Dental Implants in the Habilitation of Young Patients

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23
Dental Implants in the Habilitation
of Young Patients
Both the predictability and success of dental
implants in adult patients depend on the
quality and quantity of alveolar bone, treat-
ment planning, sound surgical technique,
optimal prosthodontic restoration, and long-
term oral hygiene (Brahim 2005). The same
factors also apply to the success of implants
placed in children, adolescents, or young
adults—referred to in this chapter as “young
patients.” The unique and critical difference
between treatment of pediatric and adult
patients is that the wildcard of craniofacial
growth and dento-alveolar development may
affect outcome unpredictably (Brahim 2005;
NIH 1988).
Growth is modulated by a complex inter-
action of many factors including, to name a
few, familial and genetic factors, trauma,
endocrine influences, acute and chronic ill-
nesses, and exposure to radiation therapy.
Determining the cessation of growth is dif-
ficult (Bjork 1963; Brahim 2005; Carmichael
and Sàndor 2008). In the author’s center a
combination of serial clinical examinations,
wrist carpal radiographs, and serial lateral
cephalograms taken 6 months apart are
used to assess the degree of skeletal matu-
rity of the jaws. The issue of growth and
estimation of its progress remains a complex
issue to this day (Carmichael and Sàndor
2008).
Placing implants in young patients is more
complicated than in adults. For one thing,
young patients may require general anesthesia
in order to manage their behavior. Moreover,
compliance with home-care instructions
and a child’s dexterity can constitute serious
impediments to the maintenance of a satisfac-
tory level of oral hygiene, which is critical in
most situations to ensure the long-term health
of the reconstructed dentition.
Recognition that dental implants can inhibit
growth (Kuröl and Ödman 1996; Ödman
et al. 1991; Thilander et al. 1995) and adap-
tation of the jaws (Bernard et al. 2004) have
led to dialogue in the literature surrounding
the earliest possible time at which implants
can be placed into a patient (Bishara et al.
1996; Carmichael and Sàndor 2008; Forsberg
et al. 1991; Oesterle and Cronin 2000;
Tarlow 2005). The author’s center has
adopted a number of general treatment plan-
ning principles governing management of
young patients requiring dental implants
(Sàndor and Carmichael 2008). They include
the following:
373
George K.B. Sàndor
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374 Osseointegration and Dental Implants
1. Young patients who require dental implants
to replace single or a few teeth receive
dental implants only after they attain skel-
etal maturity in order to avoid perturbing
growth of the jaws.
2. Patients with oligodontia are treated with
dental implants following the completion
of orthodontic therapy and the cessation
of skeletal growth.
3. Patients with global growth perturbations
such as those having been treated with
ablative surgery or having suffered severe
traumatic loss of multiple teeth, surround-
ing tissues, and extensive scarring may
have dental implants placed prior to skel-
etal maturation. Under circumstances such
as these, growth is abnormal and likely
to result in maladaptive compensatory
growth of undamaged parts of the maxil-
lofacial complex.
4. Implant treatment in young patients pro-
ceeds only if parent and child demonstrate
significant motivation to undergo complex
long-term treatment and a willingness to
maintain proper oral hygiene.
Clinicians should not underestimate the
weight of the psychological burden borne by
a child with a severe dental malformation
(Forsberg et al. 1991). Management must
include a humane understanding of the psy-
chological and socioeconomic impact of such
conditions on a patient and his or her family,
particularly when more than one child is
afflicted.
A common denominator of many dental
and craniofacial anomalies is congenital
absence of teeth or oligodontia. To the extent
that many acquired dental anomalies also
involve missing teeth, it is instructive there-
fore to anyone with an interest in the treat-
ment of congenital and acquired anomalies to
have an understanding of the subjective and
objective consequences of oligodontia or
acquired partial edentulism in young patients
(Fig. 23.1).
These consequences complicate therapy
and must be understood by the treating prac-
titioner (Table 23.1). Severe oligodontia may
reduce masticatory efficiency, resulting in
decreased alimentation and impaired nutri-
tion (Fig. 23.2).
A variety of malocclusions may present
together with oligodontia including retrogna-
thism, deficiency of vertical lower face height,
or prognathism. Such malocclusions are
Figure 23.1. Clinical photograph of a 14-year-old girl
with oligodontia with undermined aesthetics, poor self-
image, and a resultant lack of socialization. There is also
loss of lower vertical face height. The patient looks older
than her age.
