Diagnosis and treatment planning in implants 2. /certified fixed orthodontic courses by Indian dental academy
Diagnosis and treatment planning in implants .
INDIAN DENTAL ACADEMY
Leader in continuing dental education
• Pre implant
• Evaluation of
• Bone evaluation.
Existing occlusal plane, orientation.
Existing vertical dimension of
5. 1.Maxillomandibular arch relationship
6. 2.Temperomandibular joint status
3. Terminal splinted abutment.
7. Existing prosthesis.
4. Crown size
8. 5.Arch form(anteroposterior distance).
9. 6.Implant ideal permucosal position.
7. Root configuration
10. Missing teeth: location
8. Tooth teeth:
11. Missingposition number
12. Lip line at rest and during speech.
10. Arch position
13. Mandibular flexure.
14. Soft tissue support.
12. Periodontal status.
Pre implant considerations.
Existing occlusal plane, orientation.
Existing vertical dimension of occlusion.
Maxillomandibular arch relationship
Temperomandibular joint status
Arch form(anteroposterior distance).
Implant ideal permucosal position.
Missing teeth: location
Missing teeth: number
Lip line at rest and during speech.
Soft tissue support.
The relationship of centric occlusion to centric
relation is to be noted because.
Of potential need of occlusal adjustments to eliminate
deflective tooth contacts.
Evaluation of their potential noxious effects on the
For planned restoration.
Correction may involve one or more of the
1. Selective odontoplasty
2. Restoration with the crown (with or without Endodontic
3. Extraction of the offending tooth.
Existing occlusal plane orientation
• Aids to evaluate the needed changes.
– Pretreatment diagnostic wax up.
– Occlusal plane analyzer.
Following changes can be seen in opposing dentition
– In partially edentulous ridge more facial resorption may
require implant insertion more medial in relation to the
original central fossa of the natural dentition.
• A proper curve of spee and curve of Wilson are
indicated for proper esthetics and to prevent
posterior lateral interferences during excursions.
• A steep incisal guidance may help avoid posterior
interferences in protrusive movements.
– If its shallow,it may be necessary to plan recontouring or
prosthetic restoration of any posterior offending teeth.
– A mesially tipped mandibular third molar may greatly
compromise the implant placed in the maxillary posterior
– Endodontic therapy,
– And /or extrusions of adjacent or opposing natural teeth.
8-10 mm 7 mm
12 mm. 12 mm
• Results from vertical loss of alveolar bone and soft
• Increased space makes the placement of
removable prosthesis easier.
• In fixed restorations increased space makes
– Replacement teeth elongated.
– Placement of gingival tone materials
– Increased crown height
increased moment of
force on implants
increased risk of component
and material fracture.
Management of increased
• May be decreased by addition of onlay grafts
before implant placement.
– Autogenous and /or membrane grafts.
– Alloplastic grafts
• It improves
Crown –implant ratio
Permits wider implant selection.
Benefit of increased surface area.
Improves hygiene condition.
Lack of Interarch space.
• Results from
– migration of the opposing natural dentition into the
– History of tooth abrasion,attrition and skeletal
– Even when the opposing teeth are extracted or missing
the Interarch space is still less as the alveolar process
has followed the teeth.
Decreased abutment height
Inadequate bulk for esthetics and strength
Poor hygiene conditions.
Management of less Interarch
1. Surgical reduction of tuberosities.
2. Osteoplasty and /or soft tissue reduction
of implant region
3. Selective grinding
4. Prosthodontic restorations
5. Endodontic therapy.
Existing vertical dimension of
• Patients who have been partially or fully
edentulous for several years may exhibit a
• Assessment to be done as it influences
– Inter arch space
– Anteroposterior jaw relationship.
• Techniques used in traditional
prosthodontics can be used in this.
Maxillomandibular arch relationship
• An improper skeletal position may be
modified by orthodontics and/or surgery.
• Anterior edentulous maxilla decreases 40% within few
years at the expense of labial plate.
• Implants are placed lingual to original incisal position.
• Final restoration Is over contoured for
• Cantilevered force on the anterior implant body.
• To compensate for the increase in lateral loads and
moment of force
• additional implants
• increase in the anteroposterior distance between implants.
