Dent Mater 8:224-228, July, 1992
Three-year occlusal wear of posterior composite restorations M. A. Freilich 1, A.J. Goldberg1, R. O. Gilpatrick2, and R. J. Simonsen 2~ 1Departmentof Prosthodontics, Universityof Connecticut, School of Dental Medicine,Farmington, CT, USA 2Departmentof GeneralDentistry, Universityof Tennessee, Collegeof Dentistry, Memphis, TN, USA 3U.S. & International Dental ProductsDivision, 3M Health Care, St. Paul, MN, USA
Abstract. The specific aims of this study were to: 1) measure the occlusal wear of four different dental composite materials placed in the posterior teeth of adults; and 2) evaluate the effect of the clinical parameters, cavity class and tooth type on occlusal wear. Four differentvisible light-cured composite materials were usedto make the restorations in this study. The restorations placed for this randomized clinical trial were scored through the use of an indirect evaluation system (M-L scale). The total sample size per recall ranged from 90 to 142 restorations from baseline to 36 months, The mean wear at 36 months for Heliomolar, J&J Experimental (Adaptic II) and P-30 was 45- 54 pm, which is rather low compared to the recently reported wear of other composite materials, Marathon exhibited significantly greater wear with a mean of 174 pm at 36 months. The data also showed that cavity class and tooth type had no significant effect on the occlusal wear of the restorations made with the three low wear-rate materials, while restorations composed of the high wear-rate material exhibited more wear in molars than premolars; this effect was again not statistically significant. These data support the hypothesis that the overall wear of a composite restoration is more dependent on the material's properties than clinical parameters such as cavity class and tooth type.
Selection of subjects. As a subset ofalarger study, one hundred
INTRODUCTION Composite materials have been used to restore posterior teeth with varying degrees of success over the past two decades, Some of the earliest dental composite formulations proved unsatisfactory due to their poor resistance to occlusal wear (Phillips et al.,1973; Goldberg et al., 1984; Leinfelder et al., 1986a). Data from recent clinical trials have shown that the continued development of"posterior composites" has resulted in markedly improved resistance to wear (Boksman et al., 1986; Sturdevant et al., 1988; Lundin and Koch, 1989). While guidelines for the use of posterior composite materials have been proposed (Leinfelder and Lemons, 1988; Leinfelder, 1991), the effects of clinical parameters such as cavity class and tooth type on the wear resistance ofrestorations made with these materials remain unclear. In vivo studies with six- to sixty-month observations have found contrasting results when analyzing for these effects (Lutz et al., 1984; Boksman et al., 1986; Sturdevant et al., 1988; Rowe 1989; Bayne et al., 1991). It is possible that the effects of cavity class and tooth type on occlusal wear are largely dependent upon the particular composite material studied, and its overall
and forty six Class I and Class II restorations were placed in the posterior teeth of 47 healthy subjects (mean of 3.2 _+2.2 restorations per subject). The majority of the subjects who participated in this clinical trial were University of Connecticut Health Center employees and entering students. The age of this population ranged from 22 to 47 years (mean of 30 _+7.3 years). Potential subjects were screened by reviewing their dental and health histories and by performing clinical and radiographic examinations. Eligible subjects presented with a need for the restoration of posterior teeth as a result ofprimary or recurrent caries or defectiverestorations. Thoseindividuals who had a positive history of asthma, heart or liver disease, or those with signs or symptoms of TMJ disorders or malocclusions were excluded from the study. Furthermore, teeth selected for the study which upon preparation were not completely surrounded by enamel were excluded from the study. Study design. Four different visible light-cured composite materials were used to make the restorations in this study. They included three hybrid composites - "J&J Experimental" (commercially-available as Adaptic II - Johnson & Johnson, Skillman, NJ, USA; batch # 6459-82-1), "Marathon" (Den-Mat
