ertugrul et al 34568

7/27/2019 Ertugrul Et Al 34568

http://slidepdf.com/reader/full/ertugrul-et-al-34568 1/7

An in vitro comparison of cast metal dowel retention using various lutingagents and tensile loading

H. Zeynep Ertugrul, DDS, PhD,a and Yahia H. Ismail, DMD, MS, PhDb

School of Dental Medicine, Department of Prosthodontics, University of Pittsburgh, Pittsburgh, Pa

Statement of problem. No clear consensus exists regarding the choice of luting agents for the retention of cast metal dowels used as a treatment alternative for endodontically treated teeth with excessive loss of coronaltooth structure.

Purpose. The purpose of this in vitro study was to investigate the retention of the dowel/luting agent/toothcomplex while applying different luting agents to cast metal dowels under vertical tensile loading.

Material and methods. Sixty extracted, noncarious mandibular premolars with roots of approximately 15-mm length were selected. For each tooth, a tapered root canal preparation was completed to a maximumdiameter of 1.60 mm and a length of 11 mm, a common clinical configuration to accommodate cast metaldowels. Sixty cast metal dowels were fabricated for the tooth specimens and cemented with 1 of 3 luting agents(n = 20): zinc-phosphate cement (ZPC) as a control, phosphate-methacrylate resin luting agent (PMRL,Panavia F), and phosphate-methacrylate resin luting agent with metal dowel surfaces modified with a silanecoating technique (PMRLS, Panavia F 1 Siloc). Tensile bond strength (TBS) of the specimens was measured

with a universal testing machine at a crosshead speed of 0.5 mm/min. Data (kg) were statistically analyzed using a

1-way analysis of variance and a Scheffe multiple range test (a

=.05). The homogeneity of variances was analyzedusing the Levene test.

Results. The TBS values of ZPC (34.2 6 10.54 kg) were significantly higher than PMRL (22 6 9.57 kg) andPMRLS (21.76 7.64 kg). There was no significant difference between the PMRL and PMRLS groups.

Conclusion. Within the limitations of this study, the use of zinc-phosphate cement provided greater TBS for castmetal dowels than the resin luting agent with and without the silane coating technique. The TBS values with and

without the silane coating technique were not statistically different. (J Prosthet Dent 2005;93:446-52.)

CLINICAL IMPLICATIONS

The use of cast metal dowels is common in restorative dentistry. This study demonstrated that

zinc-phosphate cement can provide superior retention for cast metal dowels relative to the phosphate-methacrylate resin luting agent with or without the silane coating technique.Consequently, practitioners may opt to choose zinc-phosphate cement over the other materials

tested when providing this treatment.

The successful restoration of an endodontically treated tooth is an ongoing challenge for a restorativedentist.1-3 Cast metal dowels are used as a methodfor dowel-and-core fabrication, and have been used toprovide long-term tooth structure replacement for

endodontically treated teeth with moderate to severedamage.4,5 Cast dowels are best used for single-rootedteeth and may be fabricated directly or indirectly.4-6

The retention of a dowel in a root is critical for thelongevity and success of this treatment. Studies havereported that design, length, and character of the surfaceof endodontic dow els have an influence on theirretentive properties.2-4,7 Furthermore, the ability of

a luting agent to retain a dowel can affect the prognosisof a restoration.4,7 All dowels gain their definitive reten-tion by cementation into a prepared root.2,8-10

Currently, a large variety of luting agents are availablefor this purpose. Studies have provided conflicting re-

sults in regard to the performance of different types of luting agents in retaining dowels.1,2,7,8,10-14 The ability of different luting agents to retain dental dowels is re-lated to the mechanical properties and durability of a lut-ing agent, the bonding ability of a luting agent to thesurfaces being joined, and the configuration of a doweland prepared canal.2,15-17

The luting agents currently available for dentalrestoration are zinc-phosphate, polycarboxylate, glassionomer, resin-modified glass ionomer, compomer,and adhesive resin cements.4,18 Morgano andBrackett4 showed that there are distinct advantages

and inherent disadvantages for each material category.

aPostgraduate Fellow.b

Professor and Director, Prosthodontic Residency Program.

