Dental and skeletal changes after intra-oral molar distalization using a “Distal Driver” appliance: a pilot study

frequent consequence of early loss of deciduous molars
indicating distalisation of the mesialised molar tooth. A
number of methods using either extra-oral appliances
or intra oral appliances of various types have been
suggested. While extra-oral appliances exert a high but
intermittent force many of the intraoral ones deliver a
modest, though constant, force and demands no patient
cooperation. Aim of study. To investigate the effect of
an intra-oral fixed appliance (Distal Driver) based
on a NiTi spring incorporating also a standardised
anchorage unit on the position of the maxillary first
molar as well as on the facial skeleton and the dentition
in general. Material and methods. The experimental
group comprised 6 child patients exhibiting a distal
molar relationship (Unilateral or Bilateral) of at
least ½ premolar unit. The mesialised molars were
distalised by means of a “Distal Driver” exerting a
force of 150 gm for a period of 3-4 weeks. Anchorage
was created by a fixed modified palatal bar cemented
on the premolars supporting an acrylic palatal button
ad modum Nance. The clinical situation was recorded
before and after molar distalisation by means of study
casts, cephalograms, panoramic radiographs as well
as intra-oral photographs. The distalisation of the
molars as well as the effect on anchorage teeth was
quantitated on digital models derived from the plaster casts. Evaluation of the observed distal and vertical
changes in molar position was performed on the
lateral cephalogram. Results. Cast analysis showed
a clear distalising effect on the maxillary first molars
ranging from 1.25 mm to 6.18 mm as well as mesial
movement of the premolar anchorage teeth from 0.46
mm to 5.55mm. The cephalometric analysis revealed
a first molar distalisation of 0.9 mm to 5.6 mm though
again with a mesial movement of the first premolar
varying from 0.5 mm to 3.7 mm. A clear distal tipping
of the first and second molars simultaneously with a
mesial tipping of the first premolars was also recorded.
Conclusion. The Distal Driver constitutes an efficient
method of maxillary molar distalisation though is
often accompanied by a distal rotation of these teeth
and a mesial tipping of the anchorage premolars.
Careful monitoring of anchorage loss is necessary if
good results are to be achieved.