Tandlaegebladet最新文献

The potential for in-depth cure of the light-activated resin cement TULUX-CEM was investigated. Disks of TULUX-CEM were irradiated through a layer of inlay/onlay material of varying thickness. After the irradiation, the hardness of the disks was measured. It was found that the resin cement became softer as the thickness of overlying inlay/onlay material increased from 2.0 to 3.5 mm. At a thickness of 4.0 mm, the resin cement remained unpolymerized. It was concluded that in certain situations the in-depth cure of resin cements activated only by light may not be sufficient.

Measurements of fracture strengths of incisors from sheep, previously fractured and then restored by reattaching the fragments with a light-curable resin, revealed that pretreatment of the fracture surfaces with dentin bonding agents such as Gluma, Tenure or Scotchbond2 and acid-etching of the enamel, gave values of about half the fracture strength of intact teeth. Measurements furthermore demonstrated that pretreatment by a combination of dentin bonding agents and acid-etching of the enamel yielded higher fracture strengths of the restored teeth, than that of teeth restored using only one of the two pretreatments. Fractured incisors, restored by Gluma-treatment of the dentin, acid-etching of the enamel and fragment-bonding with a light-curable resin, were further restored with porcelain veneers after preparation. Fracture strength measurements of such restored teeth revealed strength not significantly different from that of intact teeth. It is suggested that such restorations, could have a reasonably long period of function clinically.

This investigation measured the effect of polyacrylic acid treatment of dentin on adhesion of glass ionomer cement. The dentin was ground on paper No. 220 or No. 500 and treated with a polyacrylic acid solution of 10% or 25% for either 10 s or 30 s. The differences observed in the scanning electron microscope between the differently treated dentin surfaces were not reflected in the bond strength results. Only differences in surface texture due to different coarseness of grinding influenced the adhesion. As to specimens ground on paper No. 220, pretreatment with polyacrylic acid enhanced adhesion of glass ionomer cement. No effect of polyacrylic acid was found on bonding between glass ionomer cement and dentin ground on paper No. 500.

The purpose of this review is to evaluate our present knowledge of fluoride effect on bone formation on basis of the literature. It is likely that fluoride affects the remodelling processes of the skeleton as well as growth related bone formation. During bone remodelling the amount of bone and osteoid tissue is increased by alteration of the balance between resorption and formation. This finding may be accompagnied by impaired mineralization. In studies of fluoride effect on growth related bone formation a number of quantitative histologic alterations have been observed. These include reduction in epiphyseal plate thickness and changes in cellular morphology as well as a retardation of mineralization. The pathogenetic mechanisms behind the observed effects and the variation in tissue response are still unexplained. Fluoride may have a direct cellular effect causing disturbances in cell morphology and metabolism, but the effects may also involve local supracellular mechanisms as well as the general homeostasis of the individual.

Diagnostic arthroscopy and arthroscopic surgery of the TMJ has during the recent years been introduced in the treatment of internal derangements, preauricular pain and osteoarthrosis of the TMJ. In closed lock cases and in cases with preauricular pain a satisfactory result of treatment has been described in 80-90% of cases, where there was lacking effect of conservative treatment with splints and physiotherapy. The refinement in the technique has made it possible to use rotating instruments, cauterisation and to perform suturing through the arthroscopic cannula and in this way reduce the need for open joint surgery. Due to the technique only few complications have been reported. In the Department of Oral and Maxillofacial Surgery in the University Hospital of Aarhus arthroscopy of the TMJ was introduced 1 1/2 year ago and 22 patients with the clinical diagnosis closed lock or preauricular pain or a combination of these has been treated during this period. The results are satisfactory in most cases and are comparable with previously published results.

This paper reviews the clinical use of titanium miniplate osteosynthesis in maxillofacial traumatology and orthognathic surgery. These materials were originally developed for treatment of mandibular fractures, but the application has within recent years been extended to other fractures of the facial skeleton and orthognathic surgery. The osteosynthesis increase stability in many situations, and may reduce or eliminate the need for post-operative intermaxillary fixation, by which morbidity, hospitalization period and period of sick-leave can be reduced. In orthognathic surgery, the stability of the miniplate osteosynthesis increase the demand for precision during surgery as compared to conventional fixation with wire osteosynthesis and intermaxillary fixation. Further refinements of the technique are, however, necessary in the future, as the current techniques does not always allow a sufficient reproduction of the position of the condylar segment.

The present paper discuss the development of osteoradionecrosis (ORN) in the jaws. ORN is the end stage of tissue injury induced by irradiation. The most prominent etiologic factor of ORN seems to be the effect of radiation on endothelial cells lining the vessels. These cells are, as tumor cells, highly radiosensitive, and radiation leads to a vascular damage resulting in hypoxic, hypovascular and hypocellular tissues. Wound healing in such tissues is impaired since nutritional demands of the wound, including oxygen, cannot be supplied due to the degenerative changes in the blood vessels. The paper furthermore describes the scientific basis for the use of hyperbaric oxygen therapy (HBO) in ORN. HBO increase the vascularity in the tissues injured by radiation, and thus tissue viability and healing capacity is increased reducing the risk for spontaneous or traumainduced ORN. Protocols for the treatment of patients with ORN are presented and prophylactic guidelines are described.