446 THE JOURNAL OF PROSTHETIC DENTISTRY VOLUME 93 NUMBER 5

http://-/?-

http://-/?-

http://-/?-

http://-/?-



The authors reported that polycarboxylate and glass-ionomer cements provide a weak chemical bond to den-tin. Polycarboxylate cements have been reported toundergo plastic deformation after cyclic loading andmay be less retenti ve than zinc-phosphate and glass-ionomer cements.4 Glass-ionomer cements are knownto require several days and even several weeks to reachmaximum strength, making this choice unsuitable asa cement for dowels.4,7 Resin-modified glass-ionomercements, although suggested for cementation of dow-els, can imbibe water and expand with time.4 Zinc-phos-phate cement has been the gold standard luting agentfor decades. However, resin luting agents have alsobeen studied extensively, and several investigations

have evaluated the retention of interradicular dowelsusing adhesive resins.1,4,7-10,19 Some studies demon-strated that adhesive resin luting agents are more reten-tive than zinc-phosphate cement for dowels.2,7,11,14,20

Howe ver, other studies have demonstrated conflictingresults8,10,13,21 based on shrinkage stress and the diffi-culty in manipulating a phosphate-methacrylate resinluting agent. Shrinkage stress results in debonding of the luting agent from dentin and a tendency of thebonding of phosphate-methacrylate resin cement tofail in the root canal.10 Additionally, difficulty in manip-ulation, which results in the premature polymerization

of the phosphate-methacrylate resin luting agent, canprevent a complete seating of dowels into root canals.8

In the dowel–luting agent–tooth complex, there areseveral regions that may be a weak link in the outcomeof treatment, depending on the luting agent used.These regions include the luting agent–dentin interface,the dentin, and the luting agent–metal interf ace.1 Withrespect to the luting agent–metal interface,1,22 metalsurfaces may be altered in a variety of ways to improveadhesion, including airborne-particle abrasion, etching,and silane coating.1,22-26 The silane coating techniquehas been used for both noble and base alloys23,25-32

and has also been proposed for use in combination

with phosphate-methacrylate resin luting agents.22,28,32,33

This technique pyrolytically applies a silica bonding layerto the surface of a metal. A bifunctional silane-couplingagent, which bonds the silanol groups of a silica layer with the monomers of acrylic resin, is then added toenhance bonding between the resin and metal sur-

face.

12,27,34

It was reported that a strong chemicalbond is produced between metal and resin as a resultof the silica-silane bond that promotes adhesion.22,26-29,33 However, other studies indicate decreased11,12,23

or unchanged bond strengths of adhesive resin lutingagents with base metal alloys when used with silane coat-ing.12,28,31 A silane coating technique (Siloc) has beenrecently developed to simplify the regimen.34-36 It isalso applicable to both noble and base alloys and isused to provide a chemical bond between the silica layerscoated to an airborne-particle–abraded metal surfaceand a resin composite.34-41 Limited information is avail-able about the bond strength of cast base metal dowels with a silane coating surface treatment. The objectiveof this in vitro study was to compare the retentionof cast metal dowels when cemented with a zinc-phosphate, a phosphate-methacrylate, and a phosphate-methacrylate resin luting agent together with a recently developed silane coating metal surface treatmenttechnique.

MATERIAL AND METHODS

Sixty mandibular, noncarious premolars with rootlengths of approximately 15 mm were selected for this

study. Specimens were extracted within the last 6months due to periodontal involvement. Teeth werestored in a 0.1% M NaCl (0.9%) isotonic sodium chlo-ride solution at 22°C. The crowns were separated fromthe roots 1 mm above the cementoenamel junction with a diamond-coated disk (Superflex; Edenta AGDentalprodukte, Au/SG, Switzerland) under constant water spray. Root canals were widened using taperedburs (Lindemann; Edenta AG Dentalprodukte) with11-mm-long cutting surfaces that provided a continu-ous, uninterrupted taper from theapical end of the prep-aration with a 0.5-mm diameter to the coronal 1.6-mm

diameter opening. Root specimens were chosen fromthe set of 60, and the canals were lubricated withpetrolatum. For a single specimen, a solid plastic sprue(Williams Sprues; Williams Dental, Amherst, NY) wastrimmed so that it could easily slide into thecanal. Blue inlay wax (Blue regular inlay wax; HeraeusKulzer, Hanau, Germany) was introduced into the canalfollowed by the sprue to register the morphology of theroot canal. A rubber loop was placed at the end of thesprue to allow attachment to the tensile testing appara-tus. Another sprue was attached to the opposite side of the rubber loop so it was parallel to the sprue located

in the root. These 2 sprues and the rubber loop were

Fig. 1. Cast metal dowel and core.

