Treatment of Class II Caries Lesions with Application of Packable and Conventional Resin Composites: Clinical and Experimental Study

Background: The aim of the present study was to compare the efficacy of packable and conventional composites in treatment of patients with class II caries lesions (CIICLs). Methods and Results: The clinical part of the study was conducted on patients with indications for composite restoration of at least two adjacent CIICCLs. There were 32 patients in whom 72 (36 pairs) teeth with caries pathology were treated. One tooth in every pair was randomly assigned for restoration with Filtek Z250 (Cl-Group 1, n=36) and another one with preheated Filtek-P60 (Cl-Group 2, n=36). The mean observation time for composite restorations was 47.1 +/- 13.8 months. The modified USPHS criteria list was applied for clinical evaluation of the four following clinical parameters, which were used in the study: secondary caries, anatomy form, occlusal contact, and surface texture. The experimental study was conducted on 40 filling samples, which were made of conventional Filtek Z250 (Exp-Group 1, n=20) and packable Filtek P60 (Exp-Group 2, n=20) with the help of a transparent plastic mold. Every experimental group was randomly divided into two subgroups (A and B): polymerized filling samples of Exp-Subgroups 1A (n=10) and 2A (n=10) were put into the test right after polymerization; samples of Exp-Subgroups 1B (n=10) and 2B (n=10) were passed through a shear-strength test after exposure to four consecutive cycles of autoclaving. Shear-strength measurements were made in an Ultratest Machine (Ultradent, USA), which was adapted to perform a proper test. The incidence of secondary caries in both clinical groups (two incidents in Gl-Group 1 and one incident in Cl-Croup 2) was very low, and comparative analysis of obtained results did not reveal any significant difference between them. In relation to criteria of anatomy form, the percentage of alpha level of tooth restorations that were done with packable Filtek P60, was 38.9%. Bravo estimates had 50% of restored teeth. Tooth restorations with conventional Filtek Z250 had alpha level in 58.3% and bravo in 41.7% of cases. Occlusal contact and surface texture, the efficacy of CIICL management was better in teeth that had been treated with packable composite. Analysis of experimental findings revealed that the mean value of shear strength for Filtek P60 filling samples, which were tested immediately after polymerization, was lower than the same parameter for Filtek Z250 on 20.5% (P<0.01). In addition, it was established that the studied parameter for filling samples of Filtek Z250 had decreased by 1.4 times (28.1%) after cycles of autoclaving (P<0.05). A similar tendency was observed for Filtek-P60 too, but only 10.2% showed a decrease in value (P<0.05). Conclusion: Based on obtained clinical findings it can be concluded that treatment of CIICLs with application of packable Filtek P60 and conventional Filtek Z250 does not lead to a recurrence of caries in a period of 47.1 +/- 13.8 months. The issue of more frequent chipping of composite restorations that were made of packable Filtek P60, but not of conventional Filtek Z250, could be of clinical value in treatment planning of patients with excessive occlusal load and tooth wear. In addition, it was clinically noticed that tooth composite restorations made of packable Filtek P60 had values of surface texture that were close to alpha level.