GOODMORNING Introduction Preprosthetic surgery – is carried out to reform or redesign the soft/hard tissues, by eliminating the biological hindrances to receive a comfortable and stable prosthesis and to create an oral environment to support a functional prosthetic appliance. Pathophysiology of edentulous bone loss Causes – Physiologic, environmental, pathologic or combination of any of the above Patterns of bone loss Most of the bone loss occurs during the first year of the denture wearing It is 10 times greater in the first year than that seen in the following years Bone loss in mandible 4 times greater than in maxilla Resorption in maxilla – on buccal and inferior portion of the alveolar ridge--- resulting in reduced width of maxilla Mandible – resorbs downwards and outwards causing rapid flattening of the ridge. Average bone loss – 1mm per year Aims of preprosthetic surgery To provide adequate support for the placement of RPD/CD To provide adequate soft tissue support/vestibular depth Elimination of pre existing bony deformities eg: tori, prominent mylohyoid ridge etc Correction of maxillary and mandibular ridge relations Elimination of pre existing soft tissue deformities eg: epulis, flabby ridges etc Relocation of frenal or muscle attachments Relocation of the mental nerve Establishment of the correct vestibular depth Treatment Planning Conventional dentures: 1. History taking and physical examination including radiographs 2. Facial esthetic examination– for unsupported upper lip, poor vermillion show, poor/obtuse nasolabial angle, loss of nasolabial forld etc 3. Intraoral examination– Ridge form and contour, quality and quantity of the overlying tissues, frenal and muscle attachments, presence /absence of bony or soft tissue pathologies and relationship of maxillary ridge to mandibular ridge Preprosthetic surgical procedures Alveolar ridge correction Bony surgeries 1. Compression alveoplasty 2. Simple Alveoplasty 3. Labial/ buccal cortical alveoplasty 4. Reduction of Tori and exostoses Soft tissue surgeries Ridge extension procedures/Vestibuloplasty Augmentation Alveoplasty Alveoplasty: Recontouring of the alveolar process Alveolectomy: The excision of a portion of the alveolar process Objectives and principles of alveoplasty Immediate goal in performing an alveoplasty is to provide optimal ridge contour quickly, this should be counterbalanced with ultimate goal of preserving as much bone as possible for continued denture stability Alveolar ridges should be left as broad as possible for maximum distribution of the masticatory load All undercuts especially the opposing ones should be removed Sharp edges should be rounded and gross irregularities should be reduced Mucosa covering the ridge should be uniform in thickness The younger the patient less amount of the bone should be removed during alveoplasty Types of alveoplasty Compression alveoplasty: a. Easiest and quickest b. Compression of outer and inner cortical plates between the fingers c. Done after extractions d. Compression reduces the width of the socket and many otherwise troublesome bony undercuts Simple alveoplasty: a) Usually used to reduce sharp buccal or labial cortical and occasionally lingual or palatal cortical margins. b) Usually an envelop flap is used c) With a rongeur or bone cutting forceps held parallel to the bone margin of the alveolar bone, just the right amount of bone can be removed Labial or buccal cortical alveoplasty: a) Incision made in the gingiva and full thickness mucoperiosteal flap elevated b) A sharp side cutting/Blumenthal forceps is held with one beak beneath the bony rim of the socket and other on the crest of the ridge. c) Small bits of the bone can thus be “bitten off” d) A bony file can be used to smoothen and perfect the contour. This type of alveoplasty is most commonly performed after the tooth removal Labial / Buccal cortical alveoplasty A. Pre op B. After removal of teeth the labial gingiva is elevated C. Rongeur is used to reduce the bone D. Condition after bone trim E. Suturing Dean’s intraseptal(intercortical) alveoplasty: a) After extraction of the teeth , the interradicular bony septa should be removed with a rongeur forceps. b) Dean used a chisel to make an inverted ‘V’ shaped excision of the bone in the labial cortex of the cuspid socket, thus three sides of the labial cortical flap are freed c) Finger pressure is then applied to reduce the labial cortical plate d) This plate recieves its blood supply from the overylying periosteum Dean’s Intraseptal alveoplasty A. For cases with moderate inclination of the teeth B. After removal of teeth, gingival papillae are removed C. Bone bur is used to remove the interradicular medullary bone D. Bone cut is made in the labial cortex at the distolabial aspect of each cuspid socket E. Broad, flat instruments are inserted into the bone trough and outward force is used to fracture the labial cortex F. Finger pressure is used to compress the socket G. Suturing Obwegeser’s technique: a) He suggested further modification of Dean’s technique for extreme maxillary protrusion cases b) He fractured both labial and palatal cortical plates as follows- 1. The teeth are removed as usual 2. The sockets are connected, and rongeurs or burs are used to remove the medullary interradicular bone 3. With a bur the sockets and their interconnections trough id then enlarged. 