This document discusses single tooth dental implants. It provides information on: - The goals of single tooth implants which is to mimic the function and esthetics of natural teeth. - Key factors for achieving a sound esthetic result including bone and gingival contours, implant positioning, and ceramist skills. - Diagnosing implant cases by assessing hard and soft tissues and treatment planning the surgical and restorative aspects. - Guidelines for restoration design, implant placement, and occlusion to ensure biomechanical success and esthetics.

1. 18. Single Tooth Implants
Mete Fanuscu DDS
John Beumer III DDS, MS
Division of Advanced Prosthodontics, Biomaterials and
Hospital Dentistry, UCLA
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2. Single Tooth Implants
The goal with the single tooth implant restoration is to mimic function
and esthetics of the natural tooth.
A sound esthetic result is dependent upon:
! Optimal bone and gingival contours
! Accurate 3-D implant positioning
! A good ceramist

3. Single Tooth Implants
! Successfully used since late 1980s to replace
!
!
!
!
single teeth, both in the anterior and posterior
sites.
Implant loss has been reported to be < 5%.
No difference has been noted between sites in
maxilla and mandible.
Failures -About 50% have been pre-prosthetic
and 50% post-prosthetic
Complications include screw loosening, fistulas
at the implant –abutment level, esthetic
problems and post-operative neurosensory
disturbances.
Esposito et al, 1998

4. Working up The Single Tooth
Implant Case
! Diagnosis: Assessing hard and soft tissues, and their
relations to each other
-Clinical Evaluation
-Study Models
-Implant Template
-Imaging Evaluation
! Treatment Plan: Designing and sequencing surgical
and restorative aspects of the treatment.
-Restorative Design
-Surgical Design
! Therapy: Execution of the clinical procedures.

5. Diagnosis - Clinical Evaluation
! A- Edentulous tissues
! B- Residual edentulous space
! C- Adjacent teeth
! D- Opposing teeth
Functional and esthetic outcome of the single tooth implant therapy
depends on the proper clinical analysis of these four elements.

6. Diagnosis - Clinical Evaluation
A- Edentulous tissues
Amount of attached tissue is important in establishing periodontal
health around the implant crown.
! Achieving ideal soft tissue form and implant position is dependent
upon residual tissue contours. Interdental papilla height and buccal
plate should be carefully analyzed for deficiencies. These deficiencies
might effect functional and esthetic outcome of the implant restoration.
!
Flat papilla causing dark space
Adequate plate
Deficient plate

7. Diagnosis - Clinical Evaluation
Buccal plate deficiency in single tooth site
! Following extraction, particularly if traumatic, the
labial plate resorbs
! Resorption creates a site that dictates a palatal
placement and a ridge lapped restoration
Implants placed in
such sites lead to :

8. Diagnosis - Clinical Evaluation
Labial or Buccal plate deficiencies - Single tooth sites
! Ridge lapped restorations
! Hygiene is made more difficult
! Esthetics is compromised in patients
with a high smile line who display
significant amounts of gingiva
! Esthetics is compromised because
most such patients lack an
interdental papilla (arrow)

9. Bone augmentation for building the site
Horizontal Deficiencies
Woven Bone
Grafting anterior horizontal deficiencies
has been relatively predictable due to
minimal loads usual in this region.

10. Horizontal Deficiencies
Bone augmentation
Grafting serves to restore bone and soft tissue
contours to enhance the final esthetic result by
idealizing implant position

11. Horizontal Deficiencies
Bone augmentation
Normal Bone vs. Grafted Bone
Lamellar
Bone
The bone implant
interface is
compromised in sites
with woven bone. At
some sites, the
woven bone is not
replaced with dense
lamellar bone.
Woven Bone
Result: The load carrying capacity of implants in
grafted bone may be compromised.

12. Diagnosis - Clinical Evaluation
B- Residual edentulous space
!
!
!
Interarch distance should be minimum 2 mm in the anterior sites
and 4 mm in the posterior sites.
Mesio-distal distance should be about 7 mm. When there is over
10 mm of distance, implant size and number should be carefully
considered for avoiding implant overloading. Also, when ridge
position dictates the implant position to be lingual to the tooth
position, buccal cantilevering of the restoration might cause
overloading.
Size of the missing tooth space in relation to contralateral tooth
in the anterior region should be carefully matched for good esthetic
results. Crown/implant ratio should be kept to 1:1 for sound
biomechanics.

