Performance of 400 adhesive bridges fitted in a restorative dentistry department

Layer structure and load-bearing properties of fibre reinforced composite beam used in cantilever fixed dental prostheses

This study evaluates the effect of fiber reinforcement quantity and position on fracture load of fixed dental prostheses specimens with different fibre reinforced composite (FRC)/ particulate filler composite (PFC) ratio in a cantilever beam test. Three types of specimen structures where made: Specimens with FRC, PFC, or with a combination of both. Specimen's size was 2.0×2.0×25 mm³ and the thicknesses of the FRC layers were 0, 0.5, 1.0, 1.5 and 2.0 mm. The layers of FRC were placed at the top or at the bottom. Eight groups of specimens were evaluated (n=15/group). The test specimens were statically-loaded until fracture. The fracture loads were linearly dependent on the quantity of the FRC reinforcement when placed at the top (R²=0.941) and bottom (R²=0.896) of the specimens. ANOVA revealed that reinforcement position on the tension side and higher FRC reinforcement volume in the test specimens had positive effect to load bearing capacity (p<0.001).

Influence of the amount of tooth surface preparation on the shear bond strength of zirconia cantilever single-retainer resin-bonded fixed partial denture

PURPOSE

Conventional resin-bonded fixed partial dentures (RBFPDs) are usually made with a two-retainer design. Unlike conventional RBFPDs, cantilever resin-bonded fixed partial dentures (Cantilever RBFPDs) are, for their part, made with a single-retainer design. The aim of this study was to compare the effect of tooth surface preparation on the bond strength of zirconia cantilever single-retainer RBFPDs. The objective is to evaluate the shear bond strength of these single-retainer RBFPDs bonded on 3 different amount of tooth surface preparation.

MATERIALS AND METHODS

Thirty extracted bovine incisors were categorized to 3 groups (n=10), with different amounts of tooth surface preparations. Teeth were restored with single-retainer RBFPDs with different retainer surfaces: large retainer of 32 mm²; medium retainer of 22 mm²; no retainer and only a proximal connecting box of 12 mm². All RBFPDs were made of zirconia and were bonded using an adhesive system without adhesive capacity. Shear forces were applied to these restorations until debonding.

RESULTS

Mean shear bond strength values for the groups I, II, and II were 2.39±0.53 MPa, 3.13±0.69 MPa, and 5.40±0.96 MPa, respectively. Statistical analyses were performed using a one-way ANOVA test with Bonferroni post-hoc test, at a significance level of 0.001. Failure modes were observed and showed a 100% adhesive fracture.

CONCLUSION

It can be concluded that the preparation of large tooth surface preparation might be irrelevant. For zirconia single-retainer RBFPD, only the preparation of a proximal connecting box seems to be a reliable and minimally invasive approach. The differences are statistically significant.

The Use of All-Ceramic Resin-Bonded Bridges in the Anterior Aesthetic Zone

For several years, all-ceramic resin-bonded bridges (RBBs) have been considered an aesthetic treatment option for the replacement of missing teeth in the anterior region. With continued developments in technology, various different ceramic materials have been used to fabricate all-ceramic RBBs including zirconia, glass-reinforced, alumina-based ceramics, and lithium disilicate glass ceramics. The aim of this article is to provide an overview of all-ceramic RBBs, the advantages and disadvantages associated with these prostheses, as well as to demonstrate their application in replacing missing anterior teeth. Clinical relevance: To present the current literature and clinical application of all-ceramic resin-bonded bridges for replacing missing anterior teeth.

A fixed movable resin-bonded fixed dental prosthesis--A 16 years clinical report

PATIENTS

This report describes the case of a 48-year-old female patient who initially received a 4-unit fixed-fixed (FF) resin-bonded fixed dental prosthesis (RBFDP) for replacement of mandibular left second premolar and first molar. Twenty-one months later, debond of the RBFDP was found at one of retainers. A new fixed-movable RBFDPs with a modified non-rigid connector as well as increased resistance form features was placed and successfully retained at the 16-year clinical review.

DISCUSSION

RBFDPs are a conservative tooth replacement option that requires minimum tooth preparation and retention by a resin cement to etched enamel. However debonding is the most frequently seen complication and has been attributed to the relative movement between abutment teeth during function that stress the bonding interface. This case report highlights the use of modified non-rigid connector which allows relative movement between abutment teeth and therefore a reduced stress on the bonding interface.

CONCLUSION

It is proposed that the use of modified non-rigid connectors that allow independent movement between the abutment teeth during function was responsible for the long term clinical success of fixed-movable RBFDPs.

Replacement of a Congenitally Missing Maxillary Incisor by Implant Supported Prosthesis

Maxillary central incisors have the least incidence of congenital absence. When it does happen, the patient may present with over retained deciduous centrals or the contralateral central may have drifted into the available space presenting as generalised anterior spacing with loss of midline. In such cases a multi-disciplinary approach may be required with orthodontic treatment to re-organise the space available in order to rehabilitate the patient with a fixed prosthesis. This case report presents the treatment of a patient with congenitally missing maxillary left central incisor using dental implant with angulated abutment after orthodontic correction and stabilization of the remaining maxillary anteriors.

