The effects of low-level laser therapy on the healing of bone defects in streptozotocin-induced diabetic rats: A histological and morphometric evaluation.

BACKGROUND: The aim of the present study was to evaluate the effects of low-level laser therapy (LLLT) on the healing of bone defects in rats with streptozotocin (STZ)-induced DM. METHODS: 28 male Sprague-Dawley rats were used in this study. 14 animals received a single dose of STZ intraperitoneally (65 mg/kg) to induce Type I DM, whereas others were injected only with sterile saline solution. Four weeks later, standard bone defects were created in the tibiae of rats. Surgical wounds in one group from each of the diabetic and non-diabetic animals were irradiated with diode laser for every other day for 4 weeks and they were described as DM + LLLT and CONT + LLLT groups, respectively. Remaining two groups received no laser treatment. New bone formation, osteoblast and blood vessel counts were calculated in histologic sections. RESULTS: DM group had significantly smaller bone area and lower blood vessel count when compared to DM + LLLT, CONT and CONT + LLLT groups (p < 0.05 for each). CONT and CONT + LLLT groups had significantly larger bone area than DM + LLLT group (p < 0.05 for both). CONCLUSIONS: LLLT application promoted vascularization and new bone formation in animals with DM to a limited extent, since it was unable to support the healing process up to the level of non-diabetic animals.

The effects of supplemental melatonin administration on the healing of bone defects in streptozotocin-induced diabetic rats.

OBJECTIVE: The aim of this study was to investigate histologic and biochemical effects of supplemental melatonin administration on bone healing and antioxidant defense mechanism in diabetic rats. MATERIAL AND METHODS: Eighty-six Sprague-Dawley male rats were used in this study. Diabetes mellitus was induced by intraperitoneal (i.p.) administration of 65 mg/kg streptozotocin (STZ). Surgical bone defects were prepared in the tibia of each animal. Diabetic animals and those in control groups were treated either with daily melatonin (250 µg/animal/day/i.p.) diluted in ethanol, only ethanol, or sterile saline solution. Rats were humanely killed at the 10th and 30th postoperative days. Plasma levels of Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA), and Superoxide Dismutase (SOD) were measured. The number of osteoblasts, blood vessels and the area of new mineralized tissue formation were calculated in histologic sections. RESULTS: At the 10th day, DM+MEL (rats receiving both STZ and melatonin) group had significantly higher number of osteoblasts and blood vessels as well as larger new mineralized tissue surfaces (p<0.05 for each) when compared with DM group. At the 30th day, DM group treated with melatonin had significantly lower levels of AOPP and MDA than those of DM group (p<0.05). CONCLUSION: Melatonin administration in STZ induced diabetic rats reduced oxidative stress related biomarkers and showed beneficial effects on bone healing at short term.

The effects of supplemental melatonin administration on the healing of bone defects in streptozotocin-induced diabetic rats

ABSTRACT Diabetes mellitus (DM) causes an increased production of free radicals that can impair bone healing. Melatonin is a hormone secreted mainly by the pineal gland, which participates in the neutralization process of free radicals. Objective The aim of this study was to investigate histologic and biochemical effects of supplemental melatonin administration on bone healing and antioxidant defense mechanism in diabetic rats. Material and Methods Eighty-six Sprague-Dawley male rats were used in this study. Diabetes mellitus was induced by intraperitoneal (i.p.) administration of 65 mg/kg streptozotocin (STZ). Surgical bone defects were prepared in the tibia of each animal. Diabetic animals and those in control groups were treated either with daily melatonin (250 μg/animal/day/i.p.) diluted in ethanol, only ethanol, or sterile saline solution. Rats were humanely killed at the 10th and 30th postoperative days. Plasma levels of Advanced Oxidation Protein Products (AOPP), Malondialdehyde (MDA), and Superoxide Dismutase (SOD) were measured. The number of osteoblasts, blood vessels and the area of new mineralized tissue formation were calculated in histologic sections. Results At the 10th day, DM+MEL (rats receiving both STZ and melatonin) group had significantly higher number of osteoblasts and blood vessels as well as larger new mineralized tissue surfaces (p<0.05 for each) when compared with DM group. At the 30th day, DM group treated with melatonin had significantly lower levels of AOPP and MDA than those of DM group (p<0.05). Conclusion Melatonin administration in STZ induced diabetic rats reduced oxidative stress related biomarkers and showed beneficial effects on bone healing at short term.

