The structures of the several functional monomers for base metal alloys as well as noble metal alloys and their mechanism for bonding to metal were explained, and then, adhesive prostheses applying metal bonding techniques were described in the current review. Generally speaking, functional monomer is composed of three parts：hydrophilic group which can bond to either metal oxide surface or metal surface itself, hydrophobic group which can copolymerize with methyl methacrylate monomer, and intermediate structure which is supposed to affect bond durability. The most well-known fixed prostheses utilizing metal bonding techniques are resin-bonded fixed partial dentures and overcastings. On the other hand, metal bonding techniques are also effective for fabrication or repair of removable prostheses. However, the bond durability cannot be preserved as much as fixed prostheses because of the much severe condition of removable prostheses.

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Orthognathic treatments are used in patients with jaw deformities to improve stomatognathic function and facial appearance. This review considered 27 articles reporting on subjects with jaw deformities in Japan. We considered reports from medical facilities and our database of patients with skeletal malocclusion in the Division of Orofacial Functions and Orthodontics, Kyushu Dental University. Results suggest that： 1. The total number of subjects had previously been increasing, but has plateaued in recent years. 2. There were previously more females than males, but the ratio of males has started to increase in recent years. 3. The mean age at surgery has risen. 4. The number of double jaw and maxillary surgeries has increased, but mandibular surgery has decreased. 5. The most common bone fixation technique after sagittal split ramus osteotomy has changed from wire to plate, through screw-fixation.

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This study was specifically designed to increase the number of chews to prevent lifestyle-related diseases, such as obesity. The study verified that eating smaller mouthful volumes increases the number of chews while eating food. Furthermore, the study confirmed that eating smaller mouthful volumes is associated with the formation of boluses appropriate in size for swallowing. Subsequently, Shiozawa et al. demonstrated that eating food with utensils, such as knives and forks, reduced the mouthful volume and increased the number of chews more than biting out chunks or whole pieces of food without using utensils. A questionnaire was developed to screen for patients who required behavioral modification for eating. 　It is important for future dental hygienists to gather studies as scientific evidence for the advice they provide to their patients. The research perspectives of these studies could demonstrate related trivial events in daily life.

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To determine whether aging influences the position of the leading edge of the bolus during chew swallow as identified using videofluorography (VF). Mastication time and number of chew cycles increase with age for solid foods. Entry of the bolus during chewing in the pharynx; this may affect the number of chew cycles and increasing age. For solid foods, the position of the leading edge of the bolus changed with increasing age, showing a tendency for the head of the bolus to easily reach the pharynx beyond the epiglottis before the initiation of swallowing in elderly persons. This tendency may result from a decreased sensitivity and increased reflex threshold in the pharyngeal area. This premature transition of the bolus into the pharynx and decreased sensitivity of the larynx may cause silent aspiration of food during chewing in elderly persons.

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