Repair of a multiple implant-supported fixed superstructure with a metal-ceramic resin-bonded fixed partial denture: a clinical report

Even in the case of implant loss, replacement of the implant and refabrication of the superstructure are often sufficient, as long as the bone and soft tissue are in good condition. However, if implant loss accompanied by serious bone resorption occurs with a fixed implant superstructure supported by multiple implants, it is very difficult to treat. This clinical report describes the process by which multiple implant-supported fixed metal ceramic restorations were repaired with a metal ceramic resin-bonded fixed partial denture without complete refabrication after removal of one of the implants due to severe bone resorption. The 3-year follow-up indicated excellent serviceability and a well-satisfied patient.

Minimally invasive preparation and design of a cantilevered, all-ceramic, resin-bonded, fixed partial denture in the esthetic zone: a case report and descriptive review

Resin-bonded, fixed partial dentures have the potential to offer a minimally invasive, fixed-prosthetic approach to tooth replacement in patients who may not be candidates for implant therapy. However, traditional preparation protocols often recommend extensive preparation designs on two abutment teeth, thereby potentially compromising the long-term health of the adjacent abutments and often resulting in unilateral debonding of one of the retainers in the long term. In light of advances in high-strength ceramic systems capable of being reliably bonded to tooth structure and offering improved esthetic outcomes, as well as clinical and case-series research demonstrating improved survivability of cantilevered resin-bonded fixed partial dentures, new preparation designs and methodologies can be advocated. The following case report demonstrates the clinical application of sonoabrasion, coupled with a dental operating microscope, to minimally prepare a single abutment for a cantilevered, all-ceramic resin-bonded fixed partial denture. Relevant historic and contemporary literature regarding double versus single-retainer resin-bonded fixed partial dentures are reviewed, as well as clinical conditions that are most favorable for such restorations to have an optimal long-term prognosis.

CLINICAL SIGNIFICANCE

If appropriate clinical conditions exist, a cantilevered, all-ceramic, resin-bonded, fixed partial denture may be the most conservative means of tooth replacement in a patient who is not a candidate for an endosseous implant.

Immediate tooth replacement using fiber-reinforced composite and natural tooth pontic

The loss and replacement of anterior maxillary teeth poses several challenges. In patients refusing implant surgery, when minimal tooth reduction is desired, a fiber-reinforced composite fixed-partial denture may be used as a conservative alternative to a conventional fixed-partial denture for replacement of a single missing tooth. This article describes a clinical technique and six-year follow-up. The patient presented with a missing maxillary central incisor due to localized juvenile periodontitis. The abutment teeth were clinically stable. The advantage of supragingival margins and minimal tooth structure removal made the bonded bridge with a natural tooth pontic a viable procedure for this compromised restorative situation.

The clinical performance of hybrid bridges delivered by undergraduate dental students: a retrospective study

The aim of this study was to retrospectively analyse the clinical performance of hybrid bridges and their effect on periodontal health. All the bridges in this study were delivered by undergraduate dental students at the University Dental School and Hospital Cork. The recall protocol took the form of a questionnaire and a full clinical examination of the abutments, retainers and contra lateral control teeth. In all, 22 patients with 25 bridges were examined. The periodontal response was generally favourable and soft tissue alteration was minimal. The outcome of the performance hybrid bridges is not encouraging, as 32% (8) of the bridges failed and 68% (17) were in service with a mean duration of clinical service of 48 months.

Survival of resin-bonded bridgework provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors

OBJECTIVE

To analyse the clinical performance and factors influencing the survival of resin-bonded bridgework provided for hypodontia patients with missing maxillary lateral incisors, following orthodontic treatment to open, maintain or redistribute the missing tooth space.

DESIGN

A retrospective analysis of patients treated at a single centre using case notes with all patients invited for review to corroborate findings.

SETTING

Departments of Orthodontics, Child Dental Health and Restorative Dentistry, Newcastle upon Tyne Dental Hospital and School.

SUBJECTS AND METHODS

Between 1989-2000, 59 suitable hypodontia patients were identified of whom 45 had complete records. For these patients 73 resin-bonded bridges (RBBs) were provided. Following invitation, 24 patients attended for a review appointment. The survival of the RBBs, grade of operator providing treatment, duration of post-orthodontic retention, the influence of design, presence of pontic contact in static and dynamic excursions, and the effect of habits were assessed. Life table, Kaplan-Meier and Cox regression analysis were carried out for the 73 RBBs with complete records. A separate analysis of the RBBs provided for patients who attended for the invited review did not show a higher failure rate than those patients who did not attend. Therefore both sets of data were combined.

