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Variations in number and morphology of permanent teeth in 7-year-old Swedish children
1Faculty of Medicine and Odontology, Department of Odontology, Pedodontics, Umeå University, S-901 87 Umeå, Sweden. Birgitta.Backman@odont.umu.se
Objectives:
To establish the prevalence of numerical and morphological variations of permanent teeth in Swedish 7-year-olds and to accept or reject the hypothesis of a higher prevalence for these conditions in northern Sweden compared to other areas.
Design:
Cross-sectional.
Setting:
Department of Odontology/Pedodontics, Umeå University, Sweden.
Sample And Methods:
A total of 739 healthy Caucasian 7-year-olds residing in the city of Umeå, northern Sweden in 1976. The children were examined clinically and radiographically.
Results:
The prevalence of hypodontia (excluding third molars) in girls was 8.4%, in boys 6.5%, and in both sexes combined 7.4%. Of the children with hypodontia, the majority (90.9%) lacked one or two teeth. Lower second premolars were the teeth most frequently missing. The prevalence of hyperdontia was 1.9%; 11 girls and three boys were affected; 78% of the supernumerary teeth were mesiodenses. Of the morphological variations, peg-shaped upper lateral incisors were found in 0.8% of the children, double-formation (gemination) in 0.3%, taurodontism in 0.3% and dens invaginatus in 6.8%. One diagnosis was found in 18% of the children, and in almost 8% of them more than one diagnosis was found.
Conclusions:
The results agree with those obtained in similar populations and are considered representative of this ethnic group. The hypothesis of a genetically determined higher prevalence of numerical and morphological variations in the study population was not verified.