JOURNAL OF ESTHETIC DENTISTRY VOLUME 4, SUPPLEMENT 1992

Quantitative Analysis of Six Composite Polishing Techniques on a Hybrid Composite Material William H . Tate, D.D.S.," Edward J . DeSchepper, D.D.S.,M.A., Ed.jand Teresa Cody, D.D.S.

Determining the best technique for finlshing and polishing composite resins is important to ensure longevity of the restoration and prevention of recurrent decay and periodontal disease. This study quantitatively compared the surface roughness of a small particle hybrid compositematerial finished and polished using six dif€erent techniques. Five composite samples were randomly assigned to one of six polishing techniques. Uniform composite surfaces were prepared by Anishing samples with a 600-grit carborundum disk prior to polishing. The unpolished surfaces were analyzedwith theTaylor-HobsonTalysurf 10surface texture measuring instrument. The surfaces were then polished and analyzed again. There were no statistical differences among treatment groups prior to polishing. There was a statistical difference between treatment groups after polishing. The smoothest surfaces were obtained using Centrix System rubber points alone, Centrix System rubber points plus Caulk's Prisma Gloss h e and super-fine pastes, and Caulk's Enhance disks plus Caulk's Prisma Gloss fine and super-he pastes. There was no statistical Merence between these methods and 3M Sof-flex disks alone. The roughest surface was produced by the Enhance disks only without using the Prisma Gloss pastes. There was no statistical differencebetween this method, however, and the use of Sofflex disks plus Kerr's Lustre Paste. Lustre Paste, includedwith Herculite kits, did not improve a surface polished with Sof-flex disks.

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laque retention is hindered by the increased smoothness of a surface. Determining the best technique for finishmg and polishing restorations, therefore, is important in the prevention of recurrent decay and periodontal disease. Since the introduction of dental composite resin, polishing techniques for this material have been studied extensively.'"As new composites and new polishing techniques have been developed,amyriad of studies have followed. Several new polishing materials and techniques have recently been developed. It was the purpose of this study to compare quantitatively the surface roughness of a small particle hybrid composite material finished and polished using six different polishing techniques.

wells of the same dimensions with a curing light (CoeUte, Coe Laboratories, Chicago, IL) for 80 seconds. After curing, the samples were surfaced with a 600-grit carborundum disk on a Buehler Polimet I Polisher (Buehler Ltd, Lake Bluff, IL) to produce a uniform pretreatment surface. The samples were then randomly assigned to one of six polishing treatments until each treatment group contained five samples. The treatment groups are listed in Table 1, and the polishing products and their respective manufacturers are listed inTable 2. The ground surfaces were analyzed using a surface texture-measuring instrument (Taylor-HobsonTalysurf 10, Rank Taylor Hobson Limited, Leicester, England) prior to polishing. Five measurements were taken at different locations on each of the samples and recorded. The samples were then polished according to each of the treatment groups. All materials were used according to the manufacturer's recommendations, except in Treatment 1 in which the Enhance Prisma Gloss paste was used after the CenMx System. Surface roughness of the treated surfaces was evaluated again using the surface texture measuring instrument. Pretreatment and posttreatment data were analyzed separately using a nested ANOVA (MMtab, Version 8.0, Minitab Inc., State College, PA3 and Tukey's Multiple Comparison Test9 at the 95%confidence level. In previous studies. the mean of several measurements made on the same sample has

MATERIALSAND METHODS Thirty cylindricalsamples 3 mm in height and 7 mm in diameterof a smallparticlehybrid composite(Herculite XR, Sybron/Kerr, Romulus, MI) were cured in plexiglass *AssistantProfessor. UniversityofT-Dental Branch, Houston. Taras; tAssociate Professor. Indiana University School of Dentistry. Operative Dentistry Department, Indianapolis. Indiana 'Address reprlnt requests to Dr. William Tate. Universityof Texas-Dental Branch. 6516 John Freeman Avenue. Houston. TX 77030-3402 61 1992 Decker periodicals Inc.

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Composite Polishing Techniques

been calculated, and statistical analysis has been performed on these average^.^.^,^.^ This method does not account for variability among readings on the same sample (within sample variability). The nested ANOVA statistical method does account for this variability and is thus a more powerful statistical test of this type of data.g This is the rationale for using this statistical method.

Table 1.

