Int J Periodontics Restorative Dent 2021;41:227–232

1. The International Journal of Periodontics & Restorative Dentistry
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2. 227
Volume 41, Number 2, 2021
Submitted April 23, 2020; accepted July 7, 2020.
©2021 by Quintessence Publishing Co Inc.
A postextraction socket is always open to different treatment possibilities.
A straightforward clinical classification may help evaluate which surgical
approach is best suited for the case being treated. Four different classes are
defined on the basis of the local anatomy of the site, available bone volume,
and soft tissue level. For every clinical situation, either immediate placement,
early placement, alveolar ridge preservation, or staged approach can be
selected as a treatment modality according to the classifications listed. Int J
Periodontics Restorative Dent 2021;41:227–232. doi: 10.11607/prd.5069
A Clinical Classification System for the
Treatment of Postextraction Sites
1ProEd, Institute for Professional Education in Dentistry, Torino, Italy.
2
Division of Periodontology, Harvard School of Dental Medicine, Boston, Massachusetts,
USA.
3Private Practice, Milan, Italy.
Correspondence to: Dr Daniele Cardaropoli, ProEd Institute, Corso Galileo Ferraris 148,
10129 Torino, Italy. Fax +39-011-323683. Email: d.cardaropoli@proed.it
It is uniformly accepted that the
healing dynamic of a postextraction
alveolus involves the succession of
biologic phenomena. It is initiated
with the stabilization of the blood
clot up to the deposition of a new
bone matrix,1,2
which assists bone
crest remodeling at sites with a loss
of vertical and horizontal volume.3,4
Over time, different classifica-
tions of postextraction sites have
been introduced, each considering
the timing of implant placement
from a strictly chronologic point of
view,5,6
the presence or absence of
the buccal hard and soft tissue,7–9
or the quantity of bone volume
available in relation to the anatomy
and the position of the root of the
teeth.10,11
However, none of the classi-
fications presently available take
into account the anatomy of the
postextraction alveolus and the po-
sition of the overlying soft tissues,
the volume of the bone crest, and
the presence of periapical lesions
and unfavorable anatomical struc-
tures. Furthermore, available classi-
fications do not suggest a possible
therapeutic option for each particu-
lar clinical condition.
Thus, a new classification of
postextraction sites is proposed
based on the anatomical evaluation
of the bone crest and gingival tis-
sues, linking the classifications with
appropriate therapeutic options.
Daniele Cardaropoli, DDS1
Myron Nevins, DDS2
Paolo Casentini, DDS3
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3. The International Journal of Periodontics Restorative Dentistry
228
Extraction Site Treatment
Classes
Postextraction sockets are classified
in four different categories (Fig 1),
and relative surgical treatment op-
tions are suggested. The necessary
information is collected from a care-
ful clinical and radiologic analyses
using both standard intraoral (Fig 2)
and 3D radiographic (CBCT) images
(Fig 3).
Class I: Intact Extraction Site
with Favorable Anatomical
Conditions
Specific characteristics
Characteristics of this classification
include (1) buccal cortical bone that
is intact or affected by damage not
exceeding 20% of the extent of the
wall; (2) an optimum soft tissue level;
and (3) local bone anatomy that al-
lows an ideal tridimensional implant
position and good primary stability.
Surgical treatment techniques
Treatment techniques for this case
include (1) immediate implant place-
ment (potentially combined with
an immediate restoration, if proper
primary stability can be achieved);
(2) alveolar ridge preservation and
delayed implant placement (after 4
to 6 months); and (3) spontaneous
healing and early implant placement
(4 to 8 weeks after extraction) with
bone and/or soft tissue augmenta-
tion.
Fig 1 Schematic drawings of the four different classifications: (a) Class I; (b) Class II;
(c) Class III; (d) Class IV.
a
c
b
d
Fig 2 Clinical images corresponding to the four different classifications. (a) Class I. An
intact socket with a large amount of bone on the palatal side, suitable for immediate im-
plant placement. (b) Class II. An intact socket that apically presents direct communication
with a large nasopalatine canal, which prevents immediate implant placement. (c) Class III.
A compromised socket with the facial bone plate resorbed to almost 50%. (d) A severely
compromised socket, with the facial bone plate resorbed more than 50%, vertical resorp-
tion of the palatal wall, and presence of a periapical lesion.
a
c
b
d
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Volume 41, Number 2, 2021
Class II: Intact Extraction
Site with Partially Favorable
Anatomical Conditions
Specific characteristics
Characteristics of this classification
include (1) buccal cortical bone that
is intact or affected by damage not
exceeding 20% of the extent of the
wall; (2) an optimum soft tissue level;
and (3) difficulty achieving an ideal
implant position and satisfactory
primary stability due to the pres-
ence of a large periodontal defect,
large periapical lesion, and/or ana-
tomical structures limiting immedi-
ate placement (eg, maxillary sinus
floor, mandibular canal).
Surgical treatment techniques
Treatment techniques for this case
include (1) alveolar ridge preserva-
tion and delayed implant placement
(after 4 to 6 months); and (2) sponta-
neous healing and delayed implant
placement (3 to 4 months after ex-
traction) with bone tissue augmen-
tation.
Class III: Partially Compromised
Extraction Site with
Unfavorable Anatomical
Conditions
Specific characteristics
Characteristics of this classification
include (1) resorption of the buccal
cortical bone, totaling 20% to 50%
of the wall; (2) suboptimal soft tissue
level, soft tissues presenting inflam-
mation, and/or thin and scalloped
gingival phenotype; and (3) local
bone anatomy allowing an ideal
Fig 3 CBCT radiologic images correspond-
ing to the four different classifications.
(a) Class I. An intact facial bone plate and
a large amount of bone available apical
and palatal to the root apex. (b) Class II.
An intact and thick buccal bone plate with
a periapical lesion between the root apex
and the maxillary sinus floor, preventing
immediate implant placement. (c) Class III.
Resorption of the facial bone plate and a
large amount of bone available apical and
palatal to the root apex. (d) Class IV. Severe
bone resorption on both the buccal and
palatal sides, together with insufficient api-
cal bone volume.
a
c
b
d
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5. The International Journal of Periodontics Restorative Dentistry
230
tridimensional implant positioning
and good primary stability.
Surgical treatment techniques
Treatment techniques for this case
include (1) alveolar ridge augmen-
tation, possibly with soft tissue
augmentation, and staged implant
placement after 6 months; and (2)
spontaneous healing and early im-
plant placement (4 to 8 weeks after
extraction) with bone and/or soft tis-
sue augmentation.
Class IV: Severely
Compromised Extraction Site
with Unfavorable Anatomical
Conditions
Specific characteristics
Characteristics of this classification
include (1) severely compromised
socket walls, particularly with the
buccal bone wall loss exceeding
50%; (2) suboptimal soft tissue level,
soft tissues presenting inflamma-
tion, or thin and scalloped gingival
phenotype; and (3) difficulty achiev-
ing an ideal implant position and
satisfactory primary stability due to
the presence of a large periodontal
defect, large periapical lesion, and/
or anatomical structures limiting im-
mediate placement (eg, maxillary
sinus floor, mandibular canal).
Surgical treatment techniques
Treatment techniques for this case
include (1) alveolar ridge augmen-
tation, possibly with soft tissue
augmentation, and staged implant
placement after 6 months; (2) spon-
taneous healing, bone augmenta-
tion after 4 to 8 weeks, and staged
implant placement after an addi-
tional 6 months; and (3) spontane-
ous healing and implant placement
after 3 to 4 months, performed si-
multaneously with bone augmenta-
tion.
Discussion
In the literature, there are different
classifications of postextraction sites
based on the timing of tooth extrac-
tion in relation to implant insertion5,6
or the presence of buccal hard and
soft tissues.7–9
Other papers have
called for a sagittal root position (in
relation to the bony housing) during
immediate implant placement in the
maxillary esthetic zone.10,11
The new classification system
presented herein creates a relation-
ship between the socket anatomy
and the soft tissue level and thick-
ness. The main evaluation is based
on the integrity of the alveolus and
gingival level. An intact socket is
defined as presenting three intact
bony walls and at least 80% of the
fourth bony wall.12
For each distinct
clinical situation, more treatment
options are proposed.
When a Class I case is diag-
nosed, the socket is basically in-
tact. The minimum bone volume
needed for implant primary stabil-
ity is related to the surgical skills of
the clinician and the characteristics
of the implant system used, as im-
mediate placement is a technique-
sensitive procedure.13
In the hori-
zontal dimension, creating a bone-
to-implant gap of at least 2 mm be-
tween the implant and the internal
surface of the facial bone wall is rec-
ommended in order to create a suf-
ficient space to be filled with a bone
substitute.14–16
In the vertical dimen-
sion, the implant shoulder should
be placed approximately 1 mm
apical to the midfacial bone crest
to compensate for marginal bone
remodeling.17,18
To optimize esthetic
outcomes, a flapless approach13,19,20
and the delivery of an immediate
restoration is always a suggested
option when possible.21,22
The litera-
ture remains controversial regarding
the need for soft tissue augmenta-
tion in cases of thin gingival pheno-
type.
Following a more prudent ap-
proach, alveolar ridge preservation
(intended as the preservation of the
ridge volume within the envelope
existing at the time of extraction23
)
can be selected as an alternative.
The majority of the original ridge
volume can be maintained when the
fresh alveolus is filled with a bone
graft at the time of tooth extrac-
tion.24,25
Usually, implant surgery can
be performed after 4 to 6 months
with results similar to that of im-
plants inserted in native bone.26
A third option is soft tissue heal-
ing and early placement. An open
flap raised the day of implant place-
ment allows for a contour augmen-
tation using guided bone regenera-
tion.27
For Class II cases, the socket is
still intact, but unfortunately the lo-
cal anatomy of the alveolar ridge
does not allow for an ideal implant
position or good primary stability,
and thus immediate implant place-
ment is not indicated. In this clinical
situation, alveolar ridge preserva-
tion with a staged implant place-
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Volume 41, Number 2, 2021
ment following 4 to 6 months of
healing is suggested. Socket preser-
vation can biologically compensate
for marginal bone remodeling due
to the healing dynamics of the fresh
extraction site.28
When spontaneous healing
is the selected approach, a mean
horizontal ridge width reduction of
3.8 mm and a mean vertical ridge
height reduction of 1.24 mm can be
anticipated.23
This will then require
additional bone augmentation the
day of implant placement.
Class III is characterized by a
compromised extraction socket.
Ridge augmentation (defined as the
increase of the ridge volume beyond
the skeletal envelope existing at the
time of extraction23
) is a valuable
option, with delayed implant place-
ment 6 months later. Alternatively,
early placement can be selected.
Class IV is the least favorable
clinical condition, with a severely
compromised socket and a poor
bone anatomy that is unideal for im-
plant positioning and primary stabil-
ity. In this situation, ridge augmen-
tation can be a suitable approach.
Alternatively, spontaneous healing
and bone augmentation after 4 to
8 weeks (the time needed for com-
plete soft tissue healing and the
resolution of any local infection) is
an option.29
An implant can then be
placed 6 months after augmenta-
tion. A third possibility is spontane-
ous healing and implant placement
after 3 to 4 months (the time needed
for bone tissue healing), performed
simultaneously with bone augmen-
tation.
Conclusions
The clinical classification of postex-
traction sites is a useful, straightfor-
ward, and didactic decisional tool
for evaluating the socket anatomy.
This classification helps determine
a more predictable treatment op-
tion in terms of the timing of implant
placement and the best surgical ap-
proach.
Acknowledgments
The authors declare no conflicts of interest.
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