This article discusses how thick and thin gingival biotypes respond differently to inflammation, trauma, and surgery due to differences in their gingival and osseous architecture. During implant treatment planning, it is important to recognize a patient's gingival biotype as it dictates different procedures for implant site preparation and influences outcomes. Extraction techniques and ridge preservation strategies should minimize trauma to thin alveolar plates associated with thin biotypes to prevent bone resorption and improve implant success. Block grafts may be needed when excessive bone is lost to restore adequate ridge dimensions for implant placement.

1. g i n g i va l b i ot y p e s
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r
Thick vs. Thin Gingival
s Biotypes: A Key
Determinant in Treatment
Planning for Dental Implants
richard t. kao, dds, phd; mark c. fagan, ms, dds; and gregory j. conte, ms, dmd
a bstract During the treatment planning process, it is important
to recognize differences in gingival tissue can affect treatment
outcomes. The concept that thick and thin gingival biotypes have
different responses to inflammation and trauma was previously
introduced. In this paper, this concept is expanded in that gingival
biotypes dictate different procedures for implant site preparation.
With appreciation of these differences, preparatory steps can be
taken to create a more ideal implant placement site.
P
authors acknowledgment reviously, the importance of Thick and Thin Gingival Biotypes
Richard T. Kao, DDS, PhD, This paper is dedicated to
taking into consideration the Historically, Ochsenbein and Miller
is in private practice in Drs. Ivan Ancell and Joseph differences in gingival tissue have discussed the importance of “thick
Cupertino, Calif., associate Zingale who helped guide during treatment planning has vs. thin” gingiva in restorative treat-
clinical professor, the authors during our been emphasized. Specifically, ment planning.1 In a population study,
University of California, periodontal training in the
it was pointed out how thick and thin thick periodontal biotypes (85 percent)
San Francisco, and development and thought
associate adjunct process behind this paper.
gingival biotypes respond differently to were found to be more prevalent than
professor, University inflammation, restorative trauma, and thin scalloped forms (15 percent).3
of the Pacific Arthur A. parafunctional habits.1,2 These traumatic Subsequently, the authors published a
Dugoni School of events result in various types of periodon- paper that further analyzed thick and
Dentistry, San Francisco.
tal defects, which respond to different thin tissue biotypes in terms of their
Mark C. Fagan, MS, DDS,
treatments. The authors also pointed gingival and osseous architecture.2
is in private practice in out how periodontal surgery techniques Thick gingival tissue is probably
San Jose, Calif., assistant have made it possible to change a thin the image most associated with peri-
clinical professor, gingival biotype into a thick gingival odontal health (figure 1a, table 1) .
University of California,
form. This provides a more favorable The tissue is dense in appearance with
San Francisco.
restorative environment and increases a fairly large zone of attachment. The
Gregory J. Conte, MS, the predictability of treatment outcomes. gingival topography is relatively flat
DMD, is in private practice In this paper, the authors extend with the suggestion of a thick underly-
in San Francisco. their earlier observations of thick vs. thin ing bony architecture. Surgical evalua-
gingival tissues and describe why it is tion of these areas often reveals
important to appreciate tissue biotypes relatively thick underlying osseous
during implant treatment planning. forms (figure 1b) .
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table 1
Characteristics of Thick Gingiva
n Relatively flat soft tissue and bony
architecture
n Dense fibrotic soft tissue
n Relatively large amount of attached
gingiva
n Thick underlying osseous form
n Relatively resistant to acute trauma 1 a.
n Reacts to disease with pocket f igure s 1 a - b. The clinical presentation of thick 1 b.
formation and infrabony defect gingiva and the type of osseous architecture associated
formation with this gingival tissue type.
table 2
Characteristics of Thin Gingiva
n Highly scalloped soft tissue and bony
architecture
n Delicate friable soft tissue
n Minimal amount of attached gingiva
n Thin underlying bone characterized by 2a. 2 b.
bony dehiscence and fenestration f igure s 2 a - b. Clinical presentation of thin
n Reacts to insults and disease with gingiva is characterized by thin friable tissue. It is
gingival recession associated with clefts, perforation, and gingival
recession.
table 3
Comparison of Tissue Response to Inflammation, Surgery and Tooth
Extraction
T hick Gingival Biotype T hin Gingival Biotype
Inflammation Soft tissue: Marginal inflammation; Soft tissue: Thin marginal redness
cyanosis; bleeding on probing; edema/ and gingival recession f i g u r e 2 c . The osseous archi-
fibrotic changes Hard tissue: Rapid bone loss tecture associated with this gingival
Hard tissue: bone loss with pocket associated with soft tissue tissue type is characterized by
fenestration and dehiscence.
formation/infrabony defects recession
Surgery Predicable soft and hard tissue Difficult to predict where tissue will
contour after healing. heal and stabilize
Tooth Extraction Minimal ridge atrophy Ridge resorption in the apical and
lingual direction
Thin gingival tissue tends to be tration and dehiscence (figure 2c) . that current periodontal surgical tech-
delicate and almost translucent in ap- In the authors’ previous paper, it niques have the potential to improve
pearance (figures 2a-b, table 2) . The was suggested that since these two tissue quality, thereby enhancing the
tissue appears friable with a minimal tissue biotypes have different gingival restorative environment. The paradigm
zone of attached gingiva. The soft and osseous architectures, they exhibit shift proposed was that by taking into
tissue is highly accentuated and often different pathological responses when consideration the gingival tissue biotype
suggestive of thin or minimal bone subjected to inflammatory, traumatic, during treatment planning, more appro-
over the labial roots. Surgical evalu- or surgical insults2 (table 3) . These priate strategies for periodontal man-
ation often reveals thin labial bone different responses dictate different agement may be developed, resulting in
with the possible presence of fenes- treatment modalities. It also was noted more predictable treatment outcomes.
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Tissue Biotype in Implant Treatment
Planning
If osseous and gingival tissues are dif-
ferent for thick and thin tissue biotypes, f igure 3 a . Tooth No. 9 has a fractured root. f i g u r e 3 b. The crown is removed and the anchor
it seems logical that these distinctions post is placed into the root tip
would significantly influence implant site
preparation and treatment planning. This
is consistent with previous observations
that the stability of the osseous crest and
soft tissue is directly proportional to the
thickness of the bone and gingival tissue.4,5
Thick bony plates associated with thick bi-
otypes and thin plates with potential fen-
estrations and dehiscence associated with
thin biotypes respond differently to ex-
figure 3c. The anchor post is placed through f i g u r e 3 d . The extracted root. This technique is
traction and have a different pattern of os- a perforation in an impression tray containing bite advantageous since there is no force placed on the
seous remodeling following this procedure. registration material. Using the tray as a base, the an- socket and surrounding bone
chor post is ratcheted such that the root is elevated.
The trauma induced by the extraction pro-
cedure is more likely to result in fracture of
the labial plate in the thin biotype than in alveolar plates. Possible strategies contact bite registration and impression
the thick one. Also, the remodeling process that should be considered include: material for the adjacent teeth. After
that follows over the next few months will n Minimizing leveraging forces the impression material has set, the
result in more dramatic alveolar resorp- toward the thin labial plate. Most anchoring device is ratcheted against
tion in the apical and lingual direction for of the manipulation should be fo- the top of the quadrant tray. This strat-
the ridge associated with thin biotypes. cused on the interproximal area. egy is atraumatic and applies no forces
Even after initial alveolar ridge n Sectioning the root(s) from on the surrounding alveolar bone.
remodeling, the gingival tissue and bone the tooth, when possible, to im- Atraumatic extraction and preserva-
are more likely to continue to recede, prove the likelihood for elevation. tion of the alveolar plate are essential
especially if the implant is labially in- n Using periotomes to expand and if the site is to be used for implant
clined. This underscores the importance elevate the tooth with controlled force placement. Excessive force is likely to
of appreciating gingival tissue biotypes focused on the periodontal ligament fracture the alveolar plate and result in
during implant treatment planning. space. The placement and elevation force bone resorption and unpredictable bone
Furthermore, when these tissue bio- should be focused on the interproximal healing. This is more pronounced with
types are carefully considered, various space so leverage force is exerted on the thin alveolar plate associated with
periodontal and surgical strategies can either the buccal or lingual plate. thin gingival biotypes. When compro-
be employed to improve the treatment n Using a ratchet extraction device mise of the alveolar plate is suspected,
outcome either by minimizing alveolar to apply reciprocating force on adjacent it is essential to utilize ridge preserva-
resorption or by providing a better tissue teeth while extruding the amputated tion or augmentation protocols.
environment for implant placement. root tip out the socket (figure 3) . This
may be the most effective and atraumatic Ridge Preservation in Thick vs. Thin
Extraction of Teeth in Thick vs. Thin approach for the broken tooth. The tooth Biotypes
Biotypes is amputated to the level of the cemen- Prevention of postextraction alveolar
Though extractions should al- toenamel junction. After preparation bone loss is critical in assuring implant
ways be atraumatic, teeth with thin of a post space, an “anchoring” device success. Given the thin alveolar plate as-
gingival biotypes merit more atten- is used to engage the root. This device sociated with thin periodontal biotypes, it
tion due to their association with thin is passed through a quadrant tray with is not unusual to see more extensive ridge
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f ig ur e 4a. Lower left lateral incisor No. 23 was f igure 4b . Bone graft material and a resorbable f i g u r e 4 c. Re-entry at five months, which
extracted and extensive bone loss was present. A membrane were placed, (Biomend Extend. Zimmer illustrates bone regeneration up to the top of the
12-mm tenting bone screw was placed to support the Dental. Carlsbad, Calif.) bone screw.
