The retention of cast metal dowels fabricated by direct and indirect techniques.
OBJECTIVE
To explore the effect of fabrication technique, cement type, and cementation procedure on retention of cast metal dowels.


METHODS
Eighty intact single-rooted teeth were selected. The clinical crown was removed at the cementoenamel junction level. Each root was prepared to receive a cast metal dowel of 10-mm length and 1.45 mm in diameter. The 80 specimens were divided into two major groups of 40 based on fabrication technique (direct and indirect). Each group was further divided into four subgroups of ten based on the cement type (zinc phosphate and glass ionomer), and cementation procedure (with and without lentulo spiral). The dowels were subjected to a constantly increasing tensile force, in a universal Instron testing machine, at crosshead speed of 5 mm/min until failure.


RESULTS
The most significant factor to affect retention was the cementation procedure, as cementation with lentulo spiral produced greater retention than cementation without the use of lentulo spiral (p < 0.05); however, there seems to be a close interaction between fabrication technique, cement type, and cementation procedure (p= 0.051). The least retentive group was the one fabricated by direct technique, cemented with zinc phosphate without the use of lentulo spiral.


CONCLUSIONS
Fabrication technique does not affect retention of cast dowels, except when zinc phosphate was the luting agent and placed in the canal space without using a lentulo spiral. The cementation procedure had a significant effect on retention; thus, it is recommended that cementation should be done using the lentulo spiral.
Al-Omari
Wael M
WM
Department of Restorative Dentistry, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. womari@just.edu.jo
Zagibeh
Ayman M
AM
D000704:Analysis of Variance; D001641:Bicuspid; D002484:Cementation / Q000295:instrumentation / Q000379:methods*; D003735:Dental Casting Technique; D003738:Dental Cements; D017268:Dental Prosthesis Retention; D005899:Glass Ionomer Cements; D006801:Humans; D008670:Metals; D016062:Porosity; D011176:Post and Core Technique; D015036:Zinc Phosphate Cement
D003738:Dental Cements; D005899:Glass Ionomer Cements; D008670:Metals; D015036:Zinc Phosphate Cement