The consequences of living with a severe malocclusion: A review of the literature

Orthodontic and Orthognathic Surgical Treatment in a Patient with a Large Lymphatic Malformation of the Face: A Case Report

Lymphatic malformations (LMs) are congenital abnormalities in the development of the lymphatic system. They can damage other structures including the airway, blood vessels, nerves, or bones. LMs of the face can result in malocclusion, and many patients with LMs of the face require orthognathic surgery to correct the malocclusion. Surgery-first is a treatment modality which should be considered for individuals with LMs and is a protocol in which orthognathic surgery is performed prior to orthodontic treatment. This case report describes surgery-first and subsequent orthodontic treatment in a patient with a class III malocclusion due to a large facial LM.

Deep learning for 3D cephalometric landmarking with heterogeneous multi-center CBCT dataset

Cephalometric analysis is critically important and common procedure prior to orthodontic treatment and orthognathic surgery. Recently, deep learning approaches have been proposed for automatic 3D cephalometric analysis based on landmarking from CBCT scans. However, these approaches have relied on uniform datasets from a single center or imaging device but without considering patient ethnicity. In addition, previous works have considered a limited number of clinically relevant cephalometric landmarks and the approaches were computationally infeasible, both impairing integration into clinical workflow. Here our aim is to analyze the clinical applicability of a light-weight deep learning neural network for fast localization of 46 clinically significant cephalometric landmarks with multi-center, multi-ethnic, and multi-device data consisting of 309 CBCT scans from Finnish and Thai patients. The localization performance of our approach resulted in the mean distance of 1.99 ± 1.55 mm for the Finnish cohort and 1.96 ± 1.25 mm for the Thai cohort. This performance turned out to be clinically significant i.e., ≤ 2 mm with 61.7% and 64.3% of the landmarks with Finnish and Thai cohorts, respectively. Furthermore, the estimated landmarks were used to measure cephalometric characteristics successfully i.e., with ≤ 2 mm or ≤ 2° error, on 85.9% of the Finnish and 74.4% of the Thai cases. Between the two patient cohorts, 33 of the landmarks and all cephalometric characteristics had no statistically significant difference (p < 0.05) measured by the Mann-Whitney U test with Benjamini-Hochberg correction. Moreover, our method is found to be computationally light, i.e., providing the predictions with the mean duration of 0.77 s and 2.27 s with single machine GPU and CPU computing, respectively. Our findings advocate for the inclusion of this method into clinical settings based on its technical feasibility and robustness across varied clinical datasets.

Redefining precision and efficiency in orthognathic surgery through virtual surgical planning and 3D printing: a narrative review

Orthognathic surgery, essential for addressing jaw and facial skeletal irregularities, has historically relied on traditional surgical planning (TSP) involving a series of time-consuming steps including two-dimensional radiographs. The advent of virtual surgical planning (VSP) and 3D printing technologies has revolutionized this field, bringing unprecedented precision and customization to surgical processes. VSP facilitates 3D visualization of the surgical site, allowing for real-time adjustments and improving preoperative stress for patients by reducing planning time. 3D printing dovetails with VSP, offering the creation of anatomical models and surgical guides, enhancing the predictability of surgical outcomes despite higher initial setup and material costs. The integration of VSP and 3D printing promises innovative and effective solutions in orthognathic surgery, surpassing the limitations of traditional methods. Patient-reported outcomes show a positive post-surgery impact on the quality of life, underlining the significant role of these technologies in enhancing self-esteem and reducing anxiety. Economic analyses depict a promising long-term fiscal advantage with these modern technologies, notwithstanding the higher initial costs. The review emphasizes the need for large-scale randomized controlled trials to address existing research gaps and calls for a deeper exploration into the long-term impacts and ethical considerations of these technologies. In conclusion, while standing on the cusp of a technological renaissance in orthognathic surgery, it is incumbent upon the medical fraternity to foster a collaborative approach, balancing innovation with scrutiny to enhance patient care. The narrative review encourages the leveraging of VSP and 3D printing technologies for more efficient and patient-centric orthognathic surgery, urging the community to navigate uncharted territories in pursuit of precision and efficiency in the surgical landscape.

Stress distribution of the modified clear twin-block aligner on the temporomandibular joint, alveolar bone and teeth: A finite element analysis

OBJECTIVE

The modified clear twin-block aligner (CTBA) was developed to provide a mandibular advancement appliance for the treatment of mandibular retrognathia. The objective of this study was to analyse the stress distribution changes of CTBA with 45°, 60° and 70° bite blocks.

MATERIAL AND METHODS

A three-dimensional model of the craniomaxillofacial bones and teeth was generated from a spiral computed tomography (CT) scan. The models of the articular disc, capsule, periodontal ligament and CTBA were constructed mathematically. After assigning the appropriate material properties and the boundary condition using ABAQUS software, we simulated the CTBA with different bite blocks to analyse the mechanical effects.

