Maxillary second premolar — buccopalatal oval access with a single central orifice
Reference model: “Maxillary Second Premolar”, University of Dundee School of Dentistry (Sketchfab), CC BY 4.0. Rendered and adapted by EndoGuide.
Average Length21.5 mm
Root Development14 years
Universal #4, 13
FDI #15, 25
Access Cavity Design
ShapeOvoid
OrientationBuccopalatal; slightly wider mesiodistally than first premolar, reflecting more symmetrical crown
Entry PointCentral sulcus of occlusal surface
Landmarks
Cusp tips define buccopalatal extension
Central sulcus as longitudinal guide
Do Not Invade
Mesial and distal marginal ridges (preserve structural integrity)
Canal Anatomy
Configurations
1 canal (Vertucci Type I)56-75%
2 canals joining apically (Vertucci Type II, 2-1)20-24%
2 separate canals (Vertucci Type IV, 2-2)10-20%
3 canals (Vertucci Type VIII)0.66-2%
Canal Positions
MCMain Canal
Often oval or ribbon-shaped (band-shaped), may appear as buccopalatal slot — always explore for second canal
BBuccal Canal
When 2 canals present; beneath buccal cusp tip
PPalatal Canal
When 2 canals present; beneath palatal cusp tip
Danger Zones
⚠Mesial concavity — similar to first premolar but generally less pronounced
⚠Strip perforation risk when 2-rooted, especially with aggressive buccal canal shaping
Clinical Tips
Warning
Most anatomically variable maxillary premolar: Type I (56-75%), Type II (20-24%), Type IV (10-20%), Type VIII (0.66-2%)
Warning
Slot-shaped orifice = assume 2 canals (Type II or IV) until proven otherwise — explore both walls
Technique
NaOCl bubble test at slot-shaped orifice helps confirm canal bifurcation
Anatomical Variations
Vertucci Type II (2-1 configuration)
20-24%
Two canals originating from pulp chamber that merge into one canal before the apex with a single foramen. Isthmus region between canals harbors tissue.
Access Modification:Wider buccopalatal access to locate both orifices; NaOCl bubble test at isthmus; thorough irrigation of connecting area
Vertucci Type IV (2-2 configuration)
10-20%
Two separate canals from pulp chamber to apex, each with its own foramen. May have separate roots or share a single root.
Access Modification:Extend access buccopalatally to achieve straight-line access to both canals
Three Canals (Type VIII)
0.66-2% (rare)
Three separate canals (resembling molar configuration). Documented in case reports across multiple populations.
