Retentive properties of a split-shaft threaded post: Cut at different apical lengths

Cohen, Beverly S.; Condos, Spyridon; Musikant, Barry Lee; Deutsch, Allan S.

doi:10.1016/0022-3913(92)90546-m

Cited by 21 publications

(15 citation statements)

References 13 publications

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“…This is due to the Flexi‐Post® having threads that actively engage the dentin as compared to the C‐Post® that relies on cement for retention. A post with the greater retentive property would be more resistant to dislodgement from the lateral stresses produced by occlusion ( Standlee et al, 1972 ; Deutsch et al ., 1985 ; Cooney, Caputo & Trabert, 1986; Brown & Mitchem, 1987; Millstein et al ., 1987 ; Saunders et al , 1988 ; Greenfeld et al ., 1989 ; Burgess et al ., 1992; Cohen et al ., 1992a ; Cohen et al , 1992b; Burns et al ., 1993). One would then expect the Flexi‐Post® to be more stable then the C‐Post® in relation to the retentive strength of the post in the root.…”

Section: Discussionmentioning

confidence: 99%

“…All teeth were endodontically instrumented with broaches and reamers. The root canals were not obturated and this technique is a standard test procedure for retentive tests found in the literature ( Standlee et al , 1972 ; Musikant & Deutsch, 1984; Deutsch et al ., 1985 , Brown & Mitchem, 1987; Burns et al ., 1990 ; Cohen et al ., 1992a ; Cohen et al ., 1992b; Cohen et al ., 1995a,b ). A post hole was prepared according to the manufacturer's directions (post holes length for Flexi‐Post® was 12·0 mm and for C‐Post® was 11·0 mm).…”

Section: Methodsmentioning

confidence: 99%

“…A post provides a substructure for retaining a core restoration in a root of a tooth. The retention of the post is therefore, very critical ( Trabert, Caputo & Abou‐Rass, 1978; Guzy & Nicholls, 1979; Cohen et al , 1992a ). The use of the of photoelastic stress analysis has been used to investigate the stress distribution for various prefabricated and cast post system ( Standlee et al , 1972 ; Henry, 1977; Standlee, Caputo & Holcomb, 1982; Musikant & Deutsch, 1984; Cooney, Caputo & Trabert, 1986; Burns et al ., 1990 ; Cohen, Musikant & Deutsch, 1992b; Cohen et al ., 1995a,b ).…”

Section: Introductionmentioning

confidence: 99%

“…The use of the of photoelastic stress analysis has been used to investigate the stress distribution for various prefabricated and cast post system ( Standlee et al , 1972 ; Henry, 1977; Standlee, Caputo & Holcomb, 1982; Musikant & Deutsch, 1984; Cooney, Caputo & Trabert, 1986; Burns et al ., 1990 ; Cohen, Musikant & Deutsch, 1992b; Cohen et al ., 1995a,b ). Numerous investigators have shown the endodontic post design and length to be crucial factors influencing the ability of a post to distribute stress under function and the retention of the post in the root ( Standlee et al , 1972 ; Henry, 1977; Standlee et al ., 1982; Musikant & Deutsch, 1984; Cooney, Caputo & Trabert, 1986; Burns et al ., 1990 ; Cohen et al ., 1992a ; Cohen et al ., 1992b; Cohen et al ., 1995a,b ).…”

Section: Introductionmentioning

confidence: 99%

“…The threaded split‐shank Flexi‐Post® 1 has demonstrated excellent retention with minimal functional stress ( Musikant & Deutsch, 1984; Deutsch et al ., 1985 ; Millstein et al ., 1987 ; Brown & Mitchem, 1987; Greenfeld et al ., 1989 ; Saunders et al ., 1988 ; Ross, Nicholls & Harrington, 1991; Burgess, Summitt & Robbins, 1992; Cohen et al ., 1992a ; Burns, Douglas & Moon, 1993; Cohen, Musikant & Deutsch, 1994). The Flexi‐Post® system has also been reported to provide favourable resistance to in vitro cyclic fatigue when compared to other prefabricated post systems ( Cohen, Deutsch & Musikant, 1993a,b).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Comparison of the retentive and photoelastic properties of two prefabricated endodontic post systems

Cohen¹,

Pagnillo²,

Musikant³

et al. 1999

J of Oral Rehabilitation

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This in vitro study compared the retention and photoelastic stress patterns from two loading conditions, vertical (133.2 N, 30 pounds) and oblique at a 26 degrees angle (133.2 N, 30 pounds) for two prefabricated post systems. The post studied were: (1) Flexi-Post (a split-shank threaded post) and (2) C-Post (a carbon fibre bound in an epoxy resin, passive double taper tier post). Two groups with 10 specimens per group were subjected to retentive forces with a universal testing machine (MTS 810 Material Testing Machine). In addition, two photoelastic test blocks were prepared with simulated root canals for each post studied. After cementation the photoelastic blocks were photographed before vertical and oblique loading and after loading. One-way analysis of variance (ANOVA) for retention data revealed a highly significant difference (P<0.0001) between groups. The Flexi-Post had a statistically higher mean retention force of 1180.6 N (265.9 pounds), while the C-Post had a mean of 171.8 N (38.7 pounds). Photoelastic analysis indicated minimal stresses for both the Flexi-Post and C-Post in the unloaded state. The C-Post showed asymmetrical apically stress patterns, while loaded in both states. The multi-tiered system of the Flexi-Post clearly distributes stress symmetrically, while the C-Post distributes stresses asymmetrically. The symmetric, even stresses and statistically higher retentive strength for Flexi-Post are more favourable than the asymmetric, uneven stresses and relatively low retentive strength for the C-Post.

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