Age-dependent effects on palate volume and morphology during orthodontic RME treatment

Predicting changes of incisor and facial profile following orthodontic treatment: a machine learning approach

BACKGROUND

Facial aesthetics is one of major motivations for seeking orthodontic treatment. However, even for experienced professionals, the impact and extent of incisor and soft tissue changes remain largely empirical. With the application of interdisciplinary approach, we aim to predict the changes of incisor and profile, while identifying significant predictors.

METHODS

A three-layer back-propagation artificial neural network model (BP-ANN) was constructed to predict incisor and profile changes of 346 patients, they were randomly divided into training, validation and testing cohort in the ratio of 7:1.5:1.5. The input data comprised of 28 predictors (model measurements, cephalometric analysis and other relevant information). Changes of U1-SN, LI-MP, Z angle and facial convex angle were set as continuous outcomes, mean square error (MSE), mean absolute error (MAE) and coefficient of determination (R²) were used as evaluation index. Change trends of Z angle and facial convex angle were set as categorical outcomes, accuracy, precision, recall, and F1 score were used as evaluation index. Furthermore, we utilized SHapley Additive exPlanations (SHAP) method to identify significant predictors in each model.

RESULTS

MSE/MAE/R2 values for U1-SN were 0.0042/0.055/0.84, U1-SN, MP-SN and ANB were identified as the top three influential predictors. MSE/MAE/R2 values for L1-MP were 0.0062/0.063/0.84, L1-MP, ANB and extraction pattern were identified as the top three influential predictors. MSE/MAE/R2 values for Z angle were 0.0027/0.043/0.80, Z angle, MP-SN and LL to E-plane were considered as the top three influential indicators. MSE/MAE/R2 values for facial convex angle were 0.0042/0.050/0.73, LL to E-plane, UL to E-plane and Z angle were considered as the top three influential indicators. Accuracy/precision/recall/F1 Score of the change trend of Z angle were 0.89/1.0/0.80/0.89, Z angle, Lip incompetence and LL to E-plane made the largest contributions. Accuracy/precision/recall/F1 Score of the change trend of facial convex angel were 0.93/0.87/0.93/0.86, key contributors were LL to E-plane, UL to E-plane and Z angle.

CONCLUSION

BP-ANN could be a promising method for objectively predicting incisor and profile changes prior to orthodontic treatment. Such model combined with key influential predictors could provide valuable reference for decision-making process and personalized aesthetic predictions.

Evaluation of the accuracy of a simplified hybrid method versus the traditional digital method for measuring palatal volume

Objective

This study aimed to compare a direct conventional 3D digital technique vis a vis a hybrid method in measuring palatal volume.

Materials and methods

Thirty maxillary casts were obtained from the records of patients undergoing orthodontic treatment and pre-conceived boundaries of the palatal vault were marked. Sample was categorised into Group I (Volume estimation using CBCT scan) and Group II (Volume estimation using hybrid method). Estimation of the palatal volume in this study involved filling the volume of interest in the palate with gypsum (Type IV) stone material and carefully carving according to the boundaries and anatomy. This positive reproduction of the palatal space was safely retrieved and then scanned in the NewTom GiANO HR Cone Beam Imaging setup. The obtained scan was analysed in NNT Software Version 3.10 and the volume of the palate was calculated. Two experienced orthodontists carried out the measurements to evaluate the inter and intra-observer reliability. This was compared with the palatal volume calculated by the conventional digital method using CBCT in the NNT Software.

Result

This study showed a consistent and narrow range of the confidence interval for palatal volume. Hence, the sample size was sufficient and had good precision. Considering a 95 % confidence interval, the intra-class correlation coefficient was robust (>0.9) for all measurements calculated by the hybrid method suggesting a high reliability. The mean difference in measurement of palatal volume (Group I vs, Group II) was 1.37 + 0.64 mm3 and the difference was statistically insignificant. Statistical t-test conducted between the two methods showed a p-value of 0.34, implying no statistically significant difference between the two methods.

Conclusion

The hybrid method for evaluating the palatal volume is simple, accurate and comparable to the conventional digital method. A major advantage of this simplified method is that the patient is not exposed to any radiation of CBCT. Also, need for a specific skillset for digitally measuring the palatal volume is not a must.