4. Both labial and palatal plates are cut with burs in the cuspid area to weaken the bone and to form three sided bone flaps in both cortical plates 5. Palatal cortex usually needs to be scored 6. A pair of broad flat elevators are inserted into the sockets and the labial plate is fractured labially and the palatal plate palatally. Finger pressure is then used to mould the alveolar process into the desired shape. Sutures close the gingiva on the socket. 7. A Denture on splint is used to stabilize the fractures alveolar process which heals in 4 to 6 weeks. Obwegeser’s technique A. For cases with extreme labial protrusion B. A broad trough is created with a bone bur connecting all the sockets C. The labial and palatal sockets are cut with a bur D. Palatal cortex is partially cut E. Labial and palatal cortices fractured F. Finger pressure used to compress and mould the socket G. Suturing Reduction of mylohyoid ridge and lingual alveolar crest Alveolar atrophy sometimes accentuates the mylohyoid ridge, which can be plapated through the lingual surface of the mandible Mylohyoid ridge should be reduced whenever the ridge is found to be at level or higher than the alveolar process Sometimes the overlying mucosa becomes traumatized, ulcerates and fails to heal. In such cases the bony edges should be removed to permit the closure of the ulcerated tissues with sutures Technique Incision is made in the residual gingiva on the alveolar crest of the alveolar process in the molar region. Lingual mucoperiosteum is reflected carefully, exposing the mylohyoid ridge and the muscle. The mylohyoid muscle is attached to the edge and inferior surface of the mylohyoid ridge and must be incised with a scalpel Once the muscle has been reflected, the bony edge can be reduced with a chisel or rongeurs and bony file. The detaches muscle will then reattach at a lower level Reduction of Tori and Exostoses Torus palatinus It is a benign, slowly growing, bony projection of the palatine processes of the maxillae and occasionally the horizontal plates of the palatine bones. It occurs bilaterally along the medial suture on oral surface of the hard palate. Slow growing Females > males Etiology - Unknown Palatal tori removal is indicated when: 1. They become so large that they interfere with the speech 2. The overlying mucosa becomes traumatized, ulcerates and fails to heal because of its poor vascularity 3. The torus interferes with the design and construction of a removable dental prosthesis Technique Local anaesthesia is used to block the right and left anterior palatine nerves and the nasopalatine nerve. Median palatal incision is made in the mucosa the full length of the torus with two short, diverging incisions at the anterior and the posterior ends of the torus, avoiding the vascular foramina. Posteriorly care must be exercised to avoid accidental perforation into the soft palate into the nasal cavity Each flap is reflected with a periosteal elevator and then sutured to the mucosa of the alveolar process to keep it out of the operative field. If the torus is small and pedunculated and the palatal bone is thick then it can be cleaved from the palate with a sharp blow of the mallet. If the torus is thick and broad based then a 703 fissure bur can be used to cut longitudinal and transverse grooves in the torus to desired depth. Once the torus has been grooved, the pieces can be removed using the rongeur forceps or mallet and chisel The stump of the torus can be smoothened with bone files, chisels or large bone burs. Prevention of post operative hematoma formation is very important by use of rubber drain splint or stent Removal of palatal torus A. Pre op B. Right and left mucosal flaps reflected. Dental bur used to cut grooves into the torus C. Sharp chisel used to remove the small pieces of the torus D. A bone bur used to smoothen the stump of the torus E. Suturing COMPLICATIONS: 1. Haemorrhage 2. Hematoma 3. Necrosis and sloughing of the palatal mucosa 4. Perforation of the floor of the nose 5. Fracture of the palate Torus Mandibularis It is an exostosis that usually occurs bilaterally on the median