Journal of the World Federation of Orthodontists最新文献

Background

This study aimed to examine how well patients can differentiate between orthodontists and dentists.

Methods

Four hundred patients who applied to the Ondokuz Mayıs University Faculty of Dentistry, Department of Oral and Maxillofacial Radiology between March and November of 2022 were queried regarding the difference between an orthodontist and a dentist via a face-to-face survey. The respondents were separated into the following two study groups: patients who had previously undergone orthodontic treatment and those who had not. Demographic data of the patients, such as age, sex, educational status, and monthly income, were also collected, and the effects of these factors on their doctor preferences were analyzed.

Results

The vast majority of respondents (>85%) thought that a dentist should be an orthodontic specialist to provide orthodontic treatment. Seven percent of patients chose to receive orthodontic treatment from a dentist. Patients who chose an orthodontist for their treatment were predominantly female and had a high income and a higher level of education. Patients who had a history of orthodontic treatment were better aware of the profession of orthodontics than those who did not.

Conclusions

The results indicated that the respondents did not fully understand the clear distinction between an orthodontist and a dentist. This outcome suggests that education concerning this issue is required.

Background

Bone age assessment, as an indicator of biological age, is widely used in orthodontics and pediatric endocrinology. Owing to significant subject variations in the manual method of assessment, artificial intelligence (AI), machine learning (ML), and deep learning (DL) play a significant role in this aspect. A scoping review was conducted to search the existing literature on the role of AI, ML, and DL in skeletal age or bone age assessment in healthy individuals.

Methods

A literature search was conducted in PubMed, Scopus, and Web of Science from January 2012 to December 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses–Extension for Scoping Reviews (PRISMA-ScR) and Joanna Briggs Institute guidelines. Grey literature was searched using Google Scholar and OpenGrey. Hand-searching of the articles in all the reputed orthodontic journals and the references of the included articles were also searched for relevant articles for the present scoping review.

Results

Nineteen articles that fulfilled the inclusion criteria were included. Ten studies used skeletal maturity indicators based on hand and wrist radiographs, two studies used magnetic resonance imaging and seven studies used cervical vertebrae maturity indicators based on lateral cephalograms to assess the skeletal age of the individuals. Most of these studies were published in non-orthodontic medical journals. BoneXpert automated software was the most commonly used software, followed by DL models, and ML models in the studies for assessment of bone age. The automated method was found to be as reliable as the manual method for assessment.

Conclusions

This scoping review validated the use of AI, ML, or DL in bone age assessment of individuals. A more uniform distribution of sufficient samples in different stages of maturation, use of three-dimensional inputs such as magnetic resonance imaging, and cone beam computed tomography is required for better training of the models to generalize the outputs for use in the target population.

Background

A finite element model was used to investigate the effect of different designs and thicknesses of orthodontic aligner margins on their biomechanical behavior.

Methods

A three-dimensional data set of an upper jaw was imported into the 3-matic software. The upper right central incisor tooth (Tooth 11) was separated from the remaining model, and its periodontal ligament and surrounding bone were designed. Aligners were designed with four different trimming lines (scalloped, straight, scalloped extended, straight extended), each with four different thicknesses (0.3, 0.4, 0.5, and 0.6 mm). The models were imported into a finite element package (Marc/Mentat). A linear elastic constitutive material model was applied. A facial 0.2 mm bodily malalignment of tooth 11 was simulated.

Results

The maximum resultant force was in the range of 1.0 N to 2.2 N. The straight trimming designs deliver higher resultant forces compared with scalloped trimming designs. Increasing the aligner thickness and/or extending the aligner edge beyond the gingival line leads to an increase in the resultant force. All designs showed an uneven distribution of the normal contact forces over the tooth surface with a predominant concentration toward the cervical third and distal third, particularly with the extended trimming designs. All designs showed uncontrolled tipping of the tooth.

Conclusions

Based on the current model outcomes, the use of a straight extended trimming line design for aligners is favored because of its positive impact on force distribution and, consequently, the control of tooth movement.

Clinical Relevance

These findings provide aligner companies and orthodontists a valuable biomechanical evidence and guidance to enhance control over tooth movement and therefore optimize treatment outcomes. This can be achieved by trimming the edges of aligners with a straight extended design and selecting the appropriate aligner thickness.

Aligner orthodontics has gained significant popularity as an alternative to traditional braces because of its aesthetic appeal and comfort. The biomechanical principles that underlie aligner orthodontics play a crucial role in achieving successful outcomes.

The biomechanics of aligner orthodontics revolve around controlled force application, tooth movement, and tissue response.

