Flexural Strength and Optical Characteristics of High Translucency Zirconia

Objective: High translucency zirconia has been developed for esthetically demanding dental cases with the objective of improving light transmittance. The purpose of this in vitro study is to compare the translucency and flexural strength of high translucency zirconia with conventional zirconia and lithium disilicate ceramics, all of which are options for indirect dental restorative applications. Methods: Three dental ceramic materials were selected: Group 1: conventional zirconia; group 2: high translucent zirconia; and group 3: lithium disilicate glass-ceramic. Fifteen disk-shaped specimens (10mm in diameter) of each material were fabricated at 0.5mm, 0.75mm, and 1 mm thicknesses as subgroups A, B, and C respectively (n=135). The morphologies of the specimens were observed by a scanning electron microscopy at 5000X magnifications. Translucency and flexural strength of all specimens were measured using spectrophotometry and biaxial flexural testing respectively. The data was analyzed by ANOVA followed by post-hoc test (p\u3c0.05). Results: Conventional Zirconia and lithium disilicate showed the highest and lowest mean flexural strength values respectively. Flexural strength of all 3 ceramic materials did not show significant difference with different material thicknesses. Lithium disilicate and conventional zirconia of equal thicknesses showed the highest and lowest translucency values respectively. Translucency of all 3 ceramic materials decreased with increasing material thickness. Conclusion: High translucency zirconia did not show superior translucency compared to lithium disilicate. Thus, high translucency zirconia should be carefully used in the esthetic zone depending on the translucency needed for a successful restoration. The flexural strength of conventional zirconia was significantly higher than high translucency zirconia and lithium disilicate. Therefore, the mechanical properties of high translucency zirconia may be of concern when planning for more than three unit FPDs in the posterior area

Transmigration of impacted mandibular canines-report of 4 cases

Intraosseous movement of an unerupted tooth across the midline of the jaw is known as dental transmigration. This infrequent event is mostly found in the mandibular canines. There are four new cases of mandibular canine transmigration presented here. The literature on this anomalous phenomenon is also reviewed

Transmigration of Impacted Mandibular Canines: A Report of Four Cases

Intraosseous movement of an unerupted tooth across the midline of the jaw is known as dental transmigration. This infrequent event is mostly found in the mandibular canines. There are four new cases of mandibular canine transmigration presented here. The literature on this anomalous phenomenon is also reviewed

Knowledge of Emergency Management of Traumatized Teeth among Schoolteachers in Mashhad, Iran

Background and aims. Dental trauma is an important oral health problem in children that requires immediate and appro-priate management for long term success. The aim of this study was to evaluate the knowledge of elementary school teach-ers about emergency management of traumatic dental injuries in children. Materials and methods. A total of 163 teachers from 21 elementary schools from Mashhad, Iran participated in this study. Data were collected using a two-part questionnaire comprised of questions regarding demographic data and partici-pants' knowledge about dental trauma. Results. The level of the teachers' knowledge was moderate (53.3%). Of the 163 participants, 104 (63.8%) were females and 59 (36.2%) were males. Among several predictors that were surveyed in this study, only the age of respondents signifi-cantly impacted the teachers' knowledge (P = 0.004). Conclusion. The results of this study showed the moderate level of knowledge of teachers regarding emergency manage-ment of traumatized teeth. Adding dental trauma management courses in the teacher training curriculum and requiring teachers to be updated in regards to this issue can improve their knowledge and thus led to better management of traumatic dental injuries in children