). In both groups, the anterior TSD percentage was higher than the posterior TSD percentage in both the maxilla and the mandible. The deviation was predominantly occlusal or incisal: Insignia group, 86.9%; modified Kalange group, 97.6%.

Conclusion: In the Insignia system and Kalange's method, brackets are positioned more incisally/occlusally relative to Andrews' FA point. In both methods, anterior brackets are positioned more incisally than posterior brackets.

Objective: This study aimed to investigate the skeletal and dental effects of the maxillary skeletal expander (MSE) using cone beam computed tomography (CBCT) images analyzed in the coronal zygomatic and axial palatal sections (APS).

Methods: Pre- and post-expansion CBCT images of 18 subjects (10 females and 8 males) aged 12-16 years with maxillary transverse deficiency who were treated with MSE 2 were included in this retrospective study. In the coronal zygomatic section (CZS), upper interzygomatic distance and lower interzygomatic distances (LID), orbital distance (OD), alveolar distances (AD), and dental distances (DD), as well as nasal cavity width (NCW) and molar basal bone angle, were assessed. In the APS, the separation between the anterior nasal spine (ANS) and posterior nasal spine (PNS) was assessed. All measurements were performed using OnDemand3D software. Pre- and post-expansion treatment changes were compared using paired t-tests, with statistical significance set at p<0.05.

Results: In the CZS, a pyramidal skeletal expansion pattern was observed, with the greatest increase in DD (R: 2.83 mm, L: 3.18 mm), followed by AD (R: 1.63 mm, L: 1.97 mm), NCW (R: 1.66 mm, L: 2.28 mm), LID (R: 1.48 mm, L: 1.92 mm), and OD (R: 0.42 mm, L: 0.56 mm). Along with greater skeletal expansion, slightly reduced dental tipping and minimal alveolar bone bending were observed. In the APS, a nearly equal separation was observed at both the ANS (R: 1.79 mm, L: 2.46 mm) and PNS (R: 1.85 mm, L: 2.49 mm), indicating a parallel split of the midpalatal suture. Furthermore, among the 36 pterygopalatine sutures examined, only three showed separation between the medial and lateral pterygoid processes.

Conclusion: MSE 2 application provides more favorable skeletal outcomes reduces dentoalveolar side effects, and results in a more parallel midpalatal suture split.

Objective: To evaluate and compare the effects of low-intensity pulsed ultrasound (LIPUS), low-level laser therapy (LLLT), and their combined effects on sutural bone regeneration during rapid maxillary expansion (RME) of rats.

Methods: Twenty-eight Sprague-Dawley rats were randomly assigned to four groups: LLLT group, LIPUS group, combination group, and control group. RME was performed on all groups for 11 days. The Both LLLT and LIPUS groups received their respective therapies (30 J/cm²), while the combination group received both therapies, each at 30 J/cm². All treated rats received their doses on days 0, 4, and 8 and were sacrificed on day 11. Numbers of osteoblasts, capillaries, and osteoclasts were counted, and suture widths and areas of newly formed bone were measured histomorphometrically. General and cellular immunoreactivity of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and osteopontin (OPN) was evaluated by immunohistochemistry.

Results: The number of osteoblasts was significantly higher in the combination group than in the control group (p<0.05). The combination group showed the highest general BMP-2 immunoreactivity and cellular VEGF immunoreactivity among all groups, and exhibited increased cellular OPN immunoreactivity compared with the control group (p<0.05). Both the area of newly formed bone (p<0.05) and suture width (p<0.01) were significantly greater in the LIPUS group than in the LLLT group.

Conclusion: LIPUS is a more effective adjuvant therapy than LLLT for increasing sutural bone formation during RME. Combined therapy with LIPUS and LLLT has a synergistic effect and accelerates sutural bone regeneration by enhancing cellular activation more than either LIPUS or LLLT alone.

Objective: The aim of this study was to compare the effects of two thermoforming machines on the gap width and thickness of passive aligners with the same nominal thickness from different manufacturers by using nano-computed tomography (CT).

Methods: An intraoral scan of a patient with Angle's Class I malocclusion was conducted, and a 3D maxillary arch model was printed. The aligners (n=16) were fabricated using two thermoforming machines: Ministar machine (n=8) and a Plastpress machine (n=8). Each group was subdivided on the basis of aligner material: polyethylene terephthalate glycol (PET-G) (Group A) and thermoplastic polyurethane (TPU) (Group B). Sheets with a nominal thickness of 0.75 mm were used. Nano-CT was performed, and the rendered 3D models were sliced into central incisor, canine, and molar regions to assess gap width and aligner thickness in the buccal, incisal, and palatal regions.

Results: Comparing thermoforming machines, PET-G (p=0.010) and TPU (p=0.004) aligners showed significant differences in gap width in the molar region. Similar results were found for aligner thickness (TPU, p=0.05; PET-G, p=0.004). Comparing PET-G and TPU sheets thermoformed via the same machine, significant differences were observed only in the molar region (p=0.004), with no differences in the canine and incisor regions. Adaptation in the anterior region was greater than in that of the posterior region, whereas aligner thickness increased from posterior to anterior.

Conclusion: Aligner material type significantly affected gap width and thickness only in the molar region, whereas the specific thermoforming machine did not substantially affect these characteristics.

