Prevalence of dental erosion in children: a national survey.

OBJECTIVES: To measure the prevalence of dental erosion in permanent teeth in Iceland as part of the National Oral Health Survey. METHODS: A representative, nationwide sample of 2251 Icelandic children, 20% of those aged 6, 12 and 15 year, was examined. Dental erosion was recorded for all erupted permanent teeth and graded using the modified scale of Lussi. RESULTS: Erosion was not seen in the permanent teeth of six-year-olds, but was present in 15.7% of 12-year-olds, more frequently in boys than girls (19.9% boys, 11.0% girls; P < 0.001). Among 15-year-olds, dental erosion was seen among 30.7% of subjects (38.3% boys, 22.7% girls; P < 0.001). Severity of erosion was mostly scored as grade I, with only 5.5% of 15-year-olds scored as grade II, mostly on tooth 46 (4.3%) and 36 (4.2%). For 12-year-olds, 0.9% had erosion scores of grade II mostly on tooth 46 (0.8%) and 36 (0.7%). No subjects had erosion of grade III. The most common clinical manifestation of erosion was the appearance of cup-like lesions on the cusps of lower first molars. CONCLUSIONS: Dental erosion was frequently present by the age of 12; the prevalence doubled by age 15 and was seen almost twice as often among boys than girls. Teeth most frequently showing signs of erosion were the lower first molars. The rapidly growing prevalence of erosion demonstrated by this nationwide survey emphasizes the need for further research into the aetiology of erosion and possible methods of preventing and treating this emerging dental problem.

Construction and characterization of an infectious molecular clone of maedi-visna virus that expresses green fluorescent protein.

The construction of a molecular clone of maedi-visna virus (MVV) expressing the enhanced green fluorescent protein (EGFP) is described. The egfp gene was inserted into the gene for dUTPase since it has been shown that dUTPase is dispensable for MVV replication both in vitro and in vivo. MVV-egfp is infectious and EGFP expression is stable over at least six passages. This fluorescent virus will be a useful tool for monitoring MVV infections.

Caries prevalence of permanent teeth: a national survey of children in Iceland using ICDAS.

OBJECTIVES: The Icelandic Oral Health Survey aimed to obtain new national data on the oral health of Icelandic children and teenagers. METHODS: A representative stratified random cluster sample of 2251 Icelandic children in first, seventh and 10th grade, aged approximately 6-, 12- and 15-years old was examined for caries prevalence using the ICDAS criteria. Bite-wing digital radiographs were obtained for the children in 7th and 10th grade. RESULTS: D(3)MFT scores by visual examination of 6-, 12- and 15-year olds were 0.12, 1.43 and 2.78 respectively but when including radiographs, the D(3)MFT rose to 2.11 at 12 years and 4.25 at 15 years. The Significant Caries Index, SiC, by visual examination for 12 and 15 y was 3.7 and 6.7 respectively but was 4.7 for 12 y and 8.9 for 15 y with radiographs. In all age groups and at most disease levels, caries was active in the majority of the lesions (58-100%). The percentage of children with no visually detectable caries at D(3)/D(1) level was 93%/74% for 6 years, 48%/22% for 12 years and 35%/16% for 15 years. When radiographs were included the percentage reduced to 34%/15% for 12 years and 20%/6% for 15 years. Approximately 80% of 12- and 15-year-olds had at least one of their first molars sealed, with the mean number of sealed first molars being 2.2 among 12 y and 2.0 among 15 y. CONCLUSIONS: Caries levels were higher than expected in this national survey and further away from the goals of the National Health Plan for 2010 than anticipated. Caries distribution was skewed with more than half of the children having low caries scores but a wide distribution of caries experience was seen among the remaining population.