Perio prostho /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


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INTRODUCTION
BASIC CONSIDERATIONS
TRAUMA FROM OCCLUSION
OCCLUSION AND ITS EFFECTS ON PERIODONTAL LIGAMENT
SPLINTING
PLACEMENT OF MARGINS OF RESTORATION
GINGIVAL RETRACTION AND IMPRESSION
CROWN CONTOURING
PRE PROSTHETIC PERIODONTAL SURGERIES
REMOVABLE PARTIAL DENTURE AND PERIODONTIUM
CONCLUSION
REFERENCES


Dentistry has progressed from the times
when a missing tooth was replaced by an
animal tooth to the present when it is being
replaced with an implant.
► We have moved into a new era in which
dentistry can no longer be practiced in
isolated specialty divisions to meet the
overall needs of the patients. The team
approach is replacing the individual
approach resulting in more effective
patient care.
►


► In the following deliberation I would like to

bring about the various periodontal aspects
to be considered in designing a prosthesis
which may be called as “Periodontal
Restorative Interrelationship


BASIC
CONSIDERATIONS
►
The periodontium
is the attachment
apparatus of the teeth
and consists of
cementum, periodontal
ligament, alveolar
bone and a portion of
the gingiva

Gingiva:
►
It is divided anatomically into marginal,
attached and interdental areas.
► The attached gingiva extends from the
mucogingival junction to the projection on the
external surface of the bottom of the gingival
sulcus.
► The width of the attached gingiva on the facial
aspect differs in different areas of the mouth. It is
generally greatest in the incisor region (3.5 to
4.5mm) and less in the posterior segments with
the least width in the first premolar area 1.9mm.

Anatomic landmarks of gingiva


► Mucogingival junction remains stationary

throughout the adult life. Width of the
attached gingiva increases with age and in
supraerupted teeth.
► Keratinized gingiva includes both the
attached gingiva as well as the marginal
gingiva.
► Clinical gingival sulcus depth normally
measures 2-3mm

Periodontal Ligament
►

It is composed of collagen
fibres arranged in bundles that
are
attached
from
the
cementum of the tooth to the
alveolar bone. In humans the
width
of
the
periodontal
ligament ranges from 0.15 to
0.38mm. Occlusal loading in
function affects the width of the
periodontal ligament. If occlusal
forces are within physiologic
limits, increased function leads
to increase in the width of the
ligament

► In single rooted teeth, the axis of rotation is

located in the area between the apical third
and middle third of the root. In multirooted
teeth, the axis of rotation is located in the
bone between the roots.
► The ligament is narrowest in the region of
axis of rotation. Due to physiologic mesial
migration, the periodontal ligament is
thinner on the mesial surface than on the
distal surface

Functions of Periodontal Ligament
►
Physical


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Resistance to impact occlusal forces.
Transmission of occlusal forces to bone.

Formative and remodeling function.
Nutritional and sensory function

Pathological deepening of gingival sulcus is termed as periodontal
pocket. It is due to the direct extension of gingivitis
into the alveolar bone

Probing
►
The thinnest probe is desired that
permits probing the depth of the pocket
without patient discomfort. While probing
the dentist must pay attention to the root
anatomy.
►
Local anesthesia is recommended when
the bony contours are probed to establish
whether surgery is necessary. This
procedure is called Bone Sounding

Mobility
►
It can be determined by holding the tooth
between the handles of two metallic instruments or
with one metallic instrument and one finger. An
effort is made to move the tooth in all directions.
Mobility is graded as:
► Grade I – Barely distinguishable tooth movement.
► Grade II – Any movement upto 1mm (Labiolingual
or mesiodistal).
► Grade III – Any movement more than 1mm or
teeth that can be depressed or rotated in their
sockets.

Trauma from occlusion
►
When the occlusal forces exceed the adaptive
capacity of the tissues, tissue injury results. The
resultant injury is termed trauma from occlusion.
►
Trauma from occlusion may be caused by
altrations in occlusal forces or reduced capacity of
the periodontium to withstand occlusal forces.
When trauma from occlusion is the result of
alterations in occlusal forces, it is called primary
trauma from occlusion . When it results from
reduced ability of the tissues to resist occlusal
forces, it is known as secondary trauma from
occlusion .

