Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Prosthesis Retention”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMed2002

Effect of length and diameter of tapered posts on the retention.

The force transmission of tapered unthreaded posts along the root has been reported to be homogenous but their retentive strength was found to be lower compared with those of parallel unthreaded or other kinds of threaded posts. The purpose of this in vitro study was to investigate the effect of length and diameter on the retentive strength of sandblasted tapered prefabricated titanium posts (Erlangen post system). Posts with constant taper angle but with three different lengths (9, 12, 15 mm) and apical diameters (0.5, 0.9, 1.1 mm) were cemented using zinc phosphate cement into the prepared and roughened post spaces of 90 intact anterior teeth. The post retention concerning length and diameter, being independent from each other, was measured by a tensile force test. The retentive strength was found to be proportional to the length as well as to the diameter of the posts. The mean minimum strength (181 +/- 14 N) recorded for the thinnest and shortest post was significantly lower than that of mean maximum strength (612 +/- 85 N) obtained from those of the thickest and longest post. Proportional bond strengths of the posts comprising their surface areas ranged between 6.8 and 7.9 N mm(-2) which were not significantly different between any group. The retention was effected strongly with the increase in the length (approximately 100%) than with the increase in the diameter (approximately 60%). Concerning the posts tested in this study, it is concluded that some caution should be exercised in the choice of post with appropriate length rather than diameter for the tooth concerned.

Cementation↗
PubMed1992

Effect of eugenol-containing endodontic sealer on retention of prefabricated posts luted with adhesive composite resin cement.

Reported studies have implicated eugenol in the reduction in retention of restorations luted with chemically cured composite resin cement. This study investigated the effect of residual eugenol in the root canal on the retention of ParaPost dowels cemented with Panavia EX composite resin. An attempt was also made to identify and to determine the most effective cleansing procedure. Findings of this study demonstrated a substantial decrease in retention of posts luted with Panavia composite resin cement in the presence of eugenol. Irrigation with ethyl alcohol (ethanol) or etching with 37% phosphoric acid gel was found to be effective in restoring the resistance to dislodgment of the posts, but alcohol produced the most consistent and reliable results.

Acetone↗
PubMed1992

Dental implants to rehabilitate a patient with an unrepaired complete cleft of the hard and soft palate: a clinical report.

Prosthetic rehabilitation of an edentulous adult with a complete residual cleft of his palates is presented. Lack of retention of his prosthesis made speech and eating difficult. Four osseointegrated dental implants were used to join the right and left maxillae and to provide mechanical retention for a complete overdenture obturator to improve function.

Cleft Palate↗
PubMed1993

Pins for direct restorations.

Self-threading dentine pins permit the retention of large complex direct restorations but there are problems associated with their placement. Strain and crazing of dentine following pin insertion and pulpal and lateral perforations are common. Perforations can be avoided by operator awareness of tooth morphology. Strain and crazing has been found to be minimized by unscrewing the pin slightly after insertion, by using pins with a tap thread, and by using the smallest pin possible. Twist drill form and dulling affects the pin channel shape which in turn influences pin seating. A lack of standardization of pin and twist drill diameter and length has been implicated as the cause of poor pin retention. Manufacturers, in an attempt to standardize the depth of penetration of pins, have incorporated shoulders at the midpoint of the pin, which has met with varying success. More research in the area of limiting pin penetration is necessary, as well as attempts to improve the quality control of pin and twist drill manufacture.

Dental Cavity Preparation↗
PubMed2006

[The effects of remain of residual tooth on retention of post-core crown system].

