Influence of tip wear of piezoelectric ultrasonic scalers on root surface roughness at different working parameters. A profilometric and atomic force microscopy study.

Roughness on tooth surfaces is reported to facilitate the reestablishment of microbial dental plaque. Hence, the main goal of dental scaling is to remove bacterial plaque and obtain smoother tooth surfaces. This study was aimed to assess the influence of tip wear of ultrasonic scaler inserts on root surface roughness at different working parameters. Twenty piezoelectric ultrasonic scaler inserts (10 worn/10 new) were selected to examine the erosion ratio (ER) on the scaler tips and to assess the influence of tip wear on root surface roughness. Erosion on the tip surfaces was evaluated under atomic force microscopy (AFM). Root samples were prepared and instrumented by new (Group I) and worn (Group II) inserts at different working parameters. Roughness change (Rc) on root surfaces after instrumentation was examined under profilometer and compared between and within the groups. Statistically significant differences were found between the mean ERs of new and worn tips (P < 0.01). The results of this study showed that tip angulation and instrument power strongly influenced the Rc values on instrumented samples (P < 0.05). It was also revealed that tip wear influenced the Rc values on root surfaces especially at 45° tip angulation (P < 0.05). Therefore, tip wear should also be considered as much as the other parameters to minimize the surface roughness during ultrasonic treatment.

Diagnosis and treatment of mandibular extraoral sinus of periodontal origin in a 9-year-old boy: a case report.

Cutaneous sinus tract of dental origin is the commonest of the many types of sinus tracts that are formed on the face and neck. Cutaneous sinus tracts may originate from local chronic osteomyelitis (Garre's osteomyelitis). Although the etiological factor is usually periapical infection, they are seldom of periodontal origin. Conventional periapical and panoramic roentgenograms are generally insufficient for diagnosis and treatment planning of cutaneous sinus tracts of periodontal origin. In the present case, computed tomography was used for diagnosis, and osteomyelitis was managed by periodontal treatment.

Effects of nitric oxide synthase inhibition on intestinal damage in rats with experimental necrotizing enterocolitis.

In the inflamed intestinal mucosa of necrotizing enterocolitis (NEC), nitric oxide (NO) generated by inducible nitric oxide synthase (iNOS) may contribute to the pathogenesis of local intestinal damage. To study the importance of iNOS for the pathogenesis of NEC, the effects of selective (aminoguanidine, AG) and nonselective (L-nitroarginine methyl ester, L-NAME) iNOS inhibitors on intestinal morphologic changes were assessed in neonatal rats with experimental NEC. The neonatal rats were randomized into one of the five treatment groups. The control group consisted of rats that were breast-fed. The NEC group, consisting of neonates separated from their mothers, were gavaged with a special rodent formula to produce NEC. Rats in the sham, the AG, and the L-NAME groups were gavaged in a similar fashion to those in the NEC group; in addition, they were treated with 0.9 % saline, 10 mg/kg/day AG, and 10 mg/kg/day L-NAME, respectively. The rats were sacrificed on day 4, and the last 4 cm of terminal ileum was harvested for morphological studies and detection of nitrite and nitrate levels in tissue. The animals in the NEC and sham groups showed various degrees of intestinal inflammatory changes and increased tissue levels of nitrite and nitrate compared to those in the control group. Both AG and L-NAME treatment decreased the tissue levels of these nitrogen oxides, but the inflammatory changes of the intestine appeared to be attenuated only in the AG treated animals. L-NAME treatment did not improve the intestinal damage and increased mortality. These results may indicate that NO synthesized by iNOS plays a pathogenic role in formula-fed induced NEC and that inhibition of iNOS improves intestinal inflammatory damage.

The impact of oral feeding on the severity of acute pancreatitis.

BACKGROUND: In the management of acute pancreatitis, oral feeding is prohibited and either enteral or parenteral feeding is commenced for the patients in an effort to not increase the secretion of the pancreatic enzymes. PURPOSE: This study was undertaken in an attempt to determine the impact of oral feeding on the severity of acute pancreatitis and to compare this impact with that of parenteral feeding. MATERIALS AND METHODS: Twenty-four female Sprague-Dawley rats were divided into two groups. In both groups, acute pancreatitis was induced by ligation of the main biliopancreatic duct. The rats in group I were fed orally and the rats in group II were fed parenterally. The rats were sacrificed at 48 hours, and blood samples were obtained from the heart upon exposure of the abdominal and thoracic cavities. The pancreas and the left lung were removed for histopathological examination. The levels of lactic dehydrogenase (LDH), serum glutamic oxaloacetic transaminase (SGOT), glucose, calcium and blood urea nitrogen, base deficit, partial oxygen pressure, leukocyte count, and hematocrit level among Ranson criteria and the level of amylase were measured. The pancreas and the lung were examined under a light microscope. RESULTS: The levels of LDH, SGOT, and calcium for the rats in group I were significantly higher when compared with the rats in group II (P <0.05). Similarly, the levels of amylase for the rats in group I were found to be higher when compared with the rats in group II, but the difference was not significant. Inflammatory changes observed in the pancreas were less severe whereas inflammatory changes observed in the lung were more severe for the rats in group I when compared with the rats in group II. CONCLUSION: The blood levels of the enzymes were adversely affected for the rats fed orally. In contrast, inflammatory changes observed in the pancreas were more severe for the rats fed parenterally. The study suggests that certain hormones released from the duodenum upon stimulation by oral nutrient intake lessens the severity of pancreatitis through protective effects on the pancreas, whereas the elevated levels of the enzymes cause endothelial damage resulting in destruction in distant organs such as the lung.

Nitric oxide synthase inhibition prevents intestinal damage in gastroschisis: a morphological evaluation in chick embryos.

PURPOSE: Increased small bowel nitric oxide (NO) synthase activity accused for postnatal intestinal dysmotility in gastroschisis. The purpose of this study is to evaluate the effect of prenatal NO synthase inhibition on intestinal damage in gastroschisis. METHODS: Sixteen-day-old fertilized chick eggs were divided into 4 groups. In the control group, the allantoic and amniotic membranes were opened to create a common cavity. In the gastroschisis group, a defect in the abdominal wall was made, and intestinal loops were exteriorized. In the gastroschisis pretreated with L-NAME group, gastroschisis was created, and L-NAME was administered into the amnioallantoic cavity for 4 days. In the gastroschisis sham pretreated group, after the same surgical procedure as the previous group, same amount of saline was given beside L-NAME. At the end of 20th day of incubation, intestinal morphological changes were investigated macroscopically and microscopically. RESULTS: Macroscopic changes such as shortening, thickening, and fibrous adhesions were found in the exteriorized bowels of the just gastroschisis group and the gastroschisis pretreated saline group. However, there was only mild thickening in the gastroschisis pretreated with L-NAME group. Microscopically, compared with the gastroschisis group, serosal thickness, muscular thickness, and bowel wall thickness were found to be significantly lower in the gastroschisis pretreated with L-NAME group (128.0 +/- 19.3 microm and 239.5 +/- 3.0 microm v 57.0 +/- 8.2 microm and 145.0 +/- 9.7 microm). CONCLUSION: It is possible to decrease intrauterine intestinal morphological changes in gastroschisis by inhibiting NO synthase.

Testicular changes in newborn rats exposed to phototherapy.

In this study we investigated the long-term effects of 72-h continuous phototherapy on the reproductive system of newborn rats. The animals' weight, fertilization rates, and number of newborn and histopathological changes in the gonads in a normal group not exposed to phototherapy and in the test animals were compared. At the age of 24 weeks there were no significant differences between the two groups, apart from the histology of the testicles of the male rats who were exposed to the phototherapy. The study group showed a significantly reduced diameter of the seminiferous tubules when compared to the controls (P < 0.001). It can be postulated that phototherapy may cause histological degenerative changes in the structure of the rat's testes, even though there were no changes in fertilization rates. Further studies are necessary to reveal the effects of phototherapy on humans and to determine the effects, if any, on fertility.

Treatment of intestinal reperfusion injury using antioxidative agents.

BACKGROUND/PURPOSE: A number of antioxidants are present in human tissues, which comprise the secondary defence system against the oxygen-free radicals and oxidative stress. Therefore, this study was undertaken in an animal model to investigate the effects of antioxidants such as vitamin E, vitamin C, methyl prednisolone, and mannitol, on the treatment of intestinal reperfusion injury when given during ischemia. METHODS: The study was performed on six groups of animals, each composed of six rabbits: Group I, mesenteric ischemia group; group R, ischemia-reperfusion group; group E, ischemia-reperfusion plus Vitamin E treatment; group C, ischemia-reperfusion plus vitamin C treatment; group CS, ischemia-reperfusion plus corticosteroid treatment; and Group M, ischemia-reperfusion plus mannitol treatment. Malondialdehyde (MDA) and glutathione (GSH) levels of the intestinal mucosa were assayed to reflect the free radical formation. RESULTS: Mucosal injury scores in the M and C groups were significantly lower than the R group (P< .01 and P< .01, respectively), and in the E and CS groups, mucosal injury scores were not significantly different from R group. MDA levels in the M and C groups were significantly lower than the R group (P < .01 and P < .01, respectively). GSH levels in the E, C, and M groups, were significantly higher than R group (P < .01, P < .05, and P < .01, respectively). CONCLUSION: The results of this study showed that antioxidant drugs, such as vitamin C and mannitol, may play a role in attenuating reperfusion injury of the gut demonstrated by depression of tissue MDA levels and by elevation of tissue GSH levels.

Ultrasound-guided percutaneous drainage in the treatment of children with hepatic hydatid disease.

The present study was designed to establish the safety and efficacy of ultrasound-guided percutaneous drainage in the treatment of hepatic hydatid cysts in children. A total of 14 cysts in eight patients were drained under aseptic conditions and continuous ultrasound guidance. An 18-G needle was used for puncture and silver nitrate solution as the scolecoidal agent. All procedures were successful. During follow-up, repeated ultrasound examinations revealed a progressive decrease in cyst size and an alteration in the cyst echopattern. None of the patients had a rise in hydatid antibody titer. There were no immediate or late complications. We conclude that the safety and efficacy of ultrasound-guided percutaneous drainage are satisfactory for the treatment of hepatic hydatid cysts in children.