Human Jaw Shrinkage - How to Save Your Child's Smile
Time to read 8 min
Time to read 8 min
In recent centuries, a significant and concerning trend has emerged in human populations - the shrinkage of our jaws. This unprecedented phenomenon is affecting the size and structure of our mandibles and maxillas, leading to a range of dental and health issues. This article aims to delve into the origins, causes, and potential solutions to our shrinking human jaw. Through a comprehensive analysis of scientific research and historical evidence, we can gain a deeper understanding of this phenomenon and its implications.
To comprehend the magnitude of our shifting jaw sizes, it is crucial to explore our evolutionary history. Anthropologists have long noticed striking differences between the jaw and dental structures of modern humans and our pre-agricultural ancestors from thousands of years ago. Comparisons between burial remains of hunter-gatherer societies and farming cultures have revealed distinct morphological disparities. The jaws and teeth of hunter-gatherers are generally larger, well-aligned, and provide ample space for all teeth, including wisdom teeth. In contrast, farming populations exhibit smaller jaws, dental malocclusions (misalignment of the upper and lower teeth), and a lack of space for wisdom teeth (1).
This transformation can be traced back to the Neolithic agricultural revolution, which occurred approximately 12,000 years ago. As humans transitioned from hunting and gathering to an agricultural lifestyle, their diets and overall way of life underwent significant changes. The introduction of highly processed and softer foods, like bread, cooked grains, and pasta, along with reduced chewing stress, played a pivotal role in the shrinking of our jaws. Our ancestors relied on tough and fibrous foods, which required substantial chewing to extract nutrition. These dietary changes, combined with sedentary lifestyles and cultural shifts, have resulted in human jaw shrinkage (2).
One of the reasons mouth breathing often goes unnoticed is its portrayal in popular media and advertising - we've normalized it. In advertising campaigns we often feature images of attractive individuals with their mouths slightly open, suggesting that this is an appealing and desirable way to present oneself. These subtle cues in media contribute to the normalization of mouth breathing, making it harder for people to recognize it as a potential issue for their oral and overall health.
Studies show that mouth breathing can contribute to conditions like obstructive sleep apnea because of the structural changes that occur in the jaw with long-term mouth breathing (4). Nasal breathing, on the other hand, offers numerous advantages, including proper humidification and filtration of incoming air, slower breathing rates, and improved overall health and longevity. We will cover mouth breathing in more detail in the next article.
Let's review a recent study whereby researchers investigated the relationship between tongue rest posture during sleep, facial features, and sleep habits. The study involved 27 participants, comprising 11 females and 16 males, who wore specialized mouth devices for three consecutive nights to monitor their tongue posture during sleep. Additionally, researchers collected data on facial structure using X-rays and plaster models.
The results yielded intriguing findings. They demonstrated a clear connection between changes in the Tongue Posture Index (TPI) during sleep and corresponding alterations in palatal height, the palatal height-to-width ratio, and lower face height. Furthermore, individuals who snored, breathed through their mouths, or preferred sleeping on their backs exhibited distinct variations in tongue posture during sleep (5).
In summary, this study highlights the intricate relationship between tongue posture during sleep, facial structure, and sleep habits. These insights provide valuable information about how lifestyle factors collectively contribute to the complex expression of craniofacial development, which can have lifelong consequences.
Genetics alone cannot explain the rapid shrinkage of human jaws observed over recent centuries. The timespan involved is too brief for substantial genetic alterations, and there's no apparent selection pressure favoring smaller jaws. Instead, the shifts in jaw size and shape predominantly stem from environmental factors like dietary preferences, cultural influences, and lifestyle habits. This phenomenon underscores the concept of "evolutionary mismatch," which emphasizes the mismatch between our contemporary environments and the natural developmental pathways that evolved over thousands of years (6).
Moreover, studies on non-human subjects have demonstrated that induced nasal blockages and dietary changes during critical periods of craniofacial growth can lead to morphological changes similar to what we observe in human populations. This further emphasizes the role of lifestyle and environmental factors in shaping our jaws and facial structures. It is essential to recognize that while genetics may contribute to certain traits, they do not condemn individuals to a life with specific conditions. By addressing the modifiable factors discussed earlier, we can potentially mitigate the impact of the shrinking human jaw (7).
