PREPROSTHETIC SURGERY 4th Year Prof. Dr. Khaled Atef Elhayes Prof. Oral Maxillofacial Surgery Faculty of Oral & Dental Medicine Prof. Dr. Cairo/ Khaled University Elhayes REPROSTHETIC P s U r G e ry Definition: It’s corrective and preventive operations performed before denture construction and placement to create proper support, stability and retention for prosthetic appliance. * Ideal requirement for edentulous ridge: 1- Adequate bone support: . No v-shape ridge (should be U-shape). No sharp edge . No bone irregularities. No bony undercuts . No bony exostosis. 2- Adequate keratinized attached mucosal coverage: . No flabby ridge. No hypertrophy. Adequate Vestibular depth. No high frenum or muscle attachment. No scar bands. No ulceration. 3- Good relationship between maxilla & mandible in antero-posterior, transverse and vertical dimensions. 4- Offering protection to neurovascular bundle*and sinus. 5- Freedom from pathosis. * Objectives (Aim) of Preprosthetic surgery: 1. Restore normal masticatory function. 2. Restore esthetics. 3. Restore ideal bone support with broad ridge form. 4. Adequate palatal vault form. 5. Restore Proper S.T support. 6. Adequate vestibular depth. 7. Restore proper inter-arch relation ship. 8. Offering protection to neurovascular bundle. 9. Remove any pathosis. Factors affecting bone resorption: 1- Local factors: a. Long standing denture wearing. b. TraumaProf. Dr. / Khaled Elhayes c. Previous dento-alveolar surgery. 1 (42) — CHAPTER (3) 2- Systemic factors: a) Hormonal disease: as diabetes mellitus, hyperparathyroidism. b) Osteoporosis. c) Nutritional deficiency. *Complications of Edentulous Bone Loss: 1. Effect on bone . Loss of alveolar bone. Loss of basal bone and increase risk of basal bone fracture. 2. Effect on soft tissue . Hypertrophy and flabby ridge . High ms. Attachment and Decrease sulcus depth. 3. Increase inter-arch relation ship. 4. ↓ Denture retention and stability 5. ↑ Patient discomfort. Preoverative Patient Evaluation I- History: • Chief complaint. • Patient Esthetic and functional goals . • Patient expectation of surgical ttt. • Psychological adaptability toward P.D and C.D. II- Clinical examination (Intra-oral or Extra-oral): • Bony tissue (ridge hight, width and contour). • Soft tissue: quality, flabby ridge, scars,….etc. • Vestibular depth and ms attachment. • Inter-arch relationships. • Existing teeth relations. III- Radiographic Examination: By panorama to denote: • Pathological lesions • Remaining roots. • Impactions. • Pathosis. Prof.• Pneumatization Dr. of the sinus /. Khaled Elhayes 2 PREPROSTHETIC SURGERY — (43) IV- Laboratory investigation: • Blood sugar level. • Parathyroid hormones. • Serum calcium and phosphate levels. • Alkaline phosphatase enzyme. Classifications of surgical procedures I. Preventive surgical procedures: 1. Routine measures during extraction 2. Alveoloplasty Vs alveolotomy and alveolectomy. II. Corrective surgical procedures: A) hard tissue abnormality: 1- Torus palatinus. 2. Torus mandibularis. 3. Bony enlarged maxillary tuberosity. 4- Mylohyoid ridge (lingual balcony). 5- Bony prominence and bony undercuts. 6- Correction of knife edge ridge. B) soft tissue abnormality: 1- Labial frenum 2- Lingual frenum. 3- Fibrous enlarged Maxillary tuberosity. 4- Flabby ridge. 5- Denture fissuratum. 6- Inflammatory papillary hyperplasia of the palate. C) Surgical correction of flat ridge: 1- Relative ridge hightening (vestibuloplasty). Submucosal vestibuloplasty. Secondary epithalization vestibuloplasty. Grafted vestibuloplasty. 2-AbsoluteProf. ridge hightening Dr. ( ridge / augmentation). Khaled Elhayes 3 (44) — CHAPTER (3) I. Preventive surgical procedures: 1. Routine measures during extraction: Aim: promote healing and preserve shape of alveolar ridge. • Treat any gingival inflammation before extraction. Remove any projecting interseptal bone . Remove loose pieces of alveolar bone. Squeeze the bony socket to avoid undercuts and for better healing. Loosely tied suture if necessary 2. Alveoloplasty: Definitions: Alveoloplasty: It’s surgical contouring of alveolar ridge. Alveolotomy: it’s cutting into the alveolar process. e.g. during removal of remaining root, cyst,…… Alveolectomy: it’s complete surgical excision of alveolar bone e.g. neoplasm or radiotherapy. Indications: Remove bone irregularities or undercuts Techniques: A- Recontouring of rough and sharp bone edges 1. Paraperiosteal infiltration anesthesia. 2. crestal incision using BP blade NO.15. 3. Reflection of mucoperisosteum using mucoperiosteal elevator. 4. Trimming sharp bony edges using bone rongeur. 5. Filing & irrigation. 6. Remove excess soft tissue. 