Dan Ericson

Reduction of cervical gaps in class II composite resin restorations

Class II cavities prepared in brass models and in extracted teeth were restored with three light-cured composite resins. A transparent cone-shaped device (Light-tip) at the end of the light source was pressed into the filling material in the proximal box for curing the resin. A second layer was filled in the recess left by the cone and cured without the cone. Controls consisted of fillings cured in two layers. In the brass cavities the contraction gap was 10 microns (+/- 10.6) with use of the cone compared with 109.5 microns (+/- 46.5) in control fillings (p less than 0.001). Extracted teeth were restored without etching of the enamel. Cervical contraction gaps in control restorations were reduced by more than half with the use of the transparent cone technique.

HLA-DR4 and number of mutans streptococci in saliva among dental students and staff

Our aim was to corroborate previous findings that HLA-DR4 carriers are characterized by higher levels of mutans streptococci in saliva than are individuals expressing other HLA-DR types. Of 68 subjects (dental students, staff, and faculty) who were sampled for salivary counts of mutants streptococci, 13 subjects with the lowest counts of mutans streptococci and 15 subjects with the highest counts were selected for HLA-typing. Of the 13 who expressed HLA-DR4, 8 were heavily colonized by mutants streptococci. Although a trend towards a relationship was found between HLA-DR4 carriage and high levels of mutans streptococci, it was not statistically significant. In this selected population, knowledge of how to minimize the risk of caries and mutans streptococci level may have influenced the results.