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Various techniques may be used, either alone or in combination, to preserve or improve the

denture-bearing area. There are three broad categories of preprosthetic surgery procedure:

1. Soft-tissue surgery

2. Bone-contouring (or augmentation) procedures 3. Endosseous implant surgery.

Some of the procedures described below may be included in more than one category.

Soft-tissue procedures Excision of hyperplastic tissue

Hyperplastic oral mucosa under or adjacent to a removable denture usually arises in response to chron-ic irritation, for example, from an over-extended den-ture fl ange or a defi ciency in the fi tting surface of a denture, trauma from a sharp cusp on an acrylic tooth or an ill-fi tting denture clasp. Poor denture design may also cause mucosal hyperplasia (Figs 11.5, 11.6).

Surgery may be unnecessary if the cause of the hyperplastic tissue is identifi ed and eliminated; the hyperplastic tissue will then usually diminish in size or resolve completely. Any residual tissue that inter-feres with denture construction can be removed via an elliptical incision as for an excision biopsy (see Ch. 8, p. 109). Where possible (e.g. in the buccal sulcus or on the cheek), the incision may be closed by suturing the wound edges together (primary closure).

On the edentulous ridge, the periosteum is elevated to undermine the edges of the wound, and the edges of the mucoperiosteal fl aps can then be advanced to achieve wound closure. A split-thickness skin graft may be required to cover extensive areas of denuded oral mucosa. A keratinized-free mucosal graft may be harvested from the hard palate for smaller areas.

Summary of treatment planning

● Consider the patient’s concerns and expectations

● Assess their medical fi tness

● Examine both extraorally and intraorally

● Assess the height, width, regularity and relationship of the ridges

● Consider whether improvement can be achieved by prosthetic means

● Radiographs may be needed to exclude other pathology and to determine the quantity and quality of bone

● Study casts and a diagnostic wax-up may be of value PREPROSTHETIC SURGERY PROCEDURES

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It is often benefi cial to place a temporary soft lining in the existing denture after surgery, to minimize the likelihood of further irritation, prior to remaking the prosthesis.

Prominent labial fraenum

The fl ange of a denture may traumatize a prominent labial fraenum or muscle attachment (Fig. 11.3). If the fraenum is relatively small, this may be managed by trimming back the labial or lingual denture fl ange.

However, the denture may be weakened and it might fracture if extensive trimming is undertaken to relieve the fraenum. Excision of the fraenum (fraenectomy) may be indicated to avoid this.

For the fraenectomy procedure (also described in Ch. 12) vertical incisions are made parallel to the fraenum, extending into the sulcus from the residual ridge to form a rhomboid-shaped wound (Fig. 11.7). The incisions are widest at the base of the labial sulcus. The insertion of the fraenum into the alveolar ridge is held with either a suture or a pair of toothed tissue forceps and the fraenum is dissected, leaving periosteum covering the surface of the bone. Interrupted sutures are inserted through the mucoperiosteal fl ap to achieve wound closure.

A modifi cation of this procedure incorporates a Z-plasty, to preserve sulcus depth (Fig. 11.8). However, the Z-plasty can be technically more diffi cult than the fraenectomy technique described above.

Fibrous enlargement of the maxillary tuberosity Ideally, the maxillary tuberosities are fi rm for denture support. If they are fl abby and mobile, the soft tissues of the tuberosities may displace during impression-taking for a new denture, making denture construc-tion diffi cult. Fibrous enlargement of a maxillary tuberosity may be reduced (Fig. 11.9) by making two incisions along the crest of the alveolar ridge to form an ellipse, angled towards the centre of the Fig. 11.5 This is an extensive ‘leaf fi broma’ of the hard palate.

The lesion was attached to the hard palate by a small stalk (a peduncle) and resembled the outline of a relief chamber incorporated into the fi tting surface of the denture.

Fig. 11.6 Fibroepithelial hyperplasia associated with the irritant margin of an ill-fi tting lower denture.

Lip

Alveolus Fraenum (a)

(b)

Fig. 11.7 Conventional fraenectomy.

