Departments
Implants
Jan 2008 —
Vol. 2,
Iss. 1
The Maxillary Central Incisor Implant: A Guide for Ideal Esthetic Implant Placement
Michael K. Sonick, DMD
Michael K. Sonick, DMD
The surgical success of dental implants has become
quite predictable.1 It is no longer enough to merely achieve osseointegration
in dental implant therapy. Patients require implants that are esthetic as
well as functional. The responsibility to deliver an ideal esthetic implant
restoration begins with the surgeon.
Replacing a hopeless tooth presents a number of options
for the clinician. Treatment options include a fixed, bonded partial
denture; a fixed, tooth-supported bridge; a removable partial denture; and
a dental implant. Fixed and removable partial dentures are wrought with
problems. Implant restorations are often chosen for the following reasons:
• They are non-removable and permanent.
• Adjacent teeth are preserved.
• The success rate is significantly higher than
for a fixed bridge.
• The strength of the restoration is increased.
• The case is segmented.
• Extraction site bone is preserved and
stabilized.
• The patient is able to floss.
• Cosmetics are enhanced.
• Future dental costs are decreased.2
Once a treatment plan is selected, the sequence of
treatment must be determined. Many options
exist, and there is no one correct
sequence in implant treatment planning. Questions must be answered before
performing any implant treatment, and they include, but are not limited to,
the following:3
1. When do you place the implant: immediately, 2-months
post-extraction, or 6-months post-extraction?
2. Is bone grafting needed?
3. What do you graft with: autograft, allograft, synthograft, or
xenograft?
4. When do you graft: at extraction,
2-months post-extraction, or at the time of implant placement?
5. Is it done as a single-stage or two-stage procedure?
6. How many months do you wait for osseointegration?
7. When do you perform second-stage surgery?
8. How long thereafter do you begin the restoration process?
9. Is a provisional restoration needed?
10. If a provisional is used, how long do you keep the patient in a
temporary?
The scope of this article cannot adequately answer all
of these questions. Rather, one case (eg, the
extraction and replacement of a single hopeless
central incisor with a dental implant) will demonstrate
the options that were chosen to achieve an esthetic restoration. The replacement of a single-tooth implant is one of the greatest challenges in restorative dentistry.4 The rationale
for these decisions will be explored.
CASE PRESENTATION
The patient presented with a failing endodontically
treated central incisor (Figure 1 View Figure). The
apicoectomy failed, and the tooth had an acute abscess and a fistula.
Radiographically, she presented with a mutilated, shortened root
(Figure 2 View Figure). She expressed high cosmetic demands
and refused to have her teeth prepared for a
3-unit bridge, or wear a removable partial denture as a permanent solution.
The treatment plan was as follows:
1. Extract, bone graft, and provisionalize.
2. Heal for 2 months.
3. Place dental implant.
4. Heal for 2 months.
5. Expose the implant and place a
temporary healing abutment.
6. Perform guided gingival growth (non-surgical gingival graft).
7. Place permanent abutment and provisionalize.
8. Modify the temporary to achieve soft tissue maturation.
9. Take final impressions.
10. Deliver the final restoration.
Extraction and Grafting
Step 1 required an atraumatic extraction of the central
incisor. The extraction site was degranulated. All soft issue was removed
to favor the in-growth of new bone. A freeze-dried mineralized or
demineralized bone graft was placed into the socket, and a bovine collagen
plug was placed and closed with resorbable sutures (Figure 3 View Figure). The purpose
of the graft is twofold: soft tissue in-growth is delayed and bone
regeneration is favored; and the site is plumped out, yielding a greater
volume of tissue in which to place the implant
in 2 months. The collagen membrane serves to
maintain the graft and acts as a "poor man’s membrane" to retard epithelial downgrowth. While this is
not the ideal form
of bone regeneration, it does yield an increased amount of bone, especially
in enclosed extraction site defects with intact labial plates, as seen in
this patient.5
Heal for 2 Months
Healing was rapid once the infection was removed
(Figure 4 View Figure). At 2
months post-extraction, soft tissue maturation was achieved, and an adequate volume of bone
existed for the placement of the implant
(Figure 5 View Figure). Note that the papillae adjacent to the
extraction site were present despite the absence of contact
points. This is a result of sufficient bone to
support the soft tissue. Delaying implant
treatment for 2 months also allowed for soft tissue maturation. Because an
immediate implant was not performed, primary closure at the time of
extraction was not necessary. Therefore, a free gingival graft was not
necessary, and there was no distortion of the gingival architecture in an
attempt to achieve primary closure.