7. Suturing. (interrupted suture) B- Alveloplasty for multiple teeth extraction: i- Interseptal alveoloplasty 1. L.A. 2. Gingival incision around the teeth (vertical releasing incisions may be used) Prof.3. Reflection of mucoperisosteumDr. / usingKhaled mucoperiosteal elevator Elhayes. 4 PREPROSTHETIC SURGERY — (45) 4. Teeth extraction. 5. Cutting interseptal bone by rongeur. 6. bony groove may be done in the labial plate followed by green stick fracture to yield labial plate toward the lingual plate by compression 7. Filing & irrigation. 8. Remove excess soft tissue. 9. Suturing (interrupted suture) ii- Labial plate alveoloplasty (radical alveoloplasty): Indication: maxillary prognathism Technique: 1. Paraperiosteal infiltration anesthesia. 2. Gingival incision extending one tooth distal 3. on either sides using lancet NO.15. 4. Reflection of mucoperisosteum using mucoperiosteal elevator. 5. Teeth extraction. 6. Cutting labial plate of bone and interseptal bone using bone rongeur. 7. Trimming of the palatal bone and beveling is done. 8. Filing & irrigation. 9. Remove excess soft tissue. 10. suturing ( interrupted suture) 11. Now labial mucoperiosteum rests on palatal bone. Prof. Dr. / Khaled Elhayes 5 (46) — CHAPTER (3) II. Corrective surgical procedures: A) Hard tissue abnormality: Exostoses Exostoses are generally bony protuberances, which develop in various areas of the jaw. They are not considered real neoplasms, but dysplastic exophytic lesions. The etiology of these lesions remains unknown, even though evidence suggests that genetic and environmental factors determine their development. Exostoses are classified into three types: (1) torus palatinus, (2) torus mandibularis, and (3) multiple exostoses. Torus Palatinus This exostosis is localized at the center of the hard palate and the exact causes remain unknown. Clinically, they are common asymptomatic bone protuberances, covered by normal mucosa (Fig. 3.1). They vary in size, and the shape ranges from a single discrete exostosis, to multiloculated, to bosselated, to irregular in shape. They usually do not require any special therapy, except for edentulous patients in need of prosthetic rehabilitation, and in cases where the patient is greatly bothered by the exostoses. Surgical Technique. In order to remove the lesion surgically, an incision is made along the midline of the palate, which is composed of two anterior and posterior oblique incisions (Fig. 3.2). The incision is designed so as to avoid injuring branches of the palatine artery, but also so that there is adequate visualization of, and access to, the surgical field without tension and injurious manipulations during the procedure. After reflection, the flaps are retracted with the aid of sutures or broad periosteal elevators. After complete exposure of the lesion, it is sectioned with a fissure bur and the segments are individually removed using a monobevel chisel (Figs. 3.3, 3.4). More specifically, the chisel is positioned at the base of the exostosis with the bevel in contact with the palatal bone and, thereafter, each segment of the lesion is removed after a slight blow with the mallet (Fig. 3.5). After smoothing the bone surface, excess soft tissue is trimmed and, after copious irrigation with saline solution, the flaps are repositioned and sutured with interrupted sutures (Figs. 3.6–3.8). If the torus palatinus is small in size, the incision for creation of the flap is again made along the midline, but only with anterior oblique releasing incisions. The procedure is thenProf. performed in exactly Dr. the same / way Khaled as that already mentioned. Elhayes 6 PREPROSTHETIC SURGERY — (47) Fig. 3.1 a,b. Torus palatinus. a Diagrammatic illustration. b Clinical photograph Fig. 3.2 a,b. Surgical procedure for removal of torus palatinus. Incision along the midline of the palate with antero- lateral and posterolateral incisions. a Diagrammatic illustration. b Clinical photograph Fig. 3.3 a,b. Mucoperiosteal flaps on either side of the exostosis. Retraction of flaps during the surgical procedure is achievedwith the help of traction sutures. a Diagrammatic illustration. b Clinical photograph Prof. Dr. / Khaled Elhayes 7 (48) — CHAPTER (3) Fig. 3.4 a,b. Sectioning of the lesion into smaller parts using a fissure bur. a Diagrammatic illustration. b Clinical photograph Fig. 3.5 a,b. Removal of the exostosis in fragments with a monobevel chisel. a Diagrammatic illustration. b Clinical photograph Fig.Prof. 3.6 a,b. Smoothing ofDr. the bone surface /with aKhaled bone bur. a Diagrammatic illustration. Elhayes b Clinical photograph 8 PREPROSTHETIC SURGERY — (49) Fig. 3.7 a,b. Operation site after the placement of sutures. a Diagrammatic illustration. b Clinical photograph Torus Mandibularis Torus mandibularis is an exostosis of unknown etiology. It is localized in the lingual aspect of the body of the mandible, either on one side or more