RESULTS

In the temporomandibular joint (TMJ) region, the posterior aspect of the condyle and glenoid fossa experienced tensile stress that was approximately about 22 times greater at 70° than at 45°. The Von Mises stress distribution on the articular disc tended to be uniform. The strain direction of the condyle was backward. In the maxillary bone, the stress on the labial alveolar bone was about 5.83MPa at 70° and greater than that on the lingual side. The resulting displacement of the dentition revealed a tendency for the upper teeth to shift backward and the lower teeth to move forward by 0.46 to 0.49mm. The foregoing stress and displacement rose as the angle of the bite blocks increased.

CONCLUSIONS

CTBA with 70° bite blocks constituted an advantageous biomechanical setting for the treatment of mandibular retrognathia in teenagers and provided a superior therapeutic effect.

Malocclusion in cats associated with mandibular soft tissue trauma: a retrospective case-control study

OBJECTIVES

The aim of this study was to determine whether an association existed between cephalometric measurements, maxillomandibular dental arch distances and the occurrence of traumatic malocclusions in the mandibular soft tissues of cats.

METHODS

Cats that had presented for dental consultations and that underwent cone-beam CT during diagnostic assessment were included in the study and categorised as cases and controls in a 1:2 ratio. Cases were designated as cats with a clinical diagnosis of malocclusion causing trauma to the buccal mandibular soft tissues or pyogenic granuloma secondary to the trauma, and controls were designated as cats with the absence of such diagnoses and without a history of other musculoskeletal anomalies in the head. Cephalometric measurements, including skull and facial indexes, as well as distances and angulations between dental crowns and crown tips, were calculated and analysed statistically.

RESULTS

In total, 72 cats (24 cases and 48 controls) were included in the study. Cephalometric measurements revealed a significant association between the skull and facial indexes and the occurrence of traumatic malocclusions in the caudal teeth. Brachycephaly was a strong predictor of the occurrence of traumatic malocclusions. In addition, the space between crown tips and teeth angulations was a contributing factor to the trauma.

CONCLUSIONS AND RELEVANCE

Cats with traumatic malocclusions in the cheek teeth tend to present a narrower interdental space between the maxillary and mandibular carnassial teeth, mostly attributed to skeletal and dental malocclusion. These findings can be used to help raise awareness about this disease in cats and its association with brachycephaly. Cut-off values have been proposed and could be used in the selection of cats by breeders to reduce the occurrence of this disease.

Orthognathic Surgery and Relapse: A Systematic Review

BACKGROUND

This review aimed to analyze the relapse in orthognathic surgery.

METHODS

PubMed, Scopus, and Web of Science databases were used to find papers that matched our topic dating from 1 January 2012 up to November 2022. Inclusion criteria were (1) human studies, (2) open access studies, (3) studies concerning the correlation between orthognathic surgery and relapse. Exclusion criteria were: (1) in vitro or animal studies, (2) off-topic studies, (3) reviews, (4) other languages than English.

RESULTS

A total of 482 results were obtained resulting in 323 publications after duplicate removal (158). After screening and eligibility phases 247 records were excluded: 47 reviews, 5 in animals, 35 in vitro, 180 off-topic. The authors successfully retrieved the remaining 78 papers and evaluated their eligibility. A total of 14 studies from these were ultimately included in the review.

CONCLUSION

Using cephalometric examinations and digital study models, these studies reveal that the relapse after orthognathic surgery is an event that occurs in most of the cases. The limitation of our research is that most of the studies are retrospective and use small sample sizes. A future research goal should be to conduct long-term clinical trials with larger numbers of samples.

Significance of Non-Statistically Significant Results in the Prediction of Oral Health-Related Quality of Life in Orthodontic Patients: A Survey Using Two Linking Questionnaires

Patients with a fixed orthodontic appliance may have difficulties in maintaining good oral health-related quality of life (OHRQoL), and evaluating self-perceived OHRQoL in orthodontic patients could be challenging for their orthodontists. Therefore, this research was conducted to investigate whether orthodontic postgraduates would accurately evaluate the OHRQoL of their patients. Two self-administered questionnaires were designed for patients to rate their OHRQoL and for their orthodontic postgraduates to evaluate them on OHRQoL. All pairs of patients and their orthodontic postgraduates were requested to independently complete the questionnaires. Pearson's correlation and multiple linear regression were performed to determine the relationships of the variables and to identify significant predictors on OHRQoL, respectively. There were 132 pairs of orthodontic patients and their residents who completed the questionnaires. There were no significant correlations between OHRQoL perceived by patients and evaluated by their orthodontic postgraduates in all aspects of treatment needs and dietary difficulties (p > 0.05). In addition, the regression model demonstrated no significant predictors for the self-perceived treatment needs and dietary difficulties of orthodontic patients. There seemed to be challenges for orthodontic postgraduates to evaluate their patients' oral health-related quality of life. Therefore, the OHRQoL measures should be increasingly implemented in orthodontic education and practice in order to enhance the concept of patient-centered care.