Comparative oral health status of two pre-Hispanic archaeological sites in Costa Rica

Dental and periodontal indicators provide key biocultural information for reconstructing diet, health, and cultural practices in ancient populations. This study compares oral health profiles from two pre-Hispanic Costa Rican sites located in distinct ecological settings: Palo Blanco (600-1,200 AD, Tempisque lowlands) and Rodríguez (800-1,550 AD, Central Highlands).

Macroscopic dental data were recorded for 11 individuals (seven from Palo Blanco site and four from Rodríguez site). Variables assessed included dental caries, calculus, antemortem tooth loss (AMTL), periodontal state (CEJ-AC), dental wear, periapical lesions, malocclusions, and intentional dental modifications. Statistical analyses included Fisher's exact tests for categorical comparisons, Wilcoxon rank-sum tests for periodontal measurements, Wilson 95% confidence intervals, and Bonferroni corrections for multiple testing. To evaluate whether AMTL followed a directional pattern across ecological settings, we applied a Cochran-Armitage Trend Test for ordered proportions, using highland, intermontane, and lowland contexts as ordinal categories. We also analyzed 136 isolated teeth from the studied populations.

Although overall caries prevalence did not differ between Palo Blanco and Rodríguez, the anatomical patterning of lesions revealed clear contrasts: buccolingual and root caries were concentrated in the lowland Palo Blanco population, whereas occlusal caries was more frequent in the highland Rodríguez sample. Heavier supragingival and subgingival calculus deposits were detected in Palo Blanco across all scoring systems. AMTL displayed the most pronounced disparity, occurring in 85.7% of Palo Blanco adults but in none from Rodríguez (p = 0.015). Periodontal disease followed the same trend, with significantly greater CEJ-AC distances at Palo Blanco. When viewed alongside the intermediate frequencies reported, the two populations form a coherent ecological gradient, from the comparatively healthy dentitions of the cool highlands to the more inflamed oral environments of the tropical dry lowlands.

Variation in periodontal disease, AMTL, and caries across the two sites reflect differing ecological conditions, food-processing practices, and dietary regimes. These results underscore the interpretive value of dental indicators for understanding biocultural adaptation in pre-Hispanic Costa Rica and provide a comparative baseline for future interdisciplinary studies incorporating isotopic, microwear, and biomolecular evidence.