Download Management of missing maxillary anterior teeth with emphasis on

ADVANCES IN ORTHODONTICS & DENTOFACIAL SURGERY
Management of missing maxillary anterior
teeth with emphasis on autotransplantation
Björn U. Zachrisson, DDS, MSD, PhD,a Arild Stenvik, DDS, PhD,b and Hans R. Haanæs, DDS, PhDc
Oslo, Norway
O
ver 40 years
ago, Slagsvold
and Bjercke1
developed a method of
transplanting teeth with
partly formed roots. After transplantation, root
growth continues, and
the teeth maintain their
capacity for functional
adaptation. Endodontic
treatment is usually not
necessary.
The 3 main indications for autotransplantation of developing premolars are unevenly
distributed multiple agenesis, agenesis of the mandibular second premolars in low-angle face types
with normal or weak facial profiles, and accidentally
lost or congenitally missing maxillary central and
lateral incisors. Most traumatic injuries with accidental loss of maxillary incisors occur in children
between 7 and 10 years of age. This makes autotransplantation of developing premolars an interesting
treatment alternative.
The optimal time for autotransplantation of premolars to the maxillary anterior region is when the root
development has reached two thirds to three fourths of
the final root length.1,2 The prognosis for complete
periodontal healing at this stage of root development is
better than 90%.2 Next to timing, the most important
factors are the skill and experience of the surgeon
From the University of Oslo, Oslo, Norway.
a
Professor II of orthodontics.
b
Vice dean; professor of orthodontics.
c
Dean; professor of oral surgery and oral medicine.
Reprint requests to: Dr Björn U. Zachrisson, Stortingsgaten 10, 0161 Oslo,
Norway; e-mail, [email protected].
Presented at the American Association of Orthodontists/American Association
of Oral and Maxillofacial Surgeons Symposium, February 6-8, 2004; Palm
Springs, Calif.
Submitted and accepted, June 2004.
Am J Orthod Dentofacial Orthop 2004;126:284-8
0889-5406/$30.00
Copyright © 2004 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2004.06.007
284
(autotransplantation is not a quick fix; damage to the
periodontal ligament must be avoided because it might
lead to ankylosis), the presence of adequate space on
the mesial and distal sides of the transplant, the avoidance of interference (jiggling contacts) between the
graft and the opposing teeth during the first 2 months,
and physiologic mobility during the fixation period.
Conventional sutures are generally preferred for fixation when the transplant is placed in a half-erupted
position (Fig 1).
One sign of a successful autotransplantation is that
root development continues. Figure 2 shows the usual
sequence of continued root growth 2 years after transplantation of a premolar to replace an accidentally lost
maxillary left central incisor. The part of the root that
was formed at the time of operation always shows pulp
obliteration, whereas the part formed afterwards often
has a normal pulp chamber. Although the transplanted
tooth sometimes does not respond to electric pulp
testing, endodontic treatment is generally not necessary. However, when the pulp obliteration is rapid
(which in traumatology is defined as almost complete
obliteration of the entire pulp chamber within a year),
preventive endodontics might be safer than expectation,
to avoid the risk for perforations later if periapical
problems develop.
Long-term survival and success rates
The long-term outcome of tooth transplantation,
including gingival and periodontal conditions, was
examined in a recent study from the University of
Oslo.3 Patients’ attitudes about treatment and outcome were also evaluated. The follow-up period for
33 transplanted premolars ranged from 17 to 41
years, with a mean of 26.4 years. Both the survival
(teeth still present at the examination) and success
(teeth fulfilling defined success criteria) rates were
high—90% and 79%, respectively. The patients generally responded favorably regarding their perception of the treatment. The study showed that autotransplantation of teeth with partly formed roots
compares favorably in a long-term perspective with
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 126, Number 3
Zachrisson, Stenvik, and Haanæs 285
Fig 1. Developing mandibular left first premolar autotransplanted to replace accidentally lost left central
incisor in 9-year-old boy. A, Position of transplant after
operation was secured with sutures, and adequate
mesiodistal space had been created by the push-coil.
B, Composite resin buildup on premolar crown was
later replaced with PLV (photos courtesy of Dr S.
Toreskog). Note width of PLV along gingival margin.
Fig 2. Typical radiographic appearance over 2-year
period after autotransplantation of developing premolar
replacing accidentally lost left central incisor. A, After
accident, at transplantation, and 3 months later. B, Six,
12, and 24 months after accident. Note that root development continues after operation. Part of pulp formed
at operation has been obliterated, but not in part of root
that was formed afterward.
other treatment modalities for substituting missing
teeth.
incoming light will not be stopped by a bonded PLV,
and any later root exposure will display normal color
and no darkening of the gingiva.