Dental Implant Placement: Incision Design and
Implant Alignment
The radiograph taken at 2 months post-extraction
(Figure 6 View Figure) revealed adequate bone in a
mesial-distal and occlusal-apical direction.
Bony fill was intimated in the space previously occupied by the tooth root. Given the excellent healing response of the
patient, it was decided to proceed with dental implant placement.
The incision design enabled visualization of the
buccal plate, without causing gingival recession over the adjacent teeth or
papillary loss. A vertical incision was made over the interradicular bone,
one tooth distal to the implant site (Figure 7A and Figure 7B). A
sharp incision was made perpendicular to the bone, extending from the
alveolar mucosa to the height of gingiva of the
adjacent tooth. A secondary incision began at a right angle to the vertical
incision and continued into the sulcus of the tooth
adjacent to the implant site. The incision was carried interproximally
into the sulcus to the palatal line angle of the tooth. At the palatal line
angle, the incision made a 90º turn to connect
horizontally with the palatal line angle of the other tooth adjacent to the implant site (Figure 8). The incision was
carried intrasulcularly through the interproximal and buccal sulcus. If necessary, a second vertical incision could have
been made in the same place on the contralateral side. This would only be
necessary when extensive bone grafting, visualization, and reflection are
required.
After completion of the incision to bone, a
full-thickness flap was reflected buccally.
Full-thickness flap reflection was necessary to visualize bony anatomy.
Without flap reflection, fenestrations and
dehiscences go undiagnosed, leading to less bone-to-implant contact.
The opportunity to graft these areas at implant surgery is lost if a flap
is not elevated. It is the author’s opinion that flapless surgery is
difficult and rarely indicated because it "handcuffs" the
surgeon and frequently results in less than optimal regenerative treatment.
Implant placement requires a 3-dimensional mindset:
mesial-distal, buccal-palatal, and occlusal-apical.6,7
Mesial-Distal
The gingival zenith (ie, most apical point of gingival
tissue) of the maxillary central incisors is located distal to the long
axis of the tooth.8 Therefore, placement of the maxillary central incisor is slightly distal to the midline of the tooth. Also, the nasal
palatine foramina frequently dictates distal
placement to avoid hitting the nerve. The
clinician should attempt to keep the implant 1.5 mm to 2 mm from adjacent teeth (Figure 7A View Figure ; Figure 7B View Figure ; Figure 8 View Figure) so that bone may be preserved, leading to retention of the papillae.7,9
Buccal-Palatal
Ideal implant placement is slightly palatal to the
palatal-incisal line angle (Figure 8 View Figure). This creates a proper buccal
emergence profile. If the implant is angled
palatal to this line, a ridge lap restoration
may be necessary. Conversely, angling the implant too labially will result in a loss of labial gingival height and an
uneven gingival margin.
Occlusal-Apical
Ideal position is 3 mm to 4 mm from the
"anticipated" dento-gingival junction (Figure 7A View Figure and
Figure 7B View Figure).10 This provides room to develop a proper emergence profile, or running room. Deeply placed implants are difficult to clean and may trap debris or
excess cement. Shallow implants are at risk
of exposure and may not allow adequate space for a properly formed
restoration.
Second-Stage Surgery
The implant was allowed to heal for 2 months before
exposure. Second-stage surgery presents the
surgeon with an opportunity to increase tissue thickness, increase keratinized gingiva and
provide proper ridge contour. The incision connected the
interproximal-palatal line angles of the adjacent teeth and extended
interproximally (Figure 9A View Figure ; Figure 9B View Figure ;Figure 10 View Figure). This allowed the flap to be raised buccally, creating additional gingival
tissue without the need for a gingival graft. A
titanium temporary healing abutment was placed, and the gingiva was pulled
coronal to the abutment and secured with two resorbable (gut) sutures
(Figure 11 View Figure).
