Applying artificial intelligence to assess the impact of orthognathic treatment on facial attractiveness and estimated age

This observational study aimed to use artificial intelligence to describe the impact of orthognathic treatment on facial attractiveness and age appearance. Pre- and post-treatment photographs (n=2164) of 146 consecutive orthognathic patients were collected for this longitudinal retrospective single-centre study. Every image was annotated with patient-related data (age; sex; malocclusion; performed surgery). For every image, facial attractiveness (score: 0-100) and apparent age were established with dedicated convolutional neural networks trained on >0.5million images for age estimation and with >17million ratings for attractiveness. Results for pre- and post-treatment photographs were averaged for every patient separately, and apparent age compared to real age (appearance). Changes in appearance and facial attractiveness were statistically examined. Analyses were performed on the entire sample and subgroups (sex; malocclusion; performed surgery). According to the algorithms, most patients' appearance improved with treatment (66.4%), resulting in younger appearance of nearly 1year [mean change: -0.93years (95% confidence interval (CI): -1.50; -0.36); p=0.002), especially after profile-altering surgery. Orthognathic treatment had similarly a beneficial effect on attractiveness in 74.7% [mean difference: 1.22 (95% CI: 0.81; 1.63); p<0.001], especially after lower jaw surgery. This investigation illustrates that artificial intelligence might be considered to score facial attractiveness and apparent age in orthognathic patients

Factors influencing fixed retention practices in German-speaking Switzerland: A survey

Aim: Several surveys evaluate different retention approaches among orthodontists, but none exist for general dentists. The primary aim of this survey was to record the preferred fixed retainer designs and retention protocols amongst general dentists and orthodontists in Switzerland. A secondary aim was to investigate whether retention patterns were associated with parameters such as gender, university of graduation, time in practice, and specialist status. Methods: An anonymized questionnaire was distributed to general dentists (n = 401) and orthodontists (n = 398) practicing in the German-speaking part of Switzerland. A total of 768 questionnaires could be delivered, 562 (73.2 %) were returned and evaluated. Descriptive statistics were performed and responses to questions of interest were converted to binary outcomes and analyzed using multiple logistic regression. Any associations between the answers and gender, university of graduation (Swiss or foreign), years in practice, and specialist status (orthodontist/general dentist) were assessed. Results: Almost all responding orthodontists (98.0 %) and nearly a third of general dentists (29.6 %) reported bonding fixed retainers regularly. The answers were not associated with the practitioner's gender. The university of graduation and number of years in practice had a moderate impact on the responses. The answers were mostly influenced by specialist status. Conclusion: Graduation school, years in practice, and specialist status influence retention protocol, and evidence-based guidelines for fixed retention should be issued to minimize these effects. Based on the observation that bonding and maintenance of retainers are also performed by general dentists, these guidelines should be taught in dental school and not during post-graduate training

Craniofacial growth and SITAR growth curve analysis

BACKGROUND: SITAR (SuperImposition by Translation And Rotation) is a shape invariant growth curve model that effectively summarizes somatic growth in puberty. AIM: To apply the SITAR model to longitudinal mandibular growth data to clarify its suitability to facial growth analysis. SUBJECTS AND METHODS: 2D-cephalometric data on two mandibular measurements (AP: articulare–pogonion; CP: condylion–pogonion) were selected from the Denver Growth Study, consisting of longitudinal records (age range: 7.9–19.0 years) of females (sample size N: 21; number of radiographs n: 154) and males (N: 18; n: 137). The SITAR mixed effects model estimated, for each measurement and gender separately, a mean growth curve versus chronological age, along with mean age at peak velocity (APV) and peak velocity (PV), plus subject-specific random effects for PV and mean size. The models were also fitted versus Greulich–Pyle bone age. RESULTS: In males, mean APV occurred at 14.6 years (AP) and 14.4 years (CP), with mean PV 3.1 mm/year (AP) and 3.3 mm/year (CP). In females, APV occurred at 11.6 years (AP and CP), with mean PV 2.3 mm/year (AP) and 2.4 mm/year (CP). The models explained 95–96 per cent of the cross-sectional variance for males and 92–93 per cent for females. The random effects demonstrated standard deviations (SDs) in size of 5.6 mm for males and 3.9 mm for females, and SDs for PV between 0.3 and 0.5 mm/year. The bone age results were similar. CONCLUSION: The SITAR model is a useful tool to analyse epidemiological craniofacial growth based on cephalometric data and provides an array of information on pubertal mandibular growth and its variance in a concise manner

Surfing the spectrum - what is on the horizon?

