single-tooth replacement: treatment options
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Single-Tooth Replacement: Treatment Options. Presented by:Dr.m.akouchakian Supervised by: Dr. Mansour Rismanchian And Dr.saied Nosouhian Dental of implantology Dental implants research center Isfahan university of mediacal science. Single-Tooth Replacement: Treatment Options. - PowerPoint PPT PresentationTRANSCRIPT
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SINGLE-TOOTH REPLACEMENT:TREATMENT OPTIONSPresented by:Dr.m.akouchakian
Supervised by: Dr. Mansour Rismanchian
And Dr.saied Nosouhian
Dental of implantology
Dental implants research center
Isfahan university of mediacal science
m.akouchekian 2
SINGLE-TOOTH REPLACEMENT:TREATMENT OPTIONS
chapter 16
m.akouchekian 3
Seventy percent of the dentate
population in the United States is
missing at least one tooth
Single-tooth replacement will most likely
comprise a larger percentage of
prosthetic dentistry in the future,
compared with past generations.
m.akouchekian 4
POSTERIOR MISSING TOOTH
The first molars are the first permanent
teeth to erupt in the mouth
often the first to decay
often play a pivotal role in the maintenance of the arch form and proper occlusal schemes
m.akouchekian 5
the adult patient often has had one or more crowns
fabricated to restore the integrity of the tooth and
replace previous large restorations.
Longevity reports of crowns have yielded very
disparate results, with the mean life span at failure
reported to be 10.3 years.
The primary cause of failure of the crown:
endodontic therapy
porcelain or tooth fracture (or both)
uncemented restoration
m.akouchekian 6
POSTERIOR SINGLE-TOOTHREPLACEMENT OPTIONS
m.akouchekian 7
insufficient vertical space
correction of the occlusal plane and maxillomandibular
relationships
prosthes
Regardless of the treatment selected, the interocclusal space must be assessed carefully.
m.akouchekian 8
REMOVABLE PROSTHESIS
A common axiom in restorative dentistry
:
use a fixed prosthesis whenever possible
RPDs are usually indicated to replace:
1. three or more posterior teeth
2. a missing canine and two or more
adjacent teeth
m.akouchekian 9
no reported advantages exist for an RPD replacing one posterior tooth.
REMOVABLE PROSTHESIS
m.akouchekian 10
REMOVABLE PROSTHESIS
the fear of other teeth shifting in the arch
the two primary reasons for the patientto consent to wearing the restoration
esthetics
m.akouchekian 11
RESIN-BONDED FIXED PARTIAL DENTURE
m.akouchekian 12
RESIN-BONDED FIXED PARTIAL DENTURE
m.akouchekian 13
RESIN-BONDED FIXED PARTIAL DENTURE
earlier perforated designs exhibited
lower survival rates
The majority of resin-bonded fixed
partial denture (FPO) failure occurs from
cement failure
survival rates : Max. Ant > mand. Ant > max. Post > mand. post
m.akouchekian 14
RESIN-BONDED FIXED PARTIAL DENTURE
Selection:
economics
maintain tooth structure on the abutment
teeth
transitional restoration
m.akouchekian 15
MAINTENANCE OF THE POSTERIOR SPACE
Replace a missing tooth to prevent :
tipping,extrusion, increased plaque
retention,caries, periodontal disease, and
collapse of the integrity of the arch
m.akouchekian 16
m.akouchekian 17
when the third molar and second molar are the only posterior mandibular teeth
missing
mandibular second molar is often not replaced
m.akouchekian 18
when the third molar is present
The mandibular second molar is usually replaced
m.akouchekian 19
Disadvantage of not replacea mandibular second molar
increased risk of caries, periodontal disease,or both
loss of proper interproximal contact with the adjacent tooth
extrusion and loss of the maxillary second molar
To preven extrusion of the maxillary second molare
a crown on the mandibular first molar include an occlusal contactwith the mesial marginal ridge of the maxillary second molar
the maxillary second molar bonded to the maxillary first molar
m.akouchekian 20
FIXED PARTIAL DENTURE
m.akouchekian 21
FIXED PARTIAL DENTURE
m.akouchekian 22
m.akouchekian 23
SINGLE-TOOTH IMPLANTS From 1993 to the present time, single-tooth
implants have become the most predictable
method of tooth replacement.
