Prosthodontic treatment and power control are inseparable. Regardless of whether you are aware of the fact or not, possible biological changes that may occur with prosthodontic treatment greatly influence the prognosis of the treatments. However, details of the possibility of bone resorption or bone formation due to the mechanical load and its biological background, the maintenance of homeostasis of the periodontal ligament and relationship between regeneration and force are still unknown. In this article, we briefly introduce these biological backgrounds which have been elucidated currently. In the section of bone regeneration and force, we introduced several clinical findings suspecting a close relationship between those with the literatures. In the section of the periodontal ligament regeneration and force, the specificity and clinical significance of the components of periodontal ligament tissue were introduced along with the literature. We hope that this paper would contribute to improve the prognosis of prosthodontic treatments in the future.

Although it is in the oral cavity after wearing various kinds of partial denture, the important thing is to manage the oral cavity so that the balance between the stability of the denture and occlusion of the denture wearing at the beginning. Various relationships, such as the support to the denture, the bracing to chewing and the retention as a whole of the denture, furthermore, the difference in demand of the patient's denture, the relationship between the patient and the dentist, synergistic relationship, affect prognosis. The prosthodontic treatments integrated into these various relationships desired as a patient's lifetime companion. And whatever treatment it is done, intraoral managements are essential, considering various balance.

To enjoy seeing, eating and talking together is the natural right of human beings. However, the disorders of maxillofacial prosthetic patients, due to cleft lip palate, tumor, trauma and so on, in mastication, deglutition, speech and esthetics are far more serious than those of general prosthodontic patients. It will be caused by a wide variety of the original disease and the defect shape. In addition, these disorders are left, not separately but having mutual effect to each other, as after-effects and cause mental and psychological suffering.

The ultimate purpose of maxillofacial prosthetics is to make the patients return to the normal and usual life, but it is so difficult for maxillofacial prosthetic treatment to fulfill the purpose. To bring out the results of maxillofacial prosthetic treatment at most and maintain the obtained results stably and for a long time, organic collaboration between medical and dental clinics is essential for each stage of preoperative conference, operative adjustment, postoperative prosthetic treatment and periodical observation after prosthetic insertion. It is also necessary for medical and dental clinics to share mutual recognition of fundamental items and to exchange of information.

I have been engaged in maxillofacial prosthetic treatment for thirty-nine years and describe the actual conditions of collaboration between medical and dental clinics.

Recently, consideration for aesthetics becomes more important for partially edentulous patients with removable partial dentures, so occasions to see patients wearing non-metal clasp dentures have increased. Although the Japanese Prosthodontic Society published the position paper showing clinical guidelines for using non-metal clasp dentures, there are still many unclear points, and there are a few cases where it is difficult to deal with correspondence after-insertion of the denture. In this paper, the thermoplastic resin materials for non-metal clasp denture were organized, and the present evidence and views on the effects of resin clasp on periodontal tissue were referred. Mechanism of retentive force and consideration of aesthetics were also referred. In addition, clinical attention points were described through basic cases.

In Japan, the construction of community-based integrated care system with the aim of "integrated care" of the offer system of acute care and long-term care service in the regional area (junior high school district) and proper supply system "community-based care" of the life support service is promoted.

In the management of this system, "clinical integration" of the professional including the dental professional becomes a premise, and normative integration (Vision Setup) which puts the care of the patient center at the core becomes a basis for this.

Purpose: This study evaluated by the questionnaire to dentist about the use situation and prognosis of the CAD/CAM crown for the purpose to make the CAD/CAM crown successful, and at application expansion to molars or anteriors.

Methods: Questionnaire was randomly carried out to CAD/CAM crowns for 2,000 dental clinics all over the country. Survey contents are disconnection of the clinical application, debonding and breakage, a future view of CAD/CAM crowns, patient evaluation, etc.

Results: Total debonding ratio was found to be 8.0% and slightly decreased from previous paper (9.1%). Cross sectional analysis in bonding problem cause, there were high correspondence again to no sandblasting treatment in this study. This could be expected since a lot of dental clinic newly started to implement CAD/CAM crown in their daily treatment and diffusion on adhesion step is still on the way. The other thing to be mentioned was either debonding ratio or breakage ratio is lower than the ones with the manufacturer recommended priming/cementing system. Patient evaluation was a reply which 98.9% has satisfied very highly.