RESULTS

Of the 73 RBBs provided, 30 had debonded on at least one occasion (41.1%), six of these debonds were due to trauma (20%). The mean survival time of all the restorations was 59.3 months, with a median survival time of 59 months. Senior members of staff (Consultant, Senior Lecturer or Specialist Trainee) provided most restorations (n = 39) and achieved the highest mean survival of 72.6 months and median survival time of 100+ months. RBBs provided by junior staff and students had significantly lower survival times (p <0.05) compared with senior staff. Risk of failure was 3.9 times greater with junior staff and 2.5 times greater with students (p = 0.01 and p = 0.02, respectively). Analysis of all the other factors investigated showed no statistical difference in survival times or in hazard ratios. Analysis of fixed/fixed versus cantilevered bridges was limited by the number of fixed/fixed bridges (n = 11), and only two cantilevered bridges with multiple abutments were provided; both failed within one month.

CONCLUSION

RBBs provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors can for many patients be an acceptable and definitive restoration. Experienced staff achieved the best results, but why this should be was not explained by the individual factors analysed in this study.

A retrospective clinical evaluation of two-unit cantilevered resin-bonded fixed partial dentures

BACKGROUND

The authors conducted a study to examine the clinical performance of two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) that were inserted at The Prince Philip Dental Hospital, University of Hong Kong.

METHODS

The authors recalled patients who had received two-unit cantilevered RBFPDs at least 24 months before the recall examination. The authors recorded the following data: patient's sex and age, operator's experience, prosthesis cementation date, endodontic treatment if performed, bone support, tooth mobility, the presence of shim-stock contacts on the abutment or pontic in intercuspal position, and the presence of aproximal axial contacts adjacent to the prosthesis. They also recorded the date of any debonding with subsequent treatment. They asked the patients qualitative questions about their prostheses.

RESULTS

A total of 269 prostheses were placed in 214 patients and had a mean service life of 51.7 months +/- 19.5 months standard deviation, with a range of 13.2 to 141.6 months. Of 14 failed prostheses, 12 debonded, resulting in a success rate of 94.8 percent and clinical retention rate of 95.5 percent. No discernable rotation or drifting of the abutments was apparent in any of the prostheses. Overall patient satisfaction with RBFPDs was good, with an average assessment score of 8.5.

CONCLUSIONS

The authors observed a 95.5 percent clinical retention rate of 269 two-unit RBFPDs, with no apparent drifting of the abutments. Longer-term follow-up studies are required.

CLINICAL IMPLICATIONS

Two-unit RBFPDs are conservative and clinically retentive prostheses in the short to medium term.

Improved retention of anterior cantilever resin-bonded prostheses by design alteration: an experimental and finite element study

STATEMENT OF PROBLEM

Anterior cantilever resin-bonded prostheses fail as a result of a labio-lingual peeling action, which creates a stress concentration within the adhesive layer.

PURPOSE

The purpose of this study was to identify the factors that determine the retention of an anterior resin-bonded prosthesis and to seek to eliminate the stress concentration within the adhesive layer by fundamentally altering the prosthesis design.

MATERIAL AND METHODS

The first experiment involved 40 Ni/Cr (Wiron 99) beams with a width of 5 mm, thickness of 0.5 mm, and lengths ranging from to 13 to 22 mm. The beams were cemented onto a block of the same material using an adhesive resin luting agent (Panavia 21). The length of the beam that was bonded ranged from 1 to 10 mm, resulting in a bonded area ranging from 5 to 50 mm(2). A load was applied onto the cantilevered portion of the beam 2 mm from the end, causing a peeling action. The force (N) required to debond these beams was measured using a pull-to-fracture test. Subsequently, a second experiment was undertaken, and 7 beams with an altered point of attachment (new design) were tested. The new design had the point of attachment of the cantilevered portion located centrally on the bonded area of the beam. Implementing this new design clinically would result in a cantilevered resin-bonded fixed partial denture that would have the connector arm attached more centrally on the retainer wing. The data were analyzed using a 1-way analysis of variance (alpha = .05), and a Tukey pairwise comparison test was used when the results was statistically significant. Two finite element analysis (FEA) models, one simulating the first experimental design and the other simulating the new design, were created. A load was then applied on the cantilevered portion of the beams similar to the experimental models, and the stress patterns were examined. The numerical values of these resultant stresses were plotted graphically.

RESULTS

The direction of load application, which may be transferred to a clinical setting as labio-lingual forces, was identified as the dominant force responsible for debonding. The new design, which addressed this problem, showed a significant increase (P < .001) in retention. The FEA models identified the stress concentrations within the adhesive layer of the traditional design, which were eliminated when the new design was tested.

CONCLUSIONS

For the in vitro model, loads that may be interpreted clinically as labio-lingual forces resulted in the lowest forces required to cause debonding, and these forces were independent of the surface area of bonding. Altering the point of attachment of the cantilevered portion onto the retainer caused a significant increase in the forces needed to cause debonding.

