Contamination of resin-matrix composites on chairside handling using latex or nitrile gloves: an in vitro study

The aim of this study was to evaluate the effect of different gloves and clinical environment on the contamination of resin-matrix composites for restorative dentistry. Specimens of nano-hybrid resin-matrix composite (n = 6) were divided in groups regarding the handling with (A) clinical spatula; (B) latex gloves; (C) latex or (D) nitrile gloves with human saliva; (E) latex or (F) nitrile gloves with human blood. After light curing, groups of specimens were analyzed by optical microscopy at magnification ranging from x30 up to x500 and by scanning electron microscopy at different magnification ranging from x50 up to x8000. Handling of resin-matrix composites with unpowdered nitrile gloves or clinical spatulas avoided the presence of contaminants. However, agglomerates of the resin-matrix composite itself became entrapped leading to a heterogenous morphological aspect. SEM images revealed the presence of corn-derived starch released from the powdered gloves. Also, the formation of micro-spaces (voids) occurred after handling with powdered latex gloves. Specimens handled with both type of gloves contaminated with saliva showed a conditioning layer composed of glycoproteins rolls and compounds including calcium-based chlorides, phosphates, and carbonates. Also, blood products were transferred from the contaminated gloves to the resin-matrix composites after handling. Thus, resin-matrix composite restorations are susceptible to contamination with debris from powdered gloves. Also, saliva or blood debris become adsorbed and entrapped in the resin-matrix composites during clinical handling leading to the presence of defects such macro- and micro-scale voids or contaminant agglomerates.