[The preprosthetic treatment focusing on single- or multi-unit fixed dental prostheses]. / De voorbereidende behandeling voor een behandeling met kronen en bruggen.

The preprosthetic treatment is a phase of the so-called patient-centred oral healthcare cycle. The goal of the preprosthetic treatment is the elimination of pathological conditions and of uncertainties and risks to the greatest extent possible. Teeth in a reduced occlusal system can be distinguished functionally as strategic, non-strategic, and undesirable. The most important objective of the preprosthetic treatment is to establish a positive prognosis for the strategic teeth. Specific aspects relevant to the preprosthetic treatment are: referral to a specialist, requesting a second opinion, inserting 1 or more oral implants, transitional treatments, and occlusal adjustments. Subsequently, the preprosthetic treatment is evaluated to assess whether healthy circumstances have been established for the intended treatment with single- or multi-unit fixed dental prostheses.

[Single and multi-teeth fixed prostheses--functions and types]. / Kronen en bruggen-- functies en typen.

A single fixed prosthesis replaces parts of a tooth. However, a single fixed prosthesis may also be implant supported and in such a case it replaces in combination with the oral implant an entire tooth. A multi-teeth fixed prosthesis replaces 1 or more teeth using pontics and can be fixed on teeth, oral implants, or both. Materials applied are metal, metal fused with porcelain, and ceramic. After indicating a fixed prosthesis, the intended function is determining the appropriate type. Intended functions of single fixed prosthesis are: improvement of aesthetics, limitation of tooth fracture, acting as an abutment tooth for a removable metal frame partial denture, and splinting of mobile teeth. In addition, single fixed prostheses may be characterized by the number of replaced tooth surfaces and by the peripheral extension of the tooth preparation. The intended functions of a multi-teeth fixed prosthesis are improvement of aesthetics, chewing function, and occlusal as well as mandibular stability. Specific types of fixed prosthesis are used as temporary restorations and in case of evaluating preliminary treatments preceding a final treatment.

[Medico-ethical considerations when indicating single-tooth fixed prosthesis, multi-teeth fixed prosthesis, and oral implants]. / Medisch-ethische overwegingen bij de indicatie van kronen, bruggen en implantaten.

The question whether a patient needs extensive and invasive treatment, such as single-tooth fixed prosthesis, multi-teeth fixed prosthesis or oral implants, can be established only in a dialogue with mutual respect between the healthcare provider and the patient. With respect to this question, the following principles have to be considered: the patient's autonomy, beneficence, non-maleficence, and justice. These principles are reflected in legislation and are implicitly applied in complaint and disciplinary jurisdiction. When the autonomy of a patient is not sufficiently respected by a healthcare provider, a patient complaint might be the result, such as a complaint of impertinent treatment, lack of informed consent, or poor patient documentation. If beneficence or non-maleficence principles are violated, an intrinsic treatment complaint might be the result, such as a complaint of inadequate treatment planning, often based on inadequate examination, and complications or untimely failure of single-tooth fixed prosthesis, multi-teeth fixed prosthesis or oral implants. Respecting the previously mentioned principles promotes appropriate healthcare to the patient also in complex care with other healthcare providers.

[Extension of (extremely) shortened dental arches by fixed or removable partial dentures]. / Verlenging van (extreem) verkorte tandbogen met vaste of uitneembare prothetische constructies.

Whether a shortened dental arch needs to be extended depends on the degree of the shortening. Four categories of shortened dental arches can be distinguished: 1. slightly shortened dental arches; 2. moderately shortened dental arches; 3. extremely shortened dental arches; and 4. asymmetrical extremely shortened dental arches. Decision-making on extending a shortened dental arch should be based on oral function and the patient's perceived impact on oral health-related quality of life. According to this principle, there is no evidence for extending slightly shortened dental arches. Extending moderately shortened dental arches is indicated in exceptional cases, especially for aesthetic reasons. In the case of (asymmetrical) extremely shortened dental arches there are reasons for extension. The extension can be restricted to restoring the arch to the level of a moderately shortened dental arch. With this treatment strategy, it is possible in many cases to conform to the current trend of using fixed partial dentures rather than removable partial dentures.

Direct recording of EDP-EDV relationship in isolated rat left ventricle: effect of diastolic crossbridge formation.

OBJECTIVE: The aim was to investigate whether the end diastolic pressure-end diastolic volume (EDP-EDV) relationship of the left ventricle can be influenced by calcium dependent elements, especially at low values of end diastolic pressure. METHODS: Isolated rat hearts were perfused in a modified Langendorff perfusion system. The EDP-EDV relationship of the left ventricle was investigated. Pressure was recorded with a microtip pressure catheter and volume with a microconductance catheter. Crossbridge cycling was affected by adding calcium antagonists (verapamil, diltiazem, nifedipine at 2.10(-7) M) or by adding the Mg-ATPase blocker BDM (2,3-butanedione-2-monoxime, 10(-3) M) to the perfusate. RESULTS: The above had a negative inotropic effect in systole. At EDP = 0 after stimulation the active isovolumetric pressure was zero. In diastole, BDM shifted the EDP-EDV relationship to slightly smaller EDVs. A decrease of about 5% in the EDV was found at lower EDP values. Ca2+ antagonists increased the EDV up to 40-80% at low EDP values. At higher EDP values only a small increase of EDV (about 10%) was found after verapamil perfusion. The results obtained are interpreted in terms of a three step crossbridge model. CONCLUSIONS: At low EDP, diastolic volume is dependent upon weakly bound crossbridges as a function of the [Ca2+] in the cardiac cell.