Proportional Microdontia Of Permanent Teeth In Down's Syndrome Individuals
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One can imagine that such an award ceremony would be quite solemn, but as often happens in life, this time things did not go strictly according to plan. There was a humorous moment during the ceremony, in which the wrong hat was gwen to Dr Nair and when he placed it on his head, it was too large. The hat sank down to his eyes Professor Anna-Kann Holm, the Dean of the University of Ume3. found her hat to be too small They quickly realised that the assistant had given them the wrong hats. The photograph shows the hats being swapped and then fitted correctly.
ASE members will remember that Dr Nair generously presented a lecture to the Victorian Branch on September 23, 1992 (Aust
hdod Nan 1992. 18(2) 7) during a visit to Australia At that lecture he presented his findings and his thoughts on the roles of epithelium. fungi, residual bactena and foreign bodies in the maintenance of asymptomatic penapical pathology More recently he has contributed to a new endodontic textbook Essential hdodontology. which I recently reviewed (Aust Endodl 1998. 24 138)
This journal will continue to follow Dr Nair's work. Watch this space'
Peter Parashos and David Figdor
From The Journals Root Canal Anatomy Of Down's Syndrome Teeth
Kelsen A.E.. ffieser /.A,. love R.M. IADR Abstracts, ANZ Dwision. Brisbane 1998; p29. abs C5.
Numerous studies have investigated the root canal morphology of a normal population. however, no information is available on canal morphology of people with Down's Syndrome (DS). The aim of this study was to identify any anatomical differences in root canal structure of teeth from DS patients which may help in future endodontic treatment planning and canal instrumentation for these individuals. A total of 28 I fully-formed anterior and premolar teeth from 66 DS individuals were examined. The majority of teeth came from 8 - 20 year-olds. The teeth were inspected for anatomical irregularities and the crown and root length were measured from the mid-labial point of the cemento-enamel junction using a digital micrometer. Teeth were then decoronated. pulpal tissues removed
by papain ( I %) treatment, Indian ink injected into the root canal and then centrifuged. The teeth were decalcified (10% nitric acid), dehydrated and rendered transparent in cedar oil. The root canal morphology was examined using a stereomicroscope. The findings were then compared to reported data using Student's t tests.
The results indicated that the crown and root length of anterior and premolar teeth were significantly shorter than values from a normal population and that the root canals in these teeth were generally single with a decreased incidence of lateral canals compared to a normal population. Canal irregularities such as apical deltas were rare. These observations are commensurate with the suggestion that Trisomy 2 I exerts its effect by slowing the mitotic cycle and rate of cell proliferation resulting in generalised retardation of growth.
Proportional Microdontia Of Permanent Teeth In Down's Syndrome Individuals Bell E.. Townsend G.. ffieser /.. Wilson D. IADR Abstracts, ANZ Diviuon. Brisbane 1998; p29. obs C3.
Although the triplicate dose of chromosome 21 in Down's Syndrome is known to affect most tissues. the pathogenesis of organ anomalies remains unresolved. Analysis of tooth size may enable retrospective inference of odontogenesis in such individuals. This pilot study aimed to quantitatively compare dentine and enamel from Down's Syndrome individuals and controls to determine factors contributing to microdontic permanent crowns in Trisomy 2 I individuals. Sample groups comprised extracted permanent upper lateral incisors from 16 Down's Syndrome patients and I7 normal individuals. Mesiodistal and labiolingual tooth crown dimensions were initally measured. Crowns were subsequently hemisectioned midsagitally and photographed using a stereomicroscope. Standardised photographic measurements of cervical labiohgual dentine/pulp thickness. crown height of dentine. and labial and lingual enamel thicknesses were recorded.
Downs Syndrome crowns were significantly smaller than controls mesiodistally ( 17.2% 2 SE 7.7%) labiolingually (20.4% 5 SE 5.7%). Labiolingual dentine/pulp width (20.5% ? SE 7%) and dentine height (24.7% 2 SE 10%). were also significantly smaller in Down's Syndrome individuals than controls. However, ratios of mesiodistal:labiolingual crown diameter and height:width of dentine were not significantly different. Enamel in Down's Syndrome individuals was significantly thinner than controls. However, after removing tooth size influence by calculating enamel thickness:total dentine/pulp thickness, only cervical enamel was significantly thinner in Down's Syndrome patients. It is concluded that permanent upper lateral incisor crowns from Down's Syndrome individuals are significantly smaller than those of normal individuals. While both enamel and dentine in Down's Syndrome teeth are significantly thinner, these dimensions are proportional to those of normal teeth. except cervically. Findings suggest that growth retardation is more pronounced in later developing tooth crown regions.
PAGE 28 AUSTRALW ENDODONTIC JOURNAL VOLUME 25 No I APRIL 1999