|Durham Anthropology Journal
Volume 12(2-3) Copyright © 2005, Ryta Łagocka, Katarzyna Jakubowska, Mariusz Lipski, Krzysztof Woźniak, Jadwiga Buczkowska-Radlińska, Dariusz Chlubek
Summary: The analysis of aspects of archaeological teeth provides complementary data that contribute to our understanding of health and disease in past human populations. The aim of the study was to examine the aspects of permanent maxillary first molars from skulls found in three archaeological burial sites in western Poland. One hundred and seventy nine human permanent maxillary first molars were collected (83 female, 96 male). The teeth were obtained from skulls found in three archeological sites in Poland: Sypniewo, Milicz and Wrocław. The skeletons dated from XII-XIV century. The following features were evaluated: mesiodistal and buccolingual dimensions of the crown, cusp pattern, the degree of dental wear, number and shapes of the roots, number of apical foramina per root and their position, length of the roots. This study has shown that the basic dimensions of teeth have not changed during the last 700-900 years in people of Caucasian origin residing in the territory of present-day western Poland. Considerable dental wear and lack of caries in the teeth examined suggest that they consumed food material that contained particles of abrasives with low concentration of carbohydrates. Despite the complicated root and canal anatomy of the molars, the prevalence of four or more apical foramina in archeological maxillary first molars and the presence of a high percentage of fused roots suggest that morphology and anatomy of these teeth was as complicated in the XII -XIV centuries as present teeth are.
1.1. In the last two decades of the twentieth century new technology and new methods of endodontic treatment have been developed. This has caused the growth in interest in tooth root and canal anatomy. Because of the complexity of molar and premolars roots and canal systems, these teeth are investigated especially. It appears that aberrations, such as C-shaped canals, additional canals or fused roots, are not only found in the teeth of modern man. Root canals and C-shaped roots were first documented in 1908 and 1911, after examination of the skeletal remains of members of the Neanderthal race (q. acc. Manning 1990b).
1.2. Dental caries, disturbances in dental development, dental trauma, dental abrasion, dental discoloration and other dental diseases, which are widespread in the modern world, have also occurred in past human populations (Alexandersen et al. 1998). The analysis of both skeletal and dental disease provides complementary data that contribute to our understanding of health and disease in past human populations. Despite a substantial literature on paleopathology, a full understanding of dental paleopathology and its implications awaits further research. However, comparisons of various manifestations of dental disease between different human groups with varying economies, for example, has revealed important relationships between diet and dental caries, as well as biological stress and developmental defects in teeth, such as enamel hypoplasia (Ortner 2002).
2.1. One hundred and seventy nine human permanent maxillary first molars were collected (83 female, 96 male). The teeth were obtained from skulls found in three archeological sites in Poland: Sypniewo, Milicz and Wrocław. The skeletons dated from XII-XIV century. Each examined tooth was carefully dissected from the upper jaw. The teeth demonstrated fully formed roots. All of the teeth were identified absolutely, at the time of extraction, as maxillary first molars.
2.2. The following features were evaluated: mesiodistal and buccolingual dimensions of the crown, cusp pattern, the degree of dental wear, number and shape of the roots, length of the roots. The mesiodistal and buccolingual dimensions of the crowns were measured in the greatest circumference of each tooth crown. The length of the roots was measured from the cervical region of each tooth to the root apex in straight line. To categorize the degree of dental wear, the Tooth Wear Index by Martin was used (Knychalska-Karwan 1995), which describes six scores:
2.3. The roots were examined with a magnifying glass and data was collected according to the following categories: number of apical foramina per root and their position. Radiographs were taken from each tooth.
2.4. The data obtained were analyzed by calculating mean, standard deviation and median. To investigate any relationships between the variable,s Chi-squared and U Mann Whitney's tests were used. The level of significance was chosen at p ≤ 0.05.
3.1. The results presented in Table 1 show that mesiodistal and buccolingual dimensions of the male crowns are slightly higher than female ones, with statistically significant (p ≤ 0.04) differences in buccolingual dimension. There is no statistically significant difference in cusp pattern between sexes (Table 2). It was noteworthy that only 2.79% of the first maxillary crowns have a Carabelli cusp.