• An anterior cantilever on implants in the mandibular
arch may correct an angle’s skeletal class II jaw
• A complete denture cannot extend beyond the bone
support or neutral zone of the lips without decreasing
stability of the prosthesis.
• However implants can permit the placement of the
replacement teeth in a more ideal esthetic and
• The anterior cantilever is dependent on the presence of
sufficient anteroposterior distance between the
• To counter the cantilever effect, the treatment plan
should provide increased implant support.
• Edentulous maxillary posterior arches resorb
towards the palate.
• Ridge is medial to the opposing mandibular tooth
• Posterior teeth may be placed in a cross bite to
decrease the moment of forces developing on the
maxillary posterior teeth.
Temporomandibular joint status
• Signs and symptoms of dysfunction.
Limited jaw movements.
• Maximal opening is noted
– Normal 38-40 mm from maxillary incisal edge to
mandibular incisal edge.in angle’s skeletal class I
• Deviation on opening should be noted and
typically takes place on the same side as
• The patient should be able to perform
unrestricted mandibular excursions.
• Patient should ideally be free of symptoms
before implant therapy can be considered.
• Many patient with soft tissue prosthesis and
TMJ dysfunction benefit from the stability
and exacting occlusal aspects the implant
• Removable partial soft tissue –supported
restoration opposing the proposed implant
• Occlusal forces will change once the implant
supported prosthesis will be placed
• Forces will vary as underlying bone remodels.
• Constant maintenance and follow up are
indicated, including reline and occlusal evaluation.
• Existing prosthesis which has to be replaced
with implant supported prosthesis.
– To be evaluated for Esthetics
– Contour arrangement and position of the teeth
• Pretreatment prosthesis is indicated when
Patient unsatisfied with esthetics
Poor soft tissue health
Collapse of posterior support.
• Acceptable preexisting maxillary removable
prosthesis is used as a template for implant
• lip position and support provided by Labial
flange is evaluated .
• If support is less without flange, a
hydroxyapatite(HA) labial onlay graft is
Arch form (anteroposterior distance)
Edentulous arch forms are
1. Ovoid-most common.
2. Taperingfound in class II skeletal patients as a result of Para functional
habits during growth and development.
may result from initial formation of the basal skeletal bone
Labial bone resorption of the premaxilla region when
anterior teeth are lost earlier than the canine and posterior
• The distance from the center of the most
anterior implant to a line joining the distal
aspect of the two most distal implants is
called the anteroposterior distance or A-P
• It provides an indication of the amount of
cantilever that can be reasonably planned.
• The predominant factors to determine the cantilever
length are related to stress, not the A-P distance.
• Factors to determine length of cantilever.
Parafunction (most important)
Direction of force
• The arch form is an important
determinant when anterior implants are
splinted together to cantilever the
restoration to the posterior regions.
• In this situation square arch form
provides poorer prognosis than the
tapered arch forms.
• As a general rule, when 5 anterior
implants in the mandible are used for
the prosthesis support, the cantilevered
posterior section of the restoration
should not exceed 2.5 times the A-P
spread when all stress factors are low.
• In advanced anterior maxillary arch resorption the
implant may have to be placed at the canine
• The resulting restoration is a fixed,anteriorly
cantilevered prosthesis when the original arch
form is restored.
• Greater stress results for tapered arch forms
compared with square arch forms all other factors
• The cantilever to replace a tapered arch form
requires the support of additional implants of
greater width and number.
• In maxilla the recommended anterior cantilever
dimension is less than for the posterior cantilever
in the mandible as
– Bone is less dense
– Forces are directed outside the arch during excursions.
Implant ideal permucosal position.
• An implant placed in the improper position can
compromise the final results in esthetics
biomechanics and maintainnence.
• Use of surgical template for implant placement is
strongly suggested in most edentulous regions.
• It should provide both ideal implant permucosal
placement and angulations information.
Results in compromised
Angled abutment may help improve the condition.
It increases the forces on the crest of the bone
Labial cortical plate is much thinner and hence
cervical bone loss is common in these conditions.
• It is easier to correct in final restoration.
• Thicker lingual plate provides initial
• As implant body is half the diameter of the
adjacent teeth, the final crown is not
necessarily over contoured on the lingual
• An implant placed too far mesially or too distally
is of less consequence if lip does not expose the
cervical third of the restoration.
