Clear aligner treatment is a novel technique in current orthodontic practice. Distinct from traditional fixed orthodontic appliances, clear aligners have different material features and biomechanical characteristics and treatment efficiencies, presenting new clinical challenges. Therefore, a comprehensive and systematic description of the key clinical aspects of clear aligner treatment is essential to enhance treatment efficacy and facilitate the advancement and wide adoption of this new technique. This expert consensus discusses case selection and grading of treatment difficulty, principle of clear aligner therapy, clinical procedures and potential complications, which are crucial to the clinical success of clear aligner treatment.
Humans ; Consensus ; Orthodontic Appliance Design ; Orthodontic Appliances, Removable ; Tooth Movement Techniques/methods* ; Malocclusion/therapy* ; Orthodontics, Corrective/instrumentation*

Class Ⅱ malocclusion is a common orofacial deformity that could harm the facial esthetics and oral function. Two-stage treatment strategy always applies to functional and skeletal (mild and moderate) class Ⅱ malocclusion with man-dibular retrognathism in teenagers. Traditional functional orthopedic appliances are less comfortable and inconvenient to correct the dental arches, making the treatment duration long. With the rapid progress of digital technology and material science, functional clear aligners that offer comfort have emerged. Functional clear aligners can combine orthopedic and orthodontic treatments to correct the jaw relationship and align the dental arch, thereby shortening the treatment duration. This paper emphasizes the treatment key points, and clinical experience of using functional clear aligners.
Adolescent ; Esthetics, Dental ; Humans ; Malocclusion ; Malocclusion, Angle Class II ; Orthodontic Appliance Design ; Tooth Movement Techniques

No abstract available.
Malocclusion, Angle Class II ; Orthodontic Appliance Design ; Orthodontic Appliances ; Tooth Movement Techniques

Patients who have a moderate periodontitis with pathologic tooth migration of maxillary incisors, it is necessary not only periodontal treatment for reduce periodontal inflammation, but also orthodontic treatment to teeth repositioning. For orthodontic treatment, it is necessary to apply less force and careful considerations of the center of resistance of the tooth and optimal force of tooth movement. At this time, the segmental arch applied only to the target teeth, is more effective and predictable, because applied force and direction can be controlled. In addition, to design the orthodontic appliance that can prevent the unwanted tooth movement that used as an anchorage is important. In recent years, various types of skeletal anchorage system have been used for preventing loss of the anchorage. We reported the patient who had extruded maxillary central incisor due to pathologic tooth migration, treated by a successful periodontal-orthodontic multidisciplinary treatment using an orthodontic appliance designed to apply less traumatic force and reduce an anchorage loss.
Humans ; Incisor ; Inflammation ; Orthodontic Appliance Design ; Orthodontic Appliances ; Orthodontic Wires ; Periodontitis ; Tooth ; Tooth Migration ; Tooth Movement

OBJECTIVES: To observe the surface characteristics and mechanical behavior of retrieved microimplants under clinically simulating experimental conditions and to investigate the feasibility of reuse of microimplants. MATERIALS AND METHODS: The microimplants, inserted at different angles, were retrieved from the patients (RMIP) and the artificial bone (RMIA). Surface characteristics, including morphologic changes of tips and thread edges, length reduction, and surface compositional variation, were evaluated using a field emission scanning electron microscope, a stereoscopic microscope, and energy-dispersive X-ray spectroscopy, respectively. Mechanical behavior comprising maximum insertion torque (MIT) and insertion time was tested with the artificial bone under clinically simulating conditions. RESULTS: The tips and thread edges were worn out to various degrees in retrieved microimplants and thin deposits were observed on the surface in the RMIP group. Traces of foreign elements, such as iron, sulphur, and calcium, were detected on the surface of RMIP. Both MIT and insertion time of retrieved microimplants were increased compared to their initial use, and were much greater in RMIP. The increases of MIT were seen in all groups inserted at the insertion angle of 45° compared with 90°, although the differences were not statistically significant. CONCLUSIONS Retrieved microimplants exhibited different degrees of changes on surface characteristics and mechanical behavior, with more changes in RMIP. The reuse of microimplants for immediate relocation in the same patient may be acceptable; however, postponed relocation and allogeneic reuse of microimplants are not recommended in clinical practice.
Adolescent ; Adult ; Dental Implants ; Female ; Humans ; Male ; Middle Aged ; Orthodontic Anchorage Procedures ; Orthodontic Appliance Design ; Stress, Mechanical ; Surface Properties ; Young Adult

