Janaphan K, et al. J Periodontal Implant Sci. 2026 Jan;56:e2. https://doi.org/10.5051/jpis.2502400120

Background: Altered passive eruption (APE) is one of the etiological factors associated with excessive gingival display and is commonly treated with esthetic crown lengthening (ECL). However, existing classification systems provide limited guidance for selecting appropriate treatment approaches. Objectives: The aim of this study was to evaluate (1) the expected outcome of ECL in eliminating unattractive excessive gingival display (4 mm) based on digital smile assessment and (2) the distribution of teeth and patients according to the modified APE classification. Methods: Forty-two Thai patients with APE underwent clinical examination, digital smile assessment, intraoral scanning, and CBCT. Predicted gingival display (PGD) was calculated to assess the expected outcomes of ECL. The modified APE classification, incorporating CEJ–BC distance and buccal bone thickness, was analyzed at both the tooth and patient levels. Results: A total of 252 maxillary anterior teeth were assessed. Most patients (78.57%) presented with APE and hyperactive upper lip. The mean gingival display (GD) was 6.04 ± 1.76 mm, with GD ≥ 4 mm observed in 92.86% of patients. The mean PGD was 3.56 ± 1.71 mm, and ECL was predicted to reduce GD to < 4 mm in 66.67% of patients. Teeth were classified as Class I (28.97%), II (15.48%), III (41.27%), and IV (14.28%); only Types II (11.9%) and III (88.1%) occurred at the patient level. Conclusions: ECL performed at the CEJ level is predicted to eliminate excessive gingival display in approximately two-thirds of APE patients. The modified APE classification offers guidance for selecting surgical approaches, highlighting the necessity of open-flap procedures and the limited applicability of flapless approaches.

Several studies have suggested that peri-implant keratinized mucosa (PIKM) is related to peri-implant health. Thus, PIKM augmentation, such as free gingival grafting (FGG), is often performed to re-establish the keratinized tissue zone. Implant sites may influence the long-term stability of the re-established PIKM; however, relevant data are insufficient. In three patients, three implants were placed in areas with missing first and second mandibular molars. To create the PIKM zone, an FGG was used. During the follow-up (≥20 years), the re-established PIKM at the distal site in the posterior mandible showed greater reduction than at the mesial site, indicating site-specific stability characteristics. Some implants present with unfavorable bone remodeling and peri-implant diseases, and these conditions seem to contribute to PIKM stability by forming unattached parts of the PIKM. The findings of this study should be verified in a larger patient population with healthier conditions.