04-05-2012 review on radix entomolaris and paramolaris
TRANSCRIPT
Review on Radix Entomolaris and Paramolaris
Introduction Normal canal anatomy of mandibular
first molar 2 roots 3 canals
Radix entomolaris and paramolaris An additional third root is called the radix
entomolaris. This supernumerary root is located distolingually in mandibular molars, mainly first molars.
An additional root at the mesiobuccal side is called the radix paramolaris (RP)
Incidence: The incidence of the presence of a third
distolingual root has been linked to specific ethnic groups.
The Mongoloid population exhibited significantly more mandibular first molars with 3 roots, with a 3:1 ratio when compared with Caucasians and African Americans
Most of the literature concurs that the presence of a third root is an expected anatomical characteristic of Mongoloid, Native American, Eskimo, and Chinese populations with a frequency of 5-30%.
In African populations a maximum frequency of 3% is found
Eurasian and Indian populations the frequency is less than 5% (Tratman EK. Three-rooted lower molars in man and their racial distribution. Br Dent J 1938;64:264 –74.)
In Caucasians it is 3.4 to 4.2%
Prevalence of Three-rooted Mandibular Permanent First Molars among the Indian Population(J Endod 2010;36:1302–1306) The prevalence of three-rooted
mandibular first molars was 5.97% for all patients and 4.55% for all teeth, respectively.
The incidence of bilateral symmetrical distribution was 37.14%.
The incidence was 6.88% for female patients and 4.89% for male patients
4.94% for the right side and 4.17% for the left side, respectively
Etiology: Dysmorphic roots – polygenicity,
atavism eumorphic roots-genetic inheritance
with a high degree of penetrance
Can be found on the first, second and third molars – lesser incidence in 2nd
Bilateral occurrence – 50-67% The prevalence of RP, as observed by Visser, was
found to be 0% for the first mandibular molar, 0.5% for the second and 2% for the third molar.
Morphology: The RE is located distolingually, with its coronal
third completely or partially fixed to the distal root.
The dimensions of the RE can vary from a short conical extension to a ‘mature’ root with normal length and root canal.
In most cases the pulpal extension is radiographically visible.
In general, the RE is smaller than the distobuccal and mesial roots and can be separate from, or partially fused with, the other roots.
ClassificationCarlsen and Alexandersen - four different types of RE according to the location of the cervical part of the RE: Types A and B -distally located cervical part of
the RE with two normal and one normal distal root components, respectively.
Type C - mesially located cervical part Type AC - central location, between the distal
and mesial root components
According to De Moor et al., based on the curvature of the separate RE variants in bucco-lingual orientation, Type I - straight root/root canal, type II -initially curved entrance which
continues as a straight root/root canal. Type III -initial curve in the coronal third of the
root canal and a second curve beginning in the middle and continuing to the apical third
Radix paramolaris: Carlsen and Alexandersen describe two different
types: types A and B. Type A - cervical part is located on the mesial root
complex; Type B - cervical part is located centrally, between the
mesial and distal root complexes.
Diagnosis Clinical inspection – of the tooth crown and
analyzing the cervical morphology of the roots with periodontal probing
‘An extra cusp (tuberculum paramolare) or more prominent occlusal distal or distolingual lobe, in combination with a cervical prominence or convexity, can indicate the presence of an additional root.’
Radiographic diagnosis: Preoperative radiographs-look for unclear view or
outline of the distal root contour or the root canal Angled radiographs – 30° from the mesial or
distal Other options:
CBCT(Detection of Permanent Three-rooted Mandibular First Molars by Cone-Beam Computed Tomography Imaging in Taiwanese Individuals J Endod 2009;35:503–507)
Micro CT Spiral CT
Access opening: Morphology of the pulp floor Modified access opening –
rectangular/trapezoidal Orifice is located distolingual to mesiolingual of
the main distal canal. Distance between the distobuccal and
distolingual orifice - 2.72 +/-0.71mm After access opening – if not visible – probing,
removal of secondary dentin over the orifice Use of visual aids – loupes, microscope
Detection of Permanent Three-rooted Mandibular First Molars by Cone-Beam Computed Tomography Imaging in Taiwanese Individuals (J Endod 2009;35:503–507)
Shaping and cleaning: Stepwise:
Relocation of orifice after secondary dentin removal
Initial exploration with small K files Working length and determination of
curvature Creation of initial glide path Use of flexible rotary NiTi instruments
Implications: Prevalence studies needed to establish
incidence in Indian population Meticulous clinical and radiographic
examination will aid in taking treatment decision
References The Radix Entomolaris and Paramolaris: Clinical Approach in
Endodontics (J Endod 2007;33:58–63) Root Anatomy and Canal Configuration of the Permanent
Mandibular First Molar: A Systematic Review (J Endod 2010;36:1919–1931)
Root Canal Morphology of Permanent Three rooted Mandibular First Molars—Part I: Pulp Floor and Root Canal System (J Endod 2010;36:990–994)
Prevalence of Three-rooted Mandibular Permanent First Molars among the Indian Population (J Endod 2010;36:1302–1306)
Detection of Permanent Three-rooted Mandibular First Molars by Cone-Beam Computed Tomography Imaging in Taiwanese Individuals (J Endod 2009;35:503–507)