(a, b) With the upper lip everted, a rhomboid-shaped incision is made around the fl eshy fraenum, extending through the oral mucosa to the

submucosal layer below, preserving muscle fi bres of orbicularis oris.

151 151 ridge down to bone. A triangular-shaped wedge of tissue is excised, and a ‘fi llet’ of soft tissue is excised from each fl ap. The wound edges are then sutured together.

Hard-tissue procedures Dentoalveolar procedures

Care is taken when extracting teeth or dental roots with forceps or via a surgical approach to ensure preservation of alveolar bone and oral mucosa.

Buccal bone may fracture and remain adherent to a tooth root after extraction. This is most likely to occur with canine teeth if there has been minimal bone loss through periodontal disease. Use of a dental elevator will minimize the risk of fracture of alveolar bone before delivery of a tooth with extraction for-ceps. Fracture of the maxillary tuberosity during tooth extraction may result in extensive bone loss leading to poor denture stability.

The periotome (Fig. 11.10) is increasingly being used to extract teeth before implant surgery (cf.

extraction instruments described in Ch. 4). This device is composed of a narrow, fl at blade which is pushed down into the gingivae, and breaks down the periodontal fi bres supporting the tooth. Periotomes preserve the alveolar bone, which is essential when placing an immediate endosseous implant after tooth (a)

(b)

(c)

Fig. 11.8 ‘Z-plasty’ fraenectomy.

(a) After the fl eshy fraenum has been excised, two oblique incisions are made down to periosteum.

(b) The triangular-shaped fl aps are raised to expose underlying bone and the fl aps are reversed so that the inferior triangular fl ap now becomes the most superior.

(c) The wound is closed.

(b) (c)

(a) (d)

Fig. 11.9 Reduction of hyperplastic tuberosities.

(a) An elliptical incision is made down to bone and the ellipse of soft tissue is excised.

(b) The scalpel creates an oblique cut, as seen in cross-section.

(c) The underlying submucosa is fi lleted to reduce the bulk of the tuberosity.

(d) The wound edges are apposed and sutured.

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extraction (web sites include http://www.citagenix.

com, http://www.klsmartinusa.com/Offi ceProducts/

periotome.htm).

If alveolar bone is displaced during tooth extrac-tion, it is repositioned by digital pressure after tooth delivery. Loose fragments of alveolar bone in the

socket are removed to prevent delayed healing. Larger fragments with an intact periosteal blood supply are left in situ.

Alveoplasty

This procedure is performed to recontour an uneven alveolar ridge. Alveoplasty is undertaken either at the time of tooth extraction (primary) or after the alveolar ridge has healed (secondary). Alveoplasty removes the least amount of bone necessary to achieve a smooth bone contour.

Primary alveoplasty involves the exposure of a tooth socket to allow trimming of bone fragments with bone rongeurs or a bur to create a smooth, rounded socket outline. When several adjacent teeth are removed, alveoplasty may be combined with interseptal alveolotomy to eliminate bony undercuts (Fig. 11.11).

After tooth extraction, a bony protuberance may exist on the edentulous ridge or a bony undercut Fig. 11.10 An example of a periotome. The fl at blade inserted

into the handle is interchangeable with other blades. The blade is inserted into the periodontal ligament and through continuous manipulation, the periodontal fi bres are cut around the tooth until it is extracted.

Bone removed Sockets

(a) (b)

(c) (d)

Fig. 11.11 (a) Reduction of an alveolar undercut by removal of the interseptal bone (interseptal alveolotomy). This might be required in the anterior maxilla in a patient with proclined incisor and canine teeth. (b) After extraction, rongeurs (bone nibblers) or bone shears are used to remove the interseptal bone. (c) Using digital pressure the buccal alveolar bone (still attached to the periosteum) is ‘in-fractured’ to reduce the bony undercut. (d) Sutures are placed to close the wound.

