Pre - prosthetic surgery- hard tissues

1. PRE PROSTHETIC
SURGERY- HARD TISSUES

2. Contents
 Introduction
 Objectives
 Patient evaluation and Treatment planning
 Evaluation of the supporting bony tissues
 Recontouring of alveolar ridges
 Maxillary tuberiosity reduction
 Buccal exostosis and excessive undercuts
 Lateral palatal exostosis
 Mylohyoid ridge reduction
 Tori removal
 Bone augmentation

3. Introduction
 Preprosthetic surgery refers to the surgical procedures that
can modify the oral anatomy to facilitate the retention of
conventional dentures.
 The ultimate goal of preprosthetic surgery is to prepare the
mouth to receive dental prosthesis by redesigning and
smoothing bony edges or areas and removing excess of
flabby soft tissues

4. Objectives
No evidence of intraoral and extraoral pathological
conditions.
 Proper inter arch jaw relationship
 Alveolar processes that are as large as possible and of
the proper configuration.
 No bony or soft tissue protuberances or undercuts
 Adequate palatal vault form
 Proper posterior tuberosity notching
 Adequate attached keratinized mucosa and adequate
vestibular depth.
 Protection of the neurovascular bundle

5. Preprosthetic procedures
 Ridge correction
 Alveoloplasty
 Maxillary tuberosity reduction
 Removal of exostosis
 Removal of undercuts
 Lateral palatal exostosis
 Mylohyoid reduction
 Genial tubercles reduction
 Removal of tori
 Ridge augmentation
 Maxillary
 Mandibular

6. Patient evaluation and treatment planning
 Preprosthetic surgical treatment must begin with a
proper case history and physical examination
 Special attention should be given to systemic diseases
that may be responsible for the severe degree of bone
resorption.
 Esthetic and functional goals of the patient must be
assessed carefully.
 Long term maintenance of the underlying tissues as well
as prosthetic appliances should be kept in mind.

7. Recontouring of alveolar bone
 Simple alveoloplasty
 Intraseptal or Dean’s alveoloplasty

8. ALVEOLOPLASTY
 Defined as surgical recontouring of alveolar process
Indications
 Patients with prominent and dense alveolar
bone undergoing extraction
 Prior to construction of an immediate denture
 The simplest form of alveoloplasty consists of compression of
the lateral walls of the extraction socket after simple tooth
removal

9.  Bony areas requiring recontouring should be exposed using an
envelop type of flap.
 A mucoperiosteal incision along the crest of the ridge with
adequate A-P extension is given
 Adequate visualization and access to the alveolar ridge
obtained
 Vertical incisions given if necessary
 Excessive flap reflection may result in devitalized areas of bone
which may resorb rapidly after surgery
 Recontouring can be accomplished with
Rongeur
Bone file
Bone bur in handpiece

10.  Copious saline irrigation should be done throughout the
recontouring procedure to avoid overheating and bone
necrosis
 After this the edges of the flap are trimmed and then sutured
with continuous or noncontinuous sutures.

11. RONGEUR
BONE BUR
BONE FILE

13. DEAN’S INTRASEPTAL ALVEOLOPLASTY
 This technique is best used in an area where the ridge is of relative
regular contour and adequate height but presents an undercut to the
depth of the labial vestibule.
 Performed during the time of extraction
Advantages :
1. Labial prominence is reduced without reducing the height of the
ridge
2. The periosteal attachment to the bone can be maintained hereby
reducing bone resorption
3. Muscle attachments are left undisturbed
Disadvantage :
1. Decrease in ridge thickness

15. MAXILLARY TUBEROSITY REDUCTION
 Excess tissue in the region of the maxillary tuberosity may become so
large that it:
 Impinge upon the mandible during mastication.
 Interfere with denture construction, insertion and seating
 Complication of tuberosity reduction
 -expanded tuberosity in proximity to sinus

17. Lateral palatal exostosis
 Presents problems in denture construction because of the undercut
created by the exostosis and narrowing of the palatal vault
Technique :
 Local anesthetic solution in the area of the greater palatine foramen
 Crestal incision made from the posterior aspect of the tuberosity
extending to the exostosis
 Reflection of the mucoperiostium
 Removal of excess bony projection by a bone file
 Saline irrigation
 Suturing

