Coronal and apical lesions, environmental factors: study in a modern and an archeological population.

Apical periodontitis (AP) are frequent findings in contemporary dental practice in association with dental pathology or dental care. They have also been studied from an anthropological background. The purpose of this study was to compare the prevalence of apical and dental lesions in an archeological Middle Ages sample and a modern population, and to evaluate the influence of environmental factors. Both the archaeological sample group and dental practice subjects were from southern France. The study included full mouth surveys of 252 individuals (2,780 teeth) from a historic necropolis and 223 subjects (5,678 teeth) randomly selected from the Gard area. Tooth wear, caries, and AP were accounted for clinically and radiographically according to specific indexes. Significant differences were found between period and age in the archeological sample as regards the main risk factors for AP. Antemortem teeth loss and dental wear had been reduced, whereas caries rates and AP had increased between archaeological and modern population. The AP ratio was associated with the level of dental care in the modern population. Although significant variations could be observed between archaeological periods, the rupture in E3 (sixteenth and seventeenth centuries) leads to consider the associated population as a premodern. However, it was found that although cultural and alimentary factors seemed to be the main risk factors in an archeological population, dental care seemed to have a strong influence on AP ratio in modern ones.

A comparative analysis of periapical health based on historic and current data.

AIM: To compare periapical health using samples from prehistoric and historic periods until the present day, and to emphasize the major risk indicators for apical periodontitis (AP). METHODOLOGY: A comparative survey to assess periapical health was performed on five samples (525 individuals) drawn from different periods of history within the time frame 2000 BC to 2000 AD. Twenty-one binary risk indicators for AP were retained for a logistic regression model. The probability of a diseased tooth was defined from a two-level response variable based on the periapical index (PAI). An individual regression model was computed with partial least squares (PLS) regression model, based on the individual mean values of the nine retained risk indicators. RESULTS: Condensing osteitis, tooth wear, caries, root fillings and the presence of inadequate root fillings were associated with the PAI levels. The maxillary molars and recent time periods (contemporaneous and seventeenth century) were also risk indicators for the pathological condition. The PLS regression for individuals demonstrated correlations between risk factors. This multidimensional analysis indicated that the mean PAI was correlated mainly with caries and condensing osteitis. Condensing osteitis was more frequent in the mandibular than in the maxillary bone (P=0.001), and correlated with tooth wear in ancient periods. CONCLUSIONS: This comparative analysis demonstrated a significantly higher prevalence of AP in the contemporary period. The most important risk indicators for that period were the presence of inadequate root fillings, carious lesions and condensing osteitis.

Effect of masticatory cycles on apical leakage of obturated teeth.

This study investigated the effect of apical leakage due to masticatory cycles on root canal treatment. Twenty upper maxillary molars were first obturated using the warm vertical compaction technique. Four maxillary casts were then built, with each holding four of the sample molars. The molars were embedded in resin with the roots separated from the resin by means of a light silicon. The four remaining teeth served as controls and were not submitted to occlusal forces. A mechanical device to simulate masticatory cycles subjected the teeth to 0.5 x 10(6) cycles (group A), 10(6) cycles (group B), 2 x 10(6) cycles (group C), and 3 x 10(6) cycles (group D); the control was group E. The roots were placed in 2% methylene blue dye solution for 72 h and then sectioned longitudinally so that dye penetration could be measured. The mean values of dye penetration were: 3.70 +/- 0.69 mm, group A; 5.00 +/- 1.14 mm, group B; 6.00 +/- 1.01 mm, group C; 7.23 +/- 0.66 mm, group D; and 2.74 +/- 0.75 mm, group E. The value of dye penetration increased in correlation with the number of masticatory cycles. This in vitro study suggests the significant effect of masticatory loads on apical leakage.