Implant Dentistry

RAKESH CHANDRAN

What is a dental implant?An artificial titanium fixture placed surgically into the jaw bone to substitute for a missing tooth and its root(s).

What is dental implantology/ implant dentistry?Dental implantology is the field of dentistry that is concerned with the replacement of missing teeth and their supporting structures with artificial prostheses anchored to the jawbone.

Parallel sided and tapered, threaded screw shaped (root form), endosseous implants are most commonly used. The lecture will focus on only this type of implant

Types of dental implants

Sub-periosteal implant

Types of dental implants- not commonly used

Ramus-frame implant

Plate-form implant

Transosseous implant

• Great majority of modern root form dental implants are “threaded” in design although the thread pitch or profile can vary significantly between manufacturers.

• Implant surfaces also show variations. Surface hydrophilicity enhances adherence of biomolecules and promotes the initiation of the osseointegration process.

• Almost all modern implants today have a microporous (rough) surface rather than a relatively smooth machined surface. Roughness increases the surface area available for more “bone-implant contact”.

Implant Design

• There are more than 150 companies that produce implant components. The most established and well-known implant companies are Straumann and Nobel Biocare.

• Some of the implants available in South Africa• Straumann• Nobel biocare• Southern implants• Megagen• Dentsply implants• MIS implants• ADIN implants

Implant manufacturers

Tissue level parallel sided

Tissue leveltapered

Bone leveltapered

Bone levelparallel sided

Tissue level vs bone level implants*

• Implants that are designed to placed with the smooth (polished) collar above the bone and at the level of the soft tissue are known as “tissue level implants”

• Implants that are fully inserted within the alveolar bone are known as “bone-level implants”.

Length of an implant

• The lengths of the implant may vary between manufacturers.

Diameter of an implant

• The diameter of the implant may vary between manufacturers.

Describing an implant

For example, the implant on the left can be described as a Straumann (make), 12mm length, 4.1mm diameter, bone level implant.

• An implant can be described based on the make, the length, the diameter and whether it is bone level or tissue level implant.

Cement retained restoration1. crown2. internal screw3. abutment4. implant

Implant restorations can be screw-retained or cement retained

Implant restorations

Different types of implant designs and surface characteristics

Barfeie et al 2015. Implant surface characteristics and their effect on osseointegration. BDJ

Comparison of tooth and implant support structures*

Comparison of tooth and implant support structures*

Structure Tooth Implant

Connection Periodontal attachment Osseointegration

Junctional epithelium Hemidesmosomes and basal lamina Hemidesmosomes and basal lamina

Connective tissue Thirteen groups: perpendicular to tooth surfaces↓ Collagen ↑ Fibroblasts

Only two groups: parallel and circular fibersNo attachment to implant surface and bone↑ Collagen ↓ Fibroblasts

Biological width 2.04 to 2.91mm 3.08mm

Vascularity Greater, supraperiosteal and periodontal ligament

Less, periosteal

Probing depth 3mm in health 2,5 to 5.0mm (depending on soft tissue depth)

Bleeding on probing More reliable Less reliable

Clinical comparison of teeth and implants*

• The vascular supply of the periimplant gingival or alveolar mucosa may be limited, as compared to periodontal gingiva, due to the lack of a periodontal ligament. This may render the periimplant tissues to be more prone to infection.

• Implants cannot intrude or migrate to compensate for the presence of a premature occlusal contact (as teeth can).

• The absence of a periodontal ligament around implants reduces tactile sensitivity and reflex function.

• No treatment• A denture• A bridge • Implant treatment

Options of treatment for tooth loss

• Restore dental aesthetics• Restore lost dental function:

- Chewing- Speech

• Space maintenance and occlusal stability• Orthodontic anchorage• Convenience and comfort• Bone preservation and prevention of disuse atrophy after tooth loss

What are the indications for dental implant treatment?*

ABSOLUTE CONTRAINDICATIONSImplants cannot be placed in these situations:

Heart:• Heart diseases affecting the valves (valvulopathy)• Recent infarcts • Severe cardiac insufficiency, cardiomyopathy

Miscellaneous:• Active cancer, certain bone diseases (osteomalacia, Paget’s disease, brittle bones

syndrome, etc.),• Certain immunological diseases, immunosuppressant treatments, clinical AIDS,

awaiting an organ transplant,• Certain mental diseases,• Strongly irradiated jaw bones (radiotherapy treatment)

Age:• Children: not before the jaw bones have stopped growing (in general 17-18 years).

Contraindications for implant treatment*

Host (patient) risk factors can be local and systemic:• Systemic disease (eg uncontrolled diabetes, immunosuppression or certain medication

like bisphosphonates)• Local: radiotherapy, smoking, poor bone quality and density, periodontal disease,

occlusal trauma, parafunctional habits and bruxism, endodontic/ periapical lesions in adjacent teeth, unfavourable smile line, unrealistic patient expectations and poor soft tissue biotype etc.

Risk factors for implant placement*

Advantages• implants do not involve preparation of the adjacent teeth • implants preserve the residual bone

Disadvantages• implant treatment can be expensive• the patient requires surgery• time consuming• technically complex.

What are the advantages & disadvantages of implant over conventional treatment?*

• Good-quality clinical photography showing all standard views and site-specific views• Two sets of study casts, one untouched and one used for planning• A realistic tooth wax up or setup based on the above decision. At this point it will be

possible to see whether the definitive restoration is likely to be fixed or removable.• Construction of a radiographic stent based on the tooth setup above with radiopaque

markers that will show up on a CT scan• A sectional or full arch scan as appropriate using modern cone beam CT (CBCT)• Analysis with suitable planning software to allow a realistic three-dimensional plan of

implant and restorative component positions. • A decision as to whether sufficient bone exists and whether more advanced surgical

procedures will be required to provide bone volume

Special Investigations

• Ridge relationship• Attached tissue• Interarch clearance• Inferior alveolar nerve• Maxillary sinus• Floor of the nose

Anatomic Considerations

• Surgical- placement of the implant• Prosthetic- restoration of the implant

Procedure

Timing of implant placement*

Type 1 Immediatethe implant is placed immediately following the extraction of

a tooth

Type 2Early

(4-6 weeks)

the implant is placed in a site where the soft tissues have

healed and mucosa is covering the socket entrance

Type 3Early

(3-4 months)

the implant is placed in an extraction site at which substantial

amounts of new bone have formed in the socket

Type 4Late

(>4 months)the implant is placed in a fully healed ridge

Hammerle et al., 2004. Consensus Statements and Recommended Clinical Procedures Regarding the Placement of Implants in Extraction Sockets. Int J Oral Maxillof Implants.

Bone graftsA bone graft in implant dentistry is a surgical procedure for augmenting a deficient alveolar ridge.

Sinus floor elevationMaxillary sinus floor augmentation (also termed sinus lift, sinus graft, sinus augmentation) is a surgical procedure which aims to increase the amount of bone in the posterior maxilla (upper jaw bone), in the area of the premolar and molar teeth, by lifting the lower Schneiderian membrane (sinus membrane) and placing a bone graft.

Complementary procedures

One-stage surgery with the implant designed so that the coronal portion of the implant extends through the gingiva.

One stage vs two stage procedure*

In the two-stage surgery, top of the implant is completely submerged under gingiva.

• In the one-stage approach, the implant or the abutment emerges through the mucoperiosteum/gingival tissue at the time of implant placement, whereas in the two-stage approach, the top of the implant and cover screw are completely covered with the flap closure.

• In two-stage implant surgery, the implant must be surgically exposed following a healing period.

• The two-stage, submerged approach is advantageous for situations that require simultaneous bone augmentation procedures at the time of implant placement because membranes can be submerged, which will minimize postoperative exposure.

One stage vs two stage procedure*

LoadAny external mechanical force applied to a prosthesis, dental implant, abutment, tooth, skeletal organ, or tissue.

LoadingApplication of a force directly or indirectly onto a dental implant, tooth, or prosthesis.

Immediate occlusal loadingA clinical protocol for the placement and applying force on dental implants, with afixed or removable restoration, at the same clinical visit.

Early loadingRefers to the time of applying occlusal forces to a dental implant after its initial placement. A prosthesis is attached to the implant(s), earlier than a more conventional healing period.

Delayed loadingRefers to the time of applying occlusal forces to a dental implant after its initial placement. A prosthesis is attached or secured after a conventional healing period.

Loading of an implant

Surgical Complications• Hemorrhage and Hematoma• Neurosensory Disturbances• Implant Malposition

Biologic Complications• Inflammation and Proliferation• Dehiscence and Recession• Periimplantitis and Bone Loss• Implant Loss or Failure

Prosthetic or Mechanical Complications• Screw Loosening and Fracture• Implant Fracture• Fracture of Restorative Materials

Complications

• Infection• Bleeding• Pain• Swelling and bruising• Suture granuloma• Wound dehiscence and break down• Membrane exposures• Altered sensation or numbness to teeth, gum, lip etc.• Devitalisation of adjacent teeth

Post-operative complications to look for:

• This can occur as a result of implant placement in close proximity of the inferior alveolar nerve and particularly in case of poor surgical planning and/or technique. Any report of paraesthesia or altered sensation occurring to the teeth, lip or the gum should be investigated urgently and the signs and symptoms should be recorded. Early referral to an oral surgeon would be an advantage.

• Signs and symptoms of nerve injury:• Pain• Numbness or tingly sensation

Damage to Inferior Alveolar Nerve

• Peri-implant disease refers to the pathological inflammatory changes that take place in the tissues surrounding a load bearing implant.

• Peri-implant disease presents in two forms: peri-implant mucositis and peri-implantitis.

• Peri-implant mucositis is a disease in which the presence of inflammation is confined to the soft tissues surrounding a dental implant with no signs of loss of supporting bone following initial bone remodeling during healing.

• Peri-implantitis is defined as an inflammatory process which affects the tissues around an osseointegrated implant in function, resulting in the loss of supporting bone, which is often associated with bleeding, suppuration, increased probing depth, mobility and radiographical bone loss.

Peri-implant mucositis and peri-implantitis*

Peri-implant mucositis

Peri-implantitis

• Success means that an implant is present at the time of review and fulfils certain pre-established criteria such as no pain, radiolucency, no bone loss, no peri-implant pocketing etc.

• Survival means that, at the time of examination, the implant is simply present in situ but the condition of the implant is not taken into consideration. In other words, survival rates do not take in to account whether or not there are any problems with the implant such as crestal bone loss or deep pocketing. Survival rates of dental implants have been reported to be in excess of 90% after 15 years.

Success and survival of dental implants*

Structured courses offered in South Africa• Postgraduate Certificate Course/ Diploma in Oral Implantology offered by the

University of Pretoria.• Implant & Aesthetic Academy, Cape Town• Diploma in Oral Implantology, University of Western Cape

Online education• International Team for Implantology (www.iti.org)• Foundation for oral rehabilitation (www.for.org)• Dental Campus (www.dental-campus.com)• Dental XP (www.dentalxp.com)

Furthering your education in implant dentistry

Thank you for your attention