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PubMed1995

Prospective investigation of the single-crystal sapphire endosteal dental implant in humans: ten-year results.

This study conducted a longitudinal prospective clinical study of the single-crystal sapphire (Al2O3) cylindrical screw-shaped endosteal dental implant, and attempted to establish clinical parameters to evaluate implant success or failure. Twenty-eight mandibular implants (17 patients) were placed. After six weeks' healing, 23 implants in 15 patients served as distal abutments for fixed prostheses (baseline). Implants were evaluated for bleeding index, crevicular fluid volume index, plaque accumulation index, radiographic index, mobility index, and patient comfort. Any implant failing in three of these criteria or implants removed were judged as failures. After 10 years, of the 21 baseline implants recalled (two implants were lost to recall), 17 were fully functional, for an 81% success rate. The use of qualitative and quantitative clinical evaluation parameters as utilized in this study appears to be important and useful in assessments of the clinical serviceability of dental implants. These parameters can be used in human clinical trials as well as in experimental animal studies.

Aluminum Oxide↗
PubMedDate not supplied

The spline implant: design, engineering, and evaluation.

The design and engineering characteristics of the Spline dental implant were investigated. Compressive strength, rotational movement, resistance to cyclic loading and torsional strength were evaluated. The results of the mechanical test indicated that this implant/abutment complex is mechanically stable, has minimal rotational movement, improved resistance to screw loosening, and good interface fidelity. The data for the new design are compared with published data for other implant/abutment connections.

Compressive Strength↗
PubMed1998

The implant quality scale: a clinical assessment of the health--disease continuum.

Implant success is as difficult to describe as the success criteria required for a tooth. A range from health to disease exists in both conditions. The primary criteria for assessing implant quality are pain and mobility. The presence of either one greatly compromises the implant, and removal is usually indicated. Probing depths may be related to the presence of local disease or pre-existing tissue thickness before the implant was inserted. An increasing probing depth is more diagnostic and signifies bone loss, gingival hyperplasia or hypertrophy. Bone loss is usually evaluated best with probing rather than with radiographs. The most common cause of bone loss during the first few years of function are exaggerated factors of stress. The bleeding index is easily observed and indicates inflammation of the gingiva. However, implant health status is not as related to sulcular inflammation as would be the case for a natural tooth. Implant failure is easier to describe and may consist of a variety of factors. Any pain, vertical mobility, uncontrolled progressive bone loss, and/or generalized periradiolucency warrant implant removal. Implant quality factors were established by James and modified by Misch into an implant quality scale which not only assesses the implant health-disease continuum, but relates treatment and prognosis to the existing conditions.

Alveolar Bone Loss↗
PubMed2002

Bond strengths of five tapered root posts regarding the post surface.

The advantage of tapered passive root posts is their homogenous force transmission without creating stress peaks on the root surface because of their anatomical root form. However, their expected retentive strengths are low compared with the other post systems. The objective of this in vitro study was to determine the retentive strengths of five tapered post systems from different manufacturers using tensile tests. For this purpose, all posts were cemented with zinc phosphate cement (Tenet) into the roots of 50 intact anterior teeth according to the manufacturer's instructions for each system. The contact surface area between the root canal wall and the post was taken into account in the calculations in order to obtain comparable results for different post configurations. The highest bond strength values were achieved for the Erlangen post system (10.8 N mm(-2)) and MP Pirec post system (10 N mm(-2)). These values were more than three times those of the Velva-Post (3.2 N mm(-2)) and the Cylindro-Conical system (3.5 N mm(-2)) and five times more than those of the Dr Mooser post system (1.7 N mm(-2)). The bond strength values of the Erlangen post system, Cylindro-Conical system and Dr Mooser post system showed statistically significant differences compared with the other groups. The results of this study indicated that the bond strengths of tapered posts were not only affected by the contact surface but also by the taper angle, shape of the post system, the width of the cement joint, surface roughness of the posts as well as the form of the canal wall. In clinical practice, in case of choosing tapered posts with similar shapes, retention may still vary because of other factors.

Dental Bonding↗
PubMed2004

Retrofitting a cast dowel-core on salvaged dental implants.

Dental implant screw fracture involves attempting to retrieve the screw fragment or, as an alternative, attempting to salvage the dental implant. Circumstances that do not allow for screw retrieval require a solution in which the internal configuration of the dental implant can provide for a custom direct dowel fabrication. The proposed technique is to retrofit the fabrication of a custom cast dowel-core and provisional use of a direct procedure, which provides accuracy of fit, retention, and ease of production.

