Comparison of the Load at Fracture of Turkom-Cera to Procera AllCeram and In-Ceram All-Ceramic Restorations

Purpose: This study investigated the occlusal fracture resistance of Turkom-Cera-fused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.
Materials and Methods: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37°C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.
Results: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 ± 164 N), In-Ceram (2042 ± 200 N), and Procera AllCeram (1954 ± 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram ( p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.
Conclusion: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.     

Intramuscular myxoma of the hypothenar muscles

Intramuscular myxomas of the hand are rare entities. Primarily found in the myocardium, these lesions also affect the bone and soft tissues in other parts of the body. This article describes a case of hypothenar muscles myxoma treated with local surgical excision after frozen section biopsy with tumor-free margins. Radiographic images of the axial and appendicular skeleton were negative for fibrous dysplasia, and endocrine studies were within normal limits. The 8-year follow-up period has been uneventful, with no complications. The patient is currently recurrence free, with normal intrinsic hand function.     

Some flexural properties of a nylon denture base polymer

Nylon denture base material could be a useful alternative to poly (methyl methacrylate) (PMMA) in special circumstances such as patient allergy to the monomer. The aim of this study was to evaluate the flexural properties of a nylon denture base material (Lucitone FRS), a conventional compression-moulded heat-polymerized (Meliodent), a compression-moulded microwave-polymerized (Acron MC) and an injection-moulded microwave-polymerized (Lucitone 199) PMMA polymers. The effect of aldehyde-free, oxygen releasing disinfectant solution (Perform) on these properties was also investigated. The flexural modulus and the flexural strength were assessed with a three-point bending test. Specimens were stored in water at a temperature of 37 degrees C for 30 days. For each material, half of the prepared specimens were randomly selected and immersed in the disinfectant 24 h prior to testing. Results were compared statistically at a confidence level of 95%. The result showed that in both the control and disinfected groups, the flexural modulus of nylon was significantly lower than the three PMMA polymers. The flexural strength of nylon was significantly lower than those of Meliodent and Acron MC but was comparable with Lucitone 199. A 24-h immersion in the disinfecting solution increased the rigidity of nylon denture base material.     

Non-vascularized fibular graft reconstruction after resection of giant aneurysmal bone cyst (ABC)

The aim of this study was to present the results of non-vascularized fibular graft for reconstruction of bone defects after en block resection of giant aneurysmal bone cyst (ABC) of the extremities. Between 1998 and 2006, three patients, aged 6, 8 and 23 years, with giant aneurysmal bone cysts were treated. The cysts were located in the humerus, proximal femur and metatarsal. All patients were given en bloc resection of the cyst followed by non-vascularized fibular bone graft, with the graft length ranging from 6 to 18 cm. All patients needed supplementary fixation with a single Kirschner wire or plate and screws. At the final follow-up, bony union was achieved in each case, and there was no recurrence, limitation of range of motion or disability. In addition, complete regeneration of the fibula at the donor site was seen in the two children. We propose a criterion for giant ABC, when the transverse diameter of the cyst is up to three times or more of the transverse diameter of the nearby bone, it is then called a giant ABC. Non-vascularized fibular graft is an optimal and valuable method for the reconstruction of bone defects after resection of giant ABC in the extremities.     

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The impact of recycling and repeated recycling on shear bond strength of stainless steel orthodontic brackets

PurposeTo compare Shear Bond Strength (SBS) of new, recycled and repeated recycled stainless steel orthodontic brackets with and without bracket base primer.Materials and methods120 extracted human premolar teeth and 120 premolar stainless steel orthodontic brackets were divided into six groups for 20 teeth each. Orthodontic brackets of four groups were sandblasted with 50 μm aluminum oxide powder and half of them were recycled for second time. Light cure orthodontic adhesive primer was applied for half of total brackets. Light cure composite was applied for all brackets and polymerization was carried out. Groups 1–6 were subjected to a shear force within half hour to simulate as done clinically with a universal testing machine (Shimadzu Trapezium X) until the bracket debond.ResultsThe results of this study demonstrated that the mean SBS of all groups were more than that recommended by Reynolds in 1975, there was no significant difference between new and recycled brackets. Only one group (repeated recycled without bond) has significantly lower SBS.ConclusionIt can be concluded that: sandblasted recycled orthodontic brackets can be used as an alternative to new brackets which might provide cost reduction and in case of using repeated recycled brackets, better to apply bonding agent on bracket base for more bond strength.