Tooth loss causes a decrease in masticatory function. The condition of masticatory dysfunction induces high carbohydrate diet, while decreasing the intake of low Glycemic Index (GI) foods and nutrients such as protein, dietary fiber, antioxidants, vitamins, and minerals. Increase in the Glycemic Load (GL) and the condition of Protein-Energy Malnutrition (PEM) may increase a risk of metabolic syndrome, frailty, and Non-Communicable Diseases (NCDs). Here we present some case reports about the effect of health promotion shown in indexes of body composition and metabolism by the recovery of masticatory function with dental prostheses combined with intensive operation of health guidance, focusing on nutritional advice.

Masticatory ability levels of 71 subjects with tooth loss were evaluated before and after intervention of prosthodontic treatment. Body composition, blood pressure, and some blood data were investigated for 25 of the 71 subjects, with both prosthodontic treatment and health guidance, before the intervention and 90 days after the guidance for comparative evaluation.

Improvement in masticatory function by prosthodontic treatment was observed in all the 71 cases. Moreover, improvement in basal metabolism standard value (skeletal muscle mass), Body Mass Index (BMI), body fat percentage, visceral fat level, and protein sufficiency rate was observed in all the 25 cases of health guidance group. HbA1c was measured for seven subjects out of the health guidance group, and the value was improved in all seven cases.

It seems that tailor-made health guidance, conducted simultaneously with the restoration of masticatory function with dental prosthesis, is effective in preventing onset and deterioration of NCDs for patients with masticatory dysfunction.

Most of patients of prosthodontics in near future will be older people who need long-term nursing care with dysphagia. It is therefore important for prosthodontics to address oral frailty and dysphagia as a part of oral health management and dysphagia rehabilitation. A transdisciplinary team approach involved medical and dental professionals is essential for dysphagia rehabilitation. Dentists are very welcome to join because the oral function management including prosthodontics is limited to dentists. Therefore, prosthodontics in near future should have the new strategy from the perspective of supporting patients’ life through oral function and meal, instead of the conventional strategy such as the reconstruction of occlusion.

The mission of prosthetic dentistry, which is directly involved in the maintenance and improvement of Quality of Life, is to contribute to the society by restoring shape and function and providing prosthodontic treatments mached the needs of patients. Especially in the case of missing teeth, the role of dental technicians involved in the production of removable partial dentures which is essential for the treatment is also very important, and it is desirable to agree on the recognition for cases between dentists and dental technicians.

In more difficult clinical cases, “cooperation” and “collaboration” that make the best use of each other’s professionality are required, and as the results, it is possible to provide efficient treatments to patients.

Based on the clinical case in which the ideal was pursued and the appropriate removable partial denture was provided.

I would like to discuss the significance of “cooperation” and “collaboration” between dentists and technicians on the partial denture treatments in addition to prosthodontic treatments the prosthodontic specialists should aim for.

Digital technology that has developed in recent years has changed the traditional dental treatment, and a new treatment called digital dentistry has been developed. Digital workflow has many advantages, especially for fixed prosthodontic treatment by dental technicians. Because it differs from traditional dental procedures, there are still many unknowns as to what is clinically beneficial to dentists and dental technicians. By analyzing the current situation, we examined how digital dentistry affects fixed prosthodontic treatment.

Reading the debate on the selection between fix and removable implant superstructure for maxillary edentulous patients, I could clearly understand key points for the selecting options. Also I could draw common points from both papers as follows.

• It is quite important to understand the patient expectations and experience of prostheses as well as the degree of satisfaction for them.

• What and how patients place significances among influencing factors on satisfaction are quite different among cases.

• It is indispensable to make patients to understand the shortcomings and limitations for each treatment options, however it is not easy.

• In making treatment plan, so-called the concept of top down treatment is necessary, and the basis for that should be complete denture fabrication.

This debate provided a good chance to reconfirm the advantages of secondly splinting concepts which allow us to utilize merits of fixed and removable options and to cope with longitudinal changes.

Patient: The patient was a 50-year-old female who complained of masticatory and esthetic disturbance. The patient first visited AGU Hospital in 1993. Her remaining teeth showed many different types of clinical deterioration. These remaining teeth were used as the abutment teeth of the partial dentures. Magnetic attachments were selected for the prosthesis in order to maximize retention. Twenty years have passed since this treatment; the follow-up is reported here.

Discussion: Because of the lowered load point on the abutment teeth through the introduction of a magnetic attachment system and the resulting improvement in the crown-root ratio of the teeth, abutment tooth mobility was improved. Consequently, the long-term prognosis has remained stable.

Conclusion: Based on the stable long-term prognosis, we believe that this application of the magnetic attachment system for RPD has been successful.

Purpose: The position of the palatal bar plays a key role in oral discomfort upon swallowing in patients with partial dentures of the maxilla, however, its quantitative evaluation is difficult. We used a portable functional near-infrared spectroscopy (fNIRS) system to investigate the swallowing related changes in activity of the prefrontal cortex under simulated partial dentures with different palatal bar positions to objectively evaluate the magnitude of oral discomfort.

