Heredity, genetics and orthodontics: How much has this research really helped?

Abstract

Uncovering the genetic factors that correlate with a clinical deviation of previously unknown etiology helps to diminish the unknown variation influencing the phenotype. Clinical studies, particularly those that consider the effects of an appliance or treatment regimen on growth, need to be a part of these types of genetic investigations in the future. While the day-to-day utilization of “testing” for genetic factors is not ready for practice yet, genetic testing for monogenic traits such as Primary Failure of Eruption (PFE) and Class III malocclusion is showing more promise as knowledge and technology advances. Although the heterogeneous complexity of such things as facial and dental development, the physiology of tooth movement, and the occurrence of External Apical Root Resorption (EARR) make their precise prediction untenable, investigations into the genetic factors that influence different phenotypes, and how these factors may relate to or impact environmental factors (including orthodontic treatment) are becoming better understood. The most important “genetic test” the practitioner can do today is to gather the patient’s individual and family history. This would greatly benefit the patient, and augment the usefulness of these families in future clinical research in which clinical findings, environmental, and genetic factors can be studied.

Genetics of Dentofacial and Orthodontic Abnormalities

“…The genetic factors appear to be heterogeneous with monogenic influence (usually autosomal dominant with incomplete penetrance and variable expressivity) in some families and multifactorial (polygenic complex) influence in others. 6 …”

Genetic And Environmental Factors Involved In The Development Of Oral Malformations Such As Cleft Lip/Palate In Non-Syndromic Patients And Open Bite Malocclusion

“…In addition, there are also skeletal muscle proteins such as α-actin-2 and α-actin-3 (fast twitch fiber or type II). Studies have shown that an increased vertical dimension is inversely related to type II muscle fibers, that is, anterior open bite or increased vertical dimension is associated with type I muscle fibers (of slow contraction) that can be found in the masseter muscle [82].…”

“…Reference [82] observed a significant difference in the growth of the mandible in the sagittal plane, when they compared groups of Caucasian men with a genetic variation in the CYP19A1 gene with groups of women who inherited the same genetic variation. It was observed that the group of men showed more significant differences in facial growth than the group of women, suggesting that the variant of the CYP19A1 gene may be a multiethnic marker for the sagittal growth of the male mandible.…”

“…Reference [82] also showed that individuals with polymorphisms (Pro561Thr) in the growth hormone receptor (GHR) coding gene, had differences in the length of the mandibular branch (condyle-gonium) and variation in skeletal growth. This study showed that the group that presented this polymorphism had a significantly shorter mandibular branch length than the group that did not have this allelic variation.…”

Levantamento epidemiológico de fatores relacionados com a má oclusão em crianças de 3 a 9 anos de idade no Equador

“…Hartsfield et al (2017), relata que os fatores genéticos determinam os diferentes fenótipos, mas que esses fatores se relacionam ou impactam com os fatores ambientais, incluindo o tratamento ortodôntico. O mais importante "teste genético" que o praticante pode fazer hoje é reunir a história individual e familiar do paciente.…”