Raju tooth and implant/ dental crown & bridge courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS
 INTRODUCTION
 STRUCTURE OF PERIODONTAL LIGAMENT
 STRUCTURE OF PERI-IMPLANT TISSUES
 CLINICAL PARAMETERS COMPARING TEETH AND
IMPLANT
 BIOMECHANICAL DIFFERENCE BETWEEN TEETH
AND IMPLANT
 CONCLUSION
 BIBLIOGRAPHY

INTRODUCTION
The primary function of a dental implant is to act as
an abutment for a prosthetic device, similar to a natural
tooth root and crown. The restoring dentist designs and
fabricates a prosthesis similar to one supported by a tooth
and as such also evaluates and treat the dental implant
similarly to a natural tooth. Yet fundamental differences in
the support system have to be recognized.

PERIODONTAL LIGAMENT
 Periodontal ligament is a
fibrous connective tissue
that is noticeably cellular
and contains numerous
blood vessels.
 Periodontal ligament
comprise cells as well as
extracellular matrix
consisting of fibers and
ground substance.

Synthetic cells
Resorptive cells
Other cells
Extracellular matrix
- fibers
- ground substances
Other structures
Functions.

PERI-IMPLANT TISSUES
 Soft tissue seal 3 mm tissue
 2 layers - epithelial
- connective
 lacks keratinization
 Increased susceptible.
 Sole vascular supply –
alveolar supraperiosteal.
 Connective tissue rich in
collagen
 Acellular and avascular.

CLINICAL PARAMETERS
1. Longevity
2. Pain
3. Mobility Vs rigid fixation
4. Percussion
5. Crestal bone loss
6. Radiographic evaluation
7. Keratinized tissue
8. Probing depths
9. Bleeding index
10.Peri-implant disease

LONGEVITY
Criteria for implant success;[Albrektsson]
1. An individual unattached implant is immobile when
tested clinically.
2. The radiograph should not demonstrate any evidence of
periimplant radiolucency.
3. Vertical bone loss is less than 0.2mm annually after the
first year of service of the implant.

4. Individual implant performance is characterized by an
absence of persistent or irreversible signs and symptoms
such as pain, infections, neuropathies, paresthesia, or
violation of the mandibular canal.
5. Success rate is a minimum of 85% for 5 years and 80%
for 10 years.

PAIN
 Subjective findings of pain, tenderness and sensitivity are
commonly seen in natural tooth.
 A natural tooth often becomes hyperemic and cold
temperature sensitive as the first indicator of the problem.
 A tooth with more serious condition becomes sensitive to
heat and painful to percussion, indicating pulpitis.

 The implants does not become hyperemic and is not
temperature sensitive, and the early warning signs and
symptoms of a problems may not be present.
 Pain is rarely associated with the implant after primary
healing.
 Percussion and forces upto 500g are used clinically to
evaluate tooth or implant pain or discomfort.
 The persistent pain during percussion or function requires
implant- removal even in the absence of mobility.

Pain in implant occurs due to :
1. Soft tissue entrapment between implant and abutment-
elimination of soft tissue.
2. Implant tenderness immediately after surgery - Implant
placed proximity to nerve – unthread the implant and
reevaluate.
3. Implant tenderness during percussion or function after
stage I healing - Bone stress beyond physiologic limits

Implant sensitivity or mild tenderness rather than
pain in a rigid implant is most unusual and signals a more
significant complication for an implant than for a tooth

MOBILITY
Rigid fixation is a clinical term that means the absence of
observed clinical mobility.
Osseointegration is a histologic term defined as bone in
direct contact with an Implant surface at the magnification
of light microscope

 Rigid fixation indicates the absence of clinical mobility of
an implant tested under forces upto 500 g.
 A non mobile Natural tooth, usually anteriors moves
around 0.1mm and molars around 56 to 73microns.
 Implant moves less than 73 microns.
 Mobility can be tested using two rigid instruments apply a
labiolingual force of approximately 500g.

Clinical implant mobility scale
Scale description
0 absence of clinical mobility
1 Slight detectable horizontal mobility
2 Moderate horizontal mobility upto 0.5mm
3 Severe horizontal movement greater than 0.5mm
4 Visible moderate to severe horizontal and any
visible vertical movement.

 Natural tooth with primary occlusal trauma exhibits an
increase in mobility and radiographic periodontal ligament
space. Once the cause of trauma is eliminated, the tooth
return to zero mobility and a normal radiographic
appearance.
 In implant, with 0.1mm horizontal mobility, on occasion
may return to rigid fixation. To achieve this, implant
should be completely out of occlusion for several months.