13. Diagnosis - Clinical Evaluation
B- Residual edentulous space
Adequate interarch distance (yellow)
More mesio-distal distance than contralateral (green)
Extra width due to rotation of #10 (red)
Buccal cantilevering (red)
might cause overloading
due to off-axial loads.

14. Diagnosis - Clinical Evaluation
C- Adjacent teeth
!
!
!
!
!
Prognosis of the adjacent teeth is very important for avoiding
potential implant failure inflicted from adjacent pathology.
Soft tissue contours and levels should be reviewed to identify any
deficits that might have direct impact on the esthetic outcome.
Position of the adjacent teeth (rotated, tilted, out of curve,
extruded, intruded) along with position of proximal contacts can
cause functional and esthetic problems if not addressed properly.
Wear facets should be carefully analyzed to understand the
occlusal pattern.
Restorations and materials on the adjacent teeth would assist in
designing the optimal implant restoration.

15. Diagnosis -Clinical Evaluation
C- Adjacent teeth
?
?
Prognosis of endodontically treated teeth should be
assessed and pathology should be ruled out. Also,
integrity of the restorations should be examined.
Existence and maintenance of harmonious
gingival levels provide esthetic outcome.
Rotation of #10 decreases papilla height
and causes less than ideal contact
position.

16. Diagnosis - Clinical Evaluation
D- Opposing teeth
!
!
!
Plane of occlusion and occlusion play an important role on the loads
exerted on the implant restoration. Occlusal scheme should be
carefully evaluated for planning the centric and laterotrusive
contacts.
Type of restoration; Fixed would transmit more forces than the
removable restoration.
Prognosis of a compromised tooth might be negatively impacted
when opposed by rigid implant restoration.
Canine guidance
Centric
Protrusive

17. Diagnosis
Study Casts
Edentulous site along with the
adjacent structures can be
analyzed in detail on the casts.
Diagnostic prototype in the missing
tooth site would help visualize the
proposed restoration. Location and
alignment of the proposed implant
can be studied through the
diagnostic work up.
Proposed tooth contours

18. Diagnosis
Surgical Template
It is used for imaging and surgical
purposes. Fabricating a good
template would enhance the
diagnostic value of imaging and
then guide successful placement
of the implant. This template
contains barium sulfate mixed
with clear acrylic at the missing
tooth site for radio opaque
marking during tomographic
imaging.
Proposed implant alignment

19. Diagnostic Imaging
Radiological exam can be done with PA’s and
PAN’s, however, further information can be
obtained via tomograms. Below items are
studied in the radiological exam:
• Pathology at and around the site,
• 3-D bone volume,
• Bone quality through distribution of cortical and
trabecular bones in the proposed site,
• Anatomic structures/restrictions,
• Restoration contours in relation to bone,
• Optimal alignment of implant (perpendicular to
the occlusal plane) within the bone.
Ideal alignment seems to be possible in the facial view (yellow),
however, proposed implant alignment would end up perforating
the buccal plate (red) in the sagittal view. Therefore, implant
axis needs to be redirected within bone (green) which would
cause screw access hole buccally positioned.

20. Time Frame of Traditional Implant
Therapy
Pre-operative
~1 month
(Dx & Tx Plan)
Post-operative
~4-6 months
(First 10-14 days no pressure,
then Tx RPD as interim)
Final restoration
~2 months
(min. 2 weeks soft tissue healing
before impression)
Total
minimum 7-9 months

21. Treatment Planning
Restorative Design
Fabricating the implant template initiates the
restoratively driven implant therapy. This process would
identify restorative concerns and possible
restorative/surgical solutions.
Implant restorations should have similar emergence
profile as natural teeth for establishing and maintaining
esthetic soft tissue architecture. This can be achieved
by proper 3-D placement of the implant.
Biomechanical guidelines:
1. Crown/implant ratio should not exceed 1:1.
2. Implant single crown should not extend lateral to the implant more
than one implant diameter. Narrow occlusal table, using two implants
or wide diameter implant are methods to compensate for potential
overload. (Rangert et al. Forces and moments on Branemark
implants. Int J Oral Maxillofac Implants 1989)

22. Treatment Planning
Restorative Design
Biomechanical considerations: Especially mandibular first molar
sites should be carefully studied, since mesio-distal distance is
usually over 10 mm.
M-D distance measures about 12mm in this
case. Placement of a wide body implant (5
mm diameter instead of 4 mm) along with
narrowing the occlusal plane is intended to
compensate for overloading.
12 mm
5 mm

23. Treatment Planning
Restorative Design
! Biomechanical consideration for first molar site:
M-D >12 mm
Two 4 mm diameter implants were placed in the first molar
site with over 12 mm mesiodistal distance. A splinted
restoration was fabricated by using custom abutments and
screw retained PFM crowns. Note the hygiene access.