No abstract available.
Tooth Movement Techniques ; Orthodontic Appliance Design ; Malocclusion, Angle Class II ; Orthodontic Appliances

OBJECTIVEThis study investigated the influence of Hawley retainer and vacuum-formed retainer on the articu-lation of Chinese speech of adult orthodontic patients.

METHODSA total of 20 volunteers were recruited in this randomized controlled trial in accordance with the inclusion criteria. Participants were randomly distributed into two groups, namely, the Hawley retainer group and the vacuum-formed retainer group. Speech performance was evaluated at the following time inter-vals: before wearing retainers (T0), immediately after wearing both upper and lower retainers (T1), 24 h later (T2), 1 week later (T3), and 1 month later (T4). The phonetic parameters were acquired through the use of computer-based voice analysis software Praat version 5.4.21, and the final data were analyzed using SPSS 19.0.

RESULTSBoth retainers can influence the phonetic parameters of vowels /e/, /i/, and /ü/ and consonants /s/, /f/, /x/, /t/, /j/, and /q/. However, the Hawley retainer showed a more remarkable effect on the articulation of Chinese speech, and the distortion of /i/, /ü/, and /s/ sounds can last for more than 1 month. Nevertheless, the recovery period of the patients' phonetic function in the vacuum-formed retainer group was within 1 month.

CONCLUSIONSBoth retainers can induce distortion of some Chinese vowels and consonants in the speech of adult orthodontic patients, but the Hawley retainer can more significantly influence the articulation of Chinese speech than vacuum-formed retainer.
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OBJECTIVEFrictions of Lock-loose brackets with ligated main wings or all six wings were measured as they slid along archwires in dry and artificial saliva environments. The Lock-loose brackets were then compared with traditional brackets and self-ligating brackets.

METHODSThe surface states of the stainless steel archwires were observed with atomic force microscopy before and after mechanical traction. The Lock-loose brackets, traditional brackets, and self-ligating brackets used in this study were composed of 0.406 4 and 0.457 2 mm stainless steel round archwires and 0.457 2 mm x 0.634 9 mm and 0.482 6 mm x 0.634 9 mm stainless steel rectangular archwires. Two different ligating methods were applied to the Lock-loose brackets, i.e., main wings ligated and all six wings ligated. Frictions were measured by using an electronic universal testing machine.

RESULTSNo significant differences were found between the roughness of different archwires before and after mechanical traction in different brackets (P > 0.05). When the main wings of the Lock-loose brackets were ligated, the frictions of the four different stainless steel archwires were close to zero, and the difference with frictions of traditional brackets was significant (P < 0.05). When using 0.457 2 mm x 0.634 9 mm rectangular archwires, maximum friction (P < 0.05; significantly different from those of other brackets) was reached when all six wings of the Lock-loose brackets were ligated. Frictions in the dry state were higher than those in the wet state (P < 0.05).

CONCLUSIONThe Lock-loose brackets can adjust the friction efficiently with different ligating methods, thus solving the problem of low friction and strengthening anchorage.

Humans ; Malocclusion, Angle Class I ; therapy ; Orthodontic Appliance Design

Combined with a case, the mechanical analysis and clinical application of micro-implant combining with utility arch were introduced in this paper.
Humans ; Maxilla ; Molar ; Orthodontic Appliance Design ; Orthodontic Wires ; Tooth Movement Techniques