Proximo‐cervical adaptation of Class II‐composite restorations after thermocycling: a quantitative and qualitative study

Abstract

Sixty caries-free extracted human molars were used to determine the proximo-cervical adaptation and sealing of Class Il-composite restorations related to the location of the cavity margins: 1-0 mm or 0-5 mm coronal to the cementum-enamel-junction (CEJ), at the CEJ, and 0-5 mm apical to the CEJ. All cavities were filled w^ith a hybride type composite resin, w^hich w^as combined at the CEJ and apical to the CEJ w^ith a dentine adhesive in half of the specimens. The proximo-cervical adaptation and sealing was determined before and after thermocycling (TC, 2000 cycles, 5-55 °C) by SEM and dye penetration tests. Furthermore, an analysis of the interfaces between the enamel or dentine and the filling material was performed to determine whether or not there is a significant correlation between micromorphological factors of the dental hard tissues (enamel acid etch pattern, dentine resin tag pattern) and the marginal adaptation of the composite restorations. The data were statistically evaluated by means of H-tests (Kruskall-Wallis), [/-tests (Mann-Whitney), and Chi^-tests (P<0 05).It was found that the proximo-cervical adaptation is statistically significant dependent on the position of the margin. 1-0 mm coronal to the CEJ an excellent marginal sealing was found before and after TC, whereas all other groups revealed a significant deterioration of the marginal integrity after TC. Using a dentine adhesive significantly improved the marginal sealing in cavities at the CEJ before and after TC, how^ever the marginal quality was not achieved as in the case of the normally structured enamel 1-0 mm coronal to the CEJ follow^ing acid etching. In defects 0-5 mm apical to the CEJ the dentine adhesive only improved the cervical adaptation before TC. The evaluation of the tooth/ filling interfaces revealed that there is no statistically significant correlation between the enamel acid etch pattern resp. dentine resin tag pattern and the marginal sealing.

Marginal microleakage of class II composite resin restorations due to restorative techniques

“…The null hypothesis was not rejected because there were not differences among marginal microleakage of CR with respect to restorative techniques. Although some studies used a smaller number of specimens per group (9,21) or the same amount (17,19) than the present study, our data showed high standard deviation values. It is possible that a larger sample size per group could lead to significant differences, especially in the group 3.…”

“…The class II cavities were confectioned only in one part of the teeth, since the photo-curing of the resin restoration could be to influence the shrinkage stress generation on the restoration of the other side. In class II cavities, another factor that significantly influences the marginal fit is the location of cervical margin (5,17). If the margins are localized around 1.0 mm coronal to the CEJ a good marginal integrity may result following a conventional enamel acid etching (17).…”

Marginal microleakage of class II composite resin restorations due to restorative techniques

“…The null hypothesis was not rejected because there were not differences among marginal microleakage of CR with respect to restorative techniques. Although some studies used a smaller number of specimens per group (9,21) or the same amount (17,19) than the present study, our data showed high standard deviation values. It is possible that a larger sample size per group could lead to significant differences, especially in the group 3.…”

“…The class II cavities were confectioned only in one part of the teeth, since the photo-curing of the resin restoration could be to influence the shrinkage stress generation on the restoration of the other side. In class II cavities, another factor that significantly influences the marginal fit is the location of cervical margin (5,17). If the margins are localized around 1.0 mm coronal to the CEJ a good marginal integrity may result following a conventional enamel acid etching (17).…”

Factors Associated with Microleakage in Class II Resin Composite Restorations

“…28 On the other hand, a study of Class V composite restorations reported similar rankings in enamel for gap size and microleakage assessed by SEM and dye penetration, respectively, but found more inconsistent rankings in dentin. 29 This might partly be explained by the wider biological variation of dentin, leading to a less reliable adhesive bond to resist the effects of polymerization shrinkage and, thus, gap formation. 22 It might also be due to internal void formation.…”

Marginal adaptation in vitro and clinical outcome of Class V restorations

“…Furthermore, a poor or no correlation was found between tracer penetration and SEM analysis of restorative margins (Dietrich et al, 2000;Heintze et al, 2007a;Schuckar and Geurtsen, 1997).…”

Marginal microleakage of class II composite resin restorations due to restorative techniques

“…The null hypothesis was not rejected because there were not differences among marginal microleakage of CR with respect to restorative techniques. Although some studies used a smaller number of specimens per group (9,21) or the same amount (17,19) than the present study, our data showed high standard deviation values. It is possible that a larger sample size per group could lead to significant differences, especially in the group 3.…”

“…The class II cavities were confectioned only in one part of the teeth, since the photo-curing of the resin restoration could be to influence the shrinkage stress generation on the restoration of the other side. In class II cavities, another factor that significantly influences the marginal fit is the location of cervical margin (5,17). If the margins are localized around 1.0 mm coronal to the CEJ a good marginal integrity may result following a conventional enamel acid etching (17).…”

Factors Associated with Microleakage in Class II Resin Composite Restorations

“…28 On the other hand, a study of Class V composite restorations reported similar rankings in enamel for gap size and microleakage assessed by SEM and dye penetration, respectively, but found more inconsistent rankings in dentin. 29 This might partly be explained by the wider biological variation of dentin, leading to a less reliable adhesive bond to resist the effects of polymerization shrinkage and, thus, gap formation. 22 It might also be due to internal void formation.…”

Marginal adaptation in vitro and clinical outcome of Class V restorations

“…Furthermore, a poor or no correlation was found between tracer penetration and SEM analysis of restorative margins (Dietrich et al, 2000;Heintze et al, 2007a;Schuckar and Geurtsen, 1997).…”

Marginal microleakage of class II composite resin restorations due to restorative techniques

“…The null hypothesis was not rejected because there were not differences among marginal microleakage of CR with respect to restorative techniques. Although some studies used a smaller number of specimens per group (9,21) or the same amount (17,19) than the present study, our data showed high standard deviation values. It is possible that a larger sample size per group could lead to significant differences, especially in the group 3.…”

“…The class II cavities were confectioned only in one part of the teeth, since the photo-curing of the resin restoration could be to influence the shrinkage stress generation on the restoration of the other side. In class II cavities, another factor that significantly influences the marginal fit is the location of cervical margin (5,17). If the margins are localized around 1.0 mm coronal to the CEJ a good marginal integrity may result following a conventional enamel acid etching (17).…”

Factors Associated with Microleakage in Class II Resin Composite Restorations

“…28 On the other hand, a study of Class V composite restorations reported similar rankings in enamel for gap size and microleakage assessed by SEM and dye penetration, respectively, but found more inconsistent rankings in dentin. 29 This might partly be explained by the wider biological variation of dentin, leading to a less reliable adhesive bond to resist the effects of polymerization shrinkage and, thus, gap formation. 22 It might also be due to internal void formation.…”

Marginal adaptation in vitro and clinical outcome of Class V restorations

“…Furthermore, a poor or no correlation was found between tracer penetration and SEM analysis of restorative margins (Dietrich et al, 2000;Heintze et al, 2007a;Schuckar and Geurtsen, 1997).…”