Restorative Dentistry

Evaluation of the handling of a new compomer and noveldispensing system in general dental practiceR. J. Crisp, BDS*/F. J. T. Burke, MDS, MSc, DDS, FDS, MGDS*

Objective: Easy handling of materials is essential lo the production of good clinical results. The handlingproperties ofa new compomer material and ils novel piimer/adhesive-dispensing .system were tesied inclinical use.Method and materiais: Ten general dental practitioners used the new material and dispenser for 3 weeksand completed a questionnaire regarding the handling, esthetics, and ease of use. They were asked to com-pare the new material to the compomer; resin composite, and glass-ionomer materials normally used intheir own practice.Results: The material scored a mean of 4.4 for dispensing convenience on a linear scale of 1 (inconve-nient) to 5 ¡convenient) and 4.6 for ease of use (5 = easy to use, and 1 = difficult to use). The dispensingsystem achieved a high rating of 4.9 for convenience (5 = convenient, and J = inconvenient).Conciusion: The new material received ratings thai ivere superior to those of ihe glass-ionomer and com-pomer materials normally used by ihe evalualors and similar to ratings of ¡he resin composite normallyused. (Quintessence Int 1998:29:775-779)

Key words; clinical evaluation, compomer. pnmer/adhesive-dispensing f,ystem

Clinical relevance

The new compomer and novel primer/adhesive-dispen.sing system tested achieved high ratings forease of use and convenience in clinical practice.

Easy handling and dispensing of dental materials iscentral to the achievement of effective clinical prac-

tice. Indeed, it may be considered that materials and de-vices that are easily used may allow the general dentalpractitioner to produce more optimum results than ma-terials that are not user-friendly. It is therefore essentialthat new materials and devices he straightforward tohandle and use.

The aim of this study was to assess the handling of arecently developed •"compomer" material and its associ-ated primer/adhesive-4ispensing sy.stem in general den-tal practice.

*Denial Primary Care. University of Glasgow, Dental Hospital, Glasgow.Scotland.

ReprinI requests: Dr F. J. T. Burke. Denial Primari' Care. Universily ofGlasgow, Denial Hospital, 378 Sauchiehall Sireel. Glasgow G2 3JZ,Scotland. E-mail: f.j.l.burked'dental.glíL.ac.uk

A group of UK-based dental practitioners prepared tocomplete évaluations of new materials and techniques inthe practice environment was established in 1993.' Thisgroup, the Product Research and Evaluation by Prac-titioners IPREPI Panel, presently comprises 23 mem-bers with an average time since graduation of 16 years.Four of the panel members are female.

Method and materials

A questionnaire was designed to elicit some backgroundinfortnation on the evaluators' clinical practice and ontheir opinion of the ease of u.se and handlingcharacteristics of the material being assessed, princi-pally using linear visual analog scales to determine thisinformation.

An information sheet and consent form for partici-pating patients was designed and submitted for EtbicalCommittee approval along with the protocol for theevaluation: Ethical Committee approval was granted.

Ten general dental practitioners among the membersof the PREP Panel were selected at random to carry outthe evaluation. The experimental compomer (now avail-able as F2000. 3M Dental) (Table I) and its primer/ad-hesive-dispensing system (now available as Clicker. 3MDental] (Table 2 and Fig 1) were distributed to eachevaltiator on 10 May 1997. Each evaluator was re-quested to use the material for 3 weeks, or for a tnaxi-

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Crisp/Burke

TABLE 1 Composition of F2000 paste

Comoonent

FAS GlassCarboxyiate dimethacrylate

(CDMA)Glyceryl dimethacrylate

(GDMA)Poiy(vinyi pyrrolidone)

(PVNP)Camphorquinone (CPO)

Function

Long-term liuoride release

Acidic hydrophiiic matrix former

Hydrophilic compomerTransports water and

liuoride: rheoicgy modifierPhoto initiator

TABLE 2 F2000 primer/adhesive dispenser (Glicker)

Side A

Vitrebond copolymerHydroxyethyl methacryiateWaterEthanolPhofoinitiators

WaterMaieic acid

Resullanl minture = Vilremer primer + 2.5% maieic acid.

Fig 1 The Clicker pnmer/adhesive-dispensing system.

mum of 25 restorations (with a maximum of two restor-ations per patient), and to complete and return the ques-tionnaire as soon as possible after completion of theevaluation.

The first part of the questionnaire, to be completedbefore use of F2000. asked the evaluators to rate theease of use of the resin composite and glass-ionomercement materials that they normally used in their prac-tice. The second and third parts of the questionnaireasked the evaluators to assess the handling, esthetics,and ease of use of the new material and to compareF2000 to the other materials they used. The data col-lected in the questionnaire were collated and analyzed.

