摘要:

Factors influencing the shear strength of incremental curing of three different composite resins were examined. The first increment was cured under different surface conditions, in air, or under a coverglass. A separate experiment studied the effect of curing in nitrogen atmosphere. There was no difference in the shear strength of the specimens if the first increment was created in air or under a coverglass. One material (Heliomolar RO) showed higher shear strength when cured in increments and one when bulk-cured (Herculite XR). Curing increments in a nitrogen atmosphere increased the shear strength for two of the three materials tested (P50 and Heliomolar). The results showed that the bond strength between the increments of composites was influenced by the surface properties of the composites themselves after they had been cured under the different conditions; it was also affected by the inherent chemical and physical properties of the materials utilized.

ISSN:0001-6357    

DOI:10.3109/00016359609003537

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Three groups of extracted human teeth were sectioned longitudinally into experimental and control halves. The enamel surfaces of the three groups of teeth were pretreated with 37% H3PO4for 1 min, 0.5 M NaClO3for 2 h, or water rinsing for 10 min. The experimental halves of the three groups received an application of 1% TiF4for 1 min and were washed with deionized water. The tooth specimens were men immersed in synthetic saliva for 24 h at 37°C before sampling for measurement of fluoride uptake. An acid etching technique was used to determine the uptake of fluoride by measuring both fluoride and calcium concentrations in the solution collected from each etched sample. A significantly higher uptake of fluoride was found in teeth rinsed in water and etched with 37% H3PO4 than in teeth pretreated in 0.5 M NaClO3. It seems that the organic components in enamel play an important role in the fluoride uptake after the topical application of TiF4.

ISSN:0001-6357    

DOI:10.3109/00016359609003538

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The effect of a low dose of glucocorticoids on dentin formation and progression of dental caries was studied in young rats. The animals were inoculated in the mouth withStreptococcus sobrinusand fed ad libitum a high-sucrose, a high-starch, or a reference diet. The cortisone or placebo pellet was implanted subcutaneously in the back of the necks of the animals. After a 6-week experimental period the areas of dentin formation and dentinal caries were quantified planimetrically. Schiff s staining was used to classify caries. Cortisone reduced the dentin formation both in high-starch and reference diets, but it did not further affect the reducing effect of the high-sucrose diet on dentin formation. Cortisone did not affect the number or severity of dentinal carious lesions.

ISSN:0001-6357    

DOI:10.3109/00016359609003539

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The effect of cyclophosphamide (Cy) on tooth development was studied in molars of 18 young Sprague-Dawley rats. Doses of 30 mg/kg body weight of Cy dissolved in 1 ml 0.9% NaCl were administered to 18 experimental rats and 1 ml 0.9% NaCl to 18 control rats at 10 and 13 days of age. The most obvious changes in the experimental teeth could be seen in the developing pulp of the third molar and developing roots of the first and second molars. Wide cell-free areas appeared in the third molar 2 days after the last injection; later these areas turned into mineralized osteodentin. Similar areas could be observed also in the roots of the first and second molars. These changes were related to the developmental stage of the area.

ISSN:0001-6357    

DOI:10.3109/00016359609003540

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Types X and VI collagen and fibrillin were localized by in situ hybridization and immunohistochemical methods in the mandibular condyles of rats, and the response of these molecules to post-weaning diets of soft food, ordinary pellets, or hardened pellets was studied. Type X collagen was synthesized, particularly in conditions of soft food consistency, by cells in the perichondrium-periosteum and in me bone and by cells at the erosion front between cartilage and bone. Type X collagen synthesis diminished under higher compression forces due to mastication and with increasing age. Type VI collagen and fibrillin were synthesized by cells in the perichondrium-periosteum and by chondrocytes and by stromal osteoblasts and were not modified by higher mechanical forces. In contrast to previous findings in the growth plate of long bones, type X collagen in die mandibular condyle was not synthesized by hypertrophic chondrocytes but was associated with cells of the osteoblastic rauier than the chondroblastic phenotype.

ISSN:0001-6357    

DOI:10.3109/00016359609003541

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The dental and periodontal status, oral hygiene, and dental visit habits of 250 residents in long-term care (LTC) facilities for the elderly in a suburban community in Norway were recorded. The findings were compared with the data from an identical examination of the residents in the same LTC facilities in 1980. In 1993 the mean number of remaining teem per person was 11.7 (CI = 10.3-13.1). The mean number of filled teeth was 5.1 (CI = 4.1-6.0), and the mean number of decayed teeth was 1.8 (CI = 1.4-2.2). The mean number of residual roots per person was 0.8 (CI = 0.5-1.1). Periodontal pockets exceeding 4 mm was recorded on 5% of all teeth. In general, the oral hygiene was poor. Edentulousness had decreased from 80% in 1980 to 54% in 1993, and more remaining and filled teeth and fewer residual roots per person were observed in the 1993 population. The findings show that the objective need for resources to prevent periodontal disease and caries among elderly patients in LTC facilities today is higher than previously.