THE JOURNAL OF PROSTHETIC DENTISTRYERTUGRUL AND ISMAIL

MAY 2005 447



aligned so that the sprues and the center of the loop wereparallel. Finally, a pattern was obtained that was com-posed of a dowel and rubber loop. This pattern was du-plicated with acrylic resin (Palavit G; Heraeus Kulzer) ina flask. After all specimens were fabricated, this proce-dure resulted in 60 dowel acrylic resin patterns, each with a loop and sprue. The dowels were evaluated forfit in all 60 prepared teeth. The canals were lubricated with petrolatum. The coronal aspects were recon-structed by applying the same acrylic resin with a brush. After the acrylic resin had polymerized, the patterns were removed from the roots. Blue inlay wax was placedin the voids, and the pattern was reinserted in the root.This procedure was repeated until the dowel pattern wassatisfactory. Afterwards, the coronal foundation wasshaped to a 4-mm height and a 3.7-mm diameter of acrylic resin. In consideration of the shrinkage of acrylicresin, the preparation depth was marked on the taperedbur (Lindemann; Edenta AG Dentalprodukte) to verify that the dowel was as long as the dowel space. This

length was then compared with the length of the dowelsto ensure that shrinkage was not a limitation of thisstudy. The acrylic resin specimens, ready for casting, were placed into a metal casting ring (Whip Mix,Louisville, Ky). The investment (Bellavest T; BEGO,Bremen, Germany) was prepared using a vacuum mixer(Motava SL; BEGO) and poured into a casting ring. Thespecimens were cast using an induction casting machine(Fornax 35K-F; BEGO). A metal alloy composed of 61.3% Ni, 26% Cr, and 11% Mo (Kera N; EisenbacherDentalwaren, Oben, Germany) was used for casting be-cause adhesive resins show higher bond strengths to

base metals relative to high noble and noble metal al-loys.1,23,26 Additionally, the manufacturer of Panavia F(Panavia F; Kuraray, Osaka, Japan) luting agentpurported that this material would adhere to Ni-Cr al-loys. Ni-Cr alloys with silica coating surface treatmentsystems have also been recommended for improvingbonding strength with adhesives.22,26,29-33,38 After thecasting was completed, all castings were allowed tocool to room temperature, and the investment material was removed from castings by airborne-particle abrasion with aluminum oxide (250 mm). The fit of the dowelcores in the teeth was evaluated with light finger pres-

sure, and the cast metal dowel cores were airborne-

particle abraded with 250-mm aluminum oxide forcomplete seating in the root canals (Fig. 1). The grainsize of 250 mm was chosen because it has been foundto produce an optimal surface for allowing a strongbond of the base metal alloy to the silane-coatedlayer.27,28

Retentive notches were placed on the outer surfacesof the roots with an inverted cone carbide bar (Lot05151197; Diatech Dental, Heerbrugg, Switzerland). A mixture of autopolymerizing acrylic resin (Tru-Kit;Harry Bosworth, Skokie, Ill) was poured into rectangu-lar boxes with dimensions of 33232cmtoformasolidblock to hold the roots during testing. Cast metal doweland cores seated in the prepared canal were then embed-ded into the acrylic resin in the boxes at the level of a ce-mentoenamel junction while the upper sprue waslocated in a surveyor (BEGO). The surveyor was usedto embed the specimens perpendicular to the base of the boxes to ensure tensile loading occurred along thelong axis of the root canal. These 60 standardized speci-

mens were then assigned to 3 groups of 20 specimenseach to accept a variable luting regimen. Before dowelcementation, the root canals were etched with 35%phosphoric acid gel (K Etchant; Kuraray) for 15 sec-onds, rinsed with water spray for 2 minutes, and dried with cotton paper points. The metal surfaces wererinsed with water and dried with compressed air beforecementation.

For the control group (ZPC), a zinc-phosphatecement (Harvard; Herstellungs-und ertriebsgesellschaftRichter & Hoffmann Harvard Dental, Berlin,Germany), in the proportion 1.5/1 g/mL, was mixed

on a clean glass slab for 1.3 minutes at 20°C. Then,zinc-phosphate cement was applied to the dowels witha plastic instrument, and the dowels were inserted intothe roots. Next, a 5-kg constant load was applied tothe specimens for 10 minutes until the cement set.15

Finally, excess cement was removed, and each specimen was cleaned with a moist cotton roll.