19. Mylohyoid ridge reduction
 Linear incision is made over the crest of the ridge in the
posterior aspect of the mandible
 Full thickness mucoperiosteal flap is elevated to expose the
muscles
 Bone file is used to remove the sharp prominance of the
mylohyoid ridge

21. Genial tubercle reduction
 Reduction required to
construct the
prosthesis properly
 If augmentation is to
be carried out,
tubercle left to add
support to the graft

22. Tori removal
 In the patient requiring complete or partial conventional
prosthetic restoration, tori maybe a significant
obstruction to insertion or interfere with the overall
comfort, fit, and function of the planned prosthesis.
 In the maxilla,bilateral greater palatine and incisive
blocks are given.

23.  A linear midline incision with posterior and anterior
vertical releases or a U-shaped incision in the palate
followed by a subperiosteal dissection is used to expose
the defect.
 Rotary instrumentation with a round acrylic bur may be
used for small areas; however, for large tori, the
treatment of choice is sectioning with a cross-cut fissure
bur.
 Once sectioned into several pieces, the torus is easily
removed with an osteotome

24.  Closure is performed with a resorbable suture.
 Presurgical fabrication of a thermoplastic stent, made
from dental models with the defect removed, in
combination with a tissue conditioner helps to eliminate
resulting dead space, increase patient comfort.
 Complications :-
Postoperative hematoma,
Perforation of the floor of
the nose
Necrosis of the flap

26. MANDIBULAR TORI
• Bilateral lingual and inferior
alveolar anesthesia is given
• Incision extending from 1 to
1.5cms beyond each tori is
given
• Always leave behind a band of
tissue attached to the midline
between the anterior extent of
the 2 incisions.
• When the torus has a small
pedunculated base, a mallet
and an osteotome is used to
cleave the tori from the medial
aspect of the mandible
• The direction of the initial bur
is parallel to the medial aspect
of the mandible to prevent
fracture of the lingual or
inferior cortex

27. • A bone file is then used to smoothen the lingual cortex
• Palpation is done to check for proper contour and presence of
any undercuts
• Continuous suturing is done and gauze packs are placed and
retained for the next 12 hrs
• The direction of the initial bur is parallel to the medial aspect
of the mandible to prevent fracture of the lingual or inferior
cortex
• A bone file is then used to smoothen the lingual cortex
• Palpation is done to check for proper contour and presence of
any undercuts
• Continuous suturing is done and gauze packs are placed and
retained for the next 12 hrs

28. Mandibular augmentation
 Augmentation grafting adds strength to an extremely deficient
mandible and improves the height of contour of the available
bone for implant placement on the denture bearing areas.
 The sources of graft material include autogenous or alloplastic
bone and alloplastic materials

29. Mandibular
augmentation
Superior
border
augmentation
Hydroxyapatite
augmentation
Osteopromotion
Inferior border
augmentation

30. Superior border augmentation
Thoma & Holland
technique:
Corticocalcellous iliac crest
blocks are contoured to
adapt to the configuration
of the mandible.
Then fixated with screws
and miniplates

31. Hydroxyapatite augmentation

32. Osteopromotion
 A membrane is used to cover an area where bone
regeneration is necessary
 By placing a membrane over the bone graft, faster
growing fibroblasts and epithelial cells are walled off
allowing the bone to grow in a relatively protected
environment.
 Currently, expanded polytetrafluoroethylene is used as a
membrane.

33. Maxillary
augmentation
Onlay bone
grafting
Hydroxyapatite
augmentation Sinus lifts
Interpositional
bone grafts

34. Onlay bone graft

35. Sinus lift
 Extension of the maxillary sinus into the alveolar ridge
may prevent placement of implants in the posterior
maxillary area because of insufficient bony support.
 A sinus lift procedure is a bony augmentation procedure
that places graft material inside the sinus and augments
the bony support in the alveolar ridge area.
 The graft is allowed to heal for 3 to 6 months after which
the first stage of implant placement can begin.