A two-year clinical study of light-cured composite and amalgam restorations in primary molars M. Barr-Agholme 1 A. Od6n = G. Oahll6f 1 T. Mode6r 1 Departments of PedodonticsI and Dental Materials and Technology2 School of Dentistry Karolinska Institutet Box 4064 141 04 Huddinge, Sweden
Received May 30, 1990 Accepted July 12, 1991
Dent Mater7:230-233,October, 1991
Abstract--The object of this prospective study was to compare the clinical behavior of composite and amalgam restorations with respect to anatomical form, marginal adaptation, caries adjacent to margin, and post-operative sensitivity. We selected children (n = 43) with an average age of 6.4 yr exhibiting proximal caries lesions in primary molars distributed on both left and right sides. In each child, one amalgam and one composite side were randomly chosen, resulting in 64 fillings for composite and 55 for amalgam. After a two-year period, significantly (p < O.Ob=) more composite fillings (88%) were clinically classified as satisfactory compared with amalgam fillings (68%). No significant relationship was found between the success rate of proximal fillings and the caries activity of the individuals. The results indicate that composite can be used successfully as a class II filling material in primary molars in children.
ince amalgam exhibits undesirable aesthetic qualities, the use of composite has steadily increased during the past 20 years (Hendriks et al., 1986). Several clinical studies which have recentlybeen presented have shown a high success rate of class II composite restorations over a three-to-five-year period (Bevan and Braham, 1989; Lundin and Koch, 1989; Lundin et al., 1990; Sturdevant et al., 1988). However, subsequent long-term observations of composite fillings in the permanent dentition revealed a high rate ofocclusal wear (Phillips et al., 1973; Boksman et al., 1986; Heyman et al., 1986; Sturdevant et al., 1990; Lundin et al., 1990; Wendell and Vann, 1988) as well as post-operative sensitivity (Boksman etal., 1986; Hendriksetal., 1986; Lundin et al., 1990). Numerous studies have clinically evaluated the use of composites in the primary dentition (Mack, 1970; Leifler and Varpio, 1978; Tonn et al., 1980; Nelson et al., 1980; Leinfelder and Vann, 1982; Roberts et al., 1985; Oldenburg et al., 1985, 1987a, b; Vann et al., 1988; Wendell and Vann, 1988). Contradicting results have been reported from studies comparingthe clinical success of composite and amalgam in primary molars. More composite restorations had to be replaced in primary molars compared with amalgam during a twoyear study (Tonn et al., 1980), whereas Roberts et al. (1985 ) and Oldenburget al. (1987b)reported no statistical difference in clinical performance between composite and amalgam filling in primary posterior teeth. There is a lack of clinical studies where the success rate of class II fillings is related to caries activity in children. Thus, the purpose ofthis prospective study was to compare the clinical behavior of amalgam and composite as class II restorations in primary molars in relation to caries activity in children.