graft material and prevent collapse of the membrane.
remodeling when compared to the thicker to the osseointegration of the dental ramus or mandibular symphysis. Allograft
alveolar plate associated with thick bio- implants. For that reason, slow resorp- block grafts can be obtained from several
types. Not only is atraumatic extraction tion graft materials such as xenografts commercial providers. The advantage of
critical to minimize this postextraction and nonresorbable alloplastic materials this technique is that the graft is placed
remodeling, it is important to consider (durapatite, hydroxyapatite) should be as a block instead of in particulate form,
strategies to preserve the alveolar bone, avoided. When there is excessive volume providing increased structural support.
such as socket preservation or ridge of nonresorbable graft materials, there A case of block grafting is presented
preservation procedures. A number of is inadequate room for bone ingrowth where there is a narrowed anterior
studies have shown that without inter- to provide implant osteointegration. maxillary ridge defect (figure 5a) . These
vention, significant alterations in most Additionally, the ridge preservation situations generally require two-stage
extraction ridge dimensions will occur.6-9 strategy is only successful if the graft ma- surgical procedures that included a bone
This loss can be 1.5 to 2.0 mm over the terial is retained in the extraction socket. graft surgery followed by implant place-
first 12 months with most loss occurring A variety of approaches can be utilized to ment after graft healing. In this situa-
during the initial three months.9 A variety achieve socket closure. These include the tion, it is critical that soft tissue incisions
of approaches can be employed to address use of barrier membranes, tenting pins, be carefully planned to allow for flap
this problem, but most involve grafting collagen plugs, connective tissue grafts, relaxation over the increased volume
the extraction socket and using mem- free gingival grafts, acellular dermal gained by the graft and to ensure ten-
branes to support missing/perforated grafts, and advancement of the buccal sionless primary closure. Once adequate
bony walls. Ridge preservation should flap. An advanced case of socket preserva- access was gained, the graft and recipient
be considered for most thin biotype tion with regeneration of the labial plate bed were prepared to obtain intimate,
cases and in thick biotype cases where and vertical dimension is seen in figure 4 . broad contact between the surfaces.
excessive trauma or a previous history Whereas simple cases with intact buccal The recipient bed was perforated to
of endodontic surgery/fistula tracts may and lingual plates can be easily man- enhance revascularization and the graft
have compromised the alveolar plate. aged with grafting and socket coverage, was stabilized using fixation screws to
Classically, socket or ridge preserva- advanced cases may require space-main- maintain close bone contact and prevent
tion involves the use of a graft material taining devices such as tenting pins and graft rotation (figure 5b) . Adequate prima-
placed in the socket followed by a variety membranes. All of these options work to a ry fixation is essential for graft survival.
of other substances such as demineralized certain extent and the selection should be Particulate bone can be packed around
freeze-dried bone allograft, mineralized based on individual cases/requirements. the block and a resorbable collagen
freeze-dried bone allograft, xenograft When excessive bone is lost to membrane can be placed over the entire
(mostly of bovine source), and alloplas- resorption, leaving a narrow ridge with graft. The soft tissue flap is then advanced
tic materials (b-tricalcium phosphate, a large buccal deficiency or decreased and sutured for primary closure. After
durapatite, hydroxyapatite). Since the site vertical height, a block graft is gener- a healing period of five to six months,
will be used for implant placement ap- ally the technique that yields predict- the site can be re-entered and integra-
proximately three months to four months able results.10-11 The block graft material tion of the graft to the recipient bone
after grafting, it is important to select a can be of autologous or allograft origin. confirmed. Using an appropriate surgi-
graft material that resorbs quickly since Autologous graft material is commonly cal stent, implants can then be properly
only newly formed bone will contribute harvested from either the mandibular placed into the widened ridge (figure 5c) .
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f ig ur e 5a. Extensive defect noted upon flap f igure 5 b . The area was prepared and a block f i g u r e 5c. Re-entry at six months. Note the
elevation. allograft was trimmed and fixated with two bone excellent ridge width obtained and the ideal
screws (J Block Cortico-Cancellous Bone Allograft, implant placement in the augmented site.
Zimmer Dental).
pulled coronally, possibly resulting in
a lack of adequate attached tissue, and
thereby creating a “thin” case that will
compromise future implant placement.
