Fiber Reinforced Composites in Dentistry
Click HERE to see the Clinical Article on FRC
1. Freudenthaler, J.W., G.K. Tischler,
and C.J. Burstone, Bond strength of fiber-reinforced composite bars for
orthodontic attachment. Am J Orthod Dentofacial Orthop, 2001. 120(6): p.
648-653.
Long fiber-reinforced composites (FRC) have been shown to have enhanced
mechanical properties that allow their use in orthodontic applicances as bars
that join teeth to form either anchorage or active units. This study was
designed to determine if the bonding of an orthodontic attachment has sufficient
strength to withstand loading during clinical use. The experimental model
consisted of a hydroxyapatite stone that simulated enamel, FRC bars, and a
bonded metal hook. Three specimen types were compared:
(1) a metal hook-pad (the
control),
(2) a woven FRC with a hook-pad, and
(3) a unidirectional FRC with a
hook-pad. Loads were applied both parallel and at 90 degrees to the tooth
surface. Under no condition was the FRC pad combination weaker than the control
pad. Under some loading conditions, the loads before failure were as much as 3
times greater than those for the control. The lowest strength was found with
loads at 90 degrees to the tooth surface for all 3 types. Failure normally
occurred in the FRC and rarely at the bracket or tooth interface. The excellent
bonding of the orthodontic attachment to the FRC and the high strengths of the
FRC attachment combination demonstrate the ability to form connecting bars
between teeth for either anchorage or active segmental movements. These bars
offer advantages in simplicity in treatment by reducing the need for some bands,
attachments, or wires.
2. Terry, D.A., P.T. Triolo, Jr., and E.J. Swift, Jr., Fabrication of direct fiber-reinforced posts: a structural
design concept. J Esthet Restor Dent, 2001. 13(4): p. 228-40.
As the clinician continues the quest for optimal functional and esthetic success
of a tooth-restorative complex, the current selection of restorative materials
and techniques may prove overwhelming. Although no single system provides the
ideal restorative solution for every clinical circumstance, understanding of
general design criteria and the components for the various post and core systems
available allow the clinician to appropriately select the method and materials
compatible with the existing tooth structure and desired result. This article
provides a discussion of the various post and core systems, the methods and
materials inherent in these systems, and general design principles. Using that
basic information and clinical experience, the authors offer an alternative
procedure for the rehabilitation of the intraradicular anatomy of the post-endodontic
channel with a direct composite resin--the fiber-reinforced post and core
system. CLINICAL SIGNIFICANCE: Using improved restorative materials that
stimulate the physical properties and other characteristics of natural teeth in
combination with the proper design principles, the clinician can develop a
tooth-restorative complex with optimal functional and esthetic results.As the
clinician continues the quest for optimal functional and esthetic success of a
tooth-restorative complex, the current selection of restorative materials and
techniques may prove overwhelming. Although no single system provides the ideal
restorative solution for every clinical circumstance, understanding of general
design criteria and the components for the various post and core systems
available allow the clinician to appropriately select the method and materials
compatible with the existing tooth structure and desired result. This article
provides a discussion of the various post and core systems, the methods and
materials inherent in these systems, and general design principles. Using that
basic information and clinical experience, the authors offer an alternative
procedure for the rehabilitation of the intraradicular anatomy of the post-endodontic
channel with a direct composite resin--the fiber-reinforced post and core
system.
3. Ellakwa, A., et al., Influence of veneering composite composition on the efficacy of fiber- reinforced
restorations (FRR). Oper Dent, 2001. 26(5): p. 467-75.
This study investigated the influence of fiber reinforcement on the flexural
properties of four commercial (Artglass, Belleglass HP, Herculite XRV and
Solidex) veneering composites (Series A) and two experimental composites (Series
B&C). This study investigated how the composition of the veneering
composites influenced the enhancement of strength and modulus produced by fiber
reinforcement. The formulation of the experimental composites were varied by
changing the filler load (Series B) or the resin matrix chemistry (Series C) to
assess the effect these changes would have on the degree of reinforcement.
In Series A, the commercial veneering composites were reinforced by an
Ultra-High-Molecular-Weight Polyethylene fiber (UHMW-PE/Connect) to evaluate
flexural properties after 24 hours and six months. In Series B, experimental
composites with the same organic matrix but with different filler loads (40% to
80% by weight) were also reinforced by Connect fiber to evaluate flexural
properties. In Series C, experimental composites (Systems 1-4) with the same
filler load (76.5% by weight) but with different organic matrix compositions
were reinforced by Connect fiber to evaluate flexural properties. For Series B
and C, flexural properties were evaluated after 24 hours water storage.
All the samples were prepared in a mold 2 mm x 2 mm x 25 mm and stored in distilled
water at 37 degrees C until they were ready for flexural testing in an Instron
Universal Testing Machine using a crosshead speed of 1 mm/minute. The results
showed no significant differences in the flexural strength (FS) between any of
the commercial reinforced composites in Series A. The flexural modulus (FM) of
the fiber-reinforced Belleglass HP group was significantly higher than for
Artglass and Solidex.
Water storage for six months had no significant (p>0.05) effect on the flexural strength of three of the four reinforced
veneering composites. The flexural strength for Artglass was significantly
reduced (p0.05) by six-month water storage. In Series B, however, increasing the
amount of filler loading improved the flexural modulus of the reinforced
experimental composite but had no effect on its flexural strength. In Series C,
changing the organic matrix formulation had no affect on flexural strength but
affected the flexural modulus of the reinforced experimental composite.
4. Rosentritt, M., et al., In vitro
repair of three-unit fiber-reinforced composite FPDs. Int J Prosthodont, 2001. 14(4): p. 344-9.
PURPOSE: Clinical damage, such as the fracture or abrasion of composite veneers,
may cause the loss of a fixed partial denture (FPD). Intraoral methods may help
in repairing and therefore lengthening the life span of the restoration. The aim
of this in vitro study was to evaluate an intraoral method of repairing
fractured FPDs made of two different fiber-reinforced composite framework
systems.
MATERIALS AND METHODS: Shear bond strengths of a composite between two
different fiber- reinforced composite frameworks were determined after five
different mechanical surface treatments. A silicate-silane coating intraoral
air- abrading system provided the most reliable bond strength values and was
therefore used for treatment for the following veneer repair. The repair of 24
three-unit posterior FPDs was performed using a restorative composite resin. All
FPDs were examined after simulating clinical service using thermocycling and
mechanical loading. Fracture forces were determined for original FPDs and for
FPDs after simulated intraoral repair.
RESULTS: The fracture strength of all
original FPDs was about 900 N. After repair, a maximum decrease in strength of
about 15% was determined. FPDs that were extremely damaged by cutting the
framework showed the lowest results, with values of about 450 N.
CONCLUSION: The repair of the fractured veneer of fiber-reinforced composite FPDs provided good
results and therefore may lengthen the life span of damaged FPDs. The repair of
the fractured frameworks showed good results but can only be recommended for
limited temporary use.
5. Krasteva, K., Clinical application of a fiber-reinforced post system. J Endod, 2001. 27(2): p. 132-3.
The tooth structure of an endodontically treated tooth was restored with a core
on a post, both prefabricated with fiber-reinforced polymer- ceramic material
(Sculpture/FibreKor) and subsequently with a metal- free crown. The tooth
restoration is described in detail. It includes root canal preparation,
polyvinyl siloxane impression taking, laboratory fabrication of the core on the
post, adhesive cementation of the post-and-core system in the root canal,
fabrication and cementation of the restorations, adjustment, and finishing. The
success of this metal-free system is based on its increased flexural and tensile
strength. Its application is safe, effective, and reliable. The high- quality
aesthetics of the restorations is due to the translucency of the post-and-core
material.
6. Bacakova, L., et al., Polishing and coating carbon fiber-reinforced carbon composites with a carbon-titanium layer
enhances adhesion and growth of osteoblast-like MG63 cells and vascular smooth
muscle cells in vitro. J Biomed Mater Res, 2001. 54(4): p. 567-78.
Carbon fiber-reinforced carbon composites (CFRC) are considered to be promising
materials for orthopedic and dental surgery. Their mechanical properties can be
tailored to be similar to those of bone, and their chemical composition (close
to pure carbon) promises that they will be tolerated well by the surrounding
tissue.
In this study, CFRC composites were fabricated from phenolic resin and
unidirectionally oriented Torayca carbon fibers by carbonization (1000 degrees
C) and graphitization (2500 degrees C). The material then was cut with a diamond
saw into sheets of 8 x 10 x 3 mm, and the upper surface was polished by
colloidal SiO2 and/or covered with a carbon-titanium (C:Ti) layer (3.3 microm)
using the plasma-enhanced physical vapor deposition method.
