MaxillaryOvoid
Maxillary Lateral Incisor
Maxillary Lateral Incisor - Axial View showing ovoid access cavity
Average Length22.0 mm
Root Development11 years
Universal #7, 10
FDI #12, 22
Access Cavity Design
ShapeOvoid
OrientationLonger axis oriented labiopalatally; centered slightly toward incisal on palatal surface
Entry PointPalatal surface, just above cingulum
DimensionsM-D: 1.13 mmB-L: 1.39 mm
Landmarks
- Cingulum as inferior boundary of access
- Lingual fossa — natural guide for bur placement
Do Not Invade
- Incisal edge (preserve for esthetics and function)
- Labial wall (esthetic zone — maintain dentin thickness)
Canal Anatomy
Configurations
Single canal (Vertucci Type I)80-85%
Two canals merging (Vertucci Type II, 2-1)10-12%
One-two-one (Vertucci Type III, 1-2-1)3-5%
Two separate canals (Type IV) or other<3%
Canal Positions
MCMain Canal
Ovoid/elliptical cervically, round at mid-root and apex; may bifurcate in middle third
BBuccal Canal
When 2 canals present (Type II/III/IV)
PPalatal Canal
When 2 canals present, often narrower
Danger Zones
- ⚠Distopalatal root curvature in apical third — risk of ledging, transportation, or separation
- ⚠Labial perforation if access directed too far labially
- ⚠Thin root dentin in mid-root — strip perforation risk with aggressive filing
Clinical Tips
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Warning
Distopalatal curvature in apical third in ~58% of teeth — pre-curve files and use flexible NiTi
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Warning
Check for dens invaginatus on radiograph before access — most common in this tooth (0.25-10%)
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Technique
If file appears off-center on radiograph, suspect bifurcation — take angled radiograph (SLOB rule)
Anatomical Variations
Dens Invaginatus (Dens-in-dente)
0.25-10% (most common in lateral incisors)Invagination of enamel organ into tooth structure. Oehlers Type I: confined to crown (most common). Type II: extends past CEJ into root. Type III: communicates with periodontal ligament or apical foramen.
Access Modification: Type I: modified access to debride invagination. Type II/III: may require combined endodontic-surgical approach or intentional replantation
Two Roots / Two Separate Canals
<3% (rare, documented case reports)Bifurcation of root in middle or apical third with two separate canals and foramina. May have labial and palatal roots.
Access Modification: Extended labiopalatal access to locate both orifices; CBCT for mapping
Peg-shaped Lateral Incisor
~2.8%Conical, undersized crown with simplified root canal anatomy. Usually single small canal.
Access Modification: Smaller access cavity; conservative preparation due to reduced dentin thickness