Effect of Palatal Expansion and Up-Locker Activator on Sleep Architecture and Pharynx Dimensions in Children
Phase: NA
Conditions: Breathing Disorder During Sleeping, Sleep Habits
Sponsor: CES University

Effect of palatal expansion and Up-Locker Activator on sleep behavior and 
architecture and pharynx dimensions in children with Sleep Disordered 
Breathing 
 
 
 
Claudia Restrepo-Serna 
Sandra Kahn 
David Gozal 
 
 
 
 
 
Protocol 
 
 
 
 
 
 
 
Universidad CES 
Medellín, Colombia 
May 14th 2025 
 
 

INTRODUCTION 
Sleep quality and duration are critical determinants of health, contributing to optimal 
cognitive function, memory consolidation, and overall neurodevelopment children1. 
Adequate respiratory function plays a pivotal role in maintaining healthy sleep 
patterns, and quality and, consequently, children's quality of life2. 
There is growing evidence that Obstructive Sleep Apnea (OSA)3 and, even  sleep 
disorder breathing (SDB) are associated with a wide variety of adverse outcomes in 
children, both systemic and neurocognitive4. Even though there are controversies in 
the literature, about the affection of sleep stage architecture in the presence of SDB 
and/or OSA5, arousal is an important defensive mechanism against sleep disordered 
breathing, leading to sleep fragmentation6.  The most frequently used overnight 
polysomnographic metric for evaluating the severity of SDB is the apnea-hypopnea 
index (AHI). This index serves as a composite score that combines the total number 
of obstructive and central apneic events along with the total number of hypopneas 
experienced per hour of sleep7. 
Orthodontic interventions aimed at modifying hard palate morphology, such as the 
Hyrax appliance, have demonstrated efficacy in expanding the transverse 
dimensions of the hard palate and enhancing the dimensions of the upper airway up 
to 30%8,9, and thus, improve sleep quality. Previous studies evaluated the effect of 
semi-rapid maxillary expander (SRME) on sleep architecture6.  SRME treatment 
almost normalized sleep architecture and improved sleep respiratory disturbances; 
however, sleep structure and respiratory parameters did not completely recover6. 
These results may stem from the fact that isolated palatal expansion might not fully 
address functional factors like tongue posture and orofacial stability. Poor tongue 
posture—characterized by a downward position during both rest and activity—
hinders the development of sufficient suction and the preservation of Donders' 
space. This can lead to increased inflammation in the upper airway10,11. 
The proposed therapeutic approach using the Hyrax appliance in combination with 
the Up-Locker vacuum activator offers the potential not only to expand the palatal 
and dental arches but also improve the resting posture of the tongue11. By restoring 
negative pressure in the upper airway through vacuum activation, this combined 
intervention may enhance orofacial function12, optimize airway dimensions13, reduce 
SDB14, improve sleep physiology, and stabilize treatment outcomes with maxillary 
expansion11, by establishing adequate tongue posture at rest and function15.  
The hypotheses of this investigation are that intervention with Hyrax + Up-Locker 
vacuum activator has better effect on improving airway dimensions, and  sleep 
behavior (reduction of snoring, scores of SDB, night wakings and daytime 

sleepiness) and sleep architecture (reducing sleep latency more than 12 minutes, 
and AHI to less than 5. Additionally, it is expected to increase the percentage of 
Rapid Eye Movement (REM) sleep more than 3%, no-REM (nREM) sleep stage 3 
more than 5%, and total sleep time more than 30 minutes) compared with treatment 
with the treatment with Hyrax alone. Thus, the aim of the present investigation is to 
evaluate the effectiveness of the combined intervention of Hyrax + Up-Locker 
vacuum activator in reducing snoring and enhancing nasopharynx and nasal airway 
dimensions, improve sleep behavior and sleep architecture, specifically by 
measuring improvements in daytime sleepiness, SDB, night wakings, sleep latency, 
apnea-hypopnea index, percentages of REM and non-REM sleep stage 3, and total 
sleep time, in comparison to treatment with Hyrax alone. 
METHODOLOGY  
 
A prospective, single-blind, randomized controlled clinical trial will be conducted. 
Children aged 6 to 8 years will be recruited from the clinics of the postgraduate 
program of Pediatric Dentistry and the private practice of one of the investigators 
(CR). 
 
The sample size will be calculated based on the differences reported by Sökücü et 
al.16, assuming a 95% confidence level, 80% power, and a 20% treatment difference. 
According to the analysis, 17 participants per group (total n = 34) will be required.  
 
Inclusion Criteria  
 
Presence of sleep-disordered breathing symptoms, with a minimum score of 6 on 
the Children’s Sleep Habits Questionnaire (CSHQ)17—which will be described below 
in the outcome measures—documented snoring recorded by SnoreLab™ for at least 
five consecutive days, and transverse maxillary deficiency of at least 5 mm, with a 
normal superior intermolar distance defined as a minimum of 40 mm (measured 
between the mesiopalatine cusps of teeth 16 and 26). 
 
SnoreLab™18 will be used as a validated mobile application created to monitor and 
analyze snoring behavior, providing insights into sleep patterns and potential 
underlying sleep disorders. Employing advanced sound detection technology, the 
app will record snoring episodes during the night, offering detailed feedback on the 
frequency and intensity of snoring. Users will be required to demonstrate valid 
recordings for at least 50% of each night, with data collection continuing until five 
nights of recordings are achieved. To qualify for inclusion in the study, participants 
will need to exhibit snoring—whether light, loud, or epic—across these five nights. 
 

Exclusion Criteria 
 
History of previous treatment for OSA (including tonsillectomy and adenoidectomy), 
overweight or obesity (Body Mass Index (BMI) at or above the 85th percentile for 
their age and sex), chronic systemic diseases unrelated to upper airway respiratory 
alterations (e.g., chronic cardiopulmonary or neuromuscular diseases), facial 
malformations (e.g., syndromes with facial or cleft lip/palate anomalies, or clinically 
evident palatal malformations), presence of dental caries, prior treatment with 
maxillary orthopedics or orthodontics, and failure to comply with scheduled control 
visits. 
 
Weight will be measured at the Universidad CES dental clinic or the private practice 
of one of the investigators (CR) using a standard physician's scale, ensuring that the 
children are dressed in light clothing and not wearing shoes, with the scale providing 
a precision of 0.1 kg. Height will be assessed using a wall-mounted height board, 
adhering to specific criteria: children will stand barefoot, with their heels together, 
and their heels, buttocks, shoulders, and head in contact with the wall while 
maintaining a neutral gaze. Measurements will be recorded to the nearest 0.1 cm. 
BMI will then be calculated using the formula kg/m². 
 
Participants will be randomly assigned using a random number generator in 
REDCap™ to one of two groups: Group 1 (Control group: Treatment with the Hyrax 
expansion appliance alone) or Group 2 (Intervention group: Treatment with the 
Hyrax appliance in combination with the Up-Locker vacuum activator). 
 
Intervention 
 
For both groups, the semi-rapid maxillary expansion (SRME) will be performed using 
a Hyrax device with a Leone™ standard expansion screw for all children. Bands will 
be placed on the maxillary first permanent molars, and a frame containing the 
maxillary canines and primary first molars will support the expander. All expanders 
will be constructed by the same expert technician. In both groups, the expander 
screw will be activated a quarter turn twice a day for the first 7 days, followed by 
once a day until the palatal cusp of the upper molar comes into contact with the 
buccal cusp of the lower molar. After the active phase, the expanders will remain in 
the oral cavity for 4 months for retention. 
 
