Evaluation of Histological Impacts of Three Types of Orthodontic Fixed Retainers on Periodontium of Rabbits

ABSTRACT Statement of the Problem: Fixed retainers were developed to maintain incisor alignments after orthodontic treatments. Although the effects of fixed retainers on periodontal health are clinically studied, no studies have still evaluated the histological changes in the periodontium after the placement of thefixed retainers. Purpose: The aim of this study was to evaluate the effects of customised retainers on periodontium histologically. Materials and Method: Forty pairs of maxillary and mandibular central incisors of twenty rabbits were randomly divided into four equal groups: The first group was considered as the control and in the second group, Fiber Reinforced Composite (FRC), in the third group, 0.014 inch stainless steel (SS) wire and in the fourth group, 0.175 inch multistrand stainless steel (MSS) wire were bonded on the labial surfaces of the incisors. After sixty days; animals' periodontium were evaluated histologically. Results: The number of bone resorption lacuna in the control group was significantly less than FRC and 0.014 SS groups. The periodontal vessel count and their diameter in the control group was significantly lower than the other groups. The pulp vessel count and their diameter in controls were significantly more than the 0.014 SS and the 0.175 MSS groups. Conclusion: Findings of this study suggest that FRC fixed retainer might cause detrimental effects on the periodontal ligaments and supporting bone and the 0.014-inch and 0.175-inch fixed retainers can cause hyalinization and possibly the necrosis of the pulp

Experimental induction of left abomasal displacement: a new educational technique

Summary The purpose of this study was to induce abomasal displacement to the left, and to let the undergraduate and post graduate students get used to the ping sounds of abomasum and other clinical manifestations. The procedure was carried out on eight young bulls, they were sedated and a 2 m flexible tube was inserted through the nasal canal into the rumen. By laparo-rumenotomy, 20 cm of the tube was inserted into the abomasums through the omaso-abomasal groove. The rumen wall and abdominal wall were apposed routinely. The animal was casted on its right side on the floor. The abomasum was inflated through the external end of the tube which was tied to bull's horn base. Then the animal was allowed to stand on its feet. The gas filled abomasum was mobilized to the left flank between the body wall and the rumen. The left abomasal displacement was confirmed by ping and ultrasonography. Experimental induction of left abomasal displacement by inflating the abomasum using a nasal abomasal tube following rumenotomy is a safe and suitable technique for educational and research purposes

Cytokeratin: a Shortcut to Diagnose Spindle Cell Carcinoma

A relatively rare subtype of squamous cell carcinoma (SCC) is spindle cell carcinoma (SPCC). It is composed of epithelium-derived spindle cells arranged in sheets with mesenchymal properties and small, hard-ly detectable regions of SCC, challenging its definite diagnosis. We encountered five cases of SPCC. In case one, chronic inflammation and subepithelial blister with leukoplakia was found 5 years before our examination. And later, exophytic features, keratotic papules and scar with elevated margins was seen on lateral border of the tongue. In case two, three and four, an abnormal soft tissue elevations were examined, and in the fifth case we examined the soft and bony speci-men from the posterior aspect of maxillary ridge. We evaluated all of them histologically and immunohistochemically for cytokeratin to reach final diagnosis

Increased Microleakage of Amalgam Restorations after Exposure to 2.4 Ghz Radiofrequency Electromagnetic Fields from Common Wi-Fi Routers

Statement of Problem: Previous studies have shown that exposure of dental amalgam fillings to MRI and mobile phones can increase microleakage of amalgam restorations. Objectives: The aim of this study was to evaluate the effects of exposure to radiofrequency radiation emitted from indoor Wi-Fi access devices on microleakage of amalgam restorations. Materials and Methods: Standard class V cavities were prepared on the buccal surfaces of 69 extracted human premolar teeth. The samples were divided into two exposure groups and one non-exposed control group of 23 teeth each. The specimens in the experimental groups were exposed to a radiofrequency (RF) radiation emitted from a commercial 2.4 GHz Wi Fi router. The distance between the Wi-Fi router and samples was 30 cm and the router was exchanging data with a laptop computer that was placed 20 m away from the router. Teeth samples in the first exposure group (group A) were exposed to RF for 3 days while the second exposure group (group B) was exposed for 6 days. Then the teeth were sectioned and scored for microleakage under a stereomicroscope. Results: The score of microleakage was significantly higher in the exposure group A compared to that of the control group. However, the score of microleakage was not significantly different between the exposure group B and control group. Furthermore, the scores of microleakage was signifi-cantly higher in the exposure group A than that of the exposure group B. Conclusions: Exposure of patients with amalgam restorations to radiofre-quency waves emitted from commercial Wi-Fi routers can lead to in-creased microleakage of amalgam restorations