Multidisciplinary Treatment of Complicated Crown-Root Fractures: A Case Study.

Traumatic dental injuries usually occur among children and adolescents, with maxillary central incisors as the most often affected teeth. Complicated crown-root fractures are particularly challenging for esthetic and functional rehabilitation and often require a multidisciplinary approach. A 21-year-old male patient came to the Dental Clinic due to fractured maxillary incisors caused by trauma during a sporting activity. Clinical examination revealed horizontal fractures of teeth 7, 8, and 9, initiating in the labial cervical third and extending subgingivally on the palate, with exposed pulp tissues. On provisional repositioning and splinting the fragments, root canal treatment was performed. Definitive repositioning was accomplished by raising a full-thickness gingival flap, using fiber-reinforced composite posts, by an endodontist and an oral surgeon. Reattachment was accomplished under surgical conditions to ensure precise positioning of fragments by exposing the palatal aspect of the fracture lines and providing a dry operating field. Definitive composite resin veneers were performed after seven days.

The Ti-Mn system revisited: experimental investigation and thermodynamic modelling.

As the Ti-Mn phase diagram is part of numerous ternary and higher order systems of technological importance, the present paper defines phase relations which have been experimentally established throughout this work from 800 °C to the melting range based on Differential Thermal Analyses (DTA), X-ray powder diffraction, metallography and Electron Probe Micro Analysis (EPMA) techniques on ∼50 alloys, which were prepared by arc melting or high frequency melting under high purity argon starting from freshly cleaned metal ingots. Novel compounds were identified and reaction isotherms were redefined accordingly. In the Ti-rich region a novel compound TiMn was detected, sandwiched between the known phases: TiMn1-x (∼45 at% Mn) and TiMn1+x (∼55 at% Mn). In the Mn-rich region the hitherto unknown crystal structure of TiMn∼3 was solved from X-ray single crystal diffraction data and found to be of a unique structure type Ti6(Ti1-xMnx)6Mn25 (x = 0.462; space group Pbam (#55); a = 0.79081(3) nm, b = 2.58557(9) nm, c = 0.47931(2) nm), which consists of two consecutive layers of the hexagonal MgZn2-type Laves phase (TiMn2) and a combined layer of alternate structure blocks of MgZn2 type and Zr4Al3 type. Whereas TiMn can be considered as a line compound (solubility range <∼1 at%), the homogeneity regions of the Ti-Mn compounds are significant (determined by EPMA): TiMn1-x (44.0 to 46.6 at% Mn), TiMn1+x (54.6 to 56.3 at% Mn), Ti1+xMn2-x (MgZn2-type, 59 to 69 at% Mn at 1000 °C: -0.08 < x < 0.23), TiMn∼3 (unique type; 74 to 76.5 at% Mn) and TiMn∼4 (R-phase: Ti8(TixMn1-x)6Mn39, 80 to 84 at% Ti). Supported by ab initio calculations of the ground state energy for the Laves phase, the new experimental results enabled thermodynamic modelling of the entire Ti-Mn phase diagram providing a complete and novel set of thermodynamic data thus providing a sound basis for future thermodynamic predictions of higher order Ti-Mn-X-Y systems.

Noncarious cervical lesions restored with three different tooth-colored materials: two-year results.

INTRODUCTION: The aim of this two-year prospective clinical study was to evaluate and compare the clinical performance of three different adhesive esthetic materials in noncarious cervical lesions. MATERIAL AND METHODS: A total of 90 restorations (30 per material) were placed in 30 patients who ranged in age between 18 and 50 years and of both genders, by a single operator with no previous preparation. The restoration of noncarious cervical lesions was done with either a microfilled composite (Esthet.X/Dentsply/De Trey, Konstanz, Germany, and Prime&Bond NT/Dentsply/De Trey), a nanohybrid composite (TetricEvoCeram/Vivadent, Schaan, Liechtenstein, and AdheSE/Vivadent), or a compomer (Dyract eXtra/Dentsply/De Trey and Xeno III Dentsply/De Trey). All restorations were evaluated by independent examiners using a modified US Public Health Service criteria at baseline and after 12 and 24 months for six clinical categories. Data were analyzed statistically by Pearson's chi-square or the Fisher's exact test at 5% significance level (p<0.05). RESULTS: Results showed that most of the restorations were clinically satisfactory after 12 and 24 months, with no statistically significant differences among the three groups for all evaluated criteria. CONCLUSION: Treatment of noncarious cervical lesions using composite and compomer materials, combined with the appropriate adhesive systems and properly implemented restorative procedures, gives satisfactory results after a two-year evaluation period.