Nickel hypersensitivity is a common problem, especially among young females, with a prevalence of 5 to 10%, increasing to 30%. In comparison with the oral mucosa, skin is more sensitive to an allergic reaction. The oral mucosa is less sensitive to nickel due to the difference in anatomical structure and the presence of pellicle. Nickel is used in many orthodontic appliances. Due to corrosion nickel ions can be released into the oral cavity. The extent of the corrosion of the appliance depends on the pH, the composition of saliva and plaque, temperature and mechanical loading. In spite of the relatively high amount of nickel processed in orthodontic appliances nickel allergies are rare. In cases of nickel-hypersensitivity, nickel-free appliances should be used.

In order to make teeth-movement possible, orthodontic anchorage is necessary. Neighbouring teeth, a headgear, dental implants and bone anchors can be used. During the period 2002-2007 158 bone anchors have been placed in 84 patients by an oral surgeon after referral by an orthodontist in order to achieve anchorage for orthodontic treatment. The bone anchor consists of a titanium osteosynthesis-plate ending in a round neck perforating the soft tissue and a cylinder attached to it. The indications for placement, results and complications were registered. 15 anchors (9,5%) were lost prematurely and in 13 cases (8,2%) complications needing surgical intervention were reported. It is concluded that zygoma-bone anchor is a good alternative for orthodontic anchorage and the number of complications is acceptable, though there is room for improvement.

It is estimated that in the Netherlands over 100.000 children per year are victims of child abuse. In more than 50% of the cases of physical abuse there is a trauma of the head and neck area. Therefore, it is likely that (without realizing it) dentists are regularly confronted with cases of child abuse. Dentists have an ethical duty to take positive action in cases of suspected child abuse. They may refer the patient to an oral surgeon, consult the family physician or ask the advice of the ‘Advies- en Meldpunt Kindermishandeling’ (Advice and Report Centre for Child Abuse). The Dutch Dental Association, the Dutch Association of Family Physicians and the Royal College of Physiotherapists have signed a formal agreement to promote closer cooperation in identifying child abuse more quickly.

Dental implantology represents an essential step in the rehabilitation of function, stability and aesthetics of the human dentition. The introduction of dental implantology has at the same time created a problem: peri-implant infections. Putative risk factors for this disorder are, among others, smoking, a history of periodontitis, genetic traits, and uncontrolled diabetes mellitus. Since no validated protocol for the treatment of peri-implantitis exists, clinicians have to rely on their own experience and knowledge and on the experience of others.

A 49-year-old woman was referred to an oral and maxillofacial surgeon by her family dentist because of severe periodontal disease in the maxilla. Their request was to estimate the feasibility of reconstruction using implants, after the removal of all maxillary teeth. A new method of treatment which makes use of computer tomography, virtual implant planning and a customized surgical template was applied. With the benefit of this method, 4 implants were inserted without bone augmentation, on which a previously constructed superstructure was placed during the same treatment session. This treatment concept makes optimal use of the bone volume available. Additional advantages are the possibility of flapless transmucosal immediate implant insertion and the possibility of immediately placing the superstructure. However, inaccuracies during implant planning and surgical treatment can easily lead to a poor fitting superstructure. Moreover, determining primary implant stability during treatment is difficult.

Primary brain tumours are relatively rare, but brain metastases are a frequent complication of the most common cancers elsewhere in the body (breast, lung, melanoma). Loss of function and excitation of brain nerves i.e. sensory loss, paralysis and pain in the head-and-neck region are specific features in base of skull tumours: meningioma, glomus tumours, vestibular Schwannoma, meningeal metastases by breast cancer, melanoma, and leukaemia, melanoma. In the diagnosis and treatment of brain tumours, special attention is required for rare complications in the head and neck region.