Mean Surface Roughness Average

Polishing Treatment

Pretreatment pn (SDI

1. Centrix cups plus Enhance Prisma Gloss pastes 2. Centrix cups only 3. Enhance disks plus Enhance Prisma Gloss pastes 4. Enhance disks only 5. Sof-flex disks plus Lustre paste 6. Sof-flex disks only

RESULTS

Posttreatment pm (SO)

0.11 (0.03)

0.027 (0.009)

0.1 10 (0.027) 0.120 (0.029)

0.086 (0.025) 0.027 (0.008)

0.14 (0.06) 0.103 (0.028) 0.12 (0.04)

0.19 (0.08) 0.16 (0.06) 0.094 (0.023)

Means and standard deviations of surface roughness of the six treatment groups are listed inTable 1.The coefficients of variation for pretreatment and posttreatment data were 9.1% and 29.3?40, respectively. There was no statistically significant difference in surface roughness among treatment groups prior to polishing. Analysis of surface roughness after polishing resulted in statistically significantdifferences among treatment groups. The Tukey Interval among treatment groups was 0.75. Differences between surface roughness means greater than the Tukey Interval were considered significant (p 2 .05). Among treatment groups, treatments 1,2,and 3produced the smoothest surfaces. There was no statistically significant difference in surface roughness among groups 1 , 2 , 3 , and 6 or between groups 5 and 6. Group 4 produced the roughest surface. However, there was no statistically sigmficant difference between groups 5 and 4.

Interestingly, Lustre Paste, which was provided with the Herculite X R kits, did not improve a surface that had been previously prepared with Sof-flexdisks. A previous study’had also found no improvement in surface roughness when using this paste after Sof-flex disks. Based upon these data, the use of Lustre Paste after Sof-flex disk application is unnecessary. The Centrix system recommends the use of their abrasive cups in awet environment. This may be significant since a previous study suggested that the dry use of abrasive disks may lead to excessive microleakage in composite restorations. lo Centrix cups plus Enhance Prisma Gloss pastes produced one of the smoothest surfaces as measured with the surface texture measuring instrument.

DISCUSSION

CONCLUSIONS

Surface analysis of the samples and statistical analysis of the data confirmed that there was no difference among the treatment groups prior to treatment. Any differences among groups observed after treatment were attributed to the effects of different polishing treatments. Treatments utilizing either aluminum oxide or aluminum silicate-impregnated disks, cups, and pastes (groups 1 , 2 , 3 ,and 4) seemed to produce the smoothest surfaces. There was no statistical difference in surface roughness between Sof-flex disks alone and the use of Prisma Gloss pastes as measured by the surface texture analyzer. Moreover, a previous study had also found no statistical difference between the two methods.2These data may reflect the inability of the measuring instrument to make flne distinctions in surface Anishes. Perhaps surface reflectance values used in another study” may indicate a more sensitive measuring technique. Of all the techniques utilized, the Enhance disks used alone produced the roughest surface. The manufacturer recommends that different surface textures can be produced by varying the pressure applied to the abrasive. The moderate polishing pressure applied in this study produced a rough surface. However, Enhance disks followed by Prisma Gloss pastes produced one of the smoothest surfaces. These results indicate that a significantly smoother surface is produced with the use of F’risma Gloss pastes after Enhance disk application.

Polishing treatments of Centrix cups plus Enhance Prisma Gloss pastes (1). Centrix cups only (2),and Enhance disks plus Prisma gloss paste (3)produced the smoothest surface on Hercdite X R Composite. Of all the polishing methods tested, treatment with Enhance disks only (4) produced the roughest surface on Herculite XR. This treatment should be followed by the application of Prisma Gloss pastes to produce a smoother surface. There was no statistically significant difference in surface roughness among treatments of Centrix cups plus Prisma Gloss paste (l),Centrix cups only (2). Enhance disks plus Prisma Gloss pastes (3), and Sof-flex disks only (4).As well, there was no statistical difference between Sof-flexdisks plus Lustre Paste (5)and Sof-flex disks only (6). Based on the results of this study, application of Lustre Paste after use of Sof-flex disks does not improve the surface roughness on Herculite XR composite.

‘Tukey Interval = 0.075

Table 2. Polishing Products and Respective Manufacturers Materlal Centrix polishing cups Enhance polishing disks Prisma Gloss polishing pastes Sof-flex disks Lustre paste

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Manufacturer

Locatlon

Centrix Inc. Caulk/Dentsply Caulk/Dentsply 3M Sybron/Kerr

Milford, CT Milford, DE Milford, DE St. Paul, MN Romulus, MI

JOURNAL OF ESTHETIC DENTISTRY VOLUME 4. SUPPLEMENT 1992

6. Chen RCS, Chan DCN, Chan KC. A quantitative study of finishing and polishing techniques for a composite. J Prosthet Dent 1988; 59:292-297. 7. Boghosian AA. Randolph RG. J e w s VJ. Rotary instrument finishing of microfilled and small-particle hybrid composite resins. J Am Dent Assoc 1987; 115:299-301. 8. Goldstein GR.Waknine S.Surface roughness evaluation of composite resin polishing techniques. Quintessence Int 1989; 20:199-204. 9. Zar JH. Biostatistical analysis. 2nd Ed. Englewood Cliffs, NJ:Prentice-Hall, 1984. 10. Xin YI Yu MM, Wieczkowski G, Davis EL, Joynt FU3. The influence of finishing technique on microleakage.J Esthet Dent 1990; 2: 142-144.

REFERENCES 1. Stoddard J W , Johnson GH. An evaluation of polishing agents for composite resins. J Prosthet Dent 1991; 65: 491-495. 2. Herrgott A-ML. Ziemiecki TL, Dennison JB. An evaluation of different composite resin systems finished with various abrasives. J Am Dent Assoc 1989; 119:72!3-732. 3. Northeast SE. van Noort R. Surface characteristics of finished composite resins. Dent Mater 1988; 4:278-288. AHL, Chan CA. The polishabilityof posterior compos4. T~an ites. J Prosthet Dent 1989: 61:138-146. 5. Eide R 'Met AB. Finishing and polishing of composites. Acta Odontol Scand 1988; 46:307-312.

Marginal Leakage of a New Adhesive Restorative System: A Preliminary In Vivo Investigation Marco Ferrari, D.D.S.," Werner J . Finger, D.D.S., Ph.D.1 and Andrea Gesi, D.D.S.

The efficacy of newly developed adhesive restorative materials is commonly described by in uitro test results such as bond strength and microleakage data. Due to the inconsistency often found between in uitro testing and in uiuoperfomance, the purpose of the present investigationwas to restore teeth scheduled for extraction in uivowith an experimentalrestorative bonding system and to evaluate the microleakage of the restorations by common laboratory techniques following extraction after 3 months of clinical service. Two restorations were placed in each of seven anterior teeth, one in the middle of the labial enamel portion and the other labially extending over the cementoenameljunction (CEJ). Six of the seven fillings completely surrounded by enamel showed no microleakage. However, two of the restorations crossing the C W revealed microleakage originating from the cervical margins. In spite of the small number of flllinEls assessed, the experimental enamel-dentin adhesive compound tested is preliminarily considered a promising new system.

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he function of adhesive restorative materials is to achieve a firm and consistent adaptation between cavity wall and restoration. Insufacientbondingstrength may result in total or partial debonding of the filling. Such debonding is primarily caused by the polymeriza-

tion contraction of restorative resins, and by repetitive thermal and/or mechanical stresses acting on the bonding i n t e r f a ~ e . ~ Consecutively, .~ marginal opening and the presence of gaps may lead to bacterial or toxin invasion along the cavity wall. The possible consequences are formation of caries, adverse pulp reactions, and marginal staining of the r e s t o r a t i ~ n .Recently, ~.~ an experimentaldentoenamel bonding agentwas presented by Kubo et al.s This compound was reported to micromechanically bond composite restorative resins to conditioned enamel and dentin. According to the authors, a resin-impregnated mne in inter- and peritubular dentin is readily achieved due to the compounds outstanding wetting of and penetration into acid-conditioned dentin.

'Assistant Professor. Siena University.School of Dentistry. Departmentof ConservativeDentistry. Siena. Italy: t Professor. Universityofhchen. Dental School. Departmentof ProstheticDentism and Dental Materials and Department of Clinical Research and Dental Materials Sclence. Bayex Dental. Dormagen. Germany; *Instructor. Siena University. School of Dentistry, Siena. Italy Address reprint requests to Dr. Manx, Fermi. Piazza Attla 19, 57125 Livorno. Italy 0 1992 Decker PeriodicalsInc.

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Quantitative analysis of six composite polishing techniques on a hybrid composite material.

Determining the best technique for finishing and polishing composite resins is important to ensure longevity of the restoration and prevention of recu...
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