Departments
MICROSURGERY
Nov/Dec 2008 —
Vol. 2,
Iss. 5
Periodontal Plastic Surgery I: Root Coverage
Michael Sonick, DMD; and Debby Hwang, DMD
A smile is one of the most primitive forms of human
communication, and it is not surprising that
an esthetic one is the major ambition of
patients. Face-lip, lip-tooth, and lip-gingiva relations all determine the appeal of a smile. The amount of
tooth structure exposed during smiling depends on a number of factors: the
degree of contraction of the muscles of facial expression, soft tissue level, skeletal characteristics, and the design
of restorations, tooth shape, or tooth wear.
Most people fail to expose much of the
gingival tissue during smiling but those with a
short upper lip, hypermobile lips, or large alveolar processes often do.1 Excessive gingival display occurs in patients
with a moderately long upper lip only in the presence of unusual maxillary
anterior supra-eruption or skeletal hyperplasia.
THE PERFECT SMILE
Three general classifications of smile lines exist,
based on the height of the upper lip relative
to the maxillary anterior central incisors:
high, average, and low. A high smile exposes the total length of the maxillary anterior teeth and a contiguous band of gingiva.2 An average smile exhibits 75% to 100% of the teeth and the interproximal gingiva only, while a low smile displays
less than 75% of the anterior teeth. Roughly
70% of people have an average smile, 20% have a low smile, and 10% have a
high smile. Men present more frequently with low smile lines, though
perhaps this mirrors conformity to masculine archetypes.
THE PERFECT GUMS
The clinician cannot underestimate the
magnitude of the periodontal drape
in the look of a smile. The gingiva frames the teeth, and its position, shape, and color establishes an esthetic
facade. Ideally, the gingival margin of the
maxillary lateral incisors lies 1 mm to 2 mm
incisal to that of the central incisors and
canines.3 The height of contour of the gingival margin of maxillary central incisors and canines occurs at the distal
line angle; alternatively, the lateral
incisor’s height of contour exists at the
mesiodistal center.4
Tissue thickness and tooth shape govern the degree of
gingival scallop. Thick tissue and square-shaped teeth support a flat
gingival contour (more masculine), while thin tissue and triangular teeth
favor a scalloped margin (more feminine).5 Papillae fill the embrasure
spaces in healthy patients, after the morphology of the intact underlying
bone. In the anterior region, papillae appear convex, reduced in width, and pyramidal or knife-edged. Papillae become flatter between posterior teeth. Healthy gingiva
appears pink, with possible stippling, and entirely covers the
cementum. The epithelial attachment of the gingiva to the tooth should lie at the cementoenamel junction (CEJ) or immediately above.
HOW TO ACHIEVE GINGIVAL BEAUTY
Patients often complain about smiles that expose
“too-long teeth.” These unsightly
issues may stem from a flawed gingival drape.
A “mucogingival deformity” arises when there exists a significant departure from the normal shape of the soft
tissue, with or without bone loss. Examples
include recession and altered passive
eruption—basically too little and too much tissue, respectively. To correct such deviations from the norm, periodontal plastic surgery is performed, including grafts for
root coverage as well as esthetic crown
lengthening.
The following sections of this article address how to
diagnose and what to do in cases of exposed roots due to insufficient gingiva. A future article will discuss the opposite
scenario: a surplus of tissue.
DEFICIENT GINGIVAL TISSUE
Buccal or lingual recession exists when the
anatomical root becomes visible and
exposes cementum. A related or separate entity,
papillary recession occurs when the interdental tissue falls short of the contact point.6 Many therapies exist to cover root surfaces with success; papilla regeneration, on the other
hand, is a much more unpredictable
undertaking.
The prevalence of recession elevates with age; 90% of
people 80 to 90 years old have at least 1 mm
of exposure.7 Recession typically
occurs on the buccal in males and in African-Americans, and on maxillary canines, premolars, and first molars along
with mandibular central incisors in other
individuals. Indications to treat recession
involve esthetic disharmony, clearly, but include hypersensitivity and
defect progression as well.
Treatment of defects first concerns the arrest of
any etiological factors (Figure 1 View Figure); success
relies on choosing suitable cases to treat.
Miller classified recession based on the relationship between the soft and hard tissues and, more importantly,
correlated each level of recession to an estimated percentage of root coverage (Table 1).8 In essence, the higher the level of interproximal bone, the better the result.
Arguably, maintenance of a robust blood supply
primarily determines graft survival.9 The adjacent and underlying bone provides the source, as do patent vessels in the surrounding
mucosa. Thus, a substantial volume of bone and
soft tissue become equally essential.
Thick gingiva holds more intact vascular structures to feed the
graft, whether the donor material is a repositioned flap or free
tissue. There is no definitive set minimum
measurement that denotes “thickness,” but
generally, a flap that exceeds 1 mm favors success.10
Ultimately, if revascularization fails to occur, the graft dies, so close
adaptation of the graft to the root and
neighboring bone is a requirement.
