Kalburge V, Yakub SS, Kalburge J, Hiremath H, Chandurkar A. A comparative evaluation of fracture resistance of endodontically treated teeth, with variable marginal ridge thicknesses, restored with composite resin and composite resin reinforced with Ribbond: An in vitro study. Indian J Dent Res 2013;24:193-8
Background: The anatomic shape of maxillary premolars show a
tendency towards separation of their cusps during mastication after
endodontic treatment. Preservation of the marginal ridge of
endodontically treated and restored premolars can act as a strengthening
factor and improve the fracture resistance.
evaluate the effect of varying thickness of marginal ridge on the
fracture resistance of endodontically treated maxillary premolars
restored with composite and Ribbond reinforced composites.
Materials and Methods: One hundred and twenty, freshly extracted, non carious human mature maxillary premolars were selected for this experimental in vitro study. The teeth were randomly assigned in to twelve groups ( n
= 10). Group 1 received no preparation. All the premolars in other
groups were root canal treated. In subgroups of 3 and 4, DO cavities
were prepared while MOD cavities were prepared for all subgroups of
group 2, the dimensions of the proximal boxes were kept uniform. In
group 3 and 4 the dimensions of the mesial marginal ridge were measured
using a digital Vernier caliper as 2 mm, 1.5 mm, 1 mm and 0.5 mm in the
respective subgroups. All samples in groups 2.2 and all the subgroups of
3 were restored with a dentin bonding agent and resin composite. The
teeth in group 2.3 and all subgroups of 4 were restored with composite
reinforced with Ribbond fibers. The premolars were submitted to axial
compression up to failure at 45 degree angle to a palatal cusp in
universal testing machine. The mean load necessary to fracture was
recorded in Newtons and the data was analysed.
was a highly significant difference between mean values of force
required to fracture teeth in group 1 and all subgroups of group 2, 3
and 4 (i.e., P < 0.01)
Conclusion: On the basis of
static loading, preserving the mesial marginal ridge with thicknesses of
mm, 1.5 mm, 1 mm and 0.5 mm, composite restored and Ribbond reinforced
composite restored maxillary premolars can help preserve the fracture
resistance of teeth.