Three different kinds of modified samples were prepared: polished only, covered only, and
polished + covered. Untreated samples served as a control. The surface roughness
of these samples, measured by a Talysurf profilometer, decreased significantly
after polishing but usually did not decrease after coating with a C:Ti layer. On
all three modified surfaces, human osteoblast-like cells of the MG63 line and
rat vascular smooth muscle cells (both cultured in a Dulbecco's minimum
essential medium with 10% fetal bovine serum) adhered at higher numbers (by
21-87% on day 1 after seeding) and exhibited a shorter population doubling time
(by 13-40%). On day 4 after seeding, these cells attained higher population
densities (by 61-378%), volume (by 18-37%), and protein content (by 16-120%).
These results were more pronounced in VSMC than in MG63 cells and in both groups
of C:Ti-covered samples than in the polished only samples. The release of carbon
particles from the CFRC composites was significantly decreased--by 8 times in
the polished only, 24 times in the covered only, and 42 times in the polished +
covered samples. These results show that both polishing and carbon- titanium
covering significantly improve the biocompatibility of CFRC composites in vitro,
especially when these two modifications are combined.
7. Tanner, J., P.K. Vallittu, and E.
Soderling, Effect of water storage of E-glass fiber-reinforced composite on
adhesion of Streptococcus mutans. Biomaterials, 2001. 22(12): p. 1613-8.
This study investigated the effect of water storage of fiber-reinforced
composite on the adhesion of Streptococcus mutans (S. mutans) and its ability to
stay adhered and multiply on the FRC. The materials (E-glass fibers and denture
base polymer) were stored in water for 14 or 30 days or left dry. Water contact
angles of the materials before and after water storage were determined. Test
specimens, with or without parotid saliva or serum pellicle, were incubated in a
suspension of S. mutans allowing initial adhesion to occur. Bacterial adhesion
and multiplication was studied using scanning electron microscopy. Contact
angles of both materials were significantly reduced after water storage
indicating an increase in surface free energy. When studied without a surface
pellicle, water storage significantly increased adhesion of S. mutans to both
glass and polymer. Saliva coating of the materials resulted in higher degree of
adhesion to glass fibers in comparison with polymer and after 14 days water
storage glass bound over twice as much S. mutans cells than the polymer matrix.
Bacterial growth and biofilm formation occurred equally on both materials.
RESULTS: The results of this in vitro study suggest that in order to avoid the possible
increase in S. mutans adhesion, the reinforcing glass fibers should be covered
with the matrix polymer of the composite.
8. Rifkin, R. and E.A. McLaren,
Restoring vertical dimension and facial harmony with the conservative use of
fiber-reinforced composite resin. Pract Proced Aesthet Dent, 2001. 13(3): p.
233-7.
9. Behr, M., et al., Comparison of three types of fiber-reinforced composite molar crowns on their fracture
resistance and marginal adaptation. J Dent, 2001. 29(3): p. 187-96.
Three types of fiber-reinforced composite (FRC) molar crowns were tested on
their fracture resistance and marginal adaptation under simulated oral stress
conditions. Two glass fiber systems, one processed with a vacuum/pressure
system, the other by manual fiber adaptation, and a polyethylene fiber system
were evaluated. Every group consisted of 12 crowns.All crowns were luted
adhesively on human molars and exposed to thermal cycling and mechanical loading
(TCML: 6000x5 degrees C/55 degrees C; 1.2x10(6)x50N; 1.66Hz).
The marginal adaptation was evaluated through dye-penetration and analyzed
semi-quantitatively with a scanning electron microscope. The fracture resistance
was measured using a Zwick universal testing machine.The highest fracture
resistance was observed on the glass-fiber systems (FibreKor/Sculpture
1875N+/-596; Vectris/Targis 1726+/-542), though statistically, the polyethylene
system (belleGlass/Connect 1388+/-620) was not significantly weaker.
All systems exceeded the fracture resistance required to withstand the maximum masticatory
forces expected in the molar region. The marginal adaptation generally had a
tendency towards larger gaps after TCML. The crown/composite-cement bond
deteriorated significantly after TCML with the manual fiber adaptation and the
polyethylene fiber system. The cement/tooth bond strength depended on which
composite-cement/dentin-adhesive system was used.
CONCLUSION: The fracture
resistance of molar crowns made of glass-fiber reinforced composite was higher
than those of polyethylene fiber-reinforced composite crowns. However, there was
no statistically significant difference. The marginal adaptation seems to depend
on the fiber systems and composite-cement/dentin adhesive system used.
10. Behr, M., et al., Glass
fiber-reinforced abutments for dental implants. A pilot study. Clin Oral
Implants Res, 2001. 12(2): p. 174-8.
