The etched cast metal resin-bonded (Maryland) bridge: a clinical review

Resin-bonded fixed partial denture retention: a retrospective 13-year follow-up

A total of 51 resin-bonded fixed partial dentures (RBFPDs) were inserted under controlled clinical conditions and evaluated over a period of 13 years. Three levels of survival were defined: complete survival (no debonding); functional survival (loss of retention on one occasion with rebonding of the original RBFPD); and multiple survival (loss of retention on several occasions with rebonding of the original RBFPD). The effect of the aetiology, location (anterior/posterior or maxillary/mandibulary) and number of units of the missing tooth on RBFPD survival rates were investigated. The mean survival times and confidence levels were determined for each survival category, using the Kaplan-Meier procedure. The relative risks were calculated by the Cox regression procedure. The overall complete survival level of the study population at the end of the follow-up period was 85 months +/- 13%. Rebonding the RBFPDs once increased the overall functional survival rate to 112 months +/- 10% and multiple rebonding led to a further increase to 131 months +/- 8%. The RBFPD placement under conditions of good periodontal support in which orthodontic treatment was not required, such as trauma among other factors, showed significantly higher survival rates than those placed after periodontal or orthodontic treatment. This indicates that, under both these conditions, RBFPDs may serve as long-term or semi-permanent restorations.

Clinical complications in fixed prosthodontics

The purpose of this article is to identify the incidence of complications and the most common complications associated with single crowns, fixed partial dentures, all-ceramic crowns, resin-bonded prostheses, and posts and cores. A Medline and an extensive hand search were performed on English-language publications covering the last 50 years. The searches focused on publications that contained clinical data regarding success/failure/complications. Within each type of prosthesis, raw data were combined from multiple studies and mean values calculated to determine what trends were noted in the studies. The lowest incidence of clinical complications was associated with all-ceramic crowns (8%). Posts and cores (10%) and conventional single crowns (11%) had comparable clinical complications incidences. Resin-bonded prostheses (26%) and conventional fixed partial dentures (27%) were found to have comparable clinical complications incidences. The 3 most common complications encountered with all-ceramic crowns were crown fracture (7%), loss of retention (2%), and need for endodontic treatment (1%). The 3 most common complications associated with posts and cores were post loosening (5%), root fracture (3%), and caries (2%). With single crowns, the 3 most common complications were need for endodontic treatment (3%), porcelain veneer fracture (3%), and loss of retention (2%). When fixed partial denture studies were reviewed, the 3 most commonly reported complications were caries (18% of abutments), need for endodontic treatment (11% of abutments), and loss of retention (7% of prostheses). The 3 most common complications associated with resin-bonded prostheses were prosthesis debonding (21%), tooth discoloration (18%), and caries (7%).

Analysis of depth of the microporosity in a nickel-chromium system alloy - effects of electrolytic, chemical and sandblasting etching

The present study was designed to analyse the average depth of the microporosity of a nickel-chromium (Ni-Cr) system alloy (Verabond II). The metal surface was subject to one of the following surface treatment: (i) Electrolytic etching in nitric acid 0.5 N at a current density of 250 mA cm(-2); (ii) chemical etching with CG-Etch etchant; and (iii) Sandblasting with alumina particles 50 microm. Half of the samples were polished before the surface treatments. The depth of porosity was measured through photomicrographs (500x) with a profilometer, and the data were statistically analysed using an analysis of variance (anova) followed by Tukey's test. The conclusions were (i) Differents surface treatment of the Ni-Cr system alloy lead to different depths of microporosity; (ii) The greatest depth of porosity was observed in non-polished alloy; (iii) The greatest and identical depth of microporosity was observed following electrolytic etching and chemical etching; (iv) The least and identical depth of microporosity was observed with chemical etching and sandblasting with alumina particles 50 microm, and (v) Chemical etching showed an intermediary depth.

Bond strength of dual-cured resin cements to human teeth

PURPOSE

This study evaluated the bond strength of four commercial resin luting cements to enamel and superficial dentin, using a second-generation laboratory composite.

MATERIALS AND METHODS

Forty teeth were embedded in acrylic: 20 had superficial dentin exposed; 20 had enamel exposed. Each group was divided into four subgroups (n = 5) to be bonded with Variolink II, Dual Cement, 2-bond-2, and Permalute System, using an inverted, truncated cone of pre-cured Artglass that was placed over the resin cement with a load of 2 N for 2 seconds. Specimens were stored at 37 degrees C in 100% relative humidity for 24 hours before being tested for tensile bond strength (MPa). Data were analyzed using a two-way analysis of variance. Tukey-Kramer intervals for comparisons among resin cements and bonding substrates were calculated at a .05 significance level.

