Tooth agenesis in down syndrome

Abstract

We studied the frequency and pattern of tooth agenesis in a Danish population with Down syndrome, trisomy 21 (46 females and 54 males). The control group consisted of a normal Danish population (2424 females and 2431 males) [Rølling, 1980: Scand J Dent Res 88:365-369; Ravn and Nielsen, 1973: Tandlaaegebladet 77:12-22]. We found that individuals with Down syndrome have an occurrence of agenesis that is some 10 times greater that in the general population with a higher frequency in males than in females. Agenesis occurred more frequently in the mandible than in the maxilla and most often on the left side. The highly significant differences were primarily found in the occurrence of agenesis of the mandibular central incisors, followed by the maxillary lateral incisors and second premolars and the mandibular second premolars. The main components in the pattern of agenesis observed in Down syndrome are supposed to be related to the peripheral nervous system and abnormal cartilagenous tissue. The present study on Down syndrome suggests that the dentition, with its many different anomalies, from agenesis to malformation, can be used as an indicator in evaluating different aspects in the patheogenetic of aneuploidy conditions.

Prevalence and patterns of permanent tooth agenesis in Down syndrome and their association with craniofacial morphology

“…Most studies report that mandibular second premolars, maxillary lateral incisors, maxillary second premolars, and mandibular central incisors are the teeth most often affected (in decreasing order). 35 In DS, the prevalence of hypodontia is much greater and more severe [12][13][14][15][16][17][18][19][20][21][22] and is recognized as a characteristic phenotypical feature of the syndrome.…”

“…38 In DS, it has been hypothesized that altered peripheral nervous system growth and abnormal development of localized chondral elements 16 may contribute as potential mechanisms responsible for the greater occurrence of dental agenesis. A recent report described that trigeminal nerve fiber growth and patterning are integrated with tooth morphogenesis, and the report hypothesized that mesenchymal dental follicles fail to form as a result of inadequate local epithelial-mesenchymal interactions due to thyroid deficiency, causing delayed proliferation of nerve cells and decreased rate of neuron production in DS.…”

“…Similarly, measurements of subjects exhibiting absence of all third molars were compared with those without this presentation. Since dental agenesis is frequently observed in both jaws in DS, [12][13][14][15][16][17][18][19][20][21][22] ANCOVA tests were additionally adjusted for the proportion of other missing teeth (vs in the regions of interest) in the total number of missing teeth. Statistical tests were conducted using SAS (version 9.1; SAS Institute Inc, Cary, NC).…”

“…2 Cephalometric analyses of subjects with DS have described platybasia, reduced maxillary and mandibular alveolar heights, short teeth, reduced maxillary and mandibular dimensions, and forward rotation of the maxillary and mandibular planes, which collectively lead to overclosure and relative mandibular prognathism. [3][4][5][6][7][8][9][10][11][12] Hypodontia in DS is well known, [12][13][14][15][16][17][18][19][20][21][22] with prevalence documented at about 90% 12,19,20 if the third molars are considered and between 30% 13 and 60% 22 when the third molars are not considered in the analysis. A very high prevalence of total agenesis of all third molars has also been described.…”

Oral Health in Individuals with Down Syndrome

“…Both Japanese (Kumasaka et al, 1997) and Brazilian studies (Acerbi et al, 2001), found 60-63% of DS individuals had one or more missing teeth. In a detailed study, Russell and Kjaer (1995) studied 100 DS individuals and compared with Danish normal population. Missing teeth had a 10 times greater frequency in DS individuals than in general population and a higher frequency in males than in females.…”