Threaded endodontic dowels: Effect of post design on incidence of root fracture

doi:10.1016/0022-3913(91)90159-T

The Journal of Prosthetic Dentistry

Volume 65, Issue 2, February 1991, Pages 179-187

https://doi.org/10.1016/0022-3913(91)90159-T Get rights and content

Abstract

The use of threaded endodontic dowels is a controversial issue. The purpose of this study was to compare the potential for root fracture resulting from the cementation of nine threaded and three nonthreaded endodontic dowel systems. The clinical crowns of 140 extracted premolars were removed at the cementoenamel junction. The teeth were randomly assigned to the following treatment groups of 10 teeth each: Group 1, endodontically instrumented but not obturated; group 2, instrumented and obturated; group 3, instrumented, obturated, and restored with custom-cast gold dowel and cores; groups 4 and 5, instrumented, obturated, and restored with prefabricated, nonthreaded dowels; and groups 6 through 14, instrumented, obturated, and restored with one of nine prefabricated, threaded dowels. All dowels were inserted according to manufacturer's directions, removed, and cemented with vinyl polysiloxane impression material. Each specimen was demineralized and cleared. Photographs at 1:1 magnification were taken to assess dowel fractures. Fisher's test and chi square analysis were performed to evaluate the differences between post types, and between posted and nonposted controls (p < 0.05.). The results indicate no statistically significant differences between dowel types when compared with each other, regardless of dowel shape, taper, or presence or absence of threads, or when compared to instrumented, nonobturated controls. The amount of remaining dentin and existing root morphology may be a determining factor for endodontically treated teeth to resist fracture during dowel placement.

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We aimed to compare the diagnostic accuracy of 5 cone-beam computed tomographic (CBCT) systems in detecting vertical root fractures (VRFs) and to assess whether fracture identification is affected by the presence of root canal filling.
Eighty extracted posterior teeth were included in this study. They were grouped according to the presence/absence of VRFs and the presence/absence of endodontic treatment. The teeth were then inserted in 5 dry skull/mandible assemblies. CBCT scans were performed using 5 different commercially available systems. Two observers evaluated the resultant multiplanar images twice for VRFs using a 3-point scale.
i-CAT (Imaging Sciences International, Hatfield, PA) showed the highest diagnostic accuracy in the detection of VRFs among the 5 investigated CBCT systems. The presence of root canal filling did not significantly decrease the ability to detect VRFs by all the studied systems. In the detection of VRFs in endodontically treated teeth, i-CAT was the most accurate, whereas 3D Accuitomo (J. Morita, Kyoto, Japan) was the least. Interobserver agreement was moderate for the i-CAT and fair for the rest of the studied modalities, whereas intraobserver agreement was good for the Scanora 3D (Soredex, Tuusula, Finland) and moderate for images from the other CBCT machines.
At the specified exposure parameters in the detection of VRFs in non–root canal–filled teeth, i-CAT showed the highest diagnostic accuracy followed by Planmeca Promax 3D (Planmeca, Helsinki, Finland), Scanora 3D, Accuitomo 3D, and Galileos 3D (Sirona Dental Systems, Bensheim, Germany), respectively. In the detection of VRFs in root canal–filled teeth, i-CAT showed the highest diagnostic accuracy followed by Planmeca Promax 3D, Scanora 3D, Galileos Comfort (Sirona Dental Systems), and Accuitomo 3D.
A 10-year retrospective study of the survival rate of teeth restored with metal prefabricated posts versus cast metal posts and cores
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Citation Excerpt :
By contrast, the conclusions drawn from Assif's in vitro study showed that the post design had no influence on the resistance to fracture.30 Screw posts presented higher resistance to tensile than cemented posts in an in vitro test,31 but they also produce more stress increasing the risk for root fracture.32–34 Adhesive systems could also stabilize teeth, moreover, posts cemented with adhesive materials have proved to be significant more resistance to fracture than those cemented with zinc phosphate.35,36
The aim of this retrospective study was to compare the cumulative survival rate of teeth restored with prefabricated posts and with cobalt-chrome cast post-cores.
112 endodontically treated teeth restored with prefabricated post and cobalt-chrome cast post-and-cores were evaluated. Teeth were considered as failures when were objective or radiologic sign of endodontic failure, post or root fracture, or when they had been extracted at the moment of the evaluation. Kaplan–Meier's method was used to reconstruct the survival curves of the restorations and to test the variable type of post-and-core restoration.
93 of the posts were still in function without clinical or radiographic signs of failure at the time of the examination resulting in a survival rate of 83.03% after a mean follow-up period of 10.08 years. When comparing the two techniques, prefabricated posts showed a slightly higher survival rate: 84.6% versus 82.6%.Focusing on tooth-type, maxillary premolars (n = 30) had the highest failure rate (30%) and also the lowest mean lifetime, with 6-and-a-half years. Maxillary incisors (n = 20) showed the highest success rate (5%) with only one case of failure.
The results showed no significant difference between both groups after a 10-year average follow-up.
Residual dentin thickness in bifurcated maxillary premolars after root canal and dowel space preparation
2006, Journal of Endodontics
Residual dentin thickness in 25 extracted bifurcated maxillary premolars after canal and Parapost preparation was assessed using acrylic muffle, after embedding in polyester resin and sectioned horizontally. After each procedure, the residual dentin thickness was compared to the original dentin thickness at eight aspects in three root levels. Residual dentin thickness measurements were calculated using photographs and a Digitizer. In the lingual aspect, the original dentin thickness averaged 0.99 mm (coronal slice) and 0.78 mm (middle slice). Dentin removal after dowel preparation was 31%. Three-way ANOVA with repeated measures was used. The difference in residual dentin thickness was highly significant regarding procedure (canal and dowel preparation, p < 0.0001), slice (middle, coronal, p < 0.0001), and the eight aspects (p < 0.0001). This in vitro study emphasizes the minimal dentin width of the buccal root, especially towards the bifurcation. Thus, dowels should be avoided in this root.
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: This investigation was supported by the University of North Carolina Faculty Research Support Grant.

^*: Assistant Professor, Department of Prosthodontics.

^**: Associate Professor, Department of Prosthodontics.

^***: Clinical Associate Professor and Acting Chairman, Department of Prosthodontics.

^****: Research Assistant, Department of Prosthodontics.

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Threaded endodontic dowels: Effect of post design on incidence of root fracture

Abstract

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

J Prosthet Dent

Dent Mater