Titanium abutments in dental implants shine through all-ceramic crowns and
therefore limit excellent esthetic results. Prototypes of tooth- colored
fiber-reinforced abutments were investigated to avoid the shining-through
effect. In vitro, the fracture strength was determined after thermal cycling and
mechanical loading of all-ceramic single crowns and four-unit bridges made of a
fiber-reinforced composite. The suprastructures were adhesively fixed onto
fiber-reinforced implant abutments and compared with those fixed on standard
titanium abutments. The median of the fracture strength of the
titanium-supported all- ceramic crowns was significantly higher than the median
of crowns fixed onto the prototypes. But this value was still more than twice as
high as the maximum loading force under oral conditions. No statistical
difference was found between four-unit bridges made by fiber-reinforced
composite inserted onto titanium abutments and those inserted onto
fiber-reinforced abutments. Fiber-reinforced abutment prototypes for dental
implants avoided the shining-through effect associated with metal abutments.
Their load-bearing capacity after in vitro stress simulation was higher than the
maximum oral loading force. With some improvements, the fiber-reinforced implant
abutments are therefore a promising alternative to titanium abutments.
11. Meiers, J.C. and M.A. Freilich,
Conservative anterior tooth replacement using fiber-reinforced composite. Oper
Dent, 2000. 25(3): p. 239-43.
12. Trushkowsky, R.D., Esthetic
posterior tooth replacement using a fiber reinforced bridge. Compend Contin Educ
Dent, 2000. 21(1): p. 80-4.
13. Shuman, I.E., Replacement of a
tooth with a fiber-reinforced direct bonded restoration. Gen Dent, 2000. 48(3):
p. 314-8.
Today's methods and materials for tooth replacement are multiple and varied.
Modern materials now allow for highly conservative abutment preparations that
can retain bonded single tooth replacement fixed prostheses. A case report is
presented in which fiber reinforced with composite resin was used for placement
of a three-unit fixed long-term provisional restoration, providing fracture
resistance while achieving an esthetically pleasing, durable restoration.
14. Giordano, R., 2nd, Fiber reinforced
composite resin systems. Gen Dent, 2000. 48(3): p. 244-9.
The Targis/Vectris and Sculpture/FibreKor systems were devised to create a
translucent maximally reinforced resin framework for fabrication of crowns,
bridges, inlays, and onlays. These materials are esthetic, have translucency
similar to castable glass-ceramics such as OPC and Empress, and have fits that
are reported to be acceptable in clinical and laboratory trials. These
restorations rely on proper bonding to the remaining tooth structure; therefore,
careful attention to detail must be paid to this part of the procedure.
Cementation procedures should involve silane treatment of the cleaned abraded
internal restoration surface, application of bonding agent to the restoration as
well as the etched/primed tooth, and finally use of a composite resin. Each
manufacturer has a recommended system which has been tested for success with its
resin system. These fiber reinforced resins are somewhat different than
classical composites, so not all cementation systems will necessarily work with
them. Polishing of the restoration can be accomplished using diamond or alumina
impregnated rubber wheels followed by diamond paste. The glass fibers can pose a
health risk. They are small enough to be inhaled and deposited in the lungs,
resulting in a silicosis-type problem. Therefore, if fibers are exposed and
ground on, it is extremely important to wear a mask. Also, the fibers can be a
skin irritant, so gloves also should be worn. If the fibers become exposed
intraorally, they can cause gingival inflammation and may attract plaque. The
fibers should be covered with additional composite resin. If this cannot be
accomplished, the restoration should be replaced. The bulk of these restorations
are formed using a particulate filled resin, similar in structure to
conventional composite resins. Therefore, concerns as to wear resistance, color
stability, excessive expansion/contraction, and sensitivity remain until these
materials are proven in long-term clinical trials. They do hold the promise of
minimizing tooth reduction and may be particularly useful in preserving sound
tooth structure. Although not the primary intended use, an excellent application
is long- term temporization, such as for patients requiring full mouth
rehabilitation. The belleGlass/Connect, Ribbond, and GlasSpan materials rely on
nonimpregnated polyethylene fibers which have mechanical properties inferior to
Vectris and FibreKor. These fibers may be used to greater success as splinting
materials, in provisional restorations, and in repair of complete and partial
removable dentures.
15. Vallittu, P.K. and C. Sevelius,
Resin-bonded, glass fiber-reinforced composite fixed partial dentures: a
clinical study. J Prosthet Dent, 2000. 84(4): p. 413-8.
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.
16. Duncan, J.P., M.A. Freilich, and C.J.
Latvis, Fiber-reinforced composite framework for implant-supported overdentures.
