No consensus has been obtained regarding the choice of implant-supported prosthesis for maxillary edentulous jaws up to the present. Judging from the clinical evidence, the following two treatment modalities are generally recommended for maxillary edentulous jaws: (1) bone-anchored bridge with 4 or more implants connected, (2) implant-supported overdenture (IOD) with 4 or more implants connected. In terms of the selection of both implant-supported prostheses, following factors should be considered; the risk of implant loss, mechanical troubles of superstructure, and psychological burden of using removable prostheses. Considering these factors, a treatment plan should be made with a bone-anchored bridge as the first choice. If the implant placement site has sufficient width and height of bone, treatment with IOD can be selected in cases where lip support is required, anterior crossbite is observed, or in cases where the patient has financial constraints.

The implant approach to the maxillary edentulous jaw comprises fixed prosthesis and removable prosthesis [removable implant overdenture (IOD)]. We held a debate on the choice of the prosthesis in clinical practice on the side of IOD. In the debate, it was important to preliminarily decide on the design that should be used, and therefore rigid and flexible IODs were discussed separately. Since various factors should be taken into account, the study was conducted in groups of items, i.e., anatomical aspects and preoperative conditions such as denture use before surgery, treatment costs, and life stage, especially in view of the necessity of nursing care. IOD was considered to be more appropriate than fixed prosthesis when taking the following conditions into account: if the horizontal ridge absorption in patients had progressed, when dentures familiar to patients had been used before implantation, when treatment costs would be reduced, or when patients’ nursing care needs would be expected. IODs seemed to fulfill implant prostheses’ requirements for patients with maxillary edentulous jaw in the aged society.

30 years have passed since the start of the my practice, “I will take care of the patients for the rest of their life” But now I understand that “life” is my life, not a patient’s life. Some of the elderly patients who have come to my practice for a long time may not able to come. So I can not take care of them until their end of life. In a super-aged society It is noted that to maintain oral function leads to the extension of the healthy life span. There are many elderly people who need dental treatment even if they can not go to the dental clinic, and they are required to be involved as a home dentist until the end of life. I would like to consider what is required in the super-aged society as a home dentist.

Prosthetic-driven implant therapy is a concept based on the number of implants used, selections of implant position and surgical modalities, and so on, for functional and esthetic outcomes harmonized with stomatognathic system. This multidisciplinary concept requires the aggregation of preoperative treatment, surgery, designing of prosthesis and postoperative maintenance at a very high level. Multidisciplinary treatment in the field of medicine is performed by the aggregated doctors from many disciplines but in dentistry it is often done by one dentist. In the present manuscript, we would like to summarize the concept of multidiscipline for the successful prosthetic-driven implant therapy.

Nosocomial infection control is one of important problems to address in medical institutions. One of characteristics in dental practice is easy to be polluted around dental units and on the surface of equipment by infectious materials because of spreading considerable saliva or blood droplet associated with use of dental rotary cutting instrument. In Ministry of Health, Labour and Welfare, we disseminate by means of formulation the guideline for nosocomial infection control in dental practice and the infection control training sessions for dental professional.

I would like to mention nosocomial infection control in dental practice from view point of dental public health administration.

Several press reports on sterilization of dental handpieces and on dental unit waterlines have prompted the industry to review and renew the notion of how the infection prevention in dental practices should be.

This summary paper clarifies the concept of infection prevention based on existing guidelines and the administrative notifications issued. Also covered are the countermeasures of infection prevention adopted by manufacturers on such equipment as:

•Dental handpiece; where the mechanism of air-sucking phenomenon (“suck-back”), which often occurs with air turbine when it stops rotating, is explained while the solutions to it are also illustrated. Sterilization of handpieces using the autoclave is detailed here, too.

•Dental unit; where this paper covers the items ranging from the introduction of the water quality stipulation in Japan, the effectiveness and tips of “flushing” —analyzed using the data accumulated from the market research done by Japan Dental Machine Manufacturers Association— to the countermeasures offered by the manufacturers.

Purpose: The purpose of this study was to analyze the possibility of applying ultra-high-speed MRI to the temporomandibular joint region to clarify the movement of mandibular condyles and articular discs during mastication and quantify the distances of movement.

Materials and Methods: The subject was one male dentist who had completely dentulous jaws without any dental problem. Ultra-high-speed MRI of the subject’s temporomandibular joint region was taken during habitual opening and closing movements as a control and during movement when masticating gum and kamaboko as tests. The DICOM data was transferred to a DICOM viewer, from which the movement of the mandibular condyles and articular discs was observed and distances were quantified.

Discussion: The ultra-high-speed MRI yielded conventional information regarding the morphology and habitual opening and closing movement of the temporomandibular joints, as well as the masticatory movement of the mandibular condyles and articular discs. As a result, the movement distances of the condyles and discs could be quantified, which were found to be small values, during mastication.

Conclusion: Ultra-high-speed MRI can take many photographs consecutively. By applying it to the temporomandibular joints, it can reveal the masticatory movement of the mandibular condyles and articular discs and enable quantification of the movement distances.

Patient: A 61-year-old man suffered from chewing and swallowing difficulties. His jaws were edentulous and the right half side of the tongue was reconstructed with a transplanted flap after removal of a cancer, and its mobility was restricted. As a result of the assessment, the case was diagnosed as masticatory dysfunction and dysphagia caused by tongue movement disorder and poorly fitted dentures associated with surgery to remove the tongue cancer. As the final prostheses, an upper complete denture with the shape of a palatal augmentation prosthesis and a lower complete denture were provided.

