Studies of Caries Prevalence in a Medieval Population Gulli Olsson and Soren Sagne

Departments of Oral Radiology and Oral Surgery, University of Gothenburg, Gothenburg, Sweden

Introduction

In investigations of many early population groups, the frequency of carious teeth has been shown to be less than 10 % (3, 5). In various medieval materials in Scandinavia, the frequency of individuals with caries has been between 40 and 60 Ufo (4, 10, 13, 19). Thus, the incidence of caries during the Middle Ages has been shown to have been clearly less than that in modern man in the Scandinavian countries. However, the recording of caries in exhumed material has been stated to be subject to special sources of error. Thus, the occurence of post-mortem defects has been reported to yield an erroneous frequency of caries (5, 18). However, other investigators consider that it is quite possible to distinguish between artefacts and real caries (13, 14, 19). The question of whether teeth missing intra vitam can affect the values for the frequency of caries in a skull material has interested a large number of investigators. Thus, MELLQVIST & SANDBERG (13) have classified a tooth missing intra vitam as carious when other causes, such as "senile atrophy, pyorrhoea, trauma, infection after abrasion to the pulp, impaction or underdevelopment of teeth" could be excluded. BRINCH & MOLLERCHRISTENSEN (4) have also pointed out that consideration must be given to the frequency of teeth missing intra vitam in describing the incidence of caries. On the basis of his studies of an early British population, HARDWICK (8) has suggested that 25 Ufo of the missing teeth may be expected to have been lost on account of caries when the proportion of carious teeth is below 5 Ufo and 33 % lost for the same reason when the frequency of caries is 5-20 Ufo. SW ARDSTEDT (19) analysed the cause of the tooth 12

losses by observing the adjacent and homologous teeth, the character of the bite, etc. He stated that marginal bone destruction seemed to be the most common reason for tooth loss but that teeth missing intra vitam might to some extent affect the frequency of caries. The significance of post-mortem loss, as regards the frequency of caries, has also been studied. Thus, BRINCH & MOLLER-CHRISTENSEN (4) noted that cases of extensive losses of teeth had a lower frequency of caries than cases of well-preserved bites. These authors have also shown that comparisons between the caries frequencies of different materials cannot be made without taking into account both teeth missing intra vitam and teeth lost post mortem. They have also suggested, as an aid in this connection, the calculation of various indices, such as the Comparative Dental Index (c. D. I. = the percentage of existing erupted teeth in relation to the optimal number 32). During excavations in Lund in southern Sweden, a skeletal material dating from four different periods during the Middle Ages was collected (1). The sexes and ages of the skeletons in this material have been previously determined and studies have been made of the dental status, the attrition and the tooth, jaw and skull dimensions (16). The aim of this investigation was to record, by direct inspection and by radiography, the incidence of caries in a medieval population in southern Sweden, to assess whether the incidence and localization of caries had changed during the Middle Ages and to study how the results of caries investigations of earlier populations may be influenced by the state of preservation of the material. Dentomaxillofac. Radial. 5:12-18 (1976)

Table 1: Distribution of the skull material by sex, age and period. Age-groups according to MARTIN (11).

Period

I (1020-1050) n = 5

Sex

Infant I

Infant II

Juvenile

Adult

Mature

Senile

0-7

7-14

14-20

20-40

40-60

60-

years

years

years

years

years

years

Men Women

II (1060-1160) n = 64

Men Women Sex not determined

III (1160-1200) n 10

=

3

3 1

Sex not determined

2

4

1

24 10

1

3

1

1

1

16

40 14

3

10

7 1

1

2

13 10

7 5

Men Women

Total

1

9 1

Sex not determined IV (1200-1536) n 43

=

Men Women Sex not determined

Total

1 2

1

1

1

4

5

6

73

Material and methods The material for the caries investigation consisted of the tooth-bearing regions of 122 individual skeletons dating from the Middle Ages. Three of the individuals had only primary teeth. The distribution by sex, age and period is given in Table 1. The caries was recorded by direct inspection and radiography. Radiography has proved to be an essential complement to clinical examination in recording caries in approximal tooth surfaces (2, 9, 17). Similar conditions would seem to apply in recording caries in skull materials. A straight and a curved probe were used in the direct examination. Wherever possible, the teeth were removed from the alveoli for ex-

21 17 5

33

1

122

amination. Caries was recorded only in cases of loss of substance which could be excluded as being due to postmortem damage, tooth fracture or attrition. In cases of large, continous defects due to caries, only one surface was recorded as being damaged, and an attempt was made to decide on which surface the primary attack took place. In cases of crowns totally destroyed by caries, occlusal caries was stated to be present. The recording was checked and supplemented after removing the calculus. In the radiographic examination of teeth and alveolar processes, a Siemens Roentgenkugel (60 kV, 10 rnA) was used, with total filtration equivalent to 2 mm of aluminium. A primary aperture was used, as in ordinary intra-oral radiography. The X-ray apparatus was fitted 13