Assessment of dental fear and anxiety levels in eating disorder patients undergoing minor oral surgery.

PURPOSE: The aim of the present study was to evaluate the levels of dental fear and anxiety in women with eating disorders (EDs) scheduled for oral surgery. PATIENTS AND METHODS: A total of 61 patients with EDs, an identical number of age-, gender-, and education-matched healthy controls, and 2 consecutive, randomly selected, clinical and nonclinical samples each consisting of 220 female subjects were included in the present study. The participants completed the demographic and clinical forms, as well as the modified dental anxiety scale (MDAS) and dental fear survey (DFS) before the surgical procedure. RESULTS: The mean scores of the MDAS and DFS for the study population correlated negatively with age and positively with a previous unpleasant experience related to dentistry (P < .01 for both). Patients with EDs had significantly greater mean scores on the MDAS than the clinical and nonclinical groups (P < .05 for both). Their mean scores on the DFS were significantly greater than those for the nonclinical participants (P < .05). A significant difference was found in the DFS subscale "fear of specific situations and stimuli" compared with the healthy matched controls and clinical and nonclinical subjects (P < .05 for all). CONCLUSION: The results of our study have shown that patients with EDs can be more sensitive to the auditory, visual, and contact stimuli of the oral surgery procedures under local anesthesia. They also had greater levels of dental fear and anxiety than routine clinical patients and randomly selected subjects from a nonclinical environment.

The influence of hyperbaric oxygen treatment on the healing of experimental defects filled with different bone graft substitutes.

To assess potential effects of hyperbaric oxygen (HBOT) on artificial bone grafts, ß - Tricalcium phosphate (ß-TCP) and calcium phosphate coated bovine bone (CPCBB) substitutes were applied to standard bone defects in rat tibiae. The control defects were left empty. Half of the animals received 60 minutes of 2.4 atmosphere absolute (ATA) of HBOT. Rats were sacrificed at one, two and four weeks. Bone healing was assessed histologically and histomorphometrically using light microscopy. The periosteum over the bone defects was examined ultrastructurally. Cardiac blood was collected to determine the serum osteocalcin levels. The HBOT increased new bone formation in the unfilled controls and ß-TCP groups and significantly decreased cartilage matrix and fibrous tissue formations in all groups. Active osteoblasts and highly organized collagen fibrils were prominent in the periosteum of ß-TCP and control groups. Serum osteocalcin levels also increased with HBOT. The healing of defects filled with CPCBB was similar to the controls and it did not respond to HBOT. These findings suggested that the HBOT had beneficial effects on the healing of unfilled bone defects and those filled with ß-TCP bone substitute but not with CPCBB, indicating a material-specific influence pattern of HBOT.

Prevention of liquid-diet-induced damages on submandibular glands by selenium supplementation in rats.

This study was designed to explore the protective effects of selenium on submandibular glands of rats that were maintained on liquid diet. The animals kept on liquid diet for 10 days following 20 days of solid diet, had severe degeneration on both acinar and ductal cells: pycnotic nuclei, enlarged granular endoplasmic reticulum, swollen mitochondria with separated cristae, reduction of secretory granules and abundant lipid droplets were observed. Body and gland weights of these animals were found to decrease significantly compared to those of control group given solid diet for 30 days. The animals that were fed 20 days with solid diet + 10 days liquid diet and also given selenium 0.4 mg/kg for 30 days, did not have any remarkable sign of degeneration on submandibular glands, and their gland weights significantly increased when compared to the animals fed with liquid diet without selenium supplementation. Submandibular glands of the group that was maintained on solid diet for 30 days and supplemented with selenium in drinking water were found to be normal. They showed consistent gain in both body and gland weights almost equal to that of control group. As a result, we assume that adding selenium in liquid diet can prevent the detrimental effects of liquid diet consumption on submandibular glands.