4. DISCUSSION
Tiny cracks are common and usually do not cause problems. In such cases
regular checkups are important to manage such problems in early stage.
Various treatment modalities are available for advanced cracks
(incomplete fracture). The choice depends on the location, direction and
extent of the crack. Cracks may be superficial, affecting the cusp of a
tooth or deep to involve the root of the tooth. Some affect only the
enamel; others may extend to the dentin or the pulp. Before treatment,
reduction or elimination of occlusal contacts is essential to avoid an
overload of a split tooth 2.
Tenderness on biting and pain with cold, sweet or hot or a combination
of these are common complains of a cracked tooth. These symptoms can be
explained by the hydrodynamic theory of pain first described by Feiglin4 and substantiated experimentally by Brӓnnstrӧm5. This theory is based on the concept that rapid
movement of dentinal fluid in the dentinal tubules causes pain. This
movement stimulates mechano-receptors in close proximity to the
odontoblast cell body, which then activate delta nerve fibers (faster
myelinated fibers), resulting in a short sharp pain.
Simvastatin is a new therapeutic material in the field of dentistry and
still under dental research. Its structural analogs of HMG-CoA
(3-hydroxy-3-mthylglutaryl-coenzyme A) that are considered to be the
first-line to control hyperlipidemia and it has been recognized as a
safe and low-priced drug with worldwide longtime usage6,7. Moreover, statin has multiple functions including
anti-inflammation, induction of angiogenesis and improvement of the
vascular endothelial cell function. In addition, several statins
products have anabolic effects on bone metabolism 8and promote mineralization in non-mineralizing osteoblasts through
induction of Bone Morphogenic Protein- 2 and osteocalcin9. Simvastatin also proved to promote differentiation
of osteoplastic cells in mice 10.
Crack sealed by dentin is considered the proper biological and
mechanical management of tooth crack. Simvastatin was used in this
clinical report as a intra-canal medicament to seal the tooth crack
because previous experimental studies proved that it can stimulate bone11 and dentin formation 12. Painful
symptoms disappeared during the rest treatment which proved the
therapeutic effects of simvastatin. The exact mechanism or mode of
action of simvastatin in the crack seal is not known. However, the
anti-inflammatory action of statins may explain the rapid relief of pain
after application of the material inside the canal 8.
The use of simvastatin in the current case is considered as an empirical
treatment that was based on experimental studies and further clinical
studies should be conducted for investigation of its side effects and
mode of action before its approval to be used in endodontics. Regardless
the results of this case, the clinicians can apply this approach only
when they have scientific evidence.
CONCLUSION
Fracture is one of the most common causes of tooth loss, therefore, it
is important to avoid or eliminate risk factors which contribute to
tooth fracture. The key factor is early diagnosis and treatment of the
cracks so that they can be halted, or their progression slowed down.
Simvastatin allowed a good management for a case suffered from cracked
tooth.