Automatic exposure compensation in intraoral digital radiography: effect on the gray values of dental tissues

BMC Medical Imaging

Table.3 Mean and standard deviation (SD) of the gray values of dental tissues in the Express radiographic system distributed according to the group, exposure time, and kilovoltage

Dental tissue	Group	t = 0.06 s		t = 0.10 s		t = 0.16 s
Dental tissue	Group	60 kV	70 kV	60 kV	70 kV	60 kV	70 kV
Enamel	Control	227.5 (8.4) Aa	225.1 (10.3) Aab	226.0 (9.1) Aab	215.5 (10.1) Ac	220.5 (10.8) Ab	213.1 (10.8) Ac
Enamel	High-density	224.2 (10.4) Aa	217.2 (9.6) Bc	224.0 (10) Aab	208.5 (10.7) Bd	217.7 (11.5) Ab	205.4 (8.3) Bd
Crown dentine	Control	192.4 (13.4) Aa	190.5 (10.4) Aab	193.2 (11.6) Aa	181.0 (11.1) Ac	185.0 (8.8) Abc	185.2 (16) Abc
Crown dentine	High-density	187.7 (12.3) Aa	182.4 (9.7) Bab	189.5 (11) Aa	173.4 (8.4) Bc	180.2 (9) Abc	177.1 (11) Bbc
Root dentine	Control	172.4 (28.8) Aa	169.6 (22.4) Aa	171.9 (26.6) Aa	166.5 (21.4) Aa	167.7 (22.7) Aa	171.6 (26.4) Aa
Root dentine	High-density	168.5 (25.3) Aa	162.7 (22.9) Aa	167.7 (25.2) Aa	158.4 (19.4) Aa	162.3 (21.5) Aa	164.1 (22.1) Aa
Pulp	Control	83.5 (24.3) Aa	95.6 (20.1) Aa	90.5 (24.5) Aa	98.1 (17.6) Aa	93.4 (20.8) Aa	92.4 21.5) Aa
Pulp	High-density	77.4 (22.4) Aa	89.4 (20.8) Aa	82.5 (23.2) Aa	93.6 (17.6) Aa	88.9 (19.8) Aa	88.3 (19.8) Aa

Different uppercase letters indicate a statistical difference between the control and high-density groups, within each dental tissue (vertical comparisons)
Different lowercase letters indicate a statistical difference between kV at the same exposure time and between exposure times at the same kV, within each group (horizontal comparisons)

ISSN: 1471-2342