Unusual Case of External Juxta Coronal Odontoma.

Odontomas are benign tumors of jaws with mixed tissue, which are the result of proliferation of odontogenic epithelium and mesenchymal cells. They occur almost centrally and seldom peripherally. There is no report of such a lesion externally while attaching a tooth crown. In this case, we present a lesion on the buccal surface of the right maxillary central incisor crown, which is misconstrued with a dental overgrowth. Such cases may confuse diagnosis during clinical examination. Radiographically, such odontomas may be mistaken for various other lesions. Ultimate diagnosis should be relied upon microscopic evaluation and histopathological results.

Effects of in vitro low oxygen tension preconditioning of buccal fat pad stem cells on in Vivo articular cartilage tissue repair.

AIMS: Progenitor cells-based regenerative strategy has shown promise to repair cartilage, an avascular tissue in which cells experience hypoxia. Hypoxia is known to improve the early chondrogenic differentiation of stem cells. Therefore, this study aimed to determine whether hypoxia preconditioning could be used to enhance the regenerative potential of the combination of buccal fat pad stem cells (BFPSCs) and bilayer chitosan-based hydrogel scaffold for articular cartilage repair. MATERIALS AND METHODS: Human BFPSCs were seeded on the bilayer chitosan-based hydrogel scaffolds in the culture medium. The viability and proliferation of cells on the scaffolds were monitored using scanning electron microscopy (SEM), MTT assay, and DAPI staining. Hypoxia preconditioned BFPSCs-seeded scaffolds were transplanted into rabbit articular cartilage knee defects for 12 weeks. The newly formed tissue was evaluated by cartilage-specific immunohistological analysis and histological staining. KEY FINDINGS: It was found that the chondrogenic differentiation and osteochondral conjunction in articular cartilage defect via BFPSCs-seeded bilayer scaffolds was enhanced by hypoxic preconditioning compared to a normoxic environment. SIGNIFICANCE: Based on our study, the integrity with subchondral bone in osteochondral defect was enhanced by BFPSCs on bilayer scaffold. Thus, this study provides evidence on the design of preconditioned cell-seeded bilayer hydrogels for articular cartilage regeneration.

Donor nerve graft assessment for covering thumb nerve defects: a cadaveric study.

BACKGROUND: Even though several studies reported donor autologous nerve grafts for digital nerve defects, there is no report in the literature regarding acceptable graft for thumb nerves. The purpose of this study is to provide guidelines for autologous nerve graft selection by detecting similarities between thumb nerve zones and donor nerve with regard to the number of fascicles and cross-sectional area. MATERIALS AND METHODS: Five cadavers were used in this study. An anatomical zoning system was defined for thumb nerves (zones 1, 2, 3). Sural nerve (SN), medial antebrachial cutaneous nerve (MABCN), lateral antebrachial cutaneous nerve (LABCN), posterior interosseous nerve (PIN), and anterior interosseous nerve (AIN) were selected as donor nerve grafts. The number of fascicles and surface area (mm2) was defined. RESULTS: The mean of the fascicle number in zone 1, zone 2, zone 3, AIN, PIN, LABCN, MABCN, and SN were 3.8, 4.7, 6.1, 2.2, 1.8, 4.5, 3.1, and 6.4, respectively. The mean of the surface area in zone 1, zone 2, zone 3, AIN, PIN, LABCN, MABCN, and SN were 2.19, 6.26, 4.04, 1.58, 0.71, 5.00, 3.01, and 8.06, respectively. CONCLUSIONS: LABCN is the best choice for all zones that has fascicular matching with all three zones of thumb nerves and caliber matching with zones 2 and 3. In zone 1, the best nerve graft is MABCN which has both suitable caliber and fascicle count.

Humeral fracture treatment in pigeons by bone pins made from ovine and canine bones.