Clinical performance of Rochette bridges used as immediate provisional restorations for single unit implants in general practice

A retrospective clinical audit of the role and survival of 69 Rochette bridges used as immediate provisional restorations for single tooth, implant-retained crowns was carried out over the period between February 1991 and May 2001. In each case the extracted tooth was immediately temporised using a Rochette bridge with a single wing and pontic and cemented to the abutment tooth without any tooth preparation (Phase I). This bridge was removed at the time of implant placement and recemented (Phase II). At the implant exposure stage the bridge was removed and discarded. In Phase I, 15.9% of the bridges required recementation and 27.5% of the bridges required recementations in phase 2; 7.2% of the bridges required recementations in both phases. An 80% probability of survival was noted after an interval of 200 days for phase I and a 78% probability of survival over the same time interval was observed for Phase II. A significant debond rate was observed when the retainer was a canine in comparison to the other bridges in Phase I. In Phase I the spring cantilever debond rate was significantly higher than that observed on the other bridges. More debondings were observed in males (25.8%) compared with females (7.9%) in Phase I. More debondings were noted in the maxilla than in the mandible in Phase II. The performance characteristics of the metal acrylic Rochette bridge observed in this report supports the conclusion that this type of restoration is an effective means of immediate temporisation for patients undergoing single tooth implant retained restorations.

Retrospective survival analysis of 3-unit fixed-fixed and 2-unit cantilevered fixed partial dentures

To evaluate the cumulative survival (CS) rates of fixed partial dentures (FPDs) retained by full-veneer retainers, and those of resin-bonded FPDs provided by graduating dental students for the replacement of a single missing tooth. In 168 patients, 61 3-unit fixed-fixed FPDs and 25 2-unit cantilevered FPDs retained by full-veneer retainers, and 77 3-unit fixed-fixed resin-bonded FPDs and 47 2-unit cantilevered resin-bonded FPDs, were examined for their retention and integrity. The periodontal health, endodontic status and coronal tissues of all abutment teeth were also evaluated. The survival rates of these various designs were analysed with the Kaplan-Meier method. The mean age of all FPDs was 31 months. At 48 months after their insertion, 3-unit FPDs retained by full-veneer retainers had a CS rate of 82%, followed by 2-unit resin-bonded FPDs at 81%, 2-unit FPDs retained by full-veneer retainers at 77%, and 3-unit resin-bonded FPDs at 63%. No significant difference was found between the four designs (P>0.05). Up to both 48 and 60 months, the most common causes of failure were endodontic for FPDs retained by full-veneer retainers, and dislodgement for resin-bonded FPDs. The 3-unit fixed-fixed FPDs retained by full-veneer retainers had the most favourable prognosis after 48 months for replacing a single missing tooth, but the difference between designs was not statistically significant.

A single-retainer zirconium dioxide ceramic resin-bonded fixed partial denture for single tooth replacement: a clinical report

This clinical report describes a treatment for the replacement of a missing mandibular anterior tooth using a cantilever single-retainer resin-bonded fixed partial denture (RBFPD), fabricated from zirconium dioxide (ZrO2) ceramic. No clinical complications were observed at the 2-year 6-month follow-up examination after placement of the ZrO2 ceramic RBFPD, and satisfactory functional and esthetic results were achieved. A treatment modality using a cantilever ZrO2 ceramic RBFPD is an alternative for single anterior tooth replacement. Further clinical studies are required to evaluate the long-term potential of cantilever single-retainer ZrO2 ceramic RBFPDs.

An investigation of aspects of design of resin-bonded bridges in general dental practice and hospital services

PURPOSE OF STUDY

To assess the design of resin-bonded bridges (RBBs) by dentists, the quality of information provided to a dental laboratory, and aid identification of best practice.

DESIGN

A retrospective case series study of slips for RBB construction, sent by hospital and general dental practitioners to a dental laboratory based in a postgraduate dental institute in Scotland, UK.

MAIN FINDINGS

384 forms were reviewed. For single-tooth replacements, 40% of designs for upper anterior bridges and 46% for lower posterior bridges were fixed-fixed (F-F) when a cantilever design was a better option. Thirty-six (9.3%) of RBB designs involved double abutting. On the laboratory forms, fewer than five (1%) cases included instructions about the thickness of the metal framework and in 48% there was no reference to the extension of the metal framework.

PRINCIPAL CONCLUSIONS

For single-tooth replacements, a relatively high percentage of dentists prescribed a fixed-fixed design for RBBs, despite the evidence advocating the use of a cantilever design. A significant number of dentists used double abutments. The information provided to the laboratory for the construction of resin-bonded bridges was often insufficient.

Survival rates of resin-bonded, glass fiber–reinforced composite fixed partial dentures with a mean follow-up of 42 months: A pilot study

STATEMENT OF PROBLEM

Although short-term clinical data exist for resin-bonded, glass fiber-reinforced composite fixed partial dentures (FPDs), long-term data are needed.

PURPOSE

The survival rates of 29 resin-bonded, glass fiber-reinforced composite fixed partial dentures were evaluated in this clinical study for periods of up to 42 months.

