Comparison of 2 bonding systems and survival of fiber-reinforced composite inlay fixed partial dentures

PURPOSE: This pilot clinical trial evaluated the clinical behavior of 3-unit inlay fixed partial dentures (IFPDs) made of the glass-fiber composite system SR Adoro/Vectris and luted with 2 different bonding systems over an observation period of 2 years. MATERIALS AND METHODS: Thirty-nine glass-fiber-reinforced composite IFPDs were made to replace 1 missing maxillary or mandibular tooth. Nineteen IFPDs were randomly assigned to group A and luted with a 2-step bonding system (Excite DSC), while the other 20 IFPDs of group B were cemented with a 3-step adhesive (Syntac). Events such as partial or total debonding of the IFPDs, fracture of the framework, or veneer and fiber exposures were considered failures. Color match, marginal discoloration, secondary caries, marginal adaptation, postoperative sensitivity, and surface texture were evaluated according to the United States Public Health Service modified criteria. RESULTS: Two debondings and 2 fiber exposures occurred during the observation period. All failures occurred in group A. Some fatigue microcracks in the pontic area of the 2 detached IFPDs were observed under scanning electron microscopy. The postoperative sensitivity of group A was much higher than that of group B, and the abutments luted with Excite DCS showed postoperative sensitivity during the first month in 42.2% of cases. The sensitivity disappeared completely after 6 months. Statistical analysis indicated significant differences in postoperative sensitivity (P < .05) between the 2 groups. CONCLUSION: The IFPDs bonded with a 3-step adhesive demonstrated good clinical service in the short observation period. The microfractures of the layering material observed on the debonded IFPDs may suggest excessive flexibility of the fiber structures, which occurs if the framework is fabricated without observing the recommended dimensions.     

Chairside prefabricated fiber-reinforced resin composite fixed partial dentures.

The introduction of pre-impregnated fiber-reinforced resin composites has provided the dental profession with the opportunity to fabricate and deliver adhesive, esthetic, and metal-free tooth replacements. Utilizing this technology, a prefabricated fiber-reinforced resin composite fixed partial denture prototype that allows rapid, cost-effective, and noninvasive fixed tooth replacement for single anterior teeth has been developed. Ideal situations for this type of service include: a fixed replacement following tooth loss from trauma; a fixed tooth replacement in medically compromised patients who cannot sit for extended periods of time or have local anesthesia; periodontally compromised abutments; a fixed space maintainer following orthodontic movement; and a fixed provisional during the post implant healing phase prior to loading. This article describes the framework construction and placement protocol for the prefabricated fiber-reinforced resin composite fixed partial denture.     

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.     

Damage mechanics and load failure of fiber-reinforced composite fixed partial dentures

OBJECTIVES: Damage mechanics has been defined as the study of the initiation (initial failure) and accumulation of damage to and including rupture (final failure). This study was designed to evaluate the effect of increasing fiber-reinforced composite (FRC) substructure within a standardized fixed partial denture (FPD) model on the failure performance, in terms of damage mechanics. METHODS: The two FRC restorative systems, Targis/Vectris (TV) (Ivoclar Vivadent) and EverStick (ES) (Stick Tech with Gradia, GC Corp.), were used to restore the molar FPD model (1.5 mm axial and 2.0 mm occlusal reduction). Templates were used to standardize substructure designs with 0, 18, 43, and 66% cross-sectional FRC volume fraction (V(FRC)) of fiber substructure. Specimens (n = 5) were homogenized at 29 points and stored for 1 week at 37 degrees C in distilled water. Specimens were luted with calcium hydroxide, then statically loaded until failure. Initial failure (IF), final failure (FF) and the mode of failure were recorded. RESULTS: The lowest mean load to initial failure was 530 N (TV 18%) and the highest was 1208 N (ES 66%). Linear regression analysis calculated the Pearson's correlation coefficient (r) for the interactions between V(FRC) and IF (ES: r = 0.7879, TV: r = 0.6184), V(FRC) and FF (ES: r = 0.912, TV: r = 0.8152), and between IF and FF (ES: r = 0.892, TV: r = 0.7237). Unreinforced specimens universally fractured instantaneously. SIGNIFICANCE: The highest loads to initial and final failure were yielded by specimens with the highest cross-sectional V(FRC).     

