ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00686.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryRestoring broken down non‐vital teeth implies in general the provision of a post and core foundation. Many materials and techniques have been introduced for this purpose in recent years. In this article the advantages and disadvantages of the cast and the non‐cast post and core are discussed. The problems involved with the application of the post and core are reviewed. An efficient procedure for restoring a broken down tooth with a prefabricated post in combination with a composite core is presen

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00687.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryAdhesive tape applied to the fitting surface was used to study the early colonization of acrylic palates in six subjects. Streptococci were major constituents of the plaque accumulated on the tape over the first 3 days.Bacterial colonization of the tape discs was selective in that dextran‐producing streptococci constituted a greater proportion of the total streptococcal count after 15 min compared with that of the initial sample and saliva, while the converse was true forStreptococcus salivarius. Scanning electron microscopy showed that denture plaque development started in grooves and depressions on the surface of the tape, and became more extensive with time. Comparison of the colonization of tape and acrylic discs in one individual demonstrated that the tape was a suitable model forin vivocolonization of dentures or orthodontic appliance

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00688.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Twenty paired approximal amalgam restorations (E*) extended and unextended (NE†) placed in twelve patients were followed up for 10 years. Measurements of the distance between the alveolar crest and (a) the apical margin of the filling (E and NE) or (b) the cementoenamel junction of the untreated control surface (C) were performed 1, 4 and 10 years following restoration placement. The bone loss associated with NE filling did not differ significantly from that of the control group and amounted to 0.4mm in 10 years.The 10‐year cummulative bone loss adjacent to the extended restoration (E) was 1.07 mm. Bone loss associated with the E restoration was significantly higher (P<0.001) than that of the NE and control groups at every period measured. During the first 4 years the yearly bone loss of the E group was 0.14 mm and then decreased to 0.08mm during the last 6 ye

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00689.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryA previous study has shown that the addition of small amounts of tin to γ1leads to the formation of a SnHg intergranular precipitate. The purpose of this study was to determine the effect of this precipitate on the creep of γ1. Two groups of samples were investigated. Group I included a series of γ1samples with 0, 1, 2, and 3wt% Sn fabricated by a sintering technique at 55°C and 125mN/m2for 72 h. Group II contained the same samples as in Group I that were further annealed at 60°C for 2000 h. Annealing was carried out to allow γ1grain growth and equilibrium distribution of Sn at grain boundaries. Creep tests were conducted according to the American Dental Association Specification 1. The microstruc‐tures of all samples were characterized by scanning electron microscopy. The creep of γ1was found to be controlled by the intergranular precipitate when the Sn concentration was above 1%. For a specific concentration of Sn, i.e. the integranular precipitate, creep was dependent on the distribution of Sn and not on the γ1grain size. The more nearly continuous precipitates found in annealed samples favoured hig

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00690.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe series consisted of sixty subjects selected from the patients who attended the prosthetic or restorative departments of the Institute of Dentistry at the University of Kuopio in 1978–82. All the patients had had a mutilated or reduced dental arch in the upper or lower jaw for at least 1 year. They had received no prosthetic treatment and little restorative treatment.Helkimo's indices were registered in the first examination. After the first examination the pre‐prosthetic treatment was performed on all the patients. The second examination was after 18 months. Then Helkimo's indices were registered again. The prosthetic treatment had then been performed on thirty‐nine patients (group A). The control group consisted of nineteen patients without prosthetic treatment (group B).The changes in Helkimo's indices were analysed statistically (Mann‐WhitneyU‐test). The changes in the anamnestic index were not significant in either group while the changes in the dysfunction and occlusal index were highly significant in both groups

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00691.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryAir‐powder abrasive systems are used in dentistry to remove dental plaque, calculus and stain from the surfaces of teeth. A model system consisting of a thin layer (14 μm) of vacuum‐deposited aluminium was used to demonstrate the effectiveness of such a system. Photomicrographic analysis showed two distinct areas of removal: an inner area where removal of aluminium was complete, surrounded by an area where removal was incomplete.With the aid of a relocation pin attached to the nozzle of the instrument it was demonstrated that nozzle–target distance, the air pressure input, the flow of water and the time of operation were all factors which affected the clinical efficiency of the inst

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00692.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryIn addition to the graphical representation of swallowable composition (SC) of masticated food, an index—the coefficient of swallowable composition (CSC)—has been proposed in this study. This index was tested using hard‐baked soya beans on various types of dentitions. The value of CSC ranged from +24 to −14 in full dentition and full denture wearers respe

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00693.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryAnin vitrostudy was conducted in which a range of amalgam alloys was condensed into Class I cavity preparations. The force of condensation and increment size were varied to determine the effect of these operator variables on the adaptation, of the alloys investigated, to the prepared cavity walls. Specimens were sectioned, metallographically polished and examined using light and scanning electron microscopes. For each specimen ten random points on the pulpal and both vertical walls were selected to measure the adaptation of the amalgam to the tooth structure.For the Class I cavity preparation the adaptation of all alloys to the vertical walls was better than the adaptation to the pulpal walls. The overall adaptabilty of the alloy did not appear to be determined by the particle size, shape or composition. Condensation force was the most important factor in influencing adaptation of amalgam to the cavity walls. Heavy condensation forces produced better adaptation for all alloys particularly when condensing small increments.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00694.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe adaptation of a range of amalgam alloys to the cavosurface margin of Class I cavity preparations was examined for two condensation techniques. The marginal contour of amalgam condensed into the cavity preparation and packed approximately 1 mm past the cavosurface margin was compared with amalgam margins of restorations which were packed to final contour with minimal carving. The effect of burnishing and/or polishing the cavosurface margin was compared with carving the amalgam to the cavosurface margin. Specimens were sectioned, metallographically polished and examined using a light microscope.The technique of overpacking amalgam produced a greater number of acceptable amalgam margins at the cavosurface margin than the condensation technique of packing to final contour, the best cavosurface margin was produced when specimens were burnished and polished, the carved margin being the least desirable. The cuspal incline also influenced the quality of the marginal finish with the difficulty of marginal finishing increasing with the steepness in cuspal incline.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1987.tb00695.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY