摘要:

Abstract –The administration of tetracycline to the growing child may cause discoloration and hypoplasia in developing teeth. Whether tetracycline may also cause changes in fully mineralized enamel and dentin, is still a matter of discussion. The present investigation examines the in vitro reaction between tetracycline chloride and enamel and dentin of extracted human teeth. Specimens were immersed in 0.5 mg/ml to 20 mg/ml aqueous tetracycline solutions. After 24 hr the specimens were sectioned and studied by fluorescence microscopy and microradiography. The tetracycline solutions, which were all very acidic, were found to cause 1) demineralization of enamel and dentin, 2) incorporation of fluorescent material in enamel and, notably, dentin; and 3) formation of yellow, rhombohedral crystals on dental surfaces, especially in the more concentrated solutions. No fluorescence was seen in totally demineralized dentin. The findings indicate that the incorporation of tetracycline into enamel and dentin is caused by physicochemical processes that may take place regardless of the developmental stage of the mineralized tissue

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00840.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –The influence of salmon calcitonin on the growth of teeth and alveolar bone, and on the healing of alveolar sockets has been studied in young male rats. The experimental animals received daily injections of salmon calcitonin 0.5 MRC‐U/kg body weight, whereas the control group received the vehicle. The rats were sacrificed at 14 and 28 days after the tooth extractions. Salmon calcitonin had no effect on the dry weight, calcium concentration and mineralization of the maxillary molars and the alveolar bone. Neither were there any significant effects of the hormone on the healing alveolar sockets. All sockets were healed after 4 weeks. The mineralization rate of molar teeth was only a quarter of that of tibiae, which was used as a refere

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00841.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –To study cytological changes in the migrating cell layer of the ameloblasts in the rat incisor with semithin Epon sections the ideal section plane would consequently be along the midsagittal plane of the incisor. However, the small dimensions and the complex three‐dimensional structure of the apical part of the odontogenic organ covered by alveolar bone make it difficult to orientate and position sections in the midsagittal plane. Serial sectioning of the apical half of the maxillary incisor in the horizontal and sagittal planes clarified the relation of the midsagittal plane of the odontogenic organ to the alveolar bone,andthe changes of the sectional profile of the odontogenic organ as a function of its position on the transverse axis of the incisor. From this information a method was designed whereby the two axes of the midagittal plane were marked directly on the block surface before sectioning,andthe position of sections in the midsagittal zone of the ameloblasts standardi

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00842.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –In the present study pellicle material was collected from human teeth 2, 4 and 6 hr after cleaning. The material obtained was examined by gel filtration, ion exchange chromatography on CM‐Sephadex and DEAE‐Sephadex with subsequent amino acid analyses of the major anionic component. No major changes were observed to occur either in the overall composition or in the main anionic component of the pellicle during the first

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00843.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –S. mutans and S. salivarius adherence to saliva‐coated and saliva‐uncoated hydroxyapatite was studied by transmission and high resolution scanning electron microscopy. No difference was observed between the saliva‐coated and saliva‐uncoated study series of adherence. The attachment of individual bacteria to apatite crystals was found to be mediated by cell wall projections. These electron‐dense structures were characteristically well formed in S. mutans, and even in S. salivarius the projections appeared to link the bacteria to the apatite. The site of attachment in the bacterial cell wall was always at the division area. We suggest that the possible metabolic activity at the cell wall division site, therefore, also works in the adhere

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00844.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –39 children were studied longitudinally at the age of 2, 3, and 4 yr for the colonization of S. mutans in plaque and saliva and for caries experience. S. mutans was found in 38% of the children, and the predominant serotype group was c/e/f. A total of 16 children got caries before the age of 4. Children who harbored S. mutans in their plaque at the age of 2, appeared to be the most caries‐active individuals. Their caries index values (number of decayed, missed and filled surfaces, dmfs = 10.6±5.3) at the age of 4 differed significantly from the values of children who harbored S. mutans later (dmfs = 3.4±1.8,P<0.005) or remained free from S. mutans infection (dmfs = 0.3±1.1,P<0.0003). It was thus concluded that the early establishment of S. mutans in the plaque of primary incisors indicated early and extensive caries attack in young primary den

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00845.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –Bacteroides sp. was isolated in human periapical osteitis and shown to be biochemically closely related to B. ruminicola ssp. brevis and B. capillus. Electron microscopic examination revealed an external cell‐wall layer (S‐layer). The fractionation of cells by various methods gave partially purified sheets corresponding to the observed layer with a hexagonal molecular arrang

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00846.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –Milk and saliva were tested in vitro as potential storage media for avulsed teeth. Developing monkey teeth were extracted and stored in milk or saliva for periods ranging from l to 6 h. The osmolality, pH, conductivity and number of viable bacteria in the media were determined after predetermined intervals during the storage periods. After the storage periods the teeth were either prepared for scanning electron microscopy or cultured for 24 h in Eagle's medium supplemented with3H‐thymidine. In the scanning electron microscope numerous adherent bacteria were seen covering the periodontal membrane after storage in saliva but none were found after storage in milk. The cultured teeth were sectioned and evaluated with autoradiography. Superficial parts of the periodontal membrane were rapidly injured by storage in saliva while the epithelial root sheath and the apical pulpal cells were affected at a later stage. Cells neighboring the cementoblasts incorporated3H‐thymidine after 6 h storage in milk but not after storage in saliva for the same length of time. It was concluded that the low osmolality in combination with bacteria which adhered to the periodontal membrane made saliva less suited than milk for long time storage of avulsed teeth. Furthermore, a viable layer of cells close to the root surface seemed to be a prerequisite for a successful healing without root résorption after replan

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00847.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –Body height, radius length and skeletal maturity were registered longitudinally in 48 boys with combined cleft lip and palate (CLP) and compared with measurements in a non‐cleft control group. Age range was from 6 to 20 yr. Skeletal maturity was evaluated according to the TW2 method. Distance and velocity curves for radius length and body height were determined by means of a computer program which for each month calculated the median and percentiles of the distribution. Compared to the control group the CLP boys were slightly shorter from 6 to 18 yr of age. The velocity curves revealed that pubertal growth maximum occurred on an average 6 months later in the CLP boys and that the pubertal growth spurt was less marked. However, the total growth period was prolonged thus enabling the CLP group to catch up with the control group. Skeletal maturity was retarded during the whole period when compared to normal children. It is suggested that the early feeding problems and recurrent infections of the upper airways combined with the surgical procedures account for an essential part of the delay in the present CLP gr

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00848.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract –The surface roughness of polished porcelain was investigated. The results showed that no significant differences between the two polishing methods used were found. The two evaluation methods, surface roughness measurements and scanning electron microscopy (SEM), are discussed and some recommendations are give

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1983.tb00849.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY