Dental Implant Surgery

Stage I & II Procedures

Moustafa El-Ghareeb BDS, MS Associate Clinical Professor Oral & Maxillofacial Surgery

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Osseointegration

A direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant (Brånemark, 1985)

Per-Ingvar Brånemark

Cortical bone

Cancellous bone

Osseointegration

Micromotion at the bone-implant interface beyond 150 μm results in fibrous encapsulation instead of osseointegration (Szmukler-Moncler et al. 1998)

Osseointegration Osseous Healing: •  Blood fills gap between implant and

damaged bone surface •  Blood clots with fibrin network

formation (Platelets) •  Inflammation (PMN’s & Macrophages) •  Resorption (Macrophages “ingest

inflammatory debris” & Osteoclasts “resorb damaged bone”)

•  Neovascularization (Endothelial cells) •  Migration/differentiation/ proliferation (MSC’s, fibroblasts &

osteoblasts) •  Osteoid & Woven bone (osteoblasts)

4-6 weeks after surgery •  Replacement of woven bone by

lamellar bone (osteoclasts & osteoblasts)

Osteoclast cutting cone: basic remodeling process for bone renewal

Basic multi-cellular unit

Osseointegration

Distant Osteogenesis only

Contact & Distant Osteogenesis

Machined Smooth Surface Rough or Enhanced Surface Improves Cell Attachment

Osseous Healing:

Osseointegration

Enhanced Surfaces: • Acid etched •  Sand blasted •  Titanium oxide

blasted •  HA coated • Anodized

Subtractive

Additive

SLA®

TiUnite®

TiOblast™

Acid Etched

Peri-Implant Soft Tissue Healing & Biology

•  Bone resorption occurs to

create a proper soft tissue seal around implants

•  The term biologic width is used when describing the soft tissue dimensions around implants

•  Epithelial cells are attached by hemidesmosomes & basal lamina

•  Collagen fibers are oriented parallel to the implant surface

CTA

Osseointegration Original Brånemark Protocol •  Implants must be sterile •  Made of highly biocompatible

material such as titanium (covered by a biologically inert TiO2 layer)

•  Inserted with atraumatic surgical technique that avoids overheating of bone

•  Implants must have good initial stability at the time of placement

•  Implants must not be subjected to functional forces during initial healing period

A non-loaded healing period: 1.  Anterior MN: 3 m 2.  Posterior MN: 4 m 3.  Maxilla: 6 m

Submerged & Non-loaded

Traditional Loading

Two-Stage One-Stage

Cover Screw

Stage 1 Surgery

Healing Abutment

Stage 2 Surgery

Final Restoration

Healing Abutment

Final Restoration

Maxilla: 6 months Ant MN: 3 months Post MN: 4 months

Surgical Considerations

•  Informed consent signed •  Preoperative ABx •  Chlorhexidine mouth rinse •  Standard sterile technique •  Atraumatic surgical

technique: 1.  Sharp clean incisions 2.  Appropriate flap design 3.  Sharp drills 4.  Copious irrigation 5.  Intermittent moderate

speed (<2,000 rpm) 6.  Gentle handling of tissue

H incision Flap Design ‘Papilla-sparing Incision’

Sharp Clean Incision

Surgical Considerations

•  Excessive surgical trauma and thermal injury result in osseonecrosis and fibrous encapsulation

•  Temperature over 47 °C for 1 min causes heat necrosis in bone (Eriksson & Albrektsson 1983)

•  Heat generation is affected by speed, load placed on drill, drill sharpness and design

•  Precise osteotomy preparation by surgeon to achieve good primary stability

•  Good primary closure

47 °C Precise osteotomy

preparation

Good Primary Closure

From Larry Peterson, Contemporary Oral

& Maxillofacial Surgery, 3rd Edition

Surgical Considerations

•  Primary mechanical stability is provided by implant design, bone quality & precise osteotomy preparation

•  The transition from primary mechanical stability to biologic stability takes place during early wound healing & is provided by newly formed bone

Threaded Implant

Cylinder-Type Implant Press-fit

Implant Design

Precise Osteotomy Preparation

Stage One Surgery

•  When to tap? •  When to

countersink?

• Coolant (copious irrigation) • Sharp drills • Temp over 47 °C for 1 min causes heat necrosis in bone (Eriksson & Albrektsson 1983) • Up & down motion for effective irrigation • Avoid over-torque (Implant over-tightening causes bone micro-fractures/bone necrosis)

Stage One Surgery

•  Twist drills are longer than selected implants

• Countersink only in presence of thick cortical layer

•  Excessive countersinking in poor quality bone may compromise primary stability

•  Tap only in dense bone (most implants are self tapping i.e. self threading)

•  Placement torque should not exceed 45 Ncm

Anatomical Considerations

5.0 mm

3 mm

2 mm

Mental Nerve Anterior Looping

IAN Mental Nerve

Mental Nerve exiting without Anterior Looping

Anatomical Considerations

IAN

IAN

Lingual Nerve Lingual Nerve

Heasman 1988 Rajchel et al 1986

Wilson 1989

Anatomical Considerations

Nasal Cavity & Maxillary Sinus

Anatomical Considerations Alveolar Bone Contours

Labial Concavity Lingual Concavity Lingual plate perforation

Lingual Artery: Hemorrhage Lingual Nerve: Nerve damage

How to Assess Implant Primary Stability?

1.  Resonance Frequency

Analysis (RFA)/Implant Stability Quotient (ISQ)

•  Transducer is excited over a frequency range

•  Response is measured •  RF is determined by

degree of stiffness at IBI & level of bone surrounding the implant

•  Implant stability quotient (ISQ) is a numerical value ranging from 0 – 100 reflecting the level of stability

How to Assess Implant Primary Stability?

2. Implant insertion torque

Stage Two Surgery • Implant exposure • Removal of cover screw • Selection of healing abutment: A periodontal probe determines ST thickness • Connection of healing abutment using a screw driver

Abutments emerge from ST by about 1-2 mm

Abutments have to be fully seated

Cover screw exposure

One-Stage Versus Two-Stage

Things to consider: •  Primary stability •  Interim prosthesis (can it

be modified without weakening)

•  Patient compliance •  Placement of implants &

simultaneous grafting e.g. guided bone regeneration (GBR)

Implant placed as a one-stage

Implant placed as a two-stage

One-Stage Versus Two-Stage

When to consider one-stage placement? 1.  The implant has good primary stability 2.  The interim prosthesis can be modified to

accommodate the healing abutment 3.  Implant placement is associated with no

grafting or minimal grafting

Extraction & Immediate Implant Placement

Evaluation at the time of C/S 1.  Smile line (SL)

Ø  Avoid in high SL 2.  Gingival Biotype (GB)

Ø  Avoid in thin scalloped GB as it is usually associated with thin labial bone plate

3.  Infection-free site 4.  Inflammation-free site 5.  Check radiographically for

proximity of apex of socket to vital structures e.g. IAN, Maxillary sinus &Nasal cavity Ø  Avoid if there is proximity

6.  Look for features that lead to good primary stability e.g. short and small roots, wide inter-radicular bone, small tooth size (molars vs. bicuspids vs. incisors)

Thin Scalloped Thick Blunted

Extraction & Immediate Implant Placement

Evaluation at the time of extraction

1.  Atraumatic extraction 2.  Check height & thickness

of labial or buccal plate of bone

3.  Check morphology of socket and gap between implant & socket wall (<2mm no grafting, >2mm graft)

4.  Primary stability Ø  Avoid if you cannot get

good primary stability

Thank you

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