In the second group (PMRL Group), a phosphate-methacrylate resin luting agent (Panavia F; Kuraray) was prepared according to the manufacturer’s recom-mendations. Equal amounts of self-etching primer(Panavia F ED primer; Kuraray) liquids A (2-hydroxy-

ethyl methacrylate [HEMA], N-methacryloyl

Table I. Materials used in this study

Composition Brand name Manufacturer

Zinc-phosphate cement Harvard Richter & Hoffmann Harvard Dental, Berlin, Germany

Phosphate-methacrylate cement Panavia F Kuraray, Osaka, Japan

Silane metal surface conditioning system Siloc Heraeus Kulzer, Hanau, Germany

Dowel metal (61.3% Ni, 26% Cr, 11% Mo,

1.5% Si, 0.1% Mn, 0.03% C)

Kera N Eisenbacher Dentalware, Oben, Germany

THE JOURNAL OF PROSTHETIC DENTISTRY ERTUGRUL AND ISMAIL

448 VOLUME 93 NUMBER 5



5-aminosalicylic acid [5-NMSA], 10-methacryloxydecyldihydrogen phosphate [MDP]) and B (5-NMSA) weremixed together in a mixing dish, applied with a brushinside the canal, and allowed to stand for 60 seconds.Excess liquid was eliminated with a paper point beforecompletely drying the primer with a gentle air flow todelay the polymerization process. Equal amounts of the phosphate-methacrylate (Panavia F) paste A (MDP, bisphenol-A-glycidyldimethacrylate [Bis-GMA],filler, benzoyl peroxide, and photoinitiator) and B(Bis-GMA, filler, sodium fluoride, and amine) werethen mixed for 20 seconds on the mixing plate and ap-plied with a brush to the dowel. The dowel, covered with cement, was inserted into the root canal. A 5-kg

constant load was applied to the specimens. The excesscement at the margins was light-polymerized for 2 sec-onds with conventional halogen by means of a light(Translux EC; Heraeus Kulzer) for easy cleanup, and re-moved with an explorer. The antioxidizing agentsupplied with the material was applied to the marginsof the specimens.

In the third group (PMRLS Group), a surface condi-tioning procedure involving the use of methacryloxy-propyl trimethoxysilane (Siloc; Heraeus Kulzer) wasused. This system was recently developed b y the manu-facturer from the classical Silicoater system.35,36,38 This

procedure is recommended by the manufacturer foruse with all metals and has also been investigated with adhesive luting agents23,26,32 such as phosphate-methacrylate monomers.11,12,22,25,28 Siloc Pre material,purported to be an SiO2-reinforced polymer bond layerby the manufacturer, was first applied uniformly witha disposable brush on the cast metal dowel surfacesand allowed to dry for 2 minutes. Then specimens were placed in a ceramic holder inside the silanizationunit (Siloc oven), and Siloc Pre on the dowel surfaces was activated at 300°C for 6 minutes. Specimens wereallowed to cool to room temperature for 4 minutes after

the Siloc Pre activation. Siloc bond, as the silane cou-

pling agent, was applied uniformly with a disposablebrush on the activated dowel surfaces and allowed toair dry for 5 minutes. When the application of Siloc was completed, Panavia F primer and paste were appliedas previously described for the PMRL Group. After al-lowing an hour for the cementation, the specimens were returned to the isotonic NaCl solution for 15days at 22°C. The composition, brand name, and man-ufacturer for the 3 luting materials and casting alloy arelisted in Table I.

Each acrylic resin block was mounted firmly to thelower jaw of a universal testing machine (Lloyd EZ50;Lloyd Instruments, Hampshire, England). The uppersprue portion of the casting was connected to the upper

member of the testing machine. The prepared speci-mens were subjected to tensile forces along the longaxes of the dowel and tooth at a crosshead speed of 0.5 mm per minute. The force required to dislodgeeach dowel was recorded in kilograms. For each of thegroups, the mean, SD, SE, and minimum and maximum values were calculated according to the data outputobtained from the universal testing machine.

The force values (kg) were recorded when separation was observed in the universal testing machine. Statisticalanalysis was performed using 1-way analysis of variance(ANOVA), the homogeneity of variances was evaluated

using the Levene test, and paired comparisons of thegroups were performed using the Scheffe test.Differences were considered significant at a=.05.