Trauma from occlusion occurs in the supporting
tissues and does not affect the gingiva.
The changes in TFO consists of
► a) increased width of periodontal ligament space,
► b) thickening of laminadura along the lateral
aspect of the root,
► c) vertical rather than horizontal destruction of
interdental septum,
► d) root resorption,
► e) radiolucence and condensation of alveolar
bone.

► Thus, in the absence of inflammation, the

response to TFO is limited to adaptation to
increased forces. In the presence of
inflammation, the changes in the shape of
the crest may be conducive to angular bone
loss with infra bony pockets. Most common
clinical sign of TFO is increased tooth
mobility

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Radiographs
The radiograph is a valuable aid in the diagnosis,
prognosis and evaluation of the treatment outcome of
periodontal disease.
The most useful technique in evaluating the tooth to bone
relationship is the long cone technique. A film positioning
holder should be used. The areas to be reviewed on the
radiographs are:
Alveolar crest resorption.
Integrity and thickness of laminadura.
Evidence of generalized horizontal bone loss.
Evidence of vertical bone loss.
Widened periodontal ligament space.
Density of the trabaculae of both the arches.
Size and shape of the roots compared to crown, to
determine crown root ratio

Occlusion and its effect on periodontium
►
The effect of occlusal forces on the
periodontium is influenced by their severity,
direction, duration and frequency. When severity
increases, the periodontal fibers thicken and
increase with the alveolar bone becoming denser.
►
Changing the direction of occlusal forces
changes the orientation of periodontal ligament
fibres. The principal fibres of the periodontal
ligament best accommodate occlusal forces along
the long axis of the tooth.
►
Lateral forces initiate bone resorption in areas
of pressure and bone formation in areas of
tension.

Occlusal Therapy as a Part of Periodontal
Treatment
►
Studies indicate that the gain in the attachment
level after periodontal therapy is inversely
proportional to the degree of mobility.
►
Occlusal therapy should be performed as a
part of periodontal treatment-whenever there is a
functional indication for it.
► A diagnosis of TFO fully justifies occlusal therapy.
► When malocclusion interferes with achievement of
stable intermaxillary relationship. E.g. Migrating
teeth, diastemas, flaring of anterior teeth.
► Bruxism may require treatment, since it is the
basis for every type of dysfunctional manifestation
and often is the first evidence of lack of adaptation
to occlusion

► Occlusal therapy is also indicated when

missing teeth need to be replaced or food
impaction needs to be corrected. Occlusal
therapy should not be initiated unless there
is evidence to indicate that the system is no
longer adapting to the occlusal scheme of
the individual


Occlusal Adjustment
► Removing occlusal prematurities in centric relation
and centric occlusion. A ‘long-centric’ or ‘freedom
in centric’ when cusp tips contact horizontal stops
in the fossae.
► Eliminating balancing interferences which will
allow the mandible to move freely laterally and
protrusively.
► Adjusting working contacts in lateral movements
and anterior contacts in protrusion. Depending on
the occlusal pattern of the individual no single
tooth should be overloaded during excursions with
either group function or a cuspid protected
occlusion.

When to perform occlusal therapy in the
sequence of periodontal treatment
►
It is preferable to postpone any procedures
related to occlusion until root preparation has been
completed and the patient has been instructed in
oral hygiene procedures. When inflammation has
been controlled, teeth will modify their position
within the socket and will be more stable and less
mobile. Thus, after controlling inflammation,
occlusal therapy is performed when indicated.

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Splinting
Splinting refers to any joining together of two
or more teeth for stabilization.
Occlusal correction and construction of an
appliance precede splinting.
Splinting has 3 purposes:
To protect loose teeth from injury during
stabilization in a favourable occlusal
relationship.
To Distribute occlusal forces for teeth
weakened by loss of periodontal support.
To prevent a natural tooth from migrating

The number of teeth required to stabilize a
loose tooth depends on:

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Degree and direction of mobility.
The remaining bone.
The location of the mobile tooth.
Whether the tooth is to be used as an abutment
tooth.


► Reducing mesiodistal mobility is easier than

reducing buccolingual mobility because of
approximating teeth that aid in support. It is
advisable to use more than one firm tooth to
stabilize a mobile tooth.
►
If the mobile teeth are splinted to
adjacent teeth without correction of the
occlusal traumatism or parafunctional
habits, the entire splint can become
unstable

Splinting methods:
It may classified as
► Temporary or reversible.
► Provisional.
► Permanent.
Some methods of reversible splinting
are ligature wire, circumferential wiring, removable
appliances and bonding. Removable appliances
include the Hawley’s Retainer and a continuous
clasp RPD. A swing-lock RPD though costly and
can be damaging is used for medically
compromised patients.