24. Treatment Planning
Restorative Design
Occlusal guidelines:
! Light centric contact should be established. Shim stock should only be
grasped when the musculature is fully engaged.
! Eccentric contacts should be avoided. Over-engineering and night
guards are suggested for bruxors.
! Mild cusp heights are preferable since, otherwise bending moments and
load magnification can cause overloading of the implant.
Abutment selection guidelines:
! Screw or cement retained implant restorations can be fabricated. Various
reasons (retrievability, amount of space, esthetics, occlusion, ease of
operation, etc.) can be considered in choosing one over the other option.
However, the decision should be made prior to the placement of the
implant, since position of the implant might be slightly different in each
option.
! The implant restoration should easily be cleansable.

25. Treatment Planning
Surgical Placement
Biomechanical success and restoration/tissue
esthetics depend on the correct positioning of the
implant in the bone. Optimal 3-D position of implant
can be achieved by following below guidelines;
Implant should be centered mesiodistally for
minimizing cantilevering effect and creating normal
emergence profile.
Accurate implant position
provides natural tissue
contours.

26. Treatment Planning
Surgical Placement
Faulty mesiodistal implant placements
Distally placed implant
causes mesial lever arm
when chewing force is at the
mesial. This might initiate
screw loosening and
fracture.
Lack of sufficient space
between the tooth and
the implant resulted in
lack of papilla. There
should be over 1.5 mm
distance between the
natural tooth and the
implant for viable bone
and papilla.

27. Treatment Planning
Surgical Placement
Faciolingual position of the anterior implant
should be aligned under the cingulum of the
proposed crown for screw retained restorations
and under the incisal edge for cement retained
restorations. Posterior implant should be centered
faciolingually for reducing the potential for
overloading.
Implant is centered.
Implant was aligned
under the cingulum for
screw retained PFM
Implant along the
incisal edge for
cement retained PFM

28. Treatment Planning
Surgical Placement
Faulty faciolingual implant placement
The body of the
implant was facially
positioned and
inclined.
Esthetic harmony could not be
achieved due to variations in
gingival levels and teeth lengths.

29. Treatment Planning
Surgical Placement
Incisocervical/occlusocervical position of the
implant is mainly dependent on the location of the
existing bone. However, there is a need to create
emergence profile from implant’s round form to
natural tooth’s elliptical form for achieving natural
esthetics. The head of the implant should be 2-4 mm
below the adjacent gingival margin. Implant template
should represent the CEJ of the proposed restoration
for guiding the surgery.
Diagnostic work up
leads to the implant
template.
2-4 mm

30. Treatment Planning
Surgical Placement
Faulty incisocervical/occlusocervical implant position
This implant has been placed too far
beneath the gingiva.
Result: The depth of the peri-implant is
excessive leading to an increased risk of
peri-implantitis and progressive bone loss
around the implant.
30 months later
Attachment
level
Gingival margin

31. Surgery – Implant Placement
Flap is raised by employing papilla preservation technique for tissue esthetics.
2-4 mm
Osteotomy is oriented through the cingulum for screw retained restoration.

32. Interim restoration
Treatment Removable Partial Denture is worn
following the surgery. The interim prosthesis should
not exert pressure on the site/implant for undisturbed
bone healing around the implant.
Over the healing abutment
Tx RPD should be relieved
underneath the prosthesis
at the time of healing
abutment placement.

33. Implant supported provisional restoration
The provisional restoration is the prototype of the final restoration. It is used
to form the most ideal gingival contours for the definitive crown and also
helps to test and reevaluate the restorative plan. Another use of the
provisional restoration would be to keep it for long term evaluation if the
osseointegration of the implant is questionable.
Screw retained provisional

34. Implant supported provisional restoration
Implant is excessively inclined
towards the facial. Technical
details of the crown fabrication
would be considered at this time.
The screw access hole can be readily
visible at the incisal edge of the
provisional restoration. In this situation
unsupported porcelain cannot be built at
the incisal edge for the final restoration,
therefore restorative decision should be to
make a custom abutment.

