摘要:

The effect of splinting upon periodontal healing after replantation was studied in 21 green Vervet monkeys (Cercopithecus aethiops). Two maxillary incisors were extracted in each monkey and the teeth were endodontically treated extraorally. One incisor was replanted after 18 min. whereas the other was replanted after 120 min. In 8 monkeys an orthodontic band-acrylic splint was applied for 6 weeks. In 6 monkeys the replanted teeth were splinted for 2 weeks. In 7 monkeys no splinting was carried out. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histologically. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium and periapical inflammatory changes. All teeth replanted after 120 min. showed extensive ankylosis irrespective of the splinting method. In the 18-minute replantation group, the frequency and extent of replacement resorption was significantly lower in the non-splinted teeth compared to the splinted teeth. No significant changes were found among the other examined histologic parameters. It is concluded that splinting did not improve periodontal healing after replantation of mature teeth in monkeys and apparently exerted a harmful effect upon periodontal healing in teeth replanted after a short extraoral period.

ISSN:0001-6357    

DOI:10.3109/00016357509004636

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

The purpose of this study was to examine tooth mobility changes after replantation of avulsed permanent teeth and to correlate these data with radiographic and clinical findings. The material consisted of 35 patients in whom 40 accidentally avulsed permanent incisors were replanted. Mobility testing was performed with a modified macroperiodontometer. Combined clinical, radiographic and mobility findings indicated that healing after replantation could be divided into the following modalities: 1.Normal healingwith slightly increased or normal mobility values and no radiographic sign of progressive root resorption. 2.Permanent replacement resorptionwith lowered mobility values and radiographic sign of replacement resorption. Decreased mobility values indicate that ankylosis was usually evident 5 weeks after replantation. At the same time, it was possible to diagnose the ankylosis by the percussion test. The radio-graphic examination first revealed ankylosis 8 weeks after replantation. 3.Transient replacement resorption(not previously described) with lowered mobility values which later became normal. Radio-graphic signs of a transient replacement resorption were present in some cases. 4.Inflammatory resorptionwith increased mobility values and radiographic sign of inflammatory root resorption. Mobility values tended to become normal when inflammation subsided as a result of root canal treatment.

ISSN:0001-6357    

DOI:10.3109/00016357509004637

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

The purpose of the present work was to investigate a possible relationship between the composition of composite restorative resins and their wall-to-wall polymerization contraction. The investigated brands contained bis-gma diluted with varying amounts of one or two low-viscous monomers. The wall-to-wall contraction was measured microscopically as the maximum gap width in the dentin part of cavities in extracted human teeth. A positive correlation between gap width and amount of diluting monomer was found, with commercial composites and with non-composite, experimental resins. Addition of up to 75°by weight of an inorganic filler to a monomer mixture similar to those found in commercial composites had no effect on the width of the contraction gaps. With non-composite experimental resins the gaps were found to increase with the amount of catalyst.It was concluded that the composition of the organic phase is of primary importance for the size of the wall-to-wall contraction of composite restorative resins.

ISSN:0001-6357    

DOI:10.3109/00016357509004638

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

The existence of complexes (clusters) in the alloy system Au-Cu was studied through determination of the copper activity for 14 different compositions at temperatures around 1100 K. The experimental data were obtained from emf measurements using stabilized ZrO2as the solid electrolyte. Using an equilibrium calculation method the relative amounts of»free»gold, of»free»copper and of complexes were indicated. The best fit to experimental data was obtained with a model assuming the existence of the complexes Cu3Au. CuAu, CuAu3and CuAu9.

ISSN:0001-6357    

DOI:10.3109/00016357509004639

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

In order to study the function and the level of activity of the mentalis and the orbicularis oris superior muscles in subjects with different lip morphology, an electromyographic investigation was carried out on ten children with normal lip position (competent lips) and ten children with lip incompetence. The underlying skeletal and dento-alveolar morphology was studied by cephalometrics. All the children had malocclusions, but had received no orthodontic treatment. It was found that a relaxed lip position with no EMG activity could be taken up by all the children in both groups. Lip closure, mastication, and swallowing were performed with a significantly greater activity in subjects exhibiting lip incompetence than in those with normal lip position. The analysis of cephalometric values in relation to lip posture and perioral muscle activity showed that subjects with incompetent lips and increased perioral muscle activity had great lower anterior face height, high mandibular plane angle, postnormal skeletal jaw relation, and increased lower incisor proclination.

ISSN:0001-6357    

DOI:10.3109/00016357509004640

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

The aim of the present study was to assess the penetration of chlorhexidine through the oral mucosa. Ten albino guinea pigs had the oral cavity exposed to 0.2 %14C-labelled chlorhexidine for 1 min after initial rinsing with water. Five animals were sacrificed after 30 min and 5 after 60 min. Biopsies from the tongue, palate, gingiva and the buccal mucosa were frozen in liquid nitrogen, cut, fixed and prepared for autoradiography. The surface layers of the epithelium contained the greater part of the labelled material in sections from the tongue, palate and gingiva. Below these heavily labelled surface layers a scattered distribution was noticed throughout the epithelium. Sections from the buccal mucosa showed less surface labelling, but a slight accumulation of label close to the basement membrane was seen. Though labelling was more abundant in the epithelium than in the connective tissue, chlorhexidine had also penetrated into the connective tissue in sections from the buccal mucosa, the gingiva and the ventral side of the tongue.

ISSN:0001-6357    

DOI:10.3109/00016357509004641

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

The bonding of a resinous sealant material to acid-etched sound human enamel was studied by means of a scanning electron microscope. Both the resinous bonding surfaces and the respective enamel surfaces of the specimens were exposed for inspection by dissolving one half of each specimen in hydrochloric acid so that only the resin matrix remained. Acid etching caused selective dissolution of the surface enamel so that, compared with the rod cores, more inter-prismatic substance was dissolved. The bonding surfaces of the resin material showed exact replication of the corresponding etched enamel. Tags of sealant, approximately 10 microns in length, were found on the acid-etched specimens.

ISSN:0001-6357    

DOI:10.3109/00016357509004642

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor