Teeth are highly informative in the study of past human populations. In particular, the occurrence of lesions in the masticatory apparatus relates diseases, diet, and living conditions. The dental pathology of three skeletal samples from the north-central part of Latium (central Italy) is reported. Two of them belong to the Roman Imperial Age (1st–3rd century AD): the first (including 942 permanent teeth and 1,085 tooth sockets) represents the rural town of Lucus Feroniae and is mainly composed of slaves and/or war veterans, whereas the second (872 permanent teeth and 1,325 tooth sockets) comes from the Isola Sacra necropolis at Portus Romae and represents the “middle class” segment of an urban population. The medieval sample (912 teeth and 1,097 tooth sockets), dated to the 7th century AD, belongs to the Lombard necropolis of La Selvicciola. All of the samples were examined for caries, abscesses, antemortem tooth loss, calculus, alveolar resorption, attrition, and enamel hypoplasia; standard methods were used to identify, classify, and quantify these conditions. The results reveal different patterns of dental and alveolar lesions for the three populations, indicating a different combination of dietary factors and hygienic conditions in the Roman samples compared to the Lombard series. As evidenced by multivariate correspondece analysis, the Romans show afffinites between each other, whereas the Medieval sample appears associated with the incidence of caries and the pathological conditions related to them, thus indicating increase of these lesions and deterioration of the quality of life in the transition to the early Middle Ages. These data agree with the respective archeological characterizations of the necropolises and the hypothetical social composition of each population. Am. J. Hum. Biol. 11:327–341. © 1999 Wiley-Liss, Inc.