[Wish fulfilling medicine and wish fulfilling dentistry: legal aspects]. / Wensgeneeskunde en wenstandheelkunde: juridische aspecten.

Wish fulfilling medicine (human enhancement (therapy)) concerns medical treatment without a direct medical need. In traditional medicine, a classical triad applies: 1. after investigation symptoms of illness lead to 2. a diagnosis, followed by 3. a proposal for treatment by the health care provider. In wish fulfilling medicine, the emphasis lies on patient's wishes. Wish fulfilling medicine concerns medical treatment, often at the request of the patient, and should be distinguished from shared decision-making,a form of communication seeking to meet the preferences of the patient and to actively involve the patient in his treatment. In the Netherlands, in accordance with the Healthcare Quality, Complaints and Disputes Act, health care providers have to offer good care at a good level, which is safe, effective, efficient and client-orientated, offered in a timely fashion and geared to the real needs of the client. Good care has to meet professional standards. In this way, fulfilling patients' wishes for treatment without a medical need can be restricted by law.

[Wish fulfilling medicine and wish fulfilling dentistry: -medical-ethical aspects]. / Wensgeneeskunde en wenstandheel­kunde: medisch-ethische aspecten.

Wish fulfilling medicine comprises medical procedures applied without a direct medical need. In such procedures, the medical-ethical principles can come under pressure: the autonomy of the patient, when wishes originate from social pressure; beneficence when the (underlying) aim and consequences are unclear; and 'doing no harm', when that appears to be impossible. The principle of justice, too, could come under threat when especially those with a privileged socio-economic background can take advantage of wish fulfilling medicine. Regardless of whether it concerns wish fulfilling medicine or conventional medicine, respect for human dignity and the individual integrity of the patient continue to be paramount. In care ethics and moral ethics, the qualities necessary in a proper caregiver are emphasised, such as caring, compassion, commitment, honesty and personal dedication. Wish fulfilling medicine is the subject of significant ethical debate. Important aspects arising from this debate are that the risks of harm should be limited, human dignity and integrity should be respected, people should genuinely be helped and the principle of justice should be upheld.

[Wish fulfilling medicine and wish fulfilling dentistry: what does this mean?] / Wensgeneeskunde en wens­tandheelkunde: wat wordt ermee bedoeld?

Wish fulfilling medicine refers to medical procedures applied without a direct medical need. In wish fulfilling medicine, the wish of the patient is dominant, but wish fulfilling medicine is also promoted indirectly by healthcare providers, (pharmaceutical) companies and healthcare insurers. Wish fulfilling medicine often concerns the enhancement of appearance or performance; therefore, wish fulfilling medicine is also referred to as (human) enhancement (therapy). The line between traditional and wish fulfilling medicine is vague: the border between illness and health, normal and abnormal functioning is not sharply defined and is relative to time and place. In the Netherlands, wish fulfilling medicine is not covered in the basic package provided by healthcare insurers and is paid for by the patients themselves. However, 'pay yourself' is not a decisive criterion for wish fulfilling medicine. With new biotechnological developments the domain of wish fulfilling medicine is expanding. Some dental treatments can be considered as wish fulfilling dentistry, for example in the context of cosmetic dentistry, orthodontics, or dental implantology. Although wish fulfilling medical treatments do not cure disease, they can promote health.

[Technical aspects of treatments with single- and multi-unit fixed dental prostheses]. / Tandtechnische aspecten van de vervaardiging van kronen en bruggen.

For the manufacture of single- and multi-unit fixed dental prostheses, effective communication between dentist and dental technician is required. Mutual insight concerning the (im)possibilities of available treatments and technical options is prerequisitefor this communication. The manufacture of single- and multi-unit fixed dental prostheses involves 4 phases: recording the required detailed information on the relevant teeth and the occlusal system, the technical adjustments, the technical design and the technical fabrication. These phases can be accomplished through an analogue or (semi)digital procedure. Pioneering developments are computer aided design and computer aided manufacturing (CAD/CAM), and computerised milling machines. Associated with this are 3 manufacturing methods which can be distinguished: the dental practice method, the dental laboratory method and the milling centre method. Materials applied are metal alloys and ceramics, while resins are used for provisional and transitional constructions. Due to the fact that the choice of material in the analogue procedure is limited, CAD/CAM offers more options, the digital procedure is expected to gain ground gradually. It is expected that this development will provide an impulse to higher quality.

[Loading and strength of single- and multi-unit fixed dental prostheses 2. Strength]. / Op kronen en bruggen uitgeoefende krachten en het weerstaan daarvan 2. Mechanische belastbaarheid.