Along with significant bone loss and relatively
thin gingiva, the clinician must ensure
that potential recipient sites do not possess the following, as these
local factors hinder graft take: severe
caries; existing cervical restorations; ectopic enamel; calculus; and hyperactive muscle attachment.
Once the surgeon clears the above requirements,
he or she must screen for smoking,
which affects wound repair. Tobacco use
impairs oxygen exchange, collagen turnover, and immunologic response. To combat these problems, the patient
should abstain from smoking at least 1 week
before treatment and most likely refrain for the majority of the healing period, which is a
minimum of 1 month postsurgery.11,12
Before consideration of the types of
intervention, the clinician must first
ask the following questions: Is the etiology addressed? Is there no or minimal bone loss? Is there
thick tissue (at least 1 mm) at the recipient
site? Is the patient a nonsmoker? Only
when all answers are affirmative may root coverage surgery proceed.
ROOT COVERAGE GRAFTING
The final step is the selection of a suitable
grafting regimen. What treatments exist? Which
methods are best? There are two main types of
root coverage procedures: reconstructive flaps (known also as “pedicle grafts”) (Figure 2 View Figure) and free
grafts (Figure 3 View Figure).13 The first category
uses tissue adjacent to the receded area and
still attached at the base to cover the defect. This flapped mucosa may be rotated or simply advanced
coronally to obscure the recession. This may
or may not involve the papilla. Because
there is a limit to the amount of available adjoining tissue and of lateral slide achievable, the rotational flap treats
single receded
areas with relative ease but multiple sites with difficulty. A coronally advanced flap (CAF), conversely, uses the
gingiva immediately apical to the recession
and does not compromise tissue overlying
adjacent roots, permitting it to cover a more extensive
region of recession.14-16
Alternately, the clinician may prefer to isolate
tissue from a discrete secondary location.
Compared to reconstructive flaps—rotational
ones especially—free grafts usually provide more donor tissue but do not sustain a continuous blood supply. Free
grafts consist of autogenous or allogenic tissue. Harvested typically from
the host palate but occasionally other sites (eg, edentulous ridge, attached buccal gingiva), the
free gingival graft (FGG) possesses a full
layer of surface epithelium whereas the connective
tissue graft (CTG) does not.17,18 That said, some clinicians
leave a thin coronal strip of epithelium on the CTG to facilitate
suturing (Figure 4A View Figure and Figure 4B View Figure).
Processed allograft from human dermis also serves as
a free source. With cellular components removed
but vasculature, collagen network, ground
substance, and elastic fibers remaining, acellular
dermal matrix (ADM) bars the need for a second surgical site and, as it is
collected from cadavers, has a virtually limitless supply (Figure 5A View Figure, Figure 5B View Figure, Figure 5C View Figure and Figure 5D View Figure). With respect to defect elimination, case reports demonstrate high cosmetic success, but
again, very few controlled trials support its use, as a recent
meta-analysis suggested.19 In a retrospective analysis, Harris compared connective
tissue graft to ADM mean root coverage after 4 years and discovered that only CTG sites retained a high percent of
coverage at 97%.20 The average root coverage of teeth treated with ADM declined from 93% to 66% over the study period. Thus, acellular dermal matrix may lack endurance,
perhaps due to the presence of elastic fibers
that shrink.
Both reconstructive flaps and free grafts cover the
root surface mostly with a long junctional
epithelium or a scar; they do not restore the
lost attachment apparatus (ie, bone, connective tissue, and cementum). To ameliorate this, some
practitioners perform guided
tissue regeneration (GTR) in conjunction with coronally positioned
flaps. Membranes, either absorbable or nonabsorbable,
impede epithelial down-growth and thus help to
reestablish the connective tissue attachment via site repopulation with
cementoblasts, osteoblasts, and periodontal ligament fibroblasts.21 In theory, such an attachment creates long-term stability. An investigation on GTR-mediated root coverage found 10-year maintenance of recession-depth improvement,
though some attachment loss occurred over time.22 Harris, in contrast, saw significant and rather rapid
deterioration of early GTR results, from 92% mean coverage at 6 months
to just 60% at 2 years.23 No randomized
controlled trials exist to verify these
findings.
Bone graft may be used as an adjunct to membranes to
encourage
hard tissue regrowth over the recession defect, though studies fail to show any added benefit from demineralized freeze-dried bone allograft.24,25 Moreover, human histology presents
minimal or inconsistent evidence of new bone and cementum from guided tissue regeneration.26 Accordingly,
it is unfeasible to advocate use of
membrane technology over traditional techniques,
though it certainly remains a viable treatment option.
