Clinical Comparison of Proximal Contacts Obtained with Different Matrix Systems

Objectives: The aim of this clinical randomized single blind study was to investigate in vivo the proximal contact tightness (PCT) of direct posterior composite resin restorations obtained with two different matrix systems before, directly after treatment and after a period of two weeks.

Methods: 85 consecutive patients without periodontitis being in need of a Class II direct resin restoration were randomly assigned to two groups. Group I (n = 45) was treated with a circumferential matrix system (Tofflemire, Produits Dentaire SA, Vevey, Switzerland). Group II (n = 40) with a sectional matrix system (Palodent Matrix System, Dentsply International Inc. Milford, DE). Proximal contact tightness was measured in Newton using a modified Tooth Pressure Meter (Dörfer et al. (2000)) directly before (T1), after (T2) restoration placement and after a period of two weeks (T3) at the site of treatment as well as at corresponding teeth in the contralateral quadrant as control. Differences over time were tested by ANOVA followed by the post hoc Scheffé-test and differences between the two groups by the T-test for independent variables (p=0.05).

Results: Group I effected an average reduction of PCT from 4.41 N ± 3.06 N (T1) to 2.95 N ± 1.66 N (T2) and 3.47 N ± 1.71 N (T3) (p<0.05), whereas Group II lead to an average increase of PCS from 4.31 ± 2.60 N (T1) to 5.65 N ± 2.63 N (T2) and 5.14 ± 2.05 N (T3) (p<0.05). Differences of PCT between the groups were statistically significant directly after treatment as well as two weeks later (p<0.05).

Conclusions: Use of traditional circumferential matrix systems without a separation ring will lead to a significant loss in PCT, whereas the use of sectional matrix systems combined with separation rings will lead to an increase of PCT.