[Longevity of restorations in composite and etched porcelain].

Due to continuing alterations in composition of dental products and materials, prognoses about longevity of restorations in composite or etched porcelain are extremely difficult to make. Strength, wear resistance and resistance against disintegration determine durability of stress bearing restorations. Elasticity in combination with bond strength are determinant for prevention against premature leakage. Indication, cavity form and careful handling of the materials are prerequisites for longevity of the restoration. The prognosis of the favourably located but stress bearing class IV is far better than that of the unfavourable located, non stress bearing class V-composite restoration. For the etched porcelains, the veneers offer the best perspectives with respect to durability thanks to the favourable shrinkage pattern.