Efficient biomechanics in aligner orthodontics involves consideration of attachment design and optimized force systems. Attachments are tooth-colored shapes bonded to teeth, aiding in torque, rotation, and extrusion movements. Optimized force systems ensure that forces are directed along the desired movement path, reducing unnecessary strain on surrounding tissues.

Understanding and manipulating the biomechanics of aligner orthodontics is essential for orthodontists to achieve optimal treatment outcomes. This approach requires careful treatment planning, considering the mechanics required for each patient's specific malocclusion. As aligner orthodontics continues to evolve, advances in material science and treatment planning software contribute to refining biomechanical strategies, enhancing treatment efficiency, and expanding the scope of cases that can be successfully treated with aligners.

Background

This study aimed to compare the soft tissue effects of Herbst appliance in Class II malocclusion patients treated in three different craniofacial growth phases: prepubertal (PRE), circumpubertal (CIR), and postpubertal (POS).

Methods

In total, 95 patients with Class II Division 1 malocclusion previously treated with a Herbst appliance were analyzed. Through the cervical vertebral maturation stages method, patients were allocated into three groups depending on the growth craniofacial phase at the beginning of treatment: PRE, CIR, and POS. Seventeen cephalometric measures were evaluated from each lateral radiograph before and after Herbst therapy using the Radiocef 2 software (Radio Memory, Belo Horizonte). Intragroup and intergroup treatment changes were compared statistically using a paired t test and MANOVA test, respectively.

Results

Soft tissue thickness changes were related only to mandible; all three mandibular measurements (L1_LL, B_B’, and Pog_Pog’) showed thickening for the PRE group ranging from 0.92 mm (Pog_Pog’) to 2.02 mm (B_B’), and only lower lip thickened overtime for the POS group (L1_LL = 0.99 mm). Soft and hard tissue pogonion displaced anteriorly, but only the soft tissue showed differences among groups; PRE group presented more anterior displacement than POS group (3.61 mm and 1.39 mm, respectively). Hard and soft tissue facial convexity decreased more in the PRE and CIR groups than in the POS group. Mentolabial sulcus depth reduced more in the PRE (1.07 mm) and CIR (1.29 mm) groups than in the POS (0.55 mm) group. Horizontal movement of the skeletal and soft pogonion presented a moderate-high positive correlation (r = 0.783), and hard and soft facial convexity showed a moderate-low positive correlation (r = 0.403).

Conclusions

Herbst appliance therapy produces soft tissue improvements in the three phases of craniofacial growth, being greater in patients in the PRE and CIR phases.

Deep bite is usually treated by intrusion of the anterior teeth, extrusion of the posterior teeth, or a combination thereof. Various traditional methods have been used to correct deep bites, but they can cause negative side effects. Recently, temporary skeletal anchorage devices (TSADs) have been used to intrude the anterior teeth simply and efficiently without side effects. The amount of incisal exposure at rest should be considered as the first factor in determining which tooth segment should be intruded to correct a deep bite. The center of resistance of the anterior teeth should be considered to achieve the proper biomechanics when intruding them. The location of TSADs should be determined to ensure sufficient interradicular bone to achieve the desired tooth movement. Therefore, clinicians should understand the biomechanical and clinical considerations to correct a deep bite using TSADs.

Anterior open bite can be effectively treated nonsurgically via molar intrusion. This technique, involving the intrusion of posterior teeth using temporary skeletal anchorage devices, prompts counterclockwise rotation of the mandible. This rotation not only corrects anterior open bite but also contributes to a decrease in anterior facial height, improvements in lip incompetency, and forward movement of the chin. For successful outcomes, temporary skeletal anchorage devices, installed on both the buccal and palatal sides, must deliver equivalent intrusion force to the maxillary teeth. Treatment planning should consider factors such as skeletal discrepancies, vertical excess, incisor exposure, and configuration of the occlusal plane. Clinicians are advised to closely monitor periodontal changes and consider overcorrection to ensure lasting stability and maintenance of incisal overlap post-treatment.

This case report describes successful orthodontic retreatment for vertical control with nonextraction orthodontic therapy. A 31-year-old woman complained of anterior open bite and crowding. She had slightly protrusive lips but wanted to correct her malocclusion without extraction. Two palatal temporary skeletal anchorage devices were used for the distalization of the maxillary arch along with posterior intrusion. Mandibular distalization was performed with Class III elastics. The duration of active treatment was 22 months. The plain and efficient mechanics used contributed to the effective distalization of both arches, the intrusion of the maxillary posterior teeth, and favorable profile changes. The results were still stable at the five-year follow-up period.