NECESIDADES Y EXPECTATIVAS EN LAS PYME’S DEL SECTOR

The concept o f obtaining data on dental variation via the recording o f the tooth outline and fissure pattern is one which has been developed considerably by dental

anthropologists, particularly in the study o f human evolution. The methods described for this project draw heavily on such studies which are reviewed in Chapter Three.

The recording o f tooth outlines was carried out to allow shape analysis o f the tooth crown outline. Each tooth was recorded using a binocular microscope (Leica Wild M3C/M5) with a drawing tube attachment. Two different microscopes o f this make and model were used in this study. The data from the domestic breed sample were recorded at English Heritage, Ancient Monuments Laboratory, using an M5, while those from the Hakel wild boar sample were recorded using an M3C fi'om the Institute o f Archaeology. There was a slight difference in magnification between the two microscopes (X6 versus

X6.5) but this was not a source o f error as a separate scale bar for each tooth was included in each tracing. The mandible was supported using a clamp attached to a retort stand. The arms o f the clamp were shielded by rubber tubing to ensure that the

mandibular bone was not damaged during the process o f examination. The objective chosen was the lowest for each microscope; X6 or X6.5. Variation in working distance resulted in the actual magnification varying between seven and nine times actual size, so that it was necessary to calibrate the scale for each tracing separately. This was achieved by placing a small section o f graduated paper (strengthened by a card backing) on the occlusal surface o f the crown o f the tooth, held in place with modelling clay.

The tooth was aligned below the microscope so that the occlusal surface was parallel to the objective. This was achieved by altering the orientation o f the tooth as viewed through the microscope, to find the position at which the maximum crown area was visible without any roots coming into view. Maloccluded teeth presented a problem in that the surface o f the tooth and the plane in which the tooth was to be viewed varied considerably, seriously maloccluded specimens were not included in the analysis.

Focusing on an object which had depth presented a problem, as only one part o f the tooth surface would be in sharp focus at one time. This problem was resolved by

focusing on the fissures o f medium depth, at which point both the deeper fissures and the cusps were slightly out o f focus to a similar degree.

With the use o f a drawing tube attachment the outline was traced onto 112gms transparent paper using a 4H graphite pencil. Beneath the transparent paper a sheet o f plain white paper was placed in order to increase the visibility o f the observer’s hand and pencil when looking through the microscope with the drawing tube aperture open. It was also important to ensure the light sources to the object and the paper were correctly balanced. The paper was fixed to the bench using masking tape to prevent movement.

Any damage which the tooth had sustained during life, due to occlusion and attrition, was marked onto the tracing. Such areas were easily identified as the exposed dentine was o f a more yellowish colour than the enamel. Enamel wear was visible but more difficult to identify than dentine exposure. The tracings o f the teeth were then digitised using the Optimas Bioscan software, but before this was done the tracings were inked in to produce a greater contrast when placed under the camera for digitisation.

One problem which was noted in the recording o f the outline o f the tooth was that if a tooth had been subject to inter tooth attrition, chips o f enamel had often been lost from the crown. The result was that part o f the perimeter o f the tooth outline was missing. Following the protocol o f Wood and Uytterschaut (1987) in cases where the damage was slight enough that the contour o f the outline was still obvious, the missing parts were reconstructed. If the damage was more severe and the outline could not be reasonably reconstructed, then the specimen was not included in the analysis. This problem was not seen to any great extent in the modem domestic specimens within the English Heritage collection. The oldest age group examined in the Hakel collection, i.e. those aged between 13 and 15 months, were found to be subject to more severe chipping and thus excluded from analysis with the methods derived from the data within tracings. In this older age group another problem pertaining to the accurate recording o f dental data was noted. The fourth deciduous premolars which are replaced at around 16 months by the permanent fourth premolars were already showing signs o f resorption o f root tissue. It was felt this may influence some o f the metrical dimensions taken. For example, cervical length for dp4 was not taken in individuals, where the root resorption had reached the CEJ.