•A review of the
literature by Goodacre
from 1981 to 2003:
single-tooth replacement
with an implant had the
highest implant
prosthesis survival
rate(97%).
m.akouchekian 24
m.akouchekian 25
SINGLE-TOOTH IMPLANTS
the longevity of the implant crown has
not been adequately determined
However, lO-year data clearly indicate
an implant and its associated crown has
greater survival than an FPD
most common complication reported :
abutment screw loosening(did not cause
the prosthesis or implant to fail)
m.akouchekian 26
The consequences of early failure may be
greater for a single-tooth implant compared
with a three unit fixed prosthesis.
the implant failure almost always results in
bone loss
implant failure:
does not compromise the adjacent teeth
does not increase the risk of their loss
m.akouchekian 27
m.akouchekian 28
TRANSITIONAL RESTORATIONS Use in esthetic regions during implant healing
A removable transitional restoration:
load the soft tissue over a bone graft
compromise the result and volume of the
augmentation
cause bone loss, or perhaps even implant failure
from the early loading around the implant during
Stage I healing
depress the interdental papillae of the adjacent
teeth
m.akouchekian 29
a resin-bonded fixed restoration:
replacing teeth in the esthetic zone
provide an improved function
protect the region
In the esthetic zone when bone grafting is necessary
Use transitional restoration
m.akouchekian 30
Dont use of transitional posterior tooth
during bone augmentation and implant healing in a nonesthetic region (mandibular post)
overall cost of treatmentShort clinical crownsunfavorable occlusal relationships
m.akouchekian 31
IMPLANT BODY SELECTION
The most common problem associated
with a single tooth is abutment screw
loosening
1. an antirotational feature (i.e.,external or
internal hex)
2. Accuracy of component fit
3. abutment screw design
4. the number of threads
m.akouchekian 32
should be made of titanium alloy to
reduce the risk of long-term fracture
4 times more resistant to fracture than
grade 1 titanium
2 times as strong as grade 3 titanium
functional surface :
threaded implant > cylinderical imlplant
parallel walled implant > tapered implant
m.akouchekian 33
The ideal diameter of a single-tooth implant is
dependent on:
1. the mesiodistal dimension of the missing tooth
2. the buccolingual dimension of the implant site
1.5 to 2.0 mm from an adjacent tooth
1.5 mm from the lateral width of the ridge
intratooth posterior region:
at least 3 mm less than the mesiodistal dimension of
the missing tooth (from CEJ to CEJ)
3 mm narrower than the buccolingual dimension of bone
m.akouchekian 34
PREMOLAR IMPLANT REPLACEMENT The most ideal posterior tooth to replace with
an implant
1. The vertical available bone is usually
greater
2. almost always:
anterior or below the maxillary sinus (or both)
anterior to the mental foramen
3. The bone trajectory for implant insertion is
more favorable
m.akouchekian 35
maxillary premolars:
often in the esthetic zone
need for bone grafting is very common
Implant placement without bone grafting
recessed emergence profile
facial ridge lap to the crown
does not allow proper hygiene or probing
m.akouchekian 36
To ensure a proper esthetic result and to avoid the need for a crown with a ridge lap
the implant body is often positioned similar to an anterior implant, under the buccal cusp
improves the cervical emergence profile of the maxillarypremolar crown
m.akouchekian 37
at a distance of 2 mm below the CEJ The natural
premolar:
root diameter is 4.2 mm consequence
most common implant diameter is about 4mm at the
crest module.
when the mesiodistal space is 7 mm or greater:
1.5 mm of bone on the proximal surfaces adjacent to the
natural teeth
when the mesiodistal dimension is only 6.5 mm:
3.5-mm implant is suggested
m.akouchekian 38
The maxillary canine root is often angled 11
degrees distally and presents a distal curve 32% of
the time
placed parallel to the canine root, and a shortersecond premolar apices
may be located over the
mandibular neurovascular
canal or maxillary sinus:
reduced height of bone
a shorter implant
m.akouchekian 39
FIRST-MOLAR IMPLANT REPLACEMENT Its mesiodistal dimensionusually ranges from 8 to 12 mm
The magnified occlusal
forces (especially important
in parafunction) may cause:
bone loss
complicate home care
Increase abutment screw
loosening
increase abutment
or implant failure because of
overload.
m.akouchekian 40
FIRST-MOLAR IMPLANT Rangert et al:
overload-induced bone resorption appeared to precede
implant fracture in a significant number of single-molar
implant restorations.
