Sementaatio

Cementation is a diagenetic or engineering process in which dissolved minerals precipitate from pore fluids and bind sediment grains together, producing a coherent rock or structural component. In geology, it refers to diagenetic lithification of porous rocks, with minerals such as calcite, silica, and dolomite precipitating as pore-filling cements. Cementation typically occurs during burial as circulating fluids transport ions and precipitate them at grain contacts, strengthening the rock. Common cement types include carbonate cementation (calcite or dolomite) and silica cementation (quartz or opal); iron oxide and phosphate cements also occur.

This process reduces porosity and permeability as pore spaces fill with cement. It is influenced by temperature, pressure, burial depth, and pore-water chemistry, including ion concentration, pH, and organics. Diagenetic cementation can overprint original textures and controls flow properties in reservoirs, while sometimes preserving delicate features. Cemented rocks gain strength but may become hydraulically tight.

In dentistry, cementation refers to bonding a prosthetic element such as a crown, bridge, inlay, or veneer to a tooth or implant using a dental luting cement. Common cements include zinc phosphate, zinc polycarboxylate, glass ionomer, resin-based cements, and temporary cements. Selection depends on retention, esthetics, biocompatibility, and whether retrievability is needed. The procedure typically involves surface preparation, cement mixing and application, seating of the restoration, excess cement removal, and curing or setting per cement type.