Implant surgeries to overcome anatomic difficulties ii / dental implant courses by Indian dental academy

IMPLANT SURGERIES TO
OVERCOME ANATOMIC
DIFFICULTIES
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS
 INTRODUCTION
 GUIDED TISSUE REGENERATION.
 RIDGE AUGMENTATION.
 MAXILLARY SINUS LIFT TECHNIQUE
 INFERIOR ALVEOLAR CANAL LATERALIZATION
 MENTAL NERVE DISTALIZATION
 CONCLUSION
 BIBILOGRAPHY

INTRODUCTION
The goal of modern dentistry is to restore the patient to
normal contour, function, comfort, esthetics, speech and health
regardless of the atrophy, disease or injury of the
stomatognathic system.
As a result of continued research in treatment
planning, implant designs, materials and techniques
predictable success is now reality for rehabilitation of many
challenging clinical situation.

Various techniques to over come anatomic difficulties
are:
1. Guided tissue regeneration.
2. Ridge augmentation.
3. Maxillary sinus lift technique
4. Inferior alveolar canal lateralization
5. Mental nerve distalization

Guided tissue regeneration :
It is a process used in regeneration of periodontal
supporting structures around natural tooth that have been lost
as a result of inflammatory diseases or trauma - MELCHER

MECHANISM OF GTR

 Barrier to prevent other tissues, especially connective tissue,
from entering the intended site of bone reformation and from
interfering with osteogenesis and direct bone formation
 Provide additional wound coverage, and provide added
stability and protection of the blood clot.
 Also provide a tent- like area for the blood clot, creating a
space under the surgical flap that will act as the scaffold for
ingrowth of cells and blood vessels from the base of the lesion.

The principles of membrane barrier techniques are to facilitate:
1. Augmentation of alveolar ridge defects
2. Improve bone healing around dental Implants,
3. Induce complete bone regeneration,
4. Improve bone grafting results, and
5. Treat failing implants

Indications
 Various implant defects
 Fenestrations
 Dehiscence
 Residual intra osseous defect
 Extraction socket defect

Materials used
 Non-resorbable
1. cellulose filter ( millipore)
2. e-PTFE (goretex)

Resorbable
Degradation through enzymatic activity (biodegradation) or
hydrolization (bioabsorption) as a cellular response from the
surrounding tissue.
They include
1. collagen membranes,
2. polylactic acid,
3. polyglycolic acid,
4. synthetic liquid polymer,
5. polyglactin,
6. calcium sulfate.

RIDGE AUGMENTATION

Aims
Restoration of optimum :
1. Ridge height and width,
2. Ridge form,
3. Vestibular depth
4. Optimum denture bearing area
 Protection of neurovascular bundle
 Establishment of proper interarch relationship.
 Improvement of retention and stability of denture.
 Improve the patient comfort for wearing the denture.

Limitations
 Physical condition of the patient
 Metabolism of the patient (healing capacity)
 Nutritional deficiencies.
 Inadequate soft tissue coverage.
 Compliance of the patient for major surgery.

Graft materials
 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

Augmentation procedures :
1. superior border grafting
2. inferior border grafting
3. interpositional bone graft
4. visor osteotomy
5. onlay grafting.

SUPERIOR BORDER GRAFTING
 Davis
 Two 15 cm autogenous rib grafts

DISADVANTAGES
 Second surgical site necessary.
 Continued resorption of the grafted sites.
 Soft tissue dehiscence or limitation

INFERIOR BORDER GRAFTING
 Indicated when ridge height is less than 5-8mm and risk of
pathological fracture.
 Used for reconstruction of mandible following resection,
augmentation of atropic ridge and subsequent placement of
implants

 Supraclavicular incision from
mastoid to mastoid region.
 A freeze-dried allogenic cadaver
mandible is hollowed out and
multiple perforations made into it to
allow for revascularization of the
packed cancellous bone graft. This
allogenic mandible will be used as a
tray. The cancellous bone graft is
harvested from the iliac crest. The
cadaver mandible is then filled with
autogenous cancellous graft particles
and is fixed to the inferior border
with 2-0 vicryl sutures, by
circummandibular fixation.

ADVANTAGES
 Since no surgery is done intraorally, patient's old dentures
can be used as transitional dentures
 By using this technique 11 to 17 mm of bone augmentation
can be achieved with a resorption rate of only 5 per cent
over the first several years.
 Increased bone height to accommodate implant surgery
 Extraoral flap gives adequate tissue coverage

Interpositional Bone Grafts
 Sandwich Grafting
 During this procedure, a horizontal
osteotomy is performed, splitting of the
residual maxilla or mandible and bone
is grafted into this osteotomy gap.
 In mandible, sandwich technique is
mainly used for augmentation of the
anterior mandible, between the mental
foramina. The autogenous or allogenic
bone or hydroxyapatite grafts can be
used successfully. Delivery of the
prosthetic appliance is delayed 3 to 5
months for allowing the remodeling of
the bone.

Advantages
 Less resorption rate than onlay grafting.
 More predictable long-term results.
 Decreased incidence of nerve paraesthesia than the visor
osteotomy.
 Can be used in conjunction with osseointegrated implants.

