General and craniofacial development are complex adaptive processes influenced by diversity

Abstract

Complex systems are present in such diverse areas as social systems, economies, ecosystems and biology and, therefore, are highly relevant to dental research, education and practice. A Complex Adaptive System in biological development is a dynamic process in which, from interacting components at a lower level, higher level phenomena and structures emerge. Diversity makes substantial contributions to the performance of complex adaptive systems. It enhances the robustness of the process, allowing multiple responses to external stimuli as well as internal changes. From diversity comes variation in outcome and the possibility of major change; outliers in the distribution enhance the tipping points. The development of the dentition is a valuable, accessible model with extensive and reliable databases for investigating the role of complex adaptive systems in craniofacial and general development. The general characteristics of such systems are seen during tooth development: self-organization; bottom-up emergence; multitasking; self-adaptation; variation; tipping points; critical phases; and robustness. Dental findings are compatible with the Random Network Model, the Threshold Model and also with the Scale Free Network Model which has a Power Law distribution. In addition, dental development shows the characteristics of Modularity and Clustering to form Hierarchical Networks. The interactions between the genes (nodes) demonstrate Small World phenomena, Subgraph Motifs and Gene Regulatory Networks. Genetic mechanisms are involved in the creation and evolution of variation during development. The genetic factors interact with epigenetic and environmental factors at the molecular level and form complex networks within the cells. From these interactions emerge the higher level tissues, tooth germs and mineralized teeth. Approaching development in this way allows investigation of why there can be variations in phenotypes from identical genotypes; the phenotype is the outcome of perturbations in the cellular systems and networks, as well as of the genotype. Understanding and applying complexity theory will bring about substantial advances not only in dental research and education but also in the organization and delivery of oral health care.

Variations in dental arch morphology are outcomes of the complex adaptive system associated with the developmental variation of hypodontia

“…It forms part of the complex adaptive system (CAS) of oro-facial development whereby epithelial tissues and neural crest mesenchyme are involved in delicate signalling pathways with multiple molecular events that overlap each other [1][2][3][4]. For a system to be considered as complex and adaptive, it should exhibit the principles of self-organisation and self-adaptation.…”

“…Separate genetic pathways and genetic/epigenetic/environmental interactions occur simultaneously throughout the dental developmental process; this is evidence of multitasking. The intricate and multilevel processes that occur during odontogenesis demonstrate the characteristics of a CAS [1,[5][6][7][8].…”

Two complex adaptive systems in human development: Further studies of dental and fingerprint parameters

“…The human body is a complex adaptive system, and human development is a complex adaptive process [10]. This research has shown that both teeth and fingerprints are interconnected, yet they still have a degree of autonomy.…”

“…Human development is a complex adaptive process that is influenced by genetic, epigenetic and environmental factors [10]. Genes interact with epigenetic and environmental elements and create complex networks within cells, and from this process the higher level tissues are formed.…”

“…Primary teeth commence development around 4 to 6 weeks in utero [10], while ridged skin on the fingers starts to form around 10 to 16 weeks in utero [12]. Once the patterns have been stabilised, their unique and persistent morphology makes them valuable models in studying sexual dimorphism.…”