In a recent study,4 45 premolars autotransplanted
to the maxillary incisor region in 40 adolescent
patients were evaluated, after restoration, with a
mean observation period of 4 years. Mean age at
surgery was 11.0 years. Clinical criteria assessed
tooth mobility, plaque and gingival conditions, probing pocket depths, and reaction to percussion. The
interproximal gingival papilla fill was assessed according to an index. Pathosis, pulp obliteration, root
length, and crown-root ratios were studied on standardized radiographs. The results showed that the
clinical variables for transplants did not differ from
those of the natural incisors, except for some increased mobility and more plaque in a few transplanted premolars. The interproximal gingival papillae adjacent to all transplanted teeth were normal or
slightly hyperplastic, and no interdental gingival
recession (black triangles) were seen. As expected,
all transplants showed varying degrees of pulp obliteration. The findings also demonstrated that tooth
transplantation has an inherent potential for bone
induction and reestablishment of a normal alveolar
process.
Orthodontic and restorative treatment for
autotransplanted teeth
Because the root of an autotransplanted premolar
continues to develop and a normal periodontal ligament
is established, such teeth can be moved orthodontically
like any other tooth that has erupted into occlusion. It is
generally recommended to wait for an observation
period of 3 to 4 months before orthodontic treatment is
started.
Premolar crowns can be reshaped to resemble
incisor morphology. We first make a direct composite
resin buildup and later replace it with a porcelain
laminate veneer (PLV). However, there are some drawbacks with the resin buildups, because it is difficult to
establish normal incisor width along the gingival margin, and the buildups tend to have a triangular crown
form. Furthermore, composites tend to discolor with
time. Both problems can be solved by using thin PLVs
instead (Fig 1, B). The 2 main reasons to avoid
cemented crowns in children and adolescents—that the
large pulp chambers limit preparation and that the
gingival retraction over time could lead to unesthetic
root display—are not valid for PLVs. The reflection of
286 Zachrisson, Stenvik, and Haanæs
American Journal of Orthodontics and Dentofacial Orthopedics
September 2004
Esthetic outcome and patient satisfaction
A comprehensive study comparing the esthetics of
22 autotransplanted premolars reshaped to incisor morphology with their natural, intact contralateral incisor
was made.5 Features considered important for esthetics
(color, soft tissue appearance, tooth morphology, and
position) were compared. Most of the transplanted teeth
matched the contralateral incisor, and most patients
were satisfied with the appearance of the transplant.
The distribution in set categories assessed professionally and by the patients was not significantly different.
However, the color and the gingival width of the
transplanted tooth were scored as different from the
natural incisor in almost half of the bilateral comparisons. A potential for esthetic improvement was identified, because suboptimal positioning and morphologic
transformation of the transplant were responsible for
the discrepancies. The findings demonstrated that interdisciplinary planning is important for successful esthetic results.
Multiple missing teeth
When 2 or more neighboring incisors are missing, a combination of premolar autotransplantation
and orthodontic space closure might be the optimal
treatment alternative. As discussed elsewhere,6 careful
detailing throughout the orthodontic progress and finishing stages to achieve optimal positioning and crown
inclination of all teeth, coupled with new techniques
and materials adapted from esthetic dentistry can, even
in these difficult treatment situations, restore natural
tooth shapes and sizes and provide normal gingival
texture and contours around all the teeth.
The potential for bone preservation in the mixed
dentition (before eruption of the canine) by premolar
autotransplantation was examined in a follow-up
study of 5 patients with alveolar cleft and 2 incisors
missing on the cleft side. The observation period was
2.5 to 7.5 years.7 The transplanted premolars were
placed in the central incisor region 14 to 26 months
after the bone grafting (cancellous bone chips from
iliac crest) to the cleft area. After premolar autotransplantation and space closure, the premolar and canine acting as the central and lateral incisors, respectively, were restored with composite resin buildups.
The results showed that, with properly timed alveolar
bone grafting, transplantation, and orthodontic space
closure, nonprosthodontic management of patients
with alveolar clefts is possible, even when 2 incisors
are missing on the cleft side.
Fig 3. Single implant-supported crown on left central
incisor. Note gingival papilla height on crown is lower on
distal than on mesial side.
