Tissue regeneration is defined as regenerating the lost or damaged tissue, by various reasons including trauma and diseases, to original tissue structure. However the detailed mechanism of tissue regeneration is still not fully understood. The contribution of many types of cells in tissue regeneration might be a major reason why regeneration processes are complicated. In this article, we will introduce correlation between mesenchymal stem cells and immune cells in bone regeneration with our previous data.

Articulator is indispensable for fabricating prosthesis. Historically, the articulator has been developed by the pioneers’ efforts to start with a plaster articulator, to a hinge articulator, an average value articulator, a semi-adjustable articulator, and a fully adjustable articulator. Nowadays, it seems that semi-adjustable articulators are mainstream, but the free joint articulator and the hinge articulator are still frequently used.

This time, I would like to mention about the purpose of using the articulator, basic size and average value of the articulator, outline of the mandibular movement and its reproduction to the articulator, face-bow transfer, significance of the gothic arch, check bite and adjustment of the condyle path, and reproduction of the incisal path.

In super-aged society, there are characteristic demands for denture treatment which we did not experienced in several decades ago. Although high complicacy of patient’s condition would often be involved for the dental treatment because of the deterioration of the functional ability, higher success would be expected in order to fulfil the requirements from the patient, family and care givers. Not only the deterioration of the dexterity of the tongue, lip and cheek, but also the circumstances on eating would affect the design of denture prosthesis. The design suitable for eating with help of caregiver is apparently different from the design advocated by denture experts in several decades ago. Therefore, development of a new concept for denture fabrication which could easily fulfill the requirements of super aged edentulous patients is highly expected. Lower complete denture which is stable for 3 seconds when mouth opens approximately 3 cm wide would be a reasonable requirement for the healthy food intake for edentulous patients. In the present report, several clues for the diagnosis and treatment concept which fit the above mentioned conditions are reported, with some theoretical point of view. Combination of the objective evaluation method of denture stability and the way of coping with the results on the set would be helpful.

Current implant treatment has been designed to suit healthy individuals and outpatients, while suitable treatment for patients who are unable to attend dental visits because of old age, systemic disease, or nursing care requirements has yet to be determined. According to the Survey of Dental Diseases conducted by the Japanese Ministry of Health, Labor and Welfare in 2017, 2.7% of persons aged 35 years and over had dental implants, and implant treatment was provided to many patients up to 50–74 years of age. The number of individuals aged 65 years and over in Japan in 2015 was 33.84 million. This figure will only increase in the future; thus, we can predict that the number of people who require nursing care and dental implants will simultaneously increase in the medium- to long-term.

In this article introduce the “back-off strategy” for transitioning elderly implant patients through progressive stage of frailty. If the patient becomes difficult to self-clean, consider the implant fixed prosthesis transition to the IOD. Then, if the frailty of the patient progresses and increased ability for others to provide oral hygiene care, implant should “to sleep”. In this situation, conventional removable denture should be considered. Basic keys of the management of elder patients with implant prostheses in their mouth as follows;

1. Go to a dental office if you or your family are diagnosed with dementia

2. Transition to prosthesis easy to clean

3. Remove poor prognosis implants, or put implants “to sleep”

4. Alternative procedure from fixed to removable prosthesis

5. Conventional RPD/CD Solution

6. Oral care education for PT’s family or care providers

“Implant Treatment in the Super Aging Society” is into holistic and comprehensive medical care taking into consideration patients’ daily life and end-of-life care.

In Japan, where super aging is proceeding, extension of healthy life expectancy is an important issue. Many reports have been reported that oral health affects the general condition. Especially after the loss of teeth, restoration of proper artificial occlusion is related to systemic nutritional status and frequency of occurrence and survival rate of life. The importance of prosthodontic treatment is indicated.

Digitization of dentistry is progressing. Development and application of digital technology related to implant treatment are changing as well. In implant treatment, the concept related to implant placement has been transformed from a jawbone-oriented type to a prosthetic-oriented type. Workflow of prosthetic device-driven implant treatment was digitized from analog methods using film media. Computer aided dental procedure will be further advanced.

Purpose: When a dentist gives instruction on occlusion to patients, the way the patient receives the instruction differs among individuals, and the occlusal condition desired by the dentist cannot be reproduced in some cases. The purpose of this study was to compare occlusal force and occlusal contact area for three kinds of instruction on occlusion.

Methods: Thirty subjects with normal dentition were instructed to bite in three ways such as “Please close your mouth”, “Please bite” and “Please bite tightly”. The occlusal force and occlusal contact area were measured for each instruction and examined.

Results: Occlusal force increased significantly in the order of “close your mouth”, “bite” and “bite tightly”. The occlusal force when instructed to “bite” was approximately twice that when instructed to “close your mouth”, and the force when instructed to “bite tightly” was about 4 to 5 times that when instructed to “close your mouth”. Occlusal force in the male group was greater than that in the female group for all occlusal instructions. Occlusal contact area also increased significantly in the order of “close your mouth”, “bite” and “bite tightly”. The occlusal contact area when instructed to “bite” was approximately twice that when instructed to “close your mouth”, and the area when instructed to “bite tightly” was approximately 3 times that when instructed to “close your mouth”.

Conclusions: In this study, subjects understood the nuances of the words used by the dentists in giving occlusion instructions, but it turned out that the interpretation of how much bite force is needed differed among the individuals.

Purpose: Treatment with CAD/CAM composite crowns has become a common prosthodontic option in Japan; however, systematic preclinical education for CAD/CAM composite crowns has not been established in dental schools. In 2016, the Tohoku University School of Dentistry introduced a practice system for CAD/CAM composite crowns into the preclinical education of 4th year dental students. In this article, the contents of the system are introduced, with a discussion of the educational effects.