Splinting by Bonding
►
Newer materials have made splinting teeth
easier. The composite resins have greater
strength and light cured bonding permits better
control of contours. Temporary splinting is
accomplished with the composite material alone or
in combination with extracoronal or intra coronal
wires or screen meshes.
►
Permanent splinting can also be performed
with resin bonded retainers (Maryland bridges) or
bars and plates.

► Provisional

splinting with full
coverage acrylics
►
This method is commonly used with
periodontally compromised patients where
there is a commitment to fixed splints after
periodontal therapy. Before periodontal
treatment, the teeth are prepared and heat
processed acrylic treatment restorations are
constructed and cemented with sedative
cements. When the tissue has healed and
matured after surgery, cast splints are
inserted

Indications for splinting
►
Splinting is indicated if mobility is increasing
after periodontal and initial occlusal therapy and
the teeth are interfering with chewing ability and
comfort.
According to Lindhe, candidates for splinting are:
► Progressive (increasing) mobility of a tooth as a
result of gradually increasing width of the
periodontal ligament in teeth with a reduced height
of alveolar bone.
► Increased bridge mobility despite splinting.
►
Progressive mobility in situation 1 can often be
controlled by unilateral splints.
►
Situation 2 requires cross-arch splinting

► PLACEMENT

OF MARGINS OF
RESTORATION
►
Whenever possible margins are
prepared supragingivally on the enamel of
the anatomic crown. Any restorative
material is a foreign body in the gingival
sulcus and unfortunately they provide an
area favourable for plaque formation

► Advantages of supragingivaly placed

margins are:
► Favourable reaction of the gingiva.
► Wider shoulder tooth preparations can
accommodate an adequate bulk of
porcelain without-pulpal injury.
► Metal margin finishing techniques are
easier.


► Intracrevicular

Margin Placement
►
Despite the advantages of supragingival
margins there are clinical situations
requiring intracrevicular margin placement.
They are:
► Esthetics.
► Severe cervical erosion, restorations or
caries extending beyond gingival crest.
► Adequate crown retention in short or broken
down clinical crowns.
► Elimination of persistent root sensitivity.

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Intracrevicular Depth
Accurate estimate of true gingival crevice is important
to ensure that margins do not impinge on junctional
epithelium or connective tissue attachment (biologic
width ). This requires the use of an accepted periodontal
probe. Position of the probe and probing force are critical
for accuracy.
In health, the probe is stopped by the junctional
epithelium, whereas gingivitis allows penetration of
junctional epithelium and connective tissue fibres.
Studies have estimated that the ideal intracrevicular
depth for margins is 0.5-1mm beneath gingival crest and
not more than 0.5mm when the crevice is adjacent to root
surfaces


► Studies have also demonstrated that a space of

2mm is needed for supracrestal connective tissue
attachment and junctional epithelium to attach to
the tooth. This 2mm band is a physiologic
dimension that is required around every tooth in
the mouth. It has been called as biologic width. If
the restoration infringes on this width, there is no
place for attachment apparatus to insert. An
inflammatory response results, attachment loss
with apical migration occurs and pocket formation
ensues

Gingival Retraction and Impressions
►
All retraction methods induce transient trauma
to the junctional epithelium and connective tissue
of gingival sulcus.
► Retraction chord: It usually produces limited
gingival recession and can protect the sulcular
tissues during preparation. If used carelessly when
inadequate attached gingiva is present, injury to
gingival fibres occurs. This can allow the
impression material to be forced into the gingival
connective tissue and bone producing a foreign
body reaction.

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Electrosurgery : They have certain limitations.
But when used properly the cellular healing is
comparable to a scalpel cut. Controlled depth
cutting electrode tips avoid bone trauma but
injure the gingival fibres, if the tip is not angled
properly in the sulcus. Oringer’s solution or
surgical pack may enhance healing.
In patients with thin covering of gingiva and
alveolar bone over the root, electrosurgery
should not be used as the loss of tissue from the
internal or crevicular surface can result in
gingival recession. In these patients, the gingiva
should be retracted with retraction chords.