Table. Comparison of outcome between autotransplantation of developing premolars and single-tooth implants after accidental loss of maxillary incisor
Transplant
“Biologic” replacement
Creates alveolar bone
Normal periodontal membrane
Adjustable position after
surgery
Erupts, in synchrony with
neighbors during continued
growth and eruption
Normal interdental gingival
papillae
Long-term observations (⬎40
years)
Implant
“Artificial” replacement
Needs alveolar bone
Ankylosed (osseointegrated)
Nonadjustable
Does not erupt
Frequently interdental gingival
recession (particularly with
2 neighboring implants)
Long-term observations (⬎10–
15 years) lacking
Autotransplantation, single-tooth implants, or
space closure
Osseointegrated implants are now the preferred
treatment alternative for many dentists when it
comes to replacing missing anterior teeth. Experience gained to date for survival of single-tooth
implants is favorable, with rates in multicenter studies of 90% at 10 years. However, clinical success
depends not only on persisting osseointegration, but
also on harmonious integration of the crown into the
dental arch. The clinical esthetic result for single
implants replacing maxillary incisors is sometimes
less than desired. The difficulties in obtaining a
natural marginal gingival contour are partly due to
the relationship between implants and the bone and
gingiva surrounding them. The reduction in osseous
scallop from facial to interproximal areas and lack of
difference in gingival heights above bone from facial
to interproximal, compared with natural teeth, can
lead to a flat gingival form. In a study comparing 21
implant-supported single-tooth replacements with
Zachrisson, Stenvik, and Haanæs 287
American Journal of Orthodontics and Dentofacial Orthopedics
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Fig 4. Orthodontic space closure to replace accidentally lost right central incisor. A, Lateral incisor has been
moved to midline. It is intruded and provided with thin
PLV (photo courtesy of Dr S. Toreskog). B, Right canine
is extruded, ground in incisal part, and has small hybrid
composite resin corner. First premolar is intruded and
has hybrid composite resin buildup in incisal part. Note
nearly natural appearance with symmetric marginal gingival levels.
their contralateral natural teeth,8 it was found, after a
mean observation time of 3 years, that the implantsupported crown had a lower height of the distal
papilla (Fig 3). The implant crowns were longer (1
mm), had more mucositis and bleeding on probing,
and had greater probing depths than the natural
incisors.
The challenge in treating patients with missing
maxillary incisors and any coexisting malocclusion is
how to achieve the best esthetic and functional results,
particularly in a long-term perspective. In this regard, a
comparison between some properties of transplants and
implants is relevant. The Table represents a direct
comparison of the 2 methods, and at least 6 differences
are evident:
Transplantation represents a biologic approach in
which the transplanted tooth germ retains the potential
to induce alveolar bone growth; the single implant is an
artificial method in which bone-regeneration techniques might be required when the alveolar bone
support is insufficient.
The transplant has a normal periodontal membrane
and can be moved orthodontically like any other tooth.
The osseointegrated implant is ankylosed to the bone,
and its position cannot be changed.
The transplanted tooth will erupt in synchrony with
the neighboring incisors during continued facial growth
and eruption of the teeth and adapts to functional
stimuli. The implant will not follow the neighboring
incisors vertically during tooth eruption at any age.
A normal marginal gingival contour is routinely
established around restored transplanted teeth (Fig 2);
this is not the case for single-implant replacements.
Several patients in Norway have been followed for
30 or more years, after having had premolars transplanted from 1 region of the mouth to another. Scientific long-term studies (more than 10 years) of implantsupported crowns in the esthetic zone are not available.
A major limitation of premolar transplants is that
the technique should be applied only in children who
have premolars that are still developing. Transplantation of premolars with fully formed roots and closed
apices is less successful and is regarded as an experimental procedure.9 Implants, on the other hand, should
be reserved for nongrowing adults.
A systematic analysis of orthodontic space closure as
a treatment alternative when a maxillary central incisor is
missing was recently made in a follow-up study (mean 5.7
years) of 20 consecutively treated patients.10 All patients
had received orthodontic treatment with the objective of
closing the space for the missing central incisor. Biologic
features and the clinical appearance of the recontoured
lateral incisor (test tooth) replacing the missing tooth were
compared with the neighboring intact central incisor
(control tooth). The patients’ opinions regarding the treatment and the result were recorded in a questionnaire. The
position of the examined teeth and the appearance of the
surrounding tissues were similar in the test and control
teeth. However, in some patients (25%), certain aspects of
incisor crowns recontoured with direct composite resin
buildups (such as the width at the gingival margin)
mismatched the appearance of the controls. No obvious
detrimental effects were observed on the radiographs.
Most patients expressed satisfaction with the treatment
result. Space closure treatment can be recommended if the
indications for it are present11 and careful attention to
detail is exercised during the orthodontic12 and restorative
treatment (Fig 4).
REFERENCES
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American Journal of Orthodontics and Dentofacial Orthopedics
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