In vitro analysis of the fracture resistance of CAD-CAM monolithic zirconia molar crowns with different occlusal thickness

Objectives: To compare the fracture resistance and mode of failure of CAD-CAM monolithic zirconia crowns with different occlusal thickness. Material and methods: Forty CAD-CAM monolithic zirconia crowns with different occlusal thickness were randomly distributed into 4 experimental groups: 2.0 mm (group 1), 1.5 mm (group 2), 1.0 mm (group 3) and 0.5 mm (group 4). The restorations were cemented onto human molars with a self-adhesive resin cement. The specimens were loaded until fracture; the fracture resistance and mode of failure were recorded. The data were statistically analyzed with the one-way ANOVA followed by the Fisher's Exact test with Bonferroni's correction (p=0.05). Results: The fracture resistance values of all the specimens exceeded the maximum physiological occlusal loads in molar regions. All the crowns showed cohesive microcracks of the zirconia core; only 1 crown with a thickness of 0.5 mm was interested by a complete fracture. Conclusions: The occlusal thickness of CAD-CAM monolithic zirconia crowns did not influence either the fracture resistance and the mode of failure of the restorations; the occlusal thickness of CAD-CAM monolithic zirconia crowns can be reduced up to a lower bound of 0.5 mm keeping a sufficient strength to withstand occlusal loads; CAD-CAM monolithic zirconia crowns showed sufficient fracture resistance to be used in molar regions, even in a thin configuration (0.5 mm)

The Distraction Osteogenesis in Midfacial Hypoplasia

Distraction osteogenesis (DO) can generate new bone in a gap between 2 vascularized bone surfaces in response to application of graduated tensile stress across the bone gap. The authors present the clinical result in a cleft patient with severe maxillary deficiency treated by a rigid external distraction (RED) device. A boy complained of both masticatory and psychological problems because of cleft with severe midfacial retrusion. The treatment aimed to create a well-balanced facial profile, increase maxillary incisal display, create proper overjet and overbite, and align his dentition. By the RED system, the traction is applied to the maxilla through the dentition by an intraoral splint. A complete Le Fort I osteotomy was performed, including pterygomaxillary and septal disjunction, with mobilization. Once osteotomy was completed, the halo portion of the RED device was adjusted for the width of the neurocranium and was rigidly fixed around the head with 2 scalp screws on each side. A well-balanced facial profile and a good alignment of the dentition were obtained. The patients had considerable improvement in his self-esteem. Clinical reports have suggested that maxillary advancements achieved by distraction are more stable than those achieved with orthognathic surgery with a minimal influence on velopharyngeal competence

Reactive soft tissue preservation in large bone defects after tooth extractions: A cone beam study

Granulation tissue containing reactive soft tissue with potential multipotent stem cells can help socket healing following extraction. The aim of this study was to assess bone healing of maxillary large bone defects while maintaining reactive soft tissue

Reactive Soft Tissue Preservation in Maxillary Large Bone Defects

Granulation tissue containing reactive soft tissue with potential multipotent stem cells can help socket healing following extraction. The aim of this study was to assess bone healing of maxillary large bone defects while maintaining reactive soft tissue