When possible, a larger-diameter implant should be
inserted to enhance the mechanical properties of the
implant System:
increased surface area
stronger resistance to component fracture
increased abutment stability
enhanced emergence profile for the crown
m.akouchekian 41
FIRST-MOLAR IMPLANT
use of wide-diameter implants:
1. in bone of poor quality
2. for the immediate replacement of failed implant
larger-diameter implant:
does not require as long an implant
Is a benefit in post
(anatomical limitations and landmarks, such as the maxillary sinus or mandibular canaI)
m.akouchekian 42
FIRST-MOLAR IMPLANT When the mesiodistal dimension is 14 mm or
greater
two 4-mm-diameter implants should be considered
Eliminate the mesiodistal offset loads to the
prosthesis
greater total surface area
More stress reduction
reduces the incidence of
abutment screw loosening
m.akouchekian 43
FIRST-MOLAR IMPLANT
whenever possible,two implants should be used to replace a larger singlemolar space to reduce cantilever loads and abutment screw loosening
m.akouchekian 44
FIRST-MOLAR IMPLANT
subtracting 6 mm:
1.5 mm from each tooth for soft tissue and
surgical risk
3 mm between the implants
and dividing by 2
m.akouchekian 45
FIRST-MOLAR IMPLANT When the mesiodistal space is 12 to 14 mm:
the treatment plan of choice is less obvious
A 5-mm-diameter implant may result in
cantilevers up to 5 mm on each marginal ridge of
the crown
two implants present a greater surgical,
prosthetic, and hygiene risk
The primary goal is to obtain at least 14 mm
of space
m.akouchekian 46
FIRST-MOLAR IMPLANT
Additional space may be gained in
several ways:
1. Enamoplasty of the adjacent teeth's
proximal contours
2. Orthodontics to
upright a tilted
Second molar
m.akouchekian 47
FIRST-MOLAR IMPLANT
3. one implant is placed buccal and the other
on a diagonal toward the lingual
increases the mesiodistal space by
0.5 to 1.0 mm
m.akouchekian 48
FIRST-MOLAR IMPLANT
In the mandible:
Ant. implant is placed to the lingual
distal implant is placed to the facial
access of a floss threader from the
vestibule into the intrairmplant space
occlusal contacts on
the central fossa of buccal
aspect of the mesial implant
m.akouchekian 49
FIRST-MOLAR IMPLANT In the maxilla:
anterior implant is placed to the buccal
distal implant to the palatal region,
to improve the esthetics
distal occlusal contact is
Placed over the lingual cusp
mesial occlusal contact is
located in the central fossa
access of a floss threader
from the palatal
m.akouchekian 50
FIRST-MOLAR IMPLANT
m.akouchekian 51
MAXILLARY ANTERIOR TOOTHREPLACEMENT
m.akouchekian 52
ESTHETIC MAXILLARY ANTERIOR TOOTHREPLACEMENT
is often the most difficult procedure to
perform in all of implant dentistry
highly esthetic zone
requires both hard (bone and teeth) and
soft tissue restoration
The soft tissue drape is often the most
difficult aspect of treatment
m.akouchekian 53
MAXILLARY ANTERIOR TOOTHREPLACEMENT
m.akouchekian 54
FIXED PARTIAL DENTURE
can be fabricated in shorter time
is more predictable in the short term
often satisfies the criteria of normal
contour, comfort,function, esthetics,
speech, and health
However, 7-to 9-year survival estimates
for a three-unit FPO are often less than
75%
m.akouchekian 55
FIXED PARTIAL DENTURE The most common complications associated with FPD
failure:
caries
endodontic complications(including fractures)
uncemented restorations(leading to decay)
risk of endodontic treatment :
15% for an FPD abutment
3% to 5% risk for a single crown
additional tooth preparation for parallelism of the abutments
the repreparation of teeth after prosthesis failure
the increased risk of decay on the abutment teeth
m.akouchekian 56
ADVANTAGES OF A FIXED PARTIAL DENTURE
Patient Compliance and Patient Fear
an implant restoration:
many steps of treatment
Orthodontics,Soft tissue surgeries, bone
graft
surgery, implant surgery, and several
prosthetic steps
m.akouchekian 57
Time of Treatment
The time required for an implant to heal
and be restored :3 to 6 months
If bone grafting and soft tissue
rehabilation are required: more than 1
year
a traditional three-unit fixed
prosthesis:less than 3 weeks
m.akouchekian 58
Consequence of Failure
The consequences of short-term failure of bone graft, implant, or
prosthetic are greater for a single-tooth implant, compared with a
three-unit fixed prosthesis
The implant failure may result in:
bone loss (especially when it occurs in the anterior regions)
may include the support system of the adjacent teeth
soft tissue recession
devastating effects on the esthetics
bone grafting may be required
Additional soft tissue reconstruction
These additional procedures are most often at the expense of the doctor
m.akouchekian 59
The most common contraindication for a traditional fixed prosthesis and indication for a single-tooth implant in the anterior regions of the mouth
is the patient's desire
m.akouchekian 60
Cost to Patient
The laboratory fee to the doctor for three
crowns:low.
