Presented by:Dr.m.akouchakian Supervised by: Dr. Mansour Rismanchian And Dr.saied Nosouhian Dental...

1

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.


m.akouchekian 10


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


m.akouchekian 13


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


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


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


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


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


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


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.

m.akouchekian 100

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.

m.akouchekian 106

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

m.akouchekian 107

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.

m.akouchekian 111

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.

m.akouchekian 112

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

m.akouchekian 117

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

m.akouchekian 118

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.

m.akouchekian 119

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

m.akouchekian 120

Thanks for your attention

Presented by:Dr.m.akouchakian Supervised by: Dr. Mansour Rismanchian And Dr.saied Nosouhian Dental...

Documents

Transcript of Presented by:Dr.m.akouchakian Supervised by: Dr. Mansour Rismanchian And Dr.saied Nosouhian Dental...