Guided Gingival Growth
Titanium is "gingiva loving." Gingiva will
grow to completely cover a titanium
temporary healing abutment if placed slightly coronally
(Figure 12). This technique is used when gingival tissue is desired (Figure 11 View Figure and Figure 12 View Figure). The author has called this
a "non-surgical gingival graft"
because the body creates additional gingiva
without the need for performing gingival surgery. A certain amount of recession is anticipated the first year after the
implant restoration.11 Therefore, it is
recommended to over-build up the gingival tissue
by 25%.12
It is always easier to subtract than to add.
Permanent Abutment Placement and
Provisionalization
Four weeks after uncovering the implant and
"non-surgical gingival grafting," an implant level impression
was taken, and a gold GingiHue™ Post (Implant Innovations Inc, Palm Beach Gardens, FL) was
fabricated (Figure 13 View Figure). A provisional restoration was made and cemented
with temporary cement (Figure 14 View Figure).
Modification of the Temporary to Achieve Soft
Tissue Maturation
All implants in the esthetic zone are provisionalized,
which enables the clinician to refine the esthetics before fabricating the
final restoration. The patient also has the opportunity to approve the
restoration at this time. Acrylic can be added or subtracted in an attempt
to guide the formation of the papillae and develop the proper emergence
profile. A papilla will form if the contact point of the provisional is
within 4 mm to 5 mm of the alveolar bone (Figure 15 View Figure).7,13 It is not uncommon to
keep the patient in the provisional for 3 months before the final
impression is made.
Delivery of the Final Restoration
The final restoration was a recapitulation of the
provisional restoration. A comparison of the final restoration to the
initial tooth revealed little difference in shape and soft tissue
architecture (Figure 1 View Figure, Figure 16 View Figure, and Figure 17 View Figure). One month after the
placement of the final restoration, excess labial gingiva was seen on the
implant restoration when compared to the contralateral natural central
incisor (Figure 16 View Figure and Figure 17 View Figure). At 1 year, if the patient is not satisfied with the excess gingival tissue, it
can be easily removed to achieve symmetry.
CONCLUSION
This case serves as a guide by which to perform an
ideal esthetic maxillary central incisor implant restoration. The concepts
provided are proven and supported by both clinical experience and
evidence-based literature. However, there are many treatment alternatives
available today that would have achieved a similarly satisfactory esthetic
result, and there are advantages and disadvantages to each. Each treatment
scenario presents unique challenges and opportunities for clinicians to
serve our patients with ideal esthetic, functional, and long-lasting
implant dentistry. It is up to the individual clinician to explore the
various treatment options and decide which works most predictably and
easily so that patients will be better served.
REFERENCES
1. Adell R, Eriksson B, Lekholm U, et al. Long-term
follow-up study of osseointegrated
implants in the treatment of totally edentulous jaws. Int J Oral Maxillofac
Implants. 1990;5(4):347-359.
2. Priest G. The economics of implants for
single missing teeth. Dental Economics. 2004;94(5):130-8.
3. Sonick M. Bone
sculpting to achieve papilla regeneration around dental implants. Contemporary
Esthetics and Restorative Practice. 2002;6(6):46-53.
4. Jansen CE, Weisgold A. Presurgical
treatment planning for the anterior single-tooth implant restoration. Compend
Contin Educ Dent. 1995;16(8):746-761.
5. Fugazzotto P. Treatment options following
single-rooted tooth removal: a literature review and proposed
hierarchy of treatment selection. J Periodontal. 2005;76(5):821-831.
6. Sonick M. Hard and soft tissue
regeneration for implants in the esthetic zone. Contemporary Esthetics
and Restorative Practice. 2001;5(10):64-76.
7. Grunder U, Gracis S, Capelli M. Influence
of the 3-D bone-to-implant relationship on esthetics. Int J Peridontics
Restorative Dent. 2005;25(2):113-119.
8. Rufenacht CR. Fundamentals of Esthetics. Chicago:
Quintessence Pub Co. 1990;127.
9. Esposito M,
Ekestubbe A, Grondahl K. Radiographic evaluation of marginal bone loss at tooth surfaces facing single
Branemark implants. Clin Oral Implants Res. 1993; 4(3):151-157.
10. Parel S, Sullivan D. Esthetics and
Osseointegration. Osseointegration Seminars, Inc. Dallas: Taylor
Publishing Company; 1989.
