Skeletal and Dental Changes with Hyrax-type Rapid Maxillary Expander Anchored to Permanent Versus Deciduous Molars (DENTHYRAX)

Comparison of Skeletal and Dental Changes with Hyrax-type Rapid Maxillary Expander Anchored to Permanent (6) Versus Deciduous Molars (V) in Growing Subjects

The aim of the study is to compare the skeletal and dental maxillary expansion obtained with an Hyrax tooth-borne expander anchored either on the 2nd deciduous molars (V) or on the 1st permanent molars (6)

Study Overview

• Status: Completed
• Conditions: Maxillary Hypoplasia
• Intervention / Treatment: Device: Experimental group; Device: Control group

Detailed Description

The aim of the study is to compare the skeletal and dental maxillary expansion obtained with an Hyrax tooth-borne expander anchored either on the 2nd deciduous molars (V) or on the 1st permanent molars (6).

The main objective is to compare at the skeletal level the distance between the cephalometric points, right jugal (RJ) and left jugal (JR) (maxillary base).

The secondaries objectives are performed at the dental level by measuring the distance between the maxillary first molars mesio-palatal cusp and the cuspids cups. Molar derotation is also assessed

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Montpellier, France, 34090
    • Centre de Soins Dentaires

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 6 years to 12 years (Child)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patient coming to the dental clinic for a first orthodontic consultation in mixed dentition
• Patient aged 6 to 12 years
• Patient with a transverse maxillary deficiency requiring rapid maxillary expansion
• Presence of 1st permanent molars "6" and 2nd deciduous "V" molars with sufficient root length

Exclusion Criteria:

• Syndromic patients (all syndromes combined: cleft lip, etc.)
• Patient with V or 6 with decays (or with major root resorption)
• Patient with oral hygiene non compatible with orthodontic treatment
• Failure to obtain informed written consent
• No affiliation to a French national medical health system
• Patient with a legal protection measure

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group; Hyrax-type rapid maxillary expander anchored on the 2nd deciduous molars (V)	Device: Experimental group; The experimental group will have a hyrax rapid maxillary expander anchored on the 2nd deciduous molars (V)
Active Comparator: Control group; Hyrax-type rapid maxillary expander anchored on the 1st permanent molars (6)	Device: Control group; The control group will have a hyrax rapid maxillary expander anchored on the 1st permanent molars (6)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in skeletal maxillary width before/ after rapid maxillary expansion	Difference in skeletal maxillary width measured on frontal cephs (distance between the cephalometric points "right jugal RJ" and "left jugal JR" of the Ricketts analysis) before (V0)/after (V8) rapid maxillary expansion with tooth-borne expander type Hyrax	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference of the inter-molar distance before/after	Difference before (V0) / after (V8) rapid maxillary expansion with tooth-borne expander type Hyrax of the inter-molar distance (mesiopalatal cusp) assessed on dental casts	6 months
Difference of the inter-canine distance before/after	Difference before (V0) / after (V8) rapid maxillary expansion with tooth-borne expander type Hyrax of the inter-canine distance (cuspids cusp) assessed on dental casts	6 months
Difference in the amount of molar derotation (inter-molar angle) before/after	Difference before (V0) / after (V8) rapid maxillary expansion with tooth-borne expander type Hyrax in the amount of molar derotation (inter-molar angle) assessed on dental casts	6 months
Inter-operator reproducibility	Inter-operator reproducibility assessed by the intra-class correlation coefficient	1 month

Collaborators and Investigators

• Sponsor: University Hospital, Montpellier

Study record dates

Study Major Dates

• Study Start (Actual): May 22, 2023
• Primary Completion (Actual): December 20, 2024
• Study Completion (Actual): January 15, 2025

Study Registration Dates

• First Submitted: March 6, 2023
• First Submitted That Met QC Criteria: March 6, 2023
• First Posted (Actual): March 17, 2023

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 15, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Child; Palatal expansion technique; Rapid maxillary expansion; Orthodontic appliances; Orthodontic interceptive; Dentition mixed; Tooth deciduous
• Other Study ID Numbers: RECHMPL22_0144

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No