A Systematic Review of the Use of Intraoral Scanning for Human Identification Based on Palatal Morphology

A common application for intraoral scanners is the digitization of the morphology of teeth and palatal rugae. Palatal scans are most commonly required to fabricate complete dentures and immediate transitional dentures and serve as a reference point for assessing orthodontic results. However, they are also frequently included by accident, even though the main purpose of intraoral scanning is to reconstruct dentition using computer-aided manufacturing (CAM). The literature shows that the identification of disaster victims has frequently involved palatal rugae impressions. As the skull provides sound insulation, the rugae are resistant to heat, chemicals, and stress. Antemortem data might be difficult to find during a forensic inquiry, particularly in disaster victim identification cases. In contrast with DNA and fingerprints, there is a greater likelihood of having a dental record that contains palatal scans. With specialized software, the scans can be exported as open stereolithography (STL) files. Considering that a full case consumes up to about 100 MB of hard drive space, long-term storage should not be an issue compared to a plaster model. Additionally, dentists widely use online databases to exchange data for smile design, implant registration, and orthodontic purposes. This will produce a digital database that grows quickly and is readily usable for forensic investigations. The uniqueness of forensic features is frequently challenged; however, palatal morphology's unique trait could make it possible as it is characteristic of individuals as well as the most distinguishing factor. This review will highlight how rugae, palatal morphology, mirroring, superimposition, and geometrics can serve in forensic identification.

Evolution, current status, and future trends of maxillary skeletal expansion: a bibliometric analysis

OBJECTIVES

The study aims to conduct a bibliometric analysis on maxillary skeletal expansion to elucidate the evolution and current status and predict future research hotspots and trends.

MATERIAL AND METHODS

A search was conducted in the Web of Science Core Collection at the University of Hong Kong's electronic library using the query "(TS = maxillary expansion) AND (TS = skeletal expansion)." The resulting literature data were imported into CiteSpace 6.2.R4 and VOS viewer software to analyze authorship, countries, institutions, keywords, etc. RESULTS: A total of 923 articles were analyzed. The research in this field has shown a steady growth, with a significant increase since 2019. The USA and Italy have played prominent roles in contributing to the publication volume and strengthening collaborative exchanges. Clustering labels provide directions for in-depth analysis of the literature.

CONCLUSIONS

(1) MARPE (miniscrew-assisted rapid palatal expansion) and SARME (surgically assisted rapid maxillary expansion) have gained widespread attention and become research hotspots due to their applicability in adults whose growth and development have ceased, while still producing favorable skeletal effects. (2) In addition to widening the maxillary arch, maxillary expansion techniques have shown significant effects on increasing nasal cavity width and volume. However, there is still controversy regarding whether they can effectively improve the deviated nasal septum. (3) Maxillary skeletal expansion techniques have been shown to increase upper airway volume and improve breathing, making them potentially valuable in the treatment of obstructive sleep apnea (OSA).

CLINICAL RELEVANCE

This study can provide cutting-edge clinical recommendations for healthcare professionals to better formulate clinical strategies.

A novel method for assessment of human midpalatal sutures using CBCT-based geometric morphometrics and complexity scores

INTRODUCTION

Management of dentofacial deficiencies requires knowledge about sutural morphology and complexity. The present study assesses midpalatal sutural morphology based on human cone-beam computed tomography (CBCT) using geometric morphometrics (GMM) and complexity scores. The study is the first to apply a sutural complexity score to human CBCT datasets and demonstrates the potential such a score has to improve objectiveness and comparability when analysing the midpalatal suture.

MATERIALS AND METHODS

CBCTs of various age and sex groups were analysed retrospectively (n = 48). For the geometric morphometric analysis, landmark acquisition and generalised Procrustes superimposition were combined with principal component analysis to detect variability in sutural shape patterns. For complexity analysis, a windowed short-time Fourier transform with a power spectrum density (PSD) calculation was applied to resampled superimposed semi-landmarks.

RESULTS

According to the GMM, younger patients exhibited comparable sutural patterns. With increasing age, the shape variation increased among the samples. The principal components did not sufficiently capture complexity patterns, so an additional methodology was applied to assess characteristics such as sutural interdigitation. According to the complexity analysis, the average PSD complexity score was 1.465 (standard deviation = 0.010). Suture complexity increased with patient age (p < 0.0001), but was not influenced by sex (p = 0.588). The intra-class correlation coefficient exceeded 0.9, indicating intra-rater reliability.

CONCLUSION

Our study demonstrated that GMM applied to human CBCTs can reveal shape variations and allow the comparison of sutural morphologies across samples. We demonstrate that complexity scores can be applied to study human sutures captured in CBCTs and complement GMM for a comprehensive sutural analysis.