INTRODUCTION
“Bone remodeling” is a dynamic process and continues throughout life. Osteoblasts and osteoclasts take part in bone formation and the destruction of the bone in this process. The number and activity of osteoclasts and osteoblasts are scheduled by a multitude of factors, such as hormones, cytokines and locally produced signaling molecules under the influence of mechanical stimuli (1-3). Systemic and non-systemic factors that affect bone remodeling are explained in the literature (4). Various systemic and local endocrine and paracrine factors are involved in these processes. One of the most important factors in bone healing is the use of several pharmacological agents (5). Steroids, chemotherapy drugs, and some classes of antibiotics have been reported to have negative effects on bone healing (5). Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed drugs for pain relief and inflammation but have also been found to have a potential to delay and to inhibit fracture healing (5).
The aim of this study was to investigate the indirect effects of dexketoprofen trometamol (DEXT), meloxicam (MEL) and diclofenac sodium (DIC) on alveolar bone when they are used for miscellaneous purposes such as prevention of pain anywhere in the body.
Materials and Methods
The experimental protocols were approved by the institutional animal ethics committee. Animals were obtained from the medical and surgical experimental research center of the institute. All rats were housed in polycarbonate cages in a room with controlled temperature (22 ± 2°C), humidity (50 ± 5%), and a 12 hour cycle of light and dark and were fed laboratory pellet chows and water was given ad libitum. The experiment was performed after a stabilization period in the laboratory for fifteen days. All the rats used in the following experiments were subject to the Guiding Principles for the Care and Use of Laboratory Animals and the Recommendations of the Declaration of Helsinki.
The evaluated untreated specimens from rat maxillas were obtained from a previously performed study (6). In this study, 28 male Spraque-Dawley rats (250-300 g) were randomized into four groups of seven each. Unilateral standardized closed fracture model was performed in fibulas of all rats. The NSAIDs: dexketoprofen trometamol; administered to group I, 0.98 mg/kg per half a day, meloxicam; administered to Group II, 0.2 mg/kg per day and diclofenac sodium; administered to Group III, 1mg/kg per day after performing the fibular fractures. No pharmacological agent was administered to the control group after performing the fibular fractures. The NSAIDs were applied to all groups for the first 10 days parenterally after the occurrence of the fractures in clinical dosages. Any procedure or treatment was not performed in rat alveolar bones. Maxillary alveolar bone was removed from the rats. The bone specimens were first immersed in a 10% formalin solution and the soft tissues separated from the bone the following day. Afterwards they were put into a 10% nitric acid solution for 2 days. The samples which decalcified were washed under the flowing water for 2 hours to remove acid residue. Each sample was divided to expose the union and routine tissue follow-up procedures were carried out. At the end; the paraffin embedded tissues were cut into slices 4 μm thick, stained with hematoxylin eosin and were observed under the light microscopy (Olympus CX41). The alveolar bones were evaluated for their spongious bone density, and the osteoclastic and osteoblastic densities were compared between the different experimental groups. Each parameter was classified separately. The ratio of spongious bone density to a total trabecular bone observed in cross section was evaluated (1, less than 10%; 2, between 10% and 20%; 3, more than 20%). Osteoblast density was determined through counting of the osteoblasts around the bone lamellae in the active-intense proliferation area (3× magnification) (1, 24 or fewer osteoblasts; 2, 25-34 osteoblasts; 3, 35 or more osteoblasts). Osteoclast activity was determined through counting of the osteoclasts around the bone trabeculae (1, average of 3 or fewer osteoclasts; 2, average of 4-6 osteoclasts; 3, average of 7 or more osteoclasts) (7).
Statistical Analysis
A computer program was used for the statistical analysis (SPSS, Windows, 11.5, Chicago, IL, USA.). Mean and standard deviation were calculated. The Levene’s test was used to analyze the homogeneity of the variances. If variances were not homogenous, the differences were analyzed using the Kruskal-Wallis variance analysis, bilateral comparisons were made by Mann- Whitney U test. The t test for paired samples was used when the variances distributed normally. Differences were considered statistically significant at p<0.05.
RESULTS
Statistical differences were observed (Table 1). We found that spongious bone densities were statistically significantly decreased in groups DEXT, MEL, and DIC compared to the control group (p < 0.05) (Figure 1). In contrast, osteoclastic densities were found to be statistically significantly higher in groups DEXT, MEL, and DIC than in the control group (p < 0.05) (Figure 2). The osteoblastic densities showed that there was a statistically significant decrease in groups MEL and DIC compared to the control group (p < 0.05) (Figure 3). Osteoblastic density in group DEXT was equal to the control group (p = 1.00) (Table 1). The DEXT group, compared to the MEL and DIC groups, seemed more consistent.
The Levene test was used to analyze the homogeneity of the variances. If variances were not homogenous, the differences were analyzed using the Kruskal-Wallis variance analysis, bilateral comparisons were made by Mann- Whitney U test. The t test for paired samples was used when the variances distributed normally. S.D.: Standard Deviation, * p<0.05 significant, ** p=1.00 equal, GROUP I: DEXT; GROUP II: MEL; GROUP III: DIC
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DISCUSSION
This study showed that systemically administrated NSAIDs for other purposes have the potential to affect the alveolar bone structure indirectly at the cellular level.
There are no studies about the indirect effects of NSAIDs on alveolar bone structure (osteoblastic/osteoclastic densities) during the use of drugs for any other purposes. In this study, as opposed to other studies, there has not been any process or stimulus performed to the alveolar bone. Nevertheless, NSAID use appears to affect the alveolar bone.
In the literature, which has generally benefited from studies in orthopedics, there are some animal studies about the effects of ketoprofen, indomethacin, ibuprofen, MEL, celecoxib, rofecoxib, and diclofenac on bone healing. Some of these studies showed that these drugs impaired bone healing, but other studies showed that they did not affect the healing processes (8-17). In addition, NSAIDs (a low dose of diclofenac) have been shown to prevent heterotopic ossification in rats (18).
Presently, there are a few studies devoted to this subject in dentistry. A small number of experimental studies have reported the effect of conventional NSAIDs on alveolar bone healing (19-23). In a histological study performed on the extraction sockets of dogs, it was reported that using aspirin cones presented a delay in alveolar bone formation in the first 2 weeks’ samples. But no effects were reported in the long term (4-8 weeks) (20). Yugoshi et al. (21) reported that treatment with diclofenac caused significant delay of bone neoformation in the alveolar repair process. Silva et al. (22) showed that DIC and MEL delayed bone graft repair and dexamethasone had no influence. Ketorolac and etoricoxib did not interfere with rat alveolar bone repair 2 weeks after tooth extraction (23). Teofilo et al. (19) suggested that a short-term treatment with nimesulide did not hinder alveolar bone healing in rats. Knop et al. (24) reported that diclofenac and dexamethasone halted bone resorption during the initial phase of orthodontic movement. As emphasized earlier in this study, there have not been any processes.
NSAIDs have an effect on the osteoblastic cell cycle and cell death. Some studies have shown that NSAIDs influence osteoblasts at therapeutic doses (25-27).
This study shows that osteoblastic density was significantly decreased in groups MEL and DIC compared to the control group. The most distinctive feature of our work in relation to other studies into the alveolar bone was that no process or stimulus was applied during the use of NSAIDs. This should be considered in the long-term use of NSAIDs, such as in ankylosing spondylitis patients (rheumatic diseases). We believe that the evaluation of indirect effects of the long-term use of NSAIDs on other tissue structures has potential for further scientific research.