S
MATERIALS AND METHODS
Out of 600 children examined at the Department of Pedodontics, 43 children
230 Barr-Agholme et al. ~Light-cured composite and amalgam restorations in primary molars
were selected because they exhibited proximal caries lesions in primary molars distributed on both right and left sides. The mean age of the children (25 boys and 18 girls) was 6.4 yr. The number of decayed (d) and filled (f) surfaces was determined based on a clinical examination (Koch, 1967) as well as on bitewing radiographs taken bilaterally by use of standardized techniques. Manifest caries lesions were registered when the radiolucent zone on the radiographs had reached into the dentin, corresponding to grade 03 according to GrSndahl et al. (1977). The children were examined every six mo and given a preventive program consisting of professional tooth-cleaning and topical fluoride varnish treatment (Duraphat, Woelm, ICI, Pharmaceutical Eschwege, Germany). Based on clinical and radiographic examinations, a total number of 119 lesions was in need ofrestorations, which were performed by two of the authors (AO andMB). Conventionalnon-beveled mesial or distal class II cavities were prepared in primary molars. Earlier filling material was removed during cavity preparation. All gingival margins were surrounded by enamel. A microthin (0.0015") matrix band was used for all preparations. The cavity was cleaned with Tubulicid (Dental Therapeutics AB, Nacka, Sweden). In every child, one amalgam and one composite side were randomly chosen, resulting in 64 fillings for composite and 55 for amalgam. The cavities used for amalgam were isolated with Tubulitec (Dental Therapeutics AB, Nacka, Sweden), and in deep cavities, Dycal (L.D. Caulk Co., Milford, DE) was used. The amalgam fillings (Dispers alloy, Lee Pharmaceuticals Corp., South E1 Monte,CA) were made by a conventionaltechnique and polished after one wk. The amalgam fillings had to be adjusted with polishing to prevent fractures at each evaluation time. The pulpal and axial walls of the composite preparations were covered with a lining of Dycal. The etching gel (37% phosphoric acid) was applied to the enamel walls of the preparation
with a fine brush for 15 s, and thereafter water-sprayed away for 30 s, and the preparation was dried with compressed air. Contamination by saliva was avoided by the use of cotton rolls, compressed air, and salivary-suction after good patient cooperation was obtained. The cavity walls were covered with a thin layer of dentin adhesive (Scotchbond, 3M Co., St. Paul, MN) and light-cured (Visilux 2@, 3M Dental Products) for 15 s. The composite (P30, 3M) was inserted into the cavities in three increments, starting with the proximal box, and each increment was cured for 60 s. After the matrix band was removed, the fillings were light-cured from buccal and lingual sides for 30 s. The occlusion was tested with occlusion foil (GHM Hanel Medizinal, Niirtingen, Germany). The fillings were then adjusted with a diamond finishing bur and polished with a series of progressively fine disks (Soflex discs, 3M). All fillings were photographed with a Yashica Medical Camera 100, lens 100 mm:4. At baseline, one year, and two years, the clinical performances of the restorations were evaluated simultaneously by two ofthe authors (MB, AO). Bitewing radiographs were taken at each annual check, and the restorations were recorded on color slides. The restorations were clinically evaluated for anatomic form, marginal adaptation, caries adjacent to margin, and post-operative sensitivity. The resin composites were also evaluated for color match and marginal discoloration. The restorations were rated as alfa, bravo, or charlie, corresponding to condition classified as no change, changed but acceptable, or changed and unacceptable, respectively. For anatomic form, marginal adaptation, caries adjacent to margin, color-matching, and marginal discoloration, standard criteria are used (USPHS guidelines; Cvar and Ryge, 1971). However, the anatomic form was excluded, since children of this age group have physiological abrasion of the teeth. Postoperative sensitivity was defined as absent at re-call (alfa), present but not requiring replacement(bravo), or present and requiringreplacement (charlie). The rating for post-operative sensitivity was made on the basis of interpretation of patient's response to a general question concerning any problems with any of the teeth. This question was carefully
TABLE 1
THE REASONFOR PROXIMALFILLINGSNOT RE-EXAMINEDAT "I'WOYEARS'FOLLOW-UP Recurrent Caries
Fracture
Tooth Exfoliated
PatientMoved
Composite (n = 12)
5
1
3
3
Amalgam (n = 21)
7
7
4
3
TABLE 2
RESTORATIONSEVALUATEDBY USPHSSYSTEM alfa
alfa or bravo
alfa or bravo
Baseline
1 year
2 years
100% (64/64)
98% (62/63)
100% (52/52)
Marginal discoloration 100%(64/64)
97% (61/63)
96% (51/52)
Margindegradation
100% (64/64)
97% (61/63)
94% (49/52)
Secondarycaries
100% (64/64)
95% (60/63)
94% (49/52)
Margindegradation
100% (55/55)
80% (43/54)
66% (23/34.)