surface of the body and the alveolar process of the mandible Generally located in the canine-premolar region Etiology- unkown Equally occur in both the sexes Technique Area is anaethetised with inferior alveolar and lingual nerve blocks Incision is made on the crest of the alveolar process from molar to incisor region. If bilateral tori are to be removed in the same appointment the mucosa in the incisor region should not be reflected Moucperiosteal flap reflected. Mandibular tori can be easily removed with chisel and mallet. A bur can also be used. A stent is usually not required post op in mandibular tori removal Removal of Torus mandibularis A. Pre op Incision made over the crest of the alveolar ridge from molar to central incisor. Chisel is used to remove the torus C. Bone bur is used to smoothen the stump D. suturing Corrective soft tissue surgery Labial Frenectomy The labial frenum is a band of fibrous connective tissue, covered with mucous membrane that binds the lip to the alveolar process. The upper labial frenum is usually more prominent and fibrous than the lower. When a frenum is attached at or near the crest of the alveolar ridge, it maybe subjected to repeated irritation from a denture flange Technique The lip is elevated, everted and tensed so that the frenum becomes prominent. The purpose of the frenectomy is to eliminate the fibrous part of the frenum and the mucosa should be repositioned to cover the surgical defect. A narrow V shaped incison is made in the mucous membrane around the frenum and is carried to the bone. The apex of the V should correspond to the inferior extent of the frenum. When the frenum is detached from the bone with periosteal elevator, most of the connective tissue fibres retract into the upper lip. The small tag of labial mucosa and any surplus connective tissue can beremoved easily with scissors. The margins of the resultant diamond shaped defect can be undermined and closed with sutures Labial Frenectomy A. Lip is everted and the frenum is tensed B. Narrow V shaped incision is made around the frenum through the mucosa and the periosteum C. Fibres of the frenum are stripped away from the bone D. Small tag of labial mucosa and redundant tissue can be removed with scissors E. Margins of the diamond shaped defect undermined F. Suturing Lingual Frenotomy Ankyloglossia/ tongue tie is usually present in children and is corrected in the childhood itself. Occasionally an adult patient maybe foung to have an untreated hypertrophied lingual frenum Test of lingual Function: Patient is asked to to touch the upper lip with the tip of his tongue. When the patient is unable to do frenectomy is indicated. Technique Bilateral lingual nerve blocks are performed. A traction suture is placed on the tip of the tongue so that the tongue may be elevated and the frenum tensed. A transverse incision was made in the mucous membrene of the frenum midway between the ventral surface of the tongue and sublingual caruncles with sharp scissors. Deeper dissection is performed in the midway to avoid ducts of the submandibular salivary glands. The dissection is continued till the tip of the tongue can be retracted sufficiently to touch the maxillary incisor teeth or alveolar process while the mouth is open. The mucosal flaps are undermined with scissors and closed as a longitudinal linear incision. Lingual Frenotomy A. Pre op. B. Suture is placed through the tip of the tongue to retract the tongue and tense the frenum. Transverse incision made C. Deeper dissection is done D. Margins of the diamond shaped defect undermined Suturing INFLAMMATORY PAPILLARY HYPERPLASIA OF THE PALATE Inflamatory papillary hyperplasia is a painless irreversible disease of the oral mucous membrane It commonly occurs in the hard palate in patients who wear complete maxillary denture Younger patients affected more than older patients Etiology is obscure Number of contributing factors include 1. Poorly fitting denture 2. Wearing a denture 24 hours a day 3. Poor oral hygiene 4. Patients wearing dentures with palatal relief Treatment includes early stages – non-surgical treatment such as proper denture adjustments combined with tissue conditioner If removal is required a mucousal excision superficial to periosteum is recommended Another technique to use is electrosurgical loops After excision patient’s denture or a specially prepared surgical stent can be lined with an analgesic paste and used to cover and protect the surgical site Granulation and reepithelization take 3 - 6 weeks after which new denture can be made Fibrous Hyperplasia of maxillary tuberosity Surgical reduction of hyperplastic submucosa of maxillary tuberosity can be performed under local anaesthesia Elleptical Incisions are made around the