Fracture resistance of inlay-retained fixed partial dentures reinforced with fiber-reinforced composite

In this study, the effect on the fracture load of inlay-retained composite fixed partial dentures (FPDs) caused by reinforcing them with fiber-reinforced composite (FRC) in different positions was examined. Experimental FPDs were fabricated using Estenia/EG Fiber (Kuraray Medical). Pontic reinforcement was then performed in one of the following three ways: reinforced the central area in a single line or in double straight lines, or reinforced the bottom in a curved line. The finding was that, when the area ranging from the connector to the bottom of the pontic was reinforced with FRC in a curved line, the fracture load of the FPDs tended to become higher. In addition, the FPDs fractured mainly at the veneering composite of the connector area. Based on the results of this study, it was concluded that reinforcement using FRC is effective, and that the veneering composite in the connector area needs to have sufficient strength to prevent the fractures.     

Effects of two preparation designs and pontic distance on bending and fracture strength of fiber-reinforced composite inlay fixed partial dentures

STATEMENT OF PROBLEM: Joint fractures observed in Targis/Vectris inlay adhesive fixed restorations may be related to the preparation design. PURPOSE: This in vitro study investigated the effects of the proximal tooth preparation design and the pontic distance on the fracture strength and the amount of bending of fiber-reinforced inlay adhesive fixed partial dentures. MATERIALS AND METHODS: Forty extracted premolars and 40 molars were embedded in a PMMA resin to represent a premolar and molar mesiodistal separation distance of 7 mm and 11 mm, respectively. Two preparation designs were used (proximal box and tub-shaped). The sample size was 10 for each group. Fiber-reinforced inlay adhesive fixed partial dentures were fabricated by use of the Targis/Vectris system and luted adhesively to the teeth with Variolink luting agent. A vertical force was loaded to the center of the fixed partial dentures at a crosshead speed of 1 mm/min. The initial bending (mm) prior to fracture was evaluated by measuring the distance the test rod moved from a 10 N preload to fracture. The differences in the mean fracture strength and the average amount of bending as a function of the preparation designs and pontic distances were compared by use of a 2-way analysis of variance (alpha=.05). The specimens were examined optically for the type of failure with a stereomicroscope. The fracture surface of the specimens was examined by scanning electron microscopy, and radiography was used to investigate the surface morphological features at the failure sites and to determine the fracture mode. A chi-square test was used to identify the differences in the debonding rates between the types of preparation designs and the pontic distance (alpha=.05). RESULTS: The mean fracture strength and the standard deviation of the fiber-reinforced inlay retained adhesive fixed partial denture group was 1368+/-212 N for the 7-mm tub group, 885+/-109 N for the 11-mm tub group, 1779+/-317 N for the 7-mm box group, and 1336+/-281 N for the 11-mm box group. The fracture strength was significantly higher in the 7-mm pontic distance (P<.001) and for the box-shaped tooth preparation (P<.001). The amount of bending was significantly greater in the 7-mm pontic distance (P=.025) and the box-shaped tooth preparation (P=.002). Debonding was observed only in premolar teeth and tub-shaped design groups. CONCLUSION: The box-shaped tooth preparation may be considered for restoration of a missing single posterior tooth with fiber-reinforced inlay adhesive fixed partial dentures.     

In vitro fracture resistance of four-unit fiber-reinforced composite fixed partial dentures.