To be sure, there is a movement in periodontics
to embrace the application of potentially
regenerative materials to augment or even
substitute for conventional therapy. This marks a conceptual evolution of
the field from being anecdotally based to biologically
rooted—a good thing—but at present, no longitudinal proof
exists to substantiate claims of true regeneration or clinical
superiority. As encouraging evidence mounts, however, better recommendations may be offered. Currently, groups employ several major biomimetic or human-derived
products to improve root coverage, with mixed
or unexceptional results (Table 2).27-32 This is not
to say such materials do not work; there are
promising scientific rationales for their function, but they may require
improved clinical formulations.
It is obvious that myriad ways exist to cover root
recession. Which method gives the most
predictable result? Strong data suggests that
the CTG attains and sustains the greatest outcomes.
Considered the “gold standard” of recession treatment, the CTG provides the highest frequency of 100% root coverage
(Table 3).33 An example of a connective tissue graft is illustrated here (Figure 6A View Figure, Figure 6B View Figure and Figure 6C View Figure). In the end, the proper choice of therapy depends on defect morphology (Table 4).
No matter the treatment modality delivered,
surgical overcorrection of a defect is not
only desirable but also nearly mandatory. That is, the best way to
guarantee a long-lasting, esthetic result is
to attempt coverage beyond the borders of the recession. If the clinician employs a flap, he or she should make sure
it extends past the defect. For instance, a coronally advanced
flap ought to be positioned at least 2 mm coronal to the CEJ to ensure
complete root coverage.34 If a free graft is used, it should be wide, with some thickness (and firmly adapted to the underlying tissue). Such overcorrection minimizes the effect of
graft pullback and increases the likelihood of viability.
If therapy failed to cover the recession 100%
initially, it is still possible to
observe more root coverage over time, under the condition that grafting thickened the tissue. On occasion, a 1 mm coronal displacement of gingiva, dubbed “creeping
attachment,” transpires 1 year postsurgery, barring inflammation.35-37 Contingent
to a considerable degree upon thick tissue, the probability of creeping
attachment increases for narrow initial defects, isolated defects, a
lingual tooth position, good oral hygiene, and younger patients.38 Thicker
gingiva at the very least resists further recession if not favors actual
defect reduction.
CONCLUSION
If “I want a better smile” is the chief
complaint of a patient, the practitioner
must scrutinize not only the face, lips, and teeth, but also the periodontal drape. Treatment may include all the dental specialties as well as some medical ones to move and
reshape teeth, shift the jaws,
reconfigure facial structures, and position
gingiva. The conscientious dentist realizes that even subtle revision of the soft tissue frame over the teeth causes
visual tension and knows that gingival recession in particular ages people. Restoration of ideal mucosal contours via root
coverage is
crucial to the design of a pleasing smile. Keen diagnosis and elimination of receded areas may, at times, transform a
listless face into
a vibrant one and, consequently, bolster the patient’s self-worth, an incalculable reward.
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12. Bergstrom
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14. Allen EP, Miller PD Jr. Coronal
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19. Gapski R,
Parks CA, Wang HL. Acellular dermal matrix for mucogingival surgery: a
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20. Harris RJ.
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741-756.
34. Pini Prato GP, Baldi C, Nieri M, et al.
Coronally advanced flap: the post-surgical position of the gingival margin is an
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35. Harris RJ. Creeping attachment
associated with the connective tissue with partial-thickness double pedicle
graft. J Periodontol. 1997;68(9):890-899.
36. Dorfman HS, Kennedy JE, Bird WC.
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37. Matter J.
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38. Matter J, Cimasoni G. Creeping
attachment after free gingival grafts. 1976;47(10):574-579.
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Figure 2 Types of reconstructive flaps.
Figure 3 Types of free grafts.
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Figure 1 |
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Figure 4A Free gingival graft. Note the full epithelial coverage on
the graft. |
Figure 4B Connective tissue graft. A small band of epithelium, demarcated by its lighter color, remains on the graft. |
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Figure 5A Miller Class I recession defect from tooth No. 22 through tooth No. 27. |
Figure 5B Acellular dermal matrix hydrated in sterile saline. |
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Figure 5C Acellular dermal matrix secured over root surfaces with 5-0 gut suture. |
Figure 5D Healing 18-month postsurgery. There is complete root coverage from tooth No. 22 through tooth No. 27. |
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Figure 6A Miller Class I recession from tooth No. 11 through tooth No. 13, and thin gingiva over teeth Nos. 8 through 10. Treatment goals included root coverage as well as gingival thickening to prevent future recession. |
Figure 6B Connective tissue graft in place. Note a small band of epithelium left on the graft around the cervical areas of the teeth. |
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Figure 6C Three-month postoperative photograph. There is complete root coverage of teeth Nos. 11 through 13 and thicker gingiva over teeth Nos. 8 through 10. |
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Table 1 |
Table 2 |
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Table 3 |
Table 4 |