Managing Congenitally Missing Lateral Incisors.

Part III: Single-Tooth Implants

GREGGORY A. KINZER, DDS, MSD*
VINCENT O. KOKICH JR, DMD, MSD†

ABSTRACT
Three treatment options exist for the replacement of congenitally missing lateral incisors. They
include canine substitution, a tooth-supported restoration, and a single-tooth implant. Selecting
the appropriate treatment option depends on the malocclusion, anterior relationship, specific
space requirements, and condition of the adjacent teeth. The ideal treatment is the most conserv-
ative option that satisfies individual esthetic and functional requirements.

Today, the single-tooth implant has become one of the most common treatment alternatives for
the replacement of missing teeth. This article closely examines the many interdisciplinary issues
that arise when treatment planning the placement of single-tooth implants in patients with con-
genitally missing lateral incisors. The specific criteria that must be evaluated illustrate the impor-
tance of an interdisciplinary treatment approach to achieve optimal esthetics and long-term
predictability. This is the final article of a three-part series discussing the three treatment alterna-
tives for replacing congenitally missing lateral incisors.

CLINICAL SIGNIFICANCE
When treatment planning single-tooth implants to replace congenitally missing lateral incisors,
an interdisciplinary approach is necessary to provide the most predictable treatment outcome.

(J Esthet Restor Dent 17:202–210, 2005)

T he replacement of congenitally
missing lateral incisors raises
several important treatment plan-
involves little tooth preparation
other than some minor coronal
reshaping to improve the esthetics
gories: a single-tooth implant or a
tooth-supported restoration. Part
II of this series discussed the three
ning concerns. Therefore, no matter and function of the maxillary primary types of tooth-supported
what treatment option is chosen, canines as lateral incisors. How- restorations: a resin-bonded fixed
it is beneficial to use an interdisci- ever, there are many individuals partial denture, a cantilevered
plinary treatment approach to get who do not meet the qualifications fixed partial denture, or a conven-
the most predictable outcome. necessary to be considered for tional full-coverage fixed partial
One of the primary considerations canine substitution. In these denture. Although each of these
among all treatment options is patients, some form of restoration restorative treatment options can
conservation of tooth structure. In must be considered. be used to achieve predictable
Part I of this series, the treatment esthetics, function, and longevity,
alternative discussed was canine The restorative treatment alterna- they require varying amounts of
substitution. This typically tives can be divided into two cate- tooth structure removal.

*Affiliate assistant professor, Department of Prosthodontics, University of Washington, Seattle, WA, USA
†Affiliate assistant professor, Department of Orthodontics, University of Washington, Seattle, WA, USA

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 KINZER AND KOKICH

Today, the single-tooth implant has evaluating periapical or panoramic either prior to or in conjunction
become one of the most common radiographs, the orthodontist can with implant placement to achieve
treatment alternatives for the evaluate the position of the optimal alveolar ridge thickness.
replacement of missing teeth.1–6 unerupted maxillary canine (Fig-
Various studies have shown the ure 1). If the crown of the perma- Space Appropriation
successful osseointegration and long- nent canine is apical to the primary As was discussed in the second part
term function of restorations sup- canine root, it may be necessary to of this series, there are four meth-
ported by single-tooth implants.7–10 selectively extract the primary lat- ods of determining the appropriate
In addition to the high success rates eral incisor to encourage the perma- spacing for patients with missing
of implant-supported single-tooth nent canine to erupt adjacent to the maxillary lateral incisors. The first
replacement, one of the main advan- central incisor (Figure 2).11 is the golden proportion. This
tages of this type of restoration is method measures teeth by evaluat-
the ability to leave the adjacent If an implant restoration is to ing a smiling or frontal intraoral
teeth untouched. This is particu- replace the missing lateral incisor, photograph in a two-dimensional
larly beneficial when dealing with the thickness of the alveolus must view. Since the maxillary teeth are
young patients and unrestored den- be adequate to allow proper positioned along an arc, each tooth
titions. However, implants cannot implant placement. Without the should be 61.8% wider than the
be placed until facial growth is eruption of the permanent lateral tooth distal to it.15
complete. Therefore, monitoring incisor, the osseous ridge in this
eruption in these patients at an area does not fully develop. If the
early age is important for optimal permanent canine is allowed to
implant site development. erupt mesially through the alveolus
into the lateral position, its large
This final segment of the series buccolingual width will influence
describes the interdisciplinary inter- the thickness of the edentulous
action between the orthodontist ridge. When the permanent canine
and the restorative dentist as they is orthodontically moved distally,
diagnose and treat patients requir- an increased buccolingual alveolar
ing single-tooth implants to replace width is established (Figure 3).12
congenitally missing maxillary Studies have shown that if the
lateral incisors. implant site is developed by this
orthodontic tooth movement, its
IMPLANT SITE DEVELOPMENT buccolingual width remains stable
The first person to diagnose a con- over time.13,14 This is especially
genitally missing maxillary lateral beneficial given that an implant
incisor is often the restorative den- cannot be placed until facial growth
tist. It may be discovered in patients is complete. If the canine does not
between 7 and 10 years of age, at erupt near the central incisor or
Figure 1. The goal is often selective
which time a referral may be made cannot be guided into this position, extraction of the retained primary lateral
to see the orthodontist. Frequently, the osseous ridge will not fully to encourage eruption of the permanent
canine into the missing lateral incisor
these children have retained maxil- develop. In these cases, it may be position. This ultimately develops the
lary primary lateral incisors. By necessary to place a bone graft alveolar ridge for implant placement.

