*Corresponding author: Eftychia Pappa, National and Kapodistrian University of Athens, School of Dentistry,
Department of Operative Dentistry, Athens, Greece
How to cite this article: Papagiannis A, Pappa E, Chryssafidis C, Bogosian E and Vastardis H. Technological Advances in The Dental Management of
00106 Patients with Lesch-Nyhan Syndrome: A Case Report. Acad J Ped Neonatol. 2021; 10(2): 555839.. DOI: 10.19080/AJPN.2021.10.555839
Lesch-Nyhan syndrome (LNS) is a rare X-linked genetic disorder of purine metabolism , affecting the central nervous system . It is a perfect example of a well-established molecular disorder that is consistently linked to a complex behavioral pattern . The defective activity of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) [3,4], catalyzing conversion of the purines hypoxanthine and guanine to the nucleotides inosine monophosphate and guanosine monophosphate respectively, leads to the concentration of large amounts of hypoxanthime, xanthine, and uric acid in blood [3,4]. Epistasis between the mutated hypoxanthine phosphoribosyltransferase 1 (HPRT1) and the amyloid precursor protein (APP) genes has been recently suggested . The main tissues affected are brain, liver, and erythrocytes (megaloblastic anaemia is frequent; microcytic anaemia can also be present) [4,5].
The neurological symptoms include dystonia, choreoathetosis,
spasticity, hyperflexia and ballismus [1,6]. Behavioral clinical
symptoms involve mental retardation (mean IQ approximately 60
although, individual scores of IQ equal to 15 have been reported
), cognitive dysfunction and the compulsion towards selfmutilation
[1,6]. Lips, especially the lower one, cheeks, tongue and
fingers are mostly mutilated by biting.
The current case report describes a child with Lesch-Nyhan
syndrome who presented with self-injury of cheeks and lips and
was treated conservatively with intraoral splints and mouthguards.
Emphasis is given on the potential of digital dentistry in the
management of such cases, where compliance is absent.
A 5-year-old boy, previously diagnosed with LNS, was referred
to the Dental Clinic of the University General Hospital of Heraklion,
Crete, with self-mutilation of cheeks and tongue. He exhibited
hyperflexia, abnormal movements and spasticity, a condition
that worsened by increased tension and anxiety. Laboratory tests
revealed hyperuricemia, implying excessive purine production.
Intra- and extraoral examination revealed injured cheeks and lips.
Upper and lower intraoral impressions, from a resistant to
deformation material (polyvinyl-siloxane), were taken under
general anesthesia for the construction of appliances that could
prevent the self-injurious behavior. It was decided to fabricate
2mm thick upper and lower, soft on the inside and hard on the
outside mouthguards. After their delivery, behavioral symptoms
were alleviated, and self-mutilation ceased. Whenever it was
difficult for the patient to retain the appliance, an adhesive
material was also implemented. Unfortunately, splint damage
often occurred, requiring subsequent replacements. Furthermore,
after a 4-month period, the child started biting his fingers. A
mouthguard of 3mm thickness resembling a passive positioner
was constructed to prevent further trauma (Figure 1).
The problem raised with time was that even the polyvinylsiloxane
impressions were on the verge of permanent deformation.
General anesthesia could not be conducted again, due to renal
malfunction, a common finding in such patients. The solution
to this problem was sought in digital dentistry procedures.
The scanning of the initial plaster model provided us with a 3D
virtual model of the teeth and perioral tissues. This enabled us to
fabricate unlimited resin model casts, by 3D printing, that were
used for direct construction of any intraoral appliance, eliminating
the need for additional general anesthesia. Digital dental casts are
presented in Figure 2.
This case is an example of how dental technology and
computer-assisted components can facilitate the management
of complicated cases with minimal to no compliance. A similar
approach could involve the use of an intra-oral scanner under
mild sedation instead of general anesthesia. Three-dimensional
printing of the virtual models, or even the direct design and
fabrication of the splints and mouthguards by biocompatible
printing materials could facilitate treatment and establish new
ways of meeting patients’ needs.
In this case, we decided to select intraoral splints and modified
mouthguards as the preferred way to restrict the self-aggressive
behavior. Many methods have been proposed in the literature
for managing this condition. For the prevention of the lower lip
injury, due to sucking habits, the construction of a mouthguard
of 3mm thickness, of a soft inner and hard outer part has been
proposed . In case that a more stable appliance is necessary,
a lip-bumper constructed in a way that the distance between the
lower teeth and the lower lip does not allow sucking, can offer an
alternative solution . The combination of a mouthguard in the
upper jaw and a lip-bumper in the lower jaw has been associated
with positive behavioral modification .
A modified intraoral resin mouthguard has also been proposed,
presenting a hard side in contact with the teeth, to increase
retention, and a soft side outside, to prevent traumatic occlusion.
Any contact with the perioral tissues is removed, to increase its
stability . The use of acrylic splints with labially placed acrylic
arch, soft mouthguards, bite plates or lower lip guards have
been suggested as well [10,11]. Protection of fingers, hands and
forearms with bandages can offer an effective management of the
self-destructive behavior .
Drugs have been subscribed to prevent the self-injurious
behavior, but with questionable results. Allopurinol has been
extensively used to decrease the levels of uric acid to normal,
but the neurological and behavioral aspect of the syndrome was
not affected. Diazepam has also been used for relaxation of the
muscular system .
The last and most invasive approach to prevent self-mutilation
is extraction of teeth of both deciduous and permanent dentitions.
This should be recommended only in extreme cases, and in case
of significant medical complications [10,12]. Nonetheless, even
after the extraction of the deciduous dentition, new forms of selfaggressiveness
can be developed .
Less radical interventions such as the oral appliances could
be the first step in managing LNS cases, opting for a positive
behavioral modification. On this note, recent technology and
digital dentistry can make clinical work easier and more effective
for the patient. However, it has been argued  that deciduous
dentition extraction at the initial stage would be better in some
cases. Records of 5 patients with LNS treated conservatively
with mouthguards were analyzed. Dental extractions of all teeth
were eventually considered necessary in 4 out of the 5 cases. The
disfigurement of the face and tongue from self-biting was thought
more severe than the aesthetic effect of removing all the primary
dentition . Through this prism, the contribution of modern
technology to easier and better management of such cases is