Background and Objectives: This study aimed to histologically evaluate the effects of local melatonin application at different doses on bone fracture healing. Materials and Methods: Thirty rats were divided into three groups, with ten rats in each group. In the control group (n = 10), a fracture line was created in the tibial bones, and fracture osteosynthesis was performed without any additional procedure. In the local melatonin dose 1 (MLT D-1) group (n = 10), a fracture line was created in the tibial bones, and 1.2 mg of lyophilized powder melatonin was applied locally before fracture osteosynthesis. In the local melatonin dose 2 (MLT D-2) group (n = 10), a fracture line was created in the tibial bones, and 3 mg of lyophilized powder melatonin was applied locally before fracture osteosynthesis. After a 12-week healing period, all subjects were sacrificed, and tibial bones were collected for histomorphometric analysis. Results: The percentage of bone formation was significantly higher in the MLT D-1 and MLT D-2 groups than in the control group. There was no statistically significant difference between the MLT D-1 and MLT D-2 groups. Conclusions: In conclusion, the study demonstrated that local melatonin application supports bone fracture by increasing bone formation, although different doses of melatonin did not lead to significant variations in fracture healing.

This study aimed to investigate the effect of local melatonin application on bone healing in critical size defects created in rat tibias. 30 Spraque Dawley rats selected for the experimental setup were divided into three groups, each with 10 rats. In the control– defect group (n=10), only defects were created in the tibia bones of the rats, while 1.2 mg and 3 mg melatonin were applied locally to the defect–melatonin dose 1 (n=10) and defect melatonin dose 2 (n=10) groups, respectively. At the end of the experiment the subjects in all the groups were euthanized after an 8-week healing period and defect healing was calculated with histological bone healing percentage. The Shapiro–Wilk test and the Kolmogorov–Smirnov test were used to evaluate the conformity of the data to a normal distribution. One–way ANOVA was used to determine whether there was a difference between the groups due to the normal distribution of the data, and Tukey’s honestly significant difference (HSD) test was used in pairwise comparisons to determine from which group the difference originated. The healing rate in the defect melatonin dose 2 group was calculated as 53.2 ± 7.38% and the healing rate in the control group was calculated as 44 ± 6.38%, which was a significant increase (P=0.008); however, when the difference between the defect melatonin dose 1 group (53 ± 7.1%) and the defect melatonin dose 2 group (53. 2± 7.38%) was evaluated statistically, no significant difference was found.The bone healing percentage in the groups where local melatonin was applied was found to be statistically significantly higher compared to the control group (P0.05). Within the limits of this study, it can be said that local melatonin application applied at two different doses had a positive effect on bone healing, however, no difference was observed between the applied local melatonin doses in terms of bone healing.

The aim of this study is to investigate the osseointegration levels of implants with different surfaces locally applied with enamel matrix protein by biomechanical methods. Thirty adult female Spraque Dawley rats weighing 300–350 g were included in the study as subjects. The rats were divided into 3 groups with 10 rats in each group: Machined Surface Group (n = 10), Sandblasted Large Acid Grid (SLA) Surface Group (n = 10) and Resorbable Blasting Material (RBM) Surface Group (n = 10). Titanium implants were surgically placed in the right tibias of the rats with sterile physiological serum cooling. Immediately before the implants were placed, local enamel matrix protein was applied to the prepared sockets and then the implants were placed. The rats were euthanized after waiting for osseointegration for four weeks and the implants were taken with the surrounding bone tissues after the soft tissues were removed. The bone–implant contact of all implants was analyzed by biomechanical method and recorded in Newton·cm-1 (N·cm-1). When the obtained biomechanical data were examined, the average bone–implant contact value was found to be 2.24 ± 0.67 (N·cm-1) in machined surface implants, 4.5 ± 1.36 (N·cm-1) in SLA surface implants and 3.24 ± 0.94 (N·cm-1) in RBM surface implants. A statistically difference was detected between machined surface implants and SLA surface implants (P<0.05; P=0.02). It can be stated that local enamel matrix protein application may increase bone–implant connection in SLA surface implants.

In this study, the histopathological diagnosis and treatment of an intermuscular lipoma were reported in a dog. In the clinical inspection, there was a large mass in the caudal of the left femur and that the animal had difficulty in moving. On palpation, the mass was solid and painful. A decision was made to totally extirpate the mass, which was suspected to be a tumor. A wide skin incision was made from the caudal part of the left femur; the mass was separated from the surrounding tissues by blunt dissection and extirpated. Histopathological examination revealed that the mass was an intermuscular lipoma. In the postoperative period, the patient recovered completely and returned to its normal life.

Osseointegration refers to the process where an implant firmly and functionally bonds with the bone, establishing a stable union capable of bearing loads without any relative movement between the implant and the surrounding bone tissue. Post- surgery infections that may develop in the surgical area can negatively affect osseointegration, putting the success of the implant at risk. The objective of this research was to evaluate the impact of antibiotics derived from levofloxacin and cephalexin on the osseointegration of implants in the tibias of rats. A total of 21 female Sprague Dawley rats were utilized, randomly divided into three equal groups of seven rats each. Titanium implants measuring 2.5 mm in diameter and 4 mm in length were inserted into cavities created in the corticocancellous bone of the metaphyseal region of the right tibias of all animals. In the implant control group (n=7), no additional procedures were performed throughout the two- week experimental period. Subjects in the implant levofloxacin group (n=7) received subcutaneous injections of levofloxacin at a dose of 25 mg/kg, administered three times weekly for two weeks. Similarly, rats in the implant cephalexin group (n=7) were given subcutaneous injections of cephalexin at a dosage of 20 mg/kg, three times per week for two weeks. Two weeks after the operation, the implant samples in the tibias of the rats were subjected to biomechanical analysis using a digital torque device in order to evaluate the osseointegration process. As a result, it was observed that levofloxacin and cephalexin-derived antibiotics had a negative effect on implant osseointegration in the tibias of rats.

The aim of this study is to histopathologically examine the effect of intermittent fasting, which has been followed with interest by researchers recently, on the healing of bone defects created in rat tibias. Sixteen Sprague–Dawley rats were included in this experimental study. For this purpose, the rats were divided into two groups: a defect control group (n = 8) and a defect + fasting group (n = 8). In the defect groups, a 4 mm diameter and depth defect was created in the corticocancellous bone of the metaphyseal tibia. Intermittent fasting was applied to the fasting groups three days a week for eight weeks. All animals were sacrificed at the end of the process, and the tibias were decalcified and examined histopathologically, with new bone formation and callus were assessed. Data were analyzed statistically. Student’s t–test was used for statistical analysis. The mean longitudinal defect size value for the control group was 1675.43, while that of the fasting group was 1594.29. The mean vertical defect size value for the control group was 576.86, while that of the fasting group was 528. And the mean callus size value for the control group was 145, while that of the fasting group was 154.14. Both bone formation and callus values were numerically higher in the fasting group compared to the control group. However, these differences were not statistically significant (P>0.05). Based on the limited results of this study, although intermittent fasting may have a potential biological effect in supporting bone healing, no statistically significant difference was found in this study.