The implant body, abutment,analog, and final crown
fee:more expensive
Although the initial cost of treatment for an implant
single crown: higher
implant reconstruction was a better financial option
in the long term
m.akouchekian 61
Adjacent Tooth Mobility
the adjacent teeth of the anterior implant
site should exhibit minimum mobility
if all other periodontal indices are normal,
Natural tooth longevity is not related to
mobility
a traditional FPD decrease the abutment
mobility
m.akouchekian 62
Unfavorable Tooth Size and Position
the maxillary anterior central incisors may be
misplaced, angled, rotated, or smaller than ideal =>
An FPD replacing a lateral incisor:
improve the position and size of the central incisor
The canine may be made slightly narrower to make the
lateral incisor similar in size to the contralateral incisor
several cosmetic advantages especially when the
lateral edentulous sites are smaller than 5 mm in width
m.akouchekian 63
CANTRAINDICATIANS FOR A FIXED PARTIAL DENTURE
m.akouchekian 64
CANTILEVERED FIXED PARTIAL DENTURE worse prognosis than a traditional FPD
The genesis of failure is usually an uncemented
restorationwhen the canti lever is
short,limited occlusion on
the pontic exists, limited
mesiodistal space
exists(less than 5 mm)
=> a cantilever may be
indicated in the anterior
region
m.akouchekian 65
REMOVABLE PARTIAL DENTURE No short- or long-term clinical studies exist in the literature for
single anterior tooth replacement with an RPD.
The usual indication :economics
the easiest interim treatment modality during submerged implant
healing
Loading of a bone graft with an RPD during initial healing :
increase the risk of micromovement
decrease the success rate of a bone augmentation
Therefore if a bone augmentation is indicated and an RPD is
used, it should have a cast framework with occlusal rests to
prevent rotation and loading of the soft tissue during function.
m.akouchekian 66
RESIN-BONDED RESTORATION
has a higher survival rate in the
maxillary anterior region than any other
location in the mouth.
The primary indication:
a transitional restoration during bone
and soft tissue grafts before implant
placement
m.akouchekian 67
Two modifications:
1. no enamel preparation exists on the abutment teeth and the
metal substructure design is extended in areas of enamel that
are gingival to the occlusal contact zones (decreases retention)
2. An acrylic removable overlay prosthesis, or a flipper is fabricated
m.akouchekian 68
RESIN-BONDED RESTORATION
m.akouchekian 69
SINGLE-TOOTH IMPLANT
More clinical studies have been
conducted for a maxillary anterior
single-tooth replacement with an
implant than any other treatment
option.
Retrospective reports are available
many prospective clinical studies
confirm the data of previous reports
m.akouchekian 70
SINGLE-TOOTH IMPLANT The maxillary anterior single-tooth implant has the
highest success rate compared with any other
treatment option to replace missing teeth with an
implant restoration
recently, a trend toward single-stage and
immediate-extraction implants has emerged. This
appears especially attractive in the maxillary
anterior region, where the soft tissue drape is ideal
before the extractionand patients are more anxious
to have a fixed replacement.
m.akouchekian 71
SINGLE-TOOTH IMPLANT
m.akouchekian 72
AGE LIMITATIONS The minimum age of the implant patient is more often a concern for maxillary
anterior tooth replacement,especially for congenitally missing teeth
implants:
1. do not erupt along with adjacent teeth
2. Do not become secondarily displaced in space as do ankylosed teeth during
growth of the jaws
many implants placed in adolescents with residual growth may be in infraposition after 10 years
1. a greater soft tissue pocket around the implant 2. Tissue shrinkage3. peri-implant conditions
m.akouchekian 73
AGE LIMITATIONS The growth of the maxilla occurs in three distinct planes:
1. transverse (width)
2. sagittal (length)
3. vertical
The transverse growth of the anterior maxilla is
completed before adolescence
The sagittal growth is the result of growth at the suture
and bone apposition in the maxillary tuberosity region
m.akouchekian 74
AGE LIMITATIONS
The most variable growth of concern is the
sagittal growth, because the premaxilla
may advance downward and forward or
primarily downward
As much as 25% of this displacement is lost
as the result of resorption at the anterior
=>facial bone resorption of the maxillary
implants placed before completionof growth
m.akouchekian 75
AGE LIMITATIONS
In premaxilla growth should be
completed before implant placement.
when cessation of growth and
development is undetermined =>
Multiple implants should not be splinted
across the midline in the adolescent.
m.akouchekian 76
AGE LIMITATIONS during the growth, teeth shift mesially.
between the ages of 10 and 21:
posterior segment (canine to molar):
moves anaverage of 5 mm mesially
the anterior segment: moves an average of 2.5
mm
Therefore an implant placed too early in the
growthperiod could impede the mesial shift,
thus resulting in an asymmetrical arch
m.akouchekian 77
AGE LIMITATIONS
The vertical growth continues
well after transverse and sagittal growth.