Patients in Group 2 will receive a standardized training device (Up-Locker Vacuum 
Activator from Forwardontics™, approved by the FDA) immediately after completing 
the retention period and removing the expansion Hyrax device. Patients will be 
instructed to gather saliva while positioning the Up-Locker vacuum activator between 

their front teeth and lips, using a mirror to monitor the placement of the membrane 
within the funnel. During the swallowing of saliva, negative pressure formation will 
be observed with the Up-Locker vacuum activator by the inversion of the membrane 
into the funnel. They will be informed that the objective of the treatment will be to 
establish a nasal breathing pattern and a tongue resting posture against the palate 
to help stabilize both the tongue and the soft palate. Patients will be advised to refrain 
from creating excessive negative pressure during the exercises to prevent potential 
adverse effects related to pressure on the gums. After instruction, the patients will 
undergo 30 minutes of daily home training during the first week, 60 minutes daily 
during the second and third weeks, followed by 120 minutes daily until completion of 
a 90-day program. The recommended timeframe for usage will be during the 
afternoon while watching TV or reading, or in the evening before rest. The 
investigator (CR) will perform revisions of adequate usage of the device every 4 
weeks. 
 
 
Outcome Measures 
 
Sleep Behavior 
 
Sleep behavior will be evaluated using the validated CSHQ17, which consists of a 
35-item questionnaire administered to parents, asking them to report their child's 
sleep behaviors and patterns over the last typical week. The instrument is designed 
to address significant clinical sleep complaints commonly observed in this age group 
and will provide data on the following subscales (with score ranges in parentheses): 
Bedtime Resistance (6–36), Sleep Onset Delay (1–3), Sleep Duration (3–9), Sleep 
Anxiety (4–12), Night Awakenings (3–9), Parasomnias (7–21), Sleep Disordered 
Breathing (3–9), Daytime Sleepiness (8–24). Each item on the questionnaire will be 
rated on a three-point scale: "usually" (5–7 times a week) = 3, "sometimes" (2–4 
times a week) = 2, and "rarely" (0–1 time a week) = 1. A composite score will be 
computed as the sum of scores on the 33 items across all subscales. A total score 
of 41 will be considered the clinical cut-off, indicating a potential risk of sleep 
problems. 
 
Sleep Architecture 
 
All children in both the control and intervention groups will undergo a one-night PSG 
study in a sleep laboratory in Medellín, Colombia, before treatment (T0) and at the 
end of treatment for the intervention group (T1, nine months after initiating treatment 
for both groups). The sleep study will utilize a sleep recording system and dedicated 
scoring software (Neuron-Spectrum-65/PSG system™, Neurosoft Ltd. Ivanova, 

Russia). The measurements will be conducted between 9:00 pm and 6:00 am for all 
participants, with audio and video signals recorded in parallel. A nasal flow cannula 
and a thermistor respiratory monitor will record respiration, while a finger pulse 
oximeter will monitor blood oxygen saturation (SaO2). All electrodes and sensors 
will be installed by a trained research team. 
 
The sleep architecture will be evaluated according to the AASM Manual for the 
Scoring of Sleep and Associated Events19. The following measures will be taken: 
 
- Total Sleep Duration (TSD): Cumulative time (in hours) spent in non-REM (nREM) 
stages 1, 2, and 3, and Rapid Eye Movement (REM) sleep from sleep onset to lights-
on time. 
 
- Sleep Onset Latency (SOL): The elapsed time between lights-out and the first 
occurrence of any sleep stage other than a stage of awakening. 
 
- Time and Proportion Spent in Each Sleep Stage: Cumulative time and 
proportion of sleep spent in each sleep stage (nREM stages 1, 2, and 3 [N3 and N4 
will be grouped] and REM sleep) from sleep onset to lights-on time. 
 
-Arousals/Hour during REM and nREM sleep: 3-5 seconds of arousal (abrupt 
alterations of oscillatory patterns, characterized by low-voltage fast-rhythm EEG 
oscillations during REM and nREM sleep). 
 