Secondarycaries
100% (55/55)
94% (51/54)
91% (31/34)
Composite: Colormatch
Amalgam:
*Chi2test; levels of significance,p < 0.05. TABLE 3
COMPARISONOF COMPOSITEvs. AMALGAMEVALUATEDBY USHPSSYSTEM IN TERMSOF PATIENTVARIABLES alfa
alfa or bravo
alfa or bravo
Baseline
1 year
2 years
100% (47/47)
91% (42/46)
89% (33/37)
Second molars
100% (17/17)
68% (15/17)
87% (13/15)
Total
100% (64/64)
90% (57/63)
88% (46/52)
First molars
100% (43/43)
74% (31/42)
68% (19/28)
Second molars
100% (12/12)
75% (9/12)
67% (4/6)
Total
100% (55/55)
74% (40/54)
68% (23/34)
Tooth Effects Composite: First molars
Amalgam:
Age Effects
2 years
Composite: Age 4-6
80% (24/36)
Age 7-8
100% (22/22)
Age 4-6
63% (15/24)
Age 7-8
80% (8/10)
Amalgam:
*ChFtest; levels of significance,p < 0.05.
phrased so as not to elicit a false-positive response. For statistical analysis of the results in frequencies between groups, the Chisquare test was used.
RESULTS
The total mean number of decayed and filled surfaces at baseline was 7.3 (SD, 4.3), whereas the corresponding value for proximal surfaces was 4.2 (SD, 2.1).
Dental Materials~October 1991 231
At the start of the study, the total mean number of new caries lesions in the children was 4.2 (SD, 3.5). The mean caries increment among the children during the first year of the study was 1.8 new lesions and 1.2 during the second year. Out of 119 originally proximal fillings performed, 86 (72%) could be reexamined after two years. The rest of the fillings (n = 33) were not available, and the reasons are shown in Table 1. The numbers of proximal fillings classifted as alfa or bravo in the children during the two-year study are presented in Table 2. After two years, 88% of the composite fillings were classified as alfa or bravo, compared with 68% of theamalgam restorations (Table 3 ). This difference was statistically significant (p < 0.05). The results of the evaluation ofoperatingcategories for each material at each evaluation time are presented in Table 2. The color match of the composites at baseline and years 1 and 2 is shown in Table 2. After two years, 94% of the composite fillings were classified as alfa and the others (6%) as bravo. The results of evaluation of marginal discoloration of the composite fillings are also shown in Table 2. Two fillings were evaluated as charlie at year one and one filling at year two. At the two-year evaluation period, 68% of the amalgam fillings showed no degradation with respect to marginal adaptation (rating as alfa or bravo), as compared with 94% of the composite (Table 2). This difference was statistically significant (p < 0.05). Caries adjacent to margin was observed in three amalgam fillings out of 34 (9%) and in three composite fillings out of 52 (6%) at the two-year follow-up (Table 2). Neither the caries activity during the evaluation period nor the age of the children when the fillings were performed significantly influenced the success rate of proximal fillings (Table 3). There was no statistically significant differencein success between the fillings performed on the first primary molar compared with those performed on the second primary molar. Among the composite fillings, there was no post-operative sensitivity to report.
