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Timing, Positioning, and Sequential
Staging in Esthetic Implant Therapy:
A Four-Dimensional Perspective

Akiyoshi Funato, DDS*
Maurice A. Salama, DMD**
Tomohiro Ishikawa, DDS***David A. Garber, DMD**Henry Salama, DMD****

Many articles address the predictability of immediate implant placement into
extraction sockets; however, there are only a few reports that mention the indications and limitations of this technique. The aim of this article is to re-examine
specific indications for immediate implant placement and to clarify the timing or“fourth dimension” relative to extraction and implant placement. The expanded
concept of four-dimensional implant treatment planning involves the new axisof time, which must be considered along with the traditional spatial or threedimensional management of implant positioning. (Int J Periodontics Restorative
Dent 2007;27:313–323.)*Private Practice, Kanazawa, Ishikawa, Japan.
**Clinical Assistant Professor, Department of Periodontics, University of Pennsylvania,
Philadelphia, Pennsylvania; Medical College of Georgia; Private Practice, Atlanta,
Georgia.
***Private Practice, Hamamatsu, Shizuoka, Japan.
****Clinical Assistant Professor, Department of Periodontics, University of Pennsylvania,
Pennsylvania; Private Practice, Atlanta, Georgia.
Correspondence to: Dr Maurice Salama, 600 Galleria Parkway, Suite 800, Atlanta, GA,
30339; fax: +404-261-4946.

The key to successful implant therapy
in the anterior esthetic region is a harmonious relationship between theimplant-supported restoration and theremaining natural teeth. The creation ofa natural-looking implant restoration
depends not only on the appropriate
placement of an osseointegrated
implant and restoration, but also on
the reconstruction of a natural gingival
architecture around the implant that isin harmony with the lip line and face.
To achieve this goal, an implant must
be conceptually planned and placed asa vertical extension of an optimally visualized restoration, as described by
Garber and Belser in their concept of“restoration-driven implant treatment
planning.”1,2 This approach involves
three-dimensional (3D) treatment planning, followed by placement of theimplant in a position that is optimal forboth function and esthetics. The initial
3D evaluation of the potential site must
include planning for augmentation orpreservation of the existing osseousand gingival tissues around the compromised tooth. This should be an integral part of the process, because it is
known that extraction is always followed by some bone resorption, with

