METHODS
Design and Subjects
The experimental protocol was a randomized trial with a
single-blind design. There was no communication between
the therapist in charge of the intervention and the therapist
who performed the measurements. To measure the
difference in craniocervical posture means (seated and
standing) from preintervention to postintervention of 2º
(SD, 1.50º), for an α value of .05 and a statistical power of
80%, a sample size of 12 subjects per group was necessary
(software: Tamaño de la Muestra 1.1, Pontificia Universidad
Javeriana, Bogotá, Colombia). Students of the School
of Nursing, Physiotherapy, and Podiatry of the University
of Seville were selected by the main author based on
nonprobabilistic convenience sampling according to the
following criteria: (i) age between 18 and 25 years old; (ii) a
history of having used orthodontics for at least 1 year; (iii)
absence of symptoms in the cervical spine, upper limbs, and
craniofacial area within the past 4 weeks previous to data
collection; and (iv) willingness to participate in the study as
declared in signing the informed consent form. The
exclusion criteria were (i) having history of a whiplash
injury; (ii) a history of degenerative disorders of the central
and/or peripheral nervous system; (iii) a history of cranial
vault, craniofacial, temporomandibular joint, or any level of
spinal fractures and/or surgery; (iv) having a history of
osteitis or cranial-vault, craniofacial, or temporomandibular
joint rheumatic or tumoral diseases; (v) receiving soft tissue
therapy within the year before the study; and (vi)
consumption of analgesics or anti-inflammatory drugs
within 48 hours before data collection. The sample group
consisted of 24 subjects (n = 24), 5 men and 19 women,
mean age 21 ± 1.78 years (18-24 years). Subjects were
divided randomly into a sham group (SG) (n = 12) and an
experimental group (EG) (n = 12). Randomization was
done by means of sealed opaque envelopes by the therapist
who performed the interventions. The process of intervention
and data collection was conducted in the School of
Physiotherapy and Podiatry at the University of Seville
from June to September 2010 by 2 physiotherapists with
more than 10 years of health care experience, maintaining
similar ambient conditions on the successive days. The study received approval and was designed conformed to the
guidelines of the Ethical Committee of Experimentation,
University of Sevilla, and it has been registered in the
Australian New Zealand Clinical Trials Registry with
registration number ACTRN12611001028998.