Instruments, appliances, etc. for crown-, bridge- and metal work : Hollingsworth system of crown- and bridge-work. Various methods of setting Logan crowns / S.S. White Dental Manufacturing Co.

  • S.S. White Dental Manufacturing Company.
Date:
1911
Catalogue details

Licence: In copyright

Credit: Instruments, appliances, etc. for crown-, bridge- and metal work : Hollingsworth system of crown- and bridge-work. Various methods of setting Logan crowns / S.S. White Dental Manufacturing Co. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    SIMPLICITY The simplicity of the Logan Crown is evident in the fact that it is practically a complete crown when bought by the dentist. It requires no fitting and cementing or soldering to attach pin and crown, as is the case with all-porcelain crowns in which pin and crown are separable. The work therefore is simplified and the risk of breakage incident to soldering eliminated. To put it another way: The operator, instead of having two joints to make has but one, the other having already been made secure by the manufacturer, who has also provided every facility for assuring the security of the one to be made. The leading operators, in preparing a root surface, invariably bevel the root on its labial side to permit of the lapping of the labial face of the crown at its cervical border over the beveled root, thus giving an artistic as well as entirely satisfactory fit at the gum margin. They recognize that a crown fitted in any other way will present an inartistic appearance, and may irritate the gum. The Logan Crown is constructed to meet this idea, and the surface of the crown which comes in contact with the root is designed as nearly ideal as we can make it, requiring little grinding to fit the average root in the normal state. The cup-shaped base of the crown enables the operator to more readily grind and fit the crown to the root than when the base is solid or convex in form, inasmuch as only a thin wall is to be ground instead of a solid mass from the outer surface to the post. ADAPTABILITY Through its own inherent excellences of form and the number of different molds which are avail- able for selection, the Logan Crown is almost universally adaptable. The only cases to which it cannot be applied are those in which the shut of the jaws is extremely short, and those in which there is marked recession of the gum. There is also an occasional instance where the root to be crowned is too small and frail to receive the full size Logan post. This can usually be remedied by riling down the post to suit. The nearly universal adaptability of the Logan is evidenced by the facility with which it lends itself to different methods of working. It can be mounted with band or cap or without, and what- ever method is used, the result is a strong, durable, satisfactory crown. When a Logan Crown is to be mounted on a bicuspid with bifurcated root, all that is necessary is to split the post (Figs. 5 and 6). SELECTION Proper selection has an important bearing upon the fitting and mounting of Logan Crowns just as in other porcelain teeth. The number and variety of molds of these crowns afford ample oppor- tunity for the wise exercise of this faculty. Taking advantage of this opportunity for selection, and considering the ease and security with which it can be mounted, the Logan is the cheapest crown at the service of the dentist. Sold as single crowns, and in sets of 2 (centrals, laterals, or cuspids), 4 (centrals and laterals), 6 (centrals, laterals, and cuspids), and 4 (bicuspids).