ABSTRACT
A laboratory test of the sharpness and penetration resistance of different brands of dental needles was undertaken. Both properties are essential when pain during injection is discussed. Using a Strograph in combination with a piece of stretched chamois leather resembling the mucous membrane, graphs were obtained for each needle tested and evaluated with reference to maximum penetration resistance at the actual point of puncture and to the smoothness of the further insertion through the leather. The findings gave a relative characteristic of each product based on a trial of 20 needles selected at random from each batch of 100 needles.
Subject(s)
Needles/standards , Dental Instruments , Disposable Equipment , Evaluation Studies as Topic , Injections/instrumentationABSTRACT
The aim of the present study was to evaluate qualitatively and quantitatively the effect of metatarsal transplantation on the mandibular condylar region. Two series of experiments were performed in four groups of Rhesus monkeys, a fifth group served as a nonoperated control group. The surgical procedures involved either the condyle and part of the ramus or the condyle only. Following the postoperative observation period the skulls of the animals were examined macroscopically, measured anthropologically and measured indirectly on vertical cephalograms. A new method developed by the authors for description of facial asymmetries was used. In all of the operated animals well-functioning joint structures were revealed, though all experimental groups showed the classical deformation features. Continued growth of the transplant was observed in only one case. The facial asymmetries were described as angular deviations from the true symmetry axis. No significant difference between the transplant and the corresponding nontransplant groups was detected for the two kinds of resection performed. However a difference in the degree of asymmetry between the ramus resection group and the condylectomy group was seen. It is concluded that a metatarsal transplant does not prevent the development of facial asymmetry following plain condylectomy or resection of the posterior third of the ramus of the mandible including the condyle.