The Clinical reports have shown that:
implants in the anterior maxilla at the age of
7 may be located up to 10 mm apically
compared with the neighboring teeth 9 years
later
solitary implants placed at the age of 12 will
be in infraocdusion 5 to 7 mm 4 years later
m.akouchekian 78
AGE LIMITATIONS
As a general rule:
the lateral incisor may be inserted at a
younger ge than a central incisor or canine
less obvious to the eye when lateral incisors
are at different height positions, compared
with central incisors.
It is not unusual for a lateral incisor to be
shorter than the adjacent teeth
m.akouchekian 79
AGE LIMITATIONS Misch et al have created four guidelines for implants placed in
younger patients:
1. the chronological age of the patient
The chronological age of growth cessation :
for girls from 9 to 15 years and
for boys 11 to 17 years
As a general rule: implant insertion inthe anterior maxilla is
delayed:
for female patients untilat least 15 years
male patients until 18 years of age.
However, this guideline is too variable to be used alone =>
ideally, age is related to the patient's biological age
m.akouchekian 80
AGE LIMITATIONS
2. endocrine changes
The female patient should be able to menstruate
the male patient should have body hair, voice
changes
3. size of the the child
implant patient should have greater height than their
same-sex parent
The size of the patient is more important than
the age
m.akouchekian 81
AGE LIMITATIONS
4. the patient has not grown in the last 6-
month period
This criterion is easier to observe than
cephalograms or hand-wrist films with a 2-
year evaluation period.
m.akouchekian 82
AGE LIMITATIONS The two criteria that make the implant site most at risk:
1. a male patient
2. a central incisor
a delayed growth spurt :
a male patient :4-inch change in height
female patient may grow 1 to 2 inches
If all four criteria are fulfilled (i.e., minimum age, endocrine
changes, recent stature growth, 2-year lateral cephalometric
radiographs with no changes) => it is very likely the patient has
completed their maxillary anterior jaw growth =>the implant
may be inserted with little risk or compromise
m.akouchekian 83
ESTHETICS the natural central incisor and canine teeth
are often larger in their faciopalatal dimension
at the CEl than the mesiodistal dimension
The implant is round in cross section
the cervical esthetics of a single-implant crown must
accommodate a round-diameter implant and balance
hygiene and esthetic parameters
Often a soft tissue model is required to transfer the soft
tissue clinical condition to the laboratory. Rarely are these
unique needed for a crown on a natural tooth
m.akouchekian 84
CROWN HEIGHT SPACEPatients with:1. Angle's Class II Division II skeletal patterns2. an inadequate maxillornandibular relationship3. severe deficiency in the VD
are poor candidates for many treatment options
without prior corrections ,they are contraindicated for dental implants
m.akouchekian 85
MESIODISTAL SPACE The smallest-diameter implant body:3.2 mm
the crest module of these two-piece implants :3.5 mmmor more
the mesiodistal edentulous space for a two-piece implant should be
6.5 mm or greater
The average maxillary lateral incisor is 6.6 mm
patients with congenitally missing teeth often have contralateral anterior
teeth narrower than typical=> orthodontic therapy to increase the
intra tooth space is inadequate
when the lateral incisor is missing, the root of the adjacent teeth may be
angled toward the edentulous site, further decreasing the intratooth bone
dimension for implant => Orthodontic treatment to reposition the roots out
of the edentulous root space may not be accepted by the patient
m.akouchekian 86
MESIODISTAL SPACE One-piece dental implants may be fabricated in
2.5- mm to 3.0-mm diameters to accommodate a
reduced mesiodistal dimension criterion
do not have a microgap
the vertical defect is narrower than most two-piece
implant systems
they may be placed as close as 1 mm from an
adjacent tooth
can accommodate a 5-mm mesiodistal missing tooth
space
m.akouchekian 87
BONE HEIGHT The available bone for implant insertion
in esthetic regions will greatly influence:
the soft tissue drape
implant size
Implant position (angulation and depth)
The final esthetic outcome
not only the available bone volume is necessary
also the position of the osseous crest is specific
The ideal midcrestal position of the edentulous
site:2 mm below the facial CEj of the adjacent teeth
m.akouchekian 88
BONE HEIGHT the interproximal bone:
should be scalloped
3 mm more incisal than the midcrestal position
Becker et al. Found:
the range of interproximal bone height above the
midfacial scallop was from less than 2.1 mm to
more than 4.1 mm
2.1 mm :flat
2.8 mm : scalloped
4.1 mm :pronounced scalloped
m.akouchekian 89
The flat anatomy => square tooth shape
the scalloped => ovoid tooth shape
pronounced scalloped =>triangular-shaped tooth
However, these relationships do not always exist
When a flat interdental-to-crest dimension is found on triangular teeth
=> the interproximal space will usually not be filled with soft tissue
because the dimension of the interproximal contact to the bone will be
greater than 5 mm.