TEMPORARY AND PROVISIONAL
CROWNS
►
Improperly constructed “interim” restorations
may cause periodontal inflammation and gingival
recession. The requirements for fit, polish and
contour in the interim restoration should be the
same as for the final restoration.
►
Long-term restorations should not be called as
temporary but should be regarded as provisional
or treatment restorations. These allow the dentist
to assess the effect of final restoration

EMBRASURES
►
When teeth are in proximal contact, the spaces
that widen out from the contact are known as
embrasures. Each interdental space has 4
embrasures.
► An occlusal or incisal embrasure that is coronal to
the contact area.
► A facial embrasure.
► A lingual embrasure.
► A gingival embrasure which is the space between
the contact area and the alveolar bone.

In health, the gingival embrasure is filled with
soft tissue, but periodontal diseases may
result in attachment loss creating open
gingival embrasures.
► The gingival embrasure : From a
periodontal view point, the gingival
embrasure is the most significant


► Periodontal diseases cause tissue destruction,

which reduces the level of alveolar bone,
increases the size of the gingival embrasure and
creates an open interdental space. Restorations
may be constructed to preserve the morphologic
features of the crown and root and retain the
enlarged embrasure space or when esthetic
situations dictate, the teeth may be reshaped by
the restorations so that the gingival embrasures
are relocated close to the new level of the gingiva.
►
To relocate the gingival embrasure, the dentist
changes the contour of the proximal surfaces and
broadens the contact areas more apically.

► In fixed prosthesis and / or multiunit fixed splints,

the interproximal contact and / or soldered joint is
frequently carried for too apically so that it
invades the embrasure space from its coronal
aspect. This leads to inflammation and destruction
of periodontal tissues.
►
The responsibility of determining the size of
the interproximal contact should rest with the
dentist, not the technician.

► CROWN

CONTOUR
►
The contours of full and partial coverage
restorations play a supportive role in
establishing a favourable periodontal
climate. The theories of crown contouring
that have evolved are:
► Gingival protection.
► Gingival stimulation.
► Muscle action.
► Access for oral hygiene.

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Gingival Protection Theory:

It advocates that contours of cast restorations
be designed to protect the marginal gingiva from
mechanical injury. In 1962 this concept was
challenged by Morris who reported that the
response of gingival tissue around teeth
prepared for complete artificial crowns but which
had lost their temporary crowns were similar to
the adjacent unprepared teeth. Schluger stated
that the so called protective cervical bulge
protects nothing but the microbial plaque


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Gingival stimulation theory:

This concept reasons that as food is
masticated, it will pass over the gingiva
stimulating it and causing increased
keratinization of the epithelium. Keratinized
epithelium would be more resistant to
periodontal breakdown. Several authors have
shown that the gingival margin is not in the path
of masticated food. Even if the food passing over
the teeth were to increase keratinization, this
stimulating would occur at the buccal and lingual
surfaces

Muscle action theory:
►

This theory advocates that the perioral
musculature (tongue, cheeks) are
responsible for maintaining a healthy
periodontal environment. They suggest
that overcontouring prevents normal
cleansing action by the musculature and
allows food to stagnate in the
overprotected sulcus


Theory of access for oral hygiene
►

This theory is based on the concept that
the prime etiologic factor in caries and
gingivitis is plaque. Thus, crown contour
should facilitate plaque removal, not hinder
it.


Four guidelines to contouring crowns are:
Buccal and lingual contours – flat, not fat
►
Plaque retention on the buccal and lingual
surfaces occurs primarily at the infrabulge of the
tooth. Reduction or elimination of infrabulge would
reduce plaque retention.
Open embrasures
►
Every effort must be made to allow easy
access to interproximal area for plaque control. An
over contoured embrasure will reduce the space
intended for the gingival papilla.

Location of contacts
►
Contacts should be directed incisally or
occlusally and buccally in relation to the central
fossa, except between maxillary first and second
molars. This creates a large lingual embrasure
space for optimum health of lingual papilla.
Furcation involvement
► Furcations that have been exposed owing to loss
of periodontal attachment should be ‘fluted’ or
‘barreled out’. It is based on the concept of
eliminating plaque traps

► Facial

and Lingual sulcular contours
►
In the patient whose gingival margins are
apical to the CEJ the sulcular morphology differs
from that of a healthy patients whose gingival
margins are on enamel.
►
The intracrevicular contours of an artificial
crown should be as close to the original enamel
contour as possible. Wagman has estimated the
angle of enamel flare from CEJ to be
approximately 22.5 degrees from the vertical axis
of gingival housing.