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concomitant soft tissue recession.3–5
To achieve the optimal esthetic result,clinicians must go beyond using themost appropriate clinical techniques
and armamentarium and must consider a fourth dimension: timing of thetreatment sequence. This additional
component in treatment planningincorporates the optimal sequential
staging or timing of (1) tooth extraction,(2) preservation or enhancement of
hard and soft tissue, (3) implant placement, (4) abutment connection, (5) tissue modeling with a provisional and/ora modified abutment, and (6) definitive
restoration. This additional axis of timeis added to the traditional 3D axes anddescribed herein as the four-dimensional (4D) concept in implant therapy.
Successful esthetic implant therapy, then, has several sequential
objectives:
1. Restoration-driven 3D implant
replacement, ie, placement of theimplant in the optimal position toeffectively support the restorationand surrounding soft and hard tissue
2. Any necessary reconstruction ofan esthetic gingival soft tissue
frame incorporating the harmony
or curvature to the labial free gingival margin aspect of the restoration with the definitive vertical andbuccolingual presence of adjacentinterdental papillae
3. A provisional restoration to maintain or modify the degree of curvature of the labial free gingival
margin and provide the necessary
lateral support for the interproximal papillae
4. Placement of a definitive restoration that is in harmony with theadjacent natural teeth and surrounding soft tissue, with identicalgingival color
The actual timing of tooth extraction, implant placement, and abutment
connection will ultimately influence thespecific outcome by limiting the number of individual auxiliary procedures
while enhancing predictability.
Conceptually, then, it reduces thepotential number of surgical/restorativeinterventions, shortening the treatment
span and thereby enhancing esthetic
predictability. Immediate implant
placement has been well documented
in the literature, and the data indicate
similar predictability versus the staged
approach.6–11 Ongoing improvements
in resorbable membranes have helped
expand the potential indications for
immediate implant placement withdecreased complications during
guided bone regeneration (GBR).
Today, there is still a dichotomy ofthought regarding the timing of extraction and implant placement, and it is
the authors’ contention that no single
method is a panacea; rather, there are
specific clinical indications for each.
The aim of this article is to re-examine
specific indications for immediate
implant placement and to clarify thetiming or fourth dimension relative to
extraction and implant placement. The
expanded new concept of 4D implant
treatment planning involves time,
which must be included with the traditional spatial or 3D management of
implant positioning.
The timing of tooth extraction andimplant placement is classified asfollows:• Class 1: Extraction, with immediate
implant placement directly into thealveolar socket via (a) “incisonless”
implant placement or (b) the raising of a mucoperiosteal flap andplacement of the implant into theextraction socket concomitant witheither (i) osseous augmentation or
GBR or (ii) a connective tissue or
allograft.
• Class 2: Early implant placement.
The implant is placed after extraction, and soft tissues are allowed toheal for 6 to 8 weeks. GBR can be
performed at the time of extraction
and/or at the time of implant
placement.
• Class 3: Delayed implant placement. The implant is placed a minimum of 4 to 6 months after extraction, with preservation of thealveolar ridge using grafting techniques and/or GBR, either at thetime of extraction or concomitantwith implant placement. Soft tissuereconstruction in these cases willinvariably be required.
Based on this classification, a tooth
targeted for immediate implant placement should be diagnosed as nonsalvageable for the following reasons: (1)endodontic failure, (2) internal and/or
root resorption, (3) subcrestal extensive caries, or (4) root fracture.
Conceptually, the targeted toothdemonstrates no osseous compromise; clinically, the bone on the immediately adjacent teeth should be evaluated as to the relative height of theinterproximal height of bone (IHB),12,13
since it is this IHB on the adjacent tooththat effectively determines the absenceor presence of a natural papilla.

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It has been determined that a distance of 4.5 mm from the desired contact point, or from the tip of a papillato the peak of the interproximal heightof bone on the teeth adjacent to theimplant site, is the mean dimension
for the predictable presence of a “full”
papilla.12 Immediate implant placement into these types of extraction
sockets with four walls shows better
esthetic predictability than the replacement of teeth with periodontal compromise. If the targeted tooth or any
adjacent tooth shows an IHB with adistance in excess of 4.5 mm, thendelayed placement is preferable, withpreemptive orthodontic treatment of
the tooth to be extracted or subsequent orthodontic treatment of theadjacent teeth to ensure esthetic predictability. In many cases, orthodontic
eruption, as a preliminary step to
extraction with immediate implant
placement, even in a type 1 site, provides the clinician the esthetic andmechanical advantages of added
osseous support to compensate forthe bone loss inevitable with extraction. This is particularly necessary in
Asian patients, who often haveextremely thin labial plates of bone in
the maxillary anterior region. In thesethin scalloped biotypes, even thougha thin labial alveolar bone is present following implant placement, 1 to 3 mmof gingival recession invariably occurs
over time following the connection of
the abutment because of remodelingof the hard and soft tissues around
implants.14–16