This study was aimed to assess the effects of remain of residual tooth on the retention of postpost-core was made,casted and cemented. The post-core was tested at the speed of 10 mm/min on the Instron4302, and the retention force was recorded. Other samples were made and subjected to the test for cohesion of polymethylmethacrylate and metal. The result showed that retention significantly increased with the adding of the residual tooth. When the length of post was longer than 8 mm and 1 mm was added to tooth remain, the difference in retention between the two groups was statistically significant. It was noted that there existed relationships of retention to length of post and tooth remain, of cohesion to length of post and tooth remain, and of frictiion resistence to length of post and tooth remain; moreover, the relevant linear regression equations were obtained. So during the tooth preparation of post-core system, the tooth tissue should be reserved as much as possible.

Crowns↗
PubMed1993

The significance of retention in post and core restorations.

Endodontically-treated, pulpless teeth tend to become brittle and loose their natural resistance to intraoral functional stress. To retain the core to the root, posts are placed in such teeth. This article presents the rationale for placing the posts, reports past results, and discusses the current materials and implementation procedures. Understanding those principles is the learning objective of this article.

Acrylic Resins↗
PubMed2005

Restorative treatment of cervical lesions with resin composites: 4-year results.

PURPOSE: To verify the clinical behavior of two resin-based composites with different Young's modulus (AElite Fil and Elite Flo) in the restoration of carious and non-carious cervical lesions after 48 months of clinical service. METHODS: 116 restorations with the two different materials (60 with AElite Fil and 56 with AElite Flo) were performed in 15 patients and controlled for 48 months. Retention rate and USPHS criteria were recorded at 6, 12, 24, 36 and 48 months. RESULTS: The retention rate was 66% for AElite Fil in carious and non-carious lesions and 65 and 47% for AElite Flo in carious and non-carious lesions respectively at 48 months. A decrease of quality of restorations in time was recorded with all USPHS criteria, with no statistically significant difference between materials tested.

Acrylic Resins↗
PubMed1993

Ultrasonic removal of dentine pins.

Replacement of pin-retained amalgam restorations is complicated by the loss of prime pin sites and remaining pin sites posing anatomical problems. Self-threading dentine pins can be removed with an ultrasonic handpiece, and the pin site reused with a large pin. Retention of replacement pins is similar to original pins. Pin removal after experimental placement takes a considerable time (< 15 min), but pin removal from extracted pin-restored teeth is much quicker (mean of 45 s). The reuse of primary pin sites allows uncomplicated replacement of pin-retained amalgams, and is a useful clinical technique.

Analysis of Variance↗
PubMed2004

A comparison of the in vitro retentive strength of glass-ionomer cement, zinc-phosphate cement, and mineral trioxide aggregate for the retention of prefabricated posts in bovine incisors.

The purpose of this study was to compare the retentive strength of zinc-phosphate cement, glass-ionomer cement, and mineral trioxide aggregate (MTA) cement in the retention of prefabricated posts. The root canals of 60 bovine incisors were prepared and obturated with warm gutta-percha. Post space was prepared, the smear layer removed, and posts were luted with zinc-phosphate cement, glass-ionomer cement, or MTA. The specimens were stored at 37 degrees C and 100% humidity for 2 weeks, and then subjected to increasing axial tensile forces by an Instron machine until bond failure occurred. Data were analyzed by a one-way ANOVA and a Tukey-Kramer multiple comparison test. The retentive strengths of zinc phosphate and glass-ionomer cements were statistically equivalent, and significantly greater than MTA (p < 0.001), which suggests that zinc phosphate or glass-ionomer cement may be superior to MTA when used as luting agents for posts in endodontically treated teeth.

Aluminum Compounds↗
PubMed1999

The implant neck: smooth or provided with retention elements. A biomechanical approach.