PONTIC DESIGN
A pontic should meet the following
requirements.
► Be esthetically acceptable.
► Provide occlusal relationships that are
favourable to abutment teeth.
► Restore the masticatory effectiveness.
► Be designed to minimize accumulation of
irritating dental plaque and food debris.
► Provide embrasures for passage of food

► The health of the tissues around the fixed

prosthesis depends primarily on the patients
oral hygiene. The material with which
pontics are constructed make little
difference and pontic design is important
only to the extent that it enables the patient
to keep the area clean.


CEMENTATION
►
During cementation it is important that the
restoration be seated as close to the tooth
preparation as possible. A minimal cement line at
the margin reduces plaque formation. It is
extremely important that all excess cement be
removed from the sulcus after cementation.
Removal of cement from the interproximal joints
can be facilitated by lightly coating the exterior
surfaces of the prosthesis with petroleum jelly prior
to cementation

► RESTORATION

OF MOLAR TEETH
WITH FURCATION INVASIONS
►
In long-term studies of tooth longevity,
molars are the teeth that are most often lost.
This is due to the complex root anatomy
and furcation that make periodontal therapy
and plaque control difficult for the patients


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Classification of furcation involvement
Grade I – Incipient or early lesion. Radiographic changes
not seen.
Grade II – Bone is destroyed on one or more aspects of the
furcation, but a portion of alveolar bone and periodontal
ligament remains intact, permitting only partial penetration
of probe into the furcation.
Grade III – Interradicular bone is completely destroyed, but
facial or lingual orifices of the furcation are occluded by
gingival tissue.
Grade IV – Interradicular bone is completely destroyed and
gingival tissue is also receded apically so that the furcation
opening is clinically visible

Glickman (1958)


If a full coverage restoration is indicated on a
Grade I or early Grade II furcation involved
teeth, the principles are same as that for a
normal tooth except that the preparation has
to be fluted or barreled into anatomic
depressions


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RESTORATION OF ROOT RESECTED MOLARS
Root amputation :
Removal of a root from a
multirooted teeth.
Root resection : Surgical removal of a root after
endodontic treatment.
Hemisection :
Surgical separation of a multirooted tooth
through the furcation area in such a way that a root or roots
may be surgically removed along with associated portion of
the crown.
Bisection :
Splitting and retaining the roots and
accompanying crowns of a mandibular molar or any two
roots of maxillary molar

Indications for Root resection or
Hemisection
► Vertical bone loss around one root but not others.

Post surgical healing : It is critical when
intracrevicular margins have to be placed on
resected or hemisectioned teeth. A minimum of 4
to 6 weeks of healing after surgery is required
before the soft tissues can resist the trauma of
tooth preparation

Post and cores
►
Brittleness of the pulpless root resected tooth
is the primary reason for root fractures over time.
Complete coverage of root resected teeth is
recommended especially over resection area.
►
There is no evidence that post and cores are
beneficial in resected teeth and infact they can be
detrimental. If a post and core is required because
of a coronal damage, a custom cast dowel core is
preferable to prefabricated dowel

Crown Preparation
►
Intracrevicular margins are usually required to
cover portions of root-resected area. The crown
margin should be apical to the pulp chamber or
root canal that was exposed by resection.
►
To preserve remaining tooth structure and
encourage a better fitting restoration a chamfer
finish line is recommended.
►
The gingival third of the restoration is
fabricated with a flat emergence profile from the
gingiva to facilitate oral hygiene

PRE-PROSTHETIC
PERIODONTAL SURGERY


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Mucogingival surgery
Teeth with subgingival restorations and narrow
zones of keratinized gingiva have higher
gingival inflammation scores than teeth with
similar restorations and wide-zones of attached
gingiva.
Coverage of denuded roots is also another
objective of mucogingival surgery.
Mucogingival surgery can also create some
vestibular depth when it is lacking.
Techniques for increasing attached gingiva .
Free gingival autografts.
Apical displacement flap

► When there is a pocket formation, thick

manageable pocket walls can be used for
an apically displaced flap – this flap should
be the first choice.
►
When the pockets are absent and there
is a need for increasing width of attached
gingiva, free gingival graft is the technique
of choice.