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 MANAGING CONGENITALLY MISSING LATERAL INCISORS: SINGLE-TOOTH IMPLANTS

Figure 2. As the permanent canine erupts adjacent to the Figure 3. The canine is moved distally, leaving behind an
central incisor, its large buccolingual width begins to develop adequate buccolingual width for implant placement.
the alveolar ridge in the edentulous area.

The second method is to use the space should be ideal for a lateral On the other hand, if the edentu-
contralateral lateral incisor if it has incisor restoration.16,19,20 Generally lous space for the lateral incisor is
a normal width.16 However, this this width ranges from 5 to 7 mm. only 5 mm wide and a traditional
method is not appropriate if the 3.75 mm diameter implant is used,
contralateral tooth is missing or It is important to evaluate the there will be less than 0.5 mm of
peg shaped. width of the edentulous space that space between head of implant and
is created for the lateral incisor the adjacent teeth. The result would
The third method of space appro- when determining the appropriate be inadequate space for the inter-
priation is to conduct a Bolton size of the implant to placed. To dental soft tissue and, hence, a
analysis.17 This is a quick and reli- have adequate room for the devel- compromised papillary position. In
able way to determine the proper opment of the papillae, 1.5 to this situation, a smaller-diameter
spacing for missing or malformed 2.0 mm of space is recommended implant should be used.
teeth. Bolton introduced this between the head of the implant
method in 1958 as a way to com- and the adjacent teeth.21 Given the After the appropriate amount of
pare the mesiodistal widths of the range of widths for the lateral coronal space has been determined,
dental arches to achieve ideal incisor space and the current it is necessary to evaluate the inter-
occlusal relationships.18 Use of this implant dimensions, this may not radicular spacing.16 The restorative
method is described in detail in always be feasible. If the edentulous treatment that is chosen to replace
Part II of the series (J Esthet Restor space for the lateral incisor is 7 mm the missing lateral incisor is often
Dent 2005;2:76–84). wide, a traditional implant diame- based on whether adequate spacing
ter of 3.75 mm can be used. This can be established between the root
The most predictable method is to implant, which has a 4.1 mm plat- apices. To place an implant, the
construct a diagnostic wax-up. If form, leaves about 1.5 mm of space minimum interradicular distance is
the anterior and posterior teeth are between the implant and the adja- generally 5 mm. This amount of
set in their ideal functional and cent teeth for the development and interradicular space provides enough
esthetic relationships, the remaining maintenance of the papilla. room for placement of a small-

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 KINZER AND KOKICH

diameter implant with approxi-

mately 0.75 mm of bone between
the implant and the adjacent roots.