Table 2: Frequencies of teeth with caries and individuals with carious teeth. Sex, age, periods and whole

material. Sex Men WC:-o-m-e-n --

Juvenile

Age .---:----::--::--Adult Mature

Frequency of teeth affected by caries, 0J0

5.3

7.2

8.3

5.3

6.7

Frequency of individuals with carious teeth, 0J0

52.1

54.5

50.0

47.9

60.0

with a long cone, in which the distance between the tip of the focussing cone and the focus is 30 em. Kodak Ultra-speed film in the 3 X 4 em format was used. Parallelism between tooth and film and the direction of the beam at right angles to them could be secured in the lower jaw by fixing the film to the tooth row. In the upper jaw, where the correct positioning of the film is often jeopardized by narrow and low palatal arches, a holder was used ad modum EGGEN (6), in order to obtain the best possible positional relation between tooth and film. Thus, the projection of the tooth crowns corresponded to that used in an ordinary bite-wing investigation. Seven exposures were made in both the upper and the lower jaw, comprising the molars, the premolars, the cuspid region on each side and the incisor areas. The exposure time was the same for all groups of teeth. The same X-ray apparatus was used for all exposures and only one investigator carried out all the exposures and adjustments. All the exposed films underwent the standardized dark-room treatment. The films were mounted in light-proof frames, as in the usual examination of X-ray films. They were examined at a light table with the aid of binoculars by the method of MA TTSSON (12) and the findings were entered on a standard form. Double determinations were made in 10 randomly selected cases. The findings on direct inspection and by radiography were collated for each individual. Frequencies of carious teeth (number of teeth with caries/teeth examined) were calculated for individual teeth and for different groups in the material. The frequency of individuals with caries was calculated. The distribution of the caries lesions between different parts of the tooth crown (occlusal, mesial, distal, buccal or 14

Period

Whole material

II

III

IV

4.2

5.5

8.1

5.7

-43.8 60.055.8

47.5

lingual surfaces) and the root was analysed. The C.D.!. was calculated for each of the 119 individuals who had at least one permanent tooth. The mean values and frequencies of caries and the C.D.I. were calculated for the whole material and for men and women, agegroups and periods of time. A statistical analysis of the differences between men and women, between the Adult and Mature age-groups and between Periods II and IV was based on the number of carious teeth per individual and was performed by using Pitman's non-parametric correlation test. Results In the double radiographic check of 10 randomly selected individuals, a discrepancy of 1 individual was observed, which meant that there was 90 % agreement. Caries was observed to be present in 142 out of 2513 permanent teeth, which signified a frequency of 5.7 0/0. For men, the frequency was 5.3 Ofo and for women, 7.2 Ofo (Table 2), but this difference between the sexes was not statistically significant. There was no caries in individuals belonging to the age-groups Infant I and II. The frequency for Juveniles was somewhat higher than for Adult and Mature individuals. As the number of Juveniles was small, no statistical analysis of these differences was carried out. The somewhat higher frequency for Mature than for Adult individuals was not significant. A tendency to a higher frequency was noted towards later periods. Thus, the difference between Periods II and IV was significant (Table 2). In 47.5 Ofo of the individuals, there was one or more carious teeth. There were no differences as between the sexes. Mature individuals displayed higher frequencies than Adult. The frequency was lower for the early Period II than for the later periods (Table 2).

Table 3: Distribution of caries lesions between different tooth surfaces as percentages of surfaces examined. u. j.

= upper jaw, 1. j. = lower jaw Occlusal

Men

Mesial u.], 1. j.

u.].

1. j.

1.4

2.4

3.3 1.5

Women

2.9

3.0

Juvenile

5.1

6.8

0.9

Distal u.j. 1. j.

Buccal u.].

1. j.

2.4

0.7

0.5

4.1

1.0

1.8

Root u.j.

1. j. 0.1

0.3

0.3 1.7

2.7

Adult

1.9

2.9

2.4

0.6

1.9

0.5

0.9

Mature

1.1

0.8

3.7

0.8

6.3

1.6

0.5

Period II

1.7

1.5

2.2

0.7

2.4

0.5

0.7

Period IV

2.5

3.9

2.9

0.4

3.8

1.2

1.4

Whole material

1.8

2.5

2.6

0.6

2.8

0.8

0.8

Caries was mainly present in the lateral teeth. The front teeth were quite free from caries, except for a few cuspids in the upper jaw. A tendency to higher frequencies appeared for the left-hand side, both in the upper and in the lower jaw. In the upper jaw, the percentage of carious teeth was somewhat higher than in the lower jaw (Fig. 1). Men and

Lingual u.j. 1. j.

0.2

0.4

0.3

0.2

0.2

women had relatively similar distributions of the damage due to caries (Fig. 2). Differences between the Adult and Mature age-groups could be observed in the lateral parts of the upper jaw, while there were no differences in the lower jaw (Fig. 3). In Period IV, there was a clearly higher frequency of carious teeth in the lateral parts than in Period II (Fig. 4).

"'0"

-Adull

--_·_·-·-Mel\M"e

Fig. 1: Frequency of caries for different teeth.

Fig. 3: Frequency of caries for different teeth.

Whole material.

Adult and Mature individuals.

'X, • ...•

Studies of caries prevalence in a medieval population.

Studies of Caries Prevalence in a Medieval Population Gulli Olsson and Soren Sagne Departments of Oral Radiology and Oral Surgery, University of Goth...
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