Table 23.1. Consequences of oligodontia.
Undermined cosmesis
Poor mastication
Malocclusion
Hypoplasia of crowns
Poor orthodontic anchorage
Ankylosis of primary teeth
Disruption of alveolar growth
Agenesis of alveolus
Resorption of alveolus
Depleted periodontium
Periodontal trauma
Attrition with dentine and pulp exposure
Extrusion
Insufficient vertical dimension of occlusion
Insufficient intermaxillary space
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Chapter 23 Dental Implants in Habilitation 375
Figure 23.2. Severe loss of vertical height due to attri-
tion in this oligodontia patient complicated by over-
eruption of the unopposed permanent teeth. Such
over-eruption makes implant hardware difficult to posi-
tion, not allowing the prosthodontist the opportunity to
camouflage metal and hardware.
subject to excessive wear of both the mixed
dentition and the depleted permanent denti-
tion (Fig. 23.3).
Tooth crown form in patients with severe
oligodontia may be hypoplastic (Fig. 23.4).
Oligodontia may result in severely deficient
orthodontic anchorage, which may greatly
prolong treatment time and compromise
outcome (Fig. 23.5).
Figure 23.3. Oligodontia patients may have a variety of
malocclusions with severe attrition of both the remaining
deciduous teeth and what permanent teeth may exist in
the mouth.
Figure 23.4. Oligodontia may be accompanied by teeth
that have hypoplastic crown forms, presenting a variety
of restorative and treatment planning challenges.
Figure 23.5. Patterns of oligodontia may result in
severely reduced orthodontic anchorage, which may
greatly prolong treatment time and could result in com-
promised results.
Traumatic loss of maxillary teeth is common
in young patients. Restoration of edentulous
spaces left by traumatic tooth loss should be
delayed until skeletal maturity is attained
(Ledermann et al. 1993). In a study of 42
implants in 34 growing patients with a mean
age of 15.1 years, there was a 90% rate of
successful osseointegration, while the major
complication noted was the failure of the
ankylosed dental implant to match the verti-
cal growth of the alveolus of the adjacent
teeth, resulting in submergence and infraoc-
clusion of the restored dental implants
(Ledermann et al. 1993). The patient in Figure
23.6 demonstrates submergence of an implant
placed at the site of the maxillary left central
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376 Osseointegration and Dental Implants
incisor before the cessation of skeletal growth.
The resulting discrepancy of gingival margins,
between the natural tooth, which has contin-
ued to erupt, and the implant, which tends to
relatively submerge as would an ankylosed
tooth, is very difficult to treat (Sàndor and
Carmichael 2008).
The authors endeavor to adhere to a stand-
ard protocol in the management of complex
anomalies involving missing teeth and requir-
ing dental implants as part of their overall
treatment (Table 23.2). These cases have
responded well to such interdisciplinary man-
agement and include many conditions
complicated by the agenesis or loss of teeth
(Table 23.3).
Growth must always be considered when
implant-supported prostheses are inserted
into growing children. Patients with severe
oligodontia such as in ectodermal dysplasia
may be treated at a young age with dental
implant-supported fixed prostheses (Brahim
2005; Guckes et al. 1991, 2002). One past
attempt to minimize potential growth distur-
bance was to section the prosthesis placed
across the anterior mandible in the region of
the symphysis of the lower jaw (Figs. 23.7–
23.11), especially in patients with resections
for tumor ablation.
Figure 23.6. A 17-year-old male demonstrating sub-
mergence of an implant-supported crown at the site of
the maxillary left central incisor placed at 15 years
of age.
Table 23.2. Clinical protocol.
Multidisciplinary assessment
Orthodontic treatment
Orthodontics alone
Orthognathic surgery
Grafting of cleft alveolus in alveolar cleft
patients
Determination of skeletal maturity
Peri-implant alveolar bone grafting
Implant placement
Prosthodontic habilitation
Follow-up
Table 23.3. Some syndromes managed with dental
implants.
Binders Syndrome
Cleidocranial Dysplasia
Crouzon’s Syndrome
Ectodermal Dysplasias
Epidermylosis Bullosa
Fibrous Dysplasia
Familial Odontodysplasia
Gorlin Syndrome
Hemifacial Microsomia
Lateral Facial Dysplasia
Long Face Syndrome
Pierre Robin Sequence
Singleton-Merton Syndrome
Trisomy 21
Turette’s Syndrome
Incontinentia pigmenti
Treacher Collins
Figure 23.7. Dental implants placed into the anterior
mandible of an 8-year-old patient with hypohydrotic
ectodermal dysplasia.