when a single-tooth site has inadequate bone height at the crest
and the adjacent roots also have lost bone =>
Orthodontic extrusion of the teeth may be considered (To grow crestal bone
height on the adjacent roots,in relation to the ideal crest of the ridge)
m.akouchekian 90
FACIOPALATAL WIDTH Most of the conditions that lead to single-tooth loss result
in the loss of some or all of the facial bone
within the first year of tooth loss :a 25% decrease in
faciopalatal
within 3 years: a 30% to 40% decrease
After 3 years: it almost never presents adequate available
bone for the properly sized implant.
m.akouchekian 91
FACIOPALATAL WIDTH Because:
1. the labial plate is very thin compared with the palatal plate
2. facial undercuts are often found over the roots of the teeth
=> The bone width loss is primarily from the facial region
m.akouchekian 92
FACIOPALATAL WIDTH
The amount of available bone width
(faciopalatal) should be at least 2.0 mm
greater than the implant diameter at
implant insertion and ideally more than
3 mm greater in width
m.akouchekian 93
SOFT TISSUE DRAPE When a tooth is lost:
the thin interseptal bone disappears
the bone remodels in a sloping fashion
from the palatal to the more apical facial bony plate
the interdental papillae are often depressed
The use of a soft tissue removable prosthesis often
accelerates the collapse of the soft tissue and its apical
migration
Soft tissue manipulation to restore their proper contour
is often required in conjunction with implant therapy.
m.akouchekian 94
m.akouchekian 95
SPECIFIC SINGLE-TOOTH IMPLANTINDICATIONS
Anodontia
The most common maxillary anterior tooth replaced by an implant
is a central incisor lost from trauma (e.g.,endodontic failure,
fracture, root resorption) and/or a lateral incisor lost as a result of
agenesis
in a lateral incisor:
the ideal cervical region of the tooth is similar to the implant diameter •the roots of the adjacent natural teeth often impinge on the edentulous bone•the mesiodistal length is insufficient
orthodontic therapy before implant placement should often be considered
m.akouchekian 96
SPECIFIC SINGLE-TOOTH IMPLANTINDICATIONS
When the patient is missing a maxillary lateral incisor, space closure is
less often indicated:
When a maxillary canine is orthodontically moved to a lateral
position:
1. The midline between the central incisors is often shifted to the missing tooth
side.
2. The canine eminence over the canine root is positioned under the
nose=>creat a depression lateral to the naris, and a less full maxillary lip
on one side of the midline.
These differences are more evident as the patient ages
3. The maxillary canine is larger faciopalatally than mesiodistally => the cervical
emergence is different from the contralateral incisor, even when restored with a
laminate facing.
4. The height of gingival contour is also higher than the lateral incisor on the other
side of the arch.
m.akouchekian 97
SPECIFIC SINGLE-TOOTH IMPLANTINDICATIONS
The missing maxillary lateral incisor is the tooth most often replaced with a
dental implant because the other orthodontic or prosthetic options are
usually poor alternatives.
m.akouchekian 98
The treatment options are usually different for a mandibular
second premolar compared with a maxillary lateral incisor.
A congenital missing mandibular second premolar
1. the deciduous molar may be extracted patient in 5 to 6 years old.