Root coverage : Two techniques are recommended.
►
Langer’s technique – use a connective tissue
graft under a partial thickness flap.
►
Tarnow technique – Semilunar coronally
displaced flap.
Langer’s technique is an excellent solution in
most of the cases, but Tarnow’s technique is
the first choice in isolated upper teeth.


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Crown lengthening procedures
In situations in which a tooth has a short clinical crown
that is deemed inadequate for the retention of a
required cast restoration, it is necessary to increase the
size of the clinical crown using periodontal surgical
procedures. By definition, the clinical crown is that
portion of the tooth that is coronal to the alveolar crest.
Therefore, to lengthen it bone margin has to be
remodeled. This is done with an apically displaced flap
and ostectomy. The removal of bone is usually not
necessary all around the tooth but if undertaken should
be done with great caution. It is essential that there be
atleast 2mm of connective tissue attachment between
the most apical extension of the restoration margin and
alveolar bone crest.

►

Ridge Augmentation procedures
Aimed at correcting the excessive loss of
alveolar bone that sometimes occurs in
the anterior region as a consequence of
advanced periodontal disease. The
excessive bone loss may create a difficult
esthetic problem and complicate
prosthetic reconstruction

Several prosthetic solutions have been
proposed:
 Placement of a thick mucosal autograft obtained
from palate or tuberosity.
 Placement of non-porous dense hydroxyapatite
under a split thickness flap or a pouch created
under a full thickness flap.
► A double flap technique used in conjunction

with hydroxyapatite


►REMOVABLE

PARTIAL
DENTURES AND THE
PERIODONTIUM


► From the periodontal viewpoint, fixed

prosthesis are the restorations of choice for
replacement of missing teeth, but there are
some clinical situations in which removable
partial prosthesis are the only possible way
to restore the lost function of the dentition.
►
It is unwise consider a removable partial
denture in patients whose oral hygiene is
inadequate

DESIGN
►
Every effort must be made to retain posterior
teeth for the distal support of edentulous areas.
When posterior teeth cannot be retained, the
design for removable partial prosthesis becomes
challenging.
Clasps:
►
Studies have shown that I-bar type of clasps
have little or no detrimental effect of periodontal
health. This design utilizes a gingivally approach
clasp, mesially positioned occlusal rest and a
proximal plate.
►
Clasps should be passive and exert no force
on teeth when the partial denture is at rest.

Occlusal rests :
► They should be designed so that the
occlusal forces are directed along the
vertical axis of the tooth. The angle formed
by the occlusal rest and the vertical minor
connector should be less than 90°. Only this
way can the occlusal forces be directed
along the long axis of the abutment tooth.


Combined Fixed and Removable
prosthesis
►
Isolated teeth with reduced periodontal support
are particularly vulnerable to periodontal injury and
loosening when used as abutments in removable
partial prosthesis. The isolated teeth should be
joined to their nearest neighbours with a fixed
prosthesis and then can be used as abutments for
removable prosthesis

Major connectors :
► They should not
impinge on the free
gingival margins. The
major connector
should be placed 6mm
away from the gingival
margin


► When periodontally compromised

mandibular anterior teeth require
stabilization, a special design of major
connector should be used for splinting teeth
together. A lingual plate should extend to
the middle third of the surface of the
mandibular anterior teeth and the coronal
border should follow the natural curvature of
the supracingula surface

OVERDENTURES
Over dentures have three obvious
advantages
► Increased retention and stability of record
base.
► Proprioception is dramatically improved
compared to a patient with complete
dentures.
► Reduction of stresses to the edentulous
ridges resulting in less bone resorption over
time

► It is important that appropriate periodontal

considerations be a part of the treatment
planning process.

 Presence of adequate zone of attached gingiva
is of critical importance around the abutment
teeth.

► Any remaining periodontal defects must be

treated in the same way as they would be
around any periodontally involved tooth
prior to fixed restoration

► One great advantage that the overdenture

concept has for periodontally involved teeth
is that it is possible to improve the crown
root ratio dramatically. This results in a great
diminution of forces applied to the remaining
root


Implant supported restorations
The main principles that determine success or
failure from a periodontal view point for an implant
supported restoration are:
► Patient selection.
► Investing tissues.
► Force distribution
Investing tissues can be defined as including
both hard and soft tissue. Both the bone height
and width must be adequate for implant
placement. In partially edentulous patients it has
been observed that keratinized tissue around
implants offer the greatest resistance to periimplant infection.

