Effects of compression and non-steroidal anti-inflammatory drugs on periodontal fibroblasts

Objectives: There is increasing evidence that non-steroidal anti-inflammatory drugs (NSAIDs) can affect orthodontic tooth movement. The object of the current study was to investigate the changes in human periodontal ligament fibroblasts (HPdLF) when static mechanical compression was applied combined with the presence of aspirin or paracetamol.

Methods: Static compressive force is thought to mimic that found in vivo during orthodontic treatment. HPdLF were cultured in 5 μM aspirin or paracetamol and loaded to static compression force in vitro. Different strengths (1%, 5% and 10%) of SMS were loaded to the HPdLF for 12 hours. Viability was verified by MTT assay. Gene expression of RankL, OPG, ALP and Cyclin D1 were investigated using real-time PCR methods.

Results: Compression with high magnitude (10%) led to a decrease of viability of HPdLF, which was enhanced by presence of paracetamol. RT-PCR showed that static compression of 5% led to triplication of gene expression of RankL and a resulting RankL/OPG ratio >1. HPdLF cultured with aspirin or paracetamol showed a reduced increase of RankL. Osteogenic differentiation (ALP) and proliferation (Cyclin D1)of HPdLF was increased by aspirin and paracetamol, whereas compression without NSAIDs did only increase ALP, but not Cyclin D1.

Conclusions: Static mechanical compression combined with paracetamol decreases viability of HPdLF. Compression forces increase gene expression of HPdLF for bone modification. Aspirin and paracetamol both led to reduced changes of these genes and might lead to a decelerated orthodontic tooth movement.