An in vitro study evaluating the effect of ferrule design on the fracture resistance of endodontically treated mandibular premolars after simulated crown lengthening or forced eruption methods

Table 1 Mean dimensions (mm) of randomly assigned mandibular first premolar roots in each group

Group (N = 40)	Root Length^a	Width of canal wall sites, and roots, at root face^a
Group (N = 40)	Root Length^a	Mesial	Buccal	Distal	Lingual	M-D	B-L
F0	15.12 (0.36)	2.19 (0.30)	2.55 (0.15)	2.17 (0.41)	2.36 (0.26)	6.18 (0.97)	8.16 (0.73)
CL/F1	15.16 (0.35)	2.04 (0.41)	2.40 (0.43)	1.92 (0.19)	2.43 (0.20)	5.66 (0.58)	7.88 (0.63)
CL/F2	15.18 (0.27)	2.47 (0.54)	2.63 (0.37)	2.12 (0.33)	2.60 (0.34)	6.40 (0.77)	8.25 (0.52)
OE/F1	15.12 (0.26)	2.06 (0.37)	2.47 (0.27)	2.00 (0.42)	2.52 (0.38)	5.89 (0.96)	8.07 (0.70)
OE/F2	15.19 (0.42)	2.18 (0.30)	2.65 (0.30)	2.11 (0.33)	2.66 (0.36)	6.26 (0.60)	8.13 (0.35)
1-way ANOVA	F = 0.083 P = 0.987	F = 1.502 P = 0.223	F = 0.823 P = 0.519	F = 0.691 P = 0.603	F = 1.2 P = 0.328	F = 1.140 P = 0.354	F = 0.412 P = 0.799

Group F0: glass fiber post-core with 0.0 mm buccal and 2.0 mm lingual ferrule lengths, as control; Group CL/F1: glass fiber post-core with simulated crown lengthening and 1.0 mm buccal and 3.0 mm lingual ferrule lengths; Group CL/F2: glass fiber post-core with simulated crown lengthening and 2.0 mm buccal and 4.0 mm lingual ferrule lengths; Group OE/F1: glass fiber post-core with simulated orthodontic forced tooth eruption and 1.0 mm buccal and 3.0 mm lingual ferrule lengths; Group OE/F2: glass fiber post-core with simulated orthodontic forced tooth eruption and 2.0 mm buccal and 4.0 mm lingual ferrule lengths
^aMean (Standard Deviation); M-D: mesiodistal root width; B-L: buccolingual root width

ISSN: 1472-6831