DISCUSSION This study shows that the success rate for composite class II fillingsin primary
molars in children was significantly higher (p < 0.05) than for amalgam class II fillings. Neither the age nor the caries activity Significantly influenced the success rate of proximal fillings. It must be considered that the children in this study were not randomly chosen, since they all had at least two proximal lesions in need of restorative treatment. Therefore, these patients represent a group with a high caries activity at the start of the study. With a prophylaxis program consisting of professional tooth-cleaning and use of topical fluoride varnish application, the caries activity decreased during the twoyear period, from 4.2 to 1.2 new lesions per year. At the two-year follow-up, the caries increment was of approximately the same magnitude as that reported among eight-year-oldchildren in Sweden (Stecksdn-Blicks, 1987). In our study, a rather high failure rate in class II amalgam restorations in primary molars was noticed, which may to some extent explain the high proportion of clinically unacceptable proximal fillings as a whole during the two-year period. Most of these failures were caused by fractures in the isthmus area, which is in agreement with earlier reports (Varpio, 1980; Quist et al., 1986; Levering and Messer, 1988). It has also been previously reported by Holland et al. (1986) that the survival time for amalgam restorations in deciduous molars is rather limited, corresponding to approximately 44 months for children aged 7-8 yr. After two years, significantly more composite fillings were classified as satisfactory compared with amalgam fillings among the children. This is in contrast to Tonn et al. (1980), Oldenburg et al. (1987b), and Roberts et al. (1985), who showed no statistically significant difference between the success rates for composite and amalgam fillings. However, according to Tonn et al. (1980) and Nelson et al. (1980), the anatomic form of amalgam fillings was significantly better compared with. that of chemically cured composite restorations. When analyzing our results, that showed a higher success rate for composite compared with amalgam fillings, one must consider that amalgam restorations are more susceptible to stresses of occlusion when the tooth becomes abraded. Therefore, the greater occlusal wear of the composite fillings in comparison with amalgam seems to be an advantage,
232 Barr-Ag,holme et al, ~Light-cured composite and amalgam restorations in primary molars
since the wear of the composite is of almost the same magnitude as the natural occlusal wear of the primary tooth. Another factor of importance is that the new light-cured posterior composite materials have improved, which may to some extent explain the comparatively better clinical results for composites. We did not find any difference in success rates between amalgam and composite in children with different caries activity. However, there are no reports available in the literature concerning the influence of caries activity on the success rate of fillings. In conclusion, the results of this study indicate that composite can be an acceptable alternative as a class II filling material in children.
REFERENCES
BEVAN,F.L. and BRAHAM,R.L. (1989): Clinical Evaluation of the Handling Properties of Herculite in Posterior Primary Teeth, Am J Dent 2:17-20.
BOKSMAN, L.;JORDAN, R.; SUZUKI, M.; and CHARLES, D. (1986): A Visible Lightcured Posterior Composite Resin: Results of a 3-year Clinical Evaluation,J A m Dent Assoc 112:627-631. CVAR, J.F. and RYGE, G. (1971): Criteria for the Clinical Evaluation of Dental Restorative Materials. USPHS Publ. No. 790-244. San Francisco: US Government Printing Office.
GRONDAHL,
H.G.; HOLLENDER,
L.;
MALMCRONA, E.; and SUNDQmST, B. (1977): Dental CariesinTeenagers. I. Index and Score System for Radiographic Studies ofProximal Surfaces, Swed Dent J 1:45-50. HENDRIKS,F.H.; LETZEL, H.; andVRIJHOEF, M. (1986): Composite versusAmalgam Restorations in Three-year ClinicaIEvaluation,JOraIRehabi113:401411. HEYm~, H.O.; WILDER, A.D.; MAY, K.N.; and LEINFELDER, K.F. (1986): Twoyear Clinical Study of Composite Resins in Posterior Teeth, Dent Mater 2:37-41. HOLLAND, I.S.;WALLS,A.W.G.;WALLWOZK, M.A.; and MtrRRA£, J.J. (1986): The Longevity of Amalgam Restoration in Deciduous Molars, Br Dent J 162:255-258. KOCH, G. (1967): Effect of Sodium Fluoride in Dentifrice and Mouthwash on Incidence of Dental Caries in School Children. Thesis, Odontol Revy 18 (Suppl 12).