153 153 may be present several months later, compromising

denture stability. Secondary alveoplasty is then under-taken. An incision is made along the crest of the ridge to expose the alveolar bone surface. The bony prominence or undercut is smoothed with a bur, bone fi le or a chisel to achieve the desired contour (Fig. 11.12), and after palpating the reshaped ridge to ensure a smooth contour, the wound is closed with sutures.

Excision of a maxillary or mandibular torus A torus (Figs 11.13, 11.14) is a developmental bone exostosis, present typically either on the midline of the hard palate or on the lingual aspect of the mandible above the mylohyoid ridge (usually bilat-erally). Patients are often unaware of their existence.

There are other causes of bony expansion of the jaws, some of which may have a history of slow onset and gradual enlargement. A neoplastic lesion (usually of minor salivary gland origin) sometimes develops on the hard palate, and it has been known for a dentist to ease a denture to accommodate an enlarg-ing malignant growth. If there is doubt about the nature of any lesion, the patient is referred for a specialist opinion.

A denture rubbing on a torus may cause ulceration of the overlying oral mucosa and pain. Removal of a torus may therefore be indicated if the denture cannot be constructed to avoid it.

Radiographs are taken before excision of a maxil-lary torus to examine its structure. If a maxilmaxil-lary torus has an air space within it that communicates with the fl oor of the nose, then excision of the torus might result in an oronasal fi stula, which can be diffi cult to treat.

Limited surgical access or a pronounced gag refl ex might compromise treatment under local anaesthesia.

General anaesthesia is sometimes indicated, parti-cularly for maxillary surgery.

Surgical access to a palatal torus is gained via a midline incision over the lesion, with short (avoiding the greater palatine artery) relieving incisions at either end (Fig. 11.15). The fl aps are raised to expose Fig. 11.12 (a) Reduction of a bony protuberance that is

interfering with denture fi tting. (b) An incision has been made along the crest of the alveolar ridge. A mucoperiosteal fl ap has been raised, and a round surgical bur is used to smooth the protuberance. (c) The wound is debrided and the fl ap is sutured back into position.

(a)

(c)

(b)

Fig. 11.13 Lingual tori are typically bilateral, although the patient is often unaware of their existence.

Fig. 11.14 Torus palatinus is typically symmetrical about the midline of the hard palate.

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the torus, and the mass is excised either with a rotary bur, a chisel or both. Destruction of the torus with a rotary bur (e.g. a large acrylic bur) ensures safe, gradual removal of the mass. Alternatively a fl at fi ssure bur is used to section the torus into smaller pieces, which are freed with a chisel and a surgical mallet. After suturing the fl aps, an acrylic surgical stent (cover plate) may then be placed to cover the wound, to help prevent haematoma formation.

A mandibular torus is exposed by raising a lingual fl ap, releasing the gingival margin around any teeth adjacent to the torus. If the patient is edentulous, the incision is along the crest of the alveolar ridge, avoiding the mental neurovascular bundle (Fig. 11.16).

A surgical bur or chisel and mallet may then be used to divide the torus from the surface of the mandible.

After removal of the excess bone, the osteotomized surface is palpated to ensure a smooth outline before the lingual fl ap is replaced and sutured (a surgical stent may be placed to prevent dead space and haematoma formation).

Restoration of grossly defi cient denture-bearing areas

Many surgical procedures have been devised to aug-ment atrophic jaw bone. A key problem with bone augmentation is the resorption that follows such surgery, leaving the patient without signifi cant gain (a)

(e) (f)

(d) (c)

(b)

Fig. 11.15 Removal of a palatal torus. (a) A midline incision is made across the bony mass, with lateral extensions anteriorly and posteriorly. (b, c) The mucoperiosteal fl aps are refl ected to expose the bony mass. (d) A bur is used to divide the torus into small pieces. (e) A chisel is used to elevate the small fragments of bone from the hard palate. (f) The wound is debrided and the bone is smoothed with a bur, then sutures are placed to close the wound.

155 155 in function. Bone grafting on its own is insuffi cient to

improve a patient’s defi ciency. When undertaken in combination with endosseous implants, the outcome of bone grafting is often highly encouraging.

OSSEOINTEGRATED (ENDOSSEOUS)