Evaluation of preventive treatment by risk of caries among 13-year-olds

Abstract Implementation of caries preventive treatment in relation to the risk of caries was studied among 13-year-olds (n=132) in two groups treated in the same public dental clinics in Helsinki: caries patients (n=100) had the greatest numbers of decayed teeth (DT+dt), 5.5 on average, whereas cavity-free patients (n=32) had intact teeth. Data taken from patients' personal oral health records served for evaluation of individual need for caries prevention, risk of caries, and preventive treatment given to each patient. Patients with any caries lesions or erupting teeth or poor oral hygiene were considered to be at risk of caries and in need of preventive treatment. The more caries lesions a patient had, the more prevention was expected to have been given. Preventive treatment of caries was weakly or only moderately in accordance with patients' individual needs and risk of developing caries, although patients with more caries lesions tended to have been given more preventive treatment than did those with none or only a few lesions. The majority of preventive measures given were applications of fluoride varnish, whereas motivation of and instruction in oral health care habits remained weak. However, patients whom their dentists had judged to be at high risk of caries received more intensified preventive treatment than did other caries patients. As a conclusion, intensification of caries prevention among high-risk patients is still needed. Dentists should always consider each patient's risk of developing caries to improve quality of preventive treatment.     

Identification of human antigenic epitopes in an alanine-rich repeating region using sera from hu-PBL-SCID mice immunized with a surface protein antigen of Streptococcus mutans

A 190-kDa surface protein antigen (PAc) of Streptococcus mutans is considered to play an important role in dental caries. To identify antigenic epitopes of the PAc in humans, we immunized severe combined immunodeficient (SCID) mice with re-combinant PAc that was transplanted with human peripheral blood mononuclear cells (PBMC). The reactivities of the sera from the immunized hu-PBL-SCID mice to the recombinant PAc and 24 19-mer synthetic peptides covering the alanine-rich repeating region (A-region) presented in the PAc molecule were then examined. The results showed that the immunized mice produced a significant recombinant PAc-specific human antibody, and among 24 19-mer peptides, 6 19-mer peptides showed a strong reaction with the antibodies. In addition, 4 19-mer peptides containing human antigenic epitope in a donor were identified with enzyme-linked immunosorbent assay (ELISA) inhibition assays using the recombinant PAc protein. In this study, the SCID mouse was useful in identifying human antigenic epitopes.     

Intraepithelial antigen‐presenting cells in the keratitied mucosa around teeth and osseointegrated implants

The presence and distribution of intraepithelial antigen‐presenting cells was studied in the keratinized mucosa around healthy osseointegrated implants and teeth. Vimentin, cytokeratins, HLA‐Dr, CD18, ICAM‐I and CDla‐positive cells were assessed by a 3-stage ABC immunoperoxidase system in serial sections from clinically characterized sites. A total of 11 biopsies (7 adjacent to osseointegrated dental implants and 4 adjacent to teeth in healthy volunteers) were qualitatively and quantitatively analyzed. All biopsies displayed the presence of a small inflammatory infiltrate subjacent to themost coronal portion of the junctional epithelium. Intraepithelial antigen‐presenting cell markers were present both around implants and teeth. The observations were consistent with the presence of functional local major histocompatibility complex Class II restricted antigen presentation. Quantitative differences were observed by analysis of variance in terms of different locations within the same section (i.e. junctional epithelium vs oral epithelium) and in terms of the source of the biopsy (i.e. implants vs teeth). The significance, if any, of the observed quantitative difference is discussed in terms of different maturity of the local immune response and possible environmental differences. It is concluded that clinically healthy keratinized mucosa around osseointegrated dental implants shares functional similarities with normal gingiva in terms ofantigen presentation. These results further contribute to the characterization of a functional local immune response that represents the basis for long‐term clinical success of osseointegrated dental implants.     

Increased bonding of a glass-ionomer cement to dentin by means of FeC13

Abstract – It was previously demonstrated by other authors that FeC1₃ is readily sorbed by dentin surfaces. The main purpose of the present work was to investigate the possibility of increasing the bonding of a glass-ionomer cement to dentin by means of FeC1₃. It was found that the strength of the bond was approximately doubled when the dentin was treated with an acidic cleansing agent followed by an application of an aqueous solution of FeC1₃ of suitable concentration.     

Effect of casting methods on accuracy of peridental restorations

Abstract – The present study has shown that the accuracy of peridental gold alloy castings depends 1) on the type of casting machine used, 2) on the diameter of the casting sprue, and 3) on the strength properties of the investment material. The dependence between the accuracy and the three factors mentioned is based on erosion of the investment mold by the inflow of the liquid casting alloy. The vacuum casting technique proved to be a more gentle casting method than centrifugal and vacuum/pressure techniques.     

Enhanced emigration of crevicular leukocytes mediated by factors in human dental plaque

abstract – The present investigation was performed to study whether a filtrate from human dental plaque when applied topically to the gingival margin enhances gingivitis. Four-day-old plaque was sampled from 20 dental students. The plaque samples were pooled, suspended in NaCl, homogenized, centrifuged and filtered. The capacity of the plaque filtrate to attract neutrophil leukocytes was determined by measuring the number of leukocytes (a) which migrated into wound chambers containing the filtrate and (b) which could be sampled from the gingival crevices of dogs and monkeys after repeated topical application of the filtrate to the gingival margin. Gingivitis was assessed by gingival exudate measurements. The results showed that substances present in human dental plaque are highly chemotactic for neutrophil leukocytes. The filtrate stimulated enhanced emigration of leukocytes into the gingival crevices and enhanced gingival exudation. The observations indicate that a plaque filtrate may enhance vascular and cellular changes similar to those seen in incipient gingivitis.     

Pharmacokinetics of parenteral paracetamol and its analgesic effects in post-operative dental pain

Summary A double-blind, randomised, crossover trial was undertaken to compare the analgesic effects of a single dose of paracetamol (1000 mg i. v.) with placebo in the immediate post-operative period following removal of impacted lower third molars. There was no significant difference in the pain relief between paracetamol and placebo in the first hour following injection. Thereafter, there was significantly less pain (P<0.05) after treatment with paracetamol than after placebo. Plasma concentrations of paracetamol were measured and pharmacokinetic variables were determined. Over the four hour period of investigation there was no clear relationship between analgesia and paracetamol concentration in either central or peripheral compartments.     

The ultrastructure of fluorosed human dental enamel

abstract — More than 80 specimens of enamel from 20 ground sections of eight teeth showing severe dental fluorosis have been examined in the transmission electron microscope. The study has shown that the prisms have normal size and form, but are surrounded by large periprismatic gaps. The individual crystals commonly appear in cross sections as regular, flattened hexagons with an average width of 91 nm and average thickness of 45 nm. Particularly in the tail regions and at prism peripheries, extensive intercrystalline spaces were found. The crystal lattice demonstrated a spacing of 0.82 nm. Demineralization of thin sections with PTA showed a preferential dissolution of the crystal centers. Based on the ultra-structural observations it is proposed that the hypomineralized regions of fluorosed enamel are produced by an arrest of enamel maturation, possibly due to toxic damage to the ameloblasts in the absorptive or maturative phase of their life cycle.