Conclusions: Although there seems to be a lot of debondings, debonding ratio itself is decreasing nevertheless it is usually understandable for new NHI coverage would take some time. This fact would be worth to focus and specially be mentioned. While improving material strength and color reproducibility in the application expansion to molars or anteriors from now on further.

Patient: A male in his seventies complained of masticatory disorders with an unfitted maxillary denture. His maxillary artificial teeth and residual mandibular teeth were severely worn down probably due to excessive occlusal force. Full-mouth rehabilitation was undertaken in this case, utilizing full cast crowns for mandibular molars and composite resin artificial teeth for maxillary complete dentures, respectively.

Discussion: By utilizing dental materials having different wear resistance between mandibular and maxillary teeth, tooth wear was intentionally permitted. As a result, the severe occlusal force could be distributed, thus protecting the residual teeth and alveolar ridge from damage.

Conclusion: This case report describes the favorable clinical outcome of a patient whose excessive occlusal force was distributed by intentional wearing of artificial teeth of complete dentures.

Patient: A 41-year-old female patient, who underwent hemiglossectomy due to tongue and oral floor cancer, sought a treatment for the molar missing teeth of her left mandible. A provisional implant-supported fixed prosthesis was first provided after autogenous bone grafting. After functional training of tongue movements using a palatal augmentation prosthesis (PAP) and adjustment of the interim restoration, a definitive prosthesis was provided, which significantly improved her chewing function as evaluated by chewing function score.

Discussion: An acceptable treatment outcome was achieved by a multidisciplinary approach, whereby bone augmentation and rehabilitation of impaired function of the tongue were sequentially provided by specialists in each field.

Conclusion: A multidisciplinary approach is necessary in prosthodontic treatment for patients who undergo hemiglossectomy.

Patient: The patient was a 60-year-old man who had an eating disorder after the operation on right oral floor cancer (marginal resection of mandible, bilateral neck dissection, mandibular plate reconstruction, and left forearm free flap surgery) (squamous cell carcinoma, T2N0M0). In addition to eating problems, he complained about pronunciation difficulties and esthetic problems caused by lower lip tilting, and drooling owing to the difficulty of lip closure. An implant-supported overdenture was delivered after the implant treatment at 6|67, and helped improve eating problems.

Discussion: An implant-supported overdenture improved the masticatory function at both molar sides more dramatically compared to esthetic and pronunciation problems. The overdenture is functioning well owing to repair with an additional artificial tooth even after the loss of |5.

Conclusion: Implant-supported overdenture improved eating problems and QOL in the patient with mandible deficit.

Patient: A 46-year-old man visited our hospital complaining of difficulty in chewing and aesthetic failure because of the detachment of fixed partial dentures of the maxillary anterior region and mandibular molars. Removable partial dentures with root copings were delivered to the patient with excessive bite force, in order to avoid root fracture of the structurally compromised and endodontically treated abutment teeth.

Discussion: The denture insertion considering the supporting ability of abutment teeth improved functional stability and chewing ability. Moreover, high patient satisfaction was achieved.

Conclusion: The application of removable partial dentures supported by structurally compromised and endodontically treated abutments resulted in a satisfactory therapeutic effect for this patient with high bite force.

Patient: An 80-year-old male presented with the chief complaint of difficulty in chewing using a maxillary complete denture. From the maxillary anterior teeth to the right and left premolar teeth region, the residual ridge showed severe bone resorption and flabby gums. After examination, difficulty in chewing was diagnosed as dysmasesis arising from the incompatibility and malocclusion of the maxillary complete denture. By applying selective pressure impression and cross-bite arrangement of artificial teeth, a maxillary complete denture was newly fabricated.

Discussion: The use of selective pressure impression and cross-bite arrangement of artificial teeth improved the denture fitting and mechanical stability in chewing, resulting in a favorable prognosis.

Conclusion: The results suggested that selective pressure impression and cross-bite arrangement of artificial teeth were effective for severe residual ridge resorption and flabby gums.

Patient: The patient was a 76-year-old female who had chief complaints about the poor retention of the upper complete denture, esthetic dissatisfaction regarding the clasps of the lower partial denture and masticatory disturbance for hard foods. A favorable result was obtained by attaching an overdenture using a magnetic attachment.

Discussion: It is thought that using magnetic attachments for the lower partial denture with esthetic dissatisfaction regarding the clasps was effective for esthetic improvement, retention and stability of the dentures and the QOL of the patient.

Conclusion: For a case with only mandibular anterior teeth remaining, it is effective to use an overdenture.