OBJECTIVES: The aim of this in vitro study was to investigate the influence of glass fiber-reinforcement on the fracture resistance of four-unit composite fixed partial dentures (FPDs) in the posterior region. METHODS: A total of 70 FPDs were fabricated of the composites Sinfony, Vita Zeta and Targis. With each material, 10 FPDs were made without glass fiber-reinforcement and 10 were reinforced with the new glass fiber system EverStick. In addition, 10 FPDs were fabricated of the material combination Targis/Vectris. After thermocycling, all FPDs were loaded until failure in a universal testing machine. The FPDs were then cut and cross-sectional areas were examined by scanning electron microscopy (SEM). RESULTS: The load to fracture of the fiber-reinforced FPDs lay between 615 and 1191 N, which was significantly greater than the values found with unreinforced FPDs (between 178 and 307 N). The highest values were found with the combinations Targis/Vectris (1191 N) and Sinfony/EverStick (1137 N). SEM showed that the FPDs with EverStick reinforcement not only exhibited fracture lines in the fiber-composite interface, but also more often in the area of the fiber-reinforcement than was the case with the FPDs with Vectris reinforcement. The load to fracture was not significantly dependent on fiber quantity or course of fracture. SIGNIFICANCE: It may be concluded that the fracture resistance of four-unit composite FPDs can be significantly raised by glass fiber frameworks (p<0.05). The reinforcement effect of EverStick depended significantly on the composite used (p<0.05).     

Three-year clinical evaluation of fiber-reinforced composite fixed partial dentures using prefabricated pontics

PURPOSE: The purpose of this study was to evaluate the clinical performance of surface-retained adhesive composite fixed partial dentures reinforced by an ultra-high molecular weight polyethylene (UHMWP) fiber (Ribbond THM). MATERIALS AND METHODS: Twenty-three surface-retained fiber reinforced composite (FRC) fixed partial dentures (FPD) were placed by two operators in 23 patients, each with a single missing tooth. The restorations included prefabricated composite resin pontics, and no preparations were done on the lingual surfaces of the abutment teeth. The patients were recalled for examinations every year for up to 3 years. Restorations were evaluated directly using the modified Ryge criteria. The minimum observation period was 1 year and the maximum observation period was 3 years. RESULTS: At baseline, 23 restorations were graded as Alpha for all parameters. At one year and two years (n = 21), three Bravos for wear resistance and surface texture/gingival inflammation and two Bravos for color match were observed. Twenty-one of 23 restorations were retained at the end of two years (91.3%) and 78.3% were retained after a maximum of 3 years. CONCLUSION: The results of this clinical study suggestthat UHMWP FRC FPDs are quite acceptable at least forthree years. However, further clinical investigations are still needed for improved long-term clinical performance.     

Alternative fabrication method for chairside fiber-reinforced composite resin provisional fixed partial dentures

A high level of clinical skill is required for fabricating a provisional fixed partial denture with fiber-reinforced composite resin (FRC) using either the direct or chairside technique. The freehand approach to restoring missing teeth represents a challenge to the clinician, particularly when shaping and finishing a hygienic pontic. This technical report describes a simplified method for chairside fabrication of a fixed dental prosthesis with FRC. It is based on using a translucent template to guide the buildup procedure and to ensure optimal anatomy and function.     

Finite element analysis of fiber-reinforced fixed partial dentures

Two-dimensional finite element models were created for a three-unit posterior fixed partial denture. An experimental resin-impregnated glass fiber was used as the fiber-reinforced composite (FRC) for the framework. The FRC was evaluated using varying combinations of position and thickness, alongside with two types of veneering composite. A load of 50 N simulating bite force was applied at the pontic in a vertical direction. Tensile stress was examined using a finite element analysis program. Model without FRC showed tensile stress concentrations within the veneering composite on the cervical side of the pontic--from the connector area to the bottom of the pontic. Model with FRC at the top of the pontic had almost the same stress distribution as the model without FRC. Models with 0.4-0.8 mm thick FRC positioned at the bottom of the pontic showed maximum tensile stresses reduced by 4-19% within the veneering composite.     