Airway dimensions  
 
The dimensions of the airway will be measured using lateral cephalometric 
radiographs. All x-rays will be taken with an Orthophos Plus Ceph™ for lateral 
cephalograms in children from both groups before the start of treatment (T0) and 
after the conclusion of the treatment period in the intervention group (T1)  
 
The measurements will include20: 
 
- ad1-PNS: The lower nasopharyngeal airway space will be measured in millimeters 
between the point ad1 (the lower adenoid point, which is the most prominent point 
of the pharyngeal tonsil, drawn in the PNS-Ba plane) and PNS. 
 
- ad2-PNS: The upper nasopharyngeal airway space will be measured in millimeters 
between the point ad2 (the superior adenoid point, which is the most prominent point 
of the pharyngeal tonsil, drawn perpendicular to the S-Ba line extending to the PNS 
point) and PNS. 

 
- SPAS: The superior posterior airway space, representing the width of the airway 
in the upper part of the pharynx, specifically behind the soft palate, will be measured 
as the distance between the posterior pharyngeal wall and the dorsal surface of the 
soft palate, parallel to the palate horizontal plane. 
 
- MAS: The measurement for the space of the airway corresponding to the upper 
glossopharynx will be taken, which represents the width of the airway along a line 
parallel to the palatine plane passing through point P (the extreme point of the soft 
palate). 
 
- IAS: The inferior airway space will be evaluated behind the tongue base in the 
glossopharynx, traced along a line parallel to the palatine plane through the 
intersection of the jaw and the airways. 
 
Additionally, panoramic radiographs will be obtained using an Ortopantomograph™ 
in children from both groups before (T0) and after the end of the treatment time in 
the intervention group (T1) to calculate the anterior nasal two-dimensional area. The 
shape of the anterior nasal space (radiolucent area) will be outlined by one examiner, 
and the program (Image J for PC, Softonic™) will subsequently determine the area 
in terms of pixels. 
 
Statistical Analysis 
 
Data will be analyzed using IBM SPSS Statistics version 27™. Descriptive statistics 
will summarize demographic and clinical characteristics. T-tests and Mann-Whitney 
tests will be employed to compare outcome measures between groups. A 
significance level of p < 0.05 will be applied to all comparisons. The Shapiro-Wilks 
test will be utilized to determine the normality of the variables. 
 
INFORMED CONSENT 
 
Informed Consent for Participation in a Clinical Study 
 
Study Title: Evaluation of Treatment Options for Children with Sleep-Disordered 
Breathing 
 
Principal Investigator: Claudia Restrepo-Serna, Postgraduate Program in 
Pediatric Dentistry, Universidad CES 
 
 

You are being invited to participate in a clinical research study regarding treatments 
for children aged 6 to 8 years with sleep-disordered breathing. This document aims 
to provide you with information to help you decide whether you would like your child 
to participate. Your participation is entirely voluntary, and you may choose to 
withdraw at any time without any consequences. 
 
Purpose of the Study: 
 
The purpose of this study is to evaluate the effectiveness of two treatment 
approaches for children experiencing symptoms of sleep-disordered breathing. This 
study aims to gather data on sleep behavior, sleep architecture, and airway 
dimensions before and after treatment. 
 
Study Procedures: 
 
If you agree for your child to participate, the following will take place: 
 
1. Recruitment: Your child will be recruited from our clinics based on specific 
inclusion criteria, including the presence of sleep-disordered breathing symptoms, 
documented snoring, and transverse maxillary deficiency. 
 
2. Screening: Your child will undergo screening to determine eligibility. This includes 
completing the Children’s Sleep Habits Questionnaire (CSHQ) and monitoring 
snoring episodes using the SnoreLab mobile application for five consecutive nights. 
 
3. Random Assignment: Eligible participants will be randomly assigned to one of two 
groups: 
 
   - Control Group: Treatment with the Hyrax expansion appliance alone. 
   - Intervention Group: Treatment with the Hyrax appliance and an Up-Locker 
vacuum activator. 
 
4. Treatment: All children in both groups will have a Hyrax device fitted. This 
appliance will be activated for a specified period, followed by a retention phase. The 
intervention group will additionally receive training on using the Up-Locker vacuum 
activator, aimed at promoting nasal breathing and stabilizing the tongue posture. 
 