gingival masses and are carried to the bone so that full thickness block of tissue can be removed with rongeur forceps Buccal and palatal flaps should be thinned uniformly The incision is then closed with dissolvable sutures Fibrous hyperplasia of maxillary tuberosity Vestibuloplasty Vestibuloplasty is a surgical procedure whereby the oral vestibule is deepened by changing the soft tissue attachments This procedure increases the size of the denture bearing area and height of the residual alveolar ridge Vestibuloplasty procedure can be divided into following categories 1. Mucosal advancement(Submucous) Vestibuloplasty - The mucous membrane of vestibule is undermined and advanced to line both the sides of the extended vestibule 2. Secondary epithelization (Reepithelization)Vestibuloplasty – The mucosa of the vestibule is used to line one side of the extended vestibule and the other side heals by growing new epithelial surface 3. Grafting Vestibularplasty – Skin mucosa and dermis can be used as a free graft to line one or both the sides of the extended vestibule Mucosal Advancement (Submucosal) Vestibuloplasty Primary criterion for this type of procedure is presence of adequate amount of bone and healthy mucosa A test can be performed to determine whether sufficient mucosa is available With lips in a relaxed position mouth mirror is inserted into the vestibule to the depth required prosthetically if the upper lip is not displaced upward or drawn inward it can be assumed that there is sufficient mucosa for the advancement procedure Closed submucous vestibuloplasty Objectives 1. To extend the vestibule to provide the adequate ridge height and 2. To excise or transfer the submucous connective tissue to a position farther from the crest of the ridge to prevent relapse Given by Obwegeser (1959) Technique – Vertical incision is made in the midline of the vestibule through the mucosa only extending from the muco gingival junction into the lip With the lip everted in the horizontal plane a scissior is introduced into the incision and blunt dissection is performed on both the sides A tunnel is formed mucosa and submucosa extending from the mucogingival junction into the lip The tunnel is carried posteriorly to zygomatic buttresses of the maxilla or to mental foramen area of the mandible When the submucous tunnels have been completed the vertical incision is deepened to periosteum at the midline Super periosteal dissection extended as far as the proposed vestibular extention required The freely mobile mucosa then is adopted to the deepened sulcus with fingure pressure Vertical incision is sutured Closed submucous vestibuloplasty A. Median incision made B. Mucous membrane undermined with blunt dissection as dar as zygomaticomaxillry ridge C. Tunnels created on either side with suopraperiosteal dissection D. Connective tissue septum excised E. Suturing Open view submucous vestibuloplasty Given by Wallenius(1963) Similar to Obwegeser technique but used an open view procedure Horizontal incision is made along mucogingival junction through mucosa only The mucosa is dissected from submucosa into the lip Supraperiosteal dissection is then performed to the extent desired for proposed vestibular extention Stay sutures placed in the flap to fix into the periosteum deep in the vestibule Free margin of the flap then is returned to its original position and sutured Secondary epithelialization(reepithelialization) vestibuloplasty It is indicated when sufficient bone is present but the mucosa is either insufficient or of poor quality There are two basic techniques each with several variations Given by Kazanjian(1935) and another by Clark(1953) Kazanjian Technique Incision is made in the mucosa of the lip and a large flap of labial and vestibular mucosa is reflected The vestibule is deepened by supraperiosteal dissection The flap of mucosa is turned downward from its attachment on the alveolar ridge and is placed directly against the periosteum to which it is sutured Rubber catheter stent is placed into the deepened sulcus and fixed with percutaneous sutures Catheters removed after 7 days The labial donor sight is left to granulate and heal by secondary epethelization Kazanjian’s technique Lipswitch Vestibuloplasty Variation of Kazanijian Technique The mucosal flap is developed in the same way as given by Kazanjian with the free margin in the lip and the base attached to the crest of the residual alveolar ridge. But instead of being excised the periosteum is incised and high on the alveolar ridge just below the crest and reflected from the bone The flap consisting of periosteum connective tissue, and muscle, is tranposed outwardly and sutured to the margin of the raw wound in the lip Thus the vestibule is lined on