Shrinkage stresses associated with incremental composite filling techniques in conservative Class II restorations

Conservative Class II preparations are widely utilized, however the stresses produced by incremental composite placement/curing has not been demonstrated. The purpose of this investigation was to visualize the stresses generated by composite resin placed into photoelastic models of conservative Class II preparations using different incremental techniques. Conservative Class II preparations on three different primary molar replicas were cast life-sized in a photoelastic material. Incremental placement/curing techniques used were oblique, gingival-occlusal, and facial-lingual and were compared with bulk placement/curing. The photoelastic stresses produced with conservative Class II restorations were of lower intensity than conventional Class II and larger composite restorations previously reported. Few differences in shrinkage-induced stresses were observed between the incremental placement/curing techniques tested. Lowest shrinkage stresses were generated by the bulk placement/curing technique.