The ultimate strength of a dental prosthesis is defined as the strongest loading force applied to the prosthesis until afracture failure occurs. Important key terms are strength, hardness, toughness and fatigue. Relatively prevalent complications of single- and multi-unit fixed dental prostheses are porcelain and ceramic fractures. Afactor which also plays a role is the functional loading force from the entire orofacial system. With respect to the strength of multi-unit fixed dental prostheses, the length of the arch span between the abutment teeth, the pontic with the connectors and the possible cantilevers are the critical components. Components of the configuration ofabutment teeth of single- and multi-unit fixed dental prostheses which are relevant for its strength are the convergence angle and the design of(the area above) the (cervical) outline. Finally, the thickness of the porcelain or the ceramic (veneers) ofmetal-ceramic and all-ceramic single- and multi-unit fixed dental prostheses is of importance.

[Loading and strength of single- and multi-unit fixed dental prostheses. 1. Retention and resistance]. / Op kronen en bruggen uitgeoefende krachten en het weerstaan daarvan. 1. Retentie en resistentie.

The degree to which single- and multi-unit fixed dental prostheses are able to withstand loading forces is dependent, among other things, on the quality of their retention and resistance. The quality of the retention and resistance of the configuration of an abutment tooth prepared for a metal and metal-ceramic single-unit fixed dental prosthesis is determined by the configuration's convergence angle, the height, the volume, the interocclusal space, the cervical outline design, the additional preparations, the quality of the (build-up) restoration, and the surface roughness. A silicate ceramic single-unit fixed dental prosthesis is attached through adhesion using a composite cement, but the retention and resistance of an oxide ceramic single-unit fixed dental prosthesis is dependent on the abutment tooth configuration. Most types of multi-unit fixed dental prosthesis have the following additional retention and resistance determining factors: the position in the occlusal system, the number of abutment teeth and their mutual configurations, and the length of (cantilever) pontics. A resin-bonded fixed partial denture's retention and resistance are determined by its bonding as well as its enamel surface coverage and its resistance preparations.

[Prosthetic replacement of missing teeth. Indications for fixed and removable dental prostheses]. / Prothetische vervanging van afwezige gebitselementen. Indicaties voor vaste en uitneembare prothetische constructies.

Prosthetic replacement of missing teeth aims to improve health. This can be achieved by improving the patient's well-being and quality of life and by restoring the biological balance in terms ofocclusal and mandibular stability in the occlusal and the orofacial system. In occlusal systems with a complete anterior region and 'satisfactory' premolar and molar regions, prosthetic replacement of missing teeth is not indicated generally. In case ofa restricted number of missing teeth in the anterior region and/or a not 'satisfactory' premolar region, fixed dental prostheses may be indicated. In case of an incomplete anterior region and no 'satisfactory'premolar as well as molar regions, removable dental prostheses are usually indicated. These guidelines are presented in the absence of sufficient scientific evidence. Therefore, in clinical decision making, the question whether prosthetic replacement of missing teeth is sensible, and if so, by which type of dental prosthesis, can only be answered after a dialogue with mutual respect between care provider and patient.

Occlusal tooth wear in Chinese adults with shortened dental arches.

To assess associations between occlusal tooth wear and shortened dental arches (SDA) in Chinese 40 years and older subjects. From a sample of 1462 urban and rural adults, those presenting with SDA (n = 150) were compared with a control group of 65 randomly selected subjects with complete dentitions (CDA). Occlusal wear was assessed using a modified Smith and Knight index - the occlusal tooth wear index (OWTI) - and analysed using multivariate (logistic) regression. There was no significant effect from SDA on severe occlusal wear (OTWI score 3 or 4: OR = 2.016; 95% CI = 0.960-4.231; P = 0.064). Higher age was associated with severe occlusal wear (P values ≤0.007) and with higher mean OTWI scores; urban had less often severe occlusal wear than rural residents (OR = 0.519; P = 0.008). Higher mean OTWI scores were associated with rural residents, except for anterior teeth. Females had lower mean OTWI score for anterior teeth (effect = -0.153; P = 0.030). Premolars in SDA had higher mean OTWI scores compared with those in CDA (effect = +0.213; P = 0.006). In SDA, more posterior occluding pairs (POPs) were associated with lower mean OTWI sores for anterior teeth (effect: -0.158; P = 0.008) and higher scores for molars (effect: +0.249, P = 0.003). Subjects with SDA or CDA presented comparable occlusal wear, but premolars in SDA tend to have higher probability for having occlusal wear. Fewer numbers of POPs were associated with more wear in anterior teeth.

[Determining and recording maxillomandibular relationships for the fabrication of single-unit and multi-unit fixed dental prostheses]. / Bepaling en registratie van de maxillomandibulaire relatie bij de vervaardiging van kronen en bruggen.

In a correctly functioning occlusal system, the design of the occlusal parts of single-unit and multi-unit fixed dental prostheses is generally determined by the maximum intercuspation. Determining and recording the maxillomandibular relationships is only required in case the adjacent teeth do not offer adequate support or reference to put the maxillary and mandibular cast in maximum intercuspation or in case the existing occlusion needs a well-structured alteration. The maxillomandibular relationships can be determined and registered analogously and digitally and on that basis the maxillary and mandibular casts can be mounted in a (virtual) occludator or articulator. In the absence of a distinct occlusal plane, one may consider first carrying out a facebow recording and transfer. Usually, the accuracy of determining and recording the maxillomandibular relationships does not increase when using more complicated methods.

[Aftercare for durability and profitability of single-unit and multi-unit fixed dental prostheses]. / Nazorg voor dutrzaamheid en profijtelijkheid van kronen en bruggen.

An important aim ofa treatment with single-unit and multi-unit fixed dental prostheses is a durable and profitable treatment outcome. That requires aftercare, too. First, the frequency of routine oral examinations should be assessed, using an individual risk profile. The objectives of the routine oral examinations are the prevention and, when necessary, the treatment of pathological conditions and complications. With regard to prevention, attention should be paid to information and instruction, oral biofilm and calculus, non-functional activities, hard tooth tissues, periodontal and peri-implant tissues, and saliva. Subsequently, it can be determined whether the intended durability and profitability have been achieved or can still be achieved, whether or not through indicated adjustments. Special attention should be paid to endodontically treated teeth. Restorative, repair or replacement treatments may be indicated in case ofcomplications, such as loose single- or multi-unitfixed dental prosthesis, fracture of a fixed dental prosthesis unit, lost tooth pulp vitality, tooth root fracture, and implant or implant abutment problems.

[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.

[Implant-supported single- and multi-unit fixed dental prostheses in periodontally compromised patients]. / Implantaatgedragen kronen en bruggen bij parodontaal gecompromitteerde patiënten.

As a result of the introduction of oral implants, it is also possible to treat patients who have a reduced occlusal system with implant-supported fixed dental prostheses. Many publications report the successful application of implant-supported single- and multi-unit fixed dental prostheses. However, it is questionable if implants are also successful in periodontally compromised patients. With respect to implant treatment, roughly 3 categories of periodontally compromised patients can be distinguished: patients who have not been treated for periodontitis, patients who have been treated for periodontitis and have stable periodontal health, and those who have been treated but have not achieved stable periodontal health. For the first group, periodontal treatment is required. Inserting implants is only indicated in cases showing steady improvement of post-operative periodontal health. The second category has no contraindication for inserting implants. For the third group, inserting implants is contraindicated absolutely. When treatment with oral implants is indicated, meticulous aftercare and a surgical treatment which enables adequate oral hygiene self-care are strict requirements.

[Build-up restorations after extensive loss of tooth tissue]. / Funderings restauraties bij uitgebreid weefselverlies van gebitselementen.

After (extensive) loss of tooth tissue, vital teeth can be built up completely with composite restoration material. Sometimes, the application of additional retentive preparations is indicated. In exceptional cases, a root canal treatment is indicated, following which a root canal post is applied if necessary. Endodontically treated multi-rooted teeth can be built up entirely with composite, utilizing the pulp chamber and root canal accesses for retention. However, in single-rooted teeth a root canal post is necessary, in which case a prefabricated root post is used. Traditionally, metal posts were used in combination with a cast, indirect build-up restoration. Subsequently, directly fabricated cores, combining metal posts with amalgam or, at the present time, composite restoration material, became customary. The present trend is to use prefabricated or individually fabricated fibre-reinforced posts. After restoring a tooth with a build-up restoration, a combined build-up restoration can be chosen, or a direct or indirect crown single tooth prosthesis.

[Single- and multi-unit fixed dental prostheses in relation to the occlusal system]. / Kronen en bruggen in relatie tot het occlusiesysteem.

Occlusion concepts based on functional aspects offer more solid ground in the diagnostic process and in the treatment of (reduced) dentitions than morphologically and mechanically oriented occlusion concepts. Nevertheless, for occlusal reconstruction morphologically oriented guidelines are necessary. These guidelines are based on the border movements and positions of the mandible in the orofacial system, and on the location and modelling of the occlusal contacts in the occlusal system. The modelling of single- and multi-unit fixed dental prostheses must harmonize with the occlusal system. Moreover, an important feature is the relation of the anterior teeth which enables mutually protected occlusion. Characteristics of a healthy orofacial and occlusal system are: absence of pathology, perceived sufficient oral functions, variability inform and function, and adaptive capacity. When designing single- or multiunit fixed dental prostheses, a pragmatic starting point is to maintain the existing occlusion and the existing speech pattern unless arguments can be provided for alterations. The occlusal design should aim at optimizing oral functions, such as mandibular and occlusal stability.

