Evaluation of Dimension and Bridging of Sella Turcica and Presence of Ponticulus Posticus in Individuals With and Without Cleft: A Comparative Study.

OBJECTIVE: Sella turcica abnormalities such as sella turcica bridging (STB) have been observed frequently among patients with craniofacial anomalies. Ponticulus posticus (PP) is an important structure and its presence causes complications during surgeries. Due to the importance of these structures, this study aimed to evaluate the prevalence of STB, PP, and dimensions of the sella turcica in individuals with and without cleft. DESIGN: A cross-sectional study. SETTING: Orthodontic and Radiology Departments in a public dental school, Tehran, Iran. PATIENTS: Eighty-three lateral cephalograms of individuals with cleft and ninety-two cephalograms of class I individuals without cleft. MAIN OUTCOME MEASURES: Length, depth, and maximum anterior-posterior diameter (APD) of sella turcica, presence of STB (classified as types 1, 2, and 3), and PP. RESULTS: In the group with cleft, 19.3% of individuals had type I, 65.1%, type II, and 15.7%, type III STB. In the group without cleft, 15.2% had type I, 73.9%, type II, and 10.9%, type III STB. In the group with cleft, 65.1% of individuals had no PP, 24.1%, incomplete, and 10.8%, complete PP while in the group without cleft, 56.5% had no PP, 29 31.5%, incomplete, and 12%, complete PP. CONCLUSION: The sella turcica dimensions, STB, and PP prevalence were not significantly different between individuals with and without cleft. The sella turcica length and prevalence of STB and PP were not affected by age, sex, and cleft type. However, the depth and the APD were affected by age.

Comparison of retention and fracture load of endocrowns made from zirconia and zirconium lithium silicate after aging: an in vitro study.

BACKGROUND: This study aimed to compare retention and fracture load in endocrowns made from translucent zirconia and zirconium lithium silicate. METHODS: Fifty-six intact human maxillary molars after being mounted in acrylic resin, were scanned to acquire biogeneric copies. Specimens underwent standard endodontic treatment and were prepared for endocrown up to 2 mm above the cementoenamel junction. The specimens were randomly divided into two groups of 28, and endocrowns were designed using biogeneric copies and milled from high-translucent zirconia disks (Zr) and zirconium lithium silicate blocks (ZLS). After cementation with dual-cure resin cement, all the specimens underwent thermomechanical aging, and pull-out retention test and compressive test were conducted (14 specimens were used for each test in each group, n = 14), and failure modes in both tests were evaluated. RESULTS: Independent samples t-test showed significant difference between the retention of Zr (271.5 N ± 114.31) and ZLS (654.67 N ± 223.17) groups (p value = 0.012). Compressive test results were also significantly different between Zr (7395.07 N ± 1947.42) and ZLS (1618.3 N ± 585) (p = 0.002). Failure mode of retention test was primarily adhesive failure at the cement-restoration interface in Zr group and cement-tooth interface in ZLS group. Failure modes of fracture test for Zr group were 7 non-restorable fractures and one restorable fracture while 6 specimens resisted compressive loads up to 8500 N without fracture. ZLS group showed 7 restorable and 7 non-restorable failures. CONCLUSIONS: Zr endocrowns showed significantly lower retention and higher fracture strength. Both materials seem to be suitable for fabrication of endocrown in clinical setup.

Comparison of Marginal and Internal Adaptation in Endocrowns Milled from Translucent Zirconia and Zirconium Lithium Silicate.

PURPOSE: This study aimed to compare marginal and internal adaptation in endocrowns made from translucent zirconia and zirconium lithium silicate using CAD-CAM technology. MATERIALS AND METHODS: Twenty-eight freshly extracted upper molars were mounted in acrylic resin and underwent root canal therapy and endocrown preparation up to 2 mm above the cementoenamel junction. Endocrowns were CAD-CAM milled from zirconium lithium silicate (ZLS) and translucent zirconia (Zr). Internal and marginal adaptation was assessed by the replica technique before cementation. Marginal adaptation was evaluated by a stereomicroscope (×32) before and after cementation and also after thermomechanical aging. RESULTS: The ZLS group showed significantly higher internal adaptation compared to the Zr group (P = 0.028), while the marginal adaptation differences, at different times with different methods, were not statistically significant (P > 0.05). Axiomarginal angle had the highest and axiopulpal angle showed the lowest adaptation in both groups. The cementation process and thermomechanical aging increased the marginal gap in both groups significantly (P < 0.001). The marginal gap assessed by the replica technique before cementation was 7.11 µm higher than direct view under a stereomicroscope with intraclass correlation coefficient of 0.797. CONCLUSION: Zirconia seems to be an acceptable material for endocrown with comparable internal and marginal adaptation to ZLS. Cementation and thermomechanical aging had significantly negative effects on marginal gap. The marginal gap assessed by the replica technique was higher than direct view under the stereomicroscope technique.