• The final restoration is constructed with the
interproximal incisal two thirds ideal for esthetics,
independent of implant placement.
• Hygiene is compromised, but the crown can be
designed to allow daily care.
Missing teeth: location
• The number and location of missing teeth
influences the prosthodontic treatment plan of the
• The second mandibular molar is not replaced in
posterior implant supported prosthesis.
• The mandibular first molar is designed to occlude
with the mesial marginal ridge of a natural second
molar to prevent extrusion.
Disadvantages of replacing mandibular
90% chewing efficiency is
forward of mid –first molar.
More lateral interferences in
10% greater bite force.
Location of mandibular
Less dense bone.
Submandibular fossa is
Less Interarch space for
8. Less access to occlusal
9. Hygiene is more difficult.
10. Cheek biting is more
11. Cross bite more often
12. More incision line opening
13. Greater mandibular flexure.
14. Greater cost to patient.
Maxillary second molar implant
is mostly indicated because.
• Poor bone density in the region and need
for added posterior support.
• No risk of Paresthesia.
• Implants do not extrude especially when
they are splinted.
Missing teeth: number
• Independent implant restorations not connected to
teeth cause fewer complications and longer success.
• The number of posterior pontics in fixed restoration
should not extend beyond two, and even this
condition is improved with independent implant
• Non precious metals deform approximately 50%
less than high noble alloys and therefore may be
selected for long span restorations supported by
Lip line at rest and during speech.
• Following lip positions are evaluated.
– Resting lip line
– Maxillary high lip line
– Mandibular low lip line.
• It is recommended to make the patient
aware of these existing lip lines and impress
upon them that these lip positions will be
similar after treatment.
Resting lip line
• Especially noted if maxillary anterior teeth are to
• The resting lip positions are highly variable,but in
general are related to the patients age.
• Older patients show fewer maxillary teeth at rest
and during smiling but demonstrate more
mandibular teeth during sibilant sounds.
• Extending crown height in maxilla to decrease the
age of smile may result into increased moment of
Maxillary high lip line.
• It is determined while the patient displays a
natural, broad smile.
• If patient has high lip position during
smiling, the prosthodontic requirements are
– Onlay grafts of HA may be indicated.
– Addition of pink porcelain.
Mandibular low lip line.
• It has to be observed during speech.
• In pronunciation of the “ s” sounds, or sibilants,
some patients may expose the entire anterior
mandibular teeth and gingival contour.
• Patients are often unaware of this preexisting lip
position and blame the final restoration for the
display of the mandibular gingiva, or complain
that the teeth look too long.
• The amplitude of the movement is 0.8 mm in
molar area and 1.5 mm in ramus area.
• As a consequence, complete cross-arch splinting
of posterior molar rigid, fixated implants is
usually contraindicated in the mandible
– Segment the restoration in 2 or more independent
– Non rigid connectors
– Insert posterior implants only in one section.
Soft tissue support
• Evaluation of soft tissue support is
primarily needed in planning for
• Shape of the ridge.
– Square: optimal resistance and stability.
– Flat: compromised factor for retention and
stability.support is adequate.
– Tapering ridges: poor stability.
• Ridge parallelism
– Rides parallel to occlusal plane : most
– Both ridges are divergent: stability of the
denture will be affected.
Evaluation of natural teeth
adjacent to implant site.
Terminal splinted abutment.
Decision making protocol for a
natural tooth abutment
5 to 10
Keep the tooth and restore as indicated.
Make an independent implant restoration. If
the natural tooth abutment must be
included,make it a “living pontic” by adding
more implants or splinting to additional teeth
with copings and a retrievable prosthesis
Extract the tooth and graft the site. Consider
an implant in the site after healing.
4 important components may contribute
movement to the implant –tooth rigid
The prosthesis and prosthetic component.
Tooth exhibits normal physiological movement
in vertical horizontal and rotational directions.
Amount of movement depends on
2. Amount of surrounding bone.
28 µm actual
Single pontic –6
under 10 Ib µm.
Two pontic span 48
Under 25 Ib force.
Horizontal Anterior 90-108
• There is extensive documentation that
implants can be connected rigidly to stable
• However occlusion should be modified so
that implant does not bear the major
portion of the load.
