The Injection Molding Technique (IMT) is a powerful therapeutic option in the restorative field that aims to improve the esthetics and function of the teeth. It is a repeatable and predictable technique that requires a direct/indirect procedure to transform the digital tooth design and the wax-up (analog or digital) into a definitive composite restoration. The traditional technique involves the application of a single layer of flowable composite using a silicone index. With the introduction of the innovative Customized Hybrid Index (CHI), it is possible to use both flowable or heated (thermoviscous) composites, with separate layering of dentin, enamel, and opalescent incisal masses, thus improving the esthetic result compared with the traditional technique. The CHI is a multilayer hybrid stent consisting of a 60 Shore A highly transparent silicone in which composite (fluid or thermoviscous) is injected, a 70 to 80 Shore A silicone used as a distal support, and a thermoformed resin shell used as a rigid outer layer. The holes needed for the injection phase are calibrated according to the type of compule tip or syringe needle used. The purpose of the present article (part 1) is to illustrate the innovative operating protocol for the implementation of the IMT. In the next article (part 2), all the clinical indications relating to this technique, which involves the use of both flowable and heated composites, will be defined and described. Keywords: adhesive dentistry, composite Injection Molding Technique (IMT), Customized Hybrid Index (CHI), esthetic rehabilitations, flowable injection technique, injectable technique, restorative dentistry