MATERIAL AND METHODS

FPDs were fabricated to replace 1 to 3 missing maxillary or mandibular teeth of 29 patients not able to be treated with conventional FPDs. Originally, there were 37 patients (the drop-out rate was 22%). The FPDs were retained with wings, inlays, complete coverage crowns, or combinations of these that were bonded to tooth structure. The FPD frameworks were made of continuous unidirectional E-glass fibers with a multiphase polymer matrix and light-polymerized particulate composite veneer. The patients were recalled for examinations, where a general dental examination was performed, 1 to 3 times per year for up to 63 months (minimum 24 months, mean 42 months). Partial or complete total debonding of the FPD or the framework fracture was considered a treatment failure. The data were analyzed with the Kaplan-Meier survival test (alpha=.05).

RESULTS

Two resin frameworks fractured, and 3 frameworks were debonded. Kaplan-Meier survival probability at 63 months was 75%. Three of the failed FPDs were rebonded or repaired in situ, producing a functional survival rate of 93% after rebonding or repairing (mean survival time was 55 months).

CONCLUSION

The results of this clinical study of 29 prostheses suggest that glass fiber-reinforced FPDs may be a possible alternative to cast metal resin-bonded FPDs. These restorations were successfully used as multiple-unit prostheses that employed a variety of abutment tooth preparation designs.

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%).

A comparison of 3 alloy surface treatments for resin-bonded prostheses

PURPOSE

The most frequent cause of clinical failure of resin-bonded fixed partial dentures is a debonding at the metal-cement interface. The purpose of this in vitro study was to compare the tensile bond strengths of 3 different alloy-surface treatments when cemented to human enamel with a resin cement.

MATERIALS AND METHODS

Cylinders of a nickel-chromium-beryllium (Ni-Cr-Be) and a gold-palladium (Au-Pd) alloy were fabricated and assigned to different surface treatment groups as follows: Group 1: Ni-Cr-Be, chemically etched; Group 2: Au-Pd, airborne particle-abraded and tin-plated; and Group 3: Au-Pd, airborne particle-abraded and treated with the Alloy Primer (Kuraray Co, LTD, Osaka, Japan). The cylinders were bonded to the enamel surfaces of extracted, human third molars and stored in normal saline at 37 degrees C for 48 hours. The tensile bond strength of 21 specimens from each group was measured on a Universal Testing Machine (Instron, Canton, MA). Three failed specimens of each group were evaluated using scanning electron microscopy and energy dispersive spectroscopy.

RESULTS

Statistically significant differences (p <.05) were found between all 3 treatment groups. The mean tensile bond strengths (+/- the standard error of mean) recorded as follows: Group 1: 10.6 MPa (+/-1.3), Group 2: 0.9 MPa (+/-0.2), and Group 3: 13.4 MPa (+/-1.0). Specimens from groups 1 and 3 revealed a trend towards mixture of cohesive, within the resin cement, and adhesive failures at the metal-cement interface. Group 2 specimens exhibited primarily adhesive failures at the metal-cement interface.

CONCLUSIONS

The tensile bond strength of Au-Pd alloy specimens was significantly increased with the Alloy Primer.

Resin-bonded, glass fiber-reinforced composite fixed partial dentures: a clinical study

STATEMENT OF PROBLEM

Resin-bonded, glass fiber-reinforced composite fixed partial dentures (FPDs) have been under development for some time. There is a lack of data regarding the clinical usefulness of such prostheses.

PURPOSE

The clinical performance of 31 resin-bonded, glass fiber-reinforced composite fixed partial dentures was evaluated in a preliminary study.

MATERIAL AND METHODS

The prostheses were made to replace 1 to 3 missing maxillary or mandibular teeth in each of 31 patients. The prostheses had a framework made of continuous unidirectional E-glass fibers with multiphase polymer matrix and light-polymerized particulate composite resin veneering. The prostheses were examined after 6-month periods for up to 24 months (mean follow-up time was 14 months). Partial or total debonding of the prostheses or the framework fracture was considered a treatment failure.

RESULTS

Two prostheses debonded during the follow-up period; 1 debonding was related to improper occlusal adjustment and the other to unknown reasons. Kaplan-Meier survival probability at 24 months was 93%. No framework fractures were observed.

CONCLUSION

The results of this preliminary study suggest that the resin-bonded, glass fiber-reinforced FPDs may be an alternative for resin-bonded FPDs with a cast metal framework.

Influence of design and mode of loading on the fracture strength of all-ceramic resin-bonded fixed partial dentures: an in vitro study in a dual-axis chewing simulator

STATEMENT OF PROBLEM

In a clinical study, all-ceramic resin-bonded fixed partial dentures showed a high rate of fractures within the first years of service but remained in function as cantilevered restorations. No data are available on the fracture strength of such cantilevered restorations.

PURPOSE

This in vitro study evaluated the influence of design and mode of loading on the fracture strength of all-ceramic resin-bonded fixed partial dentures.