A combined three-dimensional and axisymmetric finite element analysis was made of the effect upon the peak interfacial shear stress of providing an axially loaded mandibular dental implant with retention elements all the way up to the crest of the implant as opposed to a smooth neck. The effect of increased wall thickness of the implant and of using bi-cortical fixation as opposed to uni-cortical fixation was also studied. Retention elements at the implant neck were found to bring about a major decrease in the peak interfacial shear stress. Increased wall thickness and bi-cortical fixation also resulted in decreased peak interfacial shear stress but this effect was minor. The interpretation of this was that all these three measures increase the capacity of the implant to carry axial loads. Thus from a biomechanical viewpoint it appears to be advantageous to provide the neck of screw-shaped implants with retention elements, for example a rough surface of suitable micro-architecture and/or a micro-thread. It is furthermore suggested that retention elements at the implant neck will counteract marginal bone resorption in accordance with Wolff's law. This paper is a revision of: Hansson, S. (1997) Some steps to improve the capacity of dental implants to resist axial loads. In: Hansson, S., ed. Towards an optimized dental implant and implant bridge design: A biomechanical approach. Thesis. Göteborg: Chalmers University of Technology.

Alveolar Process↗
PubMed2001

Retention of cast posts cemented with zinc phosphate cement using different cementing techniques.

PURPOSE: This study compares the effect of different cementation techniques on the retention of cast posts and cores. MATERIALS AND METHODS: Twenty-four extracted single rooted human teeth were used in this study. After routine preparation of the root canals, the canal space was enlarged with reamers. Direct post patterns were made with acrylic resin. Castings were fabricated using Ni-Cr-Mb alloy. Zinc phosphate cement was used as a luting agent using 4 different methods of cement introduction to the root canal space. This created 4 treatment groups consisting of 6 teeth in each group. In Group A, the cement was applied over the posts only. For the specimens in Group B, the cement was introduced into the root canals with a spiral filler and applied over the posts. In Group C, cement was injected into the root canals and then applied over the posts. Finally, for the specimens in Group D, cement was injected into the root canals and a spiral was used to spread it into the root canals, and cement was also applied over the posts. After cementation, teeth were stored in saline solution. The tensile retentive force of cast posts was evaluated using the Instron testing machine (Instron, Canton, MA). RESULTS: The retention obtained by the 4 techniques differed significantly (p <.05). The highest tensile force to post dislodgment was observed in Group D, and the least was in Group A. Analysis of variance test revealed a highly significant difference between groups (p <.0001). According to the Fisher exact test, there was a significant increase in retention from Group A to Group D (p <.05). CONCLUSIONS: Under the conditions of this study, the injection of cement into a root canal space followed by the use of a spiral resulted in the highest level of post retention. Retention was reduced when cement was placed using a Lentulo spiral alone (Kerr/Sybron Corp, Romulus, MI), a Jiffy tube (Teledyne Water Pik, Allegheny Teledyne Co, Fort Collins, CO) alone, or by application to the post only. J Prosthodont 2001;10:37-41.

Acrylic Resins↗
PubMed2000

Selection of materials for post cementation.

Many types of cement are available for post cementation, each with advantages and disadvantages. For posts with adequate mechanical retention, zinc phosphate is a good choice for patients for whom fluoride release is not considered essential. Posts with compromised mechanical retention benefit from use of a resin-modified glass-ionomer cement, which also releases fluoride. Composite resin cements should be reserved for rare cases where mechanical retention is so compromised that use of a resin-modified glass-ionomer cement provides inadequate retention. Great care is required when using composite resin cements to ensure optimum performance and avoid the creation of difficult-to-remove excess cement. Clinicians should be aware that posts cemented with resin-modified glass ionomer or composite resin cements may be difficult or impossible to remove if access to the root canal system is subsequently required.

Cementation↗
PubMedDate not supplied

Four post-and-core combinations as abutments for fixed single crowns: a prospective up to 10-year study.

