An in vivo study to correlate the relationship of the extraoral and intraoral anatomical landmarks with the occlusal plane in dentulous subjects.

ABSTRACT

Background: The occlusal plane position is considered to be the primary link between esthetic and function. Aim: To evaluate the relationship between extraoral and intraoral soft tissue landmarks with the occlusal plane in dentulous subjects on both sides and to check for any variations. Study and Design: An in vivo study and 100 subjects with all healthy permanent teeth in normal arch and alignment were selected from Modern Dental College and Research Centre, Indore. Materials and Methods: Three custom made instruments (occlusal plane analyzer, buccinator groove relator, and level analyzer) were indigenously designed to check parallelism of the interpupillary line, ala‑tragus line, buccinator groove with the occlusal plane. Relation of retromolar pad with the occlusal plane was checked with the metallic scale. Statistical Analysis: Chi‑square test. Results: In 20.0% subjects, the occlusal plane was parallel to the interpupillary line. The posterior reference point for ala‑tragus line was middle point on right side in 56% and left side in 58% subjects. Intraorally, right side 59% and left side 62% subjects had the occlusal plane at the same level as that of buccinator groove. Right side 48% and left side 45% subjects showed occlusal plane at the middle one‑third of retromolar pad. Conclusion: The occlusal plane is not generally parallel to interpupillary line. The occlusal plane is parallel to the ala‑tragus line with middle point of tragus as posterior reference point on right and left sides. Both sides, the buccinator groove and the middle one‑third retromolar pad are coinciding with occlusal plane level.