MATERIAL AND METHODS

Forty-eight frameworks were copy milled using the aluminum-oxide ceramic In-Ceram, glass-infiltrated, and circularly veneered with feldspathic porcelain to replace a maxillary incisor on a test cast. The airborne particle-abraded restorations were bonded to acid-etched human abutments using composite. Twenty-four restorations used a conventional 2-retainer design and another 24 restorations used a cantilevered single-retainer design. Subgroups of 8 specimens were subjected to a quasi-static load in the direction of the long axis of the abutments (0 degrees) or in an angle of 45 degrees. Additional subgroups were subjected to dynamic loading under 45 degrees with either 50 or 25 N in a dual-axis chewing simulator until fracture.

RESULTS

Mean fracture strengths, under 45-degree quasi-static loading, were between 134 and 174 N and under 0-degree loading about 233 N. Samples subjected to dynamic loading fractured after 25 to over 200,000 loading cycles.

CONCLUSION

Direction of loading exhibited a significant influence on the fracture strength, regardless of the retainer design. The applied dynamic loading force, regardless of the retainer design, had a significant influence on the loading cycles until fracture.

Short and sticky options in the treatment of the partially dentate patient

As we move into the twenty-first century, patterns of dental disease in adults are changing. Surveys of adult dental health indicate that more people are keeping their teeth for longer in life. In many cases, the ravages of dental disease and the cumulative effect of a lifetime of restorative dentistry lead to gradual tooth loss. For many of these patients, restoration of a complete dentition may not be feasible nor desirable. In recent years, functionally oriented treatment planning has become acceptable in light of recent research findings. Using this approach, treatment efforts and resources are directed principally at retaining the 'strategic' part of the dentition in the long term, ie, the anterior and premolar teeth. This paper describes, with the aid of treated cases, a means of combining a shortened dental arch strategy with resin bonded bridgework. With the aid of recent research in this area of clinical practice, some suggestions as to the use of the technique are also described.

In-vitro study of fracture strength and marginal adaptation of fibre-reinforced adhesive fixed partial inlay dentures

The aim of this study was to examine in-vitro whether adhesive fixed posterior inlay dentures (AFPID) made with the fibreglass-reinforced Vectris/Targis system (Ivoclar, Schaan, FL) have a fracture strength and a satisfactory marginal adaptation which can occur under clinical conditions. Extracted human third molars were embedded in a PMMA resin 10 mm apart to represent a molar gap. Two preparation methods were used: a box-shaped preparation technique (n = 8) and a tub-shaped preparation technique (n = 8). All AFPIDs were adhesively inserted using the dual curing composite cement, Variolink-high-viscosity (Vivadent, Schaan, FL). After thermocycling and mechanical loading (TCML: 6000 x 5 degrees C/55 degrees C, 1.2 Mio x 50 N, 1.66 Hz) in an artificial environment, the bridges were loaded to failure. Marginal adaption was investigated before and after TCML with the replica technique. After TCML, no significant difference was found in fracture strength between tub-shaped-preparation (median = 722 N, bending median = 0.9 mm) and box-shaped preparation (median = 696 N, bending median = 1.2 mm). A 'perfect margin' was observed in more than 60% of the investigated areas in both preparation techniques. With these values, the bridges can occur under clinical conditions and thus a clinical employment should be considered.

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.

Risk factors and multiple failures in posterior resin-bonded bridges in a 5-year multi-practice clinical trial

OBJECTIVES

A randomized controlled clinical trial was undertaken, to study the influence of some patient- and operator-dependent variables on the survival of posterior resin-bonded bridges (PRBBs) and to assess the survival of replacement' PRBBs. This report contains some of the results of the 5-year analysis.

METHODS

Survival was defined at three levels: (1) complete survival (without any debonding), (2) functional survival (i.e. survival after one loss of retention) and (3) replacement survival (survival of 'replacement' PRBBs, inserted after rebonded bridges suffered a second dislodgement). Potential risk factors were analysed with Cox's proportional hazards model and differences were tested for significance with the Breslow test. Observed effects are expressed as conditional-relative-risk (CRR). Survival of 'replacement' PRBBs was assessed with the Kaplan-Meier method.

RESULTS

Factors showing significant influences on complete survival were: 'location' (highest risk for mandibular PRBBs: CRR = 2.2), 'aetiology' (higher risk in treatment of aplasia: CRR = 2.9), and 'time of existence' (open spaces existing less than 2 years before insertion of PRBB: CRR: 2.0). The factor 'large open spaces in the mandible' was a risk for both complete and functional survival (CCR values 3.1 and 3.5, respectively). The survival of mandibular and maxillary 'replacement' PRBBs after 5 years was 19 +/- 7% and 31 +/- 18%, respectively.

CONCLUSIONS

Risk factors for PRBBs were: 'location', 'aetiology', 'time of existence', 'isolation method' and 'large open spaces in the mandible'. Mandibular 'replacement' PRBBs showed such an unacceptably low survival rate that fabrication is not recommended.