Problems with inadequate space

between the root apices are gener-
ally due to improper mesiodistal
root angulation. This is noticeable
when time is not taken to align the
roots properly. When the orthodon-
tist opens space for the missing lat-
A B
eral incisor, the crowns of the
maxillary central incisor and canine Figure 4. A, After the canine erupts adjacent to the central incisor, the appropriate
are tipped apart. Unfortunately, the amount of coronal space must be opened for the missing lateral incisor. B, When
the space is opened, the crowns of the central incisor and canine are tipped apart.
roots of these teeth do not move as
quickly (Figure 4). This problem of
root proximity often goes unno-
ticed and, as a result, uncorrected, be tipped labially during orthodon- keratinizes, but the location of the
making it impossible for the sur- tic treatment because of the under- papilla does not change (Figure 9).
geon to place an implant. There- lying Class III skeletal tendency. This can pose an esthetic challenge
fore, it is important to take a The maxillary facial cortical plate
periapical radiograph of the edentu- limits any significant labial root
lous area prior to removing ortho- movement of the maxillary incisors.
dontic appliances to confirm the Therefore, it may be impossible to
ideal root position and adequate achieve the interradicular spacing
spacing for a future implant place- necessary for implant placement in
ment (Figure 5).13,16 these patients. In this situation, an
alternate restorative option is
In certain patients it may be impos- required (Figure 8).
sible to achieve acceptable inter-
radicular spacing using orthodontics, Papillary Changes during
even though the coronal spacing Space Appropriation
may be ideal. An example would be In adult patients, the direction of
a patient with a Class III tendency tooth movement affects papilla
malocclusion requiring proclination heights on the distal aspect of the
of the maxillary incisors (Figure 6). central incisors and the mesial
As the maxillary incisor crowns are aspect of the canines. According to
aligned, they are tipped labially. Atherton, as teeth are moved away
However, their roots do not move from each other during space open-
coincidentally. They tend to con- ing, the papilla remains stationary Figure 5. To confirm the clinical evalu-
verge toward each other resulting in as the adjacent sulci are everted.22 ation, a periapical radiograph is taken
during orthodontic treatment to evalu-
a “wagon-wheel” effect (Figure 7). The exposed nonkeratinized gingiva ate the relationship between the roots
Unfortunately, these roots cannot appears red. Over time this tissue of the central incisor and the canine.

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 MANAGING CONGENITALLY MISSING LATERAL INCISORS: SINGLE-TOOTH IMPLANTS

occlusal, and restorative problems

may be created.11

So, how do we determine the com-

pletion of growth for individual
patients? Hand-wrist radiographs
are occasionally taken to assess
growth. However, they do not pre-
A
dictably determine the cessation of
Figure 6. A, This patient had previously been facial growth. The most predictable
restored with resin-bonded fixed partial dentures way to monitor facial growth is by
that subsequently failed. B, Inadequate interradic-
ular spacing for implant placement necessitated evaluating serial cephalometric radi-
the need for orthodontic treatment. B ographs taken 6 months to 1 year
apart.12 These radiographs, when
superimposed, illustrate any changes
in vertical facial height over the spe-
for the periodontist and restorative TIMING OF IMPLANT PLACEMENT cific time period. If the two sequen-
dentist when placing the implant What is the appropriate time to tial radiographs show no growth,
and designing the restoration. For- place an implant? The answer to then an implant can be placed and
tunately, this does not tend to occur this question is based on a patient’s significant eruption of the adjacent
in adolescent patients owing to the facial growth. As the face grows teeth will not be expected.13
fact that as a child’s face continues and the mandibular rami lengthen,
to grow and the teeth erupt, the teeth must erupt to remain in occlu- INTERIM TOOTH REPLACEMENT
AFTER ORTHODONTICS
bone and gingiva constantly sion. Implants cannot erupt. If an
change. As a result, the papillae implant is placed before a patient If implants cannot be placed until
adjacent to the implant site are not has completed his or her facial facial growth is complete, how is
affected permanently. growth, significant periodontal, the edentulous space maintained

A B

Figure 7. A, When the maxillary anterior teeth are at the proper inclination, there should be adequate interradicular space for
implant placement. B, When the maxillary incisors are proclined, the root apices converge. This often creates root proximity
problems that make implant placement difficult.

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 KINZER AND KOKICH

A B

Figure 8. A, Because adequate room could not be opened apically, a cantilever fixed partial denture was chosen to replace the
lateral incisors and alter the esthetics of the canines. B, The final restoration of the cantilevered fixed partial dentures replacing
the lateral incisors. Connective tissue grafting was done to improve the pontic–soft tissue relationship.

from the time the orthodontic appli- One option is to use a removable replace the missing tooth as well as
ances are removed until the implant retainer with a prosthetic tooth. ensure postorthodontic retention.
is able to be placed and restored? This is an easy and efficient way to Care must be taken to ensure that

A B

Figure 9. A, In this adult patient, the canine was moved

mesially, thus everting the sulcus distal to the canine. B and
C, This red, nonkeratinized, sulcular epithelium gradually
keratinizes over time. However, the position of the papilla does
not change.