Methods: Thirty-one dentate young adults participated in the study. Participants swallowed a bolus of water while wearing a simulated palatal bar located in the anterior, middle and posterior positions of the maxilla. Prefrontal regional brain activity was recorded by a wireless fNIRS system. The averaged and normalized oxy-hemoglobin (oxy-Hb) responses were compared among palatal bar conditions. We also recorded fNIRS data when participants swallowed the same bolus of water without wearing the palatal bar. The cumulative differences in the oxy-Hb responses between with and without the palatal bar were compared across conditions. Subjective oral discomfort upon swallowing was also obtained using a visual analog scale (VAS).

Results: Swallowing-related prefrontal activity was the largest in the posterior palatal bar condition, especially in the frontal pole region. The cumulative differences in the oxy-Hb activity in the posterior palatal bar condition were significantly greater than in the middle palatal bar condition. Consistent with the fNIRS results, the mean VAS value showed a significant increase of discomfort with swallowing from anterior to posterior positions of the palatal bar.

Conclusion: Subjective swallowing difficulty increased in order of anterior, middle and posterior palatal bar positions. Changes in activity in the frontal pole were confirmed especially between the middle and posterior palatal bar conditions. These results suggest the possibility of using fNIRS as a method to objectively evaluate intraoral sensation.

Patient: The patient was a 73-year-old totally edentulous woman who complained of residual mucous membrane pain during mastication. Further examination indicated that masticatory disturbance had been caused by a dysfunctional horizontal maxillomandibular position. Masticatory disturbance was improved by fabricating new complete dentures with adequate horizontal maxillomandibular position.

Discussion: The horizontal maxillomandibular position of the initial dentures was improperly set. As a result, these dentures were not stable during mastication, resulting in masticatory disturbance. It was considered that masticatory disturbance was improved by established new complete dentures with adequate horizontal maxillomandibular position.

Conclusion: In the present clinical case, the inadequate horizontal maxillomandibular position caused the masticatory disturbance and gothic arch tracing was useful for fabricating new dentures to confirm the horizontal maxillomandibular position.

Patient: A 43-year-old patient complained of masticatory disturbance caused by the instability of a maxillary complete denture. The patient had a lower occlusal vertical dimension evident in the facial appearance, and alveolar bone resorption in the bilateral mandibular molars was confirmed. After endodontic treatment of the bilateral mandibular molars, recovery of the occlusal plane and occlusal vertical dimension was attained through occlusal reconstruction of the temporary dentures, mandibular overlay prosthesis, and the current maxillary complete denture. Based on the temporary dentures, recovery of the occlusal function was attained via a definitive prosthesis.

Discussion: Acquisition of the appropriate occlusal plane and occlusal vertical dimension through the occlusal reconstruction of temporary dentures improved masticatory function.

Conclusion: In cases of instability of maxillary complete denture caused by occlusal plane disorder and lower occlusal vertical dimension, the recovery of function via occlusal reconstruction of temporary dentures results in a good prognosis.

Patient: A 61-year-old man visited our hospital complaining of occlusal pain of the mandibular right first molar. Masticatory disturbance due to chronic periapical periodontitis and substantial tooth defect beyond the alveolar crest was diagnosed. Intentional replanting was carried out to preserve the mandibular right first molar. Four months after the operation, prosthetic treatment by a hybrid resin jacket crown was performed.

Discussion: Although the problem has not recurred for ten years, hybrid resin is likely to cause changes in the occlusal state and loss of gloss in comparison with metals and ceramics, and so attention is necessary when recalling.

Conclusion: The mandibular right first molar was preserved by intentional replanting and a single crown, and the patient was able to be satisfied for a long time.

Patient: The patient was a 63-year-old woman. Her chief complaints were esthetic dissatisfaction in the maxillary and mandibular anterior region and difficulty in chewing due to bilateral missing molars. She had generalized severe chronic periodontitis and infraocclusion with flared anterior teeth. The occlusal vertical dimension was increased by provisional restoration with dental implants for occlusal reconstruction. Orthodontic treatment was performed and a fixed implant-supported prosthesis was fabricated for maxillary bilateral free-end with flared anterior teeth.

Discussion: The patient has been recalled periodically since the final prostheses were delivered. The patient was very satisfied with the treatment without any specific problems during the 12-year follow-up period.

Conclusion: The patient had a good prognosis because the implant treatment with bite rising mitigated her dissatisfaction caused by decreased vertical dimension and improved the mandible crowding and flared anterior teeth.

Patient: The patient was a 68-year-old male with the chief complaint of difficulty on mastication caused by unsteadiness of dentures and chronic periodontitis of abutment teeth. A diagnosis of non-vertical stop occlusion was made. After extraction of the incisor and molar that were causing the problem, recovery of masticatory function was attained through the fabrication of a removable partial denture (RPD) with metal framework and proximal plates.

Discussion: Mastication ability was improved with the metal base denture owing to restriction of denture rotation and increased stability of the RPD, leading to improvement in both objective and subjective assessments of the effectiveness of the treatment.

Conclusion: The RPD with a metal framework yielded effective results for this particular case of non-vertical stop occlusion.