A five-year multi-practice clinical study on posterior resin-bonded bridges

Previous clinical observations have revealed that resin-bonded bridges for posterior tooth replacements are less retentive than anterior resin-bonded bridges. Improved bonding procedures and preparation designs, however, may have a positive effect on the functional durability of these restorations. The present study reports the final analysis of a randomized controlled clinical trial in which different designs of posterior resin-bonded bridges were evaluated for a period of at least 5 years. The operational hypothesis was that the bonding system and the preparation design used in posterior resin-bonded bridges have an influence on the survival and clinical functioning of these restorations. Survival in this study was defined at two levels: (1) 'complete' survival (survival without any debonding), and (2) 'functional' survival (survival including loss of retention on one occasion and successful rebonding of the original RBB without further debonding). With regard to 'complete' survival, no significant differences were found between the bonding systems used for adherence of the restorations to abutment teeth (etching/Clearfil F2, sandblasting/Panavia EX, and silica-coating/Microfill Pontic C). The variable 'preparation form' (conventional preparation form vs. modified preparation form) for complete survival was statistically in favor of the modified preparation form (62% vs. 46%), but did not influence the functional survival. With regard to 'functional' survival, the combination of silica coating and Microfill Pontic C was more retentive than the other bonding systems (90% survival vs. 72% and 75%, p < 0.01). Factor location was found to be highly significant for both survival levels [Cox's PH model, p = 0.0002 (Cox, 1972)]: The five-year 'complete' survival rates were 65% for maxillary restorations and 40% for mandibular restorations, while the five-year 'functional' survival rates were 89% and 68%, respectively. It is concluded that preparation of grooves in abutment teeth for posterior resin-bonded bridges is beneficial to their chance of survival. Resin-bonded bridges placed in the maxilla have a better prognosis than those made in the mandible. The bonding systems used in this study appear to have no influence on the chance of failure. In rebonded posterior resin-bonded bridges, the bonding system silica-coating/Microfill Pontic C was more retentive than the other systems tested.

Bonding to alumina ceramic in restorative dentistry: clinical results over up to 5 years

OBJECTIVES

The purpose of this clinical pilot study was to evaluate the resin bond to alumina ceramic in vivo when using a bonding method which had been shown to be successful in laboratory testing.

METHODS

Seventeen resin-bonded all-ceramic bridges and splints fabricated from a glass-infiltrated alumina ceramic were tribochemically silica coated and resin bonded to their abutment teeth. The patients were recalled every 6 months to evaluate the restorations with regard to function and possible failures.

RESULTS

Over a mean observation time of 3.8 +/- 1.6 years some ceramic fractures occurred. However, the resin bond between the teeth and the alumina ceramic always remained stable.

CONCLUSIONS

Silica coating of alumina ceramic resulted in a durable resin bond over up to 5 years.

Clinical performance of resin-bonded fixed partial dentures and extracoronal attachments for removable prostheses

STATEMENT OF PROBLEM

It is important to evaluate the long-term clinical performance of resin-bonded fixed partial dentures and extracoronal attachments for removable prostheses.

PURPOSE

A prospective, long-term clinical study was conducted to evaluate the success of resin-bonded fixed partial dentures since 1985 and of resin-bonded extracoronal attachments from 1987.

METHODS

Until 1993, a total of 130 resin-bonded fixed partial dentures had been seated in 101 patients, as well as 12 removable partial dentures (RPDs) with 24 extracoronal retainers in 10 patients. The clinical treatment protocol and the laboratory procedures were standardized. By the end of 1993, it was possible to reexamine 98 patients with a total of 127 resin-bonded fixed partial dentures and all 10 patients with removable partial dentures. The average time in function for the resin-bonded fixed partial dentures at the time of examination was 3.4 years and 2.3 years for the removable restorations.

RESULTS

During the period of observation, one retainer failed on six of the resin-bonded fixed partial dentures, which represents a failure rate of 4.7%. Debonding of extracoronal attachments was recorded for 8.3% of the total number of retainers.

CONCLUSION

The resin-bonded fixed partial denture technique can be considered to be a clinically reliable method of treatment, and permits the expansion of indications beyond a classical three-unit resin-bonded fixed partial denture. Long-term clinical success of removable partial dentures with resin-bonded extracoronal retainers warrants additional clinical studies.

Long-term survival data from a clinical trial on resin-bonded bridges

OBJECTIVES

A clinical trial, involving 203 resin-bonded bridges (RBBs) was undertaken to investigate the influence of retainer-type and luting material on the survival of these restorations.

METHODS

For this evaluation, 157 patients were available (14% of the original sample was lost to follow-up or excluded from the study following the stopping criteria). Fifty per cent of the patients were questioned concerning the fate of the RBBs and 59% of questioned patients were examined clinically. The patients that were seen for examination were representatives of the experimental groups. The findings from the clinical examination were compared with the data obtained from the questionnaire. Missing data were censored at the date of the last available information. Kaplan-Meier estimates were calculated to assess the survivals at the endpoints and compared using Cox's proportional hazards procedure.