The tubular, pneumatic long bones of the bird present unique challenges in veterinary orthopedics. Various traditional and innovative forms of fracture fixation have been applied in bird orthopedic. The purpose of this study was to compare the applicability of the stainless steel intra-medullary pin with the pins made from ovine and canine long bones. Ovine and canine long bones were used to prepare pins in appropriate size and dimension. The pins were treated chemically, hydrated, dried, packaged and sterilized by ethylene oxide. Forty domestic male pigeons were divided into four equal groups. Pigeons were anesthetized by combination of xylazine and ketamine. Humeral bones were cut by a diamond disc burr. In the first group the fractured bones were not treated and was regarded as control group. In the second group stainless steel pins were inserted into the humeral medulla of pigeons; and in the third and fourth groups, prepared pins from ovine and canine long bones were inserted into the medulla, respectively. The operated wing was bandaged to the body and stabilized. Post-operative care included: clinical assessment of surgical wound, wing holding and flight assessment. The flight behavioral assessment and radiographic studies were carried out every two weeks for 32 weeks. After 32 weeks the pigeons of the first group were not able to fly, in the second group pigeons had imbalance in flight; and in the third and fourth groups the pigeons were able to fly with no problem. Radiographic study showed no significant differences between groups 2, 3 and 4 but there was a significant difference between group 1 and other three groups. None of the bone pins were rejected; all were absorbed in later stages in large quantities. The IM pins made from long bones of sheep and dog pins can be considered as an appropriate and alternative internal fixation technique, because they are very firm, strong, provide very good internal fixation for bone alignment, showing no tissue sensitivity, no rejection and therefore not necessity to be removed. While the stainless steel IM pin creates imbalance in flight and they have to be removed after bone union is completed, which needs another surgical intervention and stress.

Ultrastructural and Chemical Composition of Dentin and Enamel in Lab Animals.

STATEMENT OF THE PROBLEM: Human tooth is clinically the most appropriate material that can be used for in-vitro dental research. However, there are limitations and drawbacks for using human teeth. Therefore, alternatives to samples of human teeth for dental studies are necessary. PURPOSE: This study purposed to evaluate and compare the microstructure and chemical composition of enamel and dentin of teeth in some lab animals. MATERIALS AND METHOD: In this experimental study, teeth of mouse, rabbit, guinea pig, dog, cat, and sheep were used. Scanning electron microscope observations and X-ray diffraction analysis were performed on samples. RESULTS: This study revealed resemblance in general structure of dentin and enamel between mentioned animals and human. The minimum mean of dentinal tubules diameter is found in guinea pig (0.5µ), while the highest is in cat (1.5µ). Also the lowest and the highest mean intertubular distance was measured respectively in guinea pig (3µ) and sheep (4.8µ) and the maximum and minimum mean diameter of rods was measured in rabbit (6.6µ) and guinea pig (1.5µ), respectively. CONCLUSION: The recorded details and the measured values indicate great resemblance between dog and human dentin and enamel. Cat is in the second place for dentinal studies; sheep and guinea pig have the least resemblance to human within the scope of the reviewed criteria.

Simvastatin vs. L-Carnitine: An experimental study on optimizing nerve repair.

AIM: Complicity and slow rate of axons regeneration necessitates microsurgery that adjuvant therapy can help it. Improving nerve metabolic capacity and response to neural growth factors are positive effects of simvastatin and L-carnitine. To decrease neuronal loss after axotomy and improve neuronal regeneration, this study was designed to assay effects of these agents on nerve repair. MATERIAL AND METHODS: Left sciatic nerve of 70 female rats were cut and repaired under aseptic microsurgery. Based on medications and treatment period, seven groups were formed. CONTROL: no medication. SIM1W: one week daily oral simvastatin. LC1W: one week daily oral L-carnitine. Plb1W: one week daily oral placebo. SIM1M: one month daily oral simvastatin. LC1M: one month daily oral L-carnitine. Plb1M: one month daily oral placebo. Following 90 days, behavioral assessments and then histopathology were done. RESULTS: Mean reflex time of withdrawal reflex latency and toe out angle in all experimented groups increased than normal. Long-term drug-medication significantly improved toe out angle. In long-term drug-medication, inflammation and neural bundle differentiation were significantly lower and higher, respectively. Vascular index showed reduction but number of myelinated nerve fibers had rises in drug-medicated groups compared to control and placebo groups. No obvious differences were detected in myeline diameter. CONCLUSION: Both Simvastatin and L-carnitine can accelerate and improve the process of nerve regeneration in a long enough treatment period. The regulatory influence of these exogenous neurotrophic drugs may be essential to optimize regeneration of nerve fibers; so can broaden horizons for novel therapeutic modalities to decrease neuronal apoptosis.