A technique for covering the socket
after tooth extraction using a pediculated
connective tissue graft was described by
Mathews.12 Utilizing this closure tech-
nique over the grafted socket permitted
complete soft tissue coverage. Addition-
figure 6a. The initial defect after tooth extraction. f igure 6 b. The defect was filled with FDBA and ally, it maintained both vertical and
The defect is mainly a three-wall defect with almost a tenting pin was placed for space maintenance.
horizontal soft tissue components, and
complete loss of facial bone.
increased the thickness of facial attached
tissue (figure 6c) . After healing for five
to six months, the site was re-entered
and an implant was placed (figure 6d) .
This case illustrates the transformation
of a severely “thin” defect into a more
advantageous “thick” periodontium.
Immediate Implants in Thick vs. Thin
Biotypes
Whether a practitioner chooses to
f ig ur e 6c. A pediculated connective tissue graft f igure 6 d . On re-entry, there is both adequate
was used to cover the grafted defect, maintaining volume of hard, as well as soft, tissue for implant place an implant as a delayed or immedi-
soft tissue height and width. placement. ate treatment will depend on the condi-
tions of each case. A delayed implant
In this second case of deficient alveo- space, a tenting pin was placed in the approach might be taken when there
lar ridge, it is essential to rebuild both socket in an orientation to help support is not enough thickness in periodontal
the hard and soft tissue components in a both the facial and vertical dimensions. tissues to predictably minimize alveolar
single procedure to improve the esthetics Particulate freeze-dried bone allograft resorption secondary to healing, or a lack
and to minimize surgical visits (figure 6a) . material was packed into the socket of anchoring bone to ensure stabilization.
This case illustrates a three-wall defect, around the tenting pin, slightly overfill- The decision is also dependent on the
which has better regenerative potential ing the defect (figure 6b) , and a resorb- practitioner’s comfort level in available
than the one-wall type discussed previ- able collagen membrane was trimmed reconstructive techniques. For a thin
ously. For this defect, particulate bone can and placed over the graft material. biotype case, practitioners must be aware
be used as long as two critical compo- Soft tissue closure over the mem- of the possibility of significant resorption,
nents of regeneration are included: space brane and graft is critical for proper which may have an impact on esthetics.
maintenance and adequate soft tissue healing. If the facial flap is advanced over Furthermore, the loss of peri-implant
closure. In order to maintain the defect the defect, the vestibular tissue will be structures may result in thin, trans-
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6. g i n g i va l b i ot y p e s
c da j o u r n a l , vo l 3 6 , n º 3
tion and provide a more favorable tissue
environment for implant placement. This
is especially important in thin periodontal
biotypes where the thin alveolar plate is
highly susceptible to remodeling. Addi-
f ig ur e 7 a . Initial presentation of maxillary left f igure 7 b . Incisal view of immediate implant tionally, these techniques when appropri-
central with fractured root. Relatively minor facial placement after tooth extraction.
inflammation and recession are present.
ately applied can save on treatment time
and cost for patients.
f igure 7 c .
Radiograph of r e f e r e nce s
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determinant in tissue response to disease and restorative
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als with varying forms of the upper central incisors. J Clin
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appears grayish, especially if the facial that called for extraction of the tooth and dontol 50:170-4, 1979.
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In a thick biotype environment, imme- to exposure of the implant. The implant ing tooth extraction. J Prosthet Dent 17:21-7, 1967.
9. Schropp L, Wenzel A, et al, Bone healing and soft tissue con-
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ate implant placement may be necessary in treatment planning. Since thick and nique for improving unaesthetic implant restorations. Pract
Proced Aesthet Dent 14(9):719-24, 2002.
to achieve the best esthetic outcome. thin gingival biotypes are associated 13. Sammartino G, Marenzi G, et al, Aesthetics in oral implan-
Proper treatment planning between with thick and thin osseous patterns, tology: biological, clinical, surgical, and prosthetic aspects.
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14. Dennison HW, Kalk W, et al, Anatomic considerations for
dentist is essential when optimal esthetic ferently to the trauma of extraction preventive implantation. Int J Oral Maxillofac Implants 8:191-6,
results are desired. An illustrative case is and have different patterns of osseous 1993.
a patient presented with a fracture in the remodeling following the procedure.
root of the maxillary left central incisor By understanding the nature of the to request a printed copy of this article, please con-
tact/ Richard T. Kao, DDS, PhD, 10440 S. DeAnza Blvd., Suite
(figure 7a) . After appropriately evaluating tissue biotype, the practitioner can employ D1, Cupertino, Calif., 95014.
periodontal tissue characteristics and oth- appropriate periodontal and surgical
er necessary surgical and restorative infor- procedures to minimize alveolar resorp-
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