1. PRE PROSTHETIC SURGERY HARD TISSUE PROCEDURES Presented by : Presented by : ANSHIKA GROVER ANSHIKA GROVER P.G. IInd Year P.G. IInd Year Dept. Of OMFS Dept. Of OMFS 1

2. Contents  Introduction  Definition  Aims Of Pre Prosthetic Surgery  Objectives  Changes In Edentulous Patients  History & Clinical Examination  Hard Tissue Procedures –  Alveolectomy  Alveoloplasty 2

3.  Reduction Of Genial Tubercle  Mylohyoid Ridge Reduction  Excision Of Torus - Torus palatinus - Torus palatinus - Torus Mandibularis - Torus Mandibularis  Maxillary Tuberosity Reducton  Ridge Augmentation Procedures  References 3

4. Introduction Making of satisfactory dentures starts with extraction of teeth. Beers (1876) was another pioneer who advocated “Excisions of alveolus after extraction of teeth”. Pre Prosthetic surgery has always been an essential part of the preparation of the alveolar ridges for dentures. 4

5. DEFINITION Pre-prosthetic surgery is carried out to reform/redesign denture bearing area to create an oral environment to support a functional prosthetic appliance. 5

6. AIMS Of Pre Prosthetic Surgery Provide adequate bony support Provide adequate soft tissue support Elimination of preexisting bony deformities Correction of maxillary and mandibular ridge relationship Elimination of preexisting soft tissue deformities Relocation of frenal / muscle attachments Establishment of correct vestibular depth 6

7. Objectives Pre prosthetic surgery is to create proper supporting structures for subsequent placement of prosthetic appliances. Best Denture support has the following characteristics:- No evidence of intra oral or extra oral pathologic conditions. Proper inter arch jaw relationship. Alveolar process that is as large as possible. (ideal-broad U-shaped ). No bony or soft tissue protuberances or undercuts. 7

8. Adequate palatal vault form. Proper posterior tuberosity notching. Adequate attached keratinized mucosa in the primary denture bearing area. Adequate vestibular depth for prosthesis extension. Added strength where mandibular fracture may occur. Adequate bony support to facilitate implant placement when necessary. 8

9. Changes in edentulous patient The effects of aging on the edentulous patient may include – 1.) Oral mucosa & skin changes. 2) Residual bone & maxillomandibular relation changes. 3) Tongue & taste changes. 4)Salivary flow changes & nutritional impairment. 5) Change in psychological outlook. 9

10. Residual bone changes The gross reduction of the height of maxillary & mandibular residual ridges is often due to long term wear of complete denture.  Disuse Atrophy -  Flat residual ridges distal to natural teeth are frequently seen & the reduction in the height of ridge in these regions is attributed to disuse atrophy. 10

11.  Maxilla  Maxilla –  Maxillary teeth generally flair downward & outward, so bone reduction is generally upward & inward.  Since the outer cortical plate is thinner than the inner cortical plate, resorption from the outer cortex tends to be greater & more rapid. 11

12.  Mandible  Mandible –  The anterior mandibular teeth generally inclined upward & forward to the occlusal plane while posteriors are vertical or slightly lingually inclined.  Outer cortex is thicker than lingual cortex except in molar region & the width is greatest at the inferior border of the mandible.  So mandibular residual ridge appears to migrate lingually & inferiorly in anterior region & buccaly in posterior region. 12

13. Maxillomandibular Relations Due difference in the pattern of bone loss there is difference in relative jaw sizes causing difficulty in the placement of artificial teeth jeopardizing denture support & stability. Changes occur in vertical maxillomandibular relation also. 13

14. History & Clinical Examination Includes a thorough medical and dental history and clinical examination of patient Should be supplemented with radiographs and study casts. 1.) Chief complaint 2.) Patient’s aesthetic & functional goals 3.) Psychological status 4.) Previous experience 5.) General health status, any medications being taken & risk values should be evaluated. 14

15. Clinical Examination Extra oral examination –  Presence of unsupported upper lip.  Poor vermilion show.  Loss of nasolabial fold.  Poor or obtuse naso labial angle.  Excessive lower lip show. 15

16.  Intra oral examination 1.) Soft tissue examination – A.) Quantity & quality of overlying tissues B.) Palpation of vestibule C.) Muscle & frenal attachment with alveolar crest. D.) Presence of any soft tissue pathology E.) Examination of palatal vault & soft palate. 16

17. 2.) Hard tissue examination – A.) Ridge form & contour B.) Presence of any gross irregularities in the ridge. C.) Inter arch relationship D.) Maxillary tuberosity examination 17