3.2. The majority of the examined teeth exhibit considerable dental wear. The number and percentage of the first maxillary molars with different values of the Tooth Wear Index is presented in Table 3. The occlusal surface of 40.8% of examined molars had been abraded to a flat surface. Probing with a dental explorer reveals in eight cases (4.5%) that the wear is so severe that the pulp chamber is exposed. Tooth wear is significantly more frequently in males than in females (p ≤ 0.02). Flat attrition facets were also sometimes found.
3.4. The results presented in Table 4 show that of the 179 maxillary first molars studied, 159 (88.8%) teeth have three separate roots, 20 (11.2%) teeth have fused two roots: distobuccal or mesiobuccal with palatal root. There are no statistically significant differences between number of fused distobuccal and palatal roots between sexes. The presence of fused mesiobuccal and palatal roots is significantly more frequently in females (p ≤ 0.03). Female tooth roots are significantly shorter than those of males: mesiobuccal root p ≤ 0.002; distobuccal root p ≤ 0.007 and palatal root p ≤ 0.008 (Table 5).
3.5. Table 6 presents the number and percentage of the archeological first maxillary molar roots with one, two, three or four apical foramina. There were no statistically significant differences between sexes in the number of the apical foramina in distobuccal, palatal or fused roots. Over fifty one percent of the maxillary first molars have two or more apical foramina in the apex of the mesiobuccal root. Differences between number of apical foramina in mesiobuccal root between sexes were on the limit of significance (p ≤ 0.05). The apical foramina are positioned at the apex in 33 out of the 159 palatal roots, 38 out of the 159 distobuccal roots, 40 out of the 156 mesiobuccal roots, seven out of the 18 distobuccal and palatal root fused and two out of the two mesiobuccal and palatal root fused. Of the 330 roots examined, 120 (36.4%) show the apical foramen to be at the apex (Manning 1990a).
4.1. The mesiodistal and buccolingual dimensions of the first maxillary molars of Caucasian origin amount to 10.1 and 11.7 mm respectively (Lehmann and Hellwig 1994); a well developed Carabelli cusp appears in 10-15%. Frequently a furrow appears, instead of cusp, which has various depths and which separates the residual cusp from the mesiopalatal cusp. Such furrows are found in 44% of the molars (Łasiński 1985). In this study, Carabelli cusps are found only in 5 % of the examined teeth crowns of the first maxillary molars, and the furrow was found in 20.7 % of the teeth. The archeological first maxillary molars examined show considerably wear, so a Carabelli cusp in the same cases could easily be abraded and thus not noticed. In the available literature, the length of the tooth roots are given together with the length of the crowns (Lehmann and Hellwig 1994). In this study, this was impossible, because of severe wear in the majority of the tooth crowns.
4.2. Dental abrasion is a well-known phenomenon in archeological skeletons. The severity of abrasion is much greater in archeological skeletons than in most modern skeletons. Mehta and Evans studied abrasion in archeological skeletons from Arkansas, USA. A majority of teeth had dentin exposure (62%) (q. acc. Ortner 2002). In the present study, dental wear is found in 88.3 % of the first maxillary molars examined, and 66 % of the teeth show dentin exposure. This finding is similar to abrasion among modern non-Western groups, such as the Australian Aborigines (Ortner 2002).
4.3. Much of the earlier literature on the dental paleopathology of dental caries is descriptive, which focuses on the history and antiquity of dental caries. In the more recent literature, a new emphasis has emerged on the difference in caries frequency between populations, with caries as an indicator of varying food resources, as in the nutritional differences between hunter-gatherers and agriculturalists. Caries frequency is low among hunter-gatherers (approximately two to three lesions per mouth) and more than twice as high among agriculturists. Both malnutrition affecting tooth development and higher carbohydrates in the diet have been invoked to explain the higher caries frequency in agricultural populations (Ortner 2002). In this study none of the first maxillary molars show occlusal surface caries but majority of the teeth exhibit considerable dental wear. This could be due to coarse particles in the food and low concentration of carbohydrates in the diet. Probably the occlusal surfaces had been ground away before dental caries could develop. The flat attrition facets sometimes found also indicate that bruxism existed in those days.