11. Small PN, Tarnow DP. Gingival recession
around implants: a 1-year longitudinal prospective study. Int J Oral
Maxilofac Implants. 2000;15(4):527-532.
12. Jovanovic SA, Paul S, Nishimura R.
Anterior implant-supported reconstructions: a surgical challenge. Pract
Periodontics Aesthet Dent. 1999;11(5):551-558.
13. Tarnow DP, Cho SC, Wallace SS. The effect
of inter-implant distance on the height of inter-implant bone crest. J
Periodontal. 2000;71(4):546-549.
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Figure 1 Initial presentation. Tooth No. 9, the left maxillary central
incisor, has a fistula from a failing apicoectomy. Note the discolored
gingival tissues. |
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Figure 2 Radiograph of the failed apicoectomy. Truncated root
and apical radiolucency are evident. The prognosis is hopeless. |
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Figure 3 The tooth was extracted atraumatically. Following degranulation, freeze-dried demineralized bone allograft was placed with a bovine collagen plug. The collagen helped contain the graft and served as a barrier membrane, as well as a hemostatic agent. |
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Figure 4 Two weeks post-extraction. Excellent healing and formation of anatomy to support the future implant is evident. |
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Figure 5 Healing 2 months after extraction. Note retention of papilla. Labial gingival contour has been preserved. |
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Figure 6 Radiograph at 2 months after extraction, the day of implant surgery. Bony healing appears to be proceeding nicely. |
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Figure 7A Labial view of the flap design and implant placement. Vertical incision was made one tooth distally on the interradicular bone at a right angle to the bone. The vertical incision connected horizontally at a right angle at the level of the gingival sulcus. Note the 3-dimensional position of the implant. It is slightly distal and 3 mm from the anticipated dento-gingival junction. |
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Figure 7B The incision design began one tooth mesial and distal to the implant site with a vertical incision that extended from the alveolar mucosa to the height of gingival contour. It extended intrasulcularly to the palatal line angles of both teeth and connected horizontally across the palate. Note the implant position is 3 mm from the anticipated dento-gingival junction and 2 mm from the adjacent teeth. |
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Figure 8 Occlusal view of implant placement. The implant is slightly palatal to the palatal incisal line angle so that proper emergence profile is achieved. Note the palatal incision to preserve labial tissue. The labial plate of bone has also been preserved by a judicious extraction and grafting procedure. |
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Figure 9A Implant exposure and second-stage surgery. The initial incision was made from palatal line angle to palatal line angle of the adjacent teeth. Note the volume of gingival tissue that is displaced labially, allowing for additional gingival augmentation. Note the amount of bone covering the dental implant. |
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Figure 9B Incision for second-stage surgery was palatal connecting the palatal line angles of the teeth adjacent to the implant site. It then extended intrasulcularly to the buccal line angles of the teeth. The flap was then reflected labially and created a volume of tissue to be moved labially, which added additional bulk to the labial profile of the implant. |
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Figure 10 Occlusal view of the implant at second-stage surgery after removal of the cover screw and bone profiling. |
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Figure 11 Suturing with gut during second-stage surgery after placement
of the titanium temporary healing abutment. Gingiva is placed
labially and coronally elevated over the temporary healing abutment to
achieve even more gingival growth (eg, a non-surgical gingival graft). |
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Figure 12 Two weeks post-exposure, the temporary healing abutment
is almost completely covered by the gingiva. Additional gingival
augmentation has been achieved labially and coronally. |
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Figure 13 A permanent abutment has been fabricated. Note the
labial gingival profile. Augmentation makes it appear as if there is a
root prominence. |
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Figure 14 Immediate acrylic provisionalization of the permanent
abutment. Papillae have not yet formed between teeth Nos. 8 and
9, and teeth Nos. 9 and 10. |
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Figure 15 The provisional restoration has been in place for 3 weeks.
Note that the papillae are almost completely formed. The patient is
almost ready for the final impression. |
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Figure 16 Final implant restoration of tooth No. 9, the maxillary left
central incisor. Compare to Figure 1. Note gingival harmony, papillae
reformation, absence of the fistula, and improvement of the
color of the gingiva. |
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Figure 17 Final implant restoration of tooth No. 9. (Restoration courtesy
of Dr. Ira Novsam, Westport, CT.) |
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