18. Radiological Evaluation Helps in detecting any embedded root apices & impacted teeth. Presence of cyst & tumor can be assessed. Position of mental foramen & density of maxillary & mandibular bone can be assessed. Radiological assessment should include – 1.) OPG 2.) Lateral cephalogram 3.) 3D CT scan 18

19. Alveolectomy  Surgical removal or trimming of alveolar process.  To correct the irregularities of alveolar ridge after the removal of one or more teeth.  To prepare the residual ridge for reception of dentures. 19

20. Trimmed with round bur and rongeuer and smoothened with a file The term alveoloplasty has been adopted to signify recontouring of alveolar process rather than its removal. Minimum bone should be trimmed, too much bone loss will result into poor denture base. 20

21. Alveoloplasty Surgical recontouring of alveolar process. Objective is to provide the optimal ridge contour for prosthesis support. This should be counter balanced with the ultimate goal of preserving as much alveolar bone as possible for continued denture stability. 21

22. Patient age must be considered, the bone of younger patients is more elastic and will be more prone to resorption from atrophy and disuse over a longer number of years than the older patients. Thus less amount of bone should be removed in younger patients. Alveoloplasty should be delayed 4-6 weeks until new bone fills the socket. Much less bone will removed by delayed alveoloplasty. 22

23. Types of alveoloplasty Alveolar compression  Alveolar compression  Simple Alveoloplasty  Dean’s Intraseptal Alveoloplasty  Obwegeser’s modification  Alveoloplaasty After Post Extraction Healing 23

24. Alveolar compression Easiest and quickest form. Compression of inner and outer cortical plates between the fingers. Compression reduces the width of the socket. 24

25. Alveoloplasty After Single Tooth Extraction  Incision is placed along the crest of the alveolar ridge extends through the extraction site & a full thickness mucoperiosteal flap is elevated.  Projecting bone is carefully removed with rongeur or bur & area is smoothened with the bone file.  Soft tissues can be removed from the mesial & distal sides of the socket for a linear closure.  Irrigation & suturing should be performed. 25

26. Alveoloplasty With Multiple Extraction  Multiple teeth to be extracted in a single sitting & no other bony irregularities are present.  Buccal & lingual plates should be compressed with digital pressure.  Entire ridge is palpated for sharp bony spicules & undercuts. 26

27.  Trimming & smoothening is done with rongeur & bone file.  Excess redundant tissue is trimmed with surgical scissor.  Intrupted suturing should be done. 27

28. Intraseptal Alveloplasty/Dean’s Alveloplasty Thoma uses the term “Intercortical”, between the cortical plates rather than intraseptal to describe the removal of interradicular(between the roots)bone. Others used the term “Crush Technique” Used in maxilla only in anterior region. 28

29. Technique used to reduce gross maxillary over jet. Best used where maxillary ridge presents with an undercut to the depth of labial vestibule. Maintains stress bearing cortical bone intact. Maintain a periosteal attachment to the labial plate of bone. Indicated where adequate bone height present but undercut is present. 29

30. Technique 30

31. Obwegeser’s modification for Intraseptal alveoloplasty  Obwegeser’s (1966) suggested the modification of Dean’s technique for cases of extreme premaxillary protrusion.  Repositioning of both labial & palatal cortices.  After cutting the intraseptal bone, an inverted cone bur is used to widen the base of the socket.  With a small disc or bur, a horizontal cuts are made at the base of the extraction sockets in the labial & palatal cortices. 31

32. With the straight fissure bur, Vertical cuts are made bilaterally in both the labial and palatal cortices in the area distal to canine sockets. With the digital pressure, both labial & palatal cortices are compressed together and sutures given. 32

33. Alveloplasty After Post Extraction Healing Multiple extractions are carried out at different times which results in irregular ridge. Resulting in a knife edge ridge or one with sharp bony spicules,which are painful to touch. Crestal incision is given and mucoperiosteal flap is raised, bone trimmed and suturing done. 33

34. Reduction of Genial tubercles Genial tubercles, bony attachments of genioglosssus muscle, can become area of interference due to gross resorption of mandibular ridge. In some cases it may be at the level of alveolar crest, where slightest movement dislodges the denture. 34

35. Technique  LA infilteration & bilateral lingual nerve blocks provide adequate anesthesia.  A crestal incision is made from each premolar area to the middle of the mandible.  Full thickness mucoperiosteal flap is dissected lingually to expose the genial tubercle.  Repositioning the genial muscles with catgut before separating the tubercle.  Smoothening with a bur or rongeur followed by bone file removes the genial tubercle. 35