LEIFLER, E. and VARPIO, M. (1978): Proximoclusal Composite Restoration in Primary Molars: a Two-year Follow-up, J Dent Child 48:411-416. LEINFELDER,K.F. and VANN,W.F. (1982): The Use of Composite Resins in Primary Molars, Ped Dent 4:27-31. LEVERING,N.J. and MESSER,L.B. (1988): The Durability of Primary Molar Restorations: I. Observation and Predictions of Success of Amalgam, Ped Dent 10:74-80. o
LUNDIN,S.A.; ANDERSSON,B.; KOCH,G.; and RASMUSSZN,C.G. (1990): Class II Composite Resin Restorations: A Three-year Clinical Study of Six Different Posterior Composites, Swed Dent J 14:105-114. LUNDn~,S.A. and KOCH,G. (1989): Class I and II Composite Resin Restorations: A 4-year Clinical Follow-up, Swed Dent J 13:217-277. MACK, E.S. (1970): A Restorative Pedodontic Practice without Amalgam, J Dent Child 37:428-434. NELSON, G.;OSBORN, J.;GALE,E.;NORMAN, R.;and PmLLIPS,R.W. (1980):AThreeyear ClinicalEvaluation of Composite Resin and a High Copper Amalgam in Posterior Primary Teeth, J
Dent Child 47:414-418. OLDENBURG,T.R.;VANN,W.F.; and DILLZY, D.C. (1985): Composite Restoration for Primary Molars: Two-year Results, Ped Dent 7:96-103. OLDEN~URG,T.R.;VANN,W.F.; andDmLzY, D.C. (1987a): Composite Restorations for Primary Molars: Results after Four Years, Ped Dent 9:136-143. OLDENBURG,T.R.;VANN,W.F.; andDmLEY, D.C. (1987b): Comparison of Composite and Amalgam in Posterior Teeth of Children, Dent Mater 3:182186. PHILLIPS,R.W.; AVERY, D.R.; MEHRA, R.; SWARTZ, M.L.; and McCuNz, R.J. (1973): Observationson a Composite Resin forClass IIRestoration. Threeyear Report,J ProsthetDent 30:891897. QVIST, V.; THYLSTRUP, A.; and MJOR, I.A. (1986): Restorative Treatment Pattern and Longevity of Amalgam Restoration in Denmark, Aeta Odontol Scand 44:343-349. ROBERTS,M.W.;MOFFA,J.P.; and BRORINO, C.L. (1985): Two-year Clinical Evaluation of a Proprietary Composite Resin for Restoration of Primary Posterior Teeth, Ped Dent 7:14-18.
STECKSEN-BLICKS,C. (1987): Lactobacilli and Streptococcus mutans in Saliva, Diet and Caries Increment in 8- and 13-year-old Children, Scand J Dent Res 95:18-26. STURDEVANT, J.R.;LUNDEEN, T.F.;SLUDER, T.B., Jr.;WILDER, A.D.; and TAYLOR, D.F. (1988):Five-yearStudyofTwo Light-cured Posterior Composite Resins, Dent Mater 4:105-110. To~rN,E.M.; RYGE, G.; and CHAMBERS, D. (1980): A Two-year ClinicalStudy of a Carvable Composite Resin Used as Class II Restoration in Primary Molars,J Dent Child 47:405-413. VANN, W.F.; BARKMEIER, W.W.; and MAHLER, D.B. (1988):Assessing Composite Resin Wear in Primary Molars:Four-year Findings, J Dent Res 67:876-879. VARPIO, M. (1981): Caries Prevalence and Therapy in the Deciduous Dentitionfrom 3 to 8 Years,Acta Odontol Scand 39:307-312. WENDELL, J.J. and VAMP, W.F. (1988): Wear of Composite Resin Restorations in Primary versus Permanent Molar Teeth, J Dent Res 67:71-74.
Dental Materials~October 1991 233
Received May 30, 1990 Accepted July 12, 1991
Dent Mater7:230-233,October, 1991
Abstract--The object of this prospective study was to compare the clinical behavior of composite and amalgam restorations with respect to anatomical form, marginal adaptation, caries adjacent to margin, and post-operative sensitivity. We selected children (n = 43) with an average age of 6.4 yr exhibiting proximal caries lesions in primary molars distributed on both left and right sides. In each child, one amalgam and one composite side were randomly chosen, resulting in 64 fillings for composite and 55 for amalgam. After a two-year period, significantly (p < O.Ob=) more composite fillings (88%) were clinically classified as satisfactory compared with amalgam fillings (68%). No significant relationship was found between the success rate of proximal fillings and the caries activity of the individuals. The results indicate that composite can be used successfully as a class II filling material in primary molars in children.
