This is a random sample of 500 children (256 boys and 244 girls) from the dataset resulting from a longitudinal prospective dental study performed in Flanders (North of Belgium) in 1996 -- 2001. The cohort of 4 468 randomly sampled children who attended the first year of the basic school at the beginning of the study was annualy dental examined by one of 16 trained dentists. The original dataset consists thus of at most 6 dental observations for each child.
The dataset presented here contains mainly the information on the emergence and caries times summarized in the interval-censored observations. In addition to the interval censored observation of the emergence time of several teeth, a random visit was selected in order to create current status data of the emergence times for the same children. Also the time to caries of the four permanent first molars are included in the data set. Finally, the covariates gender, frequency of brushing, the presence of sealants and occlusal plaque on the first permanent molars collected in the first year were included as potential confounders in the data set.
For more detail on the design of the study see Vanobbergen et al. (2000).
data(tandmob)a data frame with 500 rows and the following variables
identification number of a child.
numeric gender; 0=boy, 1=girl.
factor derived from a variable GENDER.
dmft-score at baseline around the age of 7 years.
numeric occlusal plaque status of teeth 16, 26, 36, 46 (permanent first molars); 0=no plaque, 1=pits/fissures, 2=total.
factors derived from variables
OH16o, OH26o, OH36o, OH46o.
numeric brushing frequency at baseline; 0=less than daily, 1=at least once a day.
factor derived from a variable BRUSHING.
numeric baseline presence of sealing on teeth 16, 26, 36, 46 (permanent first molars); 0=no, 1=yes.
factors derived from
variables SEAL16, SEAL26, SEAL36, SEAL46.
numeric baseline dmft score of teeth 54, 64, 74, 84 (primary first molars); 0=sound, 1=caries experience.
numeric baseline dmft score of teeth 55, 65, 75, 85 (primary second molars); 0=sound, 1=caries experience.
factors
derived from variables DMF_54, DMF_64, DMF_74, DMF_84.
factors
derived from variables DMF_55, DMF_65, DMF_75, DMF_85.
left (lower) limit of observed emergence time of teeth 14, 24,
34, 44 (permanent first premolars), NA for left-censored observations.
right (upper) limit of observed emergence time of teeth 14, 24,
34, 44 (permanent first premolars), NA for right-censored observations.
left (lower) limit of observed emergence time of teeth 15, 25,
35, 45 (permanent second premolars), NA for left-censored observations.
right (upper) limit of observed emergence time of teeth 15, 25,
35, 45 (permanent second premolars), NA for right-censored observations.
left (lower) limit of observed emergence time of teeth 16, 26,
36, 46 (permanent first molars), NA for left-censored observations.
right (upper) limit of observed emergence time of teeth 16, 26,
36, 46 (permanent first molars), NA for right-censored observations.
age at visit selected to determine current status.
numeric current status of teeth 14, 24,
34, 44 (permanent first premolars) at age given by variable
CS_age; 0=not emerged, 1=emerged.
factors derived from variables
CS_14, CS_24, CS_34, CS_44.
left (lower) limit of observed time to
caries of teeth 16, 26, 36, 46 (permanent first molars), NA for left-censored observations.
right (upper) limit of observed time
to caries of teeth 16, 26, 36, 46 (permanent first molars), NA for right-censored observations.
Carvalho, J. C., Ekstrand, K. R., and Thylstrup, A. (1989). Dental plaque and caries on occlusal surfaces of first permanent molars in relation to stage of eruption. Journal of Dental Research, 68, 773--779.
Vanobbergen, J., Martens, L., Lesaffre, E., and Declerck, D. (2000). The Signal-Tandmobiel project -- a longitudinal intervention health promotion study in Flanders (Belgium): baseline and first year results. European Journal of Paediatric Dentistry, 2, 87--96.
data("tandmob", package="icensBKL")
summary(tandmob)
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