Diagnostic imaging techniques have evolved with technological advancements - but how far? The objective of this article was to explore the electromagnetic spectrum to find imaging techniques which may deliver diagnostic information of equal, or improved, standing to conventional radiographs and to explore any developments within radiography which may yield improved diagnostic data. A comprehensive literature search was performed using Medline, Web of Knowledge, Science Direct and PubMed Databases. Boolean Operators were used and key-terms included (not exclusively): terahertz, X-ray, ultraviolet, visible, infra-red, magnetic resonance, dental, diagnostic, caries and periodontal. Radiographic techniques are primarily used for diagnostic imaging in dentistry, and continued developments in X-ray imaging include: phase contrast, darkfield and spectral imaging. Other modalities have potential application, for example, terahertz, laser doppler and optical techniques, but require further development. In particular, infra-red imaging has regenerated interest with caries detection in vitro, due to improved quality and accessibility of cameras. Non-ionising imaging techniques, for example, infra-red, are becoming more commensurate with traditional radiographic techniques for caries detection. Nevertheless, X-rays continue to be the leading diagnostic image for dentists, with improved diagnostic potential for lower radiation dose becoming a reality

Langzeitbetreuung nach kieferorthopädischer Behandlung. Wie viel Retention braucht die Unterkieferfront?

Um den dauerhaften Erfolg einer kieferorthopädischen Behandlung beim Jugendlichen zu gewährleisten, werden häufig Retainer in der Unterkieferfront geklebt. Die Wahl des Retainer-Designs ist eine Gratwanderung zwischen dem Wunsch nach maximaler Stabilität und der Sorge vor möglichen Nebenwirkungen und Komplikationen. Bezüglich der Retentionsdauer gilt es, die Gefahr des Rezidivs den eventuellen Folgen einer jahrelangen Retention gegenüberzustellen

Idealer Extraktionszeitpunkt bei ersten bleibenden Molaren. Eine Literaturübersicht

In Fällen von Hypomineralisation mit extensivem Schmelzverlust kann die Extraktion der befallenen ersten Molaren eine adäquate Therapiemöglichkeit darstellen. Aus kieferorthopädischer Sicht gibt es aber keine klare Meinung über den günstigsten Extraktionszeitpunkt. Anhand einer systematischen Literaturübersicht über die Extraktion von 6-Jahr-Molaren, bei welcher der größte mögliche spontane Lückenschluss zu erwarten ist, wurde versucht, den idealen Extraktionszeitpunkt zu eruieren. Basierend auf einer elektronischen Suche, die durch eine manuelle Recherche ergänzt wurde, konnten aus anfänglich 190 Studien lediglich vier Publikationen zur genaueren Analyse herangezogen werden. Da für den Oberkiefer nur wenige Daten zur Verfügung standen, lieferte die Metaanalyse keine eindeutigen Resultate. Mit Extraktionen, die vor einem Lebensalter von 10,5 Jahren durchgeführt wurden, ließ sich jedoch ein tendenziell besseres klinisches Ergebnis erzielen. Im Unterkiefer hingegen führten Extraktionen von befallenen Zähnen im Alter zwischen 8 und 11,5 Jahren zu signifikant besseren Resultaten. In jedem Fall empfiehlt sich aber eine kieferorthopädische Betreuung, da Restlücken auch bei einem idealen Extraktionszeitpunkt nicht auszuschließen sin

Nutzen-Risiko-Abwägung: Darf ich bei einer Schwangeren Röntgenbilder anfertigen?

Gelegentlich wird der Zahnarzt mit der Frage konfrontiert, ob er eine Schwangere röntgen darf oder nicht. Eine einfache und pauschale Antwort gibt es nicht. Es soll aber hier der Versuch unternommen werden, gewisse Klarheit über die Schädigungswahrscheinlichkeit zu verschaffen, damit der Zahnarzt eine einzelfallbezogene evidenzbasierte Entscheidung treffen kann

Does the decision to extract influence the development of gingival recessions?: A retrospective long-term evaluation

Objectives: Mandibular anterior crowding can be treated by expanding the dental arch or by extracting teeth, usually premolars. The aim of this study was to assess long-term outcomes of extraction versus non-extraction therapies in terms of gingival recession. Methods: Fifty consecutive patients were selected, including 26non-extraction and 24extraction cases. All had been treated with fixed appliances because of well-defined comparable moderate crowding and Angle ClassI malocclusion. Patient age was documented before treatment, upon debonding, and during retention, thus, allowing the calculation of the duration of active treatment and retention. The records available for these three points in time included casts and cephalograms. The casts were used to quantify mandibular anterior crowding and the associated clinical crown lengths. Based on the cephalograms, a number of symphyseal variables were measured. Data analysis included descriptive statistics, correlation tests, and multiple regressions. Results: For accurate comparison of the extraction and non-extraction treatment groups, we required and verified that no significant intergroup differences were present with regard to initial crowding, duration of retention, and age at final record-taking. Both groups revealed increases in crown length, which fell short of statistical significance but were twice as large for canines than for incisors. The treatment decisions to extract premolars did result in significantly different topographic positions of the lower incisors, but they made no difference in the recession outcomes. None of the variables in our regression analysis was found to predict gingival recession. Conclusion: Findings of gingival recession in patients having undergone orthodontic treatment do not seem to be related to extraction/non-extraction treatment decisions