An osseointegrated implant with greater than 0.5 mm
horizantal mobility or any vertical mobility should be
removed to avoid continued bone loss and future
compramise of the implant site

 Periotest – is a computed mechanical device developed by
Schulte that is used to evaluate rigid fixation of implant or
prosthesis and measures the damping effect of an object.
 The recording ranges from -8 to +50.
 Teeth with zero clinical mobility have typical ranges from
+5 to +9.
 Implant corresponds to values ranging from -8 to +9.

PERCUSSION
 It is used on teeth to determine which
tooth is sensitive to function or is
beginning to abscess.
 Percussion is an indicator neither of
clinical health nor of rigid fixation

CRESTAL BONE LOSS
 Crestal bone loss area is usually a significant indicator of
implant health.
 Crestal bone loss after prosthesis delivary is a primary
indicator of the need for initial preventive theraphy.
 Adell et al, determined that successful implants after first
year loading had an average 0.1mm bone loss for each
year.

 Early loss of crestal bone beyond 1mm after prosthesis
delivery is usually a result of excessive stress at the crestal
implant-interface.
 the dentist should evaluate and reduce stress factors such as
occlusal forces, cantilever length, and especially
parafunction on observation of initial bone loss.

 Secondary bone loss around an implant is usually a
compound condition created by bacteria and increased
stress.
 When ever possible implant should be inserted at or above
the bone crest to avoid the increase in sulcus depth around
the implant related to crestal bone loss following abutment
placement.

Threaded implant pitch ( distance between the threads ) is a
known distance for each system.
Ex: 0.6 mm for branemark system.
0.4 mm for biohorizons dental implant.
It can be used as radiographic marker.

 If more than one half of implant height has lost crestal bony
contact, the implant is at significant risk and is considered a
failure, regardless of original amount of implant - bone
contact.
 If an Implant has lost 5 mm of bone and has a probing
depth of 10 mm. the situation is much worse than an
implant with 6 mm of bone loss and a 3-mm probing depth.

RADIOGRAPHIC EVALUATION
 The radiographic assessment of natural teeth assists in
determining the presence of decay, lesions of endodontic
origin and periodontal bone loss.
 Implants do not decay and do not develop endodontic
related conditions.

 The crestal bone region is often the most diagnostic for the
ranges of optimum, satisfactory, and compromised health
conditions.
 Radiographic interpretation is one of the easiest clinical
tools to use to assess implant crestal bone loss but has
many limitations.

 Crestal bone loss around the implant can be evaluated but
radiograph only illustrates clearly the mesial and distal
crestal levels of bone , but early bone loss often occurs on
the facial aspect.
 An absence of radiolucency does not mean presence of
bone at the implant interface, since 40% decrease in density
is necessary to produce a traditional radiographic
difference in this region because of the dense cortical bone.

 Parallel periapical radiographs are more difficult to obtain
for implants than for tooth.
 Crestal bone loss is evaluated best with vertical bite-wing
films or periapical radiographs that do not include the
apical portion of the implant.
 If threads are clear on one side but are fuzzy on the other
side the angulation was incorrect by 10 %.

 Periimplant radiolucency indicates the presence of
surrounding soft tissue and is a sign of implant failure.
 The cause may be from infection (bacterial), iatrogenic
(heat-induced bone loss), nonrigid fixation (iatrogenic or
patient-induced), or local bone-healing disorders.
 On rare occasion an apical radiolucency has been observed
on a nonmobile implant and is most likely a perforation of
one of the lateral cortical plates of bone but also may be
from contamination of the drill, overheating, or infection.

If bone loss greater than 2mm is observed from the bone
levels noted from stage II uncovery to the prosthesis
delivery, parafunction on the transitional prosthesis should
be suspected. Night guards and stress reduction on the
affected implants are indicated.

KERATINIZED TISSUE CONCERNS
 Lang and loe advocated a minimum of 2mm keratinized
tissue and 1mm attached gingiva to maintain gingival
health.
 Least amount of keratinized tissue is in I PM
 If all other periodontal indexes are normal, the amount or
absence of keratinized gingiva has little to do with the
expected longevity of the tooth.
 Its not mandatory but benefit if present.

 Although keratinized tissue around a tooth may not be
mandatory for long-term health, a number of benefits are
present with keratinized mucosa.
 Keratinized gingiva has more hemidesmosomes; hence the
junctional epithelial attachment zone may be of benefit in
keratinized tissue.

