Residency · Residency · Oral Maxillofacial Surgery
Pre-Prosthetic Surgery and Alveolar Ridge Management
Overview
Pre-prosthetic surgery encompasses procedures that prepare the oral hard and soft tissues for optimal prosthetic rehabilitation. The goals are to create adequate bone volume, eliminate soft tissue interferences, establish proper ridge form, and ensure a stable prosthetic foundation. These procedures are increasingly relevant in the context of implant-supported prostheses in addition to conventional removable prosthetics.
Hard Tissue Procedures
Alveolar Ridge Recontouring (Alveoloplasty)
Alveoloplasty involves smoothing irregular alveolar bone following extractions. It can be performed at the time of extraction or as a secondary procedure. The technique requires reflecting a mucoperiosteal flap, removing sharp bony prominences with a rongeur or rotary instrument, smoothing with a bone file, irrigating, and closing primarily. Excessive bone removal should be avoided, as it compromises ridge height for future implant placement. The intraseptal alveoloplasty (Dean technique) compresses interseptal bone to reduce ridge height while preserving the labial and buccal plates.
Torus Removal
Torus Palatinus
Torus palatinus is a benign exostosis of the midline hard palate. Indications for removal include interference with prosthesis fabrication, recurrent ulceration, patient concern, and the need for palatal donor graft tissue. The technique involves a midline palatal incision (using a lazy-S or Y-incision to avoid scar contracture over the midline prominence), bilateral mucoperiosteal flap reflection, sectioning the torus with a bur or piezosurgery, removal in segments, smoothing the base with rotary instruments, and primary closure. Complications include palatal perforation (especially when the underlying bone is thin), excessive bleeding from the greater palatine vessels, and wound dehiscence.
Torus Mandibularis
Torus mandibularis consists of bilateral exostoses on the lingual aspect of the mandible in the premolar region. Indications include prosthetic interference, speech difficulty, and recurrent trauma or ulceration. The technique involves a crestal or sulcular incision with an anterior releasing incision, lingual mucoperiosteal flap reflection (with care to protect the lingual nerve), removal with chisel, rongeur, or rotary instrument, smoothing, and closure. Complications include lingual nerve injury from retraction, floor of mouth swelling, and hematoma.
Exostosis Removal
Buccal exostoses are common on the maxillary buccal cortex. The surgical approach is similar to torus removal, involving mucoperiosteal flap reflection, bone removal, and closure. While less commonly indicated than tori removal, buccal exostoses may interfere with prosthetics or implant planning.
Genial Tubercle Reduction
Enlarged genial tubercles may interfere with the lower denture flange. Reduction is performed with rotary instruments, with care to avoid excessive reduction that would detach the genioglossus and geniohyoid muscles from their attachments.
Mylohyoid Ridge Reduction
A sharp or prominent mylohyoid ridge causes denture discomfort on the lingual aspect. Smoothing with a bone file or rotary instruments is performed through a lingual mucoperiosteal flap.
Maxillary Tuberosity Reduction
Enlarged or fibrous tuberosities may limit the interarch space available for a prosthesis. A bony tuberosity requires flap elevation and bone reduction with a rongeur, piezosurgery, or rotary instruments, with care taken to avoid creating an oroantral communication. A fibrous tuberosity is managed with elliptical excision of excess soft tissue and primary closure. Proximity of the maxillary sinus should always be checked before bone reduction.
<image>Surgical illustrations showing the technique for torus palatinus removal, including the midline palatal incision design, sectioning of the torus with a bur, removal of segments, and primary closure</image>
Soft Tissue Procedures
Vestibuloplasty
Vestibuloplasty deepens the vestibular sulcus to increase the denture-bearing area and retention. It is indicated when ridge resorption has resulted in a shallow vestibule with muscle and frenum attachments near the crest. Several techniques exist. The submucosal vestibuloplasty (Obwegeser-type) uses supraperiosteal dissection to reposition muscle attachments. The transpositional flap vestibuloplasty (Kazanjian) transposes a labial mucosal flap to the vestibular depth while leaving the periosteum exposed to granulate. The Clark technique involves periosteal fenestration with the lip mucosa sutured to the periosteum at the new depth. Split-thickness skin graft vestibuloplasty places a skin graft over denuded periosteum, stented in place. Free mucosal graft vestibuloplasty grafts palatal mucosa to the vestibular depth. Complications include relapse (the most common, with up to 50% depth loss), graft contracture, paresthesia, and scarring.
Frenectomy
Frenectomy involves removal or repositioning of aberrant frenal attachments. Labial frenectomy addresses a high frenal attachment causing denture dislodgement or contributing to a diastema. Lingual frenectomy treats ankyloglossia affecting tongue mobility, though this is a less common pre-prosthetic indication. Techniques include simple excision, Z-plasty, V-Y plasty, and laser excision. Laser frenectomy offers reduced bleeding and postoperative discomfort.