5. Data Collection: Throughout the study, your child will undergo various 
assessments, including: 
   - Questionnaire about sleep behavior. 

   - One-night polysomnography (PSG) study before (baseline) and after (end of 
treatment, approximately nine months later) treatment. 
   - Lateral cephalometric radiographs to measure airway dimensions before and 
after treatment. 
   - Panoramic radiographs to measure the anterior nasal area. 
 
Confidentiality: 
 
Your child's participation in this study and all collected data will be kept confidential. 
All data will be de-identified to ensure privacy. The study findings may be published 
in scientific journals or presented at conferences, but individual identities will not be 
disclosed. 
 
Potential Risks: 
 
Participation in this study may involve some risks, including: 
 
- Discomfort associated with wearing the dental appliances. 
- Possible slight discomfort during the PSG study and imaging procedures. 
- The risk of feelings of anxiety or distress while engaging in assessments or 
treatments. 
- Radiation from dental x-rays. Strict control of the radiation generated by the 
equipment will be implemented, and the X-rays will be taken with all necessary 
protective measures. 
 
Potential Benefits: 
 
While there may be no direct benefits to your child from participating in the study, 
the information gained may improve understanding and treatment options for 
children with sleep-disordered breathing. 
 
Voluntary Participation: 
 
Your consent for your child to participate in this study is entirely voluntary. You have 
the right to withdraw your child from the study at any time without any effect on your 
child's future treatment. There will be no penalties or loss of benefits if you or your 
child chooses to withdraw. 
 
 
 
 

Contacts for Questions: 
 
If you have any questions regarding this study or your child's participation, please 
contact: 
- Principal Investigator:  
Claudia Restrepo-Serna 
+573108455592 
crestrepos@ces.edu.co 
 
Consent Statement: 
 
By signing below, you acknowledge that you have read and understood the 
information provided above, and you agree for your child to participate in this study. 
 
Parent/Guardian Name: __________________________________ 
 
Child's Name: __________________________________________ 
 
Signature: ______________________________________________ 
 
Date: _________________________________________________ 
 
Thank you for considering participation in this important study. 
 
 
 
 

ASSENT FORM FOR CHILDREN PARTICIPATING IN A SLEEP STUDY 
 
Hello!  
We are doing a study to learn more about how to help kids sleep better. This is 
important because good sleep helps you think, remember things, and feel good 
overall.  
 
What is this study about?   
In this study, we want to find out if using two special dental devices will make your 
sleep quality better than using just one device. We will help kids who have 
breathing problems when they sleep, which can cause snoring or waking up a lot at 
night.  
 
What will happen if you join this study?  
- If you agree to join, you will be asked to fill out a form about your sleep habits with 
the help of your parents. 
- You will have a fun night in a sleep clinic where we will check how well you sleep. 
This may include being connected to some machines to monitor your breathing 
and sleep.  
- X-rays (pictures of your bones from the inside) will be taken to measure your 
airways. 
- You will be randomly placed in one of two groups:  
  - In the first group, you will wear the Hyrax device, which helps your teeth and 
mouth. 
  - In the second group, you will wear the Hyrax device and another device that 
helps your tongue. 
- After a while, we will check how well you sleep again to see if there are any 
improvements. 
 
Are there any risks? 

This study is safe. However, like with any dental treatment, there could be some 
discomfort. If you ever feel uncomfortable or have any questions, you should tell 
your parent or the researchers. 
 
Do you have to be in this study?  
No, you do not have to join this study if you do not want to. It is totally your choice. 
If you decide to join, you can change your mind later and leave the study at any 
time.  
 
What will you get?   
By joining this study, you will help us learn how to make sleep better for kids like 
you.  
 
If you have any questions or if you want to talk more about this study with your 
parents or the researchers, feel free to ask! 
 
Do you agree to be part of this study? 
 
Your Name: _____________   
Your Signature: ________________   
Date: ________________   
 
Thank you! Your contribution is very valuable! 
 

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