Table 3. Comparison of each molar length, of the total molar field length, and the total length of M1+ M2, between wild-type (WT) mice and RSk2-/Y mutant mice with 3 or 4 molars.

	Mandibular molars WT	Mandibular molars Mutant 3M	Mandibular molars Mutant 4M	Maxillary molars WT	Maxillary molars Mutant 3M	Maxillary molars Mutant 4M
Mean ST			0.60			0.74
STD			0.01			0.02
Mean M1	1.44	1.37	1.14	1.56	1.38	1.14
STD	0.03	0.11	0.05	0.07	0.10	0.09
p-value		0.23	0.0004		0.01	0.001
Mean M2	0.89	0.85	0.79	0.92	0.85	0.82
STD	0.03	0.02	0.03	0.02	0.04	0.05
p-value		0.003	0.004		0.02	0.01
Mean M3	0.59	0.53	0.49	0.60	0.63	0.63
STD	0.02	0.03	0.04	0.03	0.03	0.05
p-value		0.0002	0.0004		0.96	0.15
Total	2.93	2.75	2.88	3.08	2.85	3.31
STD	0.04	0.15	0.28	0.10	0.13	0.06
p-value		0.0008	0.36		0.01	0.001
M1+ M2	2.33	2.10	2.15	2.48	2.30	1.96
STD	0.04	0.16	0.21	0.08	0.14	0.13
p-value		0.03	0.004		0.002	0.001

M1 size is reduced in mutants with 4 molars both in mandible and maxilla, but only in the maxilla of mutants showing 3 molars. M2 is reduced both in maxilla and mandible whatever the molar mutant phenotype. M3 mesiodistal dimension is reduced only in the mandible, irrespective of the presence of 3 or 4 molars. The total size of the molar field is reduced in the mandible and maxilla in mutant with 3 molars. The total size of the molar field is significantly increased in the maxilla in mutants with 4 molars. The total size of M1+M2 was always reduced when compared to the wild type value. All distances are in millimeters. Significant p-values are shown in bold.

M1 : molar 1; M2 : molar 2; M3 : molar 3; ST : supplementary tooth in front of M1; STD : standard deviation; Mutant 3M : mutant with 3 molars; Mutant 4M : mutant with 4 molars; Total : total length of all molars in the molar field.