Spontaneous regeneration of keratinized tissue at implants and teeth
Jean‐Claude Imber, Andrea Roccuzzo, Alexandra Stähli, Dieter D. Bosshardt, Fernando Muñóz, Christoph A. Ramseier, Niklaus P. Lang, Anton Sculean
Abstract
Abstract Aim To investigate the spontaneous regeneration of the implanto‐mucosal and dento‐gingival unit after complete removal of keratinized tissue (KT). Materials and Methods One hemi‐mandible per dog ( n = 4) was allocated to receive three dental implants (test sites, premolar region), whereas three premolars on the contralateral side were controls. After osseointegration, the entire KT (buccal + lingual) was surgically excised on all test and control sites, leaving the bone exposed. Clinical measurements were performed before excision (T 0 ) and after 12 weeks (T 1 ). Following healing, the animals were euthanized, and the specimens were histologically processed. Descriptive statistical analyses were performed. Results Clinical measurements revealed that at T 1 , on all teeth, a band of KT was spontaneously regenerated (mean width: 2.60 ± 0.66 mm), whereas on implants, KT was detected only occasionally at mesial or distal but not at buccal sites (mean total: 0.35 ± 0.53 mm; p < .0001). Histologically, spontaneous regeneration of the dento‐gingival unit was evident, displaying masticatory mucosa. At the implant sites, on the other hand, the implanto‐mucosal unit was characterized by a non‐keratinized epithelium and elastic fibres, indicating the characteristics encountered in alveolar mucosa. Conclusion After excision of KT at implant sites, the spontaneous regeneration of the soft tissue is characterized by a non‐keratinized epithelium typical for alveolar mucosa, while at tooth sites the spontaneous regeneration was characterized by soft tissue resembling gingiva.