Marginal adaptation of 1 fiber-reinforced composite and 2 all-ceramic inlay fixed partial denture systems

PURPOSE: The aim of this in vitro study was to evaluate the marginal adaptation and retention of inlay fixed partial dentures (IFPDs) made with 1 fiber-reinforced composite and 2 different ceramic materials using quantitative scanning electron microscope analysis after thermal cycling and mechanical loading, which simulated approximately 5 years of oral service. MATERIALS AND METHODS: Eighteen IFPDs made with fiber-reinforced composite (SR Adoro/Vectris), zirconium oxide-TZP (Cercon), and magnesia partially stabilized zirconia (DC-Leolux) covered with silica-based ceramics were tested in this study. The specimens were mechanically loaded in the vestibular cusp of the pontic element in a computer-controlled masticator with 1,200,000 half-sinusoid mechanical cycles of maximum 49 N each at a frequency of 1.7 Hz. A total of 3,000 thermocycles at 5 degrees C and 55 degrees C, 2 minutes each, were performed simultaneously. The marginal adaptation was analyzed at the interface of the luting composite and the abutment inlay/onlay (CI) and at the interface of the tooth and the luting composite (TC). RESULTS: The percentages of continuous margin at the CI interface were 94.6 +/- 3.1 and 88 +/- 6.7 for Adoro/Vectris, 92.9 +/- 5 and 85.7 +/- 6.1 for Cercon, and 96.2 +/- 2.1 and 82.2 +/- 9.8 for DC-Leolux, respectively, before and after loading. The percentages of continuous margin at the TC interface were 86.7 +/- 6.7 and 62.5 +/- 16.4 for Adoro/Vectris, 93.3 +/- 3.4 and 83.2 +/- 5.9 for Cercon, and 96.1 +/- 2.4 and 75.3 +/- 7 for DC-Leolux. Statistically significant differences were found after loading between the fiber-reinforced composite and the 2 ceramic systems at the TC interface. CONCLUSION: Within the limitations of this experimental study with regard to the sample size and contacting vectors, the results showed that flexibility of the framework may play an important role in the marginal adaptation of the IFPDs. More rigid materials may transfer less stress to the margins, thus promoting a more stable adhesion to the dental tissues.     

Flexural properties of the bulk fiber-reinforced composite DC-tell used in fixed partial dentures

PURPOSE: The aim of this study was to measure the flexural properties of fiber-reinforced composite (FRC) used in frameworks of fixed partial dentures. In addition, the influence of water storage on the properties was determined. MATERIALS AND METHODS: Rhombic test specimens for four groups were milled from bulk FRC material DC-Tell. The test specimens of the first group were stored and tested dry. In the second group, the test specimens were water stored for 3 months at 37 +/- 1 degrees C and tested in water. The specimens of the third group were also water stored, but they were tested dry at room temperature. Water-stored test specimens of the fourth group were dehydrated and tested dry at room temperature. A three-point bending test was used to measure the flexural properties. The quantity of glass fibers in the test specimens was determined by combustion analysis. Water uptake was calculated after 3 months of water immersion. The direction and length of fibers were examined, and elemental composition was determined. RESULTS: Water storage decreased the flexural strength by 66% and flexural modulus by 60%. After dehydration, the flexural strength did not recover to the same level as the flexural strength of the dry-group specimens. The fiber content was 38% by volume. Water uptake was 3 wt%. The reinforcement of DC-Tell was short fibers in random orientation, and the elemental composition of fibers was similar to that of E-glass. CONCLUSION: Water storage decreases the flexural properties of the bulk fiber-reinforced composite DC-Tell. This may restrict the use of DC-Tell as a framework of crowns and bridges in the oral cavity in the long term.     

All-ceramic inlay-retained fixed partial dentures: preliminary results from a clinical study

OBJECTIVES: The objective of this study was to evaluate the clinical performance of zirconia-based all-ceramic fixed partial dentures anchored by inlays. METHODS: A total of thirty FPDs, manufactured using a zirconia frame and veneered with press ceramic, were anchored by use of inlay retainers. All FPDs were designed to replace one missing molar and were adhesively luted by use of one of two different resin cements. Documentation included failures and other complications, plaque accumulation, and aesthetic and functional performance. Statistical analysis was performed using a cox-regression model. RESULTS: During the 12 months observation period a total of thirteen clinically relevant complications occurred-four delaminations of the veneer and six decementations. Three FPDs had to be replaced because of a fracture of the framework. The cement chosen, the location, and the design of the retainer had no statistically significant effect on the occurrence of complications. During the observation period, accumulation of plaque on the abutment teeth was not significantly greater than on reference teeth. Postoperative sensitivity did not differ significantly between the different luting cement groups. The aesthetic and functional performance of the FPDs was acceptable. CONCLUSIONS: Improved adhesion between resin cement and inlay retainer is desirable before general recommendation of all-ceramic inlay-retained FPDs. Use of different luting cements seems to have no effect on the occurrence of complications.     