• Visual clinical evaluation by the human eye can
detect movement above 90 µm.
• When mobility of natural tooth can be observed,it
is above 90 µm and too great to be compensated
by the implant,bone,and prosthesis movement.
• criterion for joining an implant to natural teeth
– is that there be no observable clinical mobility of the
– No lateral forces should be designed on the implant.
• Implants should rarely be connected to anterior
– Anterior teeth often exhibit greater clinical mobility than
the implant can tolerate.
– Lateral forces applied to the restoration during
mandibular excursions will be transmitted to the
• When natural abutments show clinical mobility two
options are available.
– Place additional implants and avoid inclusion of natural
– Splinting of additional natural abutment to improve
stress distribution and obtain 0 clinical mobility.
• When an implant serves as a pier abutment
between two natural teeth,the differences in
movement between implant and tooth may
• Implant act as fulcrum of class I lever.
• Leads to uncemented abutment and
• To prevent the implant pier abutment from
acting as a fulcrum, a non rigid attachment
may connect the implant and the least
retentive crown or most mobile tooth.
• An implant does not undergo mesial
movement during function,so the nonrigid
connector location can be more variable.
• When natural abutment is the pier abutment
between two implants, a stress breaker is
• The tooth may then act as living
pontic,contributing less to the support,
provided the number of pontics is limited
and the implants are of sufficient
• The retention of a crown is influenced by the
diameter and height of the abutment.
• Crown height may be affected when Interarch
space is limited.
• Management of decrease d crown size.
– Splinting –improves retention but compromises access
for hygiene in the interproximal areas.
– Crown lengthening
– Minimal tapering
– Retentive elements such as grooves or boxes.
• The crown root ratio represents the height of the
crown from the most incisal or occlusal position to
the crest of the alveolar ridge around the tooth
compared with the height of the root within the
• Is important when lateral forces are expected
against the crown,as in mandibular excursions.
• The lateral forces develop a class I lever condition
on the tooth with fulcrum at the crest of the bone.
• Splinting may be indicated for better stress
• Found rarely but most ideal crown root ratio
for a fixed prosthetic abutment is 1:2.
• Common condition 1: 1.5
• Minimum requirement. 1:1.
• Crown to root ratio when opposing natural
teeth or implants and when serving as an
abutment for an implant tooth prosthesis.
• A natural abutment included in a combination of
tooth and implant supported prosthesis should
present a satisfactory pulpal condition or a root
• Exacerbation of Endodontic lesion after implant
surgery may result in adjacent implant failure.
• Some anterior teeth show wide incisal edges and
narrow cervical portions,especially if recession of
the gingiva has occurred.
• Pulpal exposure of the lateral horns are common
when preparing www.indiandentalacademy.com crowns
such teeth for full
• Past periodontally involved teeth are more at
risk of pulpal disease after tooth preparation.
• Apicoectomy procedures ,when indicated
,are best performed without use of amalgam
retrograde filling to avoid corrosion
byproducts in the area, which may
contaminate metal implants.
• Root configuration of a natural abutment may
affect the amount of additional stress the tooth
may withstand without potential complications.
• Favorable root configuration
– Curvatures of root.
• Unfavorable root configuration.
Maxillary second molar often presents varied root
• Any adjacent natural tooth with curved roots at the
apex must be carefully evaluated before implant
• Maxillary canine is often tilted 11 degrees and
exhibits a distal curvature to its roots.
• An implant placed in the premolar region may
inadvertently placed into the canine root apex
when the topography of the area is not
• Roots with circular cross-section do not represent
as good a prosthodontic abutment as those with an
ovoid cross section.
• Therefore maxillary premolar is a better abutment
than the maxillary central incisor,although their
root surface areas are similar.
• Maxillary lateral incisor exhibit les lateral
mobility than central incisor,as a result of its
• When adjacent teeth have been missing for
a long time ,the remaining natural abutment
has often drifted form its ideal position
• Correction of natural abutment should be
– Crown preparation
– Endodontic therapy before restoration
– Orthodontic movement.
• Orthodontic treatment can be planned in
conjunction with the healing phase for rigid
• Splinting incisor teeth is more common in implant
dentistry than traditional prosthodontics.
