Cuspal movement and microleakage in premolar teeth restored with resin-based filling materials cured using a 'soft-start' polymerisation protocol

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

Abstract

Objectives. To investigate the effect ofpolymerisation shrinkage strain offour posterior filling materials on cuspal movement, degree of conversion (DC) and cervical gingival microleakage of mesio-occlusal-distal (MOD) restorations placed incrementally in maxillary premolar teeth using a 'soft-start' polymerisation protocol. Methods. Forty sound extracted upper premolar teeth were subjected to stanclardised preparation of a large MOD cavity before restoration. A 'soft-start' polymerisation curing regimen was used and each posterior filling material was placed in eight increments with the appropriate bonding system. A twin channel deflection measuring gauge allowed a measurement of individual cusp deflections at each stage of polymerisation. Restored teeth were thermocycled before immersion in a 0.2% basic fuchsin dye for 24h. After sagittal sectioning of the restored teeth in a mesio-distal plane, the sectioned restorations were examined to assess cervical microleakage. The DC was also assessed using a diffuse-reflectance accessory on a Fourier transform infra-red spectrophotometer. Results. A significant increase in cuspal movement recorded for Z100 (20.06 4.71) compared with Filtek Z250 (TM) (16.52 +/- 3.26), P60 (14.23 +/- 3.71) and Admira (11.11 +/- 2.47). No significant reduction in cuspal movement was identified when compared with a previous study [6] where a full-intensity standard polymerisation protocol was employed. No significant differences were also identified between the materials when the cervical gingival microleakage scores or DC were examined for the'soft-start' compared with the standard polymerisation protocol. Conclusions. Although material type remained a significant factor, the use of a 'soft-start' polymerization compared with a standard curing regime did not offer any significant reduction in associated cuspal movement, DC or gingival microleakage at the cervical dentine cavosurface margin of the cavities restored with the resin-based filling materials. (c) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Details

Original languageEnglish
Pages (from-to)637 - 643
Number of pages7
JournalDental Materials
Volume23
Issue number5
Publication statusPublished - 1 Jan 2007

Keywords

  • gingival microleakage, ormocer, soft-start polymerisation, resin-based composite, cuspal movement