[The role of single- and multiple-unit fixed dental prostheses in the strength distribution of the occlusal and orofacial system]. / Het krachtenspel van kronen en bruggen in het occlusiesystem, mede in relatie tot het orofaciale systeem.

An occlusal system that does not function well, has a negative impact on the functional level of the oral system and the orofacial system. In purely mechanical terms, a limited anatomical reduction of the occlusal system has limited implications for the functional level since the occlusal system has several forms of adaptation, reserve, and compensation. However, following the loss of (parts of) teeth, an occlusal system may be anatomically reduced to such an extent that restoration of the functional level is required, for instance by the use of implant-supported single- and multiple-unit fixed dental prostheses. The mechanical strength of a tooth and a single-tooth fixed dental prosthesis on a similar tooth type is not essentially different. But the same cannot be said of the mechanical strength of a multiple-unit fixed dental prosthesis, because the strength is controlled by the mechanoreceptors in the periodontal ligaments of the abutment teeth. This control system is disturbed by the insufficiency of or, when oral implants are involved, the absence of mechano-receptors. It is unknown whether this is causing noticeable problems.

Swallowing threshold parameters of subjects with shortened dental arches.

OBJECTIVES: To quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA). METHODS: Fourteen females with SDA (3-4 occlusal premolar units) and 14 females with CDA were instructed to chew silicone test 'food' (cubic particles with a total volume of 3 cm(3)). They spit it out the moment they felt the urge to swallow and the pulverized particles were collected. Swallowing threshold parameters were number of chewing cycles, time until 'swallowing', and median particle size of the pulverized particles as determined by sieving the food. Chewing tests were performed twice and outcomes were averaged. RESULTS: The number of chewing cycles until 'swallowing' of subjects with SDA was approximately 1.7 times (p<0.005) that of the controls and this took approximately 1.6 times more time (p<0.01). The median particle size until 'swallowing' did not differ significantly between the groups, but demonstrated large individual differences. Regression analyses indicated that the ratio of median particle size until 'swallowing' of SDA and CDA becomes progressively unfavourable for SDA with increasing numbers of chewing cycles. CONCLUSIONS: Subjects with SDA pulverized test 'food' particles to sizes comparable to subjects with CDA, but chewed longer with more chewing cycles until 'swallowing'. Higher numbers of chewing cycles were associated with increasing difference between SDA and CDA regarding the median particle size until 'swallowing'. CLINICAL SIGNIFICANCE: Compared to subjects with CDA, subjects with moderate SDA pulverize test food particles to comparable size by chewing longer before "swallowing". Therefore, overloading the digestive system by swallowing courser food particles is unlikely in SDA. Consequently, replacement of absent molars just to optimize chewing function is not advised.

[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.

[Developing a plan of treatment with a cast metal frame removable partial denture]. / Het opstellen van een behandelplan voor een frameprothese.

When considering prosthetic replacement of absent teeth, a treatment plan is necessary. In evaluating whether replacement of teeth is sensible, the causes and consequences of tooth loss must be considered. This concerns information about problems having to do with the patient, potential complications, purely prosthodontic problems, and specific problems. The patient-related problems require collecting data through patient history as well as a clinical and radiologic examination. Complications are risk-factors which negatively influence the prognosis of general health or of a treatment. Potential complications should be eliminated as much as possible through a preliminary treatment. Purely prosthodontic problems are conditions in the area of absence of several teeth or parts of them, and in the area of occlusal and mandibular stability and articulation. Specific problems may be related to inadequate interocclusal space and the quality of the abutment teeth. A cast metal frame removable partial denture may be a relatively inexpensive and minimally treatment alternative for an expensive and complicated treatment with 1 or more fixed partial dentures.

[(Semi-)precision attachments for cast metal frame removable partial dentures]. / (Semi)precisieverankering bij frameprothesen.

When compared to a conventional attachment, a (semi)precision attachment for a cast metal frame removable partial denture can perform a number of functions better. Proper assessment of the condition of the abutment teeth is needed for an adequate indication. Selecting the type of (semi-)precision attachment is primarily determined by the available maxillomandibular space, the crown length as well as the possibility of adequate oral self-care. With regard to technical characteristics, (semi-)precision attachments are classified according to measures of freedom. The distinct types are cast intra- and extra-coronal, adhesive and overdenture (semi-)precision attachments. With the lapse of time, some wear of the different parts of an attachment may occur, requiring specific subsequent care. Whether or not in combination with oral implants, (semi-)precision attachments often offer patients improved self-confidence and self-image. However, the relatively high cost is a barrier to apply (semi-)precision attachments widely.