Journal of Orthodontics最新文献

Background: Identification of tooth ankylosis before comprehensive orthodontic treatment can be challenging. This case series illustrates different presentations of tooth ankylosis, the importance of early diagnosis, the use of surgical luxation to aid orthodontic alignment of ankylosed teeth and its sequelae.

Case presentation: All three cases were adolescents: a 14-year-old girl with a highly placed upper left lateral incisor and history of general anaesthesia; a 14-year-old boy with an impacted upper right first premolar and history of dental trauma; and a 13-year-old girl with an infraoccluded upper left central incisor with history of replantation due to avulsion. Iatrogenic malocclusion developed from attempts to align these ankylosed teeth. Subsequently, surgical luxation was performed, and the ankylosed teeth were successfully aligned. However, it was associated with pulp calcification, root resorption and recurrence of ankylosis.

Conclusion: Surgical luxation and orthodontic alignment of ankylosed teeth can be considered a useful short-term solution to delay the need of surgical removal and teeth replacement.

Tooth transposition is the positional interchange of two adjacent teeth, which may be incomplete or complete. The root apex may remain in a normal position despite a severely displaced crown. The aim of this paper is to provide a literature review on the incidence, aetiology and treatment options for pseudo-transposed mandibular incisors. A case series is also presented highlighting the various management techniques that have been utilised in treating five cases of pseudo-transposed mandibular lateral incisors.

Objective: To assess the accuracy of cone-beam computed tomography (CBCT)-synthesised lateral cephalograms (CSLCs) compared with conventional lateral cephalograms for cephalometric analysis in human participants and skull models.

Methods: The authors performed a search of PubMed, Scopus, Google Scholar and Embase databases on 4 October 2021. Included studies met the following criteria: published in English; compared conventional lateral cephalograms and CSLCs; assessed hard- and soft-tissue landmarks; and were performed on human or skull models. Data extraction from eligible studies was performed by two independent reviewers. The quality of evidence was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist tool - diagnostic accuracy studies.

Results: A total of 20 eligible articles were included in this systematic review. Of these 20 studies, 17 presented with a low risk of bias, while three were found to have a moderate risk of bias. Hard- and soft-tissue analyses were evaluated for each imaging modality. The findings reveal that CSLCs are accurate and comparable to conventional lateral cephalograms for cephalometric analysis and demonstrate good inter-observer reliability. Four studies reported a higher accuracy with CSLCs.

Conclusion: Overall, the diagnostic accuracy and reproducibility of CSLCs were comparable to conventional lateral cephalograms in cephalometric analysis. It is justified that patients who have an existing CBCT scan do not need an additional lateral cephalogram, minimising unnecessary radiation exposure, expenses and time for the patient. Larger voxel sizes and low-dose CBCT protocols can be considered to minimise radiation exposure.

Registration: This study was registered with PROSPERO (CRD42021282019).

Background: The accuracy of artificial intelligence (AI) in treatment planning and outcome prediction in orthognathic treatment (OGT) has not been systematically reviewed.

Objectives: To determine the accuracy of AI in treatment planning and soft tissue outcome prediction in OGT.

Design: Systematic review.

Data sources: Unrestricted search of indexed databases and reference lists of included studies.

Data selection: Clinical studies that addressed the focused question 'Is AI useful for treatment planning and soft tissue outcome prediction in OGT?' were included.

Data extraction: Study screening, selection and data extraction were performed independently by two authors. The risk of bias (RoB) was assessed using the Cochrane Collaboration's RoB and ROBINS-I tools for randomised and non-randomised clinical studies, respectively.

Data synthesis: Eight clinical studies (seven retrospective cohort studies and one randomised controlled study) were included. Four studies assessed the role of AI for treatment decision making; and four studies assessed the accuracy of AI in soft tissue outcome prediction after OGT. In four studies, the level of agreement between AI and non-AI decision making was found to be clinically acceptable (at least 90%). In four studies, it was shown that AI can be used for soft tissue outcome prediction after OGT; however, predictions were not clinically acceptable for the lip and chin areas. All studies had a low to moderate RoB.

Limitations: Due to high methodological inconsistencies among the included studies, it was not possible to conduct a meta-analysis and reporting biases assessment.

Conclusion: AI can be a useful aid to traditional treatment planning by facilitating clinical treatment decision making and providing a visualisation tool for soft tissue outcome prediction in OGT.

Registration: PROSPERO CRD42022366864.

Objective: To compare the three-dimensional (3D) effects of canine traction on the maxillary teeth when using two different traction methods, the continuous and the segmented arch wire techniques; then to test whether adding a transpalatal arch (TPA) would affect their response to traction.

Design: Finite element analysis.

Methods: A cone-beam computed tomography (CBCT) scan of a patient with bilateral palatally impacted canines was chosen, from which a 3D model was derived and imported into ABAQUS. Two arch wires were modelled, a continuous round one and a segmented rectangular one. Four models were obtained by adding a TPA to both techniques. A 100° imposed rotation was then applied at the intersection between the vertical loop and the horizontal segment of each wire. Initial displacement of the maxillary tooth in the labio-lingual and in the vertical directions was measured. The absolute maximum principal stress of the periodontal ligament (PDL) was also assessed.

Results: Traction using a continuous arch wire led to different movement patterns of all teeth, some of them were tipped in a labial direction while others were lingually tipped. Traction using a segmented arch wire resulted in a retroclination of the posterior teeth and a proclination of the anterior teeth with a high level of stress on the premolars' PDL. Adding the TPA only affected the displacement of the first molars. The right side showed a maximum displacement of the first premolar, while the left side showed it on the lateral. The total displacement on the right side was higher than the left side.

Conclusion: The segmented technique caused a uniform displacement of all teeth while the continuous one showed a non-uniform displacement. The angulation and position of the vertical loop affected the displacement of the maxillary teeth. The addition of a TPA acted only on the first molars.