Orthodontic extrusion
Salama and Salama17 reported on theadvantages of orthodontic eruption asa preliminary step to implant placement. These include the following:
1. It decreases or minimizes the“gap” between the implant bodyand the extraction socket by coronally relocating a narrower portion of the root for extraction andtherefore resulting in a smallerdiameter socket.
2. It helps enhance primary stability
in the alveolus by developing thealveolar bone beyond the root
apex.
3. It augments the crestal alveolarbone and overlying gingival tissues, decreasing the negative
impact of postoperative alveolar
resorption and gingival recession.
4. By loosening the tooth, it helps
facilitate extraction.
5. It increases the mitotic turnover ofthe cells in the region, enhancing
the potential for more rapid healing.
Orthodontic eruption should be
used to generate at least 2 mm ofadditional vertical gingival tissue ascompared to the adjacent teeth to provide for a harmonious gingival arrangement. After a 12-week period of retention, the alveolar osseous crest on the
facial and interproximal aspects is confirmed by bone sounding. In addition,
a computerized tomographic scan canbe performed to evaluate whether
there is sufficient bone available tofacilitate extraction with immediate
implant placement without resultant
esthetic compromise.

Potential or future extraction sites
are now routinely augmented vertically by orthodontics from a class 2 toa class 1 site (based on the classification system described in next section)
when needed.

Classification of immediate
implant placement sites
The classification detailed below andin Table 1 is based on both the osseousand soft tissue levels of the potentialsite at the time of extraction.
• Class 1: The buccal bone is intact,with a thick gingival biotype.
“Incisionless” implant placement
without flap reflection is viable (Fig 1).
• Class 2: The buccal bone is intact
with a thin, more scalloped gingival biotype. Incisionless implant
placement is viable, but in combination with a connective tissue
graft or a subsequent secondary
connective tissue graft (staged)(Fig 2).
• Class 3: The buccal bone is lost,
but the implant can still be placed
immediately within the remaining
alveolar housing of the extraction
socket, with the necessary osseous
support provided through regeneration using a membrane with
GBR and incorporating a simultaneous connective tissue graft.
Depending on the degree of compromise to the buccal plate, thecase may alternatively be handled
in a staged approach using asocket augmentation procedureand subsequent implant placement. In many instances, especially

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Table 1Class
Class 1
Class 2
Class 3

Class 4

Classification of immediate implant placement

Buccal bone
Intact with thickgingival biotype
Intact with thingingival biotype
Deficient but implant
placement possible inremaining alveolar housingof extraction socket
Deficient andimplant may deviate
from alveolar housing

Viableimplant placement
technique

Expected resultsof immediate
implant placement

Indication for
immediate
implant placement

Immediate without
flap reflection
Immediate with
CTG or staged CTG
Simultaneous
immediate with GBR
and CTG or followed
by staged CTG
DelayedOptimal

Yes

Good

Yes

Acceptable

LimitedUnacceptable

No

CTG = connective tissue graft.

Fig 1a (left) This case is categorized asclass 1. Following orthodontic extrusion, themaxillary left central incisor was extracted.
The existing buccal bone was confirmed bybone sounding with a periodontal probe. A
thick biotype was diagnosed.
Fig 1b (right) An implant was placed “incisionless” without flap reflection, and a provisional restoration was placed immediately.

Fig 1c (left) Facial view of the definitive
implant analog and definitive abutment. An
abutment access hole cannot be seen, confirming that the extended long axis of theimplant would not be labial to the incisaledge of the restoration.
Fig 1d (right)
restoration.

Facial view of the definitive

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Fig 2a (left) This case is categorized asclass 2. At the initial examination, an amalgam tattoo and root fracture were evident
at the maxillary left central incisor.
Fig 2b (right) The amalgam tattoo tissue
was surgically excised, and a subepithelial
connective tissue graft was placed.

Fig 2c (left) Orthodontic eruption of the
tooth intended for extraction was performed; following confirmation of theresulting bone level, both interproximallyand labially, the tooth was extracted withthe aid of a periotome.
Fig 2d (right) Surgical guide in position
prior to implant placement. The implant
was placed, and an immediate provisional
restoration, employed for both immediate
esthetics and to provide optimal support forthe soft tissues, was placed.

Fig 2e (left) Facial view of the definitive
restoration on the maxillary left central
incisor. A diminished or concave labial contour and positive interproximal support
maintain the form of the free gingival margin and the height of the papillae.
Fig 2f (right)
1 year.

