Skip to main content
. Author manuscript; available in PMC: 2011 Oct 1.
Published in final edited form as: J Dent Res. 2010 Jul 26;89(10):1039–1044. doi: 10.1177/0022034510375286

Figure 2.

Figure 2

Figure 2

Intra-articular microparticles did not induce TMJ pain, based on (a) meal duration, and (b) food intake measurements for two days prior and six days following intra-articular injection of 15, 30, or 50 mg/mL PLGA microparticle formulations (abbreviated “PLGA”). A dashed line indicates the time of injection. The upper panels of both (a) and (b) depict the two control groups, consisting of rats that did not receive any injections (“No injection”), and rats where only the carrier fluid was injected (“0 mg/mL PLGA”). (a) Meal duration differed significantly between the 0 mg/mL PLGA group and both the 15 mg/mL PLGA and 50 mg/mL PLGA groups (p < 0.05; indicated by #). However, none of the groups differed from the “No injection” negative control (p > 0.05). Meal duration data from a previous study where rat TMJ inflammation was induced via bilateral injection of a pro-inflammatory agent (15 μg CFA/joint; “Inflamed TMJ *” group) are included in (a) for comparison. In that study, a significant increase (p < 0.05) in meal duration was observed compared to the baseline pre-injection value (Bellinger et al., 2007). None of the groups in this study showed a significant increase in meal duration compared to baseline (p > 0.05). (b) Food intake differed significantly (p < 0.05) between the 30 mg/mL PLGA group and both the 15 mg/mL PLGA experimental group and the 0 mg/mL PLGA control group. However, none of the groups differed from the “No injection” negative control (p > 0.05). Food intake results from a previous study where rat TMJ inflammation was induced via bilateral injection of a pro-inflammatory agent (300 μg CFA/joint; “Inflamed TMJ *” group) are included in (b) for comparison. In that study, a significant decrease (p < 0.05) in food intake was observed compared to the baseline pre-injection value (Harper et al., 2000). None of the groups in the present study showed a significant decrease in food intake compared to the baseline values (p > 0.05). Values for each group are expressed as a percentage of the average pre-injection value. Data points represent the mean ± standard error of the mean for n = 8 rats (or n = 3 rats in the “No injection” group). Error bars are included for all groups, though they are too small to resolve in some cases. Groups that differ significantly (p < 0.05) from “0 mg/mL PLGA” are indicated by #.