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Permanent Maxillary Right Lateral Incisor

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Dental Anatomy Dental Glossary

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Permanent Maxillary Right Lateral Incisor

The permanent maxillary right lateral incisor is the second tooth from the midline in the upper right quadrant of the mouth, positioned between the maxillary right central incisor and the maxillary right canine. Designated tooth #7 in the Universal Numbering System and UR2 in the FDI two-digit notation, it typically erupts between ages 8 and 9 as part of the permanent dentition.

Anatomy and Structure

The crown is noticeably smaller and slightly shorter than the adjacent central incisor, with a rounded mesioincisal angle and a more distinctly curved distoincisal angle. The lingual surface features a well-defined cingulum, pronounced marginal ridges, and a lingual fossa whose depth varies considerably — a deeper fossa increases susceptibility to caries. A single root, typically straight or mildly distally inclined, supports the crown and is proportionally long relative to crown height. The outer enamel layer is thinner at the incisal edge, and the underlying dentin core is proportionally larger than in the central incisor.

Clinical Significance

This tooth contributes to anterior guidance, assists in phonation — particularly fricative sounds — and defines the visual transition between the incisors and the canine eminence. Clinicians should be alert to several common developmental variations:

  • Peg lateral incisor: A microdont form with a conical, tapered crown, occurring in roughly 2% of the population.
  • Congenital absence (hypodontia): The maxillary lateral incisor is the second most commonly missing permanent tooth after the third molar.
  • Dens invaginatus (dens in dente): An invagination of enamel into the pulp space that predisposes the tooth to early pulp pathology.
  • Palatogingival groove: A developmental groove on the lingual or root surface that compromises the periodontal ligament attachment and can serve as a pathway for infection.
  • Root dilaceration: An abrupt angulation of the root, often resulting from trauma to the primary predecessor during root development.

Restorative and Orthodontic Considerations

When a peg lateral or congenitally absent lateral incisor is present, treatment planning typically requires coordination between restorative dentistry and orthodontics. Options range from composite resin recontouring and porcelain veneers to single-unit implant crowns placed after skeletal growth is complete. Space management is critical: without guidance, the canine can drift mesially and substitute for the lateral — a planned outcome in some cases but an esthetic liability if unaddressed. Thorough periapical radiographic assessment and careful occlusal analysis are essential before committing to any restorative pathway.

Identifying the normal anatomy and common anomalies of the permanent maxillary right lateral incisor early gives clinicians the opportunity to intercept developing problems and preserve both function and esthetic harmony across the anterior dentition.