Recognizing the issue of shrinking human jaws provides an important chance for proactive intervention and prevention. Parents, caregivers, dentists, and orthodontists can have a significant impact by encouraging healthy mouth, jawbone, and facial muscle development in children. Implementing straightforward yet effective measures today can potentially reduce the risk of future health problems and chronic conditions, ensuring that our children grow up with well-developed jaws and faces.
Encouraging children to chew sugar-free gum and gradually introducing less mushy foods during the transition to solid foods can aid in proper jaw development. Practices like myofunctional therapy and exercises that promote correct breathing and swallowing patterns can guide jaw growth in children from an early age.
Here are the basics of myofunctional therapy (we will go in-depth in another article):
These interventions focus on addressing the underlying causes rather than merely treating the symptoms. By emphasizing proper oral posture, breathing, and chewing habits, we can potentially mitigate the impact and reverse the trend of shrinking human jaws (7).
The consequences of shrinking human jaws extend beyond dental and facial aesthetics. Conditions such as obstructive sleep apnea, constricted airways, and decreased respiratory fitness are prevalent among individuals with smaller jaws (4). Sleep deprivation resulting from sleep apnea can lead to increased stress levels, which are associated with a higher risk of various health issues, including heart disease, high blood pressure, depression, cancer, and Alzheimer's disease. By addressing jaw health, we have the potential to improve overall well-being, enhance sleep quality, and reduce the burden of associated health conditions.
Awareness and understanding of the shrinking human jaw are pivotal in driving positive change. Continued research and education on this topic are essential to help healthcare professionals and individuals alike appreciate the significance of taking proactive steps to promote proper jaw development. This knowledge can be seamlessly integrated into clinical practices and public health initiatives. Collaboration among parents, caregivers, dentists, orthodontists, and researchers is crucial for implementing evidence-based interventions and preventive measures.
The evidence highlighting jaw shrinkage should serve as a clarion call, urging us to reevaluate our lifestyle choices, dietary habits, and breathing patterns. Through collective efforts and a shift towards advocating for proper craniofacial development, we have the potential to reverse the trend of shrinking jaws, ultimately enhancing the overall health and well-being of future generations.
Shrinking human jaws represent a significant yet often overlooked public health issue. It is not primarily a genetic matter but rather a consequence of modern practices and lifestyle choices. The repercussions of jaw shrinkage extend beyond dental concerns, impacting overall health and quality of life. However, by actively promoting proper jaw development through early interventions, especially in children, by encouraging healthy breathing, chewing, and eating habits, we can alleviate the effects of shrinking jaws and prevent future health challenges.
Education and awareness play pivotal roles in empowering individuals and healthcare professionals to take action, ensuring optimal jaw development for generations to come. Let us join forces to raise awareness and embark on this journey together, championing proper jaw development and enhancing the overall health and well-being of humanity.
Latham, K. J. (2013). Human Health and the Neolithic Revolution: An Overview of Impacts of the Agricultural Transition on Oral Health, Epidemiology, and the Human Body. Nebraska Anthropologist, Department of Anthropology, University of Nebraska-Lincoln.
Pinhasi, R., Eshed, V., & von Cramon-Taubadel, N. (2015). Incongruity between Affinity Patterns Based on Mandibular and Lower Dental Dimensions following the Transition to Agriculture in the Near East, Anatolia and Europe. PLoS ONE, 10(2), e0117301. https://doi.org/10.1371/journal.pone.0117301
Lin, L., Zhao, T., Qin, D., Hua, F., & He, H. (2022). The impact of mouth breathing on dentofacial development: A concise review. Frontiers in Public Health, 10, 929165. https://doi.org/10.3389/fpubh.2022.929165
Victor, L. D. (1999). Obstructive Sleep Apnea. American Family Physician, 60(8), 2279-2286. https://www.aafp.org/pubs/afp/issues/1999/1115/p2279.html
Tingey, B. J. (2011). Sleeping Tongue Posture and Its Relationship to Craniofacial Morphology (Master's thesis). Loma Linda University. https://scholarsrepository.llu.edu/etd/66
Manus, M. B. (2018). Evolutionary mismatch. Evolutionary Medicine and Public Health, 2018(1), 190–191. https://doi.org/10.1093/emph/eoy023