4.4. Most endodontic and dental anatomy texts describe the human maxillary first molar as having three roots and three or four root canals (Fava 2001, Ng et al. 2001, Wasti et al. 2001). Maxillary first molars with a single buccal root have not been described in the medical literature. However, aberrations such as four (Christie et al. 1991) and five (Fahid and Taintor 1988) roots with a corresponding number of root canals have been discussed. Cases of fused buccal roots have been described in textbooks (Fava 2001). Pecora found fused buccal roots in 7.9% of human maxillary first molars, whilst Sabala reported only 0.4% with the same abnormality (q. acc. Fava 2001). Al Shalabi et al. (2000) mention a fusion of the distobuccal and palatal root in one of 83 extracted maxillary first molars in an Irish population sample. De Moor (2002) describes two cases of the first maxillary molars with this kind of fusion. The classification of root numbers and shapes is difficult, owing to the lack of generally accepted guidelines. It is difficult to distinguish between roots that are fused or not fused. Ross and Evanchik (1981) regarded roots as 'fused' even if fusion occurred only in the apical, middle, or cervical one-third of the roots. In this study we regarded roots as fused if fusion occurred in more than two-third of the roots. Ross and Evanchik (1981) report eight percent fused roots in maxillary first molars in a Caucasian population. The archeological first maxillary molars show an even higher tendency to posses fused roots, especially in female teeth. In two cases mesiobuccal and palatal fused roots were found, which has never been reported in medical literature.
4.5. Studies on the root and canal anatomy were carried out early in the twentieth century using dye placement and sectioning methods. Hess, in particular, discovered many lateral canals, confluences, anastomoses, and other interesting examples of unusual anatomy (q. acc. Weine et al. 1999). These results were considered to be accurate and had considerable influence in restorative and endodontic treatments for many years. The complexity of mesiobuccal roots in the first maxillary molars, first noted in 1925, later become the focus of more detailed and repeated investigations following the study of Weine (q. acc. Weine et al. 1999). These studies have shown that the majority of maxillary first molars have an additional mesiobuccal root canal. Finally, in 1969, it was reported that more than 50% of maxillary first molars possess two canals in the mesiobuccal radix: a mesiopalatal canal in addition to the known mesiobuccal (q. acc. Weine et al. 1999).
4.6. There is a lack of consistency, however, in the reported prevalence of second mesiobuccal canals in medical literature. For example, Kulild and Peters (1990) observed a second mesiobuccal canal in 96% of first maxillary molars, Fogel et al. (1994) in 71% and Imura et al. (1998) in 52%. These differences may be due to the study design, method of canal identification or genuine differences between the samples under investigation.
4.7. In this study it was not possibile to research canal types. Despite the fact that radiographs were taken from each tooth, the degree of mineralisation of dental hard tissues and obliteration of the pulp chamber made it impossible to identify the subtle canal system; it was only the possibile to examine the number and position of apical foramuna per root.
4.8. In Caucasian teeth, most second mesiobuccal canals join the main mesiobuccal canal and both exit through one apical foramen (Alavi et al. 2002). In the archeological samples a high prevalence of two or more separate foramina in mesiobuccal roots is noted in the first maxillary molars, which corresponds with type III or IV in Wein's classification. The investigations of Imura et al. (1998) and Alavi et al. (2002) reported that the higher prevalence of two separate foramina in mesiobuccal roots might be a Mongoloid trait. Of the 330 roots examined, 120 (36.4%) showed the apical foramen to be at the apex, which corresponds with data obtained from other studies (Manning 1990a).
5.2. Considerable dental wear and lack of caries in the teeth examined suggest that the ancient populations consumed food material that contained particles of abrasives, and a low concentration of carbohydrates.
5.3. Despite the complicated root and canal anatomy of molars that has been described recently, the prevalence of four or more apical foramina in archeological maxillary first molars, and the presence of a high percentage of fused roots, suggests that morphology and anatomy of these teeth was as complicated in the XII -XIV centuries as teeth are today.
Ortner DJ (2002) Dental Disease and Miscellaneous Pathological Conditions of Jaws. Identification of pathological conditions in human skeletal remains. Academic Press, An imprint of Elsevier Science, Amsterdam: 589-608