Onlay Grafting
 Done when adequate height but inadequate width.
 Two techniques
1. Oldest technique for onlay augmentation with
hydroxyapatite advocated via submucosal vestibuloplasty
technique. After creating a tunnel via midline, a putty is
formed of hydroxyapatite crystals, mixed with saline/blood,
and is injected via syringe into the sub-mucosal tunnel.

Technique 2 :
 A high vestibular incision is given and mucoperiosteal flap is
reflected to expose the defect.
 Small perforations are made in the external cortex by using small
round bur to create bleeding and promotion of clot formation and
neovascularization.
 The grafting material is placed/ moulded over the external cortex.
Placement of barrier membrane helps in regeneration and
preservation of the graft.

Visor Osteotomy

Visor Osteotomy
Advantage
Eighty percent of the height is maintained at the end of 3-5
years.
Disadvantages
 Nerve paraesthesia and dysesthesia.
 Need for hospitalization.
 Donor site morbidity.
 Inability to wear the dentures for 3 to 5 months following
surgery.

SINUS LIFT TECHNIQUE
 Hilt Tatum.

INDICATIONS
 Implant placement in areas of insufficient bone volume
 Oroantral fistula repair.
 Alveolar cleft reconstruction.
 Cancer reconstruction for craniofacial prostheses.

GENERAL MEDICAL CONTRAINDICATIONS
1. Radiation treatment to the maxillary region.
2. sepsis
3. Severe medical fragility.
4. uncontrolled systemic disease
5. excessive tobacco abuse
6. excessive alcohol or substance abuse
7. Psycophobias.

LOCAL FACTORS
 Maxillary sinus infections
 Chronic sinusitis
 Odontogenic infections
 Inflammatory or pathologic lesions
 Severe allergic rhinitis

ORIGINAL METHOD

New technique
Oval osteotomy in the lateral wall of the maxillary sinus. After completion of the osteotomy, the bony
window is removed, and the intact sinus membrane
can be visualized.

The bone graft material is placed into the sinus.

The newly formed bone, and the elevated sinus floor.

Benefits
 Reconstruct the highly atrophic posterior maxilla
 Replace the patient's removable prosthesis
 Stabilize the anterior residual dentition by reconstructing the
entire arch
 Reduce the continuous progressive atrophy of the posterior
alveolar ridge

complications
Sinus membrane perforation is a complication of
sinus elevation surgery. in this image a small (1-2 mm)
perforation can be observed
A large perforation was created by removal of the
bony window with the underlying sinus membrane. In
a case of such a large perforation, the sinus elevation
procedure should be aborted.

Complications
 Dehiscence with loss of the graft material
 Dehiscence with exposure of the barrier membrane
 Infection
 Potential loss of implants

 Gaber et al did a study on potential alterations of voice quality
following sinus elevation For the majority of patients, slight
changes of the voice pattern are of no importance. However,
for voice professionals, whose voices have become part of
their distinctive profession or trademark, minimal changes
may have dramatic consequences. This specific group of
patients, such as speakers, actors and singers, depend on the
particular quality and timbre of their voice for their livelihood.

INFERIOR ALVEOLAR NERVE LATERALIZATION

NERVE ANATOMY
 Solar documented Two different types of intraosseous path of
the mental nerve

DISTALIZATION OF THE MENTAL NEUROVASCULAR
BUNDLE

LIMITATIONS
 These procedures are technically difficult and therefore not suited
for every doctor.
 Implant practitioners who have the clinical experience, anatomic
knowledge, and ability to treat potential interoperative and
postoperative complications are the only ones equipped to perform
these procedures.
 Nerve damage is a significant risk of the procedures. Both the
surgical manipulation of the neurovascular bundle and the overall
surgical procedure can cause postoperative nerve deficits.

 Each patient should be advised of the risk for permanent
nerve deficits, which include anesthesia, paresthesia, dyses
thesia, and hyperesthesia.
 Fracture of the mandible, although rare, is also a risk. The
vast majority of these patients have advanced degrees of
atrophy in this area of the mandible.

CONCLUSION
Patients undergoing these procedures usually displays
post operative neurologic deficiency. Periodic assessment of
these patients are utmost important. Without the benefits of
CT scans and three dimensional reformatted imaging, these
techniques are difficult, if not impossible, to perform.
However, this technology has made these procedures a viable
option when performed by a skilled and knowledgeable
surgeon in appropriately selected cases.

BIBLIOGRAPHY
 Charles A.Babbush: Dental Implants The Art and Science.
 Carl. E. Meish – Implant dentistry
 Block Kent Guerra: Implants in Dentistry Essentials of
Endosseous Implants for Maxillofacial Reconstruction.
 Block: Color Atlas of Dental Implant Surgery.
 Neelima Anil Malik: Textbook of Oral Maxillofacial
Surgery
 Jensen: The Sinus Bone Graft.

 Charles A.Babbush ; Transpositioning and repositioning the
inferior alveolar and mental nerves in conjunction with endosteal
implant reconstruction; Periodontology 2000, Vol. 17, 1998,
183-190
 Ellegaard et al; Implant therapy involving maxillary sinus lift in
periodontally compromised patient; Clin Oral Impl Res
1997;8;305315 .
 Eliaz Kaufman: Maxillary Sinus Elevation Surgery: An
Overview; j Esthet Restor Dent 2003; 15:272283
 Gabor et al: Effects of sinus lifting on voice quality: Clin. Oral
Impl. Res. 14, 2003 / 767–774
.

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