36. Reduction of Mylohyoid Ridge Gillies states that the mylohyoid ridge should be reduced whenever the ridge is found to be same level or higher level than the alveolar process. Roberts advocates the reduction of the mylohyoid ridge and the extension of posterior lingual denture flange in to retromylohyoid fossa to increase mandibular denture stability. 36

37. Technique Incision is made on crest of alveolar ridge. Mucoperiosteum is raised Rongeur is used to reduce the sharp bony margin Bone file is used to smoothen the area Sutures are placed to close the incision 37

38. Excision of Torus Torus is exostosis/ over growth of cortical or cortico cancellous bone which is localised to particular area, usually benign and asymptomatic and slow growing. Torus palatinus Torus palatinus Torus Mandibularis Torus Mandibularis 38

39. Indications for Excision of Tori Extremely large torus filling the palatal vault. Large torus extending beyond the posterior palatal seal. Ulceration/traumatisation of overlying mucosa. Interference with function - speech, deglutition. 39

40. Torus palatinus Is a benign, slow growing, bony projection of palatine processes of maxillae. It occurs bilaterally along the median suture on the hard palate. Etiology is unknown 40

41. Palatal torus is a bony mass with dense cortical surface. Torus grows slowly and attains maximum size by middle decade. Size and shape are variable. Mucosa covering the torus is thin. Because of scarcity of submucosal CT, vascular supply is poor in comparison with other areas. 41

42. Technique for excision L.A- bilateral greater palatine and incisive nerve blocks are given. Anterioposterior linear incisions are made. Y shaped releasing incisions are given. Mucoperiosteal flaps are raised. 42

43. Torus should never be removed enmasse, because of proximity to nasal floor. Division of torus into multiple segments, small pieces are removed with rongeur forceps, or a mallet and chisel. Prefabricated splint is used to prevent pressure necrosis and to support the thin mucosa. 43

44. Torus Mandibularis Usually occurs bilaterally on the medial surface of body and alveolar process of mandible. Located in canine - premolar region. Etiology is unknown but it is thought to be the result of functional reaction to masticatory stress. 44

45. Technique for removal Area is anesthetized by bilateral inferior alveolar, lingual and buccal infiltration. Incision over the alveolar ridge in lower premolar region. Muccoperiosteal flap is raised. 45

46.  Excess bone is removed by cheisel & mallet and rongeur.  Smoothened by bone file.  Sutures placed.  Surgical splint is not necessary because mucoperiosteal covering can be readapted.  The normal position of tongue helps to maintain the tissue in correct position. 46

47. Maxillary tuberosity reduction Excess horizontal and vertical bony or soft tissue in the maxillary tuberosity region may interfere with denture construction. Technique –  LA – Infiltration or Post. Sup. Alveolar & Greater palatine nerve blocks.  Crestal incision from tuberosity to premolar region. 47

48. 48  Mucoperiosteal flap is raised.  Excess bone is then removed from the crest of the ridge & from the buccal plate.  After the desired contour is achieved the excess soft tissue is trimmed.  Sutures placed.

49. Ridge augmentation Mandibular augmentation : Mandibular augmentation :  Superior border  Inferior border  Interpostional bone grafts  Visor osteotomy  Onlay grafting 49

50. Maxillary augmentation  Onlay bone grafting  Interpostional grafts  Sinus lift procedure 50

51. Materials used for Augmentation Autogenous bone graft- iliac crest,rib grafts Allogenic bone grafts-freeze dried cadaver bone Alloplastic material – hydroxyapatite Metal mesh with autogenous cancellous bone Metal mesh with hydroxyapatite 51

52. Superior border augmentation Indicated when mental foramen is situated in the superior border. Autogenous bone graft is used. Donor considerations- two rib segments about 15cm long,from 5 th & 9 th rib Rib graft is fixed to the mandible either with transosseus wiring or circum mandibular wiring 52

53.  Disadvantages  Donor site morbidity  Second surgical site necessary  Continued resorption of grafted site 53

54. Inferior border augmentation First described by Sanders & Cox in (1976). Indication – Indication –  When alveolar ridge height is less than 5mm to 8mm and at risk of pathological fracture.  Management of malunion or non union of edentulous mandible. 54 Inferior Border Augmentation using composite cadaveric mandible combined with Autogenous cancellous bone

