Evaluation of skeletal, dental , soft tissue and condylar change in skeletal class II patients by Leone Class II Corrector

BRIEF RESUME OF THE INTENDED WORK

Need of the study:Skeletal malocclusions are caused due to abnormalities in maxilla and mandible and defects in size, shape, position or relationship between the jaws. In sagittal plane class II malocclusion may occur due to prognathic maxilla, retrognathic mandible or combination of both. Mandibular retrognathism is one of most common characteristics of skeletal class II malocclusion and has a profound unaesthetic effect on facial appearance and facial profile.In such cases, various removable and fixed appliances are used to position mandible forward by stimulating growth of mandible. Skeletal class II in growing patients with retrognathic mandible can be treated with myofunctional therapy. However, in post pubertal patients, fixed functional appliance therapy can be given.Fixed functional appliances can be grouped into rigid or flexible devices. The most commonly used rigid fixed functional appliances are the herbst and mandibular anterior repositioning appliance (MARA). However, there are certain disadvantages associated with rigid type of devices, the foremost being the patient’s inability to perform lateral side to-side mandibular movements with ease and hence, more chances of breakage due to lack of flexibility. To overcome these disadvantages, flexible devices were developed like jasper jumper, forsus , powerscope , advansync2 but they also have many disadvantages like spring wear and chances to breakage and damage.Also these are not esthetic because some protuberances appear on cheek when spring is accentuated.Forsus, most commonly used fixed functional appliance has great effects but also leads to sensitivity, soreness of the lip and cheek irritation.It may lead to development of ulcers in the buccal mucosa in some patients due to spring. However, Forsus FRD appliance reported significant distal tipping of maxillary first molars so to overcome these drawbacks. Powerscope was introduced, Dental and soft tissue changes were predominant in PowerScope patients but  Powerscope has less reliable attachment compared to other fixed functional appliances.Lower lip protusion significantly increase by use of Powerscope.To overcome the drawbacks of Powerscope,AdvanSync2 was introduced which is modification of Herbst Appliance also known as Molar to Molar appliance. EL-MoftyMHconcluded that Advansync 2 causes force dissipation to the skeletal bases through the molars only which may eventually lead to molar rotations.Kaur G Jcompared Skeletal, Dentoalveolar, and Soft Tissue changes produced by forsus and Powerscope and concluded that skeletal changes were seen significantly in both the groups, though they were more in the Forsus patients and dentoalveolar changes were predominantly seen in PowerScope patients.Jayachandran et alcompared the skeletal, dentoalveolar, and soft tissue effects of advanSync appliances with intermaxillary elastics in correction of class II malocclusion in growing patients and they concluded that the effect of class Il elastics and fixed orthodontics were similar to advanSync, with the expectation of less maxillary growth restriction and greater retrusion and retroclination of maxillary incisors.Leone class II corrector is a recent addition to an orthodontist’s armamentarium.It is available in three sizes and allows optimum patient comfort while constant and light force is delivered by MEMORIA spring which delivers force of 200g, located inside plunger which simulates mandibular advancement. In this fluidity and strength of telescopic mechanism is better and it can be anchored to direct bonding single tube,without need for a band or a round tube.Previously no studies have been conducted to demonstrate the treatment effects and clinical application of Leone class II corrector.Therefore, this study aims to evaluate skeletal, dental, soft tissue and condylar position changes produced by Leone class II corrector in skeletal class II malocclusion using CBCT.

**OBJECTIVES:**1) To evaluate the skeletal changes produced by Leone class II corrector.2) To evaluate dentoalveolar soft tissue changes using lateral cephalogram.3) To evaluate condyle position changes in class II patients using CBCT.4) To evaluate the efficacy of new armentarium that is Leone class II corrector as a fixed functional appliance.5) To evaluate the efficacy of new armamentarium that is Leone class II corrector as a fixed functional appliance.

MATERIALS AND METHODS

**Source of data:**Arandomized, prospective, cross sectional and observational study will be conducted on 20 subjects with age 11-15yrs who will come to the Department of Orthodontics and Dentofacial Orthopaedics of Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan and opt for orthodontic treatment.

**Materials:**In this study, following armamentarium will be required· CBCT scans· Lateral cephalograms· Leone Class II Corrector

Method of Collection of dataCase records including lateral cephalogram and CBCT of patients will be taken for each patient before placing Leone class II corrector and after removal of Leone class II corrector

Prefunctional(T0) and postfunctional(T1) images will be taken with the patients sitting in an upright position with the Frankfort horizontal plane parallel to the ground. They will be instructed to breathe normally through the nose and to avoid swallowing during the scanning process. CBCT datasets will be acquired by software with reconstruction slice thickness of 0.300 mm and 728 X 728 matrix. A single 270-degree rotation 20-second-high resolution scan will be made with isotropic voxel size set at 0.300mm and 14 X 19 cm field of view.The raw images will be exported into Digital Imaging and Communications in Medicine (DICOM). The field of view will be confined to the right and left TMJ.. This is  done so that condylar head, glenoid fossa and external auditory meatus will be visualized.Data will be analyzed by using SPSS software version 26.0, IBM, Chicago, USA .

Technique to measure forward shift of condyleAfter orientation standardization of axial section will be done of condyle with maximum thickness. This will be opened in sagittal section and atuberculo-meatal line will be drawn, a perpendicular to tubo-mental line passing tangentially to posterior surface of glenoid fossa will be made and then a perpendicular distance from this tangent will be measured horizontally to the most superior point of condyle(Fig-1).

Technique to measure downward shift of condyleAfter orientation standardization of axial section will be done of condyle with maximum thickness. This will be opened in segittal section and atuberculo-meatal line will be drawn, a perpendicular to tubo-mental line passing tangentially to posterior surface of glenoid fossa will be made and then a perpendicular distance from this tangent will be measured horizontally to the most superior point of condyle. The distance will measured vertically from most superior point of condyle to most superior point of glenoid fossa.

Patients who fulfill the selection criteria will be included, the inclusion criteria is:l Skeletal class II relationship with ANB>50.l Retrognathic mandible with SNB<770.l Age group:  Post-pubertal patients between the age group of 11 and 16 years.l Average to horizontal growth pattern.l Overjet greater than 5 mm.l Positive pre-treatment visual treatment objective.l CVMI stage 4,5,6.lNo evidence of periodontal or gingival problems at the beginning of orthodontic treatment.

Exclusion criteria

l Patients with neuromuscular joint disorder.

l Patients  with previous orthodontic treatment.

l Patients  with a history or symptoms of temporomandibular joint disease.

l Patients with skeletal open bite.

l Severe proclination and crowding of anterior teeth.

l Patients with compromised peridontium.

MethodThe selected pretreatment lateral cephalograms will be traced manually on an acetate paper with 0.5mm lead pencil. Cephalometric measurements that will be used in study are-

Maxillary Skeletal Parameters:

ANS-PNS

SNA

N-ANS

N-PNS

Mandibular Skeletal Parameters:

SNB

SN-GoGn

Saddle angle

Articular angle

Co-Gn

Ar-Go

Go-Pg

B-Pg

 l Maxillo-Mandibular Parameters:

ANB

N-A-Pg

Wits Appraisal

l Dentoalveolar Parameters(Fig-4):

U1-NA[angular measurement]

U1-NA[linear measurement]

L1-NB[angular measurement]

L1-NB[linear measurement]

IMPA

Overjet

L6-Ptv

U6-Ptv

Interincisal angle

l Soft Tissue Parameters:

Pog-Pog’

Nasomental angle

Upper Lip Prominence

Lower Lip Prominence

Nose Prominence

Chin Prominence

E-line:

Upper lip

Lower lip

Z-Angle

H-Angle