Crowns↗
PubMed1994

The effect of endodontic access cavity preparation and subsequent restorative procedures on incisor crown retention.

Endodontic treatment often will require access through existing crowns. This study was undertaken to determine whether endodontic access cavity preparation affected the retention of crowns in anterior teeth and then to determine whether this retention can be regained by amalgam or post-retained amalgam restorations. Twenty extracted human incisors were mounted in acrylic blocks and prepared for crowns. Metal copings were fabricated and cemented with zinc phosphate cement and the forces required to displace the copings after various procedures were measured with a tensile testing machine. Retention values for all stages were compared with the initial retentive value for each coping without an access cavity which was set at 100 per cent. Group one specimens had the following means: copings with access cavity, 85.64 +/- 28.65 per cent of the initial values; amalgam flush with lingual dentine, 95.81 +/- 36.2 per cent; amalgam flush with coping, 114.89 +/- 34.5 per cent. Group two means were: copings with access cavity, 89.95 +/- 21.42 per cent; posts and amalgam, 177.37 +/- 77.5 per cent. Statistical analysis with the two sample t test showed that retention with post-retained amalgam restorations showed significantly higher values when compared with access cavities without restorations (p < 0.05). Retention values for post-retained restorations were significantly different from those just using amalgam. This study demonstrated that endodontic access cavities reduced the retention of the crowns, and subsequent restoration with amalgam or a post can regain the retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Crowns↗
PubMed2006

Study of the colors and retention of over-the-counter cosmetic veneers.

The purpose of this study was to observe the tooth colors and retention of a cosmetic veneer Fiche Pearl On containing shellac and five experimental formulations containing benzoin gum and ethyl cellulose. Tooth color was measured with a spectrophotometer before and after application of the veneers to the buccal or labial surface of experimental teeth. Through both in vitro and in vivo studies, the retention rates of veneers were assessed. In terms of color difference (deltaE*ab) between before and after veneer application, it ranged from 4.3 (Fiche Pearl On) to 15.0 (experimental formulation White Plus). In terms of retention rate, in vitro test found the retention rate of experimental formulation White Plus was significantly higher than that of Fiche Pearl On. In in vivo test where subjects were permitted to drink water and tea, it was found that the retention rate after two hours ranged from 94.0 to 98.5%. In conclusion, teeth applied with the experimental cosmetic veneer formulations showed better color and retention than teeth with Fiche.

Analysis of Variance↗
PubMed2000

Restoration of endodontically treated tooth containing wide or flared canal.

There has been much anecdotal information and misinformation disseminated regarding the restoration of endodontically treated teeth, which has comprised the foundation for our restorative protocol. In the past, it was considered appropriate to place a cast post and core in every pulpless tooth without regard to the amount of remaining supportive tooth structure present. Recent developments in available ceramics, greater cosmetic demands by patients, and the advent of adhesive bonding techniques have caused clinicians to reevaluate their restorative protocol. This article reviews the current literature with regard to restoration of the endodontically treated tooth and presents a method for restoration and reinforcement using a combination of polyethylene ribbon and a prefabricated fiber post to create a post and core that is retentive, supportive, cosmetic and able to impart reinforcement to a structurally compromised root.

Composite Resins↗
PubMed2003

Effect of circumferential undercut placement in the root canal wall on the retention of a tapered post in large and small root canals.

OBJECTIVES: This study examined the influence of root canal space and circumferential undercut placement in the dentine wall on the retention of a prefabricated Root Keeper post. METHODS: Twenty-four extracted single-rooted teeth, having narrow root canal spaces, were decoronated, treated endodontically, and then centrally embedded in resin blocks. All canal spaces were prepared with a no. 2 Peeso reamer to an 8mm depth, and half the specimens were successively treated with a no. 3 Peeso to depths of 5 and 8mm for the small canal group (SC) and large canal group (LC), respectively. An L-type keeper post (Aichi Steel Co.) was luted to each canal with resin cement. The assembly was thermocycled 2000 times (4-60 degrees C), and post retention was measured. Afterwards the dislodged post with the intact structure was sandblasted, and the canal was cleaned and slightly undercut using an inverted cone bur. Six treated posts were recemented for both grooved large canal (GLC) and grooved small canal (GSC) groups, and the repaired retentive strengths were measured. RESULTS: Keeper posts cemented in SC (84.26+/-31.85N) showed better (p<0.05) retention than those cemented in LC (41.92+/-22.36N). Interestingly, the repaired strengths of the recemented post increased in both GSC (104.29+/-11.89N) and GLC (96.65+/-6.91N). All posts, except for one in the GLC, failed at the keeper-post joint. CONCLUSIONS: Prefabricated Root Keeper posts had lower retentive strength in roots with a large canal space. Placement of a circumferential undercut in the root canal wall significantly enhanced the retention of the short tapered posts.