35. Abutment selection
The final restoration can be either screw or cement retained.
Various abutments can be used to facilitate the connection between the
implant and the final crown. The UCLA abutment is the most versatile
abutment, since it can be used for both screw and cement retained options.
Screw retained restorations are used when retrievability of the
restoration is desired and minimum incisocervical/occlusocervical height is
available. The single piece restoration uses UCLA abutment and is
screwed onto the implant through the access hole in the cingulum or central
fossa of the crown. This method is used when the position and the
angulation of the implant is ideal. However, a two piece restoration is
used when the access hole exits the crown in an undesirable way. In these
situations a custom abutment is fabricated to accommodate a crown piece
with a lingual set screw. By this way, first piece (custom abutment) gets
screwed onto the implant and the second piece (crown) is screwed onto the
abutment.

36. Screw retained UCLA abutment
restoration (single piece)
Screw access through the cingulum.

37. Screw retained UCLA abutment
restoration (single piece)

38. Screw retained UCLA abutment
restoration (single piece)
#30 was replaced with an implant
restoration. Patient presented with a
healing abutment after second stage
surgery. Impression analog was placed
onto the implant and full seating was
confirmed with a PA. A PFM implant crown
was fabricated and tried in. PA showed
that the PFM was not seated all the way
due to proximal contacts holding (arrow).
After adjustments, implant restoration was
fully seated and the connection screw was
torqued onto the implant with a torque
driver. The access hole was sealed with
gutta- percha and composite on the
occlusal surface.
Tight contacts holding full seating of the crown.

39. Screw retained UCLA abutment
restoration (single piece)
Light centric contact was established while excursive contacts were avoided.
Ideal position of the implant created natural emergence profile which lead to
natural gingival and tooth esthetics.

40. Screw retained UCLA abutment
restoration (two piece)
Resin pattern of the
custom abutment
which changes the
direction of the
implant long axis.
Full contour wax
pattern of a labially
inclined implant.
Completed custom
abutment (first
piece) with lingual
screw access
(arrow).

41. Screw retained UCLA abutment
restoration (two piece)
Metal coping for the second
piece fits over the first
piece.
PFM crown
Screw lapping
Completed and assembled
PFM restoration.
Note the level of the
gingiva.
Retention
screw
Abutment
screw
Custom abutment

42. Screw retained UCLA abutment
restoration (two piece)
Lingual
set screw
Gingival levels do not match but the patient does not
display his gingiva due to low smile line.

43. Abutment selection
The final implant crown can also be fabricated as cement retained
restoration. It is more esthetic especially at the posterior sites due to lack
of screw access hole through the occlusal surface. It can also be argued
that clinical and laboratory procedures for cement retained restoration are
less technique sensitive and similar to conventional crown. However, risk of
leaving cement in the sulcus, not being able to seat the crown due to
hydraulic pressure and increased need for space to accommodate two
piece restoration are disadvantages for this type of implant restoration.
Various abutments can be used to facilitate the connection
between the implant and the final crown for cement retained restorations.
These are all two piece restorations where the first piece is prepared like a
tooth to receive a crown and screwed onto the implant. The second piece is
fabricated just like a conventional PFM crown to be cemented over the first
piece. The first piece can either be custom abutment (using UCLA
abutment) or prefabricated abutment (metal and porcelain) provided by
the implant manufacturer.

44. Cement retained restoration with
UCLA abutment
The UCLA abutment is utilized to fabricate the custom cement-on abutment in the
desired form. Once the custom abutment is screwed and torqued onto the
implant, the screw access hole is sealed with gutta percha. Then the PFM is
cemented permanently in the conventional way.

45. Cement retained restoration with
prefabricated metal abutment
Gingi-hue abutment is provided by the implant
manufacturer to be prepared like a natural tooth
abutment. It is gold color plated to avoid showing
gray hue through the tissue with metal color.
A conventional PFM crown is fabricated on the abutment. First, the abutment is
screwed on the implant and torqued for maximum stability. then the crown is
cemented permanently.

46. Cement retained restoration with
prefabricated porcelain abutment
The prefabricated porcelain abutment is
made from zirconia. It is considered the
most esthetic abutment for the tissue
and the crown. It has no greying effect
on the tissue because of its white color.
For best esthetic results, an all-porcelain
crown can be placed on this abutment.
The zirconia abutment is prepared like a
natural tooth in the laboratory and a high
strength porcelain crown is fabricated.

47. Cement retained restoration with
prefabricated abutment
WARNING: If the margin for the crown is placed very deep subgingival on the
abutment, removal of the excess cement might be difficult during cementation.
A temporary crown was cemented onto the prefabricated abutment. Two
days later note the inflammatory reaction associated with the gingiva
around the crown. These reactions are caused by impaction of cement
into the sulcus upon cementation.

48. The End