Use of short fiber-reinforced composite with semi-interpenetrating polymer network matrix in fixed partial dentures

OBJECTIVES: The aim of this study was to determine the static load-bearing capacity of fixed partial dentures (FPDs) made of experimental composite resin (FC) with short fiber fillers and interpenetrating polymer network (IPN) polymer matrix. MATERIALS AND METHODS: Experimental composite FC resin was prepared by mixing short E-glass fibers (3mm in length) of 22.5wt% and IPN-resin 22.5wt% with silane treated silica fillers 55wt%. Four groups of FPDs (3-unit) were fabricated (n=6); Group A: made from commercial composite resin (Sinfony dentin, 3M-ESPE, control), Group B: Sinfony and fiber-reinforced composite (FRC) substructure, Group C: made from FC, Group D: made from FC with 1mm surface layer of Sinfony. The bridges were polymerized with a hand-light curing unit for 40s then post-cured in vacuum curing device (Visio Beta) for 15min before they were statically loaded with speed of 1mm/min until fracture. Failure modes were visually examined. Data were analyzed using ANOVA (p=0.05). RESULTS: ANOVA revealed that bridges made from experimental fiber composite had statistically significantly higher load-bearing capacity (2171N) (p<0.05) than the control restorations (1482N). SIGNIFICANCE: Restorations made from short glass fiber containing composite resin with IPN-polymer matrix showed better load bearing capacity than in those made with conventional composites resin and similar with those reinforced with FRC-substructure.     

Five-year survival of 3-unit fiber-reinforced composite fixed partial dentures in the anterior area

ObjectivesThe purpose of this clinical study was to evaluate the long-term outcome of 3-unit anterior fixed partial dentures (FPDs) made of fiber-reinforced resin composite (FRC), and to identify design factors influencing the survival rate.Methods52 patients (26 females, 26 males) received 60 indirectly made FRC FPDs, using pre-impregnated unidirectional glass fibers, requiring manual wetting, as framework material. FPDs were surface (n = 48) or hybrid (n = 12) retained and mainly located in the upper jaw. Hybrid FPDs had a combination of retainers; i.e. crown at one and surface retention at the other abutment tooth. Surface FPDs were either purely adhesively retained (n = 29) or with additional mechanical retention (n = 19). Follow-up period was at minimum 5 years, with check-ups every 1–2 years. Six operators were involved, in three centers in the Netherlands, Finland and Sweden. Survival rates, including repairable defects of FPDs, and success rates were determined.ResultsKaplan–Meier survival rate at 5 years was 64% (SE 7%). For the level of success, values were 45% (SE 7%) and the estimated median survival time 58 (SE 10.1) months. For surface FPDs, additional mechanical retention did not improve survival significantly. There was a trend towards better survival of surface FPDs over hybrid FPDs, but differences were not significant. Main failure modes were fracture of the FPD and delamination of veneering composite.SignificanceA success rate of 45% and a survival rate of 64% after 5 years was found. Fracture of the framework and delamination are the most prevalent failure modes, especially for surface FPDs.     

Direct and indirect fiber-reinforced fixed partial dentures: case reports.

Direct and indirect fiber-reinforced resin composite fixed partial dentures are a new way to produce minimally invasive, esthetic, and cost-effective metal-free tooth replacements. These treatment alternatives have a number of indications, for example, chairside tooth replacements, long-term provisional fixed partial dentures, economically feasible tooth replacements for patients who cannot afford more traditional treatment regimens, and tooth replacements for medically compromised patients who are unable to withstand the physical stress associated with fabrication of traditional fixed prostheses. This article presents four typical cases in which fiber-reinforced fixed partial dentures seemed to be the preferable treatment modality.