RESULTS

Significant differences were found among resin cements. Variolink II had statistically higher bond strength values for both substrates than the rest of the cements evaluated. When bonding was to enamel, all failures were cohesive in the composite, and when bonding was to dentin, some adhesive failures occurred at the resin cement-dentin interface. Permalute System had higher bond strengths than 2-bond-2 and Dual Cement when bonded to enamel.

CONCLUSIONS

Variolink II and Permalute had statistically different bond strengths to enamel and dentin. Variolink II showed statistically higher values for dentin bonding than the other cements. Use of Variolink II and Permalute resulted in statistically higher bond strengths than the other two cements.

A prospective study of cantilever resin-bonded bridges: an initial report

A prospective study was undertaken in a dental teaching hospital to compare the clinical performance of cantilever resin-bonded bridges with a fixed-fixed design for the replacement of a maxillary permanent incisor. A total of 25 anterior resin-bonded bridges was placed in 24 patients. The prostheses were evaluated over 14 to 45 months. During the evaluation period only one fixed-fixed type debonded, which was subsequently rebonded successfully. There was no debond in the cantilever group. The short-term, initial findings showed that cantilever resin-bonded bridges performed as successfully as their fixed-fixed counterparts and were considered to be an acceptable form of restoration.

Effects of adhesive fixed prosthesis retainer design on resultant resin luting agent thickness

STATEMENT OF PROBLEM

Resin cement thickness may influence the success or otherwise of adhesive fixed prostheses and needs to be quantified for future stress analyses.

PURPOSE

This study evaluated the effect of different complexities of retainer preparation design on resultant resin lute thickness.

MATERIAL AND METHODS

Five retainer designs were evaluated for resin luting thickness (Panavia Ex) after cementation to appropriately selected natural teeth as follows: (1) flat plate retainer; mandibular canine; (2) occlusal rests, mandibular premolar; (3) occlusal rests, proximal grooves, mandibular premolar; (4) modified three-quarter crown, mandibular premolar; and (5) occlusal strut, maxillary premolar. Five samples of each design were prepared in vitro. A mesiodistal and a buccolingual section were obtained from each sample with a diamond saw. Measurements were carried out on the fluorescent cement lute with a confocal microscope. Mean resin thickness and cervical resin thickness were analyzed with analysis of variance and Tukey tests.

RESULTS

Resin thickness (micron) for each of the retainer designs were as follows (mean +/- SD): design 1, 58 +/- 40; design 2, 67 +/- 42; design 3, 80 +/- 28; design 4, 87 +/- 15; and design 5, 85 +/- 29. There were no significant differences among the designs (mean global value 75.4). The three-quarter crown (design 4) had a significantly wider cervical resin thickness (P < or = .01) than designs 1, 2, and 3.

Effect of convergence angle on retention of resin-bonded retainers cemented with resinous cements

STATEMENT OF PROBLEM

Poor retention is a common cause of failure for resin-bonded restorations.

PURPOSE

This study evaluated the effect of the convergence angle of tooth preparations on retention of resin-bonded restorations, luted with adhesive and conventional resinous cements.

MATERIAL AND METHODS

A total of 80 posterior retainers with four different tooth preparation angles were cemented with two different resinous cements, and retentive strength was measured.

RESULTS

The results indicated that (1) increased tapering of tooth preparations resulted in loss of retention and this variable was statistically significant for both cements used when convergence angles exceeded 10 degrees and (2) sandblasted nickel-chromium retainers, combined with adhesive resins, should provide sufficient retention for posterior resin-bonded fixed partial dentures.

Resin-bonded fixed partial dentures: a review of three decades of progress

The resin-bonded fixed partial denture has undergone significant changes in design, materials and tooth preparation since its development in 1973. The selection of resin cement and micromechanical retention have closely paralleled alloy-resin-bonding research. Despite impressive in vitro research results, only 74 percent of the prostheses are still functional at the end of four years. Understanding the limitations, indications and design of resin-bonded fixed partial dentures will result in improved longevity and patient satisfaction.

Clinical performance of resin-retained fixed partial dentures bonded with a chemically active luting cement

A clinical study was undertaken to review resin-retained fixed partial dentures bonded with a chemically active luting cement during a 4-year period. One hundred thirty-seven fixed partial dentures were reviewed of which five had failed because of a nonbonding failure (esthetics, trauma, fracture) and 47 (36%) had failed after a bonding failure, of which 72% were rebonded. The mean time of failure was 10.9 months (SD 9.8). The failure rate appeared to be affected by position, use of a rubber dam, and the fixed partial denture design, although no one factor reached conventional statistical significance.

