Vestibuloplasty all are true except:
Mucosal advancement
Use of hydroxyapatite
Secondary epithelialization
Usage of epithelial grafts
Vestibuloplasty
The reduction of alveolar ridge size is frequently accompanied by an apparent encroachment of muscle attachments on the crest of the ridge. These so-called high (mandibular) or low (maxillary) attachments serve to reduce the available denture-bearing area and to undermine denture stability. 
Key concept:
Vestibuloplasty is a soft tissue procedure, and does not necessitate bone grafts.
TYPES OF VESTIBULOPLASTY:-

Mucosal advancement (Submucous) V’plasty:

The mucous membrane of the vestibule is undermined and advanced to line both sides of the extended vestibule.


Secondary epithelization vestibuloplasty:

The mucosa of the vestibule is used to line one side of the extended vestibule, and the other side heals by growing a new epithelial surface.


Grafting vestibuloplasty:

Skin, mucous membrane and dermis can be used as a free graft to line one or both sides of the extended vestibule.