ince amalgam exhibits undesirable aesthetic qualities, the use of composite has steadily increased during the past 20 years (Hendriks et al., 1986). Several clinical studies which have recentlybeen presented have shown a high success rate of class II composite restorations over a three-to-five-year period (Bevan and Braham, 1989; Lundin and Koch, 1989; Lundin et al., 1990; Sturdevant et al., 1988). However, subsequent long-term observations of composite fillings in the permanent dentition revealed a high rate ofocclusal wear (Phillips et al., 1973; Boksman et al., 1986; Heyman et al., 1986; Sturdevant et al., 1990; Lundin et al., 1990; Wendell and Vann, 1988) as well as post-operative sensitivity (Boksman etal., 1986; Hendriksetal., 1986; Lundin et al., 1990). Numerous studies have clinically evaluated the use of composites in the primary dentition (Mack, 1970; Leifler and Varpio, 1978; Tonn et al., 1980; Nelson et al., 1980; Leinfelder and Vann, 1982; Roberts et al., 1985; Oldenburg et al., 1985, 1987a, b; Vann et al., 1988; Wendell and Vann, 1988). Contradicting results have been reported from studies comparingthe clinical success of composite and amalgam in primary molars. More composite restorations had to be replaced in primary molars compared with amalgam during a twoyear study (Tonn et al., 1980), whereas Roberts et al. (1985 ) and Oldenburget al. (1987b)reported no statistical difference in clinical performance between composite and amalgam filling in primary posterior teeth. There is a lack of clinical studies where the success rate of class II fillings is related to caries activity in children. Thus, the purpose ofthis prospective study was to compare the clinical behavior of amalgam and composite as class II restorations in primary molars in relation to caries activity in children.
S
MATERIALS AND METHODS
Out of 600 children examined at the Department of Pedodontics, 43 children
230 Barr-Agholme et al. ~Light-cured composite and amalgam restorations in primary molars
were selected because they exhibited proximal caries lesions in primary molars distributed on both right and left sides. The mean age of the children (25 boys and 18 girls) was 6.4 yr. The number of decayed (d) and filled (f) surfaces was determined based on a clinical examination (Koch, 1967) as well as on bitewing radiographs taken bilaterally by use of standardized techniques. Manifest caries lesions were registered when the radiolucent zone on the radiographs had reached into the dentin, corresponding to grade 03 according to GrSndahl et al. (1977). The children were examined every six mo and given a preventive program consisting of professional tooth-cleaning and topical fluoride varnish treatment (Duraphat, Woelm, ICI, Pharmaceutical Eschwege, Germany). Based on clinical and radiographic examinations, a total number of 119 lesions was in need ofrestorations, which were performed by two of the authors (AO andMB). Conventionalnon-beveled mesial or distal class II cavities were prepared in primary molars. Earlier filling material was removed during cavity preparation. All gingival margins were surrounded by enamel. A microthin (0.0015") matrix band was used for all preparations. The cavity was cleaned with Tubulicid (Dental Therapeutics AB, Nacka, Sweden). In every child, one amalgam and one composite side were randomly chosen, resulting in 64 fillings for composite and 55 for amalgam. The cavities used for amalgam were isolated with Tubulitec (Dental Therapeutics AB, Nacka, Sweden), and in deep cavities, Dycal (L.D. Caulk Co., Milford, DE) was used. The amalgam fillings (Dispers alloy, Lee Pharmaceuticals Corp., South E1 Monte,CA) were made by a conventionaltechnique and polished after one wk. The amalgam fillings had to be adjusted with polishing to prevent fractures at each evaluation time. The pulpal and axial walls of the composite preparations were covered with a lining of Dycal. The etching gel (37% phosphoric acid) was applied to the enamel walls of the preparation