Discussion: It is considered that a good prognosis was achieved by functionally harmonizing the denture form with the tongue and the perioral muscles, such as by using piezography for taking impressions of the denture space.

Conclusion: In postoperative cases of tongue cancer, making functionally coordinated dentures is useful for reconstructing function after surgery.

Patient: A 70-year-old woman was referred by the Oral Surgery Department to the Clinic for Maxillofacial Prosthetics to fabricate a surgical obturator. After tumor resection, an immediate surgical obturator was inserted and adjusted. Four months later, an interim obturator was inserted. As the soft tissue changed the obturator was adjusted frequently. A definitive obturator was inserted one year later. The perforation was closed, and she is in good condition using the obturator more than five years later.

Discussion: She could speak well with the surgical obturator. The interim obturator remained fitted regardless of the changes in soft tissue on the defect site. Collaboration with the surgeon enabled early rehabilitation of the patient. Regular checks and frequent adjustment of the obturator enabled it to keep up with the changes in soft tissue.

Conclusion: A maxillectomy patient was rehabilitated from an early stage using three obturators and satisfactory progress was made despite the changes of soft tissue.

Case overview: An 89-year-old woman was admitted to our clinic complaining of maladaptation of her dentures and poor esthetics following right maxillary gingival tumor resection. Lip support and the impression area were determined by adjusting her treatment dentures. The shape of the denture flange and arrangement of the artificial teeth were determined by the neutral zone, and new dentures were subsequently fabricated and inserted.

Discussion: To ensure stability during function, the new upper dentures were designed based on the shape of the treatment dentures and the neutral zone. Furthermore, artificial teeth were adjusted to decrease the lateral force during occlusion. We believe that the patient was satisfied with the treatment due to our having carefully considered both the esthetic design of the dentures and occlusion.

Conclusion: The prosthesis for defective jaw with adjustment of the shape after operation improved the patient’s QOL.

Patient: A 73-year-old female patient complained of masticatory disturbance due to instability and poor retention of a mandibular removable partial denture. Restoration with crowns and removable partial dentures improved the patient’s masticatory and esthetic disturbances, as well as oral health-related QOL.

Discussion: In recent years, the relationship between occlusal support and equilibrium function of the body has been reported. In this case, the patient’s masticatory disturbance was improved by treatment which improved the occlusal contact. The total length of the trajectory of the pressure center increased and decreased temporarily. This finding may be explained by the treatment-induced changes in occlusal contact, and short and stable trajectory length achieved by providing occlusion support.

Conclusion: The restoration with crowns and removable partial dentures was effective in improving the masticatory and esthetic disturbances, as well as oral health-related QOL in the elderly patient. Maintenance of posture was also improved.

Patient: The patient was a 72-year-old man with chief complaints of chewing deficiency and poor esthetic appearance in the anterior region. A denture with a metal-structured framework was made because the denture space was decreasing due to excessive occlusal force. The Functional Bite Impression (FGP) technique was used for fabricating metal teeth.

Discussion: The connecting metal framework and the wear resistance of metal teeth contributed to a remarkably rigid denture. The metal-structured denture could be delivered without occlusal adjustment.

Conclusion: Applying a metal-structured denture with a retainer type to a case with excessive occlusal force effectively protected the residual teeth and improved occlusion.

Patient: A 56-year-old female patient was referred to our hospital by a local dentist for the purpose of implant treatment. The patient initially complained of pain and a bad smell localized on the left side of the mandible. After root fracture of the lower left second premolar was diagnosed, the tooth was extracted.

Discussion: Two implant fixtures were implanted in the lower left edentulous area. After connecting a provisional restoration to the implants, the patient complained about an uncomfortable feeling during occlusion. Subsequently, the occlusal form was modified and the progress was followed up. The final cement-retained superstructure was installed with her consent. The prosthesis achieved stabilization of occlusal morphology and ease of maintenance.

Conclusion: It is suggested that good results can be obtained by reflecting the confirmation by provisional restoration in the final superstructure.

Patient: The patient was a 49-year-old female with complaints of masticatory disturbance and esthetic problem caused by missing teeth in the right upper jaw. Previously she had visited our hospital because of pus from the right nasal cavity and an abscess in the buccal gingiva of the upper first molar. Then several teeth with poor prognosis were extracted and prosthetic treatment using dental implants was considered.

Discussion: In this case, implant treatment with sinus lift to the region of bone mass deficiency was applied. After confirming the horizontal jaw position using an occlusal splint, the final prosthetic treatment was performed without change of the occlusal vertical dimension.

Conclusion: The patient has been satisfied with the final prostheses which were free from any problems such as fracture or detachment.

Patient: A 60-year-old female complained that her maxillary complete denture easily fell out when opening the mouth, making it hard to eat. Adaptation of the mucosal surface of the denture base was good, but the elasticity of the lip had decreased due to the scar from plastic surgery of the cleft lip, so it was considered that the maxillary complete denture was detached by the upper lip when opening the mouth. Accordingly, we made a dental prosthesis by acquiring a patient-specific denture space.

Discussion: It is considered that acquiring a denture space suitable for the oral cavity by utilizing functional motion and pronunciation for the maxilla with partially different lip elasticity led to good results.

Conclusion: By acquiring the patient-specific denture space, we were able to improve the main complaint and obtained good results.