DISCUSSION
KMs or ‘rosette formation’ is a rare phenomemon first described in 1973
where the molars are in occlusion within a single, enlarged follicular
space.13 The incidence of KMs has been reported to be
0.06%, being higher in males with an age range of 13-58
years.5,8 Majority are unilateral and occur in the
mandible, although bilateral cases have been
reported.6,13-19 In the present case, the patient
presented with bilateral KMs as an incidental finding. Past medical
history may be significant in the occurrence of KMs which may imply that
they are a manifestation of diseases rather than independent entities
occurring in otherwise healthy individuals. Notably,
mucopolysaccharidosis is implicated in some cases with
KMs.18 Existing literature was reviewed extensively
and a summary of the type of KMs, symptoms, associated disease and
treatment presented (Table 1).
Management of symptomatic KMs necessitates surgical intervention whilst
that of asymptomatic KMs entails maintenance of the molars within the
jaw or surgical disimpaction.20 Maintenance could lead
to complications such as reduction of mandibular bone mass over time
hence increasing risk of fracture, dentigerous cyst formation, root
resorption, pericoronitis, compression of the inferior alveolar nerve
(IAN) leading to paresthesia of the lip and functional
impairment.7,15,21,22 On the other hand, numerous
complications may occur intra-operatively and post-operatively following
surgical disimpaction. These include fracture of the mandible due to
thinning of cortical bone, damage to the IAN and lingual nerve,
temporomandibular joint disorders and
infections.14,15,19,23,24,25,26 Therefore,
comprehensive clinical and radiographic investigation must be done prior
to management.19 As pertains the current case, there
was contact between 37 and 47 root apices with the IAN and curvature of
the tooth roots. Additionally, the distance to the inferior border of
mandible was considerably reduced hence increasing the risk of fracture
during surgical disimpaction. These findings informed the decision to
maintain the KMs within the jaw and review the patient annually.
Anatomic variations of maxillary second premolars are well documented in
the literature, however, trifurcated second premolars are
rare.27-31 (Table 2) Knowledge of such
variation is crucial during endodontic treatment of the premolar which
may necessitate modification of the typical access cavity and consequent
technique of management.28,32 Visualization of the
third root (palatal root) of the premolar can be challenging on plain
radiographs due to superimposition of the buccal
roots.33,34 The panoramic image in this case
(figure 1 ) is a good example of the latter, whereby
superimposition of the mesiobuccal roots concealed the palatal roots. If
the mesiodistal width of the mid-root image is equal to or greater than
the mesiodistal width of the crown, three canals should be
suspected.35 The clinician should have a thorough
understanding of the anatomy of the pulp chamber and root canal system
along with possible departures from the norm prior to performing any
endodontic therapy. In addition, good illumination and magnification can
greatly improve visualization of canals and improve management of
complex root canal systems.36