Force distribution
► Crown implant ratio – This is very important
in the presence of lateral forces. Lateral
forces result in a moment of the force on the
implant and an increase in horizontal
stresses. Implants placed in the anterior
maxilla experience more frequent
complications because of lateral stresses.
►
The greater the crown-implant ratio, the
greater the moment of force under lateral
loads

Other factors to be considered are:
► Bilateral simultaneous contact is mandatory.
► Occlusal vertical dimension must be in
harmony with the patient’s muscular
system.
► All interferences must be eliminated


► Centric vertical contacts should be aligned

with the long axis of the implant whenever
possible.
► Posterior occlusal tables may be narrowed
in order to prevent inadvertent lateral forces.
► Enameloplasty of the cusp tips of the
opposing natural teeth is indicated to help
improve to direction of vertical forces

SUMMARY AND CONCLUSION
One of the primary goals of restorative therapy is to
establish a physiologic periodontal climate and
facilitate the maintenance of periodontal health.
Traumatic occlusal relationships should be eliminated
before restorative procedures are begun and
restorations should be constructed in conformity with
the newly established occlusal patterns. If this is not
done the prostheis will perpetuate occlusal
relationship injurious to the periodontium. Subgingival
margins should be avoided as far as possible except
in cases of caries, extending apically, short crowns
hence to obtain retention, and in labial surfaces of
anterior maxillary teeth in patients who demand for
esthetics as a primary criteria.

In impression making, ginival retraction methods
should be followed deligently keeping the ginival
health in mind. All interim restorations should be so
constructed that they cause no trauma to the gingival
during the time they are in the mouth. The teeth
should taper away from their proximal contacts to get
good healthy embrasures. Over contouring of the
facial and lingual surfaces should be avoided. Over
contouring in gingival third causes plaque
accumulation and gingival inflammation. Pontic design
greatly influences gingival health. If esthetics is a
primary concern a spheriodal Pontic for the posteriors
and a modified ridge lap for the anteriors is ideal.

The occlusal surfaces should be designed to
direct masticatory forces along the long axis of
the tooth. The occlusal table should not be too
wide to prevent undue pressure on the
periodontium of the abutment teeth. A sanitary
Pontic is the periodontium’s best friend. Lastly
the surface of restorations should be as smooth
as possible to limit plaque accumulation. But
eventually after taking all these precautions,
patient education and motivation towards
plaque control and healthy oral habits is the
secret of every treatment success.

REFERENCES
1. Gengers, Snack, Vagels - Over containing in resin bonded
prosthesis Plague accumulation and gingival health J.P.D.
59:17:Jan 88.
2. Cuetis Becker, Wayne Kaldaht: Current theories of crown
contour margin placement and pontic design J.P.D. 45:268:1981.
3. Dayton K Periodontal considerations for prosthetic patients
J.P.D. 30:15:July73.
4. DominickC.L. Effect of artificial crown margin extensions and
tooth brushing frequency on gingival pocket depth.
5. David Koth: Full crown preparation and gingival inflammation
in a controlled population.
J.P.D. 48:681:1982.
6. Edmand C: Tissue response to fixed partial denture
prosthesis. J.P.D. 23:407:1970.
7. Francisco P. John pedar, Periodontal relationship and F.P.D.
J.P.D. 387:36:1976.

8. James Marcum: The effect of crown marginal depth upon
gingival tissues J.P.D. 17:479:1967.
9. Jon Ruel, Peter S., Keneth M: Effect of retraction procedures
on periodontium in humans J.P.D. 44:508:1980.
10. John Lorensonl6, Micheal N. Gingival enhancement in
F.P.D. 65:100-107:1991.
11. Joseph Clayton: Roughness of pontic materials and dental
plague - J.P.D. 23:407:1970.
12. Lee M. Jamson,William M: Crown contains and gingival
response J.P.D. 47:620:1982.
13. Martin Bermar. The complete coverage restoration and the
gingival sulcus - J.P.D.: 29:301:1973.
14. Martin Frelich, Lasy c.: F.P.D. supported by periodontally
compromised teeth - J.P.D.65:607:1991.
15. Martin Frelich, C. Riekrash: Periodontal effects of F.P.D.
retainer margins: configurment and location J.P.D.
67:184:1992.

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