MKA en de Juiste Maat

Rede, uitgesproken bij de aanvaarding van het ambt van hoogleraar in de Mondziekten, Kaak- en Aangezichtschirurgie en Bijzondere Tandheelkunde aan het Erasmus MC, faculteit van de Erasmus Universiteit Rotterda

Projection-wise Disentangling for Fair and Interpretable Representation Learning: Application to 3D Facial Shape Analysis

Confounding bias is a crucial problem when applying machine learning to practice, especially in clinical practice. We consider the problem of learning representations independent to multiple biases. In literature, this is mostly solved by purging the bias information from learned representations. We however expect this strategy to harm the diversity of information in the representation, and thus limiting its prospective usage (e.g., interpretation). Therefore, we propose to mitigate the bias while keeping almost all information in the latent representations, which enables us to observe and interpret them as well. To achieve this, we project latent features onto a learned vector direction, and enforce the independence between biases and projected features rather than all learned features. To interpret the mapping between projected features and input data, we propose projection-wise disentangling: a sampling and reconstruction along the learned vector direction. The proposed method was evaluated on the analysis of 3D facial shape and patient characteristics (N=5011). Experiments showed that this conceptually simple method achieved state-of-the-art fair prediction performance and interpretability, showing its great potential for clinical applications.Comment: Accepted at MICCAI 202

MESENCHYMAL STEM CELL-MEDIATED ENDOCHONDRAL OSSIFICATION UTILISING MICROPELLETS AND BRIEF CHONDROGENIC PRIMING

With limited autologous and donor bone graft availability, there is an increasing need for alternative graft substitutes. We have previously shown that chondrogenically priming mesenchymal stem cell (MSC) pellets for 28 d in vitro will reproducibly result in endochondral bone formation after in vivo implantation. However, pellet priming time for clinical applications is quite extensive. A micropellet (\xce\xbcpellet)-fibrin construct was developed and coupled, with a shorter priming period, determined by an in vitro time course experiment. In vitro data showed expression of chondrogenic genes and matrix production after 7 d of chondrogenic priming, indicating that briefer priming could possibly be used to induce bone formation in vivo. 7 and 28 d primed pellet, pellet-fibrin and \xce\xbcpellet-fibrin constructs were cultured for in vitro analysis and implanted subcutaneously for 8 weeks into nude mice. \xce\xbcpellet-fibrin constructs, cultured in vitro for 7 or 28 d, produced comparable bone to standard pellets in vivo. MSC-mediated bone formation was achieved following only 7 d of in vitro priming. Bone formation in vivo appeared to be influenced by overall matrix production pre-implantation. Given this short priming time and the injectable nature of the \xce\xbcpellet-fibrin constructs, this approach might be further developed as an injectable bone substitute, leading to a minimally-invasive treatment option, which would allow for tailored filling of bone defects

Effectiveness of the new mandatory mouthguard use and orodental injuries in Dutch field hockey

Objectives:Up to 68% of field hockey players have experienced at least one orodental injury in their sport career. Therefore, the Royal Dutch Hockey Association (KNHB) made mouthguard use mandatory for field hockey players during competition and training from August 2015 onwards. This study evaluates the effects of the new regulations on mouthguard use and the occurrence of injuries in Dutch field hockey. Methods:A 35-item online questionnaire about mouthguard use and orodental injuries was sent to 13 field hockey clubs in the Netherlands. Absolute numbers and percentages of mouthguard ownership, mouthguard use, number and type of injuries were assessed. The results were related to comparable data before mandatory mouthguard use. Associations of gender and training frequency with the number of injuries were analysed with logistic regression. Results:In total, 1169 hockey players were included in the study and almost all owned a mouthguard (females:99.6%, males:93.7%), which significantly increased after implementation (p &lt; 0.001). 90.6% of the respondents wore a mouthguard during matches and 70.1% during training. Of the 1169 players, 68(5.8%) experienced at least one orodental injury after the implementation with a total of 100 injuries. Injuries happened more often during matches (63.2%) than during training (36.8%). Lip cuts account for most of the injuries, the number of broken (p = 0.116) and knocked out teeth (p = 0.026) decreased. Conclusion:Although mouthguard use already increased in recent years, the new regulations led to an additional increase and a successful change of attitude towards mouthguard use. Most importantly, the severity of orodental injuries decreased measurable.</p

Effectiveness of the new mandatory mouthguard use and orodental injuries in Dutch field hockey

Objectives:Up to 68% of field hockey players have experienced at least one orodental injury in their sport career. Therefore, the Royal Dutch Hockey Association (KNHB) made mouthguard use mandatory for field hockey players during competition and training from August 2015 onwards. This study evaluates the effects of the new regulations on mouthguard use and the occurrence of injuries in Dutch field hockey. Methods:A 35-item online questionnaire about mouthguard use and orodental injuries was sent to 13 field hockey clubs in the Netherlands. Absolute numbers and percentages of mouthguard ownership, mouthguard use, number and type of injuries were assessed. The results were related to comparable data before mandatory mouthguard use. Associations of gender and training frequency with the number of injuries were analysed with logistic regression. Results:In total, 1169 hockey players were included in the study and almost all owned a mouthguard (females:99.6%, males:93.7%), which significantly increased after implementation (p &lt; 0.001). 90.6% of the respondents wore a mouthguard during matches and 70.1% during training. Of the 1169 players, 68(5.8%) experienced at least one orodental injury after the implementation with a total of 100 injuries. Injuries happened more often during matches (63.2%) than during training (36.8%). Lip cuts account for most of the injuries, the number of broken (p = 0.116) and knocked out teeth (p = 0.026) decreased. Conclusion:Although mouthguard use already increased in recent years, the new regulations led to an additional increase and a successful change of attitude towards mouthguard use. Most importantly, the severity of orodental injuries decreased measurable.</p

Adherence to dietary guidelines and dental caries among children:a longitudinal cohort study

BACKGROUND: Even though dietary sugars are the most important nutrient for caries development, the disease process is dependent on other dietary practices. The intake of individual nutrient components cannot be evaluated separately from the overall diet which includes other nutrients, foods and habits. Therefore, the aim of this study was to investigate the association between adherence to dietary guidelines and dental caries. METHODS: This study was embedded in the Generation R Study, conducted in Rotterdam, the Netherlands. In total, 2911 children were included in the present analyses. Dietary intake at the age of 8 years was assessed using food-frequency questionnaires. Diet quality scores were estimated, reflecting adherence to Dutch dietary guidelines. Dental caries was assessed at the age of 13 years using intra-oral photographs. Associations were estimated using multinomial logistic regression analyses, adjusted for sociodemographic characteristics and oral hygiene practices. RESULTS: The prevalence of dental caries at the age of 13 years was 33% (n = 969). Better diet quality was associated with a lower occurrence of severe dental caries after adjustments for sociodemographic factors [e.g. highest vs. lowest quartile of diet quality: odds ratio (OR) 0.62, 95% confidence interval (CI) 0.39-0.98]. After additional adjustments for oral hygiene practices, this association was not statistically significant (OR 0.65, 95% CI 0.41-1.03). CONCLUSION:Adherence to dietary guidelines has the potential to reduce dental caries in children; however, with proper oral hygiene practices, this relationship might be attenuated. To understand the role of dietary patterns and dental caries, the contributing role of daily eating occasions needs to be studied further.</p