Materials and methods: In the 2016 preclinical class of fixed prosthodontics for 44 dental students (4th year), a series of CAD/CAM composite crown procedures, i.e., preparation of the upper second premolars, final impression-taking, production and scanning of the working cast, and computer-aided design and manufacturing processes, was performed using a dental simulator. At the end of the class, the tooth preparation skills of the students were evaluated with a scoring rubric. The efficacy of the practice system was assessed by comparison with the results of the same evaluation for 50 dental students in the 6th year who had not experienced the same practice for CAD/CAM composite crowns in their 4th year.

Discussion: The average total score of the 4th year students was significantly higher than that of the 6th year students. In particular, the scores of the 4th year students were superior to those of the 6th year students in terms of occlusal reduction and marginal continuity, width, and position. Therefore, computer-aided design and manufacturing using abutment teeth by the students themselves seemed to increase their preparation skills for CAD/CAM composite crowns.

Conclusions: This practice system provides tangible educational benefit to preclinical students by imbuing them with a systematic understanding of the workflow of the CAD/CAM composite crown treatment, thereby improving their motivation for subjective learning.

Patient: The patient was a 58-year-old man examined at our department with a chief complaint of mastication disorder and esthetic issues in the incisor region. Based on the test results, he was diagnosed as infraocclusion due to severe attrition and a loss of occlusal-supporting area.

Discussion: The maxillomandibular relationship was reset by using a removable occlusal splint based on an examination of mandibular movement and by revising the design of the final prosthesis considering the shape of the provisional restoration, resulting in a good prognosis.

Conclusion: In this case we succeeded in improving his chief complaint by selecting a reversible method for determining the position of the mandible in response to a significant change in mandibular position, integrating the condition of the provisional restoration into the final prosthesis, and performing functional assessments at each step.

Patient: The patient was a 53-year-old male who was referred by a head and neck surgeon for preoperative examination of pleomorphic adenoma extraction. After surgery, he had a defect in his left-side maxillary bone. A maxillary denture with obturator prosthesis using multiple Roach clasps was manufactured. One year and seven months after the denture for defective maxilla was installed, the retainer of the denture was damaged and so the denture was manufactured again.

Discussion: The remanufactured maxillary denture with obturator prosthesis has been used without problems for more than four years. We consider that this design reduces the lateral force which causes harmful stress on the abutment teeth.

Conclusion: The use of multiple Roach clasps as a retainer for the maxillary denture with obturator prosthesis reduced the harmful stress on the abutment teeth and allowed long-term stability.

Patient: A 76-year-old female presented with a chief complaint of occlusal pain in the basal seat mucosa of the mandibular right molar. This patient had non-vertical stop occlusion, and the pain was caused by the remaining maxillary teeth strongly contacting with the mandibular denture. A maxillary overdenture and a mandibular removable partial denture with a lingual apron as a major connector were fabricated.

Discussion: The pain disappeared and excellent results were achieved. This might have been the result of removing the pressure on the mandibular denture from the remaining maxillary teeth, improving the rigidity and preventing the depression of the mandibular denture.

Conclusion: By manufacturing a maxillary overdenture and a mandibular removable partial denture with a lingual apron for this case with non-vertical stop occlusion, pain was suppressed, and the chewing ability, oral-related QOL and satisfaction were improved.

Patient: The case of a 69-year-old woman who visited our clinic with a chief complaint of poor esthetic appearance of the full mouth is reported. She exhibited no toothache, but requested esthetic improvement of dental attrition and inappropriate restoration, and specified the use of a material that does not discolor or fracture for an extended period. As a result of the examination, the patient was diagnosed with severely attrited dentition with torus mandibularis, and inappropriate restoration.

Discussion: Using occlusal splints for the severely attrited dentition, stability of jaw function was established. By using a full zirconia crown that was both esthetically pleasing and strong, subsequent attrition was prevented.

Conclusion: By applying proper prosthetic treatment in this case of severely attrited dentition, the patient’s mastication ability and esthetic dissatisfaction were resolved.

Patient: The case was a 45-year-old female who complained of difficulty of chewing with her dentures for one year. She underwent new prosthodontic treatment with complete dentures and telescopic dentures. She was satisfied with the treatment results and achieved good masticatory function as well as oral health.

Discussion: The trailing edge of the maxillary complete dentures was trimmed to a point without inducing vomiting reflex. Favorable results were obtained for 3 years. However, considering the risk of fracture of the dentures, the placement of reinforcing wire into the palatal area of the complete dentures should be considered as a safety measure. The compatibility, occlusal relation and subjective assessment of the dentures require long-term follow-up.

Conclusion: The application of complete dentures and telescopic dentures for this patient with chewing difficulty and vomiting reflex improved her masticatory function and oral health.

Patient: The patient was a man aged 57 at his first visit. His occlusal contacts in the intercuspal position were unbalanced because of a partially edentulous dental arch and a scissors-bite. The final prosthesis was placed after stabilizing the occlusal posture with a maxillary occlusal splint, which was a treatment denture covering the occlusal surfaces of the remaining teeth.

Discussion: Using the face-bow transfer and cross-mounting technique, the elements of temporary occlusion with the treatment denture were reflected in the final denture, which allowed the patient to achieve improved mastication efficiency and mouth-related QOL.

Conclusion: In cases with unbalanced posture of the mandible, prior to installing the final prosthesis, it is important to establish occlusal support and stabilize the occlusal posture by a treatment denture.