Management of mandibular first premolars with unique anatomies

Fig. 1

Systematic Review by Kotoor et al. (2013) stated the following incidences in mandibular first premolars:

• 1 root in 97.21%
• 2 canals in 23.55%
• 3 or more canals in 0–5%.

They also stated the incidence of two canals in mandibular first premolars according to ethnicity (insert table)

This case report describes the diagnosis and non-surgical endodontic treatment of 2 mandibular premolars with two and three canals.

Fig. 2

Case 1:

Pre-operative clinical scenario in mandibular left first premolar (tooth 34) with deep class V defect, dislodged restoration and severe nocturnal and spontaneous pain. 

Patient was diagnosed with symptomatic irreversible pulpitis after pulp sensibility testing. 

Fig. 3

Pre-operative IOPA of tooth 34

“Fast break appearance” seen in the middle third of the root.

Single canal leaving the pulp chamber continuing till middle third, then bifurcating in 2 canals with 2 separate portals of exit. 

Fig. 4

Clinical image showing 2 canals in bucco-lingual orientation at level of split in middle third.

2 canals- buccal (B) and lingual (L).

Fig. 5

Master cone fit radiograph 

Fig. 6

Post- obturation radiograph

Vertucci type VII anatomy (1-2-1-2):

1 canal leaving the pulp chamber continuing till middle third, then bifurcating in 2 canals, anastomosing again in the apical third as an isthmus, finally exiting as 2 canals with 2 separate portals of exit. 

Fig. 7

Post- obturation radiograph (inverted)

Pre-requisites:

• Comprehensive pre-operative evaluation using multi- angled radiographs and/or CBCT
• Magnification- dental operating microscope or loupes
• Isolation-rubber dam
• 6,8,10 size K files
• Flexible NiTi files
• Downpack and backfill obturation system

Fig. 8

Sequential steps in negotiating a premolar with bifurcated split 

1. Use round bur to access the pulp chamber
2. Deroof using ultrasonic tip (start X2, Satellac)
3. Refinement of the canal till the level of bifurcation using ultrasonic tip (start X3, Satellac)
4. Insertion of DG 16 probe tip to “catch” the orifices and further refinement in bucco-lingual direction to de-roof orifices if necessary. 
5. Insertion of pre-bent 6K files one at a time into the orifices at the level of split
6. Enlargement of canal orifices and removal of coronal interferences at the level of split. 
7. Negotiation of canals till apex with hand files with gentle watch winding motion followed by rotary files
8. Selection of master GP cones
9. Hybrid obturation with modified downpack till the level of split followed by backfilling with thermoplastic GP till CEJ.

Fig. 9

Case 2:

Patient presented with spontaneous throbbing pain and pain on chewing. 

H/O deep restoration 2 months ago. 

Diagnosis: symptomatic irreversible pulpitis with symptomatic apical periodontitis.

“Fast break” appearance seen in the end of cervical third in pre-operative IOPA.

Fig. 10

Supplemental configuration types to Vertucci's classification (Type IX) as suggested by Sert & Bayirli:

1 canal leaving the pulp chamber continuing till beginning of middle third, then trifurcating in 3 canals and exiting as 3 separate portals of exit. 

3 separate root outlines seen apically.

Fig. 11

Sequential steps in negotiating a premolar with trifurcated split 

1. Trace the root outline to ascertain the number of roots and corresponding root canals. 
2. Use round bur to access the pulp chamber
3. Deroof using ultrasonic tip (start X2, Satellac)
4. Refinement of the canal till the level of trifurcation using ultrasonic tip (start X3, Satellac)
5. Triangular shaped platform should be aimed for when considering a trifurcation. 
6. Insertion of DG 16 probe tip to “catch” the orifices and further refinement in bucco-lingual and mesio-distal  direction to de-roof orifices if necessary. 
7. Insertion of pre-bent 6K files one at a time into the orifices at the level of split
8. Enlargement of canal orifices and removal of coronal interferences at the level of split. 
9. Negotiation of canals till apex with hand files with gentle watch winding motion followed by rotary files
10. 10.Selection of master GP cones
11. 11.Hybrid obturation with modified downpack till the level of trifurcation followed by backfilling with thermoplastic GP till CEJ.