Comparative dental development and microstructure of ... - UCL

180 A. D. BEYNON ET AL.
Table 2
Index No. of
tooth section
m=mesial;
d=distal
Tooth
type
Occlusal
enamel
thickness
along prisms
(microns)
Cuspal
formation time
(=occl. enam. thick/4·9 μm)
(days)
Total
striae
counts
(Lingual)
Total
striae
counts
(Buccal)
Range of
lateral enamel
form. time
estimates
(days)
Range of
total crown
formation
estimates
(days)
Crown formation
time (cusp+lat.).
The lateral aspect
or cusp used is
shown in parentheses
(years)
Juvenile
P. heseloni
HT3/91A LR I1 400 82 40+ 200 282 0·77+ (b)
HT3/91B LR I2 600 122 35+ 175 297 0·81+ (b)
HT3/91D LR dm1
HT3/91E m LR dm2
HT3/91F m LR M1 780 159
HT3/91G m LR M2 900 184 24+ 22+ 120 304 0·8+ (mb)
Adult
P. heseloni
HT2/91A LR C 750 153 142+ 710 863 2·4+ (b)
HT2/91B LR P4 750 153 80 109 400–545 553–698 1·9 (b)
HT2/91C m LR M1 800 163 87 54+ 435–270 433–598
HT2/91C d LR M1 800 163 66+ 51+ 255–330 418–493 1·2 (mb)
HT2/91D m LR M2 (900) (184) 70+ 66+ 330–350 514–534 1·4 (mb)
HT2/91D d LR M2 77 385
HT2/91E m LR M3 1400 286 65+ 61+ 305–325 591–611 1·6 (mb)
HT2/91E d LR M3 1400 286 82 410 696
Adult
P. nyanzae
RU 1721 m URM1 1570 320 69 414 734 2·0 (mb)
RU 1721 d URM1 1600 327 56 336 663 1·8 (db)
RU 1695 m LRM2 1600 327 72 432 759 2·1 (mb)
RU 1695 d LRM2 1717 350 63 96 378–576 728–926 2·0 (dl)–2·5 (db)
The index number of each ground section of each Proconsul tooth appears in column 1. Sections through the mesial or distal cusps of molars are indicated (m
or d). Cuspal formation times were calculated by dividing occlusal enamel thickness by the mean cuspal daily rate, 4·9 μm. Stria counts made on buccal (b) and
lingual (l) aspects of mesial and distal sections are shown and a range indicated when possible. Ranges of total crown formation times are indicated in column
8 but in the last column (9) molar crown formation times in P. heseloni are calculated using the mesiobuccal cusp only (mesiobuccal cuspal enamel
formation+mesiobuccal lateral enamel formation) since this cusp forms first in molar teeth. In one worn M 2 section (HT2/91D dist.) no cuspal enamel formation
time could be estimated and values for M 2 were used for the unworn M 2 section HT3/91G and are bracketed in columns 3 and 4. Molar crown formation times
in P. nyanzae are calculated using all measures of cuspal enamel thickness possible in all cusps as well as all corresponding stria counts on all aspects of the sections
available.