Hyaluronic acid (HA) is one of the essential components of extracellular matrix, which plays a predominant role in tissue morphogenesis, cell migration, differentiation, and adhesion. Bone allografts are frequently used to repair and reconstruct bone defects. In this study, two cavities of 3 mm diameter and depth have been created in the right tibia of 30 mature rabbits in accordance with the principles of general surgery. One of the cavities in the tibia is filled with HA and bone graft and the other is filled with only spongiosal bone graft, for the purpose of control. On the 20th, 30th, and 40th days, rabbits have been sacrificed in equal numbers and defective regions have been extracted. The Kruskal-Wallis test was applied to the data obtained in the result of histopathologic survey of specimens. In conclusion, the cavities that have been filled with HA and bone graft have shown higher scores than the control group during every period of the study.

This study aimed to investigate the effects of heavy orthopaedic forces, produced by rapid maxillary expansion, on pulpal tissue of pre-molar teeth. Teeth extracted as part of an orthodontic treatment plan, an average of 3 months, 6 months and 18 months after rapid maxillary expansion, were analysed using histopathological techniques. Control teeth were extracted, for orthodontic reasons, before any force treatment. Non-parametric tests were used to compare the results from the three treatment groups and one control group. Vessel diameter, haemorrhage, congestion and inflammatory cell infiltration varied between groups, and the differences between the control and 3-month groups, and the 3-month and 18-month groups were most significant. In conclusion, orthopaedic forces exerted by rapid maxillary expansion caused reversible vascular changes in pulpal tissue of upper pre-molar teeth.

Long-term systemic use of corticosteroids causes osteoporosis and increased risk of fracture. However, the effect of short-term use of corticosteroids on bone healing is not well defined. The aim of the present study was to test the influence of short-term systemic corticosteroid therapy on bone healing. Standardized bone defects (2 mm diameter) were formed in the middle of the femur in 40 male rats. Rats were divided into two groups; control group (n = 20) and prednisone-treated group (n = 20). Subcutaneous injection of either sterile normal saline (control) or 0.020 mg kg(-1) dose of prednisone was administered just before surgery and thereafter daily for 3 days. Histopathological cross sections were taken 1, 2, 3 and 4 weeks after surgery. There was no statistically significant difference between the prednisone group and the control group. No inhibitory effects were seen following short-term corticosteroid treatment.

In this study, the effects of guided bone regeneration (GBR) on the healing of bone defects were evaluated. Resorbable membranes were placed in experimentally formed cavities in the right posterior tibia of 30 rabbits. Decalcified histological sections were evaluated using optical microscopy at 10, 20, and 30 days after GBR. Osteocondrial bone union, active bone formation and spongiosal bone formation values of the GBR group are higher than the control group. It was found that GBR technique had a positive and accelerating influence in all phases of bone healing.

The effect of bone chips dehydrated with solvent on the healing of bone defects was evaluated. Solvent-dehydrated spongiose bone chips were placed in experimentally formed cavities in the right back tibia of rabbits. After 10, 20 and 30 days, histopathological cross-sections from the bone grafts were examined microscopically for bone healing and formation of spongiose bone, cortex and bone marrow. Spongiose bone chips had a positive and accelerating influence on the healing of bone defects in the 10-day period after transplantation, but no significant differences were observed between the treated and control groups 20 and 30 days after transplantation.