Health Status for Dental Implants

Health Status for Dental Implants - costofdentalimplant.com

Health Status for Dental Implants – costofdentalimplant.com

Health Scale for Dental Implants according to International Congress of Oral Implantologists

Implant Quality Scale Group Clinical Conditions
Success (optimum health) a) No pain or tenderness upon function.
b) 0 mobility
c) <2 mm radiographic bone loss from initial surgery.
d) no exudates history.
Satisfactory survival a) No pain on function.
b) 0 mobility.
c) 2-4 mm radigraphic bone loss.
d) No exudates history.
Compromised survival a) May have sensitivity.
b) No mobility.
c) Radiographic bone loss >4 mm (less than 1/2 of implant body)
d) Probing depth > 7 mm
e) May have exudates history.
Failure (clinical or absolute failure) Any of the following:
a) Pain on function.
b) Mobility.
c) Radiographic bone loss > 1/2 length of implant.
d) Uncontrolled exudate.
e) No longer in mouth.

Reference
International Congress of Oral Implantologists, Pisa, Italy Conference 2007

Key Factors for Osseointegration

Osseointegration is defined as a direct bone anchorage to an implant body which can provide a foundation to support a prosthesis. There are many factors that influence osseointegration. Among the key factors for successful osseintegration of dental implants are: characteristics of implant material, design of the implant fixture, prevention of excessive heat during implantation etc.

The first factor pertains to characteristics of implant material. In titanium implant, an oxied layer forms when it comes into contact with the atmosphere. When the fixture has osseointegrated, this oxied layer is surrounded by a glycoprotein layer then a calcified layer.

The 2nd factor is the design of the implant fixture. The implant fixture has a threaded surface. The threads create a larger surface area. They also balance the force distribution into surrounding bone. The treads also play a role in initial implant fixation.

The 3rd factor for successful osseointegration is the prevention of excessive heat during implantation. Ideally, heat during drilling procedures should not exceed 39 C.The maximum speed during drilling should be under 2,000 r.p.m. Tapping for threading and fixture intallation should be between 15-20 r.p.m.

The 4th factor pertains pertains to “No loading while healing”. It is required that the implant fixtures left undisturbed for 6 months in maxilla and 3-4 months in the mandible.

The tapping procedure for threading and fixture installation into bone requires a drilling speed between 15-20 r.p.m. -  costofdentalimplant.com

The tapping procedure for threading and fixture installation into bone requires a drilling speed between 15-20 r.p.m. – costofdentalimplant.com

Implant Supported Denture

The denture supported by osseointegrated implants is connected to abutments by gold screws. If the denture was damaged and required repair, it could be removed by unsrewing the gold screws. If a single implant fixture failed to osseointegrate and was not able to withstand occlusal forces due to soft tissue formation, the denture could be removed to gain surgical access to the fixture site.

The denture could be maintained and supported by the remaining fixtures. At a later time, another fixture could be placed and may require fabrication of new denture. This kind of dental implant system allow retrievability which is convenient for dental implant maintenance. A lot of patients express strong desire for a fixed type denture and the fully bone anchored denture could be the treatment of choice in implant dentistry.

Implant Supported Fixed Bridges

Implant Supported Fixed Bridges

Study Casts

In implant dentistry, study casts, a facebow transfer and occlusal registration are essential for treatment planning. The study casts are important for studying the remaining teeth and residual bone and for analyzing the maxillomandibular relationship. The mounted casts can be helpful to the surgeon for implant fixture placement. Angle Class II and Class III situations are more easily evaluated from a centric relation record on the articulator. The directions for mandibular fixture placement can be estimated. In the Angle Class II or III situation, the fixture is situation, the fixture is angled toward the maxillary teeth or risidual ridge. This helps prevent prosthetic problem when fabricating the denture for proper esthetics and function.

A diagnostic wax up can also be done on the study casts or their duplicate. Proposed fixture installation sites can be checked on the study casts for proper alignment, direction, location and relation to the remaining teeth. Diagnostic wax up helps to determine the esthetic placement of teeth and potential functional speech disturbances.

Osseointegration

Dental implant fixtures under occlusal loads are surrounded by cortical and spongy bone. When osseointegration is commenced and the denture is designed for good stress distribution, cortical bone forms along the implant fixture surface a few millimeters in thickness. The cortical bone to implant surface interface has canaliculi participating in electrolyte transportation near the oxide layer. A network of collagen fibers bundles surround the osteocytes and insert into a glycoprotein layer. The haversian bone is well organized and forms osteon.

Osseointegration in spongy bone occurs as bone trabeculae approach the implant and come into intimate contact with the oxide layer. Blood vessels providing nutrition and bone remodelling occur at the bone trabeculae and surround the fixture surface. Fibroblasts and osteoblasts increase in number and change shape when closer to the implant surface then attach to the oxide layer.

Ground substance forms and fills spaces between bone trabeculae. It fuses with the oxide layer.

Osseointegrated implants

Osseointegrated implants

Destruction of Osseointegration

Bone resorption will occur at sites of inflammation or prolonged excessive stimulation. The main contributing factors to bone resorption are local inflammation from plaque accumulation and trauma from occlusion. Periodontal disease from plaque inflammatory response, and subsequent bone resorption can result from the following:

  • Direct action of plaque products on bone progenitor cells induce their differentiation into osteoclasts.
  • Plaque products directly on bone, destroying it through a non cellular mechanism.
  • Plaque products stimulate gingival cells, causing them to release mediators which in turn induce bone progenitor cells to differentiate in osteoclasts.
  • Plaque products cause gingival cells to release agents that can act as cofactors in bone resorption.
  • Plaque products cause gingival cells to release agents that destroy bone by direct chemical action without osteoclasts.
Resorbable Tissue Replacement (RTR) mixed with patient's blood

Resorbable Tissue Replacement (RTR) mixed with patient’s blood

Placement of Dental Implant or RCT

Extraction and placement of implant to replace endodontically compromised teeth has become common in recent years. It is an important option in cases of severely damaged teeth with hopeless prognosis.

Root canal treatment represents a very realistic opportunity to restore most teeth with infected pulp. Dental implants must not be misused because an RCT may appear complicated. Root canal treatment has reached a level of sophistication in recent years that clinicians with proper training can carry out RCT with high rate of success.

Placement of a dental implant.

Placement of a dental implant.

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Loose / mobile dental implants

When the dentist is faced with a mobile dental implant, a complete examination of the dental implant and its components should be undertaken. Mobility could be caused at different levels as follows.

Mobility at the fixture level
It is usually a case of failing osseointegration. It is also possible (but less likely) that there’s a fracture of the implant fixture.

Mobility at the abutment level
Abutment could become mobile if the abutment screw is loosened.

Mobility at the crown level
The crown component (prosthetic component) could become loose if it is decemented or the retention screw becomes loose.

Parts of a Branemark Dental Implant


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