Cephalometric Evaluation of a Clear Mandibular Advancement Appliance Based on the Twin-block Design

This study evaluates the cephalometric effects of a clear mandibular advancement appliance for the treatment of skeletal class II growing patients suffering from mandibular deficiency.

Study Overview

• Status: Completed
• Conditions: Skeletal Malocclusion
• Intervention / Treatment: Device: Clear Mandibular Advancement Appliance

Detailed Description

A Clear mandibular advancement appliance is constructed comprised of a clear dental splint of 1.5 mm thickness adapted on the patient's teeth. This is followed by the construction of acrylic bite ramps bonded over the splints. The bite ramps are constructed as such when the patient bites into occlusion, he/she has to advance the mandible to bring the two parts of the appliance together. Lateral cephalometric radiographs were obtained pre and post-treatment to evaluate the effects on the patient's maxilla, mandible and dentition.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 8 years to 12 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

1. Gender: Female subjects.
2. Chronological age: All recruited subjects were between the ages of 8-12 years.
3. Anteroposterior skeletal relationship: Subjects with skeletal Class II malocclusion with normal maxilla and retrognathic mandible were selected. This was confirmed using lateral cephalometric radiographic analysis with the following parameters: decreased effective mandibular length (Co-Gn) according to McNamara composite , SNB<78, SNA=82+2.

4. Dental characteristics:

   • Angle Class II molar relationship ranging from edge to edge to full unit Class II.
   • Overjet ranging between 5-10 mm.
   • Absence of posterior crossbite and/or tendency for posterior crossbite.
5. Skeletal maturation stage: The growth stage for all subjects was selected to be before or at the prepubertal growth spurt. This was confirmed by cervical vertebral maturation analysis from the lateral cephalometric radiograph. The cervical vertebrae maturation stage required was Cervical Vertebrae Maturation stage 2-3 according to the cervical vertebrae maturation index by Baccetti et al. allowing sufficient time before the end of the growth spurt.
6. No previous history of orthodontic treatment.
7. Absence of systemic diseases affecting growth or craniofacial development. -

Exclusion Criteria:

-

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Treatment arm; Subjects receiving the clear mandibular advancement appliance	Device: Clear Mandibular Advancement Appliance; Clear Mandibular Advancement Appliance for treatment of skeletal class II patients with retrognathic mandible

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Effective Mandibular Length	Condylion-Gnathion	12 months
Mandible to cranial base	Sella-Nasion-B point	12 months
Effective maxillary length	Condylion-A point	12 months
Maxilla to cranial base	Sella-Nasion-A point	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lower incisor inclination	Lower incisor to mandibular plane	12 months
Lower incisor AP position	Lower incisor Anteroposterior position	12 months
Upper incisor inclination	Upper incisor to palatal plane	12 months
Upper incisor AP position	Upper incisor Anteroposterior position	12 months
Profile convexity	N'Sn/Sn-Pog'	12 months
Lip protrusion	Ls-E plane	12 months
Chin position	Soft tissue Pogonion position	12 months

