Archaeological Index of Oro-Dental Disease
About this method
A holistic method for comparing oro-dental disease data from multiple diseases between individuals and groups
When assessing data on the impacts of tobacco consumption on dental disease, I quickly became frustrated with the large number of variables to contend with when comparing within and between different oro-dental diseases, and the issues with preservation that cause missing data and reduced our ability for accurate comparisons between individuals/groups.
After investigating the ways in which modern day dentists combine dental disease data to better understand oral health, I decided to produce a method where we could holistically combine different types of oro-dental diseases, whilst also accounting for differing preservation and unobservable teeth/alveolar bone.
This resulted in the production of the archaeological Index of Oro-Dental Disease (IOD) method. This formula calculates an 'oral health' index score for an individual, which weights different oro-dental diseases. Differences between archaeological groups can then be identified by comparing mean IOD values.
To test the method worked, I used a large modern-day oral health dataset and recoded it to have missing values, as we would expect in an archaeological dataset. When I applied the index method, the mean IOD scores from this dataset still demonstrated significant differences according to risk factors such as age, sex, and smoking status, demonstrating that the method worked at identifing differences between groups despite missing data.
I am now exploring how we can adjust application of the method, including comparison of age-matched samples and analysis of anterior and posterior teeth separately, to fine-tune this approach. I believe, with further work, this method could allow us to better understand the varied risk factors affecting oral health in the past.
Below, you can find calculators in which you can input dental disease data and produce an individual's IOD score. You can pick which calculator you would like to use based on whether you want to calculate a score using all teeth, or only anterior or posterior teeth.
If you have a large data set, click the button to download an excel spreadsheet that will produce IOD scores for multiple individuals at once.
Index of Oro-Dental Disease (IOD) Calculator
Davies-Barrett, A.M., Inskip, S.A., Holliday, R., Jakubovics, N. (2025).An ‘Index of Oro-dental Disease’: a holistic method for understanding the impacts of different risk factors on oral health in archaeological populations. International Journal of Paleopathology, 48, pp. 43-56
Categories
a = Caries
b = Periapical lesion
c = Antemortem tooth loss
d = Periodontal disease (grade 3 or more (Kerr, 1988))
L = Number of observed lesions in anterior sites per individual
S = Number of observable anterior sites per individual
W = Observability weighting
ΣW = the total sum of all observability weighting scores (Wa+Wb+Wc+Wd)
Weighting Scores*
Score 0: for any disease category if less than 8 observable sites are present.
Score 1: for caries, periapical lesion and periodontits if there are 8 or more sites observable
Score 2: for antemortem tooth loss if there are 8 or more sites observable.
*An observable site constitutes either a tooth (for caries), an alveolar socket (for antemortem tooth loss and periapical lesion), or an alveolar septum (for periodontal disease).
Formula
IOD Score =((La/Sa)Wa + (Lb/Sb)Wb + (Lc/Sc)Wc+ (Ld/Sd)Wd)/ΣW*100
Index of Oro-Dental Disease - Anterior Teeth Only (a-IOD) - Calculator
Davies-Barrett, A.M. and Inskip, S.A. (Forthcoming). Intersectional approaches to oral health: Investigating the impact of tobacco consumption in post-medieval England and Netherlands (c. AD 1500-1870).
Categories and formula are the same as for the IOD method, but the weighting scores differ. Only data for the incisors and canines are entered.
Weighting Scores*
Score 0: for any disease category if less than 4 observable sites are present.
Score 1: for caries, periapical lesion and periodontits if there are 4 or more sites observable
Score 2: for antemortem tooth loss if there are 4 or more sites observable.
*An observable site constitutes either a tooth (for caries), an alveolar socket (for antemortem tooth loss and periapical lesion), or an alveolar septum (for periodontal disease).
Index of Oro-Dental Disease - Posterior Teeth Only (p-IOD) - Calculator
Davies-Barrett, A.M. and Inskip, S.A. (Forthcoming). Intersectional approaches to oral health: Investigating the impact of tobacco consumption in post-medieval England and Netherlands (c. AD 1500-1870).
Categories and formula are the same as for the IOD method, but the weighting scores differ. Only data for the premolars and molars are entered.
Weighting Scores*
Score 0: for caries, antemortem tooth loss, and periapical lesion if less than 6 observable sites are present, and for periodontitis if less than 5 observable sites are present.
Score 1: for caries and periapical lesion, if there are 6 or more sites observable and for periodontitis, if there are 5 or more sites observable.
Score 2: for antemortem tooth loss if there are 6 or more sites observable.
*An observable site constitutes either a tooth (for caries), an alveolar socket (for antemortem tooth loss and periapical lesion), or an alveolar septum (for periodontal disease).
Relevant Publications
Davies-Barrett, A. M., Holliday, R., Jakubovics, N. S., & Inskip, S. A. (2025). An ‘Index of Oro-dental Disease’: A holistic method for understanding the impacts of different risk factors on oral health in archaeological populations. International Journal of Paleopathology, 48, 43–56. https://doi.org/10.1016/j.ijpp.2024.12.001
Awarded Volume 48 Highlight in the International Journal of Paleopathology for its potential impact on the field and other disciplines and its broader interest beyond academy.