Caries can cause defects in the hard tissue of the teeth. By filling these defects, tooth filling is an effective method to maintain the aesthetic properties of the teeth as well as the complete form and chewing function of the teeth. 
The purpose of tooth filling is to restore the tooth to its former function and give it an aesthetic appearance. For this purpose, dental filling materials have changed over the years and their aesthetic properties have improved. Due to its effectiveness and cost, amalgam is a restorative material that has been frequently preferred in the past to fill the cavities in the posterior teeth. However, today, the use of amalgam filler has decreased due to the insufficient aesthetic properties and the toxic product.  Resin composites have become an aesthetic alternative to amalgam restorations.
The tooth-colored composite can be applied without causing excess material loss from the tooth surface. The caries are cleaned and the tooth surface is prepared, the adhesive called bonding is applied to the tooth and composite filling is made on it. It is polymerized by applying a beam to the composite surface. Then, it is polished to the filling surface and adapted to the tooth surface.
With the changing health standards, aesthetic demands and environmental awareness of people, resin restorative materials have become the clinical filling preference of doctors and patients in the clinic. 
Made of porcelain, inlay and onlay have superior aesthetic properties, are indirect fillings prepared in a laboratory environment. They are the methods applied when the loss of substance in dental tissues is high. The caries of which the caries are cleaned are taken and prepared by the technician in the laboratory with porcelain. As it is prepared on the plaster model, the technician can see the filling from all aspects, and can perfectly match with the gum and adjacent tooth. The prepared porcelain filling has adhered to the surface of the tooth with special adhesive systems. Advances in adhesive dentistry have led to increased use of indirect restorations. Indirect composite techniques are more advantageous than direct composite filling techniques as they form appropriate occlusal and interproximal anatomy, reduce polymerization shrinkage stress and increase the degree of transformation. 
Composite fillers can wear out over time. Porcelain filler is more aesthetic than composite and has no coloration problem. The beam applied for polymerization in composite filling may cause shrinkage. As a result, leakage may occur from the composite edges and
As a result, secondary caries may occur. Researches based on resin
It showed that both the color and surface roughness of the dental restorative materials were affected after waiting in low pH beverages.  The problem of shrinkage in porcelain has been minimized, so the risk of leakage is low.
 Gong Y. The developmental history of the dental filling materials. Zhonghua Yi Shi Za Zhi. 2008
 Rasines Alcaraz MG, Veitz-Keenan A, Sahrmann P, Schmidlin PR, Davis D, Iheozor-Ejiofor Z. Direct composite resin fillings versus amalgam fillings for permanent or adult posterior teeth. Cochrane Database Syst Rev. 2014
 Lu PY, Chiang YC. Restoring Large Defect of Posterior Tooth by Indirect Composite Technique: A Case Report. Dent J (Basel). 2018
 Guler S, Unal M. The Evaluation of Color and Surface Roughness Changes in Resin-based Restorative Materials with Different Contents After Waiting in Various Liquids: An SEM and AFM study. Microsc Res Tech. 2018