ABSTRACT
The aim of this study was to determine the susceptibility of newly erupted and old permanent teeth to artificial, caries-like attacks. Two groups of caries-free teeth were used. Group 1 consisted of 38 teeth extracted for orthodontic reasons (9-12-yr-old children); group 2, of 40 teeth extracted for periodontal reasons (45-65-yr-old patients). After thorough cleaning, a test window was isolated on the incisal two-thirds of the buccal surface. After demineralization with 6% HEC gel at pH 4.9 for 8 days, longitudinal ground sections were prepared for imbibition studies in polarized light and for secondary ion mass spectrometry (SIMS). In the young teeth, the lesions appeared to be uniform in their extension in the enamel, whereas the old teeth showed less marked and thinner surface zones and greater depth of the positively birefringent body of the lesion. Polarized light microscopy and SIMS data support the hypothesis that there are different enamel pathways in the initiation of the natural carious process.
Subject(s)
Aging/physiology , Dental Enamel/drug effects , Tooth Demineralization/physiopathology , Age Factors , Aged , Cellulose/analogs & derivatives , Cellulose/pharmacology , Child , Dental Enamel/chemistry , Dental Enamel/pathology , Humans , In Vitro Techniques , Mass Spectrometry/methods , Microscopy, Polarization , Middle Aged , Tooth Demineralization/pathologyABSTRACT
The pattern of restorative therapy with amalgam of 38 thuringian dentists were checked up over a period of 4 weeks. The indications of the 3644 in these time applicated amalgam restorations were in 42% of all cases primarily caries, in 22% secondary caries and in 24% noncaries caused reasons. Occlusal caries was dominant in adolescents and young adults. Patients older than 24 years had a higher risk of approximal caries and root caries is becoming a clinical problem in patients older than 54 years. 61% of the replaced amalgam restorations have had a function period over 5 years. Prevention, early restorative therapy and consequently a recall system in connection with correct indication are the most important factors for a long time of amalgam restorations and successful dental treatment.
Subject(s)
Dental Amalgam , Dental Restoration, Permanent , Adolescent , Adult , Dental Amalgam/adverse effects , Dental Caries/etiology , Female , Humans , Male , Middle AgedABSTRACT
The remineralization process in the oral environment is the presumption of enamel structural integrity and function. Strong or frequent acid attacks may be followed by pathological alterations. Remineralization of human enamel after phosphoric acid demineralization was investigated. 4 subjects were selected for in-vivo experiments using specialized oral applicators with 52 etched enamel specimen, incorporated for 10 or 28 days and 59 probes remineralized in a synthetic mineral solution over the same period. Mineral deposition and rehardening took place. After 28 days the reparation of acid defects was incomplete. The in-vitro remineralization is less pronounced and does not reflect the complex remineralization mechanism in vivo.
Subject(s)
Dental Enamel/ultrastructure , Tooth Remineralization , Adolescent , Bicuspid , Hardness Tests/methods , Humans , In Vitro Techniques , Microscopy, Electron, Scanning , Microscopy, Polarization , Surface Properties , Tooth Remineralization/methodsABSTRACT
The calcium determination by atomic absorption spectroscopy is impaired in samples which contain 1-hydroxyethylidene-1,1-bisphosphonate. We describe possibilities to avoid these bisphosphonate-mediated interferences of calcium measurement.
Subject(s)
Calcium/analysis , Diphosphonates/analysis , Humans , Spectrophotometry, AtomicSubject(s)
Composite Resins/pharmacology , Polymethacrylic Acids/pharmacology , Bisphenol A-Glycidyl Methacrylate , Dental Caries/therapy , Dental Enamel/drug effects , Dental Enamel/ultrastructure , Dental Restoration, Permanent , Drug Evaluation, Preclinical , Humans , Methylmethacrylates/pharmacology , Microscopy, Electron, Scanning , Surface PropertiesABSTRACT
Acetate buffers were passed through small hydroxyapatite columns and the column effluents were analysed for calcium and phosphate. Changes in the pH of the column effluents were also measured. As long as the pH of the column effluent was higher than about 5.5, only calcium was eluted from the column. However, when the pH fell below 5.5, the rate of calcium elution decreased and phosphate elution increased until calcium and phosphate elution reached constant values. Pretreating the hydroxyapatite with sodium fluoride or 1-hydroxyethylidene-1,1-bisphosphonate accelerated the drop of the pH and reduced the initial Ca/P ratio in the column effluent. We suggest that these results are due to the formation of a pH gradient along the progressing buffer fron with calcium and phosphate liberated from the hydroxyapatite reprecipitating to form calcium-poor minerals.
