The incorporation of indium(
i) cations into zeolite beta by reductive solid-state ion exchange has been studied by TPR/TPO techniques, FTIR spectroscopy and a catalytic test reaction (isomerization ...of
m-xylene). Among the hydroxyl groups observed in zeolite beta, those vibrating at 3610
cm
−1 (bridged hydroxyls) were found to be preferentially involved in the exchange process, resulting in In
+ lattice cations. Reoxidation leads to the formation of cationic InO
+ species. After pyridine adsorption, In
+ and InO
+ can be distinguished by typical IR bands at 1446 and 1455
cm
−1, respectively. Details of the redox behavior of the cationic indium species are reported.
Dentigerous cyst is a developmental odontogenic cyst, which apparently develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown of an unerupted tooth. Management of ...dentigerous cyst in primary dentition needs special consideration regarding the preservation of the developing permanent tooth buds. A case of dentigerous cyst is reported in primary dentition of a 7-year-old female patient and its management. By extracting the infected primary teeth, opening the cyst and ensuring continuous drainage, it is possible to achieve spontaneous eruption of the involved permanent teeth into the dental arch even if they are badly dislocated. Simultaneous with the eruption of the permanent teeth, ossification of the bony defect can take place. The reparatory process is completed in one to two years, during this time the patient has been given a space-maintainer.
Combined surgical and orthodontic treatment of upper canine retention showed thorough development during the past decade. Depending on the axial position of the unerupted canine there are three ...methods for their alignment. When the axis of the unerupted canine is near vertical making a mucosal window is enough for deliberation of the crown. When the unerupted canine is covered by bone a palatinal or buccal corticotomy is necessary for the accessibility of the crown. When the unerupted tooth is positioned near horizontally redressment force or removal is advisable. Combined surgical and orthodontic method for alignment of unerupted canine may achieve excellent cosmetical and functional results.