Cementation↗
PubMed1993

One-year clinical evaluation of three dentine bonding agents.

One hundred and twenty-five composite restorations were placed in non-undercut, non-enamel-etched Class V abrasion lesions in 20 patients using the dentine bonding agents Scotchbond 2, Tripton, and Prisma Universal Bond 2. Patients were recalled at approximately 3 months, 6 months, and 1 year. After 1 year the cumulative per cent survival of restorations was Scotchbond 2, 8 per cent; Scotchbond 2 with dentine roughening, 16 per cent; Tripton, 16 per cent; Prisma Universal Bond 2, 75 per cent.

Age Factors↗
PubMed1993

Recent developments in restorative dental ceramics.

Since the introduction of porcelain jacket crowns in the early 1900s, dental ceramics have been praised for their esthetic appearance. But there's more to consider: other benefits, longevity, limitations. This review addresses major developments in modern dental ceramics and metal-ceramics.

Aluminum Oxide↗
PubMed1998

A review of nondestructive test methods and their application to measure the stability and osseointegration of bone anchored endosseous implants.

Threaded and cylindrical metallic endosseous implants are being used increasingly in cranio-facial, dental, and orthopedic surgery. There is a significant need for the development of quantitative noninvasive test methods to measure implant stability and success. Such success can be quantified by measurements of the stiffness and damping of an implant in the surrounding bone, and also the height of the marginal bone around an implant. In the case of a failing implant, the bone around it is replaced by fibrous tissue, and in the case of an overloaded implant the bone height around the implant falls. Nondestructive test methods have been applied to the testing of implant and tooth mobility, and commonly these have used transient or steady-state test methods. Transient methods entail tapping an implant, measuring its response and then performing a Fast Fourier Transform to resolve the fundamental frequencies. Steady-state methods measure the frequency response of a system using a swept frequency wave form. A number of dedicated electronic instruments have been designed to perform these tasks, and this article discusses their applications, accuracy, and value as clinical diagnostic instruments.

Biocompatible Materials↗
PubMed1993

Analysis of performance of root-form endosseous implants placed in the maxillary sinus.

To evaluate the long-term effect on metal-bone interface of the perforation of the maxillary antral floor by root-form titanium implants, a study was undertaken in five mature Macaca fascicularis monkeys. One root-form titanium implant was placed bilaterally in the maxillary sinus perforating the sinus 5 mm and a second implant was placed completely in bone tissue. The protruding implant in the right antrum was grafted with autogenous cancellous bone and porous bone mineral (Bio-Oss) and the contralateral antral implant protruding in the antrum was left without grafting. The bilateral implants were used to support "free-standing" fixed prostheses, which were in full function for 14 months, during which time there was excellent clinical function and no mobility of the implants. Histomorphometric analysis of specimens revealed that there was no difference in the trabecular pattern or the amount of calcified matrix vs. marrow vascular spaces along the titanium implant interface. New reparative bone partially restored the osseous surface along the implant on the ungrafted side. Implants in the grafted antrum demonstrated bone regeneration over the implant surface ranging from 2 cm to complete regeneration. Histomorphometric analysis revealed the peri-implant bone to contain some particles of the Bio-Oss, although most of the implant bone interface exhibited only vital bone and marrow vascular spaces. The study indicates that the protrusion of implants maximally into the sinus floor does not necessarily require a bone graft to produce functional abutments for fixed prostheses and that implants can function well with 5 mm of protrusion into the antrum with excellent bone-metal interface.

Animals↗
PubMed1992

Solving the problem of violated intermaxillary space caused by poor pre-planning and improper placement of endosseous implants: a case report.

Every dental implant patient needs thorough evaluation and pre-surgical planning. It is imperative for the practitioner to have absolute knowledge of the implant system to be used. Nevertheless, sometimes we find ourselves in very difficult, almost unrestorable, situations. Often, we cannot rely on the implant manufacturers, and we have to be ready to customize some parts in order to solve difficult clinical situations. This case report shows how customized magnet keepers were fabricated by use of plastic IME's as casting patterns in order to solve the problem of violated intermaxillary space.