the osseous side with mucosa and on the labial side with periosteum Clark’s technique Incision is made on the alveolar ridge and dissection is carried out to the depth desired Mucosa of the lip is undermined to the vermillion border Sutures are placed in the free margin of the mucosal flap and are tied to the skin over a cotton roll Soft tissue of the vestibule is thus covered with mucosa, whereas, on the osseous side, the raw periosteal surface is left to granulate and epithelialize Clark’s Technique Lingual Sulcoplasty Used in patients with grrossly resorbed mandible Extention of the lingual sulci or the floor of the mouth is lowered to increase the denture bearing area. Anterior lingual sulcoplasty: Suggested by Cooley(1952) Consists of lingual frenotomy and transplantation of the lingual fibres of the genioglossus muscle. It is often combined with reduction of the genial tubercles Posterior lingual sulcoplasty: The floor of the mouth frequently becomes elevated above the level of the residual alveolar ridge during normal functional movements especially the posterior fibres of the residual alveolar ridge. Mylohyoid ridge should be palpated. If the mylohyoid ridge reduction is to be performed , the periosteum should be reflected as described by Caldwell (1955), If not then , incision of the mylohyoid muscle fibres and supraperiosteal dissection will permit the extention of the lingual sulcus as described by Trauner (1963) Augmentation A. Mandibular augmentation 1. Superior bone augmentation- Bone grafts, cartilage grafts or alloplastic grafts 2. Inferior border augmentation- bone grafts or cartilage grafts 3. Interpositional or sandwich grafts- bone, cartilage or hydroxyapatite blocks 4. Visor osteotomy 5. Onlay grafting- autogenoue, alloplastic or allogenic material B. Maxillary augmentation procedures 1. Onlay bone grafting: autogenous/allogenic materials 2. Onlay grafting of alloplastic materials 3. Interpositional or sandwich grafts 4. Sinus lift procedure Augmentation in combination with orthognathic surgery 1. Mandibular osteotomy procedures 2. Maxillary osteotomy procedures 3. Combination procedures Mandibular augmentation Superior border grafting: Describe by davis(1970) Used 15cm autogenous rib grafts Rib is scored at the cortex and adapted to the shape of the mandible and fixed with transosseous or circummandibular wiring The other rib graft is made into corticocancellous particles and moulded around the first rib graft Inferior border grafting: Indicated when the alveolar ridge is less than 5 to 8 mm in height and is at risk of pathological fractures First described by Marx and Sanders and modified by Quinn Bilateral supraclavicular incision made and dissection in subplatysmal plane done upt inferior border of the mandibke A freeze dried cadaveric mandible is hollowed out and multiple perforations made into it to allow it for revascularization and is used as a tray The cadaveric bone is then filled with cancellous bone graft harvested from iliac crest and is fixed to the mandible using circummandibular wiring Interpositional grafts/sandwich grafting A horizontal osteotomy is performed in residual maxilla or mandible Allogenic bone/ hydroxyapatite grafts can be used to augment the jaw. Secondary vestibuloplasty procedurs maybe necessary Onlay grafting Used when adequate height is present but width of the jaw is inadequate Oldest technique of onlay grafting advocated by Obwegeser using allograft(hydroxyapatite) through submucosal vestibuloplasty. After creating a submucosal tunnel in the midline hydroxapatite crystals mixed with saline/blood is injected via a syringe into the tunnel. Visor osteotomy Goal of this procedure is to increase the height of the mandibular ridge for denture support. Consists of central splitting of the mandible in the buccolingual dimension and the superior postioning of the lingual section of the mandible which is wired into position Cancellous bone is placed at the outer cortex over the superior labial junction for improving the contour Modified Visor osteotomy Consists of splitting the mandible buccolingually using a vertical osteotomy only in the posterior region and a horizontal osteotomy in the anterior region Sinus lift procedures or sinus grafts Used to assist placements of osseointegrated implants in the posterior maxilla. In older patients the sinus floor is lowered almost to the level of the alveolar crest due to pneumatization Thus to improve support the sinus floor is lifted up surgically and a bone graft is placed between sinus lining and the inner aspect of the alveolar crest Augmentation in combination with orthognathic procedures Anterior maxillary osteotomies Total lefort I osteotomy with interpostional grafts Le fort I osteotomy