There are situations where orthodontic treatment cannot provide long-term benefits. The proposed orthotropic theory proposes that environmental factors cause malocclusion and genes decide its pattern. The primary aim of this project is to increase the success, aesthetics and permanence of the treatment result by providing the best facial change of the pediatric patients in the MP3cap period, and that myofunctional exercises can be used in addition to orthodontic treatments during the treatment process of the patients.

Many studies in recent years have emphasized the importance of the environmental factor as well as the hereditary causes of malocclusion. In particular, the activity and posture of the oral soft tissues have begun to be mentioned more. In the presence of bad habits, there are cases where orthodontic treatment alone is not sufficient and must be combined with myofunctional treatments. There are also many physicians who emphasize the importance of positioning the tongue in contact with the palate during swallowing and resting.

It is known that habits during growth and development cause malocclusions that may occur in the future. It may be possible to acquire some myofunctional exercises as a habit during the growth and development period as a prophylactic solution against malocclusions. In addition to twin block treatment, myofunctional exercises will be given to class II pediatric patients in the MP3cap period, and the effect of exercises on oral soft and hard tissues will be compared at the end of the treatment. The effects of tongue and lip movements on facial development as well as on the treatment process will be examined. Perhaps in the future, everyone can recommend doing myofunctional exercises in addition to tooth brushing.

Inclusion Criteria:

1. Having a skeletal Class II relationship (ANB > 4°),
2. Skeletal Class II relationship due to mandibular retrognathia (SNB < 78°),
3. Overjet is more than 5 mm,
4. Normal growth pattern SN-GoGn (32° ± 6°),
5. Minimum crowding of the dental arch is 4 mm or less,
6. Bilateral Class II molar and canine relationship is at least 3.5 mm,
7. Patients who are in MP3 cap period will be taken according to the Tanner-Whitehouse wrist and wrist X-ray method.

Exclusion Criteria:

1. Having received orthodontic treatment before,
2. Having severe maxillary stenosis,
3. Severe facial asymmetry according to clinical and x-ray analysis,
4. Poor oral hygiene,
5. Having mental retardation at a level that will affect the patient's cooperation,

7. Having a systemic disease that will affect the orthodontic treatment, 8. Congenital anomaly or syndrome.

Only the care provider will know which patients had only twin block treatment and which patients had both twin block and egzersize treatment. Control group will have unrevealant egzercises or no egzercises.