RESULTS

According to the test results (Tables II and III), thedifference between the second and third groups wasnot significant. Although the retentive strength of thephosphate-methacrylate resin luting agent (Panavia F) was found not to be significantly different than thatof phosphate-methacrylate resin luting agent with

metal dowel surfaces modified by silane coating

Table II. Statistical values of experimental data (n = 20)

Mean (kg) SD SE Minimum value Maximum value

Zinc-phosphate cement (Harvard) 34.25 10.54 10.78 10.98 52.09

Phosphate-methacrylate resin luting agent (Panavia F) 22.09 9.57 6.86 7.01 39.33

Phosphate-methacrylate resin luting agent 1 surface

conditioning treatment (Siloc1 Panavia F)

21.75 7.64 7.35 10.26 42.21

Table III. One-way ANOVA

Source df Sum of squares Mean square F ratio F probability

Between groups 2 1996.6312 998.3156 11.3284 .0001

Within groups 55 4846.8572 88.1247

Total 57 6843.4885

df , Degrees of freedom.


MAY 2005 449



(Siloc1 Panavia F), the latter resulted in a slightly lowermean value. However, the tensile bond strength of zinc-phosphate cement was found to be significantly higherthan the specimens cemented with phosphate-methac-rylate resin luting agent (P ,.05).

DISCUSSION

Although the mode of failure measured in this inves-tigation may not directly correspond to the clinical sce-nario, standardized tensile strength tests are an acceptedmeasure of retentive values for luting agents used witha cement-root-dowel interface.1,2,7-11,14,15,20 For thisreason, tensile strength testing was used in this study.The phosphate-methacrylate resin luting agent(Panavia F), which was also used as an adhesive resin lut-ing agent in the present study, is commonly used forbonding cast alloys to tooth structureand has beenshownto bond to both airborne-particleabradedbase metal alloysand noble alloys.

In the studies concerning the bond strength of thisluting agent, higher bond strengths were observ ed forbase metal alloys than for noble metal alloys.1,22,33

This luting agent differs from existing resin com-posites, such as conventional resin luting agents, inthat a phosphate ester has been added to the monomerto create a dental adhesive using both mechanical andchemical bonding.12,18,19,24 This phosphoric-acid typeof monomer is adhesive to the oxide layer of base metalsand plays an important role in the metal-resin bond.22,23

The phosphate-methacrylate luting agent is also recom-

mended for usewith silane-coated base metal alloys.22,32Contrary to the present study, some studies have re-

ported significantly greater retention for cast metal dow-els cemented with phosphate-methacrylate lutingagents2,8,9,11 as opposed to zinc-phosphate cement when comparing tensile forces. For example, Chan et al2

compared the vertical retention of various lutingagents, including zinc-phosphate and phosphate-methacrylate monomer luting agents, with stainless steeldowels and obtained higher resistance to dislodgementby vertical tensile forces for Panavia than for zinc-phosphate cement.

However, there are also studies that concur with theresults of the present study.4,10,13 In an in vitro study of phosphate-methacrylate monomer luting agents, Tjanand Nemetz13 demonstrated that substantial voids were present with an adhesive resin luting agent and sug-gested that these voids were responsible for the unex-pectedly low retentive values for dowels luted withresin luting agents. Additionally, Bouillaguet et al10

investigated microtensile bond strength betweenadhesive luting agents and root canal dentin. These au-thors indicated that bonding for some materials, such asdual-polymerized Panavia F, tends to fail in the intact

root canal. The polymerization shrinkage stress in the

confinement of the intact root canal is reported to ex-ceed the bond strength, causing the bond of the lutingagent in the root canals to fail.10,12 Adhesive resin lutingagents are also technique-sensitive, and there have beenreported difficulties in manipulating resin luting agentsin vitro.4,7,8,10,13,14 In a study of the retention of dowels

under tensile forces, Mendoza and Eakle

8

observed nosignificant difference between a non–resin-containingluting agent and an adhesive resin luting agent(Panavia) but mentioned difficulties in manipulatingthe resin luting agent. Because of premature polymeri-zation of the resin, some dowels did not seat in theroot canals. Although a premature polymerization wasnot observed in the present study, this should be consid-ered as a factor in evaluating bond strengths.

