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)