Orthodontic Appliances

The developed deciduous occlusion provides a good prediction for how the occlusions will develop in the future:

• A distal step of 1 mm or more invariably leads to a Class II molar relationship in the permanent dentition ^[1-5].
• A flush terminal plane leads to Class II in about 40% of patients ^[3-4]. A flush terminal plane combined with a Class II canine relationship seems to indicate a higher risk of distal occlusion ^[6]
• Lingually inclined upper deciduous incisors that are covered by the lower lip are likely to develop into  Class II, div 2 in the permanent dentition ^[7]
• If there are signs of convexity and a retruded mandible in the fully developed deciduous dentition, development of Class II div 1 can be expected. ^{[Bishara 1997]}
• Class II occlusal relations (distal step, Class II deciduous canine relationship, excessive overjet) in the deciduous dentition) persist into the mixed dentition. ^{[Baccetti 1997]}
• Lack of adequate space in the deciduous dentition is a reliable indicator of treatment need ^[7-9]:

 Table adapted from  McNamara JA Jr, Brudon WL. Orthodontics and dentofacial orthopedics. Chapter 3: Dentitional development, Ann Arbor (Mich): Needham Press; 2001.

Malocclusions tend to become more severe as the dentition develops:

• Incidence of mandibular incisor crowding increases from 14% at the age of 6 years to 51% at 14 years of age ^[10].
• Overbite and overjet typically increase by 1-2 mm when the permanent incisors erupt ^{[7, 8, 11-14]}. Later on they tend to decrease less than 1 mm ^{[11, 14]}.
• Incisor crowding or malalignment that is present when all permanent incisors have erupted, will probably remain or become more severe by the time all permanent teeth have erupted. ^{[5, 15]}
• If Class II div 1 is present at age 6, mandibular growth deficiency occurs between age 6 and 15. ^[Buschang]

An additional benefit is that overjet-related risk of incisor trauma may be reduced, if treatment is started before the permanent maxillary incisors have erupted. ^{[Koroluk, Turpin]} Untreated excess overjet may increase the risk of incisor trauma by up to 400%. ^{[Norton, Schatz, Harrison]}

The AAO recommends that every child undergoes an orthodontic check-up before the age of seven years. ^[VV] Early treatment may prevent more serious problems from developing and may make treatment at a later age shorter and less complicated. In some cases, early treatment can lead to results that may not be achievable after the face and jaws have finished growing. ^[WW]

According to the AAPD, “Guidance of eruption and development of the primary, mixed, and permanent dentitions is an integral component of comprehensive oral health care for all pediatric dental patients. … Early diagnosis and successful treatment of developing malocclusions can have both short-term and long-term benefits while achieving the goals of occlusal harmony and function and dentofacial esthetics.” ^[XX]

Juvenile Growth Spurt

In addition to the well-known pubertal growth spurt, the juvenile growth spurt provides another excellent opportunity to benefit from natural mandibular growth. Read more

References