The etiology of hypodontia
is complex and yet not clearly understood, but generally it can be credited to genetic factors and environmental factor.
The interdisciplinary management of hypodontia
: background and role of paediatric dentistry.
in children with various types of clefts," The Angle Orthodontist, vol.
or even adontia in children are very rare conditions, most often associated with congenital syndromes such as Down syndrome (trisomy 21)  or ectodermal dysplasia .
Individual malocclusion traits Males Females Total % Increased overjet 192 160 352 17.51 Reverse overjet 21 15 36 1.79 Crossbite 53 39 92 4.57 Deep overbite 141 125 266 13.23 Open bite 21 20 41 2.03 Scissor bite 11 7 18 0.89 Crowding mild 30 23 53 19.75 Moderate 69 61 130 Severe 132 82 214 Hypodontia
54 26 80 3.90 Impacted teeth 72 44 116 5.77 Submerged 41 31 72 3.50 deciduous teeth Supernumerary teeth 28 34 62 3.08 Anterior spacing 89 87 176 8.75 Normal occlusion 167 135 302 15.02 Total 1121 889 2010 100 Table 4: Relationship between the IOTN (DHC) grades and study population.
A small percentage of nonsyndromic cases of hypodontia
have been linked to alterations in particular genes (Table 1), including PAX9, MSX1, and AXIN2.
Methods: A cross-sectional study was conducted to estimate the prevalence of hypodontia
in 10- to 14-year-olds from orthodontic clinics located in each of 9 regions (as determined by the government-run health insurance program, Reforma) in Puerto Rico.
This paper discusses the genetic regulation and signaling networks involved in epithelial-mesenchymal interactions during tooth development and the signaling pathway alterations that result in hypodontia
. Tooth development includes reciprocal interactions between the epithelium and mesenchyme, which is governed by the expression of sonic hedgehog (Shh), fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs), and wingless (Wnt) signaling families [Thesleff and Sharpe, 1997; Yen and Sharpe, 2008].
More recently, I have been working with orthodontists, analysing both cleft lip and palate and also congenital hypodontia
The group was able to demonstrate that mutations in the same POLR3A gene localized on chromosome 10 were responsible for three clinically different forms of leukodystrophies: Tremor-Ataxia with Central Hypomyelination (TACH) first described in Quebec cases, Leukodystrophy with Oligodontia (LO), and 4H syndrome or Hypomyelination, Hypodontia
and Hypogonadotropic Hypogonadism syndrome.
This reference work intended for specialist clinicians brings together current information and best practices in the treatment of hypodontia
. The book is divided into three sections.