Tensile fatigue of 4-META cement bonding three base metal alloys to enamel and comparison to other resin cements

The tensile median fatigue limits and fracture mode of 4-META cement were evaluated after bonding Ni-Cr, Ni-Cr-Be, and Co-Cr alloys to enamel. Alloy surfaces, 6 mm in diameter, were grit blasted with 50 microns Al2O3 and cemented to etched bovine enamel under a 2 kg load. Samples were cycled in tension to failure or 10(6) cycles at 5 Hz in Ringer's solution at 37 degrees C. Two-point strategy was used to determine median fatigue limits (S50). Fracture modes were evaluated by SEM on samples failing before 10(6) cycles. Results indicated differences between all sample groups where S50 (Ni-Cr-Be) > S50 (Co-Cr) > S50 (Ni-Cr). Failure analysis revealed mixed cohesive fractures near both interfaces with small areas of delamination within the cement. Comparison to reported median fatigue limits of two commercially available cements were discussed.

Chemical etching solutions for creating micromechanical retention in resin-bonded retainers

This study introduced three chemical etching solutions capable of producing micromechanical retention in nickel-chromium and nickel-chromium-beryllium alloys used for resin-bonded retainers. The effectiveness of the chemical etching solutions was evaluated with tensile strength tests and photographs at various magnifications with a scanning electron microscope. Chemical etching with the CG-Etch solution produced suitable and uniform microretention whereas the other solutions were not effective on all metal alloys. Significant differences (p < 0.05) relating to tensile bond strengths were noted. The CG-Etch solution gave the highest mean bond strength compared with solutions II, III, and control groups.

A multi-practice clinical study on posterior resin-bonded bridges: a 2.5-year interim report

A clinical trial of 201 posterior resin-bonded bridges (PRBBs) was conducted partially in a University clinic and partially in general dental practices, for study of the influence of some experimental variables on the survival of these restorations. This report contains the results of an interim analysis which was done after 2.5 years' follow-up. No significant differences were found among the bonding systems used to adhere the PRBBs (Clearfil F2/etching, Panavia EX/sandblasting, and Microfill Pontic C/silicate-coating), or among the different preparation forms. PRBBs made in general dental practices were as retentive as those made in the University clinic. The "location" factor was found to be highly significant (p = 0.0001). The survival rates were 81% for maxillary PRBBs and 56% for mandibular PRBBs.

Tensile fatigue of two composite cements bonding three base metal alloys to bovine enamel

Tensile fatigue endurance limits were determined for three base metals (Ni-Cr, Ni-Cr-Be, and Co-Cr) bonded to bovine enamel using two composite cements: a Bis-GMA/phosphate ester composite cement which relies on a sand-blasted metal surface, and a Bis-GMA composite luting cement which relies on electrolytically etched metal surfaces. Samples were tested to failure or to 10(6) cycles at 5 hz in Ringer's solution at 37 degrees C, and endurance limits were determined using a two-point test strategy. SEM evaluation was performed on fractured samples to determine failure mode. Statistical analysis of the results showed no difference between cements when using Ni-Cr-Be; however when using Co-Cr, the Bis-GMA/phosphate ester cement produced greater values than the Bis-GMA cement that relied on electrolytical etching. The opposite result occurred when a Ni-Cr alloy was tested with both cements. Evaluation of the results for each cement with the three different alloys showed statistical significant differences. SEM fracture analysis revealed a mixed failure pattern with apparent adhesive fracture from both the composite-enamel and composite-metal interfaces and cohesive failure throughout the cement.

An analysis of multiple failures of resin-bonded bridges

A clinical trial involving 203 resin-bonded bridges (RBBs) was undertaken to investigate the influence of several variables on the survival of these prostheses. This article presents the experiences with rebonded and replacement RBBs after failure of the originally bonded RBBs. A total of 62 dislodged and rebonded RBBs was included in this study and evaluated using Kaplan-Meier estimates. Rebonded RBBs that dislodged for a second time were replaced by another type of RBB ('replacement' RBBs, n = 32). The study revealed that rebonded RBBs were more susceptible to dislodgement than originally bonded RBBs. Fifty per cent survival was reached 2.1 years after rebonding. The sooner the first dislodgement occurred, the lower the retention rate of the rebonded RBB (PH-model, beta = 0.78, P = 0.02). Also some failure characteristics were evaluated. Failure characteristics (i.e. fracture site and partial versus complete dislodgement) of first and second dislodgement were not correlated (Chi-square, P values > 0.25). The survival of 'replacement' RBBs was significantly better than the survival of multiply failure RBBs (median survivals respectively 1.6 years and 1.0 year, P = 0.03). From the results of this study it may be concluded that the survival rates of rebonded and replacement RBBs were unacceptable.