Some studies of microleakage indicate that zinc-phosphate cement caused more microleakage of dowelsand cores and other restorations than resin lutingagents.17,18 These authors report that this was due tothe greater solubility of zinc-phosphate cement.16,18

Although in the present study, higher retention values were observed with zinc-phosphate cement, dissolutionof this type of cement should also be considered, as itmay negatively affect retention over time.

Studies have shown that the bond between resin-based luting agents and metal alloys is made consider-ably stronger with the use of a surface modificationprocedure of metal alloys, such as silane coat-ing.22,25,26,28-31 Silica coating not only promotes adhe-sion but also reduces gap formation at the resin andmetal interface.28,30 The silane coating procedure re-

sulted in higher bond strengths with base metal alloysthan noble alloys in some studies, and using this proce-dure was suggested for the treatment of base metal alloysto improve bond strengths with adhesive lutingagents.22,26,29 However, there are also some studiesthat observed decreased bond strength of base metalalloys with silane coating.12,23 Bahannan andLacefield12 concluded that the bond strengths betweenphosphate-methacrylate resin luting agents and basemetal alloys were significantly more effective comparedto the bond strengths of silane coating. Furthermore,the phosphate-methacrylate resinluting agents alone ap-

peared to be easier to use. In another investigation con-ducted by O’Keefe et al,11 the silica coating treatment of Ni-Cr cast dowels and cores apparently interfered some- what with the tensile bond strength of phosphate-meth-acrylate resin luting agents. Both of these conclusionssupport the findings of the present study, as Panavia Fshowed slightly higher tensile bond strength valuesthan Panavia F with the Siloc surface-conditioning tech-nique. This may be the result of the Siloc surface-condi-tioning technique covering the oxide layer anddecreasing the bond strength of functional monomers,such as Panavia F, which have a high affinity for metal

oxides such as chromium, tin, and copper.23,24,34





Although clinical recommendations can be made,there are certain limitations to the present study thatmust be considered. Complicating variables were elimi-nated to help simplify the analysis of data. Variables suchas temperature changes, which are common in an oralenvironment, may also affect the properties of luting

agents. Additionally, the occlusal forces are muchmore complex than forces applied using a simple tensiletest. Shearing, rotational, and cyclical forces are alsoplaced on teeth and restorations. Future research shouldconsist of in vitro tests that more accurately replicate theclinical condition.

CONCLUSION

This in vitro study used tensile testing to allow fordowel retention comparisons of a conventional zinc-phosphate, a phosphate-methacrylate resin, and a phos-phate-methacrylate resin luting agent with the metal

dowel surfaces modified by a silane coating. Within thelimitations of this study, the tensile strength of zinc-phosphate cement was significantly higher than that of the phosphate-methacrylate resin luting agent whenused with and without the silane coating treatment of cast metal dowel surfaces. There was no significant dif-ference observed between the tensile bond strengthsof the phosphate-methacrylate resin luting agent whenused with and without the silane coating treatment.The cast metal dowels without silane coating surfacetreatment showed slightly higher mean retentive values.

The authors thank Dr Bulent Dayangac and Dr Ibrahim

Tulunoglu, Hacettepe University, Ankara, Turkey, for their help in

the experimental phase of this study.

REFERENCES

1. Miller BH, Nakajima H, Powers JM, Nunn ME. Bond strength betweencements and metals used for endodontic posts. Dent Mater 1998;14:312-20.

2. Chan FW, Harcourt JK, Brockhurst PJ. The effect of post adaptation in the

root canal on retention of posts cemented with various cements. AustDent J 1993;38:39-45.

3. Ross RS, Nicholls JI, Harrington GW. A comparison of strains generatedduring placement of five endodontic posts. J Endod 1991;17:450-6.

4. Morgano SM, Brackett SE. Foundation restorations in fixed prosthodon-tics: current knowledge and future needs. J Prosthet Dent 1999;82:

643-57.5. Bergman B, Lundquist P, Sjogren U, Sundquist G. Restorative and

endodontic results after treatment with cast posts and cores. J ProsthetDent 1989;61:10-5.

6. Gutmann JL. The dentin-root complex: anatomic and biologicconsiderations in restoring endodontically treated teeth. J ProsthetDent 1992;67:458-67.