Epulis Fissuratum Excision
Epulis fissuratum consists of hyperplastic tissue folds caused by chronic irritation from ill-fitting denture flanges. The redundant tissue is excised with scalpel, electrocautery, or laser. The denture must be refit or replaced to prevent recurrence, and tissue should be submitted for histopathologic examination to rule out dysplasia or malignancy.
Papillary Hyperplasia Treatment
Inflammatory papillary hyperplasia of the palatal vault is associated with ill-fitting dentures and poor hygiene, especially in Candida-colonized patients. Conservative management involves removing the denture for an extended period, antifungal therapy with nystatin, and placing a tissue conditioner in the denture. Surgical management involves superficial excision with electrosurgery, laser ablation, or mucosal stripping, with the wound healing by secondary intention. A new denture is fabricated after healing.
Inflammatory Fibrous Hyperplasia (Flabby Ridge)
Excessive mobile fibrous tissue replacing alveolar bone is most common in the anterior maxilla and causes denture instability. Management involves excision of the fibrous tissue down to bone, with consideration of onlay bone grafting if the bone deficiency is significant.
Ridge Augmentation for Prosthetic Rehabilitation
Autogenous Bone Grafting
Onlay grafting augments deficient ridges using bone harvested from donor sites including the mandibular symphysis, ramus, iliac crest, tibia, or calvarium. It is indicated for severe resorption that precludes implant placement.
Hydroxyapatite Ridge Augmentation
This historical technique involved subperiosteal placement of hydroxyapatite granules to augment ridge form. It has been largely replaced by implant-based prosthetic rehabilitation due to complications including particle migration, infection, and mucosal breakdown.
Subperiosteal Implants
Subperiosteal implants are custom-fabricated frameworks placed over the alveolar ridge beneath the periosteum. They were historically used for severely atrophic mandibles or maxillae but have been largely supplanted by endosseous and zygomatic implants. There is renewed interest in this concept with the advent of 3D-printed patient-specific subperiosteal implants.
<image>Clinical photographs showing common pre-prosthetic surgical conditions requiring intervention: epulis fissuratum from ill-fitting denture, torus mandibularis, and papillary hyperplasia of the palate, with corresponding post-surgical results</image>
Management of the Atrophic Mandible
Cawood and Howell Classification
The Cawood and Howell classification describes progressive ridge resorption. Class I is dentate. Class II is immediately post-extraction. Class III has adequate ridge height and width with a rounded form. Class IV is a knife-edge ridge with adequate height but inadequate width. Class V is a flat ridge with inadequate height and width. Class VI is a depressed ridge with loss of basal bone.
| Class | Description |
|---|---|
| I | Dentate |
| II | Immediately post-extraction |
| III | Adequate height and width, rounded form |
| IV | Knife-edge ridge: adequate height, inadequate width |
| V | Flat ridge: inadequate height and width |
| VI | Depressed ridge with loss of basal bone |
Considerations
The severely atrophic mandible (Class V-VI) presents challenges for both conventional and implant prosthetics. There is a risk of pathologic fracture with severe atrophy, and the mental nerve may be at or near the crest of the ridge. Options include bone grafting (onlay or interpositional), distraction osteogenesis, short or narrow implants, and subperiosteal implants.
Management of the Atrophic Maxilla
In the posterior maxilla, sinus pneumatization reduces available bone and sinus augmentation is required. In the anterior maxilla, labial bone resorption may necessitate onlay grafting or guided bone regeneration. For severe atrophy, options include zygomatic implants, Le Fort I osteotomy with interpositional grafting, or full arch bone grafting. The tuberosity region may offer adequate bone when other sites are deficient.
Clinical Pearls
Pre-prosthetic surgery should always be performed with the end prosthetic goal in mind, in coordination with the restorative dentist or prosthodontist. Over-reducing alveolar bone during alveoloplasty should be avoided because future implant placement may be compromised. When removing tori, sectioning into multiple pieces rather than attempting en bloc removal reduces the risk of fracture propagation and palatal perforation. Vestibuloplasty outcomes are improved when combined with skin or mucosal grafting to reduce relapse. Piezosurgery is advantageous for torus removal and alveoloplasty, offering precise cuts with reduced soft tissue trauma. In edentulous patients with mandibular atrophy, the mental nerve position should be confirmed radiographically before any surgical intervention.
References
- Peterson LJ, et al. Contemporary Oral and Maxillofacial Surgery. 7th ed. Elsevier. 2019.
- Cawood JI, Howell RA. A classification of the edentulous jaws. Int J Oral Maxillofac Surg. 1988.
- Obwegeser HL. Surgical correction of small or retrodisplaced maxillae: the "dish-face" deformity. Plast Reconstr Surg. 1969.
- Hillerup S. Preprosthetic surgery in the elderly. J Prosthet Dent. 1994.
- Stoelinga PJ, et al. The use of autogenous bone grafts in preprosthetic surgery. J Oral Maxillofac Surg. 2000.