ISSN:0001-6357    

DOI:10.3109/00016359609003542

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A retrospective study of patients hospitalized for infections associated with partially erupted third molars during a 10-year period (1985-94) showed a total of 17 cases: 6 women and 11 men, aged 18 to 57 years. Eight patients were in the third decade. No deviation from me habits of the general population with regard to cigarette smoking and alcohol consumption or overrepresentation of general health problems was found. All infections were of pericoronal origin. Bacteriologic cultures from six patients showed mixed aerobic—anaerobic oral flora, without any penicillin-resistant strains. The incidence rate of serious orofacial infections associated with partially erupted third molars was calculated to be 0.016 cases per year per 1000 patients at risk.

ISSN:0001-6357    

DOI:10.3109/00016359609003543

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

There are great variations in dentists' choice of treatment. The aim of this study was to evaluate a Patient Paper Case (PPC) technique to investigate such variation, adjusted for prosthodontics. The questionnaire was sent to all 131 general practitioners (GP) in the Public Dental Service inÖrebro County and to all 100 GPs in private practice in Skaraborg County, Sweden, with 81% responding. There were three PPC questions, concerning 1) crown therapy or amalgam/composite filling, 2) fixed or removable partial denture, 3) fixed partial denture or single implant restoration. Respondents were asked to assess 13 or 14 items concerning the patient, dental conditions, and own skills. There was great variation in responses. In factor analysis four factors were found to capture between 54% and 60% of the variance of the items. They were interpreted as a time factor, a patient subjective factor, a clinical factor, and finally, for the PPC 1 and 2, a general health factor. The Swedish insurance regulations of single implant therapy, mandatory caries/filling-free, and vital adjacent teeth were reflected in the factor solution of PPC 3. It is concluded that the PPC method is feasible and useful in studies of clinical decision-making in prosthodontics.

ISSN:0001-6357    

DOI:10.3109/00016359609003544

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Fifty-two male growing rats were randomly divided into three groups. The first group (n= 18) received a hard deficient diet, and the second (n= 18) a soft deficient diet. The control group (n= 16) was fed the normal hard diet. At the beginning and in the middle of the 28-day experimental period oxytetracycline was injected. Two representative coronal sections of the snout and the corresponding contact microradiographs were analyzed. The bone mass of die premaxillary and nasal bones seemed to be less in die two deficient diet groups than in the normal one, due to an increased endosteal bone resorption and decreased bone formation. No difference in the bone apposition rate and pattern could be seen between me deficient hard and soft diet groups, except in the dorsal part of the premaxilla, where the bone formed in the first half of the experiment was markedly more resorbed in die deficient soft diet group during die remaining period than in the deficient hard diet group. The morphology of the sutures was influenced by the altered function, since the sutural space became narrower, and premature obliterations of the intemasal suture were observed in the deficient soft diet group. In conclusion, poor bone quality was observed in the skull of rats fed a low-calcium and vitamin-D-deficient diet, with less bone mass than in normal conditions. Masticatory function was a significant factor influencing bone remodeling and sutural growth even in situations in which a metabolic bone disturbance exists.

ISSN:0001-6357    

DOI:10.3109/00016359609003545

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A retrospective study of patients hospitalized for treatment of cystic lesions associated with retained third molars during a 10-year period showed a total of 32 cystic lesions in 25 patients. Twelve cysts were or had been infected, and seven were detected by routine radiographic investigation. Male to female ratio was 1.8, and mean age, 44,7 years; range, 16-76 years. Three of four lesions were found in the mandible. A compromised general health situation was found in eight patients. Mean largest diameter of the lesions was 48 mm; range, 26-72 mm. No differences in patient age or size of the lesions were found between infected and non-infected cases. All cysts were treated surgically, with a complication rate of 19%. Infection and age did not influence complication rate. Crude incidence rate was 0.038 per year per 1000 at risk—that is, persons more than 16 years old with at least one retained third molar present.

ISSN:0001-6357    

DOI:10.3109/00016359609003546

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor