Comparison Between Protraction Facemask and Upper Braces for Underbite Correction in Growing Children

The goal of this clinical trial is to compare the effectiveness of a protraction facemask and upper partial fixed appliance in correcting anterior crossbite in growing children with class III malocclusion. It will also learn about the patients perceptions of these treatments. The main questions it aims to answer are:

i. What is the rate of success in achieving anterior crossbite correction with the protraction facemask and upper partial fixed appliance? ii. Are there any significant differences in the dental, skeletal and soft tissue outcomes between the two treatment groups? iii. What are the patient's perceptions associated with each treatment modality received.

iv. What is the incidence of adverse effects or complications and breakages associated with each treatment modality?

Participants will be randomly assigned to one of two groups: 1) protraction facemask; or 2) upper partial fixed appliance. After investigators decide which group participants will be in, investigators will take some standard records for the study before starting the treatment. These records include:

1. Making moulds of their teeth to create study models 2. Taking a side-view X-ray of their head (called a lateral cephalometric radiograph)

Additionally, the participant will need to fill out a quick 5-minute survey called the Child Perceptions Questionnaire 8-10 (CPQ8-10). It has 25 short questions. The participant will do this survey at four different times: 1) before starting the treatment; 2) 3 months into the treatment; 3) 6 months into the treatment; and 4) after the treatment is done.

Investigators will set up appointments for the treatment based on the type assigned. Once the treatment starts, investigators will see the participant every six weeks until it is finished.

If the participant gets a protraction facemask, investigators will put a fixed expander appliance in the mouth at the palate. Investigators will teach them how to activate the appliance once a day for seven days. Afterwards, the participant will use the protraction facemask with elastics connecting the appliance in the mouth and the protraction facemask. The participant must wear it for 14 hours a day, at night.

If the participants gets an upper fixed partial appliance, investigators will bond upper fixed appliances in the mouth.

Investigators will teach the child how to clean the appliance and their mouth to avoid any potential problems or side effects during the treatment.