• Joining nonparallel teeth or splinting anterior and
posterior teeth in same prosthesis may be required.
• Several abutments may need Endodontic therapy
to achieve this goal.
• Selective extraction of incisors may even be
indicated if rotations or overlapping of teeth
represent unrealistic conditions for oral hygiene
• Indications for knife edged margin preparation for
– Interproximal areas of incisors,so pulp horns are not
– Onside of tooth tipped more than 15 degrees
• Apply when splinting anterior teeth or nonparallel abutments.
– On an implant post much smaller than the emergence
profile of its crown
– In the furcation region of multirooted teeth.
Root surface area.
• Greater the root surface area of proposed
abutment tooth ,the greater the support.
• Teeth affected by periodontal disease lose
surface area and represent poorer support
elements for a prosthesis.
• For a maxillary first molar, bone loss to the
beginning of the root furcation corresponds
to a root surface area reduced by 30%.
• Ante’s law requires the root surface area of
the abutment teeth to be equal to or greater
tan that of the teeth replaced by the pontics
of the fixed restoration.
• Although originally presented without
research or documentation,it has withstood
the test of time and serves as a clinical
• All carious lesions should be eliminated before
implant placement,even when the teeth will be
restored with crowns after implant healing for the
• As implants most often require several months of
healing after initial placement,the progression of
decay may alter the final treatment plan and loss f
• If Endodontic therapy becomes indicated
,obturation of the canals ideally should be
completed before implant surgery.
• The periodontal evaluation of natural abutments to be
connected to implants is identical to evaluation of other
fixed partial denture abutments.
• Adjacent implant sit e may be contaminated by bacteria
during periodontal surgery.
• Implant surgeon should decide if periodontal therapy is
indicated on the abutment teeth at the same time as
• Active infection should be kept to a minimum during
• If conditions of increased risk are present,tetracycline is
administered before implant surgery to decrease the
sulcular flora,which may contaminate the implant site.
Divisions of available bone
• Classification of available bone follows the
natural patterns of bone resorption in the
• Each division presents unique surgical and
Misch and Judy (1985)
Mandible : by Atwood. Maxilla by fallschussel
other bone classifications.
• Cawood and Howell.
• Weiss and Judy 1974 classification of mandibular
atrophy and its influence on subperiosteal implant
• Louisiana state university and Kent (1982)
classification of alveolar ridge deficiency designed
for Alloplastic bone augmentation.
• Zarb and lekholm (1985) residual jaw morphology
with the insertion of Branemark fixtures.
• Available bone
amount of bone in
the edentulous area
• It is measured in
Available bone height.
• The minimum height of available bone for
endoosteal implants is in part related to the
density of bone.
• The minimum bone height for predictable
long term Endoosteal implant survival
Height of available bone is measured from the crest of the
edentulous ridge to the opposing landmark. Which may be
Maxillary canine region
Floor of the nares
Mandibular canine region
Bone above the inferiorwww.indiandentalacademy.com
Available bone width.
• It is measured between the facial
and lingual plates at the crest of
the potential implant site.
• Root form implants of 4.0 mm
crestal diameter usually require
more then 5.o mm of bone to
ensure sufficient bone thickness
and blood supply around the
implant for predictable survival.
Available bone length.
• The mesiodistal length of avialble bone in an
edentulous area is often limited by adjacent teeth
• For a bone more tan 5 mm wide, a minimum
mesiodistal length of 7 mm is usually sufficient
for each implant.
• For bone less than 5 mm requires a 3.2 mm
implant with compromises such as less surface
area and greater crestal concentration of stress.
Available bone angulation.
• Ideally it is aligned with the forces of
occlusion and is parallel to the long axis of
the prosthodontic restoration.
• The alveolar one angulation represents the
root trajectory in relation to the occlusal
• Rarely does this bone angulation remain
constant after the loss of teeth.
• Maxillary anterior region
– Maxillary anterior teeth are angled more to
occlusal forces than any other teeth.
– Labial undercuts and resorption after tooth loss
mandate greater angulation of the implants.
• Posterior mandibular region.
– Submandibular fossa mandates implant
placement with increasing angulation as they
– Second premolar region –10 degrees
– First molar region –15 degrees
– Second molar region –20-25 degrees.