7. Rosin M, Splieth C, Wilkens M, Meyer G. Effect of cement type onretention of a tapered post with a self-cutting double thread. J Dent

2000;28:577-82.8. Mendoza DB, Eakle WS. Retention of posts cemented with various

dentinal bonding cements. J Prosthet Dent 1994;72:591-4.9. Standlee JP, Caputo AA. Endodontic dowel retention with resinous

cements. J Prosthet Dent 1992;68:913-7.10. Bouillaguet S, Troesch S, Wataha JC, Krejci I, Meyer JM, Pashley

DH. Microtensile bond strength between adhesive cements androot canal dentin. Dent Mater 2003;19:199-205.

11. O’Keefe KL, Powers JM, McGuckin RS, Pierpont HP. In vitro bond strength

of silica-coated metal posts in root of teeth. Int J Prosthodont 1992;5:373-6.

12. Bahannan S, Lacefield WR. An evaluation of three methods of bondingresin composite to stainless steel. Int J Prosthodont 1993;6:502-5.

13. Tjan AH, Nemetz H. Effect of eugenol-containing endodontic sealeron retention of prefabricated posts luted with adhesive composite resin

cement. Quintessence Int 1992;23:839-44.14. Duncan JP, Pameijer CH. Retention of parallel-sided titanium posts

cemented with six luting agents: an in vitro study. J Prosthet Dent 1998;80:423-8.

15. Nergiz I, Schmage P, Platzer U, McMullan-Vogel CG. Effect of differentsurface textures on retentive strength of tapered posts. J Prosthet Dent1997;78:451-7.

16. Mannocci F, Ferrari M, Watson TF. Microleakage of endodonticallytreated teeth restored with fiber posts and composite cores aftercyclic loading: a confocal microscopic study. J Prosthet Dent 2001;

85:284-91.17. Bachicha WS, DiFiore PM, Miller DA, Lautenschlager EP, Pashley DH.

Microleakage of endodontically treated teeth restored with posts. J Endod1998;24:703-8.

18. Rosenstiel SF, Land MF, Crispin BJ. Dental luting agents: a review of thecurrent literature. J Prosthet Dent 1998;80:280-301.

19. Parsa RZ, Goldstein GR, Barrack GM, LeGeros RZ. An in vitro comparisonof tensile bond strengths of noble and base metal alloys to enamel.

J Prosthet Dent 2003;90:175-83.20. Mitchell CA, Abbariki M, Orr JF. The influence of luting cement on the

probabilities of survival and modes of failure of cast full-coverage crowns.Dent Mater 2000;16:198-206.

21. Burgess JO, Summitt JB, Robbins JW. The resistance to tensile, compres-sion, and torsional forces provided by four post systems. J Prosthet Dent1992;68:899-903.

22. Hansson O, Moberg LE. Evaluation of three silicoating methods for resin-

bonded prostheses. Scand J Dent Res 1993;101:243-51.23. Tulunoglu IF, Oktemer M. Tensile strength and microleakage of t he bond

between a nickel-chromium alloy and a visible light-cured resin compos-ite: effect of 4-META, silicoating, and bead retention. Quintessence Int1997;28:447-51.

24. Yoshida K, Kamada K, Tanagawa M, Atsuta M. Shear bond strengths of

three resin cements used with three adhesive primers for metal. J ProsthetDent 1996;75:254-61.

25. Antoniadou M, Kern M, Strub JR. Effect of a new metal primer on the bondstrength between a resin cement and two high-noble alloys. J ProsthetDent 2000;84:554-60.

26. Moulin P, Degrange M, Picard B. Influence of surface treatment on adher-ence energy of alloys used in bonded prosthetics. J Oral Rehabil 1999;26:413-21.

27. Mudford L, Curtis RV, Walter JD. An investigation of debonding betweenheat-cured PMMA and titanium alloy (Ti-6Al-4V). J Dent 1997;25:

415-21.28. Kolodney H Jr, Puckett AD, Breazeale MS, Patterson KL, Lentz DL. Shear

bond strengths of prosthodontic adhesive systems to a nickel-chromium-beryllium alloy. Quintessence Int 1992;23:65-9.

29. Naegeli DG, Duke ES, Schwartz R, Norling BK. Adhesive bonding of composites to a casting alloy. J Prosthet Dent 1988;60:279-83.

