Endocrown as an alternative method of restoring the crown part of the tooth. Literature review

The prevalence of caries complications is high, which makes endodontic treatment relevant, although it reduces tooth strength. The prognosis of endodontically treated teeth is favorable with quality treatment and restoration, where pericervical dentin is important. Composites are suitable for small cavities, but are inferior to enamel in terms of strength. For molars, posts are often used, but their choice requires caution due to the risk of root weakening and cracking. It is important to avoid excessive root preparation while preserving the root structure. The use of posts should be justified, especially in short/fragile roots or obliterated canals. Endocoronca is a minimally invasive restoration for endodontically treated teeth that restores the anatomical crown by filling the pulp chamber. It is indicated in cases of significant tissue loss and limited space. Success rate is 94–100% within 36 months. The main complication is debonding (71%). Fewer root fractures compared to crowns (6% vs. 29%). Composites, ceramics, and polymer-infused ceramic network (PICN) are used in dentistry. PICN combines the strength of ceramics with the elastic modulus of a composite, and is suitable for chewing teeth. Lithium disilicate (LS2) is processed by CAD-CAM, becomes stronger after heating and is ultimately fracture resistant. PICN is closer to enamel in hardness than LS2 and zirconium dioxide (ZrO₂), but LS2 wears down enamel more, unlike the latter. ZrO₂ is stabilized with yttrium to improve properties. The Russian company ZirconCeramics produces Ziceram multilayer blanks. Studies show that Russian zirconium dioxidebased ceramics are superior to their Chinese counterpart in terms of strength. Two-year observations of crowns made of Ziceram T have shown their high strength, hygiene and biocompatibility. Domestic zirconia is justified for CAD/CAM designs of lateral teeth, but is poorly studied, especially for endocrowns. Surface modification of zirconia improves adhesion. Methods to improve adhesion are divided into: mechanical (sandblasting, acid etching), chemical (10-MDP) and combined (APC protocol: sandblasting, MDP primer, fixation). Clinical studies show a high survival rate for zirconia endocoronets, although studies are rare and short in duration. The CAD/CAM system within the “chairside” technology makes it possible to fabricate restorations quickly, including with new materials such as CEREC Tessera (lithium disilicate with virgilite). The use of domestic ceramic materials and the study of express modes of their syntherization are relevant for import substitution.

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