Crown Lengthening For Type 1B Altered Passive Eruption

This case report highlights the efficacy of surgical crown lengthening in managing Type 1B altered passive eruption (APE), a condition characterized by gummy smile and short clinical crowns, leading to compromised aesthetics and functional challenges. A 32-year-old female presented with gingival swelling and a "gummy smile" .Clinical examination revealed short clinical crowns in the maxillary teeth 14-23, with hypertrophic gingival margins located coronally to the cementoenamel junction (CEJ). CT scans demonstrated thickened labial bone plates in the maxillary teeth. The bone crest of teeth 14-23 was close to the cementoenamel junction, with distances generally <2 mm. A diagnosis of APE (Type I, Subtype B) was established. Under the guidance of the crown proportion gauge(HuFriedy), surgical crown lengthening was performed, involving precise positioning of the gingival margin, bone recontouring and subepithelial connective tissue suturing. Postoperative healing was uneventful, and at 3-month follow-up, the patient demonstrated harmonious gingival architecture, improved tooth proportions, and enhanced smile aesthetics. This case highlights the significance of application of crown proportion gauge in precisely controlling bone reduction and gingival margin positioning during surgery, particularly when widespread bony protrusions prevent proper seating of surgical guides. Additionally, the case employed subepithelial connective tissue suturing, which not only enhanced aesthetic outcomes postoperatively but also contributed to improved healing and reduced postoperative scarring. The application of crown proportion gauge and the use of minimally invasive aesthetic suturing techniques are essential for the successful execution of crown lengthening surgery and ensuring favorable postoperative outcomes.