30. Kourtis SG. Bond strengths of resin-to-metal bonding systems. J ProsthetDent 1997;78:136-45.

31. Barzilay I, Myers ML, Cooper LB, Graser GN. Mechanical and chemicalretention of laboratory cured composite to metal surfaces. J Prosthet

Dent 1988;59:131-7.32. Ishijima T, Caputo AA, Mito R. Adhesion of resin to casting alloys. J Pros-

thet Dent 1992;67:445-9.33. Sen D, Nayir E, Pamuk S. Comparison of the tensile bond strength of

high-noble, noble, and base metal alloys bonded to enamel. J ProsthetDent 2000;84:561-6.

34. Behr M, Rosentritt M, Groger G, Handel G. Adhesive bond of veneeringcomposites on various metal surfaces using silicoating, titanium-coatingor functional monomers. J Dent 2003;31:33-42.

35. Matsumura H, Yanagida H, Tanoue N, Atsuta M, Shimoe S. Shear bondstrength of resin composite veneering material to gold alloy with varyingmetal surface preparations. J Prosthet Dent 2001;86:315-9.

36. Watanabe I, Kurtz KS, Kabcenell JL, Okabe T. Effect of sandblasting and

silicoating on bond strength of polymer-glass composite to cast titanium. J Prosthet Dent 1999;82:462-7.


MAY 2005 451



37. Ohkubo C, Watanabe I, Hosoi T, Okabe T. Shear bond strengths of poly-

methyl methacrylate to cast titanium and cobalt-chromium frameworksusing five metal primers. J Prosthet Dent 2000;83:50-7.

38. Andrade Tarozzo LS, Chiarello De Mattos MDA, Ribeiro Faria R, SempriniM. Comparison of retentive systems for composites used as alternatives toporcelain in fixed partial dentures. J Prosthet Dent 2003;89:572-8.

39. Almilhatti HJ, Giampaolo ET, Vergani CE, Machado AL, Pavarina AC.

Shear bond strength of aesthetic materials bonded to Ni-Cr alloy. J Dent2003;31:205-11.

40. Akisli I, Ozcan M, Nergiz I. Resistance of core materials against torsionalforces on differently conditioned titanium posts. J Prosthet Dent 2002;88:367-74.

41. Akisli I, Ozcan M, Nergiz I. Effect of surface conditioning techniqueson the resistance of resin composite core materials on titanium posts.Quintessence Int 2003;34:766-71.

Reprint requests to:

DR H. ZEYNEP ERTUGRUL

SCHOOL OF DENTAL MEDICINE

UNIVERSITY OF PITTSBURGH

3501 TERRACE STREET

PITTSBURGH, PA 15261

FAX: 412-648 8850E-MAIL: [email protected]

0022-3913/$30.00Copyright Ó 2005 by The Editorial Council of The Journal of Prosthetic

Dentistry .

doi:10.1016/j.prosdent.2005.03.001

A 10-year randomized clinical trial on the influence of splinted and

unsplinted oral implants retaining mandibular overdentures:Peri-implant outcomeNaert I, Alsaadi G, van Steenberghe D, Quirynen M. Int J Oral Maxillofac Implants 2004;19:695-702.

Purpose: This randomized controlled clinical trial aimed to evaluate the efficacy of splinted implants versusunsplinted implants in overdenture therapy over a 10-year period.Materials and Methods: The study sample comprised 36 completely edentulous patients, 17 men and 19 women (mean age 63.7 years). In each patient, 2 implants (Branemark System, Nobel Biocare, Goteborg,Sweden) were placed in the interforaminal area. Three to 5 months after placement, they were connected tostandard abutments. The patients were then rehabilitated with ball-retained overdentures, magnet-retained

overdentures, or bar-retained overdentures (the control group). Patients were followed for 4, 12, 60, and 120months post–abutment connection. Group means as well as linear regression models were fitted withattachment type and time as classification variables and corrected for simultaneous testing (Tukey).Results: After 10 years, 9 patients had died and 1 was severely ill. Over 10 years, no implants failed. Mean PlaqueIndex, Bleeding Index, change in attachment level, Periotest values, and marginal bone level at the end of thefollow-up period were not significantly different among the groups.Discussion: The annual marginal bone loss, excluding the first months of remodeling, was comparable withthat found around healthy natural teeth.Conclusion: The fact that no implants failed and that overall marginal bone loss after the first year of boneremodeling was limited suggested that implants in a 2-implant mandibular overdenture concept have anexcellent prognosis in this patient population, irrespective of the attachment system used.—Reprinted with

permission of Quintessence Publishing.

Noteworthy Abstractsof theCurrent Literature



mailto:[email protected]







ertugrul et al 34568

Documents