Marginal gap formation and fluoride release of resin-modified glass-ionomer cement: effect of silanized spherical silica filler addition

The purpose of this study was to investigate the effects of silanized spherical silica fillers (SF) on the immediate and 24-hour marginal gaps of resin-modified glass-ionomer cement (RMGIC) in tooth cavities. In correlation with marginal gap formation in the tooth cavity, these influencing factors were also examined: marginal gap and setting shrinkage of cement in the Teflon mold, as well as the shear bond strength to tooth substrate. Moreover in correlation with caries prevention, fluoride release was examined too. In this investigation, the fillers were mixed into the RMGIC powder (Fuji II LC EM). Untreated spherical silica filler (UF)-added RMGIC was used as a comparison. When compared with the control (i.e., original RMGIC), the addition of SF significantly decreased immediate marginal gap in tooth cavities and setting shrinkage in Teflon mold up to 63% and 66% respectively. Fluoride release was significantly reduced too. Apart from these results, this study showed that addition of 5 wt% SF increased the shear bond strength to human enamel and dentin.     

Evaluation of condylar translation by sonography versus axiography in orthognathic surgery patients

PURPOSE: This study compares measurement of the condylar translation by sonography or axiography in preoperative assessment and follow-up of orthognathic surgery patients. PATIENTS AND METHODS: Forty-seven moderately dysgnathic patients had consecutive examinations by axiography and sonography in a blind fashion at a single time point by 2 observers. Thirty-nine different dysgnathic patients, scheduled for isolated Le Fort I osteotomy, had preoperative condylar translation and 24-month follow-up measured randomized by either axiography (25 patients as control group) or sonography (14 patients as study group). RESULTS: The examination time for axiography was 20 minutes average versus 2 minutes for sonography. The mean differences were 1.7 mm in opening, 2.1 mm in protrusion, and 3.3 mm for mediotrusion. Pearson's proportionality quotient was r = 0.75, analysis of variance (P <.95, F = 3.9, alpha =.05 significance level) was not significant. The 24-month longitudinal follow-up showed a Pearson's proportionality quotient of r = 0.7 between study and control group, and no significant difference in analysis of variance (P <.075, F = 2.81, alpha =.05 significance level). CONCLUSION: Sonography proved adequate for assessment and follow-up of condylar translation compared with axiography in orthognathic surgery patients. Temporomandibular joint sonography was faster and more comfortable, allowed 1-week postoperative examination and reexaminations, and was equally exact. Anatomic details like joint degeneration and disc displacement could be assessed. However, sonography did not measure the inclination of the condylar track.     

Differential expression of CR3, FcɛRll and FcγRlll on Polymorphonuclear leukocytes in gingival crevicular fluid

Polymorphonuclear leukocytes (PMNLs) are the most numerous cell population among the cellular infiltrates in gingival crevicular fluid (GCF) and play important roles in the host-defensive system in the gingival crevices. We determined the percentage of neutrophils, cosinophils and basophils in total PMNLs by light microscopic observation using Randolph-methylene blue staining, then assessed flow cytometric differences in the expression of CR3, FcγRIII, FcɛRII. LFA-1α, and LFA-Iβ on PMNL in GCF and peripheral blood (PB) from 21 patients with adult periodontius (AP) and 13 healthy donors. Percentages of basophils and eosinophils were higher in GCF than in PB. In both AP patients and healthy subjects, expression of CR3 and FcɛRll was higher while FeγRIII was lower in GCF than in PB. The statistical analysis showed that the expressions of FcγRIII and FcɛRII on GCF PMNLs were lower in AP patients than in healthy subjects. Expressions of LFA-1α and β on GCF were similar to those on PB PMNLs. PB PMNLs stimulated in vitro with Porphyromonas gingivalts culture supernatant and fMLP displayed an expression pattern of CR3, FcγRIII and FcɛRII on GCF PMNLs. However, C5a and IL-I failed to induce changes in FcγRIII and FcɛRII. The results indicate that GCF neutrophils are activated, present enhanced adhesion and a decreased IgG-binding ability which would reflect that they are at the terminal stage of activation, and that GCF contains a larger eosinophil fraction than in PB. Moreover, these GCF eosinophils appear to be activated.     

Conventional radiographic and computed tomographic findings in cases of fracture of the mandibular condylar process

A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury. The conventional radiologic examination consisted of panoramic radiography and lateral transcranial view of the fracture in the mouth-open and mouth-closed positions. Sixteen patients with 21 fractures of the condylar process were examined additionally by computed tomography (CT) because of temporomandibular joint problems in the sagittal and coronal projection. Computed tomography revealed bony changes in the fractured mandibular condyle and its position in the mandibular fossa more exactly than conventional radiographic examinations. Furthermore, the results showed that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, suggesting the more frequent use of CT examinations to evaluate temporomandibular joint changes after condylar process fractures.     

Influence of the chemical structure of functional monomers on their adhesive performance

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.     

Fatal subarachnoid haemorrhage associated with dental local anaesthesia

A case is described of sudden death occurring after the use of a noradrenaline-containing local anaesthetic. Autopsy revealed a massive subarachnoid haemorrhage following a ruptured cerebral aneurysm. The noradrenaline in the local anaesthetic is thought to be an important factor in the cause of the rupture. It is recommended that preparations containing 1:25,000 noradrenaline not be used.