Sexual dimorphism and dentistry
Featured Products Promotional FeaturesPosted by: Dental Design 15th November 2021
Sex is one of the most basic differentiating factors between patients, and has been shown to affect health outcomes and disease in myriad ways. Despite this, a great deal of medical research has not adequately accounted for even this basic distinction between patients, treating women as essentially interchangeable with men. Women experience adverse drug reactions nearly twice as often as men, and a major component of this is likely to be caused by historical and contemporary failures in adequately enrolling women in clinical trials, or even considering sex in analysis.[1]
Physiological differences between the sexes can affect immune system function and disease susceptibility. Gender roles and expectations can also markedly affect behaviour and psychological wellbeing, which in turn can have health consequences. For example, smoking prevalence is notably higher among men (in the UK, 15.9% of men smoke versus 12.5% of women). Other sociological factors can intertwine or exist independently alongside gender. To use the smoking example again, among the British population cultural/ethnic background plays a modifying role, with, for instance, comparatively few Asian women taking up smoking on average (2.9% women, 13.9% men).[2] Socio-economic class is a major modifier of many aspects of life, not least health outcomes and morbidity, and gender has a very complex relationship with socio-economic status.
Policy oversights relating to sex have also put men’s health at risk. For example, the human papillomavirus (HPV) vaccine was historically only given to girls. The reasoning being that because heteronormativity was assumed, men would be indirectly protected, allowing for a cheaper, less comprehensive vaccination programme. It is now known that some strains of HPV are strongly linked to a range of cancers that men are susceptible to, including anal cancer, cancer of the penis and cancers of the head and neck. The NHS now also vaccinates boys born after September 1st 2006, during secondary education (those who missed vaccination during school can access it through the NHS until their 25th birthday). However, this has still left several generations of men at increased risk of eventually developing potentially fatal and life-changing cancers. Many patients may benefit from being informed that men who have sex with men (MSM) and trans women (women assigned male at birth), up to and including 45 years old, are now able to receive HPV vaccination on the NHS. This service is freely offered at sexual health and HIV clinics in England.[3]
Statistically, women are at greater risk of developing caries, and this appears to occur from puberty (12 years old and onwards). The discrepancy is not found during the primary dentition stages, indicating that there is some factor or factors that come into play during this time, but it is contentious within the literature as to what these are. Behavioural explanations are often forwarded, however, female participants appear to consume less sweets and soft drinks, while also brushing their teeth more frequently than male counterparts.[4] Given that sugar exposure and oral hygiene are classically regarded as the key factors in caries development, this would suggest that something else is occurring.
Contrastingly, men appear to be at greater risk of developing periodontitis (approximately 57% men compared to 37% women), with the disparity highest in cases of severe periodontitis. Unfortunately, key classical studies of periodontal disease were conducted with exclusively male samples, which raises questions on how much their results can be generalised. As periodontitis is driven by a complex interaction between infectious microbial activity and host immune response, it is possible, even likely, that sexual dimorphism in immune response plays a role in relative risk. Differences in microbiota between sexes may also be a factor.[5]
On the macro level, some structural differences are readily apparent, with the mandible, for example, usually exhibiting significant dimorphism between sexes. A CBCT study has found that women typically have a notably thicker Schneiderian membrane, perforation of which is a relatively common complication in certain implant and bone augmentation procedures.[6] Some differences extend down to the microscopic level, with recent research demonstrating that sexual dimorphism appears to affect cellular responses in ways that could impact the success of numerous treatments including dental implants. While osteointegration can broadly be reliably achieved, cells from male and female patients react differently in response to various hormones and growth factors.[7] Further study in this area may improve osteointegration outcomes.
It is critical that we move away from inaccurate universalist models, that treat patients as fundamentally interchangeable, and towards more tailored treatments. If you would like to gain more insight into patient-centric diagnosis and treatment, Ucer Education is at the forefront of postgraduate education in implantology in the UK. Led by Specialist Oral Surgeon, Professor Cemal Ucer, Ucer Education has taught thousands of satisfied dentists in the art of implantology, covering everything from treatment planning to post-operative care, as well as many other facets of dentistry.
We have a long way to go to redress historical research biases, but we can already see some of the diagnostic and treatment benefits to accomplishing this. The moral basis is self-evident, but doing so also brings a tangibly more accurate and actionable picture of dental realities into focus.
For more information please contact Professor Ucer at ucer@icedental.institute or Mel Hay at mel@mdic.co
01612 371842
www.ucer-clinic.dental
[1] Zucker I., Prendergast B. Sex differences in pharmacokinetics predict adverse drug reactions in women. Biology of Sex Differences.2020; 11:32. https://doi.org/10.1186/s13293-020-00308-5 September 2, 2021.
[2] ONS. Adult smoking habits in the UK: 2019. Office for National Statistics. 2020. https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/healthandlifeexpectancies/bulletins/adultsmokinghabitsingreatbritain/2019 September 2, 2021.
[3] NHS. HPV vaccine overview. NHS. 2019. https://www.nhs.uk/conditions/vaccinations/hpv-human-papillomavirus-vaccine/ September 2, 2021.
[4] Papadaki S., Douglas G., HaniBani A., Kang J. Gender differences in caries and periodontal status in UK children. medRxiv. 2021. https://doi.org/10.1101/2021.03.24.2125384 September 2, 2021.
[5] Ioannidou E. The sex and gender intersection in chronic periodontitis. Frontiers in Public Health. 2017; 5: 189. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543279/ September 6, 2021.
[6] Takalkar S., Girotra C., Kini Y., Padhye M., Tomar G., Acharya S., Gite M. Evaluation of sexual dimorphism in Schneider membrane thickness using cone-beam computed tomography (CBCT) for its clinical and forensic implications. Journal of Maxillofacial and Oral Surgery. 2021. https://doi.org/10.1007/s12663-021-01531-2 September 6, 2021.
[7] Berger M., Cohen D., Olivares-Navarrete R., Williams J., Cochran D., Boyan B., Schwartz Z. Human osteoblasts exhibit sexual dimorphism in their response to estrogen on microstructured titanium surfaces. Biology of Sex Differences. 2018; 9: 30. https://bsd.biomedcentral.com/articles/10.1186/s13293-018-0190-x September 6, 2021.