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the retainer is supported by the to dictate the placement of the abutment. Typically the diameter of
adjacent teeth rather than solely implant.23 The other benefit of the the healing abutment is narrower
resting on the soft tissue in the eden- surgical guide is that it can easily be than the diameter of the tooth to be
tulous area. This helps avoid exces- used to index the position of the replaced (Figure 10). As a result,
sive pressure and inflammation of implant for use in the fabrication of the tissue does not have the same
the ridge and papillary areas. an implant-supported provisional scalloped architecture that is pre-
restoration. After implant place- sent around natural teeth.
The use of a retainer works well ment, 4 to 6 months should be
when a short period of time is allowed for adequate osseointegra- When a provisional restoration is
anticipated until the implant can be tion to occur. placed, the subgingival contours and
placed. If it will be years before shape of the provisional will influ-
growth is completed and an Prosthetically Guided Soft Tissue ence the position of the soft tissue
implant can be placed, a more long- Management (Figure 11).25,26 Adding more con-
term provisional is recommended. Once the implant has been surgi- tour to the facial aspect of the pro-
With long-term use, a removable cally uncovered, the restorative visional causes the facial free
retainer can cause problems of tis- phase begins. Rather than proceed- gingival margin to move apically,
sue inflammation and papillary ing directly to the final impression whereas adding interproximal con-
hyperplasia. As discussed in Part II and fabrication of the definitive tour to the provisional helps create
of the series, a more appropriate crown, a provisional restoration a more ideal papillary form (Fig-
long-term provisional is a resin- should be placed on the implant. ure 12). The provisional restoration
bonded fixed partial denture. This The main purpose of placing a pro- is generally allowed to remain in
type of restoration keeps excessive visional restoration is to prostheti- place for 4 to 6 weeks. After this
pressure off the ridge and can help cally guide the soft tissue into its amount of time, the position of the
support the papilla. In addition, it final position.24 After the implant is tissue, as guided by the contours of
can be removed when it is no surgically uncovered, the soft tissue the provisional, should be stable
longer needed with minimal alter- is allowed to heal around a healing (Figure 13). A final impression of
ation of the adjacent teeth.

IMPLANT PLACEMENT

To ensure proper implant place-

ment, a surgical guide should be
fabricated from a diagnostic wax-
up. The purpose of the guide is to
provide information regarding
tooth position to the surgeon to
help guide implant placement. The
two most important elements that
need to be incorporated into the
surgical guide are the incisal edge
position and the anticipated free
gingival margin location of the
Figure 10. The tissue has healed around a 4 mm tall healing
tooth to be replaced. This allows abutment. Note the height of the tissue is at the same level as
the position of the final restoration the adjacent papillae.

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 KINZER AND KOKICH

A B

Figure 11. A, Wax was used to create the three basic tooth morphologies that are seen in natural teeth (square, triangular, and
ovoid). B, Soft tissue replication material poured around the different tooth shapes illustrates the influence of tooth contour on
the resulting position of the soft tissue. A square cervical tooth shape results in a more square gingival architecture, whereas a
triangular cervical tooth shape leads to a more triangular gingival architecture. The amount of facial contour also influences
the position of the facial free gingival margin.

the implant can then be made that on the type of final restoration that of restoration is that it leaves the
transfers this information to the lab- is chosen, interdisciplinary manage- adjacent teeth intact. To provide
oratory for fabrication of the defini- ment of these patients often plays a adequate room both in the coronal
tive restoration (Figure 14). vital role in the facilitation of treat- and apical areas, orthodontics is
ment. One of the most common often necessary. This article dis-
SUMMARY treatment alternatives for the cusses the key points that need to
Many restorative options exist for replacement of congenitally miss- be addressed when replacing con-
the replacement of congenitally ing teeth is a single-tooth implant. genitally missing lateral incisors
missing lateral incisors. Depending The main advantage of this type with single-tooth implants.

Figure 12. This photograph was taken minutes after seating Figure 13. The provisional implant restoration seen in
the screw-retained provisional implant. The tissue blanching Figure 12 at a 6-week evaluation. Note how the contour of
that is present is transient and is due to the pressure caused the provisional has influenced the form of the tissue, causing
by the difference in the provisional’s subgingival contour controlled recession on the facial aspect while maintaining
compared with that of the healing abutment. the height of the papilla.

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16. Spear F, Mathews D, Kokich VG. Inter-

disciplinary management of single-tooth
implants. Semin Orthod 1997; 3:45–72.

17. Freeman JE, Maskeroni AJ, Lorton L. Fre-

quency of Bolton tooth-size discrepancies
among orthodontic patients. Am J Orthod
Dentofacial Orthop 1996; 110:24–27.