Results

Of the ten evaluators selected, eight were male, andtheir mean time since graduation was 17 years (range of4 to 33 years).

All evaluators returned the questionnaire. The resultsindicated that they used a wide variety of resin compos-ite and glass-ionomer materials prior to the study. Theprincipal reasons stated for using these materials weregood esthetics, ease of use, and polishability for com-posite, and ease of use, esthetics, and good clinical per-formance for glass-ionomer cement.

Eight of the evaluators had previously used a com-pomer material. These evaluators rated their prestudycompomer as relatively easy to use (Fig 2). When askedto rate the ease of use of the composite and glass-

ionomer materials used prior to the study, the evaluatorsindicated that their composite was very easy to ase butthat their glass-ionomer was less so (Figs 3 and 4).

Six of the evaluators stated that F2000 handled as ex-pected (for a compomer). Two stated that it was easierto handle than anticipated. One evaluator commentedthat it handled like a composite, and one indicated thatit was not sufficiently viscous.

The total number of restorations placed was 236, in-cluding 125 Class V, 87 Class III, and 24 other restora-tions. The evaluators indicated that all the Class IIIrestorations were placed using a matrix but that a major-ity of Class V restorations were placed freehand.

The dispensing of F2000 was regarded as convenient(Fig 5). Six of the evaluators reported no difficulty withthe material sticking to instruments. The remainderreported slight sticking, which was overcome by usinglight pressure and the use of small increments of mate-rial. The evaluators were asked to state if the materialflowed satisfactorily when pressure was applied by amatrix or instrument; the result is indicated in Fig 6.The rating of the viscosity of the material is illustratedin Fig 7.

Eight of ihe evaluators considered that the restora-tions were easy to finish and polish using the Sof-Lexdisks (3M Dental) provided for the evaluation, althoughone evaluator .stated that it was easy to overtrim the ma-terial if a diamond bur were used at high speed. Oneevaluator reported crazing at the margins after polish-ing. Seven of the evaluators stated that the material pol-ished to a high gloss. Of the remaining three, one staledthat the clinical result in terms of surface finish wassimilar to that of a hybrid composite but not as good asthat of a microfilled composite.

The overall esthetic quality of the F2000 restorationswas rated as indicated in Fig 8. Eight of the evaluatorsstated that Ihe restoration margins were generally visu-ally satisfactory.

When asked to report any (iifficulfies experiencedduring the placement and finishing of the F2000 restor-ations, one evaluator reported that it was necessary for

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Easy to use Difficult to use Easy lo use

CrJsp/Burke

Difficult to use

Fig 2 Ease of use of the compotner materials used prior to the Fig 3 Ease of use of the resin composite materials used prior tostudy. the study.

Easy to use Diffîcult to use

3.9

Convenient

4.4

Fig 4 Ease of use of the glass-ionomer materials used prior to Fig 5 Dispensing o( F200D.the study.

Satisfactory Unsatisfactory

4.5

Fig 6 Row of F2000 under pressure from a matrix.

Too VISCOUS

12.9

Too thin

1

Fig 7 Viscosity of the maleriai.

Too translucent

3.5

Too opaque

1

Fig 6 Overall esthetic quality of the F2000 restorations Fig 9 Translucency or opacity of tlie material.

Easy to use Difficult to use

4.6

Fig 10 Overall ease of use of F2000 material.Fig 11 Ease of use of the F2000 primer/adhesive-dispensingsystem (Clicker).

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TABLE 3 Evaluators' (n = 10) ratings of F2000 com-pomer compared to the resin composite material nor-mally used

Rating Handling

TABLE 4 Evaluators'(n = 10} ratings of F2000com-pomer cotnpared to the glass-ionomer material nor-mally used

Rating Handling Estiietics Marginal quality

the primer/adhesive liquid to be fully evaporated for therestorative material to adhere to the tooth surface.

The rating for the transi ucency/opacity of the tnate-rial is illustrated in Fig 9, while the overall ease of useof F20fl0 is illustrated in Fig 10.

Of the eight evaluators who had previously used acompomer material, four considered F2000 to be easierto use than the prestudy compomer material, and oneevaluator considered F2000 to be more difficult to use.Three rated the ease of use of F2000 to be the same asthat of their prestudy compotner material. Evaluatorswere asked to compare F2Ü00 with the re.sin compositeand glass-ionomer materials they normally used. The re-sults are shown in Tables 3 and 4, respectively.

The ease of use of the F2000 primer/adhesive-dispensing system (Clicker) is illustrated in Fig 11. Allevaluators stated that the dispensing system worked sat-isfactorily. Fvaluators made the following comments:(I) "Looked flimsy but had not broken." (2¡ "Dentalnurse really liked the dispenser—better than a bottle,and we could tell how much liquid was left." (3) "Savedsurgery time."

All evaluators stated that tbe protective top was eas-ily removed from the dispenser. All stated that theF2000 liquid was easy to apply to the tooth surface.Seven of the ten evaluators considered that the F2000liquid was easier to use than otber resins previouslyused. Of the retnainder, two stated that it was worse:one stated that it was less messy. Three evaluators statedthat they would have preferred the liquid to be more vis-cous. One stated that she was "disconcerted by the yel-low color" of the F2000 liquid but that this did not ap-pear to be a problem in clinical practice.

Seven of the ten evaluators stated that they wouldpurchase the material if it were available at averagecost.

Discussion

The members of the PREP Panel have been chosenprincipally from dentists attending continuing educationcourses held by tbe PREP Panel coordinator and whohave indicated a willingness to carry out practice-based

evaluations and clinical trials of new materials and tech-niques. It may be, therefore, that they are not truly rep-resentative of UK-based general dental practitioners.However, it may be considered to be impossible to ob-tain an absolutely "typical" group of general dentalpractitioners to carry out such projects, given that it mayonly be the more enthusiastic members of the profes-sion who would be prepared to become involved inpractice-based research. Nevertheless, it may be consid-ered that the handling of the material of this evaluationwas robustly tested by the evaluators. given that eachwas a practitioner subject to the pressures of a busypractice.

The constituents of the material under evaluation areshown in Tables I and 2. The fluoroalutnino-silicateglass used in the F2000 paste is the same as that used byits manufacturers in another product, Vitremcr (3MDental). It has an average particle size of about 3 (im, amaximum patticle size of 10 pm. and a filler loading of84% by weight.- The carboxylate dimethacrylateoligomer used in the paste is similar in composition tothe Vitrebond (3M Dental) copolymer, a methacrylatedpolycarboxylic acid.- The glyceryl dimethacrylate,which is chemically similar to hydroxyethyl methacry-late, acts as a diluent and copolymerizes with the car-boxylate dimethacrylate.

The constituents of the primer/adhesive are shown inTable 1. The two basic components, the maieic acid andthe resin system, are kept apart in tbe two barrels of thesystem until dispen.sed and mixed, thereby avoiding thepotential for acid-resin reactions to occur. Such reac-tions may occur, for example, when hydroxyethyl tneth-acrylate is mixed with maieic acid, resuhing in the for-mation of methacrylic acid. The mixture resulting fromthe contents of Clicker has a pH of 1-9 to 2.0-: thistherefore becomes a self-etching or in sito-etching sys-tem, which obviates the need for additional etching byphosphoric acid.

Although the evaluators were supplied with a proto-type version of the F200Ü kit, they were supplied withthe final version of the dispenser, now available asClicker, and high ratings of 4.9 were obtained for thisnovel system. The high rating achieved by the Clicker

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may be considered to indicate that, by providing simul-taneous dispensing of its two components, it overcomesmany of the difficulties that arise from messy adhesivebottles. Furt he nil ore, the Clicker system makes glove orskin contact with the resin primer/adhesive system diffi-cult and may therefore minimize the risk of sensitiza-tion in dental workers who handle the material.

Evaluators gave a rating of 3.5 (on a visual analogscale where 5 = too translucent and 1 = too opaque) forthe transi ucency/opacity of the F2000 material, indicat-ing that, in their opinion, the material was slightly tootranslucent. Viscosity was rated as ideal, at 2.9 (on a vi-sual analog scale where 5 = too viseous and 1 - toothin). The material also achieved high scores for han-dling; the score of 4.6 for ease of use [on a visual analogseale where 5 = easy and I - difficult to use) was supe-rior to the prestudy score for glass-ionomer (3.9) andsimilar to the prestudy score for resin composite (4.7).

Conclusion

A newly developed compomer material [F2000) liasheen subjected to an evaluation «f its handling in gen-eral dental practice, by 10 members of the PREP Panel,during which 236 restorations were placed. The restora-tive material received ratings that were superior to thoseof the prestudy glass-ionomer and compomer materialsand similar to those of the prestudy composite. Theprimer/adhesive-dispensing system (Clicker) was con-sidered very convenient.

Ackno wie dgmen ts

The authors acknowledge the fmancial support of 3M Dental, UnitedKingdom, for this study and thank the metnhers of the PREP Panelfor earning out the evaluation.

References

1. Burke EJT, Wilson NHF. Introducing the PREP Panel: DentPractl994;32|IS):30.

2. E2000 Compomer Restorative System Technical Product Profile,St Paul, MN: 3M, 1997.

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