The incisal guidance angle (IGA)
is related to temporomandibular joint (TMJ), and changes to the IGA
are often involved in the prosthetic and orthodontic treatment of
anterior teeth. However, the influence of incisal guidance on the
growth, development and remodelling of the TMJ is not yet clear.
from a recent study published in the BMC Oral Health reveal
that articular fossa of patients with shallower incisal guidance
changed to a flatter shape with age, whereas the condylar anterior
slope and articular eminence of patients with steeper incisal
guidance changed towards a steeper alignment, thereby indicating a
correlation between incisal guidance angle and temporomandibular
Li and associates from the Stomatological Hospital of Chongqing
Medical University, Chongqing, China aimed to investigate age-related
morphological differences in the temporomandibular joint in subjects
with different incisal guidance angle.
computed tomography (CBCT) images of 274 patients were included
(group 1, IGA < 45°; group 2, 45° ≤ IGA ≤ 60°; group 3, IGA > 60°). Each group was then divided into 4 age
groups (group a, 6–12 years; group b, 13–16 years; group c, 17–25
years; group d, 26–33 years). The joint morphology was assessed by
linear measurements, angular measurements, and subjective
evaluations. The incisal guidance angle and occlusal plane angle were
following findings were drawn-
Anterior inclination of condyle (AIC) increased with age in the three
IGA groups but decreased from 17 years onward in group 2 (P < 0.05).
In the age groups analysis, the anterior inclination of condyle in
group 1 was smaller than that in group 3 but larger than that in
group 2 (P > 0.05).
Articular eminence inclination (AEI) decreased with age in group 1
(P = 0.027) but increased with age in group 3 (P = 0.053).
The articular eminence inclination in group 2 was larger than that in
group 1 at 17–25 years (P = 0.046), and it was larger in group
3 than in group 1 at 26–33 years (P = 0.047).
guidance angle had a weak
correlation with articular
(P < 0.05).
it was concluded that “patients with different incisal guidance
have different condylar and articular fossa shapes, and different
trends with age. Patients with more shallow incisal guidance tended
to have a flatter fossa with age, whereas patients with steeper
incisal guidance had a tendency towards a steeper anterior condylar
slope and increased articular eminence inclination.”
Y., Zhou, W., Wu, Y. et al. The relation between incisal guidance
angle and the growth and development of temporomandibular joint: a
multi-cross-sectional retrospective study. BMC Oral Health 21, 380