• In edentulous areas with a wide ridge,
– wider root form implants may be selected.
– Decreases the amount of stress transmitted to the crestal
– Such implants allow modifications up to 30 degrees
• Narrow yet adequate width ridge.
– Requires narrower design root form implant.
– Smaller diameter designs cause greater crestal stress and
may not offer the same range of custom abutments.
– The limits of the acceptable angulation of bone in narrow
ridge to 20 degrees from the axis of the adjacent clinical
crowns or a line perpendicular to the occlusal forces.
Crown –implant body ratio.
• The crown –implant body ratio impacts the
appearance of the final prosthesis and the amount
of moment of force on the implant and
surrounding crestal bone.
• The greater the crown height,the greater the
moment force or lever arm with any lateral force.
• As the crown-implant ratio increases,the number
of implants and/or wider implants should be
inserted to counteract the increase in stress.
Divisions of available bone.
Division B (Barely sufficient
• Division B ridge may be
converted to division A by
• the augmentation requires 4
to 6 months but can result in
improved crown – implant
ratio and more natural
• Implants may be placed at
the same time as
Osteoplasty,but the crownimplant ratio is increased.
Division C (compromised bone)
Division D (Deficient bone)
• Linkow (1970)
• Class I bone structure
– The ideal bone type consists of evenly spaced trabeculae
with small cancellated spaces.
– Very satisfactory foundation for implant prosthesis.
• Class II bone structure
– The bone has slightly larger cancellated spaces with less
uniformity of the osseous pattern.
– Satisfactory for implants
• Class III bone structure.
– Large marrow filled spaces exist between bone
– Results into loose fitting implants.
• Lekholm and zarb(1985)
• Quality 1
– Homogeneous compact bone
• Quality 2
– Thick layer of compact bone surrounding a core of dense
• Quality 3
– Thin layer of cortical bone surrounding dense trabecular
bone of favorable strength.
• Quality 4
– Thin layer of cortical bone surrounding a core of low
density trabecular bone.
Misch bone density classification
• D1 dense cortical bone
• D2 thick dense to
porous cortical bone on
crest and coarse
trabecular bone within.
• D3 thin porous cortical
bone on crest and fine
trabecular bone within.
• D4 fine trabecular
• D5 immature,
Factors of stress
• Normal forces exerted on teeth.
• Bite forces
Perpendicular to occlusal plane
Brief total period (9 min/day)
Force on each tooth : 20 to 30 psi
Maximum bite force: 50 to 500 psi
• Peri oral forces.
Maximum when swallowing (3 to 5 Psi )
Brief total swallow time (20 min/day)
Dental factors that affect stress primarily
The position of the abutment in the arch
The nature of the opposing arch
The direction of load forces
The crown –implant ratio.
• The most common cause of early loss of rigid
fixation during the first year of implant loading is
the result of Parafunction.
• Such complications occur with greater frequency
in the maxilla because of a decrease in bone
density and an increase in the moment of force.
• Parafunction may be categorized as absent,mild
moderate or severe.
• It is the vertical and horizontal ,or
nonfunctional grinding of teeth.
• Bruxism does not necessarily represent a
contraindication for implants but it
dramatically influences the treatment plan.
• Best way to diagnose is the to evaluate the
wearing of teeth.
• It is the force exerted from one occlusal
surface to the other without any movement.
• The forces are directed more vertically to
the plane of occlusion,at least in the
posterior regions of the mouth.
• Wearing of the teeth is not likely.
• Common clinical finding is the scalloped
border of the tongue.
Tongue trust and size.
• Parafuctional tongue thrust is the unnatural
force of the tongue against the teeth during
Position of abutment within the
• Biting force is greater in molar region and
decreases as it progresses anteriorly.
• Masticatory muscle dynamics are
responsible for the amount of force exerted
on the implant system.
• Forces recorded in woman are 20 lb less
than those in men.
• Younger patients need additional implant
support for the prosthesis for the longer
• Natural teeth transmit greater impact forces
through occlusal contacts than do soft tissue
borne complete dentures.
• Partial denture patients may record forces
which are intermediate between that of
natural teeth ad complete dentures and
depends on the location and condition of the
remaining teeth,muscles ,and joints.
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