Collaborators and Investigators

• Sponsor: Ain Shams University

Publications and helpful links

General Publications

• Tulloch JF, Phillips C, Koch G, Proffit WR. The effect of early intervention on skeletal pattern in Class II malocclusion: a randomized clinical trial. Am J Orthod Dentofacial Orthop. 1997 Apr;111(4):391-400. doi: 10.1016/s0889-5406(97)80021-2.
• Baccetti T, Franchi L, Toth LR, McNamara JA Jr. Treatment timing for Twin-block therapy. Am J Orthod Dentofacial Orthop. 2000 Aug;118(2):159-70. doi: 10.1067/mod.2000.105571.
• Clark WJ. The twin block technique. A functional orthopedic appliance system. Am J Orthod Dentofacial Orthop. 1988 Jan;93(1):1-18. doi: 10.1016/0889-5406(88)90188-6. No abstract available.
• O'Brien K, Wright J, Conboy F, Sanjie Y, Mandall N, Chadwick S, Connolly I, Cook P, Birnie D, Hammond M, Harradine N, Lewis D, McDade C, Mitchell L, Murray A, O'Neill J, Read M, Robinson S, Roberts-Harry D, Sandler J, Shaw I. Effectiveness of treatment for Class II malocclusion with the Herbst or twin-block appliances: a randomized, controlled trial. Am J Orthod Dentofacial Orthop. 2003 Aug;124(2):128-37. doi: 10.1016/s0889-5406(03)00345-7.
• Jena AK, Duggal R, Parkash H. Skeletal and dentoalveolar effects of Twin-block and bionator appliances in the treatment of Class II malocclusion: a comparative study. Am J Orthod Dentofacial Orthop. 2006 Nov;130(5):594-602. doi: 10.1016/j.ajodo.2005.02.025.
• Teuscher U. A growth-related concept for skeletal class II treatment. Am J Orthod. 1978 Sep;74(3):258-75. doi: 10.1016/0002-9416(78)90202-6.
• Lv Y, Yan B, Wang L. Two-phase treatment of skeletal class II malocclusion with the combination of the twin-block appliance and high-pull headgear. Am J Orthod Dentofacial Orthop. 2012 Aug;142(2):246-55. doi: 10.1016/j.ajodo.2010.12.024.
• O'Brien K, Macfarlane T, Wright J, Conboy F, Appelbe P, Birnie D, Chadwick S, Connolly I, Hammond M, Harradine N, Lewis D, Littlewood S, McDade C, Mitchell L, Murray A, O'Neill J, Sandler J, Read M, Robinson S, Shaw I, Turbill E. Early treatment for Class II malocclusion and perceived improvements in facial profile. Am J Orthod Dentofacial Orthop. 2009 May;135(5):580-5. doi: 10.1016/j.ajodo.2008.02.020.
• Cozza P, Baccetti T, Franchi L, De Toffol L, McNamara JA Jr. Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review. Am J Orthod Dentofacial Orthop. 2006 May;129(5):599.e1-12; discussion e1-6. doi: 10.1016/j.ajodo.2005.11.010.
• Toth LR, McNamara JA Jr. Treatment effects produced by the twin-block appliance and the FR-2 appliance of Frankel compared with an untreated Class II sample. Am J Orthod Dentofacial Orthop. 1999 Dec;116(6):597-609. doi: 10.1016/s0889-5406(99)70193-9.
• Trenouth MJ. Cephalometric evaluation of the Twin-block appliance in the treatment of Class II Division 1 malocclusion with matched normative growth data. Am J Orthod Dentofacial Orthop. 2000 Jan;117(1):54-9. doi: 10.1016/s0889-5406(00)70248-4.
• Mills CM, McCulloch KJ. Posttreatment changes after successful correction of Class II malocclusions with the twin block appliance. Am J Orthod Dentofacial Orthop. 2000 Jul;118(1):24-33. doi: 10.1067/mod.2000.104902.
• Singh GD, Hodge MR. Bimaxillary morphometry of patients with class II division 1 malocclusion treated with twin block appliances. Angle Orthod. 2002 Oct;72(5):402-9. doi: 10.1043/0003-3219(2002)0722.0.CO;2.
• Schaefer AT, McNamara JA Jr, Franchi L, Baccetti T. A cephalometric comparison of treatment with the Twin-block and stainless steel crown Herbst appliances followed by fixed appliance therapy. Am J Orthod Dentofacial Orthop. 2004 Jul;126(1):7-15. doi: 10.1016/j.ajodo.2003.06.017.
• Flores-Mir C, Major PW. Cephalometric facial soft tissue changes with the twin block appliance in Class II division 1 malocclusion patients. A systematic review. Angle Orthod. 2006 Sep;76(5):876-81. doi: 10.1043/0003-3219(2006)076[0876:CFSTCW]2.0.CO;2.
• Khoja A, Fida M, Shaikh A. Cephalometric evaluation of the effects of the Twin Block appliance in subjects with Class II, Division 1 malocclusion amongst different cervical vertebral maturation stages. Dental Press J Orthod. 2016 Jun;21(3):73-84. doi: 10.1590/2177-6709.21.3.073-084.oar.
• Mills CM, McCulloch KJ. Treatment effects of the twin block appliance: a cephalometric study. Am J Orthod Dentofacial Orthop. 1998 Jul;114(1):15-24. doi: 10.1016/s0889-5406(98)70232-x.

Study record dates

Study Major Dates

• Study Start (Actual): September 20, 2016
• Primary Completion (Actual): December 15, 2017
• Study Completion (Actual): March 4, 2018

Study Registration Dates

• First Submitted: January 29, 2019
• First Submitted That Met QC Criteria: January 29, 2019
• First Posted (Actual): January 31, 2019

Study Record Updates

• Last Update Posted (Actual): January 31, 2019
• Last Update Submitted That Met QC Criteria: January 29, 2019
• Last Verified: January 1, 2019

More Information

Terms related to this study

• Keywords: twin-block; Aligner; Functional appliance; skeletal class II; mandibular deficiency; Growing patients; Clear appliance
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Malocclusion
• Other Study ID Numbers: AinShamsUOrthodontics

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No