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Chapter 23 Dental Implants in Habilitation 377
These children can be severely debilitated
by their tumor resections and so are subse-
quently treated with implant-supported resto-
rations during the mixed dentition phase,
which is a period of intense growth (Bjork
1963; Brahim 2005; Sàndor et al. 2008). It
was assumed that the prosthesis could be split
in the midline to accommodate mandibular
growth in the transverse dimension. Sub-
sequent experience has shown this to be
unnecessary (Fenton et al. 2007; Sàndor et al.
2008). Not a single patient treated with an
implant-supported suprastructure that was
split in the midline of the mandible has devel-
oped a diastema in the midline, even if he or
she was actively growing. The author’s center
has therefore stopped splitting suprastruc-
tures in the midline of the mandible solely for
the reasons of growth.
The alveolus where the dental implants are
placed is not expected to grow vertically
(Ödman et al. 1991). As the deciduous molars
exfoliate and the permanent molars erupt, the
alveolus will grow vertically in the areas of
permanent tooth eruption. This may result in
a vertical discrepancy between the heights of
the posterior and anterior mandible where the
resection has been performed and the implants
were placed. This growth discrepancy may
necessitate serial remakes of the implant-
borne prosthesis to accommodate the differ-
ential vertical growth in the alveoli and the
dynamically erupting dentition in the maxilla
Figure 23.8. The planned restoration is one of a sec-
tional nature with a gap at the midline of the mandible.
This photograph shows the left part of the restoration on
the model. This represents an attempt to avoid interfer-
ence of mandibular growth by not crossing the midline
of the lower jaw. The author’s centers have stopped using
prosthesis that were sectioned solely for the reasons of
growth.
Figure 23.9. The implant-borne fixed restoration in its
entirety on the dental cast.
Figure 23.10. The first section on the left is installed
into the mouth.
Figure 23.11. Labial view of the installed mandibular
anterior prosthesis 2 years after delivery.
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378 Osseointegration and Dental Implants
and posterior mandible. In the meantime
these prostheses help the child adapt func-
tionally and aesthetically, which is especially
important to the development of self-esteem
in the pediatric patient, both at school and
socially (Fenton et al. 2007; Hunt et al.
2005).
Growth following implant placement may
occur at the dental alveolus or in other areas
of the mandible, for example, in cases of man-
dibular asymmetry and prognathism. Man-
dibular growth in such patients is aberrant
and may occur once growth is assumed to be
complete. Figures 23.12–23.21 illustrate the
Figure 23.12. Frontal facial photograph of 16-year-old
male with anhydrotic ectodermal dysplasia at the time of
presentation.
Figure 23.13. Panoramic radiograph of patient in Figure
23.12 showing severe attrition of teeth in patient with
severe oligodontia.
Figure 23.14. Frontal photograph of patient from Figure
23.12 now 18 years of age and restored with implant-
supported prostheses.
Figure 23.15. Anterior view of occlusion at the time of
prostheses insertion and delivery.
Figure 23.16. Occlusal view of maxillary implant-
supported superstructure.
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Chapter 23 Dental Implants in Habilitation 379
Figure 23.17. Occlusal view of maxillary overdenture
prosthesis.
Figure 23.18. Occlusal view of mandibular fixed
prosthesis.
Figure 23.19. Frontal photograph of patient at 21 years
of age with newly developed mandibular asymmetric
prognathism. Note the deviation of the chin to the right.
Figure 23.20. Anterior view of asymmetric malocclu-
sion of the prostheses with skeletal and dental midlines
of the mandible shifted to the right with a right buccal
segment crossbite, due to late mandibular growth.
Figure 23.21. Panoramic radiograph showing four
newly placed implants to replace those fixtures failing
from occlusal overload from the newly developed
malocclusion.
case of a 19-year-old male who developed
an asymmetric mandibular prognathism
with laterognathia due to late mandibular
growth.
Some of the dental implants in the right
mandible became overloaded due to the asym-
metric malocclusion and were lost. Late man-
dibular growth can result in implant overload
and consequent implant fixture failure.
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380 Osseointegration and Dental Implants
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