Dental Alloys↗
PubMed1992

A retrospective evaluation of endosseous titanium implants in the partially edentulous patient.

Partial edentulism in 34 patients was consecutively treated using the Brånemark osseointegration technique. A total of 102 implants was tested for mobility, signs and symptoms of infection, and radiographic bone levels. All patients had at least a 6-month follow-up of prosthesis function (mean 22.5 months). An overall success rate of 88.2% was observed. Twenty-five of 28 maxillary implants and 65 of 74 mandibular implants were successfully placed and restored. Twelve failures were observed; 7 were not integrated at the time of stage 2 surgery while 5 occurred after prosthetic reconstruction. The results of this study suggest that the Brånemark osseointegration procedure can be used to treat partially edentulous patients with a high degree of success.

Adult↗
PubMed2005

Short-term retentive values of zirconium oxide posts cemented with glass ionomer and resin cement: an in vitro study and a case report.

OBJECTIVE: This paper presents the results of an investigation focusing on the retention of all-ceramic posts. The aim of the study was to evaluate the influence of two luting agents--a glass-ionomer cement (Ketac Cem) and a resin cement (Panavia F)--on the retention of a prefabricated ceramic post (Cerapost) after different pretreatment techniques in vitro. METHOD AND MATERIALS: Forty freshly extracted incisors and canines were treated endodontically. The root canals were filled with laterally condensed gutta-percha and sealer. The teeth were assigned to 1 of 4 groups, each containing 10 specimens: sandblasted/nonsandblasted post cemented with glass-ionomer cement and sandblasted/nonsandblasted post cemented with resin cement. Tensile tests were carried out. The specimens were also quantitatively analyzed under a scanning electron microscope. RESULTS: The retentive strengths of posts, sandblasted and nonsandblasted, and cemented with Panavia F resin cement, were significantly increased as compared to those cemented with Ketac Cem. CONCLUSION: Both the luting agent and the post-surface pretreatment had a significant influence on the retention of the ceramic post.

Adult↗
PubMed1977

Implants for fixed and removable prostheses.

For those individuals whose oral anatomy contraindicates the use of endosteal implants, there still remains a viable alternative to conventional removable dentures. Both maxillary and mandibular implant dentures of a subperiosteal design will provide a stable implant and a retentive restorative prosthesis. The patient is free from the oral gymnastics required to manipulate such appliances and in the maxilla the dentist is able to eliminate all palatal coverage without compromising the retention of the bridge. The lower subperiosteal implant and the pterygoid extension implant discussed both obtain their stability from accurate fit of the implant substructure to the bone. The implant first becomes more retentive when the periosteum tenaciously reattaches itself to the bone and in turn secures the implant in position (Fig. 13). The restorative procedures follow sound prosthetic prinicples with particular attention on avoiding any impingement of the underlying tissue areas. Implant dentures have truly provided patients a means of exploring alternative treatment modalities other than conventional removable dentures. Literally thousands of patients today are living testimony to the accomplishments of oral implantology when pursued as an exacting science prescribed by colleagues experienced in this revolutionary dental discipline.

Dental Implantation↗
PubMed1993

Comparison of the retentive properties of two hollow-tube post systems to those of a solid post design.

The retention of a post in a root is critical for the successful restoration of an endodontically treated tooth. This study compared the retention of two hollow-tube post designs (Access post and World post) cemented with zinc phosphate cement or a titanium-reinforced composite resin cement (Flexi-Flow cement with titanium) with that of the control Para-Post system, a solid post design cemented with zinc phosphate cement. The experiment was divided into 11 groups of 10 samples. Retentive values were measured with a universal testing machine and the data were recorded in pounds. A one-way analysis of variance was computed and included Duncan's multiple comparisons test, Tukey's Student range test, and Dunnett's test. Duncan's multiple comparison test and Tukey's test were inconclusive. Only Dunnett's test revealed a significant difference between group 5, Access post, grooved dentin with Flexi-Flow cement with titanium (mean of 89.7 lb), and the control, group 11, Para-Post dowel cemented with zinc phosphate cement (mean of 61.3 lb). All other groups exhibited similar results with retentive values that ranged from 62 to 76 lb.

Acid Etching, Dental↗