J Prosthet Dent, 2000. 84(2): p. 200-4.
This article presents a new method for fabricating a framework for an
implant-supported overdenture using unidirectional fiber-reinforced composite.
This procedure eliminates the need for a traditional metal alloy framework. The
fiber-reinforced composite framework has the advantages of lower cost, less time
and materials needed during fabrication, minimal potential for toxicity to the
technician and patient, and a more esthetic metal-free final result.
17. Hughes, T.E. and H.E. Strassler,
Minimizing excessive composite resin when fabricating fiber-reinforced splints.
J Am Dent Assoc, 2000. 131(7): p. 977-9.
18. Tanner, J., P.K. Vallittu, and E.
Soderling, Adherence of Streptococcus mutans to an E-glass fiber-reinforced
composite and conventional restorative materials used in prosthetic dentistry. J
Biomed Mater Res, 2000. 49(2): p. 250-6.
The adherence of Streptococcus mutans to E-glass used in fiber- reinforced
composites, denture base polymer, and four other restoratives was investigated.
The materials were studied with and without a parotid saliva and serum pellicle.
Specimens of the studied materials (E-glass, denture base polymer, titanium,
cobalt-chromium alloy, gold alloy, and grained feldspar ceramic) were incubated
in a suspension of S. mutans, allowing initial adhesion to occur. The degree of
bacterial adhesion was studied using scanning electron microscopy (SEM). The
studied uncoated materials showed rather similar adhesion of S. mutans. Saliva
coating resulted in a decrease of adherence to all materials except glass. With
a saliva pellicle E-glass showed the strongest ability to bind S. mutans, and it
differed significantly from the other studied materials. Serum coating markedly
decreased adhesion to all materials, and only minor differences among the
studied materials were observed. The results of this study suggest that the
studied restoratives are rather similar with respect to S. mutans adhesion and
that a saliva pellicle may promote adhesion of S. mutans to glass fibers.
19. Winters, K.L., Using a
fiber-reinforced ceromer for fixed restorations. Dent Today, 1999. 18(6): p.
70-3.
20. Lopez, L.A., A metal-free
fiber-reinforced replacement of a fractured tooth--a case report. Pract
Periodontics Aesthet Dent, 1999. 11(4): p. 508-10, 512, 517.
21. Gohring, T.N., W.H. Mormann, and
F. Lutz, Clinical and scanning electron microscopic evaluation of fiber-
reinforced inlay fixed partial dentures: preliminary results after one year. J
Prosthet Dent, 1999. 82(6): p. 662-8.
STATEMENT OF PROBLEM: Restorative dentistry searches for nonmetal reinforcement
of esthetic fixed partial dentures (FPDs). PURPOSE: This clinical study
evaluated conservative fiber-reinforced composite FPDs bonded to inlay
abutments. MATERIAL AND METHODS: Twenty fiber- reinforced composite inlay FPDs
were made for 15 patients. Restorations were manufactured with the Targis
Vectris glass-fiber-reinforced composite system and a simplified laboratory
technique. The 20 bonded inlay FPDs were examined clinically and by SEM after 1
year. RESULTS: All 20 FPDs were intact at the 1-year examination. There were no
signs of fracture, surface defects, or excessive wear with SEM. SEM marginal
analysis exhibited 91.6% +/- 5% excellent margins at the tooth-luting composite
interface and 86. 1% +/- 8% excellent margins at luting composite/restoration
interface. CONCLUSION: On the basis of the results of this descriptive study,
bonded glass-fiber-reinforced composite inlay FPDs were considered clinically
successful at the 1- year examination.
22. Arbogast, K.B. and S.S. Margulies, A
fiber-reinforced composite model of the viscoelastic behavior of the brainstem
in shear. J Biomech, 1999. 32(8): p. 865-70.
Brainstem trauma occurs frequently in severe head injury, often resulting in
fatal lesions due to importance of brainstem in crucial neural functions.
Structurally, the brainstem is composed of bundles of axonal fibers distinctly
oriented in a longitudinal direction surrounded by an extracellular matrix. We
hypothesize that the oriented structure and architecture of the brainstem
dictates this mechanical response and results in its selective vulnerability in
rotational loading. In order to understand the relationship between the biologic
architecture and the mechanical response and provide further insight into the
high vulnerability of this region, a structural and mathematical model was
created. A fiber-reinforced composite model composed of viscoelastic fibers
surrounded by a viscoelastic matrix was used to relate the biological
architecture of the brainstem to its anisotropic mechanical response. Relevant
model parameters measured include the brainstem's composite complex moduli and
relative fraction of matrix and fiber. The model predicted that the fiber
component is three times stiffer and more viscous than the matrix. The fiber
modulus predictions were compared with experimental tissue measurements. The
optic nerve, a bundle of tightly packed longitudinally arranged myelinated
fibers with little matrix, served as a surrogate for the brainstem fiber
component. Model predictions agreed with experimental measures, offering a
validation of the model. This approach provided an understanding of the
relationship between the specific biologic architecture of the brainstem and the
anisotropic mechanical response and allowed insight into reasons for the
selective vulnerability of this region in rotational head injury.
