An evaluation and comparison of the pulpal response to gold foil and indium alloy

All teeth restored with gold foil had pulpal changes marked by persistent hemorrhage, destruction of odontoblasts, and inflammation. Bacteria were found more frequently on cavity walls of teeth restored with gold foil and with increasing frequency for all materials as the observation period became longer. The presence or absence of bacteria could not be related to the pulpal response for either indium alloy or gold foil. Because this and previous studies indicated that gold foil in direct contact with prepared dentin surfaces produces pulpal injury, a base to protect the pulp is indicated. Indium alloy or another appropriate base could be used for the required pulpal protection.

Age-induced changes in the teeth and their attachment apparatus

Both the hard substances and the soft tissues of the teeth and their attachment apparatus are subject to constant change. This begins immediately after eruption and continues throughout life. An exact dividing line between changes which are physiological and pathological cannot always be drawn. Enamel undergoes attrition, and in addition its mechanical characteristics alter, owing probably to changes in diffusion conditions. The age-induced changes occurring in dentine are much more obvious, the biological properties of this hard substance being fundamentally altered. The dentine of older people is characterized by the continuous narrowing of the lumen of the dentinal tubule, increasing calcification, reduction in the amount of peritubular fluid and reduced sensitivity. In this process, dentine becomes able to assume the function of enamel as it wears. With age cementum undergoes continuous deposition, mainly functionally induced. It is evident, even macroscopically, that the volume of the pulp declines owing to the deposition of secondary dentine or of amorphous dentine with age. Histologically, young pulp differs fundamentally from that of the pulp of an older person. Regressive processes commence immediately after tooth eruption. The number, nature, properties and capabilities of the cells change, but the pulp does not suffer any appreciable loss of vitality. Circulation in the pulp is affected by deposition of hard substance in the apical part of the root canal. These processes are important in endodontics, and because of them different treatment methods have to be used for patients of different ages. The tooth supporting tissues are also subject to constant rearrangements, the physiological occlusal and mesial movements of the teeth being relevant here. All these structural and biological differences must be allowed for when therapy is being considered. They have not hitherto been taken sufficiently into account.

Pulpal survival in replanted and autotransplanted apicoectomized mature teeth of dogs with prepared nutritional canals

In the present study, an attempt was made to improve the possibilities for rapid revascularization and original pulp tissue survival in replanted and autotransplanted mature dog teeth by increasing the contact area between the pulp and the vascularized periradicular tissues. In 12 teeth, the root tip was resected and 3 additional nutritional canals were prepared in the apical 1/3 of the root at the time of the operation. Another 12 teeth were replanted or autotransplanted with intact roots. After an observation time of 120 days, the teeth were studied with microangiographic and histologic techniques. 11 of the teeth that were replanted or autotransplanted with intact roots showed total pulpal necrosis. Partial or total pulpal revascularization and repair was seen in all apicoectomized teeth with nutritional canals. The revascularized area of the pulp was somewhat larger in the replanted compared to the autotransplanted group of teeth. Signs of survival of the original pulp tissue were not seen. A comparison of the findings with those of previous studies on replanted and autotransplanted teeth with apicoectomized roots but without additional canals shows that the revascularization of the pulp did not proceed more rapidly in the apicoectomized teeth in the present study, although the contact area between the pulp and the periradicular tissues was enlarged through the preparation of the 3 artificial nutritional canals.