Reattachment of fractured anterior teeth-determining fracture strength using different techniques: an in vitro study.

AIM: The aim of this in vitro study was to evaluate and compare the shear bond strength of teeth reattached with sixth generation dentin bonding agent: Xeno III and microhybrid resin composite: Esthet-X, using three different techniques: (1) Simple reattachment, (2) overcontour and (3) internal dentinal groove. METHODOLOGY: A total of 70 human maxillary central incisors were selected and divided into four groups as follows. Group I: Control group comprised of 10 samples. Group II: Simple reattachment, group III: Overcontour and group IV: Internal dentinal groove. Groups II, III and IV comprised of 20 samples each. The teeth in three study groups were sectioned using a diamond disk and the fragment was reattached with Esthet-X and Xeno III using three different techniques. Specimens were stored in tap water for 24 hours and shear bond strength was determined using universal testing machine using a knife edge chisel (0.5 mm in cross-section) at a crosshead speed of 1 mm/minute. RESULTS: The results of this study showed following mean value of fracture strength in Kgf: Group I: Control-27.71; group II: Simple reattachment-9.78; group III: Overcontour-24.41; group IV: Internal dentinal groove-23.83. CONCLUSION: The overcontour technique had the highest strength recovery while the simple reattachment had the lowest. CLINICAL SIGNIFICANCE: The overcontour technique provided strength recovery almost similar to intact teeth emphasizing that tooth preparation influenced fracture resistance.

Carnitine as a free radical scavenger in aging.

Carnitine (4-N-trimethylammonium-3-hydroxybutyric acid) plays an important role in the translocation of acetyl moieties from the mitochondria into the cytoplasm for acetylcholine synthesis in the brain. Previous studies in our laboratory have shown that L-carnitine suppresses oxidative damage during aging. This study was carried out to see the effect of L-carnitine on the status of non-enzymatic antioxidants and lipofuscin accumulation in various regions of the aged rat brain. We observed a decrease in the status of ascorbic acid, glutathione and vitamin E in aged rats. Histological work showed that the accumulation of lipofuscin increased as a function of age. The extent of damage varied between the regions we have investigated. Supplementation of L-carnitine to aged rat improved the antioxidant status in a duration dependent manner. The accumulation of lipofuscin was also found to be decreased after L-carnitine administration. The data suggests that decrement of lipofuscin accumulation by L-carnitine may be partially due to its antioxidant promoting action.

Protective efficacy of L-carnitine on acetylcholinesterase activity in aged rat brain.

The purpose of this research was to study the activity of acetylcholinesterase in various regions of young and aged rat brain before and after L-carnitine supplementation. Two groups of male albino rats were used for this study (4 and 24 months of age). L-carnitine was administered intraperitoneally 300 mg/kg/d using physiological saline as a vehicle for 7, 14, and 21 days. The activity of acetylcholinesterase was measured in the cerebral cortex, the hippocampus, the hypothalamus, the striatum and the cerebellum. Highly significant variation was observed in a duration dependent manner in the hippocampus, the striatum, and the cortex of aged rats after L-carnitine supplementation when compared with young controls. Our results indicate that treatment of aged rats with L-carnitine restored the level of acetylcholinesterase.