Tooth number abnormality: from bench to bedside

Abstract

Tooth number abnormality is one of the most common dental developmental diseases, which includes both tooth agenesis and supernumerary teeth. Tooth development is regulated by numerous developmental signals, such as the well-known Wnt, BMP, FGF, Shh and Eda pathways, which mediate the ongoing complex interactions between epithelium and mesenchyme. Abnormal expression of these crutial signalling during this process may eventually lead to the development of anomalies in tooth number; however, the underlying mechanisms remain elusive. In this review, we summarized the major process of tooth development, the latest progress of mechanism studies and newly reported clinical investigations of tooth number abnormality. In addition, potential treatment approaches for tooth number abnormality based on developmental biology are also discussed. This review not only provides a reference for the diagnosis and treatment of tooth number abnormality in clinical practice but also facilitates the translation of basic research to the clinical application.

Congenital Tooth Agenesis and Risk of Early-Onset Cancer

“…Tooth agenesis was defined as missing 1 or more teeth from birth, excluding third molars. No differentiation among phenotypes was made because the correlation between agenesis of deciduous teeth (rare) and the permanent dentition (common) is very high, and number of missing teeth in heritable tooth agenesis can vary considerably even within families . Data on tooth agenesis were obtained from 2 different national registries.…”

“…3,4 Several causative genes have also been identified for isolated (nonsyndromic) tooth agenesis, which can present with variable phenotypes, even within families. 3,5 Variants in some genes, such as WNT10A (OMIM 150400) and EDA (OMIM 300451), can present as both syndromic and nonsyndromic tooth agenesis. 4 Previous reports have suggested that individuals with tooth agenesis may have an increased risk of developing certain cancer types, as some of the cellular signaling pathways important for tooth formation also play a role in cancer development.…”

“…Congenital absence of 1 or more teeth (tooth agenesis) is common, with an estimated prevalence of 7.8% in Danish school children . In rare cases, tooth agenesis presents as part of a syndrome (syndromic tooth agenesis); it is a cardinal feature of ectodermal dysplasia and a possible feature of Down syndrome, Sotos syndrome, tuberous sclerosis complex, and other genetic syndromes . Several causative genes have also been identified for isolated (nonsyndromic) tooth agenesis, which can present with variable phenotypes, even within families .…”

Insilco analysis of an interaction between an endogenous peptide fragment of NUR77 receptor from human cells and USAG1 protein - may induce teeth regeneration

“…USAG-1(uterine sensitization associated gene-1), expressed predominantly in the kidneys, inhibits BMP-7's bioactivity which is crucial for tooth development. [6][7][8][9][10][11][12] By way of knocking out the gene Usag-1, tooth regeneration has been shown. Hence, inhibition of Usag-1 may provide a way for teeth regeneration.…”

Spatial and Temporal Expression of Ectodysplasin-A Signaling Pathway Members During Mandibular Condylar Development in Postnatal Mice

“…7 Previous studies have focused on the regulatory role of EDA in epithelial development including that of teeth and hair. 8,9 It should be noted that in ectodermal dysplasia there are disorders of epithelial-mesenchymal interactions affecting the structure of the endoderm and ectoderm, which are not confined to a single ectoderm. 10 The mandibular morphology was abnormal in EDA −/− mice (Tabby mice, a mouse model of XLHED), which showed the lower corpus of the jaw, narrower neck of the condyle, and marked backward projection of the coronoid process.…”