Postoperative radiograph at

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Fig 3a This case is categorized as class 3.
Extraction with immediate implant placement was performed despite compromise
to the buccal bone, but the implant was
retained within the confines of the alveolar
housing.

Fig 3b Connective tissue grafting in combination with GBR was used, incorporatinga resorbable membrane. The connective tissue graft was used to optimize the esthetic
soft tissue profile.

Fig 3c Facial view of the definitive
restoration. While an “adequate” esthetic
outcome was achieved, a small depression
is evident in the buccal cervical region.

in thin biotypes, this method provides a more predictable and safer
outcome (Fig 3).
• Class 4: The buccal bone is severelycompromised, and implant placement within the remaining palatalbone results in a significantly offaxis implant position. In these cases,
following extraction, implant placement should be delayed. If performed immediately, the long axisof the implant inclines toward the
buccal and will result in a significant
esthetic compromise of the definitive restoration. In these situations,the delayed approach should be
used with subsequent 3D bone andsoft tissue augmentation of the deficient ridge followed by optimal
implant positioning.

ing the restorative esthetics. The longaxis of the implant should be placed lingual to the incisor edge whenever possible to allow for both mechanical andsurgical advantages in the definitive
outcome. The lab will have more space
to work with porcelain and to hide theprosthetic components, the restorative
clinician will have more room to establish a proper emergence profile, andthe surgeon will have less pressure
placed onto the labial tissues.

long axis of the implant is inclined labially and projects beyond the incisaledge of the definitive restoration, theresult is that the subgingival contoursof the abutment or restoration will tend
to deflect the gingival margin apically,
resulting in an unharmonious esthetic
profile.18 To correct this problem, theprofile extending from the implant
head to the free gingival margin
requires a straight or negative angulation. Immediate placement generally
cannot be performd in the wrong position without esthetic compromise.

In evaluating a potential site, caremust be taken to ensure that the clinician’s attempts to expedite implant
placement within the available bone
do not result in an implant that tends to
extrude labially, thereby compromis-

The platform of the implant should belocated 2 to 4 mm below the midfacialaspect of the free gingival margin, withthe extended long axis directedslightly lingual to the incisal edge of thedefinitive restoration (Fig 4). When the

Implant positioning, theresulting long axis, and soft
tissue considerations

Vertical depth of implant headand direction of long axis

Buccolingual position and labial
regionTarnow et al19 stated that a submerged
implant, following abutment connection, will develop a vertical change in theosseous topography of 1.5 to 2 mm
below the implant shoulder. In addition,
circumferentially, or horizontally, this will
create crater-shaped or horizontal/lateralbone resorption of 1.3 to 1.4 mm.16

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Fig 4 Examples of the positions of immediately placed implants following orthodontic extrusion. These positions are classified
based on both the osseous and soft tissuelevels at the potential site at the time ofextraction. Ideally, the implant engages thepalatal wall of the extraction socket, and theextended long axis is directed slightly lingual to the incisal edge of the definitive
restoration. Immediate placement generally
cannot be performed in the wrong position
without esthetic compromise.

Grunder et al20 stated that at least 2
mm of lateral alveolar bone must bepresent beyond the body of the implant
to compensate for the effects of bone
remodeling. In the case of extraction
with immediate implant placement, an
implant should be placed lingually,
avoiding the coronal 5 mm of labial
bone and allowing for a gap of less than
2 mm, measured laterally from theperiphery of the implant to the labial
aspect of the socket. Grunder et al indicated that to support the gingival profiles, at least 2 mm of bone are necessary at the head of the implantmeasured laterally to allow for sufficientbone to remain in the esthetic position
despite the naturally occurring horizontal cratering. Therefore, in any extraction
with immediate implant placement,
despite the necessity of maximizing the
gap at 2.2 mm,21 it may be necessary toincrease the size of this gap and actuallyrefill it with a grafting material.7,22 This
will ensure that, following horizontalbone remodeling, 1.5 mm of bone will
still remain lateral to the buccal aspect