PURPOSE: In the present prospective study, four different post-and-core systems were evaluated over a period of up to 10 years. MATERIALS AND METHODS: Fifty endodontically treated teeth in 31 patients were randomized to one of four groups for post-and-core placement: Group 1 received conventional tapered cast posts and cores (n = 14); group 2 received ParaPost system prefabricated gold posts with cast cores (n = 13); group 3 received ParaPost system cast posts and cores (n = 13); and group 4 received Radix-Anchor posts (n = 10). Clinical and radiologic evaluations were made. RESULTS: One post and core in group 2 was functioning well 58 months after placement when the patient died. No posts and cores in groups 1 or 2 had been lost or had any complications, one in group 3 had been lost because of a root fracture after 108 months, and two in group 4 had been lost after 54 and 88 months, respectively, because of loss of retention. The final treatment result for 46 of the 49 remaining posts (30 patients) was successful. The overall failure rate was 6%. There were no statistically significant differences between the four groups. CONCLUSION: If recommended procedures are strictly followed, posts and cores can serve as abutments for fixed single crowns with satisfactory long-term results.

Adolescent↗
PubMed2006

Indirect restorations on teeth with reduced crown height.

UNLABELLED: Patients may present with a need for indirect restorations (crowns, inlays, etc), but have teeth with short clinical crown height. The management of problems presented by such teeth relates mainly to preventing loss of the restoration and the maintenance of the health of pulp in an already compromised tooth. Traditional techniques for increasing resistance form and retention, together with the option of surgical crown lengthening, will overcome problems associated with short crowns in many cases. However, these methods are not a universal solution. Contemporary techniques, utilizing adhesive dentistry, and the Dahl concept have an increasing place in the management of such cases. CLINICAL RELEVANCE: The Dahl concept and adhesive dentistry may supplement traditional techniques when providing and retaining indirect restorations.

Crowns↗
PubMed1997

The effect of cementing procedures on retention of prefabricated metal posts.

Twelve prefabricated posts were cemented in extracted teeth with zinc phosphate cement, 14 with resin cement after the canals were acid etched and 14 with zinc phosphate cement after acid etching. After thermocycling, specimens were subjected to a straight-line tensile force. The posts cemented with resin cement had significantly higher tensile strength than those cemented with the two zinc phosphate cement treatments.

Acid Etching, Dental↗
PubMed1993

Keeping implant screws tight: the solution.

Retrievability is the major advantage of screw-retained implant restorations compared to cement retention; however, implant screw loosening continues to be a frequently cited disadvantage of this technique. This paper describes the factors involved in maintaining a stable screw joint assembly by maximizing preload on the retaining screw while minimizing joint-separating forces. Practical clinical solutions to minimize this clinical problem are suggested. Readers are cautioned to address both the occlusal and biomechanical etiologies of screw loosening.

Bone Screws↗
PubMed1997

[The modified RPI clasp design].

The modified RPI clasp was described and compared with the conventional RPI clasp in the article. The modified RPI clasp could provide adequate retention with the minimum undercut of the most distal part of abutment tooth and gain good esthetical effect. The I bar tip would disengage from the tooth and reduce or avoid torsional forces transmitted to the abutment tooth when rotation of distal-extension base occurred around the mesio-occlusal rest. Therefore, it is a new type of clasp design for the distal-extension removable partial dentures.

Dental Clasps↗
PubMed2005

[Effects of expansion fashion and expansion quantity on retention of cement-expanded composite screw post].

OBJECTIVE: To study the effects of expansion fashion and expansion quantity on retention of cement-expanded composition screw post (CECSP). METHODS: Ninety simulated tooth roots made of polymethylmethacrylate were divided into ten groups, each fashion induded five groups. The expanded plastic sheath of tricuspid valve was made with the special separated valve device and cemented and tightened up into root with the screw post at the same time by ZPC. Then the root and screw post-core system was tested by the speed of 10 mm/min on the INSTRON 4302 and the retention force was recorded. RESULTS: It appeared that the difference between different expansion fashion and different expansion quantity were significantly (P < 0.05). The retention of expansion fashion one was significantly greater than those of fashion two. The retention was best when expansion quantity was within 10%. CONCLUSION: During clinic operation, we should apply definite fashion and control the expansion quantity within 10%, and the screw post should tighten up to the bottom of prepared root.

Bone Screws↗