2. The permanent first molar may then erupt in a more mesial position
3. When the first deciduous molar is lost naturally (around the age of 9 to 11
years)
4. the first permanent premolar and first molar may be orthodontically
positioned adjacent to each other
This approach eliminates the need for a second premolar replacement
no required to bone graft, implant surgery, or crown (or combination of
these treatments)
Very few disadvantages exist to the use of orthodontics to eliminate this
posterior missing tooth space.
m.akouchekian 99
SPECIFIC SINGLE-TOOTH IMPLANTINDICATIONS
When the deciduous second molar is maintained:
it often becomes ankylotic
the opposing maxillary second premolar extrudes
the mesiodistal space is larger than the usual
premolar(Because the deciduous molar is 1.9 mm larger
than a premolar)
The deciduous tooth does not have a buccolingual width of
bone => can not use a larger-diameter implant.
The crown for this larger tooth dimension is supported by a
regular-size implant, which increases forces on the
abutment screw and increases the risk of screw-loosening
complications.
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ORTHODONTIC IMPLANT SITE DEVELOPMENT In specific situations, the management of the patient
in the early treatment phase may require
orthodontics before the implant insertion to replace
the missing tooth:
1. Space oppening
2. congenitally missing teeth
3. If bone height is insufficient and bone loss is also
present on the adjacent teeth
4. when the patient has a failing tooth
m.akouchekian 101
Missing lateral incisor in a child before the eruption of the permanent canine,
Kokich proposed the following treatment modality:
1. The maxillary deciduous lateral incisor is prematurely extracted.
2. The permanent canine is encouraged to erupt in the missing lateral incisor
position => the bone around the canine forms in the lateral incisor position.
3. after the eruption of the permanent canine in the lateral position, The
deciduous canine is extracted
4. The canine is orthodontically retracted into the ideal canine position.
5. The remaining lateral incisor bone volume is abundant and ideal for an
endosteal single-tooth implant.
6. After growth and development of the child has occurred, an implant may be
inserted.
In this manner, a bone graft will not be required before implant
m.akouchekian 102
ROOT RESORPTION Root resorption may cause the loss of a single
anterior tooth.
Two major categories of root resorption:
1. external
2. Internal
when structural failure is evident and the extraction of
the tooth is eminent, two different treatment options
related to the type of resorption exist.
Internal root resorption:
The treatment of choice is often orthodontic extraction
m.akouchekian 103
a 3-month extraction process produces sufficient movement
so that the remaining root diameter in the bone is smaller than the implant
diameter.
after 3 months of orthodontic extrusion, no void exists around the implant at
the time of extraction and implant insertion.
m.akouchekian 104
m.akouchekian 105
When external root resorption is the cause of structural failure
of the tooth root,
Bone, replacing the root defect
No evidence of a periodontal ligament space around the defect is
seen
orthodontic extrusion is not possible
Delaying the extraction as long as possible
the remaining root segments may be cored out during
the implant osteotomy procedure
If the surgical defect is too large for immediate implant
insertion, then the osteotomy is grafted and the implant
procedure is delayed.
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REMAINING MAXILLARY ANTERIOR TEETH to obtain an ideal result When the maxillary incisor single-
tooth replacement:
not only evaluate the edentulous site but also the
remaining anterior teeth
the adjacent teeth most often dictate its length, contour,
shape, and position
The patient, once fully informed of the existing
discrepancies and their potential negative effect on the
envisioned result, may decide to:
address and correct the existing problems of the adjacent teeth
simply elect to accept the compromise
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TOOTH SIZE The two maxillary central incisors should
appear symmetrical and of similar size
when the missing tooth is a central incisor with a mesiodistal space
less or more than the size of the corresponding central incisor:
1. Orthodontic correction is strongly encouraged
2. modify the existing central incisor with a veneer to make it
similar in size and shape to the missing tooth restoration
lowering the mesial interproximal contact
Making the two centrals more square shaped
Decreases the height requirement of the papilla
The shades of the two centrals are also easier to match when made at the
same time in the laboratory.
m.akouchekian 108
TOOTH SIZE
Because the clinical crown height of an implant
supported central incisor is often longer than the adjacent tooth,
an esthetic crown lengthening on the natural tooth may be used
to align the gingival margins
a crown-lengthening procedure on the natural tooth, may be more
predictable than attempting to cover the implant crown with soft
tissue
m.akouchekian 109
TOOTH SHAPE Three basic shapes of maxillary anterior teeth exist:
1. square
2. ovoid
3. Triangular
The tooth shape will influence the interproximal contact and the gingival embrasure.
