Influence of timing of coronal preparation on retention of cemented cast posts and cores: Al-Ali K,...

Reprint requests to: DR YOAV GROSSMANN DEPARTMENT OF ORAL REHABILITATION CHAIM SHEBA MEDICAL CENTER TEL HASHOMER ISRAEL FAX: 972-3-674-2443 E-MAIL: [email protected] Copyright © 2003 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2003/$30.00 0 doi:10.1016/S0022-3913(03)00532-8 Noteworthy Abstracts of the Current Literature Influence of timing of coronal preparation on retention of cemented cast posts and cores. Al-Ali K, Talic Y, Abduljabbar T, Omar R. Int J Prosthodont 2003;16:290-4. Purpose. This study investigated the effect of coronal preparation by high-speed handpiece on the retention of cemented cast posts and cores. Materials And Methods. Cast posts and cores were fabricated for 90 extracted single-rooted human teeth cemented with zinc-phosphate cement and randomly divided into 6 groups of 15 specimens each. The 6 groups were matched randomly 2 by 2, such that 1 of each of the matched groups was subjected to a 4-minute period of high-speed preparation of the cores. Castings from the first pair (1 and 2) were subjected to an axially directed removal force using a universal testing machine 15 minutes from the start of cement mixing; castings from the second (3 and 4) and third (5 and 6) pairs were tested at 1 hour and 24 hours, respectively, having been stored in water at 37°C for the waiting periods. The forces required for dislodgment of posts from their prepared spaces were recorded. Data were statistically analyzed using two-way and one-way ANOVA and the Student t test. Results. The results showed increased mean retentive strengths of posts as the time to testing increased for both unprepared and prepared groups. Significantly higher mean retentive strengths of posts were recorded for unprepared compared to prepared groups tested at 15 minutes and 1 hour after cementation. Conclusion. High-speed preparation had a significant negative effect on the retentive strengths of posts tested at 15 minutes and 1 hour after cementation, but not on those tested at 24 hours. —Reprinted with permission of Quintessence Publishing. PENN, GROSSMANN, AND SHIFMAN THE JOURNAL OF PROSTHETIC DENTISTRY NOVEMBER 2003 513

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Transcript of Influence of timing of coronal preparation on retention of cemented cast posts and cores: Al-Ali K,...

Page 1: Influence of timing of coronal preparation on retention of cemented cast posts and cores: Al-Ali K, Talic Y, Abduljabbar T, Omar R. Int J Prosthodont 2003;16:290–4

Reprint requests to:DR YOAV GROSSMANN

DEPARTMENT OF ORAL REHABILITATION

CHAIM SHEBA MEDICAL CENTER

TEL HASHOMER

ISRAELFAX: 972-3-674-2443E-MAIL: [email protected]

0022-3913/2003/$30.00 � 0

doi:10.1016/S0022-3913(03)00532-8

Noteworthy Abstractsof theCurrent Literature

Influence of timing of coronal preparation on retention ofcemented cast posts and cores.Al-Ali K, Talic Y, Abduljabbar T, Omar R. Int J Prosthodont2003;16:290-4.

Purpose. This study investigated the effect of coronal preparation by high-speed handpiece on theretention of cemented cast posts and cores.Materials And Methods. Cast posts and cores were fabricated for 90 extracted single-rootedhuman teeth cemented with zinc-phosphate cement and randomly divided into 6 groups of 15specimens each. The 6 groups were matched randomly 2 by 2, such that 1 of each of the matchedgroups was subjected to a 4-minute period of high-speed preparation of the cores. Castings fromthe first pair (1 and 2) were subjected to an axially directed removal force using a universal testingmachine 15 minutes from the start of cement mixing; castings from the second (3 and 4) and third(5 and 6) pairs were tested at 1 hour and 24 hours, respectively, having been stored in water at 37°Cfor the waiting periods. The forces required for dislodgment of posts from their prepared spaceswere recorded. Data were statistically analyzed using two-way and one-way ANOVA and theStudent t test.Results. The results showed increased mean retentive strengths of posts as the time to testingincreased for both unprepared and prepared groups. Significantly higher mean retentive strengthsof posts were recorded for unprepared compared to prepared groups tested at 15 minutes and 1hour after cementation.Conclusion. High-speed preparation had a significant negative effect on the retentive strengths ofposts tested at 15 minutes and 1 hour after cementation, but not on those tested at 24 hours.—Reprinted with permission of Quintessence Publishing.

PENN, GROSSMANN, AND SHIFMAN THE JOURNAL OF PROSTHETIC DENTISTRY

NOVEMBER 2003 513