Dental Asia May/June 2020

Clinical Feature
Traditional techniques correcting Literature review
overbite features in all Orthodontic literature had described
malocclusions have been known myriad approaches for overbite correction.
to be quite complicated, and
challenging
to orthodontists. Strong
mechanical background,
sophisticated appliance
designs, diligent patient’s
cooperation and multiple
By Dr. Suhail Khouri and Dr. Derek Mahony
adjustment visits over a long
treatment time are crucial
elements for successful
treatment prognosis of this
dento-alveolar deformity.
Despite the overwhelming advances that Some approaches used fabricated loops,
already modernised many orthodontic helices and springs made of stainlesssteel
wires to create the bite-opening
concepts, techniques, and practice,
nonetheless modalities correcting overbites force system 3,10-14 . Others used functional
did not witness significant advances. appliances with and without headgears 4,5 ;
while severe skeletal cases were managed
To date super elastic wires have only with surgical approaches 6-9 .
been principally used in their straight
prefabricated form for the sole purpose of Ever since the inception of their use in
initial teeth levelling, until the Bendistal Pliers orthodontic practice, the impossibility
demonstrated their unique ability to cinchback
and bend NiTi wires, for the first time 1 . restricted orthodontists to use them only
of bending super elastic archwires has
The possibility of placing permanent V-bends in their prefabricated straight arch forms
on super elastic archwires intraorally armed in initial teeth levelling. Subsequently they
orthodontists with full control of super couldn’t use the superior elasticity of those
elastic wires and resurrected their advanced wires in other orthodontic tooth moments.
mechanical properties that were overlooked They could not even bend distal ends of
after performing initial teeth alignment. By such wires without annealing that ruins
providing light and consistent force, these the entire wire’s resiliency and defeats the
bends could effectively move groups of only purpose of their use. Many researchers
teeth in both transverse and vertical planes demonstrated the validity of using intrusion
of space.
appliances, helices and springs made of
super elastic wires in their prefabricated
Clinical application of this concept has forms 15-17 . Despite this success, however,
resulted in evolution of new techniques that the inability to bend these wires made it
showed efficiency in correcting a multitude of impossible to customise the costly intrusion
major orthodontic dentoalveolar deformities appliances, and resulted in the limited use
with unprecedented simplicity, convenience of prefabricated elastic appliances and even
and time savings 2 . This article elaborates wires.
on one new technique that corrects dental
and skeletal deep overbite mostly featured Bending titanium wires without annealing
in Class I and Class II malocclusions using or breakage requires specially designed
simple routine wire adjustments during pliers. Khouri developed one such set of
patient’s regular visits.
pliers – Bendistal Pliers – and subsequently
Part I: Correcting Excessive
Overbites with V-Bend Activations
of Super Elastic Wires
This two-part article describes a simple, effective and clinically
applicable alternative bite-opening technique using V-bends on
super elastic wires that are created by new orthodontic pliers.
showed how clinicians could use them
for many intraoral sundry super elastic
wire activations that moved segments of
teeth and corrected overbites, crossbites,
expanded and constricted
dental arches, tip backs and
rotate molars 2 .
The mechanical principles
underlying bite-opening
techniques have been
well established and
appreciated in literature 3,
16, 19, 20
. Dake and Sinclair 13
reported that intrusions
and extrusions achieved by both Ricketts
and modified Tweed techniques remained
stable. Hans et al 18 compared the efficiency
of the headgear and bionator with fixed
appliances in bite opening and found that
both approaches produced incisor intrusion
combined with skeletal mandibular changes
that contributed to the correction of deep
overbites. Burstone 3 has advocated that not
all patients with overbites require incisor
intrusion exclusively; rather, some require
posterior teeth extrusion to open their bite.
He presented upright intrusion springs that
intrude anterior teeth with minimal effect
on posterior teeth. He recommended spring
appliances with low load deflection rates
to produce the optimal intrusive forces.
Sander et al 16 described intrusion mechanics
completed with NiTi uprighting springs with
low load deflection rates that could intrude
incisors a magnitude of 7mm.
Shroff et al 11 found it difficult to correct
deep overbites when accompanied with
flared incisors by conventional orthodontic
therapies. They subsequently recommended
the Burstone segmented arch approach for
achieving precise vertical and horizontal
simultaneous moments of teeth. Davidovitch
and Rebella 12 described an intrusion
archwire that uses only tip back bends
close to molars, to achieve bite opening.
Nanda has also described appliance systems
and biomechanical techniques for incisor
32
DENTAL ASIA MAY / JUNE 2020