55. Procedure  Continuous submandibular incision is made from angle to angle region.  Subplatysmal dissection is done to the inferior border of the mandible.  Incision through periosteum is made.  Two ribs obtained are abutted against the buccal & lingual aspect of the inferior border.  Graft material is fixed to mandible by circummandibular wiring. 55

56.  Advantage-  Does not obliterate the vestibule.  Interim denture can be worn immediately.  No change in vertical dimension.  Graft is not subjected to direct masticatory forces.  Disadvantages -  Will not correct the abnormalities of denture bearing areas.  Will not protect a highly placed mental nerve.  Donor site morbidity.  Resorption of graft.  Presence of scar. 56

57. Vertical / visor osteotomy First described by Harle to overcome the resorption of free onlay bone graft. Used when insufficient vertical mandibular bone height is present for horizontal osteotomy technique but adequate bone width is present 57

58. Technique Mandible is split vertically and lingual section is elevated to increase the mandibular height. Cancellous bone is placed to correct the contour and fill in the gaps in the elevated segment. Stainless steel wires hold segments in place for a period of 3- 4months. 58

59. Interpositional bone grafts Also known as modified visor osteotomy or sandwich grafting. The vertical osteotomy cut is made only in the posterior region to divide the segment buccolingually. A horizontal osteotomy is performed in the anterior mandible to divided the segment superiorly & inferiorly. Bone grafting is done into osteotomized gap, and two osteotomized segments are fixed with wires. 59

60. Advantages Advantages  Rate of resorption is less as compared to onlay grafts.  Incidence of nerve parasthesia is less.  More predictable long term results. 60

61. Onlay grafting When adequate height is present but width is inadequate for prosthesis. Autogenous bone graft or Allo graft like Hydroxyapatite crystals can be used. A tunnel is created via midline. A putty is formed of HA crystals mixed with saline and injected in to sub mucosal tunnel. 61

62. Sinus Lift procedure/Sinus Grafting Due to excessive pneumatization of the maxillary antrum & atrophy of the maxillary ridge, floor of the sinus comes close to the alveolar crest. Maxillary sinus lift procedure is carried out to lift the floor of the sinus lining by placing the graft in between the maxillary sinus lining and the floor of the maxillary antrum in the posterior aspect. 62

63. Material used for surgical procedure are – ILIAC crest cancellous graft Rib graft Hydroxyapatite Technique Technique  In 1977, Tatum was the first to perform the sinus lift operation.  A crestal incision is made from canine to maxillary tuberosity region with two vertical releasing incision.  Full thickness flap is raised.  Horizontal bony cut is made inferiorly 2- 4mm above the floor of the sinus. 63

64. Rectangular window cut is made to enter into the sinus. A vertical bony cut is made perpendicular to horizontal cut in the anterior region parallel to the lateral nasal wall. Another vertcal cut made posteriorly perpendicular to the inferior horizontal cut in the region of the maxillary buttress. 64

65. Two Vertical cuts are joined superiorly by a intrupted osteotomy cut to create a hinge bony window. A surgical curette is placed between the bone and antral lining in the inferior osteotomy cut. Bone is gently feel from inside of the lining of the sinus. The graft is inserted in floor of the sinus. Sutures placed. 65

66. ALVEOLAR RIDGE DISTRACTION One of the most common problem encountered during implant placement is deficient bone. Alveolar Distraction Osteogenesis is a surgical technique that is relatively uncomplicated & avoids the graft related complications. 66

67. Technique Under local anesthesia, a crestal mucoperiosteal incision is made followed by labial oblique mucoperiosteal incisions placed anterior and posterior to the distraction zone. A round burr is used to make a small trough along the crest. Bone cuts are made through the trough, and through the anterior and posterior vertical incisions without stripping mucoperiostium using chisel and mallete. 67

68. An osteotome is introduced crestally and the buccal plate is “green-stick” fractured bucally. The distractor is tapped into place and the wound is approximated with sutures. 68

69. The latency period  7 days  Then Distraction began 1 week later by turning the activating screw 2 turns per day  (0.5 mm X 2). After 10 day retention period for early bone “consolidation” will achieved to desired height of 10 mm. Stabilization 3 month  The distraction regenerate was well ossified and stable. 69

70. References  Contemporay Oral and Maxillofacial Surgery – Peterson.  Fonseca – volume 7  Prosthodontic treatment for edentulous patient-Boucher and Nalla Swamay  Fragiskors  oral and maxillofacial surgery - Daniel laskin  oral and maxillofacial surgery-Lars andersson 70

71. THANK YOU 71