Influence of Radius of Curvature at Gingival Embrasure in Connector Area on Stress Distribution of Three-Unit Posterior Full-Contour Monolithic Zirconia Fixed Partial Denture on Various Amounts of Load Application: A Finite Element Study.

OBJECTIVES: To test the hypothesis that radius of curvature at gingival embrasure in connector area significantly affects the fracture resistance of full-contour monolithic zirconia three-unit posterior Fixed partial denture (FPD) on various amounts of load application. MATERIALS AND METHODS: In this study, two types of three-dimensional finite element models of a three-unit posterior full-contour monolithic zirconia FPD with two gingival embrasure radii (rGE I, 0.45 mm and rGE II, 0.25 mm) were constructed. The components modeled through finite element modeling were subjected to 400, 600, and 800 N vertical loads at the central fossa of the pontic, and further analysis was carried out. RESULTS: All the results were displayed by post-processor finite element analysis software (ANSYS). The study revealed that with increase in the amount of load application as well as decrease in the gingival embrasure radii, stress concentration values were increasing gradually for both the full-contour monolithic zirconia FPD. CONCLUSION: The fracture resistance of the zirconia posterior FPD was significantly affected by the gingival embrasure radii and the mode of load application. When there is a clinical situation of heavier occlusal forces, the fracture resistance can be increased by designing greater gingival embrasure radii in the connector region.

Full mouth rehabilitation of the patient with worn dentition using full-contour monolithic zirconia prostheses at an increased vertical dimension of occlusion: a case report / 대한치과보철학회지

Excessive occlusal wear results in unacceptable damage to the occluding surfaces, and can cause pulpal injury, occlusal disharmony, impaired function, and aesthetic deformity. Patients with severely worn dentition need to be classified as several categories relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. When treating patients classified as those who have excessive wear without loss of occlusal vertical dimension but with limited space, we could consider treating them at an increased vertical dimension of occlusion. Treatments at an increased vertical dimension of occlusion may provide stability, given that the amount of its increase was minimal, and a perfected occlusion was achieved after enough stabilization period. A 50-year-old male visited the department of Prosthodontics in Yonsei University Dental Hospital with the chief complaint of worn teeth on lower anterior area. Reconstruction at an increased vertical dimension of occlusion was planned. After the compatibility of the new vertical dimension of occlusion had been confirmed under interim fixed restorations, definitive fixed restorations composed of full-contour monolithic zirconia prostheses were placed. This case presents that a satisfactory clinical result was achieved by restoring the worn dentition at an increased vertical dimension of occlusion with an improvement in esthetics and function.