Clinically, central incisors fractures caused by fron- tal impacts fall into three categories according to the direction and position of fracture lines: (a) horizontal crown fracture involving the mesio-distal angles or (oblique fracture of the whole incisal edge) (b) oblique fractures involving the mesial angle of the central in- cisors (c) oblique fractures involving the distal angle of the central incisors.
The anatomy of the incisal edge of the central incisor reveals that the distal incisal angle is thicker and more rounded than the mesial incisal angle, which consequently makes it prone to fracture with relatively less impact forces than the distal angle.17 Therefore patterns of fractures that involves the mesial incisal edges (like fracture patterns 1,2 and 3) is almost twice the incidence of those that involves the distal incisal angles like fracture patterns.4-7
The parameters (tibiae dimensions) used in the morphometrical analysis were: a) total length; b)proximal width; c) diaphisary width; d) distal width; e) proximal angle and distal angle. All of the macroscopical measurements were made to the nearest 0.01 mm using callipers.
All of the measurements for parameters; total lenght, proximal whidth, proximal and distal angle of tibiae in the ER and PR groups were significantly smaller than those of the control group, with the difference being greater in the PR group.