18. Bolton WA. Disharmony in tooth size and

its relation to the analysis and treatment
of malocclusion. Angle Orthod 1958;
28:113–130.
A 19. McNeill RW, Joondeph DR. Congenitally
absent maxillary lateral incisors: treatment
Figure 14. The final restoration (A) and radi- planning considerations. Angle Orthod
1973; 43:24–29.
ograph (B) of the single-tooth implant replacing
the congenitally missing lateral incisor at 1-year B 20. Nordquist GG, McNeil RW. Orthodontic
postinsertion. vs. restorative treatment of the congenitally
absent lateral incisor—long term periodon-
tal and occlusal evaluation. J Periodontol
1975; 46:139–143.
REFERENCES 9. Romeo E, Chiapasco M, Ghisolfi M,
Vogel G. Long-term clinical effectiveness 21. Saadun AP, LeGall M, Touati B. Current
1. Covani U, Crespi R, Cornelini R, Barone
of oral implants in the treatment of partial trends in implantology: part II—treatment
A. Immediate implants supporting single
edentulism. Seven-year life table analysis planning and tissue regeneration. Pract
crown restoration: a 4-year prospective
of a prospective study with ITI dental Periodontics Aesthet Dent 2004;
study. Periodontology 2004; 75:982–988.
implants system used for single-tooth 16:707–714.
2. Sadan A, Blatz MB, Salinas TJ, Block MS. restorations. Clin Oral Implants Res 2002;
13(2):133–143. 22. Atherton JD. The gingival response to
Single-implant restorations: a contempo-
orthodontic tooth movement. Am J Orthod
rary approach for achieving a predictable
10. Noack N, Willer J, Hoffmann J. Long- Dentofacial Orthop 1970; 58:179–186.
outcome. Int J Oral Maxillofac Surg 2004;
62(9 Suppl 2):73–81. term results after placement of dental
implants: longitudinal study of 1,964 23. Garber DA. The esthetic implant: letting
implants over 16 years. Int J Oral Maxillo- restoration be the guide. J Am Dent Assoc
3. Vermylen K, Collaert B, Linden U, Bjorn
fac Implants 1999; 14:748–755. 1995; 126:319–325.
AL, De Bruyn H. Patient satisfaction and
quality of single-tooth restorations. Clin 24. Touati B, Guez G, Saadoun A. Aesthetic
Oral Implants Res 2003; 14(1):119–124. 11. Biggerstaff RH. The orthodontic manage-
ment of congenitally absent maxillary lat- soft tissue integration and optimized emer-
eral incisors and second premolars: a case gence profile: provisionalization and cus-
4. Garber DA, Salama MA, Salama H.
report. Am J Orthod Dentofacial Orthop tomized impression coping. Pract
Immediate total tooth replacement. Com-
1992; 102:537–545. Periodontics Aesthet Dent 1999;
pend Contin Educ Dent 2001; 22:210–216,
11:305–314.
218.
12. Kokich VG. Managing orthodontic-
restorative treatment for the adolescent 25. Yamamoto M, Miyoshi Y, Kataoka S.
5. Mayer TM, Hawley CE, Gunsolley JC,
patient. In: McNamara JA, Brudon WL, Special discussion—fundamentals of
Feldman S. The single-tooth implant: a
eds. Orthodontics and dentofacial ortho- esthetics: contouring techniques for metal
viable alternative for single-tooth replace-
pedics. Ann Arbor, MI: Needham Press, ceramic restorations. Quintessence Dent
ment. J Periodontol 2002; 73:687–693.
2001:423–452. Technol 1990/1991; 14:10–81.
6. Naert I, Koutsikakis G, Duyck J, Quirynen
13. Kokich VG. Maxillary lateral incisor 26. Williams JL. The temperamental selection
M, Jacobs R, van Steenberghe D. Biologic
implants: planning with the aid of ortho- of artificial teeth, a fallacy. Dent Dig
outcome of single-implant restorations as
dontics. Int J Oral Maxillofac Surg 2004; 1914; 20:243–259.
tooth replacements: a long-term follow-up
study. Clin Implant Dent Relat Res 2000; 62:48–56.
2:209–218.
14. Ostler MS, Kokich VG. Alveolar ridge Reprint requests: Greggory A. Kinzer, DDS,
7. Weng D, Jacobson Z, Tarnow D, et al. A changes in patients congenitally missing MSD, 600 Broadway, Suite 490, Seattle,
mandibular second premolars. J Prosthet WA, USA 98122; e-mail:
prospective multicenter clinical trial of 3i
Dent 1994; 71:144–149. gkinzer@seanet.com
machined-surface implants: results after
6 years of follow-up. Int J Oral Maxillofac ©2005 BC Decker Inc
Implants 2003; 18:417–423. 15. Lombard RE. The principles of visual per-
ception and their clinical application to
8. Davarpanah M, Martinez H, Etienne D, denture esthetics. J Prosthet Dent 1973;
et al. A prospective multicenter evalua- 29:358–382.
tion of 1,583 3i implants: 1 to 5-year
data. Int J Oral Maxillofac Implants
2002; 17:820–828.

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