23. Gohring, T.N., I. Krejci, and F.
Lutz, [Resin-bonded inlay bridges made of glass-fiber-reinforced composites. A
step-by-step description of their clinical use]. Schweiz Monatsschr Zahnmed,
1999. 109(4): p. 368-84.
24. Waltimo, T., et al., Adherence of
Candida albicans to the surface of polymethylmethacrylate-- E glass fiber
composite used in dentures. Int J Prosthodont, 1999. 12(1): p. 83-6.
PURPOSE: The use of reinforcing fibers in dentures has raised concerns about
possible increased adherence of yeasts to the surface. The aim of this in vitro
study was to compare the adherence of Candida albicans to the surface of
denture-base polymer and to E-glass fibers. MATERIALS AND METHODS: Test
specimens were made from an autopolymerized denture- base resin (Palapress)
reinforced with preimpregnated unidirectional E- glass fibers, which were
exposed at the surface. The test specimens were pretreated with parotid saliva
and incubated without agitation in standardized yeast suspensions (10(8)
colony-forming units per mL) in phosphate-buffered saline at 37 degrees C for 1
hour. The test specimens were then washed to remove nonadherent cells. After
being air dried, they were sputter coated with gold-palladium for scanning
electron microscopy (SEM). To compare the adherence to different surfaces, the
number of yeast cells found either on the polymer matrix or on the glass fibers
was counted from SEM fields (170 microns x 120 microns, 600 x) of randomly
selected areas. RESULTS: The mean density of yeast cell found on the surface of
the polymer matrix was significantly higher (P 0.001) than that on the surface
of glass fibers. The number of adherent yeast cells found at the interface
between the fibers and polymer matrix was high. CONCLUSION: The adherence of C
albicans to E-glass fibers was lower than to polymer matrix in the denture
composite. If fibers are exposed only during polishing of the composite, the
reinforcing material appears not to increase the adherence of this common oral
yeast. However, areas with permanently exposed fibers may provide mechanical
retention for yeast cells at the interface of the components.
25. Goldberg, A.J. and M.A. Freilich, An
innovative pre-impregnated glass fiber for reinforcing composites. Dent Clin
North Am, 1999. 43(1): p. 127-33, vi-vii.
This article summarizes the development of pre-impregnated, fiber- reinforced
composites. Previous efforts with various reinforcement materials for splinting
are cited. The benefits of pre-impregnation are explained. The clinical
procedure for placing a fiber-reinforced composite splint is described.
26. Rudo, D.N. and V.M. Karbhari,
Physical behaviors of fiber reinforcement as applied to tooth stabilization.
Dent Clin North Am, 1999. 43(1): p. 7-35, v.
This article presents an understanding of the mechanical response of polymer
matrix composite materials that are reinforced with fibers that have high levels
of failure strain. Also discussed are the basic principles for the use of the
materials and techniques to optimize the clinical success for the applications
in which these fibers are used to restore and maintain form and function to the
masticatory structures.
27. Freilich, M.A., et al.,
Preimpregnated, fiber-reinforced prostheses. Part I. Basic rationale and
complete-coverage and intracoronal fixed partial denture designs. Quintessence
Int, 1998. 29(11): p. 689-96.
This is the first of two articles describing the development and use of a
continuous fiber-reinforced composite as a framework for the fabrication of
fixed partial dentures and splints. The chemical composition and physical
structure of the fiber-reinforced composite, along with the progression and
development of a variety of fiber- reinforced composite materials, are
discussed. Criteria for case selection, tooth preparation, and the clinical and
laboratory procedures required for partial- or complete-coverage fixed partial
denture fabrication and delivery are described.
28. Meiers, J.C., et al., Preimpregnated,
fiber-reinforced prostheses. Part II. Direct applications: splints and fixed
partial dentures. Quintessence Int, 1998. 29(12): p. 761-8.
This article is the second in a series that describes the development, physical
properties, and clinical applications of fiber-reinforced composite materials.