The square tooth shape is the most favorable to obtain an ideal soft tissue drape and papillae
around the crown
the interproximal contact is more apical
more tooth structure fills the interproximal region
a triangular tooth shape has
a more incisal interproximal contact
a steeper gingival scallop
farther from the interproximal bone
a space often exists between the interproximal contact and the interdental papilla of the remaining
teeth
When the soft tissue fills the interproximal space of the remaining anterior teeth that have a
triangular shape, the tissues may be very liable and easily vanish during the healing phases
after implant surgery.
m.akouchekian 110
TOOTH SHAPE The tooth shape also affects the topography of the underlying
hard tissues.
The roots of triangular tooth shapes are positioned farther apart :
Have thicker facial and interproximal bone
Decrease the amount of crestal bone loss after an extraction
the prognosis for an immediate implant insertion is more favorable
provide the recommended 1.5 mm or more of interproximal bone from
the adjacent tooth
The square shaped tooth:
have less interproximal bone between the roots
a greater risk of crestal or interproximal bone loss with an immediate
implant insertion
less favorable for immediate implant insertion after extraction.
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SOFT TISSUE DRAPE The height of the maxillary lip when smiling (high lip line) is one
of me most important criterion to evaluate when observing me
cervical region of the maxillary anterior teeth.
Ideally:
the height of the maxillary lip should rest at the junction of the
free gingival margin on the facial aspect of the maxillary
centrals and canine teeth => the interdental papillae are
visible, but little gingival display is seen over the clinical crowns.
Almost 70% of patients have this ideal smile position.
A "gummy"smile displays more than 2 mm of soft tissue above
the clinical maxillary crowns and is more acceptable in the
female patient.
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SOFT TISSUE DRAPE Under ideal conditions in the maxillary anterior region:
interproximal contact should begin in the incisal third
the bone:
In midfacial: 2 mm below the CEl
in the interproximal region : 3 mm more incisal the CEl
The soft tissue:
In midfacial :3 mm above the bone at the midfacial position (1 mm
above the CEl)
in the interproximal region : 3 to 5 mm above the interproximal bone
Therefore if the interproximal contact is within 3 to 5 mm of
the interproximal bone, then the interdental papilla will most
often completely fill the space
m.akouchekian 113
SOFT TISSUE DRAPE
The higher the gingival scallop:
the higher the risk for gingival loss after
extraction
the less likely the surgical and restorative
procedures will be able to restore an ideal soft
tissue contour
a flatter gingival scallop:
minimal tissue shrinkage
more ideal outcome
m.akouchekian 114
SOFT TISSUE DRAPE The biotype of the gingiva is usually called
thick or thin.
Thicker tissue:
more resistant to the shrinkage or recession
more often leads to the formation of a periodontal
pocket after bone loss.
Thin gingival tissues:
more prone to shrinkage after tooth extraction
more difficult to elevate or augment after tooth loss.
m.akouchekian 115
SOFT TISSUE DRAPE According to Kois:
predictability of the maxillary anterior single-tooth implant is
ultimately determined by the patient's own presenting
anatomy.
Favorable conditions include:
1. when the tooth position is more coronal relative to the full
gingival margin
2. square tooth shapes
3. flat scallop periodontium forms
4. thick periodontium biotypes, and
5. high (<3 mm) facial osseous crest positions of the teeth and
midcrestal
m.akouchekian 116
SOFT TISSUE DRAPE Unfavorable patient anatomy :
1. aligned or apical preexisting tooth (relative
to the free gingival margin)
2. Triangular tooth shapes
3. high scallop periodontium form
4. thin periodontium types
5. low (>4 mm) facial osseous crest positions
in relation to adjacent teeth and midcrestal
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IMPLANT CREST MODULE DESIGN The two most common complications of anterior singletooth implant
replacement:
1. abutment screw loosening
2. crestal bone loss
Both of these conditions are in part related to the implant crest module design
to decrease in abutment screw loosening: an antirotational feature
to decrease crestal bone loss:
The crest module of an implant body should also be designed to transmit some
compression and tensile forces to the crestal bone.
Smooth metal on the crest module transmits shear forces to the bone => increases
the crestal bone loss
smooth metal collars on the implant crest module should be limited to approximately
0.5 mm
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IMPLANT SIZE
the implant body should obviously not
be as wide as the natural tooth or
clinical crown=>the emergence contour
and interdental papillae region cannot
be properly established.
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IMPLANT SIZE The ideal width of bone would allow at least 1.5
mm on the facial aspect of the implant
if a vertical defect forms around the crest module, that
defect would not become horizontal and change the
cervical contour of the facial gingiva
the faciopalatal width dimension is not as
critical on the palatal aspect of the implant
1. the palatal bone is dense cortical bone and more
resistant to bone loss
2. the palatal area is not within the esthetic zone
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Thanks for your attention