224 Freilich et aL/Occlusal wear of composites
resistance to wear. The experimental composite materials used in the above studies, where the effects of these clinical parameters were analyzed, were found to exhibit greatly improved overall resistance to occlusal wear when compared to the earliest formulations. Materials which have been developed most recently, however, exhibit even greaterwear resistance. Since it is possible that the effects of these parameters are dependent on the overall wear characteristics of the material, it is logical to study the effects of cavity class and tooth type on these more wear-resistant, commercially-available matedals. The specific aims of this study were to: 1) measure the occlusa] wear of four different composite materials placed in the posterior teeth of adults; and 2) evaluate the effect of the clinical parameters, cavity class and tooth type on occlusal wear. In addition, pilot data were collected to study the effect of cavosurface margin configuration on the wear of these materials. MATERIALS AND METHODS
Inc., Santa Maria, CA, USA; batch # 256006 & 410283), and "P-30" (3M Dental Products Division, St. Paul, MN, USA; batch # 4RIP); and one microfil] composite, "Heliomolar Radiopaque" (Vivadent USA, Amherst, NY, USA; no batch # available at time ofplacement). The number and distribution of J&J Experimental and Marathon restorations were chosen to satisfythe guidelines ofADA acceptance in effect atthe time the study was begun (Council on Dental Materials, 1984). Accordingly, a minimum of two-thirds of the restorations was inserted into Class II cavity preparations, of which at least one-half involved molars. P-30 and Heliomolar Radiopaque were placed for comparison. The distributions of restorations by tooth and cavity type at placement for the four materials are shown in Table 1. The assignment of materials to study subject and tooth, and to clinical operator was made randomly. All restorations were placed by one of two experienced operators. For the restorations described in this paper, the cavity preparations were all of conventional design used for amalgam restorations and treatment was performed under optimal clinical conditions utilizing the rubber dam. The manufacturer's recommendations for each different material were followed throughout the various stages of tooth preparation, restoration placement, contouring, and finishing. With respect to cavity preparation, operator "one" utilized the butt joint configuration occlusal cavosurface finish line, while operator"two" placed an occlusal cavosurface bevel. Operator "one" placed 86 restorations while operator "two" placed 60 restorations. All exposed dentin was lined with a thin layer of calcium hydroxide (L. D. Caulk Div., Dentsply International Inc., Milford, DE, USA). Class II restorations were placed with the use ofa clear interproximal matrix (Contact Molar Bands, Vivadent USA) and anatomically formed wooden wedges, Each of the four composite materials was placed incrementally with a composite syringe (Centrix Inc. Stratford, CT, USA) after etching the enamel for 30 s with a gel etchant and placing a thin layer of the bonding agent supplied by the manufacturer. The composite placed in the proximal boxes of Class II preparations was polymer±zeal for the manufacturer's recommended time from the lingual, then from the buccal, and lastly from the occlusal direction. The occlusal surfaces of both Class I and Class II restorations and the buccal and lingual interproximal cavosurfaces were finished using 12fluted finishing burs and "Sof-lex" discs (3M Dental Products Division, St. Paul, MN, USA). Sof-Lexinterproximal finishing strips were also used to help establish interproximal contour. Collection of Data. The restorations were evaluated at baseline, 3, 6, 12, 24 and 36 months. This evaluation included the indirect assessment of occlusal wear through the use of stone replicas made from vinyl polysiloxane ("Express", 3M Dental Products Division) impressions of the experimental teeth. These replicas were independently scored by two examTABLE 1: SAMPLESIZEBYTOOTHAND CAVITYTYPEAT PLACEMENT
Material
Hetiomolar J&J Exp Marathon P-30 Total
Premolars Class l ClassII -1 2 -3
6 21 13 8 48
Molars Class l Classll 5 5 8 4 22
10 30 18 15 73
Total 21 57 41 27 146
TABLE 2: MEANOCCLUSALWEAR (pm) FORALL MATERIALS Recall Total Heliomolar J&J Exp Marathon P-30 Signif. (months) n p
Three-year occlusal wear of posterior composite restorations M. A. Freilich 1, A.J. Goldberg1, R. O. Gilpatrick2, and R. J. Simonsen 2~ 1Departmentof Prosthodontics, Universityof Connecticut, School of Dental Medicine,Farmington, CT, USA 2Departmentof GeneralDentistry, Universityof Tennessee, Collegeof Dentistry, Memphis, TN, USA 3U.S. & International Dental ProductsDivision, 3M Health Care, St. Paul, MN, USA
Abstract. The specific aims of this study were to: 1) measure the occlusal wear of four different dental composite materials placed in the posterior teeth of adults; and 2) evaluate the effect of the clinical parameters, cavity class and tooth type on occlusal wear. Four differentvisible light-cured composite materials were usedto make the restorations in this study. The restorations placed for this randomized clinical trial were scored through the use of an indirect evaluation system (M-L scale). The total sample size per recall ranged from 90 to 142 restorations from baseline to 36 months, The mean wear at 36 months for Heliomolar, J&J Experimental (Adaptic II) and P-30 was 45- 54 pm, which is rather low compared to the recently reported wear of other composite materials, Marathon exhibited significantly greater wear with a mean of 174 pm at 36 months. The data also showed that cavity class and tooth type had no significant effect on the occlusal wear of the restorations made with the three low wear-rate materials, while restorations composed of the high wear-rate material exhibited more wear in molars than premolars; this effect was again not statistically significant. These data support the hypothesis that the overall wear of a composite restoration is more dependent on the material's properties than clinical parameters such as cavity class and tooth type.
Selection of subjects. As a subset ofalarger study, one hundred
INTRODUCTION Composite materials have been used to restore posterior teeth with varying degrees of success over the past two decades, Some of the earliest dental composite formulations proved unsatisfactory due to their poor resistance to occlusal wear (Phillips et al.,1973; Goldberg et al., 1984; Leinfelder et al., 1986a). Data from recent clinical trials have shown that the continued development of"posterior composites" has resulted in markedly improved resistance to wear (Boksman et al., 1986; Sturdevant et al., 1988; Lundin and Koch, 1989). While guidelines for the use of posterior composite materials have been proposed (Leinfelder and Lemons, 1988; Leinfelder, 1991), the effects of clinical parameters such as cavity class and tooth type on the wear resistance ofrestorations made with these materials remain unclear. In vivo studies with six- to sixty-month observations have found contrasting results when analyzing for these effects (Lutz et al., 1984; Boksman et al., 1986; Sturdevant et al., 1988; Rowe 1989; Bayne et al., 1991). It is possible that the effects of cavity class and tooth type on occlusal wear are largely dependent upon the particular composite material studied, and its overall
and forty six Class I and Class II restorations were placed in the posterior teeth of 47 healthy subjects (mean of 3.2 _+2.2 restorations per subject). The majority of the subjects who participated in this clinical trial were University of Connecticut Health Center employees and entering students. The age of this population ranged from 22 to 47 years (mean of 30 _+7.3 years). Potential subjects were screened by reviewing their dental and health histories and by performing clinical and radiographic examinations. Eligible subjects presented with a need for the restoration of posterior teeth as a result ofprimary or recurrent caries or defectiverestorations. Thoseindividuals who had a positive history of asthma, heart or liver disease, or those with signs or symptoms of TMJ disorders or malocclusions were excluded from the study. Furthermore, teeth selected for the study which upon preparation were not completely surrounded by enamel were excluded from the study. Study design. Four different visible light-cured composite materials were used to make the restorations in this study. They included three hybrid composites - "J&J Experimental" (commercially-available as Adaptic II - Johnson & Johnson, Skillman, NJ, USA; batch # 6459-82-1), "Marathon" (Den-Mat
224 Freilich et aL/Occlusal wear of composites
resistance to wear. The experimental composite materials used in the above studies, where the effects of these clinical parameters were analyzed, were found to exhibit greatly improved overall resistance to occlusal wear when compared to the earliest formulations. Materials which have been developed most recently, however, exhibit even greaterwear resistance. Since it is possible that the effects of these parameters are dependent on the overall wear characteristics of the material, it is logical to study the effects of cavity class and tooth type on these more wear-resistant, commercially-available matedals. The specific aims of this study were to: 1) measure the occlusa] wear of four different composite materials placed in the posterior teeth of adults; and 2) evaluate the effect of the clinical parameters, cavity class and tooth type on occlusal wear. In addition, pilot data were collected to study the effect of cavosurface margin configuration on the wear of these materials. MATERIALS AND METHODS
Inc., Santa Maria, CA, USA; batch # 256006 & 410283), and "P-30" (3M Dental Products Division, St. Paul, MN, USA; batch # 4RIP); and one microfil] composite, "Heliomolar Radiopaque" (Vivadent USA, Amherst, NY, USA; no batch # available at time ofplacement). The number and distribution of J&J Experimental and Marathon restorations were chosen to satisfythe guidelines ofADA acceptance in effect atthe time the study was begun (Council on Dental Materials, 1984). Accordingly, a minimum of two-thirds of the restorations was inserted into Class II cavity preparations, of which at least one-half involved molars. P-30 and Heliomolar Radiopaque were placed for comparison. The distributions of restorations by tooth and cavity type at placement for the four materials are shown in Table 1. The assignment of materials to study subject and tooth, and to clinical operator was made randomly. All restorations were placed by one of two experienced operators. For the restorations described in this paper, the cavity preparations were all of conventional design used for amalgam restorations and treatment was performed under optimal clinical conditions utilizing the rubber dam. The manufacturer's recommendations for each different material were followed throughout the various stages of tooth preparation, restoration placement, contouring, and finishing. With respect to cavity preparation, operator "one" utilized the butt joint configuration occlusal cavosurface finish line, while operator"two" placed an occlusal cavosurface bevel. Operator "one" placed 86 restorations while operator "two" placed 60 restorations. All exposed dentin was lined with a thin layer of calcium hydroxide (L. D. Caulk Div., Dentsply International Inc., Milford, DE, USA). Class II restorations were placed with the use ofa clear interproximal matrix (Contact Molar Bands, Vivadent USA) and anatomically formed wooden wedges, Each of the four composite materials was placed incrementally with a composite syringe (Centrix Inc. Stratford, CT, USA) after etching the enamel for 30 s with a gel etchant and placing a thin layer of the bonding agent supplied by the manufacturer. The composite placed in the proximal boxes of Class II preparations was polymer±zeal for the manufacturer's recommended time from the lingual, then from the buccal, and lastly from the occlusal direction. The occlusal surfaces of both Class I and Class II restorations and the buccal and lingual interproximal cavosurfaces were finished using 12fluted finishing burs and "Sof-lex" discs (3M Dental Products Division, St. Paul, MN, USA). Sof-Lexinterproximal finishing strips were also used to help establish interproximal contour. Collection of Data. The restorations were evaluated at baseline, 3, 6, 12, 24 and 36 months. This evaluation included the indirect assessment of occlusal wear through the use of stone replicas made from vinyl polysiloxane ("Express", 3M Dental Products Division) impressions of the experimental teeth. These replicas were independently scored by two examTABLE 1: SAMPLESIZEBYTOOTHAND CAVITYTYPEAT PLACEMENT
Material
Hetiomolar J&J Exp Marathon P-30 Total
Premolars Class l ClassII -1 2 -3
6 21 13 8 48
Molars Class l Classll 5 5 8 4 22
10 30 18 15 73
Total 21 57 41 27 146
TABLE 2: MEANOCCLUSALWEAR (pm) FORALL MATERIALS Recall Total Heliomolar J&J Exp Marathon P-30 Signif. (months) n p