The development of fiber-reinforced composite technology has opened new avenues
for fabricating direct tooth replacements and splints that are esthetic and
simple in design and execution and have the potential for excellent durability.
Splinting techniques for hypermobile dentitions or postorthodontic retention and
the replacement of anterior and posterior teeth using a groove preparation, a
denture tooth, and a fiber-reinforced composite framework will be described.
29. Belvedere, P.C., Single-sitting,
fiber-reinforced fixed bridges for the missing lateral or central incisors in
adolescent patients. Dent Clin North Am, 1998. 42(4): p. 665-82, ix.
Many materials, methods, and techniques for the reinforcing of composites to
bond a pontic onto abutment teeth have been tried and promoted. In this article,
the author examines the use of fiber reinforcement in fixed bridges, describing
the various steps performed by the dentist during the procedure.
30. Vallittu, P.K., Compositional and
weave pattern analyses of glass fibers in dental polymer fiber composites. J
Prosthodont, 1998. 7(3): p. 170-6.
PURPOSE: This study compared weave patterns and glass compositions of five glass
fiber materials found in commercial fiber-reinforced dental composites.
MATERIALS AND METHODS: A scanning electron microscope (SEM) was used to
investigate the woven structure of five glass fiber products, and an energy-dispersive
x-ray spectrometer (SEM/EDS) was used to determine the elemental composition of
these glass fibers in the bulk and at the surface of the fiber. Five fibers of
each product were analyzed. RESULTS: The fiber products were either
unidirectional rovings or bidirectional weaves. More precisely, the woven
structures were linen weave, twill weave, or twill weave ribbon. SEM/EDS
analysis revealed that the composition of the glass fibers was typical for E
(electrical)-glass fibers with one exception. One product intended for use in
fixed prosthodontics included unidirectional fibers with a composition
consistent with a modified high-tensile-strength R-glass. Boron oxide found on
the surface of glass fibers would likely contribute to an increased potential
for corrosion of fiber-reinforced composite. CONCLUSIONS: The predominant fiber
composition in these products is E-glass. Because the degree of hydrolytic
stability of polymer-fiber composites over time may lead to material failure in
permanent restorations, this property should be investigated further.
31. Lopez, L.A., Restoration without
compromise: using a fiber-reinforced polyceramic composite system to replace
missing teeth. Dent Today, 1998. 17(4): p. 96-9.
32. Kettunen, J., et al., The effect
of an intramedullary carbon-fiber-reinforced liquid crystalline polymer implant
on bone: an experimental study on rabbits. J Biomed Mater Res, 1998. 42(3): p.
407-11.
A novel composite material with an ultra-high strength and a low elastic modulus
called carbon-fiber-reinforced liquid crystalline polymer (LCP/CF) has been
developed. We studied the effects of an intramedullary LCP/CF rod on bone in
rabbits. A LCP/CF rod of 3.2 mm in diameter and 50 mm in length was introduced
into the intramedullary canal of the right femur in ten rabbits weighing an
average of 3.6 (3.1- 4.2) kg. The follow-up intervals were 3 and 52 weeks. No
signs of deformity or osteopenia were seen in the operated femurs in the
radiographic, histological, and histomorphometric studies. Histologically, the
implant was enclosed by cancellous bone in the metaphyseal area and by a thin
cancellous bone cuff in medullary cavity. Bone was able to grow in direct
contact with the LCP/CF rod. No signs of degradation of the implants or of
adverse tissue reaction were seen. The intramedullary LCP/CF rod had no harmful
effects on bone in rabbits. The biocompatibility of the LCP/CF appeared to be
good. This novel composite material demonstrates properties that may be useful
in orthopedic applications.
33. Freilich, M.A., et al., Development
and clinical applications of a light-polymerized fiber- reinforced composite. J
Prosthet Dent, 1998. 80(3): p. 311-8.
STATEMENT OF PROBLEM: After 0 years of intermittent reports in the literature,
the use of fiber reinforcement is just now experiencing rapid expansion in
dentistry. PURPOSE: This article describes the development and use of a
continuous, unidirectional fiber reinforced composite as a framework for the
fabrication of fixed prostheses. METHODS: By using various matrix materials and
fibers, a number of fiber-reinforced composite formulations were evaluated with
the goal of creating a system with optimized mechanical properties and handling
characteristics. Fiber-reinforced composite based on a light polymerized BIS-GMA
matrix has been used clinically to make 2-phase prostheses comprised of an
internal glass fiber-reinforced composite substructure covered by a particulate
composite. The clinical and laboratory procedures required for the fabrication
and use of reinforced composite fixed prostheses are described for laboratory-
fabricated complete or partial coverage fixed prosthesis and chairside
prosthesis. RESULTS: Although additional clinical experience is needed,
fiber-reinforced composite materials can be used to make metal-free prostheses
with excellent esthetic qualities.
34. Vallittu, P.K., I.E. Ruyter, and K.
Ekstrand, Effect of water storage on the flexural properties of E-glass and
silica fiber acrylic resin composite. Int J Prosthodont, 1998. 11(4): p. 340-50.
PURPOSE: The aim of this study was to determine the effect of water on the
flexural properties of fiber-reinforced denture base polymers. MATERIALS AND
METHODS: Continuous woven silanized electrical glass, or E-glass, fibers and
woven silica fibers were used to reinforce heat- cured and autopolymerized
denture base polymers. Fibers were oriented at a 45-degree angle to the long
axis of the test specimens. Control specimens were unreinforced. Dry test
specimens and those stored in water for up to 48 weeks were tested with a
three-point loading apparatus. The surfaces of the fibers of the test specimens
stored dry or 48 weeks in water were analyzed with a scanning electron
microscope to evaluate the degree of adhesion between fibers and polymer matrix.
RESULTS: The ultimate transverse strength of unreinforced and reinforced denture
base polymers decreased during 48 weeks' storage in water (P 0.05, one-way
analysis of variance, n = 5), and most of this reduction occurred during the
first 4 weeks of storage in water. The flexural modulus of the unreinforced test
specimens decreased significantly (P 0.001), whereas there was less, if any,
change in the flexural modulus of the fiber-reinforced test specimens. Scanning
electron microscopic examination revealed no differences in adhesion of E-glass
fibers to the polymer matrix when the specimens stored in water were compared
with those stored by. Reduced adhesion between the silica fibers and matrix was
observed after 48 weeks' storage in water. CONCLUSION: The results of this study
suggest that the ultimate transverse strength of the E-glass fiber-reinforced
test specimens decreased 14% and that of the silica fiber-reinforced test
specimens decreased 36% after 48 weeks of storage in water.
35. Trinkner, T.F. and M. Roberts,
Aesthetic restoration with full-coverage porcelain veneers and a Ceromer/fiber-reinforced
composite framework: a case report. Pract Periodontics Aesthet Dent, 1998.
10(5): p. 547-54; quiz 556.
Due to the recent evolution of dental materials and procedures, the restoration
of a particular clinical condition can be accomplished by various alternatives.
While the use of integrated treatment modalities permit the restoration team to
utilize the benefits of each material simultaneously, it requires the
development of a comprehensive preoperative treatment plan to address the
specific concerns of each region or material utilized. This article describes
the use of a multidisciplinary approach to restore proper occlusion, function,
and aesthetics in a patient with worn dentition.
36. Blitz, N., Adaptation of a
fiber-reinforced restorative system to the rehabilitation of endodontically
treated teeth. Pract Periodontics Aesthet Dent, 1998. 10(2): p. 191-3.
37. Rosentritt, M., et al., Intraoral
repair of fiber-reinforced composite fixed partial dentures. J Prosthet Dent,
1998. 79(4): p. 393-8.
STATEMENT OF THE PROBLEM: Fractured composite facings may result in
replacement of a fixed partial denture unless a reliable intraoral repair method
can be provided. PURPOSE: This in vitro study tested the quality of an intraoral
repair method for fractured facings of fixed partial dentures made of a
fiber-reinforced composite system. MATERIAL AND METHODS: Shear bond strengths of
a light-curing composite to a fiber-reinforced composite material were
determined after different mechanical surface treatments. Aluminum oxide air
abrading provided the most reliable bond strength values and therefore was used
as a pretreatment for the facing repair of three-unit posterior fixed partial
dentures. Facing repair was performed with the tested light- curing hybrid
composite. Facing fracture strengths of repaired and original fixed partial
dentures were determined after thermocycling and mechanical loading. RESULTS:
Median facing fracture strength of the original fixed partial dentures was 1450
N after a simulated clinical service of 5 years. Facing fracture strengths of
the repaired fixed partial dentures were significantly lower compared with the
control group after an additional simulated 2-year interval. However, the median
fracture force was still 1000 N. CONCLUSIONS: The facing repair of a
fiber-reinforced fixed partial denture with a hybrid composite in combination
with aluminum oxide air-abrading pretreatment and silanization provided
sufficient fracture strength. Therefore the replacement of the complete
restoration may be avoided.
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