RESULTS

A significant difference was found between perforated (P-type) and etched (E-type) RBBs (P = 0.05) for original bonded restorations but not when rebonded RBBs were taken into account. The results of the survival analysis were: anterior P-type, 49 +/- 7% after 10.5 years: anterior E-type, 57 +/- 7% after 10.5 years; posterior P-type, 18 +/- 11% after 6.8 years; posterior E-type, 37 +/- 13% after 10.2 years. Survivals of RBBs that were rebonded once during the evaluation period were 62 +/- 9% (11.0 years) for anterior RBBs and 51 +/- 11% (10.2 years) for posterior RBBs.

CONCLUSIONS

The factor location (anterior versus posterior) was as in previous analyses, highly significant. Differences in survival between cementation materials were not significant.

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.

The clinical performance of cantilevered resin-bonded bridgework

OBJECTIVES

The technique of resin-bonded bridgework is a well-accepted clinical technique to replace missing teeth. This study assesses the clinical performance of cantilevered resin-bonded bridgework provided in a university teaching hospital environment.

METHODS

One-hundred and twelve patients who had a total of 142 cantilevered bridges were either examined or completed a questionnaire regarding their bridgework. The following data were recorded for each resin-bonded bridge: gender of patient, age at bridge cementation, date of initial cementation, tooth replaced, abutment(s) involved, and grade of clinician responsible for the provision of the bridge. Details of the incidence of debonding with date(s) and the subsequent treatment in relation to the debonded resin-bonded bridge were recorded. The subjects examined indicated their degree of satisfaction with their bridgework on a visual analogue scale.

RESULTS

There were 112 patients with a total of 142 bridges, 116 (82%) maxillary and 26 (18%) mandibular. The mean length of clinical service was 36.2 months (s.d. 17.2 months). Only single pontics were included in the bridges, with almost half (49%) replacing a lateral incisor. Of the cantilever resin-bonded bridges studied, 88% remained bonded over the period of the study. A success rate of 94% is reported.

CONCLUSION

This study confirms the clinical success of cantilever resin-bonded bridges particularly in the replacement of maxillary lateral incisors, maxillary premolar and permanent mandibular teeth.

Long-term clinical performance of resin-bonded fixed partial dentures placed in a developing country

PURPOSE

This study assesses the clinical performance of 92 resin-bonded fixed partial dentures (FPDs) placed at four private practices in Karachi, Pakistan, between 1982 and 1991.

MATERIALS AND METHODS

The distribution of the FPDs was 9 perforated, 45 electrolytically etched, and 38 silicoated. Twenty-five FPDs replaced anterior teeth and 67 replaced posterior teeth. There were 66 FPDs with single pontics and 26 with multiple pontics. The perforated designs used a restorative composite for cementation, whereas the electrolytically etched and silicoated designs used a composite luting cement. The observation periods for the perforated, electrolytically etched and silicoated FPDs were 114, 99, and 30 months respectively.

RESULTS

During the evaluation period, 27 FPDs (29%) failed; of these, 4 were perforated, 18 were electrolytically etched, and 5 were silicoated. The mean (+/-SD) duration of the successful clinical service for all FPDs was 41 +/- 26 months. The mean time to failure for the FPDs that did not survive was 35 +/- 23 months. The silicoated FPDs tended to have early failure, as did the FPDs with multiple pontics and those in the mandibular arch. Anterior and posterior FPDs performed equally well.

CONCLUSIONS

These findings, in conjunction with those from Europe and North America, show that resin-bonded FPD technology is as successful in a developing country as in industrialized areas of the world.

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 peel failure of resin-bonded Ni/Cr beams: an experimental and finite element study

Tensile bond strength data for resin-bonded bridge cements would predict failure loads in excess of 1000 N when based on available bonded surface area. Such loads are unlikely to be encountered clinically, yet these bridges frequently fail. Loading conditions resulting in a peeling action at the adhesive interface may provide a more probable explanation for failure rather than being attributable to poor clinical or laboratory technique. This hypothesis was investigated by bonding grit-blasted Ni/Cr alloy beams of different thicknesses to a block of the same alloy using a resin-bonded bridge cement, leaving half the length of the beam free. Beams were pulled off the block with a peeling action by applying a tensile load to the free end of the beam and load at failure recorded. Fractured surfaces were examined under SEM. A two-dimensional finite element model of a section through the peel test arrangement was used to produce data of the stress distribution in the adhesive layer. Load at failure was closely correlated to beam thickness. Using this data and known tensile bond strength values it was possible to predict the loads necessary to cause adhesive failure of the beam, which were found to correlate closely with the experimental measurements. It was concluded that design and the stiffness of the retainers can have a potentially profound effect on the adhesive quality of resin-bonded bridges.