with a fine brush for 15 s, and thereafter water-sprayed away for 30 s, and the preparation was dried with compressed air. Contamination by saliva was avoided by the use of cotton rolls, compressed air, and salivary-suction after good patient cooperation was obtained. The cavity walls were covered with a thin layer of dentin adhesive (Scotchbond, 3M Co., St. Paul, MN) and light-cured (Visilux 2@, 3M Dental Products) for 15 s. The composite (P30, 3M) was inserted into the cavities in three increments, starting with the proximal box, and each increment was cured for 60 s. After the matrix band was removed, the fillings were light-cured from buccal and lingual sides for 30 s. The occlusion was tested with occlusion foil (GHM Hanel Medizinal, Niirtingen, Germany). The fillings were then adjusted with a diamond finishing bur and polished with a series of progressively fine disks (Soflex discs, 3M). All fillings were photographed with a Yashica Medical Camera 100, lens 100 mm:4. At baseline, one year, and two years, the clinical performances of the restorations were evaluated simultaneously by two ofthe authors (MB, AO). Bitewing radiographs were taken at each annual check, and the restorations were recorded on color slides. The restorations were clinically evaluated for anatomic form, marginal adaptation, caries adjacent to margin, and post-operative sensitivity. The resin composites were also evaluated for color match and marginal discoloration. The restorations were rated as alfa, bravo, or charlie, corresponding to condition classified as no change, changed but acceptable, or changed and unacceptable, respectively. For anatomic form, marginal adaptation, caries adjacent to margin, color-matching, and marginal discoloration, standard criteria are used (USPHS guidelines; Cvar and Ryge, 1971). However, the anatomic form was excluded, since children of this age group have physiological abrasion of the teeth. Postoperative sensitivity was defined as absent at re-call (alfa), present but not requiring replacement(bravo), or present and requiringreplacement (charlie). The rating for post-operative sensitivity was made on the basis of interpretation of patient's response to a general question concerning any problems with any of the teeth. This question was carefully
TABLE 1
THE REASONFOR PROXIMALFILLINGSNOT RE-EXAMINEDAT "I'WOYEARS'FOLLOW-UP Recurrent Caries
Fracture
Tooth Exfoliated
PatientMoved
Composite (n = 12)
5
1
3
3
Amalgam (n = 21)
7
7
4
3
TABLE 2
RESTORATIONSEVALUATEDBY USPHSSYSTEM alfa
alfa or bravo
alfa or bravo
Baseline
1 year
2 years
100% (64/64)
98% (62/63)
100% (52/52)
Marginal discoloration 100%(64/64)
97% (61/63)
96% (51/52)
Margindegradation
100% (64/64)
97% (61/63)
94% (49/52)
Secondarycaries
100% (64/64)
95% (60/63)
94% (49/52)
Margindegradation
100% (55/55)
80% (43/54)
66% (23/34.)
Secondarycaries
100% (55/55)
94% (51/54)
91% (31/34)
Composite: Colormatch
Amalgam:
*Chi2test; levels of significance,p < 0.05. TABLE 3
COMPARISONOF COMPOSITEvs. AMALGAMEVALUATEDBY USHPSSYSTEM IN TERMSOF PATIENTVARIABLES alfa
alfa or bravo
alfa or bravo
Baseline
1 year
2 years
100% (47/47)
91% (42/46)
89% (33/37)
Second molars
100% (17/17)
68% (15/17)
87% (13/15)
Total
100% (64/64)
90% (57/63)
88% (46/52)
First molars
100% (43/43)
74% (31/42)
68% (19/28)
Second molars
100% (12/12)
75% (9/12)
67% (4/6)
Total
100% (55/55)
74% (40/54)
68% (23/34)
Tooth Effects Composite: First molars
Amalgam:
Age Effects
2 years
Composite: Age 4-6
80% (24/36)
Age 7-8
100% (22/22)
Age 4-6
63% (15/24)
Age 7-8
80% (8/10)
Amalgam:
*ChFtest; levels of significance,p < 0.05.
phrased so as not to elicit a false-positive response. For statistical analysis of the results in frequencies between groups, the Chisquare test was used.
RESULTS
The total mean number of decayed and filled surfaces at baseline was 7.3 (SD, 4.3), whereas the corresponding value for proximal surfaces was 4.2 (SD, 2.1).