The orientation of collagen fibers in the connective tissue
zone of an implant often appears perpendicular to the
implant surface, whereas these fibers in mobile,
nonkeratinized tissue run parallel to the surface of the
implant.
Attached keratinised gingiva is more desirable for example
a restoration in the esthetic zone requires keratinised
mucosa to develop the soft tissue drape around the implant
crowns.

PROBING DEPTHS
 Probing depths around teeth are an excellent proven means
to assess the past and present health of natural teeth.
 Stable, rigid, fixated implants were reported with pocket
depths ranging from 2 to 6 mm
 Implant sulcus depth may be a reflection of the original soft
tissue thickness of the area before implant placement
 The correct pressure recommended for probing is 20 g,

A primary reason for the increased probing depth around
implants compared with healthy teeth is the difference in
makeup of the biological width.
the probe next to a natural tooth measures the sulcus depth
and a portion of the functional epithelial attachment.
With an implant, the probe goes beyond the sulcus, through
the junctional epithelial attachment, through the Type III
collagen connective tissues, and reaches closer to the bone.

 Sulcus depths greater than 5 to 6 mm have a greater
incidence of anaerobic bacteria
 Minor bone changes are clinically easier to observe with a
periodontal probe than with radiographs.

 Probing also reveals tissue consistency, bleeding, and
exudates.
 Material from which the probe should be fabricated.
 Scratching the surface may contribute to plaque migration
following the direction of the scratch.

BLEEDING INDEX
 Gingival bleeding when probing correlates with
Inflammation and the plaque Index
 Inflammation is typically less around implants than around
teeth
 The most common bleeding gingival index used for
implants is the Loe and Silness gingival index.

PERI-IMPLANT DISEASE
 Initial pellicle composition is similar
 They contain gram +ve bacilli and cocci.
 Gingivitis is a bacteria-induced inflammation involving the
region of the marginal gingiva above the crest of bone and
is similar in both teeth and implant- peri mucositis.

 The bacteria in gingivitis around a tooth may affect the
epithelial attachment but without loss of connective tissue
attachment. Because the connective tissue attachment of a
tooth extends an average of 1.07 mm above the crestal
bone, at least 1 mm of protective barrier above the bone is
left.

In contrast, no connective tissue attachment zone
exists around an implant because no connective
fibers extend into the implant. Hence no
connective tissue barrier exists to protect the
crestal bone around an implant.

 Periodontitis around teeth is caused by bacteria,
characterized by apical proliferation and ulceration of the
junctional epithelium, progressive loss of the connective
tissue attachment, and loss of alveolar bone.
 After prosthesis delivery, early crestal bone loss around an
implant usually is not caused by bacteria.
 However, bacteria on occasion may be the primary factor.
Anaerobic bacteria have been observed especially when
sulcus depths are greater than 5 mm.

BIOMECHANICAL DIFFERENCES
TOOTH
 Shock absorber
 Decreased stress
 Mobility to occlusal
trauma, returns after
elimination.
 Movement
8-28 microns vertical
56-108 horizontal
IMPLANT
 no resilient interface
 no force dissipation
 irreversible bone loss
 0-5 microns,
10-50microns.

Biomechanical design
 Greater width of occlusal
surface hence lesser
magnitude of stress.
 Cross section shape resists
bucco-lingual or lateral
load.
 Lesser width
 Round cross section

Sensory nerve complex
 Premature contact –
orthodontic migration.
Excess tongue/oral habits
can cause migration
 Early detection of occlusal
load. Hence bite force is
of less magnitude
 No orthodontic movement
 Biting force is 4 folds
greater due to lack of
proprioception.

 Clinical evidence of
occlusal trauma – wear
facets, stress lines,
cervical abfraction.
 Fatigue fracture.

CONCLUSION
Devan stated that preservation of that which
remains and not the meticulous replacement of what is lost.
Even though the implant has got more advantages
compared to other prosthesis, ultimately, it is the natural
tooth which remains the best.

BIBLIOGRAPHY
1. Contemporary Implant Dentistry – Carl E.Misch
2. Endosseous implants for Maxillofacial reconstruction – Block
and Kent
3. ORBANS “Oral histology & embroyology”
4. Dental implants- the art and science- Charles A.Babbush.
5. Implants and restorative dentistry- Gerard M.Scortecci.
6. Teeth and implants. British Dental journal 1999, vol 187; no 4;
page 183.
7. Dental Clinic of North America.-Implantology-July 2006;50;3.

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