Biomedical subjects
L W Stockton
Publications and source records attributed to L W Stockton.
Factors affecting retention of post systems: a literature review.
STATEMENT OF PROBLEM: An extensive review of the published literature has revealed a wide divergence of opinion regarding the suitability of different post systems for endodontically treated teeth. As a result, the dentist has no clear guidelines concerning the selection of suitable post systems that will provide adequate retention while minimizing subsequent root fracture. PURPOSE: This study formulated, through the literature search, a set of guidelines to assist the dentist in selecting an endodontic post system that would optimize retention while limiting root fracture. RESULTS: For most clinical situations, the literature indicates that a passive parallel-sided post will, in the hands of the average practitioner, allow the dentist to successfully restore most endodontically treated teeth.
Vital pulp capping: a worthwhile procedure.
Despite the progress made in the field of pulp biology, the technique and philosophy of direct vital pulp capping remains a controversial subject. Clinicians are well aware of the immediate and long-term success rates after root canal therapy, but are less certain of the success of vital pulp capping. Researchers have demonstrated that exposed pulps will heal and form reparative dentin. It is realized now that the variable prognosis of vital pulp capping is predominately a restorative issue. The factors that can produce a successful vital pulp cap are discussed in conjunction with two popular techniques.
Management of accidental and iatrogenic injuries to the dentition.
This article discusses the restoration of teeth with extensive fractures extending beyond the attachment of the periodontal ligament, as well as the treatment of iatrogenic perforations observed during post space preparation. Various treatment procedures and their limitations are described, based on the authors' many years of clinical experience.
Cantilever fixed partial denture--a literature review.
In light of the increasing demand for fixed prosthetics by today's patients, the author felt the time was right for a review of an area of fixed prosthetics that is neither well understood nor well accepted. The cantilever fixed partial denture (FPD) requires more time to treatment plan and place than other comparable fixed prosthetics. However, if the necessary criteria are met, the final results can be very rewarding for the practitioner and the patient from both an esthetic and a functional standpoint. This article discusses various factors that impact on the practitioner's ability to place a cantilever FPD with the expectation of long-term success, as well as other related areas of treatment planning.
Retention and shear bond strength of two post systems.
The purpose of this study was to compare the retention and shear strength of teeth restored with the Para Plus post (P) and the C post (C1 and C2) systems. Twenty-four P, C1, and C2 posts each were placed 7 mm into recently extracted and endodontically treated maxillary anterior roots and luted with Ketac-Cem and Bis-Core respectively. In addition, 13 samples of each post type had a Bis-Core composite core placed. The tensile retention strength of the post and the shear strength of the post and core restorations when the core was loaded buccolingually at 45 degrees to the roots' long axis were determined at a strain rate of 1.3 mm/min. The C2 posts required significantly more tensile force (P < 0.0001) to remove them than the P or C1 posts. The shear strength of the post/core restorations was not significantly different (P < 0.04). The C1 restorations had 12 root fractures, the C2 restorations had 11 root fractures, and the P samples had six root fractures. It was concluded that the lack of stiffness of the C posts adversely affected the success of these restorations.
Post retention and post/core shear bond strength of four post systems.
As clinicians we continue to search for a post system which will give us maximum retention while maximizing resistance to root fracture. The introduction of several new post systems, with claims of high retentive and resistance to root fracture values, require that independent studies be performed to evaluate these claims. This study tested the tensile and shear dislodgment forces of four post designs that were luted into roots 10 mm apical of the CEJ. The Para Post Plus (P1) is a parallel-sided, passive design; the Para Post XT (P2) is a combination active/passive design; the Flexi-Post (F1) and the Flexi-Flange (F2) are active post designs. All systems tested were stainless steel. This study compared the test results of the four post designs for tensile and shear dislodgment. All mounted samples were loaded in tension until failure occurred. The tensile load was applied parallel to the long axis of the root, while the shear load was applied at 450 to the long axis of the root. The Flexi-Post (F1) was significantly different from the other three in the tensile test, however, the Para Post XT (P2) was significantly different to the other three in the shear test and had a better probability for survival in the Kaplan-Meier survival function test. Based on the results of this study, our recommendation is for the Para Post XT (P2).