Bad habits
For example, licking teeth during teething can lead to anterior protrusion of upper and lower front teeth (buck teeth); finger-sucking and biting the lower lip can lead to a tendency of lip-tilting buck teeth of upper front teeth. Prolonged mouth breathing can cause the lip muscles to relax and the lower jaw to recede, forming maxillary buck teeth.
Local disorders during the teething period
The congenital loss of the lower front teeth during the period of teething or the premature loss of the mandibular milk molars for various reasons can lead to the underdevelopment of the anterior segment of the mandibular arch or the reduction of the length of the lower arch, and the relative anterior protrusion of the upper front teeth or the upper arch; the abnormal order of eruption of the maxillary anterior multiple teeth and permanent molars during the period of teething can also lead to the bucking of the upper front teeth.
Trauma
Trauma to the mandible or chin during growth and development can lead to delayed development of the mandible or temporomandibular joint, resulting in bony mandibular recession, which can also manifest as maxillary buck teeth.
Giant tongue syndrome
Due to the oversized tongue and strong tongue muscle, the upper and lower dental arches are overdeveloped and the upper and lower teeth protrude forward sagittally, which manifests as buck teeth.