Objective: The present study aimed to investigate changes in cervical lordosis, neck disability, and postural balance through static and dynamic tests in patients with skeletal Class III malocclusion who were treated with bimaxillary orthognathic surgery.

Methods: In this prospective observational study, 18 patients (mean age 23.3±5.4 years) with maxillary retrusion and mandibular prognathia were treated by bimaxillary orthognathic surgery. Static and dynamic balance tests were recorded with the Kinesthetic Ability Trainer preoperatively (T1) and at least 2 months postoperatively (T2). Cervical lordosis angle (C2-C7) was evaluated with the posterior tangent method on the lateral cephalometric films taken at T1 and T2. Neck disability and pain were assessed through questionnaires at both time points.

Results: The median follow-up time was 5.8 months. The mean maxillary advancement was 4.0 mm at point A (p=0.001). The mean mandibular setback was 2.4 mm at point B (p=0.166). An 8.4 mm maxillomandibular correction was observed according to the Wits appraisal (p=0.001). Static and dynamic balance tests, cervical lordosis angle, neck disability, and pain revealed no significant change between T1 and T2. No statistically significant correlation was observed between surgical movements and changes in the cervical lordosis angle.

Conclusion: Orthognathic surgical correction of skeletal Class III malocclusion, -primarily through maxillary advancement with less mandibular setback- did not lead to significant changes in cervical lordosis, neck disability, or postural balance as assessed through static and dynamic tests.

Objective: To compare the effects of the face mask and Carrière Motion^® III appliance in growing patients with Class III malocclusion associated with maxillary retrognathia. The null hypothesis was that both appliances, applied after rapid maxillary expansion, would have similar effects.

Methods: Skeletal, dental, and soft tissue changes were evaluated using lateral cephalometric radiographs of 26 patients aged 6-9 years, taken before (T0) and after treatment (T1). Cephalometric analyses were performed using Nemoceph^® software (NEMOTEC, Madrid, Spain). Statistical analyses were carried out with MedCalc version 12.7.7 (MedCalc Software bvba, Ostend, Belgium) with significance set at p<0.05.

Results: SNA°, A-NasionPerp, and Co-A increased significantly in both groups, with no significant intergroup difference. Co-Gn, Wits, ANB°, S-N, and the articular angle also increased significantly in both groups. SNB° decreased significantly only in the Carrière Motion^® III group. Greater anterior maxillary rotation occurred with the face mask, while reduced rotation was observed with the Carrière Motion^® III. Lower facial height decreased slightly but significantly in the Carrière Motion^® III group, and increased in the face mask group. Overjet and molar relationship improved significantly in both groups. The UL-E line distance decreased in the face mask group, while the Carrière Motion^® III showed no significant soft tissue changes.

Conclusion: The null hypothesis was rejected. The two appliances had different effects; however, the Carrière Motion^® III proved effective for early Class III treatment and may be considered an alternative, particularly for patients with social concerns about extraoral traction.

Objective: This study aimed to use finite element analysis to evaluate the effects of acrylic HYRAX and hybrid HYRAX devices in the treatment of rapid maxillary expansion (RME), particularly on the orbital compartments.

Methods: In the present study, a craniofacial model was developed utilizing computed tomography data obtained from the visible human project. A total of four distinct models were generated by designating the sutures in the adult variation as closed and those in the non-adult variation as open while incorporating both expansion devices into the model. Both acrylic and hybrid device models were subjected to expansion forces of 0.25 mm and 5 mm, yielding eight distinct scenarios for comprehensive analysis.

Results: Significant stress and displacement were observed, particularly around the orbital compartments in all scenarios. Displacement decreased with increased sutural ossification and the resulting stresses demonstrated elevation. In adult models, the hybrid device generated reduced stress, especially around the orbital compartments.

Conclusion: Based on these findings, it is proposed that the orbital compartments may serve as a clinically relevant site for measuring the increased intracranial pressure during RME treatment. To prevent possible side effects, RME should be performed at an early age, and if ossification is suspected to be increased, bone-supported expansion devices are recommended.

Clear aligner therapy has gained significant popularity in orthodontics due to its aesthetic advantages and patient comfort. However, achieving complex and precise tooth movements with aligners often necessitates the use of auxiliary features such as attachments. This review explores the biomechanical role of attachments in clear aligner therapy and evaluates their effectiveness in facilitating various orthodontic tooth movements, including rotation, extrusion, intrusion, torque, distalization, and arch expansion. Attachments serve as critical components for enhancing force delivery, ensuring aligner retention, and improving the predictability of tooth movement. The morphology, quantity, and positioning of attachments have a direct impact on movement efficiency, patient comfort, and overall treatment success. The article highlights the importance of selecting appropriate attachment shapes (such as rectangular, ellipsoidal, or optimized designs) based on the intended movement. It emphasizes the relevance of strategic placement relative to the tooth's center of resistance. Furthermore, for cases requiring complex or combined movements, strategies such as phased treatment planning and the use of multiple or combined attachments are discussed. While optimized attachments have shown biomechanical advantages in some movements, clinical studies suggest that in many instances, their superiority over conventional attachments is not statistically significant, leaving the choice of design largely to clinician preference. This review underscores the necessity of individualized attachment planning to optimize biomechanics and improve treatment outcomes in aligner-based orthodontics.