Ideal position

Acceptable positionsof the extraction socket following
resorption to support the vertical heightof the soft tissue. Implant designs thatreportedly minimize crestal bone loss asa result of the abutment connection
have recently been suggested.23–25
Elimination of abutment-to-implantmicromovement, development of ahermetic bacterial seal, or the use of“platform switching” (smaller abutment
with wider implant platform) could
make esthetic implant treatment—
particularly with adjacent implants—
more esthetically predictable.24,25
However, the data on these potential
solutions are still being evaluated.
Maynard and Wilson26 related therisk of potential gingival recession to
the gingival biotype and underlying
alveolar bone. They indicated that abiotype with thin gingival tissue andthin alveolar bone has the highest riskof gingival recession.26 Kan et al27
reported that the thick gingival biotype has a more coronal level of gingival margin, with greater predictability than thin gingival biotype. It is

Wrong position

evident, then, that prior to implant
placement, a thorough evaluation of
the periodontal biotype is necessary;with the thin biotype, connective tissue
grafting may be necessary to reduce
soft and hard tissue compromise.

Mesiodistal position relative tothe interdental zone
The head of an implant is positioned
relative to the osseous on the direct
labial; depending on the implant system used and particular philosophy, itis placed level or just coronal to it, oreven slightly below the midcrestalbone. Of necessity and because of theflat head design of most implant systems, the interproximal aspect will
extend well below the interproximalheight of bone. This distance will varywith the periodontal biotype, ending
up considerably deeper in the scalloped as opposed to the flat biotype.
Salama et al12 have developed a classification system for the predictable

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Fig 5a (left) Classification of interproximalbone height (IHB). 1 = Optimal result; IHB 2
mm from the cementoenamel junction (CEJ)and 4 to 5 mm from contact point. 2 =Unfavorable result; IHB 4 mm from CEJ and
5 to 7 mm from contact point. 3 = Severe
result; IHB > 5 mm from CEJ and > 7 mmfrom contact point.

3
2
1

Fig 5b (right) Apical extent of the contact
point (A), IHB on the natural tooth (B), and
IHB on the implant (C).

C

Salama et al12 classification of predicted height ofinterdental papillae

Class

Restorativeenvironment

Proximity
limitations

Vertical soft tissue
limitations

1
2
3
4
5
6

Tooth-tooth
Tooth-pontic
Pontic-pontic
Tooth-implant
Implant-pontic
Implant-implant

1.0 mm
N/A
N/A
1.5 mmN/A
3.0 mm

5.0 mm
6.5 mm
6.0 mm
4.5 mm
5.5 mm
3.5 mmheight of the interdental papillae, as
determined by the restorative elements on either side of the implantsite (Table 2, Fig 5). The six classifications are differentiated by whether apapilla has a tooth, a pontic, or an
implant on either side of it. Their data
indicated that the vertical height fromthe tip of the interdental papillabetween two implants was in excess of
2 mm less than that between an
implant and a pontic; this resulted in amuch shorter papilla and a longer
restorative contact point.12 This classification system and its associated treatment planning algorithm allow the clinician to prognostically plan for esthetic
soft tissue contours by selecting themost appropriate fixed restorative
option based upon the available vertical bone support.
The numeric values just described
may well be a result of the difference inthe attachment modality of soft tissue
in the natural tooth or pontic as
opposed to the implant, in combination with the result of the remodeling of
the peri-implant bone following abutment connection. The Salama et al12classification also described the horizontal dimension necessary between
the restorative elements to facilitate
the predictable presence of a papilla—
for instance, the implant-to-implant
dimension should, at a minimum, be 3
mm, whereas the necessary dimension

3.5
mm

B
4.5 mmA

Table 2CCA

between an implant and a tooth can beconsiderably less, at only 1.5 mm.20,28
It is their contention that, with the present design of implants, the use of apontic between implants improves therelative height of the papillae and theoverall esthetic gingival outcome.23–25
Evolving changes in implant design,
such as the single-body design or a
two-piece implant system with a biologically “invisible” connection, may
decrease the potential for crestal bone
remodeling and resultant soft tissuechanges. In addition, it appears fromthe work of Abrahamson et al29 thatevery incident of abutment connection
and disconnection enhances theprocess of bone remodeling.