Dental Materials~October 1991 231
At the start of the study, the total mean number of new caries lesions in the children was 4.2 (SD, 3.5). The mean caries increment among the children during the first year of the study was 1.8 new lesions and 1.2 during the second year. Out of 119 originally proximal fillings performed, 86 (72%) could be reexamined after two years. The rest of the fillings (n = 33) were not available, and the reasons are shown in Table 1. The numbers of proximal fillings classifted as alfa or bravo in the children during the two-year study are presented in Table 2. After two years, 88% of the composite fillings were classified as alfa or bravo, compared with 68% of theamalgam restorations (Table 3 ). This difference was statistically significant (p < 0.05). The results of the evaluation ofoperatingcategories for each material at each evaluation time are presented in Table 2. The color match of the composites at baseline and years 1 and 2 is shown in Table 2. After two years, 94% of the composite fillings were classified as alfa and the others (6%) as bravo. The results of evaluation of marginal discoloration of the composite fillings are also shown in Table 2. Two fillings were evaluated as charlie at year one and one filling at year two. At the two-year evaluation period, 68% of the amalgam fillings showed no degradation with respect to marginal adaptation (rating as alfa or bravo), as compared with 94% of the composite (Table 2). This difference was statistically significant (p < 0.05). Caries adjacent to margin was observed in three amalgam fillings out of 34 (9%) and in three composite fillings out of 52 (6%) at the two-year follow-up (Table 2). Neither the caries activity during the evaluation period nor the age of the children when the fillings were performed significantly influenced the success rate of proximal fillings (Table 3). There was no statistically significant differencein success between the fillings performed on the first primary molar compared with those performed on the second primary molar. Among the composite fillings, there was no post-operative sensitivity to report.
DISCUSSION This study shows that the success rate for composite class II fillingsin primary
molars in children was significantly higher (p < 0.05) than for amalgam class II fillings. Neither the age nor the caries activity Significantly influenced the success rate of proximal fillings. It must be considered that the children in this study were not randomly chosen, since they all had at least two proximal lesions in need of restorative treatment. Therefore, these patients represent a group with a high caries activity at the start of the study. With a prophylaxis program consisting of professional tooth-cleaning and use of topical fluoride varnish application, the caries activity decreased during the twoyear period, from 4.2 to 1.2 new lesions per year. At the two-year follow-up, the caries increment was of approximately the same magnitude as that reported among eight-year-oldchildren in Sweden (Stecksdn-Blicks, 1987). In our study, a rather high failure rate in class II amalgam restorations in primary molars was noticed, which may to some extent explain the high proportion of clinically unacceptable proximal fillings as a whole during the two-year period. Most of these failures were caused by fractures in the isthmus area, which is in agreement with earlier reports (Varpio, 1980; Quist et al., 1986; Levering and Messer, 1988). It has also been previously reported by Holland et al. (1986) that the survival time for amalgam restorations in deciduous molars is rather limited, corresponding to approximately 44 months for children aged 7-8 yr. After two years, significantly more composite fillings were classified as satisfactory compared with amalgam fillings among the children. This is in contrast to Tonn et al. (1980), Oldenburg et al. (1987b), and Roberts et al. (1985), who showed no statistically significant difference between the success rates for composite and amalgam fillings. However, according to Tonn et al. (1980) and Nelson et al. (1980), the anatomic form of amalgam fillings was significantly better compared with. that of chemically cured composite restorations. When analyzing our results, that showed a higher success rate for composite compared with amalgam fillings, one must consider that amalgam restorations are more susceptible to stresses of occlusion when the tooth becomes abraded. Therefore, the greater occlusal wear of the composite fillings in comparison with amalgam seems to be an advantage,
232 Barr-Ag,holme et al, ~Light-cured composite and amalgam restorations in primary molars
since the wear of the composite is of almost the same magnitude as the natural occlusal wear of the primary tooth. Another factor of importance is that the new light-cured posterior composite materials have improved, which may to some extent explain the comparatively better clinical results for composites. We did not find any difference in success rates between amalgam and composite in children with different caries activity. However, there are no reports available in the literature concerning the influence of caries activity on the success rate of fillings. In conclusion, the results of this study indicate that composite can be an acceptable alternative as a class II filling material in children.
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