A seven-and-a-half-year survival study of resin-bonded bridges

A clinical trial, concerning 203 resin-bonded bridges (RBBs), was performed for investigation of the influence of retainer-type and cementation materials on the survival of these restorations. The survival rates after a 7.5-year follow-up were 75% for anterior RBBs and 44% for posterior bridges. Etched metal RBBs (E-bridges) were significantly more retentive than perforated RBBs (P-bridges); the survival rates were 78% and 63%, respectively. With respect to the cementation materials, Clearfil F, in combination with E-bridges, had the best overall survival (89%, anterior and posterior). Maxillary anterior RBBs were more susceptible to failure than mandibular anterior RBBs.

Resin-bonded prostheses for posterior teeth

This study evaluated fixed partial dentures bonded with resin to dentin on posterior teeth with minimal tooth preparation. The patients included were missing at least one premolar or first molar. The abutment teeth next to the modification spaces were moderately restored with MOD or class II restorations on most of the teeth. A total of 20 patients with 23 fixed partial dentures were included in the study. After removal of existing restorations, the abutment teeth were prepared to eliminate undercuts on the perimeter of the preparations. Undercut areas within the preparation were not filled but were blocked out later in the laboratory. The fixed partial dentures employed inlays as retainers for a metal ceramic pontic. The metal framework was cast in a high noble gold alloy. The areas of the retainers to be bonded were treated with the Kulzer Silicoater method. Immediately before cementation, enamel was etched and exposed dentin was treated with Gluma. Kerr's resin bonded bridge cement was used for cementation. Patients were recalled after periods of 1 week, 1 month, 6 months, 1 year, 2 years, and 4 years for evaluation. None of the restorations lost retention and no major adverse effects were observed in the 4-year follow-up period.

Performance of 400 adhesive bridges fitted in a restorative dentistry department

The purpose was to present a descriptive report of the clinical performance of adhesive bridges fitted in a university department of restorative dentistry. The case records of 400 consecutive adhesive bridges fitted between November 1984 and June 1989 in the School of Clinical Dentistry, Queen's University, Belfast were reviewed. The majority of the bridges (66 per cent) were of a fixed-fixed Maryland design; the remainder were Maryland cantilevers (18 per cent), hybrids, i.e. Maryland cantilevers which slotted into conventional units (8 per cent), and Rochette bridges (6 per cent). The mean duration of clinical service at review was 2.7 years. One hundred (25 per cent) of the bridges debonded on at least one occasion. Of the bridges which debonded the average number of debonds was 1.7, with the first debond happening on average 10.7 months after placement (range 1-42 months). Fifty-seven (14 per cent) debonded on one occasion only; 25 (6 per cent) debonded twice and 18 (5 per cent) debonded on three or four occasions. The length of clinical service was a significant factor in relation to debonding. A lower proportion of posterior than anterior bridges debonded and cantilevered and hybrid designs performed well. It is concluded that this investigation confirms the efficacy of resin-bonded bridgework used to replace both anterior and posterior teeth.

Resin-bonded fixed partial dentures: a recall study

A clinical recall program was initiated at the University of Minnesota to evaluate the longevity and factors affecting longevity of resin-bonded fixed partial dentures (FPDs). Of the 49 resin-bonded FPDs evaluated in the clinic, 43 were acid-etched metal, resin-bonded FPDs, four were combinations of resin-bonded and conventional FPDs, and two were composite resin pontics. None of the combination FPDs and one of the two composite resin pontics were judged as failed at the examination. Of the 43 acid-etched metal resin-bonded FPDs, 15 were found to be debonded (failure rate = 34.9%). The average length of service for the 43 FPDs was 47.3 months. The average time of placement to debondment was 33 months for the 15 debonded FPDs. The failure rate for maxillary FPDs and FPDs with two retainers were significantly lower than the failure rate for mandibular FPDs and FPDs with more than two retainers (p greater than 0.05). The clinical significance of the present study was discussed.

An analysis of clinical studies on resin-bonded bridges

Many clinical data on resin-bonded bridges (RBBs) have been published in the last ten years. The survival rates vary widely, and the conclusions are sometimes conflicting. A method of combining the results of different studies in order to draw conclusions about the effectiveness of therapeutic concepts is meta-analysis. The aims of the meta-analysis in this study were: (1) to assess an "overall" survival ratio for RBBs and (2) to explore relationships between potential success factors and reported survival times. About 60 publications with clinical data on RBBs were reviewed. Following a number of inclusion criteria (information adequate to calculate or assess survival rates, as well as adequate information about the patients, the designs, and types of RBBs), 16 different samples were used for this meta-analysis. A weighted multiple-regression analysis revealed no significant effects of "type of retention" and "location" on the survival percentages. Kaplan-Meier estimates were used to assess overall survival in a secondary analysis with the data from all 16 samples (n = 1598). The overall survivals were: one year, 89 +/- 1%; two years, 84 +/- 1%; three years, 80 +/- 1%; and four years, 74 +/- 2%.