The 4D concept in complex
cases
In multiple-implant cases associatedwith bone defects (Fig 6), the use of
strategically timed serial extractions is
exceedingly important to support a
fixed provisional restoration duringridge reconstruction and implant site
development. Key abutments are
selected at optimal positions to sup-The International Journal of Periodontics & Restorative Dentistry
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Fig 6a Case 4. Preoperative facial view.
The maxillary anterior teeth show collapseof the supporting bone.

Fig 6d Implants were placed in the positions of the right first molar, right first premolar, right central incisor, and left canine withsinus augmentation and GBR. The right central incisor site was an immediate placementsite categorized as a class 3. At the rightcanine site, which was categorized as class 1,
extraction and immediate implant placement were postponed until the previously
placed implants were integrated and placed
into function in the provisional prosthesis.
The implant was placed toward the palate tosecure a full 2 mm of distance from the labialbone. It was determined that if the existing
contour was maintained, the IHB presented
a high potential to preserve the papillabetween the implants.

Fig 6b The left central and lateral incisors
exhibit bone resorption beyond the apex.

Fig 6c Three-dimensional image using
computer simulation software exhibits thehorizontal and vertical bone defects in theanterior region.

Fig 6e Lateral view of the right side after
definitive cementation. In the canine area,
implant placement allowed for the preservation of the tissue around the implant. Thisnatural-looking outcome was achieved byusing the 4D concept.

Fig 6f The definitive result. A moderately
natural appearance was obtained andacceptable interdental papillae maintained.

Fig 6g Postoperative periapical radiographs. The bone crest between the maxillary rightcanine and first premolar was maintained at a higher level than the horizontal platform of theimplant. The appropriate interproximal height of bone was retained in the implant region.

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port a splinted full-arch provisional
restoration while the ineffectual teeth
are extracted and hard and soft tissues are reconstructed; implants arethen placed. Following osseointegration, these implants are in turnused to support a new provisional
restoration or incorporated into theexisting provisional.
The decision needs to be madeon a tooth-by-tooth basis as towhether the remaining teeth that previously supported the provisional
should be extracted and made into a
pontic site with socket preservation
techniques or sectioned below the
crest of the ridge and below a connective tissue graft to preserve or redevelop the soft tissue esthetics. During
implant placement, these key natural
abutment teeth are used as guides tothe vertical potential for augmented
tissues as well as to the level of vertical placement of the implant. The preexisting IHB on these remaining teeth
is the limiting factor in the soft tissue
potential for an esthetic restoration.
Obviously these key abutments need
to be relatively stable to support therestoration. These provisional abutment teeth demonstrate the key roleof the fourth dimension of time in 4D
implant therapy, as the relative timingof the extractions is obviously a key
component in predictable implant
treatment planning.

Conclusion
A correct understanding of the indications and classification for immediate
implant placement will dramatically aid
the clinician in determining an appropriate treatment plan and time frame
for individual tooth extractions andimplant placement in single implant
cases as well as complex multiple
implant cases. This expansion of the3D “spatial” placement of implants
into a 4D concept uses timing as a key
variable in the development of esthetic
implant restorations.

Acknowledgments
The authors would like to thank Dr Myron
Nevins and Dr Yoshiro Ono for their encouragement and support.

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COPYRIGHT © 2007 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF THISARTICLE MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER