#Education 01. Sep 2025

Early buccal bone resorption in areas with or without keratinized tissue and different mucosal thickness at implants in healed sites: an experimental animal study

By Antonio Liñares, Hong Jin Tan, Fernando Muñoz, Dragana Rakasevic, Yago Leira, Juan Blanco. A selected scientific recommendation by Dr. Marcin Maj.

STUDY OBJECTIVES AND METHODS

The purpose of this study was to evaluate early buccal bone resorption (BBR) in areas with or without buccal keratinized tissue (KT), and different mucosal thickness (MT) following implant placement at healed sites. In 9 beagle dogs, three months following the hemimaxilla third and fourth premolars extraction, full-thickness flaps were elevated and two tissue-level implants were inserted. Before suturing, each dog was randomly assigned into 3 groups (control, non-keratinized tissue, NKT and non-keratinized tissue plus connective tissue graft, NKT-CTG). In both experimental groups (NKT and NKT-CTG), buccal KT was excised. In the NKT-CTG group, a CTG was sutured to the buccal alveolar mucosa flap (BF) and coronally repositioned around the implant neck, while in the NKT group, only the BF was repositioned. BF with a 2 mm KT band was repositioned around the implants in the control group. Buccal bone thickness (BBT), MT and KT width were measured clinically at baseline. Three months later, BBR and MT were analysed histologically.

RESULTS

  • Mucosal thickness at surgery was similar in NKT and control groups (1.33 ± 0.26 mm and 1.67 ± 0.52 mm, respectively).
  • In the NKT-CTG group, MT was 2.50 ± 0.45. The mean BBT measured at the mid-buccal region was about 1 mm in the 3 groups.
  • Three months later, early BBR was observed in all groups, with mean values of 0.91 mm ± 0.62 (control), 1.11 mm ± 0.69 (NKT) and 1.10 mm ± 0.58 (NKT-CTG).
  • The mean values of MT at a 1.5 mm distance from the marginal mucosa were 1.20 mm ± 0.69 (control), 2.18 mm ± 0.53 (NKT) and 3.45 mm ± 1.33 (NKT-CTG).


CONCLUSIONS

Within the limitations of the present investigation, the presence or absence of KT did not affect early BBR. CTG placed in the zones without KT did not prevent early BBR.

Adapted from A Liñares et al., J Clin Periodontol. 2025 Jun;52(6):920-928, for more info about this publication, click HERE.

This review is part of the Straumann "Scientific Highlights Newsletter 4/25".

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